Journal of Vision (2007) 7(8):12, 17
http://journalofvision.org/7/8/12/
An unusual kind of contrast adaptation: Shifting a contrast comparison level

S. Sabina Wolfson

Norma Graham
Department of Psychology, Columbia University, New York, NY, USA
We have found an unusual kind of contrast adaptation in human pattern vision that seems fundamentally different from previously reported effects. As the observer adapts to different levels of contrast, the visibility of some contrast-dened (second-order) patterns dramatically increases and that of others dramatically decreases. Oddly, visibility is poor for patterns containing contrasts both above and below the recent average contrast. To explain these effects, we hypothesize a new kind of process acting in concert with a known contrast-gain control of the normalization type. The new process compares current contrast to an adaptable comparison level; this level reects the recent average contrast. Such a process existing at an early stage of visual processing is likely to have widespread effects at higher stages. Keywords: human vision, psychophysics, adaptation, contrast, texture, pattern, second-order Citation: Wolfson, S. S., & Graham, N. (2007). An unusual kind of contrast adaptation: Shifting a contrast comparison level. Journal of Vision, 7(8):12, 17, http://journalofvision.org/7/8/12/, doi:10.1167/7.8.12.

Introduction

There are many dimensions along which the visual system adapts (e.g., luminance and color). Without adaptation, the system would function very poorly. We have recently discovered a kind of adaptation to the contrast of visual patterns that is dramatic in magnitude and has qualitative characteristics very different from those previously reported. (In presenting work at conferences, we sometimes call this kind of contrast adaptation Buffy adaptation. The origin of that term is described in Graham & Wolfson, 2007). Sensory and perceptual adaptation processes occur at time-scales that range from many minutes (e.g., dark adaptation, contingent aftereffects like the McCollough effects) to fractions of a second, short enough to happen within a xation (e.g., Muller, Metha, Krauskopf, & Lennie, 1999). The effect we present here is relatively rapid (1 s adapting duration). The experiment sketched in Figure 1 demonstrates this new kind of contrast adaptation. The observer adapts for 1 s to a grid of identical Gabor patches all at some contrast, for example, 50%. Then, the observer views a brief test stimulus (for 94 ms). The test stimulus is composed of Gabor patches at two different contrasts in alternating rows (or columns), producing contrast-dened stripes that are either horizontal (as in Figure 1) or vertical. Then, the observer views the same adapt stimulus again for 1 s. The observer identies the orientation of the contrast-dened stripes in the test stimulus.

doi: 1 0. / 7. 8. 12

Figure 1 shows three types of test stimuli that are particularly telling. In the BELOW test stimulus, the two contrast values that produce the stripes, 25% and 45%, are both below the adapt contrast of 50%. In the STRADDLE test stimulus, the contrasts straddle the adapt contrast, and in the ABOVE test stimulus, they are both above it. In each of these test stimuli, the contrast difference (between the two contrast values that produce the stripes) is always the same (20%). In general, observers perform very poorly on the STRADDLE test stimulus and very well on both the ABOVE and BELOW test stimuli. This was an unexpected result and implicates an unusual kind of contrast adaptation that adjusts a contrast-comparison level based on the recent average contrast.

Methods

All observers were Columbia University undergraduates with normal (or corrected-to-normal) visual acuity. They were paid for their participation. Observer R.K. is listed twice (rk1 and rk2) since she ran the whole experiment twice (the second time, intermixed with sessions from additional conditions not reported here). The experiments were run on a Macintosh G4 with an Iiyama VisionMaster Pro 451 CRT and an ATI Radeon 8500 Mac edition video card. The resolution was 1,280 1,024 pixels at 85 Hz. The mean luminance was about 50 cd/m2. The monitors look-up-table was linearized. Stimuli were generated and presented using MathWorks

ISSN 1534-7362 * ARVO

Received February 16, 2007; published June 25, 2007

Wolfson & Graham

Figure 1. One adapt stimulus and three possible test stimuli are illustrated here as grids of Gabor patches. (The stimuli used in the experiment were grids.). The time-course of the experiment is drawn at the left side. Contrast differences in the gray-level illustrations shown here were exaggerated to increase their salience. The contrast of the adapt stimulus (Adapt Contrast) is the contrast of the Gabor patches in that stimulus (50% in this example). The contrast values in the test stimulus (Test Contrast 1, Test Contrast 2) are the contrasts of the two kinds of Gabor patches making up the test stimulus and are enclosed in parentheses on the gure. The Average Test Contrast is the average of these two values.
MATLAB with the Psychophysics Toolbox extensions (Brainard, 1997; Pelli, 1997). Each stimulus was a grid of Gabor patch elements. (A Gabor patch is a sinusoidal grating windowed by a two-dimensional Gaussian function.) Each Gabor patch was truncated at 1 1- (pixels) at the viewing distance of 90 cm. (Distances are approximate as observers
heads were not constrained.) The center-to-center Gabor patch distance was 64 pixels. The sinusoidal grating in our Gabor patches had a period of 0.5- (32 pixels), which is a spatial frequency of 2 c/deg. In each Gabor patch, a positive zero-crossing of the sinusoidal grating was centered under the Gaussian function. The Gaussian function had a fullwidth-at-half-height of 0.5- (32 pixels). The contrast of a
Gabor patch is computed by taking the difference between the luminance at the peak of the Gaussian and the mean luminance of the pattern and then dividing that difference by the mean luminance. Each trial proceeded as follows: The observer pressed the 0 key to start the trial, the screen was gray for 500 ms, the adapt pattern was shown for 1 s, the test pattern was shown for 94 ms, the adapt pattern was shown again for 1 s, the screen was gray for 100 ms, and then the computer beeped, indicating that the observer had to respond. The screen remained gray between trials. The mean luminance was constant throughout the experiment. The observers task was to identify the orientation (vertical or horizontal) of the contrast-dened stripes in the test pattern using the computers keyboard. Feedback was provided. The room was dark. There were four different test pattern congurations: (1) horizontal (second-order) stripes composed of horizontal (rst-order) Gabor patch elements, (2) horizontal stripes of vertical elements (as in Figure 1), (3) vertical stripes of vertical elements, and (4) vertical stripes of horizontal elements. The orientation of the Gabor patches was always the same throughout a trial. There were three adapt contrasts: 35%, 50%, and 65%. The difference between the contrasts of the two element types in the test patterns was always either 10% or 20%. Within a session, trials of all combinations of adapt and test stimuli were intermixed. Not all test stimuli were used with all adapt contrasts in this particular experiment. For example, the data points in Figure 2 show all combinations of test stimuli and adapt contrast used with a 20% contrast difference. Each session was 320 trials long. Each subject ran at least nine sessions, and thus, each point in Figures 2 and 3 represents at least 72 trials.

Results

Figure 2 shows results (from an experiment like that in Figure 1) after adapting to three different contrast levels (35% in red, 50% in black, and 65% in blue). The vertical axis shows the percentage correct identication of the orientation of the contrast-dened stripes of the test stimulus. The horizontal axis shows the average of the two contrasts in the test stimulus. The difference between these two contrasts is always 20%. Performance is severely impaired when the average test contrast equals the adapt contrast. For example, each 35% adapt contrast (red) curve has a minimum at an average test contrast of 35%, which corresponds to a STRADDLE test stimulus composed of 25% and 45% contrast Gabor patches. And performance is near perfect to the right of the minimum (ABOVE test stimuli) and to the left of the minimum (BELOW test stimuli). This same pattern of results (poor performance for the STRADDLE test stimulus and very good performance on ABOVE and BELOW test stimuli) is seen for all three of the adapt contrasts. Another way of thinking about the results in Figure 2 is to consider all the data points directly above a particular average test contrast on the horizontal axis, for example, 65%. The observers were near perfect on this test stimulus (containing 55% and 75% contrast Gabor patches) if they had previously adapted for 1 s to 35% contrast (red) but much worse if they had adapted to 65% contrast (blue). Adaptation so dramatically alters the observers ability to see contrast-dened patterns that it can change performance on patterns from near perfect to near chance, or vice versa, depending on what contrast the observer has recently seen.
Figure 2. Results from an experiment like that illustrated in Figure 1. The difference between the two contrast values in the test stimulus was always 20%. Observers (indicated by different symbols) adapted to a grid of identical Gabor patches of either 35% (red solid line), 50% (black dashed line), or 65% (blue dash-dotted line) contrast. Error bars show T 1 SEM across sessions. Performance is very good on ABOVE and BELOW test stimuli and poorer on STRADDLE test stimuli.
Figure 3. Results from stimuli in which the transient the absolute value of the maximum change between adapt stimulus and test stimulus was always 10%. Other conventions as in Figure 2. Performance is still poor on STRADDLE test stimuli and very good on ABOVE and BELOW test stimuli, even when the transient is held constant.
Some readers may have worried that, while the difference between the two contrasts in the test stimuli in Figure 2 is always 20%, this difference might not be the same in all cases in the following sense. Consider the absolute value of the maximum change (called the transient below) between the two contrasts in a test stimulus and the adapt contrast. In particular, consider a 50% adapt contrast. For the STRADDLE test stimulus, which consists of contrasts 40% and 60%, the transient is just 10%. However, the transient is 20% for the ABOVE test stimulus composed of 50% and 70% contrasts and also 20% for the BELOW stimulus composed of 30% and 50% contrasts. It is greater than 20% for any other ABOVE or BELOW test stimulus. Figure 3 shows the results for three test stimuli in which the transient (the absolute value of the maximum change) is always 10%. The pair of contrast values in each test stimulus is shown on the horizontal axis. The adapt contrast was 50%. The vertical axis shows percent correct identication.

Clearly, even when the transient is the same, observers perform more poorly on the STRADDLE test stimulus than on the ABOVE and BELOW test stimuli.

Discussion

What kind of visual process could produce results like those in Figures 2 and 3?
It is straightforward to show that rectication on a luminance dimension (as in conventional complex or second-order channelsVGraham & Sutter, 1998; Landy & Graham, 2003; Schoeld, 2000) cannot produce results like those of Figures 2 and 3, nor can contrast-controlled adaptation processes of the types often called (see, e.g., Ibbotson, 2005) contrast-gain controls (sketched in Figure 4,
Figure 4. Contrastresponse functions from three different kinds of contrast-controlled adaptation mechanisms. The solid line in each panel is the curve after adaptation to one level of contrast. The dashed line is the curve after adaptation to another higher level of contrast. Monotonic contrastresponse functions have been assumed to shift generally horizontally (left panel) and/or vertically (middle panel) by adaptation processes. In the adaptation mechanism we propose (right panel), a non-monotonic rectifying function moves horizontally, changing the position of the bottom of the V (the comparison level) to equal the recent average contrast.
left panel) or response-gain controls (Figure 4, middle panel) since neither can produce the selectively poor performance in the STRADDLE conditions. (One can consider the functions in Figure 4 as characterizing individual neurons, or as characterizing a suitable group of neurons, or as a more abstract description of a process in a psychophysical model.) An adaptable comparison process operating on the dimension of contrast (Figure 4, right panel) can explain our results, at least qualitatively. In this process, the function relating response to contrast at each image spatial position is a non-monotonic rectifying function. The contrast value at the minimum of the function will be called the comparison level. Adaptation moves the function horizontally by updating the comparison level at a spatial position to equal the recent time-averaged contrast in some neighborhood around that position. Thus, the output of this process is the un-signed difference between the current contrast at a position and the comparison level there. Increments in contrast produce approximately the same outputs as decrements of similar magnitude. In this sense, increments and decrements are confusable by the comparison process. If the function in Figure 4 (right panel) were indeed a perfect full-wave rectifying function, then performance by this mechanism on STRADDLE test stimuli would be at chance, no matter how high the contrast difference, a result we have not found with any observer we tested. Overcoming this and other difculties with the idea in Figure 4 (right panel) can be accomplished in a number of different ways while incorporating an adaptable comparison process into standard models of pattern vision that include simple (linear) and complex (second-order) channels sensitive to different ranges of spatial frequency and orientation. For example, one can assume that the function shown in Figure 4 (right panel) is not a perfect full-wave rectication but something between a half-wave and a full-wave linear rectication (where the asymmetry can be in different directions in different channels). Or one can assume a function that is not even piecewise linear (due, perhaps, to an early logarithmic transformation). Alternately, one might assume that there are not only channels incorporating this new process but also channels that do not. All these various possibilities have testable consequences. We are currently investigating the quantitative success of such extended models and trying to distinguish among them.

adapted to 0% contrast (blank gray eld), so we would not have seen this adaptation. To our knowledge, the only other situations in which visual adaptation introduces confusion or lack of discriminability between values on either side of the adapting value are situations in which the adaptation occurs not on the contrast dimension but on high-level dimensions like those describing face perception (Rhodes et al., 2005; Rhodes, Maloney, Turner, & Ewing, 2006).
Why has this form of adaptation evolved?
Most of the functions suggested for perceptual adaptation (e.g., in Clifford & Rhodes, 2005) belong in one of two classes, and to some extent, both classes may apply to the adaptation phenomena here: 1. To re-center the operating range of the system to be at or near the current adaptation level (the average level in the recent past of whatever kind of input is at issue) so that performance is optimized near that level. The function of light adaptation is widely believed to be of this sort. 2. To suppress the response to unchanged visual stimuli and thereby highlight the responses to changes because changes signal important events in the environment and/or to make neural coding more efcient. Consider the rst class of explanation: An operating range seems to be moving in Figure 2 as the adapt contrast changes, but the movement seems to make performance worse near the adapting level, not better. However, not illustrated in Figure 2 is one important fact well established from our prior work: Without any previous adaptation to pattern contrast (more exactly, after adaptation to a blank gray eld, i.e., to 0% contrast), performance on most of the test stimuli in Figures 2 and 3 would be very poor, but performance would be very good on test stimuli of even lower average test contrast than that plotted. Indeed, in the absence of adaptation to non-zero contrast, performance for the test stimuli plotted at the right end of Figures 2 and 3 would be close to or at chance (e.g., Graham, Beck, & Sutter, 1992; Graham & Sutter, 2000; Wolfson & Graham, 2005). Thus, adaptation to a non-zero pattern contrast of 35%, 50%, or 65% in Figure 2 can be said to move the operating range to the right relative to that without pattern adaptation, thus producing better performance than before on the test patterns near the adapting level (except for STRADDLE stimuli). Results after adaptation to a blank gray eld (0% contrast) have been successfully explained by incorporating into the model a contrast-gain control of the normalization type which acts on the outputs of both simple (rst-order) and complex (second-order) channels (e.g., Graham et al., 1992; Graham & Sutter, 2000). The adaptable comparison process proposed here and that previously-identied contrast-gain control (of the

Why has this comparison-level process not been suggested before?
We think that this kind of adaptation effect was not noticed earlier because experimenters, in general, have not tested pattern discriminations like those here after adapting to different contrasts. For example, all of our own past experiments using this kind of pattern discrimination only
normalization type) work together. The consequence of their combined action is that most patterns near the adapt contrast (all except for STRADDLE patterns) are easy to perceive, but patterns composed of contrasts far away from the adapt contrast are difcult to perceive. One might describe the result here (Figures 2 and 3) in words appropriate to the second class of proposed function: As a consequence of the action of the adaptable comparison process, the visual system is very sensitive to (most) contrast changes from the adapting level to new but nearby contrast levels (the test levels). These changes can be used by the system to identify features like the orientation of contrast modulation here, as long as the changes do not straddle the initial contrast. In short, the system responds to change well, consistent with this second class of proposed function, but loses information about the sign of the change. Thus, both classes of explanation may provide some understanding of why this kind of contrast adaptation exists, but neither class helps us understand the very poor performance on STRADDLE test stimuli. Perhaps, wiring a neural system so that it can signal a change quickly without regard to sign is much less costly (in terms of whatever kinds of costs that limit evolution of neural tissue) than wiring a system to signal quickly both a change and its sign. If so, we do not understand why it might be so. Or, perhaps, there is some evolutionary advantage to not being able to perform well on those stimuli. But, if so, it is a mystery to us.
considered previously. It is worthwhile doing so. Any adaptation that occurs at relatively low levels of visual processing will affect the later processes of visual perception. The adaptation described here may be particularly important for the perception of shape and form.

Acknowledgments

This work was supported in part by National Eye Institute Grant EY08459. Some of the results from this experiment were presented at the Spring 2006 VSS meeting (Graham & Wolfson, 2006). We thank our observers for their hours of effort. Commercial relationships: none. Corresponding author: S. Sabina Wolfson. Email: sabina@psych.columbia.edu. Address: Department of Psychology, Columbia University, 406 Schermerhorn Hall, New York, NY 10027.

References

Brainard, D. H. (1997). The Psychophysics Toolbox. Spatial Vision, 10, 443446. [PubMed] Carandini, M., Demb, J. B., Mante, V., Tolhurst, D. J., Dan, Y., Olshausen, B. A., et al. (2005). Do we know what the early visual system does? Journal of Neuroscience, 25, 1057710597. [PubMed] [Article] Clifford, C. W., & Rhodes, G. (2005). Fitting the mind to the world. Oxford, UK: Oxford University Press. Gardner, J. L., Sun, P., Waggoner, R. A., Ueno, K., Tanaka, K., & Cheng, K. (2005). Contrast adaptation and representation in human early visual cortex. Neuron, 47, 607620. [PubMed] [Article] Graham, N., Beck, J., & Sutter, A. (1992). Nonlinear processes in spatialfrequency channel models of perceived texture segregation: Effects of sign and amount of contrast. Vision Research, 32, 719743. [PubMed] Graham, N., & Sutter, A. (1998). Spatial summation in simple (Fourier) and complex (non-Fourier) texture channels. Vision Research, 38, 231257. [PubMed] Graham, N., & Sutter, A. (2000). Normalization: Contrastgain control in simple (Fourier) and complex (nonFourier) pathways of pattern vision. Vision Research, 40, 27372761. [PubMed] Graham, N., & Wolfson, S. S. (2006). Complex channels become more complex: Modeling a contrast adaptation process [Abstract]. Journal of Vision, 6(6):694, 694a, http://journalofvision.org/6/6/694/, doi:10.1167/ 6.6.694.
Where in the nervous system might this adaptable comparison process exist?
Single neurons in cortical area V1 have been extensively studied (see, e.g., Carandini et al., 2005), but nothing like this adaptable contrast-level comparison process has ever been reported. Gardner et al. (2005) looked at human fMRI BOLD responses from populations of neurons in V1, V2, V3, and hV4 to changes in test stimulus contrast. They found that V1, V2, and V3 responses are positive to increments in test stimulus contrast from adapting contrast and negative to decrements. Responses in hV4, however, are positive to either increments or decrements in contrast from an adapting contrast. This confusion of increments and decrements is consistent with a possible role for hV4 in the comparison process of Figure 4 (right panel). Further, human fMRI data from Larsson, Landy, and Heeger (2006) strongly suggest that stimulus orientation in second-order tasks such as ours is extracted largely in VO1 (but also V3A/B and LO1), all areas beyond V1 and V2.

Consequences

The possible consequences of contrast adaptation like that proposed here (Figure 4, right panel) have not been
Graham, N., & Wolfson, S. S. (2007). Exploring contrastcontrolled adaptation processes in human vision (with help from Buffy the Vampire Slayer). In L. R. Harris & M. R. M. Jenkin (Eds.), Computational vision in neural and machine systems (pp. 947). Cambridge, UK: Cambridge University Press. Ibbotson, M. R. (2005). Physiological mechanisms of adaptation in the visual system. In C. W. G. Clifford & G. Rhodes (Eds.), Fitting the mind to the world (pp. 1546). Oxford, UK: Oxford University Press. Landy, M. S., & Graham, N. (2003). Visual perception of texture. In L. M. Chalupa & J. S. Werner (Eds.), The visual neurosciences (pp. 11061118). Cambridge, MA: MIT Press. Larsson, J., Landy, M. S., & Heeger, D. J. (2006). Orientation-selective adaptation to rst- and secondorder patterns in human visual cortex. Journal of Neurophysiology, 95, 862881. [PubMed] [Article] Muller, J. R., Metha, A. B., Krauskopf, J., & Lennie, P. (1999). Rapid adaptation in visual cortex to the structure of images. Science, 285, 14051408. [PubMed]
Pelli, D. G. (1997). The VideoToolbox software for visual psychophysics: Transforming numbers into movies. Spatial Vision, 10, 437442. [PubMed] Rhodes, G., Maloney, L. T., Turner, J., & Ewing, L. (2006). Is the average face special [Abstract]? Journal of Vision, 6(6):283, 283a, http://journalofvision.org/ 6/6/283/, doi:10.1167/6.6.283. Rhodes, G., Robbins, R., Jacquet, E., McKone, E. Jaffery, L., & Clifford, C. W. G. (2005). Adaptation and face perception: How aftereffects implicate norm-based coding of faces. In C. W. G. Clifford & G. Rhodes (Eds.), Fitting the mind to the world (pp. 213240). Oxford, UK: Oxford University Press. Schoeld, A. J. (2000). What does second-order vision see in an image? Perception, 29, 10711086. [PubMed] Wolfson, S. S., & Graham, N. (2005). Element-arrangement textures in multiple objective tasks. Spatial Vision, 18, 209226. [PubMed] [Article]

PHOTOMOD 4.4 Overview

USER MANUAL

Racurs, Moscow, 2009

PHOTOMOD 4.4
1. PHOTOMOD system and RACURS Company... 4 2. Distribution kit..... 5 3. Personal computer requirements.... 5 3.1 Operating systems.... 5 4. Installation, starting and deinstallation... 6 5. Protection.... 8 6. Resources and networking.... 9 7. PHOTOMOD network version.... 10 7.1 General info.... 11 7.2 Resources storage in PHOTOMOD system... 12 7.2.1 Recommendations for the storages creation... 12 7.2.2 Storages creating..... 13 7.2.3 Resources access setup.... 14 7.2.4 Filling storages while working with a project... 15 8. PHOTOMOD local version.... 15 9. PHOTOMOD System Monitor module... 16 10. PHOTOMOD Control Panel.... 17 11. PHOTOMOD Explorer.... 19 12. Geodetic calculator.... 23 13. PHOTOMOD MSTiff Maker utility.... 26 14. PHOTOMOD RasterView utility.... 28 14.1 Image printing..... 29 14.1.1 Printing settings..... 30 15. Service tools..... 31 15.1 Miscellaneous Utilities program.... 31 15.1.1 Search & Replace in DGN files.... 31 15.1.2 Merge DGN files.... 32 15.1.3 Fill sheets by polygons.... 32 15.1.4 Replace font size in MIF/MID files... 33 16. Equipment for stereo measurements... 34 16.1 Stereoglasses..... 34 16.2 Video cards.... 36 16.2.1 Driver setup.... 38 16.3 Monitors.... 40 16.3.1 Stereo monitors..... 41 16.4 Mice and hand wheels adjustment for stereo processing.. 43 16.4.1 Three and five button mice... 46 16.4.2 Immersion SoftMouse.... 47 16.4.3 GeoMouse.... 48 16.4.4 Stealth 3D Mice..... 50 16.4.4.1 Stealth 3D Mouse-U.... 50

Overview

July 25, 2009
16.4.4.2 Stealth 3D Mouse-Z.... 52 16.4.5 Hand wheels and foot pedals.... 55 16.4.5.1 Immersion compatible hand wheels and foot pedals.. 55 16.4.5.2 Hand wheels and foot pedals Vector-A.. 56 16.4.6 Macro editor.... 58 16.5 Hardware settings for working in stereomode... 62 17. Distributed processing..... 64 17.1 General information.... 64 17.2 Initial setup..... 65 17.3 Monitoring distributed processing... 66 17.3.1 Tasks in queue.... 66 17.3.2 Computers.... 67 17.3.3 Finished tasks.... 68 18. Acknowledgments.... 70 19. Glossary..... 71
RACURS Co., Ul. Yaroslavskaya, 13-A, office 15, 129366, Moscow, Russia
1. PHOTOMOD system and RACURS Company
PHOTOMOD is a digital system providing full photogrammetric production line from the aerial triangulation to output digital terrain models, digital maps and orthomosaics. PHOTOMOD system contains tools for processing aerial photos and scanner satellite images from different sensors such IKONOS, QuickBird, SPOT, IRS, ASTER, FORMOSAT, CARTOSAT, etc. Due to the system modular structure the user can choose the necessary configuration when purchasing the software. Network system version opens wide opportunities of working with a project simultaneously from several workplaces. PHOTOMOD system is produced by Racurs Co. (Moscow, Russia) and has been dynamically developing since version 1.1 in 1994. PHOTOMOD's growing user base includes organizations throughout more than 45 countries worldwide. The main fields of application include photogrammetric production, cadastral mapping, cartography and remote sensing, academic photogrammetry, mining, architecture and construction. You can get the additional information about Racurs and PHOTOMOD from: Racurs web-site: www.racurs.ru E-mail: info@racurs.ru Phone: (+7-495) 720-5127 Fax: (+7-495) 720-5128 Mail: RACURS Co., Ul. Yaroslavskaya, 13-A, office 15, Moscow, Russia
Fig.1 Digital Photogrammetric Workstation PHOTOMOD

2. Distribution kit

Fig.2 Distribution kit The PHOTOMOD system distribution kit includes: - CD-ROM containing the system setup files and the documentation files in PDF format - hard lock key
3. Personal computer requirements
The recommended PHOTOMOD workstation configuration may be as follows: CPU: Pentium 4; 3.0 GHz, or similar RAM: 1-2 Gb For effective networking: network card 1000 Mb/s HDD: you should keep in mind that working with big enough projects requires a considerable amount of the disk space. For example, the standard aerial image 23 by 23 cm scanned with 20-mkm resolution (1200 dpi) is about 400 MB in uncompressed mode in PHOTOMOD image format (TIFF with a pyramid). If you use jpeg compression with a quality 80 percent, the image file size is about 80 MB. Graphic card: see the chapter 15 Equipment for stereo measurements.

Convenient way of data sharing. No matter on what computer in the network a particular resource is located, this resource appears in "Load/Save" dialogues immediately. There is no need to select different folders as when working with ordinary files. Fast access to network resources. If it complies with company security rules PHOTOMOD can be configured to automatic network password enter when accessing storages located on remote computers.
PHOTOMOD Explorer which is used for resources management has the user interface similar to Windows Explorer interface. This module provides the possibility to view and edit most of PHOTOMOD resources as well as many other useful service functions. See the chapter 11 PHOTOMOD Explorer. Montage Desktop module allows to backup projects in the form of ordinary folders and files and also to restore projects from backup copies to the system of PHOTOMOD resources. Backupped projects can be restored with network configurations different from that was used when backup was created. Restored projects are ready to use without any further adjustment. PHOTOMOD Control Panel utility allows to control the access to storages and free space in them. It is also possible to connect/disconnect storages. See the chapter 10 PHOTOMOD Control Panel. Rich experience of Racurs company production department gives rise to the following recommendations concerning storages configurations and data distribution: For local configurations (when there is only one PHOTOMOD workplace or only one operator works with each project and data exchange between workstations is not considerable) it is recommended to create local storages at each workstation to benefit from higher local disk access speed versus access speed through the local network. For network configurations when project data are processed simultaneously by many operators from different workstations it is recommended to have a special server which is not used as a workstation and place the storage (storages) on it. It is not recommended to store shared data on a computer used as a workstation because of increased danger of computer failure and hence failure in data access. This does not increase essentially the probability of data loss but decreases the overall productivity. When preparing a computer for working as a file-server please pay special attention to selection and configuring of operating system. Microsoft Windows 2000 Server or FreeBSD is recommended. Both these systems showed best results in testing as servers in the photogrammetric production line. If you are going to store data on a computer with nonserver version of Windows (NT, 2000 or XP), please take into account that such operating systems have a restriction on the number of network connections and if more than 10 computers are in the LAN, simultaneous work will be difficult or impossible. PHOTOMOD system has a lot of other service functions to facilitate working with large volume of photogrammetric data.

9. PHOTOMOD System Monitor module
After PHOTOMOD system installation PHOTOMOD System Monitor (PhMonitor.exe). If the module is launched. It is visualized in OS Windows System tray as an icon module was not launched for some reason, you should start it from Windows Start menu: Start | Programs | PHOTOMOD | Utility | PHOTOMOD System Monitor.
Fig.8 Pop-up menu of PHOTOMOD System Monitor When PHOTOMOD system is ready to work, the icon in System tray turns from sandglass into grey ball. Besides, if some PHOTOMOD storage is unavailable yellow triangle with exclamation mark is added to the icon. Context menu of PHOTOMOD System Monitor module is opened after right click on the ball and contains the following commands: PHOTOMOD Montage Desktop starts the main PHOTOMOD system module PHOTOMOD Montage Desktop (also is launched using double click on the afterwards starts the work in PHOTOMOD system icon) and
Control Panel to start an appropriate application (see the chapter 10 PHOTOMOD Control Panel) PHOTOMOD Explorer to start an appropriate application (see the chapter 11 PHOTOMOD Explorer) Distribution info opens a window with information on PHOTOMOD modules configuration and hard lock key ID. You can save the information to text file and send it to tech. support service Mouse configuration allows to setup a configuration of mice or other special devices (like hand wheels/foot pedals), which are used for images stereo processing (see the chapter 15.4 Mice and hand wheels adjustment for stereo processing) Enable sound allows to turn on/off the sound which accompanies opening or closing of PHOTOMOD System Monitor module About opens a window indicating the number of system build and serial number of hard lock key Exit closes PHOTOMOD System Monitor module and exits from PHOTOMOD system.
10. PHOTOMOD Control Panel
PHOTOMOD Control Panel program is used to setup and control the local network for working with the PHOTOMOD system. Use the following way to start PHOTOMOD Control Panel: Start | Programs | PHOTOMOD | Utility | PHOTOMOD Control Panel. Besides, it could be started from Montage Desktop module using menu command Project | Open/Management and the icon Control Panel (see Montage Desktop User Manual),
or also use right mouse click on the icon (PhMonitor) in OS Windows System tray, and select then pop-up menu item Control Panel. The program window looks as follows:
Fig.9 PHOTOMOD Control Panel There is a table in the main part of the opened window containing the information about PHOTOMOD storages (Resource storages tab). The storages are displayed as folders selected on different PCs in the network for storing of PHOTOMOD system resources. The icons at the upper part of the window are used to: - Reload storage state. Click the icon to refresh the current state of storages and to show the following data in appropriate columns the table: - identificator name of storage; - state status and location of storage: - local local computer owns the storage - remote remote computer owns the storage - offline no access to the storage and the cache is not available - owner the identifier of PC in local network that hosts the storage; - path the storage folder name with a network or local path; - free space free space in kilobytes on computer-owner of the storage - Add storage. Allows to create or add storage on the local or remote computer. See the chapter 7.2.2 Storages creating - Disconnect storage. Allows to disconnect selected storage. All data remain on the disk and the storage may be connected back (added) later - Edit configuration files. Opens a list of the system initialization files for editing in text editor. The user can edit.ini files only in case of the corresponding requirements from the Racurs technical support department - Install coordinate systems database (See Montage Desktop User Manual) - Start PHOTOMOD System Monitor. Launches the module, and the icon appears in right lower corner of OS Windows Desktop. See the chapter 9 PHOTOMOD System Monitor module

- move resources similarly to the previous operation of resources/projects replacement this button allows to move some resources of the project selected to the chosen storage - shows free disk space in the storages for the selected project (see the chapter 7.2.4 Filling storages while working with the project) - raster control opens new window containing the list of the projects stored in the current storages configuration and their rasters list as well.
(duplicated by hot key F1) - help index opens Resources and their properties, indicated in the right panel table headings (Description, Type, Subtype, Size, Time etc.), could be sorted by mouse click on the header button. Click the resource or project name in the right panel of PHOTOMOD Explorer window to open a list of operations with the resource (see Fig.14). Most of them are the service ones and are not really useful for the end user. Some of these listed below are duplicated in PHOTOMOD Montage Desktop module (for example, export project to file in PHOTOMOD Explorer is identical to project backup in PHOTOMOD Montage Desktop). - placement rules opens an additional window containing placement rules for selected resource - resource placement opens an additional window indicating resource and its storage and whether you can replace it to another connected storage as shown on Fig.14. - delete resource backup copies deletes backup copies of PHOTOMOD resources if they have been created in the project - view in binary opens window to view a resource in binary form - view as DTM resource used for resources containing vector objects - view as image used to display resources with images. Opens a window with an image that can be saved into TIFF or BMP formats and resampled (according to SubSample parameter)
Fig.15 Viewing the image resource
view as INI-file view as text copy copies resource to clipboard paste pastes resource from clipboard (for example to another project) rename renames resource delete deletes resource export exports resource to file import imports resource from file show hidden resources shows/hides hidden resources in PHOTOMOD Explorer window, for example files of PHOTOMOD resources backup and to restore them if needed show additional details turns on an additional columns with information, that also could be sorted by mouse click on the column header: ID resource identifier in PHOTOMOD system Host local computer, the host of the current resource Storage name of the storage where the resource located properties (duplicated by the icon ) opens a window with the resource properties (ID, type, subtype) for viewing and editing (such as the description), see Fig.13.

Moreover, GeoCalculator program allows to view, select, edit and also export/import coordinate system databases, using commands of the Database menu item (Fig.19).
13. PHOTOMOD MSTiff Maker utility
In some cases when you create the projects with big number of images located on different media and which occupy a huge disk space, it is convenient to transfer them into PHOTOMOD MSTiff format even prior to new project creation. This format allows to speed up the access to the initial raster image and also to save disk space. For such transfer use the utility, opened by the following command: Start | Programs | PHOTOMOD | Utilities | PHOTOMOD MSTiff Maker.
Fig.20 MSTiff Maker window In Source images window select the folder with images (upper window) and Tiff files stored there (lower window). You can add/exclude images files from Processing list window using arrow buttons located between the windows. Click these buttons to collect the set of images from different folders/computers to convert them afterwards in PHOTOMOD MSTiff format. The Conversion settings panel allows to set up the following parameters of image conversion: Target folder pop-down list to select the folder for resulting images storing; File names modification to add name prefix (Add prefix field) or suffix (Add suffix) to images names group; Compress % to specify initial images compression level after the conversion, 80% by default; Decompress to allow decompressing of compressed images while converting. If target folder already contains files with the same names, you can overwrite them by new ones turning on the Overwrite existing files option. The buttons Start, Pause, Cancel, Close are used for converting process management and Ready, Current and Total fields to view the process state.
14. PHOTOMOD RasterView utility
If you need to view initial raster images or convert them into formats, which are recognized by PHOTOMOD system, use PHOTOMOD RasterView utility, located in Utilities list (Start | Programs | PHOTOMOD | Utilities | PHOTOMOD RasterView). Click this command to open the following dialogue window.
Fig.21 PHOTOMOD RasterView window First load the initial raster in Tiff or BMP format by pushing the button Open image. To visualize the image in the window mark the View check box. Lens window in right lower corner of the main window shows the part of the image located under marker rectangle. Output images are saved in the following formats: BMP, Tiff, MSTiff, MSTiff with LZW compression, MSTiff with JPEG compression. In the latter case you can set up compression percent of the initial image in Compression quality field. Besides, you can resample the output image pixels by setting the number of rejected pixels in Downscale factor field. For example, if downscale factor is 4, each raw and column of initial image is reduced by a factor of 4. After selecting format and conversion parameters push the Convert button to start the process. PHOTOMOD RasterView is also used for printing of an image opened in the program window, see the chapter 14.1 Image printing.

15.1.2 Merge DGN files

This command is used to merge several DGN v7 files into single one. This may be necessary e.g. for creating summary files for several regions. When this button in the main window of the program is clicked, first an Open dialog is displayed for selecting input files to merge, then a Save as dialog is displayed to enter the name for the resulting merged file.
15.1.3 Fill sheets by polygons
Sometimes during orthophoto creation there arises a requirement for the raster to be exactly limited by a set of polygons (describing e.g. settlement borders), all the rest being filled by the background solid color. In order to achieve this, the Fill sheets by polygons command may be used. When the corresponding button in the main window of the program is clicked, it brings up the same-name dialog.
This dialog allows setting the following parameters: Images files image files to be processed. Acceptable formats include striped TIFF and BMP without compression, georeferenced. File with polygons vector files containing polygons to be used as borders. Acceptable are PHOTOMOD resources (.PHR), DXF, Shapefile (.SHP) formats. Color color to be used as the background fill. Create backup this option causes the program to create a backup copy (with.bak extension) before processing each raster file. Swap X, Y this option causes the X and Y coordinates of border polygons to be swapped before processing. Polygons must be specified in the same coordinate system as the raster georeference data.
15.1.4 Replace font size in MIF/MID files
This command allows to adjust font size (by changing one specified value to another one) in a set of MIF/MID files. When the corresponding button in the main window of the program is clicked, an Open dialog is brought up to select the list of files to be processed, followed by the parameters dialog.
The dialog allows setting the following parameters: Output directory defines the directory where the processed files should be save (the original file names are preserved).
Input parameters group sets width and height of a character in the input file to be searched for and replaced. The units correspond to the basic units in the file (e.g. meters). Output parameters group sets width and height of a character in the output file (to substitute the size of characters matching input parameters). Number of "-" defines the number of - signs in the sheet names. Precision number of signs after decimal separator to be used when writing coordinates.

16. Equipment for stereo measurements
For 3D feature extraction and DTM and contour lines editing in PHOTOMOD StereoDraw, PHOTOMOD StereoVectOr and PHOTOMOD DTM modules three stereomodes are used anaglyph, interlace or page-flipping. Stereo measurements require anaglyph (in anaglyph stereomode) and shutter glasses (in interlace or page-flipping stereomodes), see the details on stereomodes in PHOTOMOD StereoDraw and PHOTOMOD DTM User Manuals. Besides, for effective stereo processing some special equipment and its adjustment described below is needed.

16.1 Stereoglasses

The following types of stereoglasses are tested for working with PHOTOMOD system. Shutter glasses from IBIK, Co, Moscow, Russia (see also www.stereo-pixel.ru and www.ibik.ru for details). IBIK stereo glasses are connected to the computer using sockets of its controller in two places: one socket to com-port, and another one between video adapter and monitors cable. You should also install the glasses driver from Glasses folder (setup_ sfv302.exe file) located on your installation CD-ROM. This folder contains also stctrl.chm file with additional useful information about glasses configuration.
Fig.25 Connecting IBIK glasses You should adjust the driver after its installation. For that start the driver from the Preferences window of PHOTOMOD StereoDraw or DTM modules (menu command Service | Preferences | Stereo,
button) or from OS Windows
menu Start | Programs | Stereo for Windows v.3.0 | Stereo for Windows. Then the is appeared in Windows desktop system tray. Right click on it opens pop-up icon menu where you should select Properties option that calls glasses driver setup dialogue:
Fig.26 Adjustment of IBIK glasses driver Select Properties tab, push the button Autodetect there and after some time the system detects stereo mode settings automatically. Make sure they are as follows: Glasses controller Model should be 3D Max-3 Port should correspond to the PC COM-port where the glasses controller has been installed. Video Chipset should correspond to your video card chipset. If you use page-flipping stereomode in Video Mode field select Default option. Now the page-flipping stereo mode setup is over. Interlaced stereo mode requires different settings: Select Interlaced option in Video Mode field. Video Rate should be Default x 2. On Advanced tab check the Test the display before set a stereo mode option. After that push OK button and adjust your monitor frequency: choose maximal frequency, which does not allow the image to disappear after switching to stereo mode. Turn on stereo mode in drivers menu, popped up after right mouse click on icon in system tray. After turning on of each stereo mode the driver will require confirmation. If you choose too big frequency and the image disappears when stereo mode is on. You should wait for 10 seconds and the initial mode of video card will be restored. When you get an appropriate frequency, un-mark the option Test the display before set a stereo mode on Advanced tab, after that the driver will not ask for confirmation at stereo mode start. 3DS-GM shutter glasses with 3DS-PC3 controller provided by STEL Corporation (Russia). Controller is connected between video card connector and monitor cable. Glasses are connected to operating unit of controller. The glasses do not require drivers' installation, it is enough to press the button OU/PF on operating unit. At that light diode should flash by green light. This type of glasses is used only for page-flipping stereo mode. NuVision shutter glasses provided by MacNaughton.Inc (see www.nuvision3d.com for details). There are two possible types of NuVision glasses: - NuVision 60GX is used for video cards with special plug to connect the glasses. The glasses kit includes the IR-emitter and glasses. - NuVision 60GX-NSR is used for video cards that do not have the glasses connection plug. The kit in this case consists of IR-emitter, glasses and the synchronization box.

Fig.27 NuVision 60GX-NSR glasses kit Beside the shutter glasses you can use simple anaglyph glasses with red and blue filters. Anaglyph stereomode requires no special equipment but it is not completely good for working with color images. Another disadvantage is that the picture gets a bit darker when viewing with filters.

Fig.28 Anaglyph glasses

16.2 Video cards

For IBIK glasses work

Video cards Matrox G200, G400, G450, G550 ATI Radeon Mach64, Rage, RageII, Rage128 Intel i740, i810, i815 Nvidia GeForce 2,3,4 Nvidia Quadro Mode Interlace Pageflipping yes no Interlace mode configuration standard work using the IBIK driver
standard work using the IBIK driver

3D labs Wildcat

Interlace mode is turned On by using the video card driver. Using IBIK driver in Default stereo mode turns On the glasses.
For NuVision 60GX-NSR glasses work
Video cards Matrox G200, G400, G450, G550 ATI Radeon Mach64 Rage, RageII, Rage128 Intel i740, i810, i815 Nvidia GeForce 2,3,4 Nvidia Quadro 3D labs Wildcat Mode Interlace Pageflipping yes/no no Interlace mode configuration Interlace mode is turned On using video driver on those video cards where it is possible. The button on the synchronization box turns On the glasses.

no yes

yes yes
Interlace mode is turned On by the video card driver. The button on the synchronization box turns On the glasses.
For NuVision 60GX glasses work
Video cards Nvidia QuadroXGL QuadroXGL QuadroXGL QuadroXGL QuadroXGL QuadroXGL QuadroXGL Quadro FX 330 Quadro FX 500 Quadro FX 1000 Quadro FX 2000 3D labs Wildcat VP760 Wildcat VP870 Wildcat VP970 Wildcat 4105 Wildcat 4110 Wildcat 4210 Wildcat II 5000 Wildcat II 5110 Wildcat III 6110 Wildcat III 6210 Wildcat Wildcat Interlace no Mode Page-flipping yes Interlace mode configuration
Interlace mode is turned On by the video card driver. Glasses are On automatically
PHOTOMOD system also supports ATI video cards (fireGL series) for work in page-flipping. Note. For working in page-flipping mode you need a video card supporting quadbuffering mode and its driver must support Open GL 1.2 and higher standard. For working in interlace mode the video card just should support interlace mode
In case of using IBIK glasses you should install driver and set up the glasses in Default mode (see the chapter 15.1 Stereoglasses). If using NuVision 60GX glasses the IR-emitter is connected to the video card and the glasses are On automatically when switching to the stereomode. The NuVision 60GX-NSR glasses are turned On by pressing the button on the synchronization box. Note. When purchasing video card, make sure that its interface (AGP or PCI Express) is compatible with interface of the motherboard installed on your computer Below there is a list of some recommended video cards for work in page-flipping stereo mode. Nvidia Quadro2 Nvidia QuadroXGL Nvidia QuadroXGL Nvidia QuadroXGL Nvidia QuadroXGL Nvidia QuadroXGL Nvidia QuadroXGL Nvidia QuadroXGL Nvidia Quadro FX 330 (PCI Express interface) Nvidia Quadro FX 500 Nvidia Quadro FX 540 (PCI Express interface) Nvidia Quadro FX 1000 Nvidia Quadro FX 1300 (PCI Express interface) Nvidia Quadro FX 1500 (PCI Express interface) Nvidia Quadro FX 2000 3D labs Wildcat VP760 3D labs Wildcat VP870 3D labs Wildcat VP970 3D labs Wildcat 4105 3D labs Wildcat 4110 3D labs Wildcat 4210 3D labs Wildcat II 5000 3D labs Wildcat II 5110 3D labs Wildcat III 6110 3D labs Wildcat III 6210 3D labs Wildcat 3D labs Wildcat Note. Graphic cards Nvidia of GeForce series do not support page-flipping stereo mode Actually the list of video cards in the table is not complete. However the out-of-list video card may need some adjustment and testing.

3D Mouse Z (S1-Z or S2-Z) in Used mice field, see the chapter 15.4 Mice and hand wheels adjustment for stereo processing.
Fig.45 Stealth 3D Mouse S1-Z setup in Mouse configuration window
Fig.46 Stealth 3D Mouse S2-Z setup in Mouse configuration window
Use Standard mouse button actions assignment panel to the right to assign actions of the standard mouse buttons to the Stealth 3D Mouse-Z. Select the Stealth 3D Mouse-Z button in Button column (button names and their location are shown on leftward picture), and in the appropriate cell of Assignment column select necessary button of usual mouse by double click in the following way. The first double click will assign left button click (symbol L will be shown in the Assignment cell), the next double click will assign left button click (symbol R will be shown in the Assignment cell), the next one middle button click (symbol M). Such marker move assigned to Stealth 3D Mouse-Z will be valid for all applications on your PC, while PHOTOMOD System Monitor is running. After that push Apply and OK buttons and open Macro editor in Mouse setup window, if you need to create new macro, see the chapter 15.4.6 Macro editor. Then return to Mouse setup window and assign new or existing macro to necessary button or button combination, by selecting it in Available buttons list (choose button combination by mouse with pressed Ctrl or Shift keys), see the chapter 15.4.1 Three and five button mice.
Fig.47 Stealth 3D Mouse S2-Z buttons setup To assign new macro to chosen mouse button, select the action in Macros list, then select mouse button in the Available buttons list, and assign the action to the button by pushing the icon push the icon Add binding (or by double mouse click). If you need to cancel the assignment, Delete binding.
Note. Standard mouse button actions can not be assigned to the buttons of Stealth 3D Mouse When all necessary actions are assigned to the mouse buttons, you can save this actions configuration to the default driver (by the button Save as). Save) or to the new one (by the button
16.4.5 Hand wheels and foot pedals 16.4.5.1 Immersion compatible hand wheels and foot pedals

Hand wheels and foot pedals (produced by GeoSystem Company, Ukraine, www.vingeo.com) are used for 3D photogrammetric images processing in PHOTOMOD system. Equipment delivery set includes right and left hand wheels (to perform marker move in plane), foot wheel (to move marker in height) and three pedals (which are assigned to mouse buttons actions, selected by user). These devices are connected to the PC via Immersion Interface box (see hardware installation details in equipment User Manual). After devices installation to your PC, turn PC on and run PHOTOMOD System Monitor module. Then open the window with mouse settings (menu command Service | Mouse setup in PHOTOMOD Montage Desktop module), push the Device setup button and select Immersion compatible hand wheels/foot pedals in Used mice field, see the chapter 15.4 Mice and hand wheels adjustment for stereo processing. Then in Device parameters panel select its COM-port and baud rate. You can adjust hand wheels sensitivity in XY axes using XY plane sensitivity slider, and also foot wheel movement sensitivity, which operates marker in Z axis (using Z sensitivity slider). If you need to re-assign X and Y axes to left and right hand wheels, check the option Swap X and Y. And if you need to invert movement of marker by right, left or foot wheels, check an appropriate option Invert X, Y or Z motion.
Fig.48 Immersion compatible devices adjustment in Mouse configuration window
After that push Apply and OK buttons and the following picture appears in Mouse setup window.
Fig.49 Setup of Immersion compatible foot pedals This window contains list of macros existing in default driver or created/edited by the user in Macro editor, see the chapter 15.4.6 Macro editor. The rightmost window consists of two tabs, one of which allows to setup standard mouse buttons (see the chapter 15.4.1 Three and five button mice), and the second one (Immersion compatible hand wheels/foot pedals) markers actions after pressing each of three pedals. To assign new macro or existing to chosen pedal, select the action in Macros list, then select pedal in the Available buttons list, and assign the action to the pedal by pushing the icon Add binding (or by double mouse click). If you need to cancel the assignment, Delete binding.

push the icon

16.4.6 Macro editor

PHOTOMOD system includes the set of macro commands for mouse, which could be edited up to user needs and then assign the commands for chosen mouse buttons or foot pedals, if such special photogrammetric equipment is used for images stereo processing. To open the window with macro list, push the button in the Mouse setup window (see the chapter 15.4 Mice and hand wheels adjustment for stereo processing, Fig.3), after that Macro editor window appears. In the left part of the window there is a list of macro commands that are included into mouse driver by default.
Fig.52 Macro editor window This list contains the following macros: Macro name 3D snapping Activate vertex Action description Snap cursor to the objects V vertex Activate objects vertex Alt-S Keys Actions order in macro Press V Release V Press Alt Press S Release S Release Alt Press 2 Release 2 Press 1 Release 1 Press 3 Release 3 Press Esc Release Esc Press Space Release Space Press Del Release Del Press Del Press S Release S Release Del Press Ctrl Press left mouse button Release left mouse button Release Ctrl
BCG down BCG select BCG up Cancel selection Correlate Delete Delete segment
Parameter decreasing (brightness, contrast or gamma) Selecting and adjusting of brightness, contrast and gamma Parameter increasing (brightness, contrast or gamma) Cancel selection Correlate Delete Delete segment

3 Esc Space Del Del-S

Drag by mouse

Ctrl-Left mouse button

Insert before Insert before active vertex active vertex Left Left mouse button click

Optimize TIN

Turn on pan mode

Parallax=0 Pop-up menu

Nulling the parallax Show pop-up menu

Rebuild contours

Rebuild contour lines

Restore cancelled action

Select object Select vertex
Select object Select objects vertex

Snap to ground Tab Undo

Snap cursor to ground level Close additional windows Cancel action
Vertex to marker Zoom 1:1
Move vertex to marker position 1:1 zoom
Press Enter Release Enter Ctrl-Ins Press Ctrl Press Ins Release Ins Release Ctrl Left mouse Press left mouse button button Release left mouse button Ctrl-O Press Ctrl Press O Release O Release Ctrl Alt-Left mouse Press Alt button Press left mouse button Release left mouse button Release Alt F2 Press F2 Release F2 right mouse Press right mouse button button Release right mouse button Ctrl-L Press Ctrl Press L Release L Release Ctrl Alt-ShiftPress Alt Backspace Press Shift Press Backspace Release Backspace Release Shift Release Alt S Press S Release S Shift-S Press Shift Press S Release S Release Shift T Press T Release T Tab Press Tab Release Tab Alt-Backspace Press Alt Press Backspace Release Backspace Release Alt J Press J Release J Alt-1 Press Alt Press 1

17.2 Initial setup

Before performing initial setup of the PHOTOMOD system for distributed processing, the control folder must be created. It has to be an empty folder available for reading and writing from all the computers planned to be using it. Note. During normal operation, auxiliary files are created in the control folder. It is not recommended to edit them manually as this may lead to failures in processing. Setting up a workstation for participating in the distributed processing is performed by executing the menu command Distributed processing | Parameters in the context menu of the PHOTOMOD System Monitor, invoked by right-clicking the ball icon in the Windows system tray.
This command brings up the Distributed processing setup dialog which allows to set up the following parameters: Folder for storing control data field for specifying the control folder, see 16.1 General information. Maximum number of simultaneous processes by default this number is equal to number of CPUs or cores (for multi-core CPUs) of the computer. Generally, it is not desirable to set this value higher than the mentioned default value (as this will not lead to performance increase, on the contrary, the execution will slow down); if it is planned to use the computer for other purposes in parallel with distributed processing, the value may be stepped down Use this computer for distributed processing when this option is checked and tasks appear in the control folder, the specified number of execution processes are launched to process the tasks. When this option is unchecked, it is still possible to monitor other computers in the group via the Distributed processing | State command (see 16.3 Monitoring distributed processing).
17.3 Monitoring distributed processing
After the initial setup is complete, distributed processing state is monitored by the command Distributed processing | State in the context menu of the PHOTOMOD System Monitor, invoked by right-clicking the ball icon in the Windows system tray.
This command brings up the State monitoring window which displays the tasks queue and load of the computers involved in processing, and allows altering the execution of tasks. This window may also be called by double-clicking on the ball icon in the tray. The window is split in two groupboxes: the upper one (Tasks in queue) contains the table with the tasks list and a toolbar for controlling tasks; the lower one (Computers) contains the table with the list of computers in the processing group, and the corresponding toolbar. The windows is automatically refreshed every several seconds; to disable refreshing, uncheck the Auto refresh checkbox in the bottom panel. This renders available the Refresh ( ) buttons in the toolbars which refresh the corresponding table each.

17.3.1 Tasks in queue

The Tasks in queue groupbox contains the toolbar and the summary table of the tasks. Each tasks has the following properties: ID a unique identifier of a task (is preserved when the task is completed and moved to the finished tasks list, see 16.3.3 Finished tasks). State task state: waiting to be executed, suspended, running (in this case the progress is shown). Pripority task priority (an integer number; the higher the number, the higher the priority; tasks with the highest priority are executed first). Name text string describing the task. For orthomosaic creation tasks PHOTOMOD Mosaic project name with the ordinal number of the task in the project. Type currently only one task type is available - mosaic

phototriangulation: see aerial triangulation pixel: the smallest element of a raster that can be individually processed. Pixel size defines spatial image resolution. pixel coordinates: coordinate system represented by X and Y image pixel coordinates in plane and the parallax by Z axis point: a 3D vector object defined in space by X, Y and Z coordinates polygon: a closed polyline polyline: a 3D vector object defined by a sequence of spatial points (vertices) with known X, Y, Z coordinates, connected by straight lines (segments). pre-region: arbitrary polygons drawn in PHOTOMOD Montage Desktop module over the adjusted block of images in order to mark some areas of interest. Pre-regions could be used for DEM creation on each stereopair. principal point: the point in the image where main optical axis intersects with image plane project: PHOTOMOD system integrated data structure for complete digital photogrammetric processing. PHOTOMOD project consists of resources. projection: see map projection. projection center: a point in the image coordinate system defined by the x and y coordinates of the principal point and the focal length of the camera. after the aerial triangulation, a point in the ground coordinate system that defines the camera's position relative to the ground. Also known as perspective center In central projection it is the point of intersection of projecting rays. Projection center coordinates may be obtained both by external measurements (GPS, for instance) and by aerial triangulation pushbroom scanner: a remote sensing system that build up an image using a CCD-linear array of charged coupled devices or CCD's that record each element of a scan line simultaneously without the use of electromechanical components. For example, the HRV sensor onboard the SPOT satellite uses this method. Pushbroom scanner also referred to as an along-track scanner, which does not use rotating mirrors. The sensor detectors in a pushbroom scanner are lined up in a row called a linear array. Instead of sweeping from side to side as the sensor system moves forward, the one dimensional sensor
array captures the entire scan line at once like a pushbroom would. Some recent scanners referred to as step stare scanners contain two-dimensional arrays in rows and columns for each band. Pushbroom scanners are lighter, smaller and less complex because of fewer moving parts than whiskbroom scanners. Also they have better radiometric and spatial resolution. A major disadvantage of pushbroom scanners is the calibration required for a large number of detectors that make up the sensor system. PHOTOMOD system allows to process pushbroom scanned images. See also whiskbroom scanner. Q R raster: a discrete, digital representation of aerial or satellite image used in photogrammetric processing. real coordinates: see geodetic coordinates reference file: a file of 3D vector objects loaded in read-only mode for viewing when editing another vector file. region of interest: an image portion to be orthorectified while the orthomosaicking. Region of interest is defined by a cutline. regular TIN: a TIN creation algorithm that uses correlator to calculate Z value in each node of predefined rectangular grid. If the correlator fails (the correlation coefficient is less than the selected threshold value) in some node the corresponding Z value is calculated by the interpolation of the neighboring nodes. See also adaptive TIN, smooth TIN, TIN by vectors. relative orientation: the recovery of the position and orientation of one image relative to another from correspondences between five or more pairs of tie points. Relative orientation process computes the relative orientation parameters to define the relative position of the pair of images. relative orientation parameters: parameters calculated in the relative orientation process to define the relative position and orientation of two images in the stereopair. Relative orientation parameters include two angles (, ) for the left image and three angles (, , ) for the right image resource: an integrated, organized unit of data stored in PHOTOMOD project. Resources are images, TINs, 3D vectors, contours etc. right-handed coordinate system: a coordinate system that has an X axis directed to the east and Y axis directed to the north. See also left-handed coordinate system.