Kraków, 5-05-1998

Video Stereo Digitizer

1. Introduction

The AGH Video Stereo Digitizer (VSD) it is a stereoplotter adopted for production of vectorial maps with the use of the pairs of digital black and white or color photogrammetric images (stereopairs or orthostereopairs). The VSD can accept CDD images or scanner images or scanned satellite, aerial or terrestrial photograms.

The VSD plotter can be used for evaluation of topographic maps, and can also serve very well or recording of plants of historic moments of architecture or arts as well as the archaeological plans mapping. Plotted details of the pair of digital images displayed on the PC - SVGA screen are selected by the human operator with the use two cursors animated by a mouse. Selected points can be connected by the polygon line. Irregular curves are plotted (digitized) by recording of cursor trajectory. The polygons and trajectories are superimposed over the half tone images on the PC screen in a chosen color. To each color of displayed numerical map an individual layer is assigned in the computer memory (data base) in the DXF-code or binary code.

The AGH Video Stereo Digitizer can be used also as mono or stereo comparator for the measurement of the digital images with the accuracy of the screen pixel fraction; the accuracy depends on the digital image zooming coefficient.


2. Digital images

Program accepts the following formats for digital images:

1. TIFF monochromatic non-compressed (max. 256 half tone steps)

2. Indexed Color TIFF with the palette 256 colors.

Only 248 positions in the palette will be used for digital image however, because remaining 8 colors is reserved for numerical map displaying on the screen.

3. The monochromatic pixel map format:

Monochromatic format organized as a simple stream of pixels (max. 256 half tone steps). For this format the length of line and image offset must be defined.


3. Organization of the disk memory

Before starting VSD program few directories devoted to the VSD program have to be created. Digital photographs can be stored in one or more directories. File ProjectName.PKT (described below) must be placed in the pre prepared directory which will be declared by name at the program initiation as the one accompanying restitution and plotting.

Existing vectorial maps in DXF format can be included to the project by transformation DXF format to the ABS format (specific VSD format). For such transformation special program DXF_ABS.EXE is provided.

Directory accompanying restitution and plotting contain also files produced by VSD program:

ProjectName.ETK - histogram and other information's about photographs

ProjectName.CFG - parameter of the project, it is: stereopaire or a single photo

ProjectName.S?? - reduced size pair of photos or single photo to select the working frames

ProjectName.LU - files containing coordinates of surveyed points- binary file

ProjectName.LU1 - as ProjectName.LU, but for the single photograph - binary file

ProjectName.OR - as ProjectName.LU1 or .ProjectName.LU, but ASCII file


_OR_REL.WYN - temporary files containing results of

_OR_ABS.WYN - subsequent steps of stereopair orientation


ProjectName.PKT - preprepared ASCII data:

- No. and coordinates of fiducials and/or reseau grid

- No. and field coordinates of control points

ProjectName.ADP - parameters of distortion (by method of ORIENT)

Name.MAP - ASCII file of map lines in the image coordinates (an internal format)

Name.ABS - Binary file map lines in the field coordinates (an internal data format)

Name.DXF - file Name.ABS in the DXF format

Name.PNT - ASCII file of 3D or 2D points in the field coordinates ( no. x y [z] )

Attention. The last 3 files can be of the project name, but can bear any other name to enable several plotting files from the same pair of pictures.


4. Starting of the program

Program can be started by keying VSD L or VSD H . VSD L calls for screen resolution 800x600, VSD H calls for screen resolution 1024 x 748 pixels, and VSD S - for 1280 x 1024 pixels.

If you want to omit the title screen you must press key "escape" just after starting.

At the beginning program will ask about:

- path to project directory

- project name

- names of digital-photo files or names with paths to the photo files, but particularly in case when the photo-files are located in other directories then default for project

- selection of a image portions on the supporting reduced-resolution pictures.

A green rectangle can be shifted by the operator simultaneously both pictures or independently on left or right pictures, switched by TAB.

To create 1:1 resolution picture on the screen the left mouse button or ENTER key must be used.


5. Orientation and plotting

- Interior orientation:

- survey of 2 or more fiducial marks [I]. To use for calculation the coordinates from

file ProjectName.PKT with the calibration results use Point Number and [INS]

- calculation of transformation parameters [F5] (calculation can by performed here, or

after all the survey for relative and/or absolute orientation is completed)

- Relative orientation

- survey of 5 or more points selected by key [H]

Here you can use supporting semi-automatic correlation [F9]

- calculation of relative orientation elements [F6] (with entering elements of interior orientation and coefficients radial/tangential distortion )


- Absolute orientation

- survey of 3 or more pass-points (all points must have xyz coordinates)

To use coordinates from the file ProjectName.PKT insert Point Number and press [INS]

- calculation of absolute orientation elements [F7]



All the above operations were performed in the stereocomparator mode (with the use [TAB] and [1]).

To erase surveyed point use the number of point with minus.

To erase group of surveyed points use the number zero.

- Stereoplotter mode

- to activate the stereoplotter mode use [F8] (calculation of DLT coefficients)

- or read DLT coefficients from the file ProjectName.DLT [Alt F8]

- Plotting

For plotting use the polygon line [P]...[P]...[K] or trajectory [T]...[K]. You can correct mistakes [U] or [TU]. During plotting you can visualize existing vectorial map [E], and you can plot simultaneously 7 layers (colors [B]) to update the existing vectorial map or to produce your own file.

There exist 3 plotting supporting routines:

- semiautomatic correlation [F9]

- automatic tying vector end to existing points of polygon (few pixels correction) [D]

- automatic designing of line orthogonal to existing vector [N], [Alt N]


6. Program installation

Basically it would be enough to create a special directory under name VSD, and to copy to that directory all the files from the installation diskette.

It would be advantageous, however, to add to the set of system paths in the AUTOEXEC.BAT file also the path to the VSD directory:

PATH = . . . . . . . . . . . . . . .. ; C:\VSD

Instead of the above you can copy VSD.BAT file to one of the directories already existing in the AUTOEXEC.BAT path.

Extended RAM memory is employed by the VSD - system, and therefore it must use (independly installed) HIMEM.SYS driver and has to have adequate RAM memory available (1408 Kb for resolution 800*600, 2048 for resolution 1024*768, and 3328 Kb for resolution 1280*1024 pixels on the screen). To do that, you should add to the CONFIG.SYS file at least:


FILES = 40

In case of lack of adequate extended memory one can try to use an /d calling parameter.

VSD uses a 3-button mouse, and therefore also the mouse driver must be installed before VSD program initiation.

VSD - program works in the VESA standard and requires the adequate graphic VESA standard card or additional program that emulates the VESA standard.

We wish you good luck with the installation.


7. Menu and active keys

The system can be controlled directly by active-keys or via multi-level menu.

Hot Abbr. Meaning


Image Selection of the image portion and the scale of ____ visualization

V select selection of another image portion for visualization

- submenu: [E] - visualization of recorded vectorial map

[*] - visualization of recorded points

[Tab], [1] - similarly for cursor moving

C center cursor together with image shifting to the screen centers

Z zoom image enlarging two times

M zoom image reducing two times

Alt Z zoom selection of coefficient for zooming (negative - reducing)

Ctrl Z magnifier measuring magnifier

R refresh refresh screen and redraw vectorial map

Alt R restart back to the photo 1:1 scale

Ctrl R hide hide the raster background

0 (zero) go_to image centering to the point indicated by coordinates entered from

keyboard or by number and key INS from *.PKT file

F filter edge sharpening on the full screen

Y Y-parall image y-parallax clearing at the stereocomparator mode

O look a look on the photo at 1:1 scale

Map Visualization of the vectorial map on the raster image___

E import import or erase vectorial map (erasing for name = SPACE )

Alt U erase erase of current vector map

Ctrl E map_2D import 2D vectorial map and set Z coordinate of all vectors to average elevation of control points

Ctrl D elevation change elevation of 2D vectorial map to current elevation of cursor

Alt E hide hide / show vectorial map

Alt B list viewing the list of layers with attributes

Ctrl B layer selection the layer by indicated vector

Alt J points_J import points of J-group from ASCII file *.PNT

F12 save save vectorial map to *.MAP file

plotting Plotting of the vectors of the map____________________

P polygon coordinates recording for the first or next points of polygon

B layers selection or adding or modification of the thematic layers

K end coordinates recording for the last point of polygon

D tie-up tie the line to the existing indicated point J or end of vector (snapping)

. (point) connect designing of a line connected to a point indicated on the vector

(crossing of 2 vectors)

N ortho designing of a line orthogonal to the vector

Alt N ortho designing of a (leveled) line orthogonal to the vector

T trajectory initiation of recording of cursor trajectory

Alt T step entering a step of recording of cursor trajectory

U erase erasing a pointed vector of polygon

Bcksp erase erasing the last recorded vector

TU erase erasing the end part of trajectory

J point recording of point


cursor Selection of the cursor and control of cursor________

X shape cursor shape selection

L coLor cursor color selection

SPACE point cursor shape reduced to the pixel-size

F1 lower lowering of the cursor along plumb line

F2 upper raising up the cursor along plumb line

reference Image orientation and the reference coord. systems def._

I record_I fiducial marks recording (INS - enter coordinates from *.PKT file)

H record_H recording points for relative orientation

G record_G recording points for absolute orientation (INS - coord. from *.PKT)

F5 fiducials determination of transformation to the fiducials or transformation to reference coord.system for mode of mono-image

F6 relatori calculation of relative orientation elements

F7 absori calculation of absolute orientation elements

F8 dlt activation of DLT

F9 autocorrel semi-automatic stereo-correlation

F4 dlt calculation of DLT for non-metrics photos

F3 net linear net adjustment for single image

' coord change of the coordinate system definition for single image

Alt F7 absori calculation of selected elements of multistage absolute orientation

Alt G passfile reading new list of field points from *.PKT file

Alt F8 DLT reading DLT coefficients from *.DLT file

control Switching of mode of the cursor control________

- reduce reduce the cursor speed

+ increase increase the cursor speed

Alt gray+ step entering a step of cursor moving

TAB cntrl_1 blocking of left/right cursor

1 cntrl_2 simultaneous control of the pare of cursors

A stcmp on / off fast changing of elevation

Alt A mode switch of mode of fast changing of elevation

S control floating mark controls modes

F (blue) - photogrammetric (field) coord.syst.

G (yellow) - object (field) coord.syst. (in which all pass points where defined)

M (magenta) - 3D fiducial coord.syst. - left camera

I (white) - above for nonmetric images

screen Changing status of the screen_______________________

W display coordinates display switch

white - 2D image coord.syst. (in pixels)

cyan - 2D fiducial coord.syst. (in mm)

magenta - 3D fiducial coord.syst. -left camera

yellow - 3D object (field) coord.syst.

blue - 3D photogrammetric (field) coord.syst.

* mark visualization of recorded points on the screen (on/off )

Alt 8 (*) numbers visualization of point numbers

Alt F2 slide screen registration in file *.TIF, *.BMP or *.PCX

Alt F1 ram rapport of computer RAM and status VSD


others Miscellaneous_______ ___________ ___ ___

\ length calculation of pointed vector length

= area calculation of pointed polygon area

menu Calling of the VSD function__________________________

Escape call for the menu /erase menu, call multilevel text menu

INS menu shift menu to the screen top/bottom

F10 menu show graphics menu operational for plotting (experimental)

Alt Q DOS temporary exit to DOS

Q Q-system saving files of vectorial maps followed by quitting the VSD system