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E UT te TOM quom "CCD IMAGES
CAPTURE OPTIONS
Picture:
Camera: 1 2
NONE
CAMI
CAM2
CAM3
CAM4
Stopbefore [7] ET T1
capture
zm
Film pcs.
Delay
File Edit View Options Camera Window About
Figure 2. Window with four single images from testfield
The images 2 and 4 are zoomed out.
This frame grabber card makes it possible to perform
many unable operations, the most essential for its work
are as follows :
e continuous acquisition of generated analog images
from one CCD camera, in the so called mode "Live
video", without their digital storing,
e continuous acquisition of a certain number of images
having defined recording interval, in the "Film"
mode, from maximum 4 cameras, together with their
automatic storage; for successive images created
files get extension *.cO1, *cO2 etc.,
automatic acquisition of 4 successive images
sequence from single camera or parallel single
images from max. 4 cameras,
conversion of the recorded images to digital form,
transmission of the images to operational memory
RAM or their storage on HD or FD; the files obtain
the extension *.ccd,
e display on the screen of single images or 4
Successive images from single cameras or single
images from not more then 4 cameras,
zooming of image parts,
processing of digital images, comprising :
correction of quality image trough one of 4 contrast
enhancement methods
contouring of the image with one of 4 extraction
methods,
e measurement of point coordinates on the screen in
interactive mode with automatic assignment of
numbers to successive points; there is a possibility
of point position correction or their cancelling,
© creation of files containing numbers and coordinates
of reference point in the screen pixel coordinate
System; they are written down in ASCII codes, with
extension *.rp,
targets with dialog-box ( image in normal case).
515
e conversion of files — *.ccd with recorded digital
images to the *.bmp format.
The system produces standard bit-map format files to
store the images on the hard disk. This makes it
possible to export the video images to other
MS WINDOWS applications. The sequence of the
images are stacked in single file in order to diminish
their numbers in the current directory. In real-time
mode, because of storing images in the computer
memory, the number of acquired images is limited.
Practically, for today's computers with some
megabytes of memory, this problem does not exist.
3.4 Image processing procedures
In the module of digital processing, admitted range of
processing techniques comprises procedures enabling
image quality improvement and contouring of edges if
the objects contained in digital image. Methods of
image quality improvement make it possible to correct
deformations of the image caused by, among others,
non-proper lighting of the object, badly set sharpness,
additional noise occurring, etc. These are contrast
enhancement methods :
e histogram equalization method,
e linear histogram stretching.
The second category of this range are operators :
e non-linear processing - squaring,
e non-linear processing - rooting.
Detection of object edges in the image allows to obtain
the image in the form of distinguished borders of the
objects being in the scene (non-continuous change of
image attributes). It enables logical interpretation of the
image. Applied contour extraction methods comprise :
® gradient method using 1-st order neighbourhood,
e gradient method using 2-nd order neighbourhood,
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996
