Phytec eGrabber-4plus, Руководство по оборудованию

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eGrabber-4plus
54 
PHYTEC Meßtechnik GmbH 2004 L-608e_4
Please note, that the image will be displayed distorted (stretched or
shrunk) if the 4:3 ratio is not adhered to. (This width to height ratio
arises due to television standards).
The TV Format button prevents image distortion by automatically
adhering to the 4:3 ratio (width/height relationship). For example, if
given the number of pixels, the number of rows is automatically
calculated with the 4:3 ratio.
The Window Size button can be used to extract a section of the image,
and display this section instead if the whole picture on the monitor.
This section can be smaller than the viewing field of a camera. If the
entire digitized field is to be displayed, then checkmark the
Image=Window box.
The Window Size does not distort the image geometry because it is not
a scaled section, rather then a cut out section.
Note:
Please note that scaling and cutting section processing is run in real
time in the Grabber. The Grabber stores the image as it is displayed on
the monitor. This is very beneficial because the CPU is not needed for
this function.
A brief explanation of similar television technology will lead to a
better understanding of the buttons field1, field2, full frame, and field
aligned.
A television image (normal video signal) is made up of two interlaced
images, so called half frames (fields) (see Figure 28). These half
frames (fields) are consecutively generated in a similar fashion and
then displayed on a screen (i.e. television).
The interlacing of the images reduces the flickering that can occur
with TV images.