Vecow VSM-200 User Manual page 28

©Vecow VSM-200 Video Capture Card Series User Manual
Motion
The motion detection threshold is an 8-bit programmable value
used to determine the presence of motion. This value represents
a minimum delta between scaled block average luma values to
indicate motion within a block. The motion number of blocks
detected threshold is an 8-bit programmable register field that
controls how many blocks must detect motion before the frame
comparison indicates motion detected to the host and external
interrupts.
No Motion
The still image threshold is an 8-bit programmable value used to
determine a non-changing image. This value represents a maximum
delta between scaled block average luma values to indicate a
constant image within a block. The still number of blocks detected
threshold register field indicates how many of the 192 grid regions
detected a still image. The still frame threshold register field controls
how many blocks per frame must detect a still image to cause the
still image frame counter to increment. The still frame threshold
field controls how many consecutive still frames are required before
the interrupt is asserted.
Black/Low Light & Black and white detection is performed on each field/frame that is
used for motion detection. In order to detect the black and white,
White / Day Light
the following thresholds and limits are used:
i. For every pixel of the field indicated by the top_bot_field_sel
register field of the MDET_{x}_CTRL register, if the luma value is
less than the black threshold, the black detection counter will be
incremented.
ii. If the luma value is greater than the white threshold, the white
detection counter will be incremented.
iii. If, at the end of the field, the black detection counter is greater
than the black field limit value, a black detection will be signaled for
that channel.
iiii. If, at the end of the field, the white detection counter is greater
than the white field limit value, a white detection will be signaled
for that channel. The black and white detection counters will be
reset before the beginning of the next field for detection.
Software Application
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