Chunk Data - Point Grey Gazelle GZL-CL-22C5M-C Technical Reference

Point Grey Gazelle Technical Reference
6.6

Chunk Data

The camera provides a feature that allows image information and camera settings, such as checksum, frame counter,
region of interest (ROI) and other settings, to be embedded in images. When this feature is enabled, the last pixels of the
last line in an image are replaced with 'chunk data' that contain binary values for the information requested. The size of
each chunk depends on the data item. Refer to the table below for a list of items in the order they are embedded and
the number of pixels each item comprises. In 10-bit per pixel mode, the two left-most bits of the pixel are padded with
zeros.
Value (Information
Item)
htroi3
stroi3
htroi2
stroi2
htroi1
stroi1
htroi0
stroi0
width
offsetx
blacklevel
gain
exposure
horizline
framecounter
checksum
Revised 10/31/2013
Copyright ©2011-2013 Point Grey Research Inc.
Table 6.1: Chunk data information types, order and size
Pixels
2
2
2
The vertical offset (stroi) and height (htroi) of regions of interest (ROI) 0, 1, 2 and 3 (if
2
configured) of the image. For more information, see
2
data on the first four ROIs can be embedded in chunk data.
2
2
2
2
The width and horizontal offset of all regions of interest (ROIs)of the image. See
Specifying Regions of
2
2 See Black Level
1 See Gain.
3 See Exposure.
The line number of the horizontal line artifact. For more information, see
2
Artifact.
The frame number since the onset of free- running or synchronized exposure. For more
2
information, see Image Acquisition
A checksum computed as the sum of all previous bytes in the image. This value can be
compared with a user-generated checksum on the transmitted image to determine if the
image was corrupted during transmission.
8
Checksum is specified using separate syntax (see below).
Description
Interest.
6 Imaging Parameters
Specifying Regions of Interest. Only
Horizontal Line
47