CHEETAH Hardware User’s Manual
Imperx, Inc.
Rev 1.7
6421 Congress Ave.
8/26/2016
Boca Raton, FL 33487
+1 (561) 989-0006
49 of 121
output mode, communication rate, etc. are properly configured. Please note that the
test image patterns do not exercise and verify the image sensor functionality.
The following test images are available:
-
H Ramp Still
– displays a stationary horizontal ramp image
-
V Ramp Still
– displays a stationary vertical ramp image
-
H Ramp Move
– displays a moving horizontal ramp image
-
V Ramp Move
– displays a moving vertical ramp image
-
Cross-hairs
– displays a cross-hair in the absolute center of the image. A live
image is superimposed under the cross-hair pattern. (Cross-hair has a thickness
of 2 pixels)
2.12
WHITE BALANCE AND COLOR CONVERSION
2.12.1 White Balance Correction
The color representation in the image depends on the color temperature of the light
source and CHEETAH has a built-in algorithm to compensate for this effect. When
white balance correction is enabled, the camera collects the luminance data for each
of the primary colors R, G and B, analyzes it, and adjusts the color setting in order to
preserve the original colors and make white objects appear white. The algorithm
collects data from the entire image, and can work in four different modes – “Off”,
“Once”, “AWB Tracking” and “Manual”. When set to “Off”, no color correction is
performed. When set to “Once” the camera analyzes one image frame, calculates
only one set correction coefficients, and all subsequent frames are corrected with this
set of coefficients. When set to “Manual” the camera uses the correction coefficients
as entered from the user. In “Tracking” mode the camera analyzes every frame, a set
of correction coefficients are derived for each frame and applied to the next frame.
When “Auto-White Balance (AWB) Tracking” mode is selected, the user can select
5 tracking speeds from slow to fastest.
2.13
TRANSFER FUNCTION CORRECTION
– USER LUT
The user defined LUT (Lookup Table) feature allows the user to modify and transform the
original video data into any arbitrary value – Figure 25. Any 12-bit value can be
transformed into any other 12-bit value. The camera supports two separate lookup tables,
each consisting of 4096 entries, with each entry being 12 bits wide. The first LUT is factory
programmed with a standard Gamma 0.45. The second LUT is not pre-programmed in the