CHEETAH Hardware User’s Manual
Imperx, Inc.
Rev. 6.2
6421 Congress Ave.
7/7/2015
Boca Raton, FL 33487
+1 (561) 989-0006
68 of 152
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 (2000 x
1500). A live image is superimposed under the cross-hair pattern. (Cross-hair has
a thickness of 2 pixels)
2.16
WHITE BALANCE AND COLOR CONVERSION
2.16.1 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.
2.17
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 2.16. 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
factory. Both LUT’s are available for modifications, and the user can generate and upload
his own custom LUT using the CHEETAH Configuration software – refer to Appendix B.
