FLIR
LEPTON® Engineering Datasheet
The information contained herein does not contain technology as defined by the EAR, 15 CFR 772, is publicly available,
and therefore, not subject to EAR. NSR (6/14/2018).
Information on this page is subject to change without notice.
Lepton Engineering Datasheet, Document Number: 500-0659-00-09 Rev: 203
36
Figure 13 - Comparison of Linear AGC and Classic/Lepton Variant of Histogram Equalization
A high value of clip limit high results in a mapping more like classic histogram equalization, whereas a low value
results in mapping more like linear AGC. For clip limit low, the opposite is true: a high value results in a mapping
more like linear AGC, whereas a low value results in a mapping more like classic histogram equalization. There
may be some overlap between the two parameters, but the difference between the two is that lowering the clip
limit high linearizes the brightness levels of the objects in the scene, while raising the clip limit low makes the
brightness of objects in the scene more representative of their temperature differences. The default values of
both parameters produce a good compromise between the two; however, because optimum AGC is highly
subjective and often application dependent, customers are encouraged to experiment to find settings most
appropriate for the target application.
By default, the histogram used to generate Lepton's 14-bit to 8-bit mapping function is collected from the full
array. In some applications, it is desirable to have the AGC algorithm ignore a portion of the scene when collecting
the histogram. For example, in some applications it may be beneficial to optimize the display to a region of
interest (ROI) in the central portion of the image. When the AGC ROI is set to a subset of the full image, any scene
content located outside of the ROI is not included in the histogram and therefore does not affect the mapping
function (note: this does not mean the portion outside of the ROI is not displayed or that AGC is not applied
there, only that those portions outside the AGC ROI do not influence the mapping function).
3.7
Video Output Format Modes
There are two video-output format modes:
