FLIR Camera Adjustments
102-PS242-100-01
Rev110
June 2014
Page 5 of 28
2.0
Automatic AGC Parameters
The first thing to understand is that the detector data is directly streamed from the sensor as 14-bit values
for each pixel in the array. The analog image is displayed using 8-bit values and almost all commercial
displays are 8-bit devices. In other words the video is displayed on a 0-255 scale rather than the full 0-
16384 resolution of the sensor. This means that there must be some compression to get the data into a
format that can be displayed. Throughout this note, there are histograms that are represented in Signal vs.
Number of Pixels. A histogram is a sorting of pixel values into intensity “bins”. What this means is the
bit value (which increases as pixels get brighter) is on the x-axis and the number of pixels in the image
that have that bit value is on the y-axis. This is a way of plotting image data in order to illustrate which
are the most significant intensity values. The algorithms attempt to compress the data in a meaningful
way that preserves as much of the image content as possible.
The Tau 2 core provides multiple AGC algorithms used to transform 14-bit data to 8-bit. These options
include the following, with associated parameters shown below each algorithm:
Plateau equalization
o
Plateau value
o
Maximum gain
o
ITT midpoint
o
ACE threshold
o
SSO value
o
Tail rejection
o
Region of Interest (ROI)
o
IIR filter
Information-based and Information-based equalization
o
Information-based Threshold
Linear histogram
o
ITT midpoint
o
ROI
o
IIR filter
Manual
o
Brightness
o
Contrast
o
IIR filter
