BOBCAT Hardware User’s Manual
Imperx, Inc.
Rev. 2.0.2
6421 Congress Ave.
11/20/2012
Boca Raton, FL 33487
+1 (561) 989-0006
146 of 265
3.2.1.3 Dual Threshold with Gray Scale
In some low contrast imaging applications, the simple threshold operation
along with a superimposed gray scale image might yield a good result. In
such cases a dual thresholding technique with a gray scale has to be
implemented – Formula 3.3. The image output is a gray scale image for all
gray level values between the selected threshold interval X1 and X2,
“black” for all gray levels lower than X1, and “white” for any gray levels
higher than X2. The user can set the optimum X1 (Low) and X2 (High)
threshold values, please note that X2 > X1. The image gray scale range is
only from values X1 to X2.
Output signal =>
“BLACK” if (input signal
X1)
“Gray Scale” if (X1 < input signal < X2)
“WHITE” if (input signal
X2)
(3.3)
3.2.1.4 Dual Threshold with Gray Scale Stretch
In some low contrast applications, the threshold operation along with a
gray scale stretch might yield a good result – Figure 3.3. This is similar to
dual threshold with a gray scale, but the image gray scale is digitally
stretched to full 12 bit gray scale – Formula 3.4. The user can set the
optimum X1 (Low) and X2 (High) threshold values, note that X2 > X1.
Output signal => “BLACK”
if (input signal
X1)
“Full Gray Scale” if (X1 < input signal < X2)
“WHITE”
if (input signal
X2)
(3.4)
Figure 3.3 – Original and processed image with threshold and gray scale stretch.
3.2.2 Multi Point Correction
Multi point correction is a modification of the slope of the camera transfer
function (TF), which results in the suppression or enhancement of certain image
