Rockwell Automation 5370-CVIM2 Module - Manual (Page 315)

5 Chapter Chapter 7
Inspection Tools
7–77
The availability of the contrast function, and the maximum contrast values,
are both related to the specific kernel selection. Table 7.3 identifies the kernel
selections and their corresponding contrast functions and values.
Table 7.3 Summary Table of Kernels and Maximum Contrast Values
Kernel Selections Contrast Function Enabled? Max. Contrast Value
Sobel X Yes 2
Sobel Y Yes 2
Laplace Yes 1
X Edge Yes 3
Y Edge Yes 3
Average 3x3 Yes 3
Average 5x5 Yes 4
User 3x3 ➀ ➀
User 5x5 ➀ ➀
➀
Depends on the kernel configuration.
Convolution Kernels and LUT Selections
Table 7.4 correlates the convolution kernels (except the two user–
configurable kernels) with the LUTs (look–up tables). The table shows
whether a kernel produces a signed image, which contains pixel values
between –128 and +127, or an unsigned image, which contains pixel values
between 0 and +255, and it indicates which LUTs are most appropriate for
each kernel.
Table 7.4 Summary Table: Kernels and Appropriate LUTs
Convolution Output Image:
Appropriate LUTs
Convolution
Kernel
Output Image:
Signed or Unsigned Ident. Sign Abs. Inv. Clip S.Clip Thres. S.Thr.
Sobel X Signed No Yes Yes No No ➀ No Yes
Sobel Y Signed No Yes Yes No No ➀ No Yes
Laplace Signed No Yes Yes No No ➀ No Yes
X Edge Signed No Yes Yes No No ➀ No Yes
Y Edge Signed No Yes Yes No No ➀ No Yes
Average 3x3 Unsigned Yes No No Yes Yes No Yes No
Average 5x5 Unsigned Yes No No Yes Yes No Yes No
➀
May be useful if threshold is adjusted to remove negative values.