23.3 Image Processing
Edge Filter Drop Down List
Use the “Edge Filter Drop Down List” to select an Edge Filter. The Edge Filter is an optional filter. The Edge Filters attempt to exaggerate the main feature(s) a user is looking for. The Edge Filters usually require a dark threshold filter. The Edge Filters extract and enhance edges & contours in an image by expressing intensity differences (gradients) between neighboring pixels as an intensity value. The basic variables are the differences between the top and bottom rows; the differences between the left and right columns; and the differences between the center point and its neighbors.
The batch codes for the Edge Filters are:
Code Meaning
0 No Edge Filter
1 Sobel 1 (Prewitt)
2 Sobel 2 (Sobel)
3 Sobel 3
4 Sobel 4
5 Gradient
6 Gradient, 45°
7 Sobel 1, 45°
8 Sobel 1, - 45°
9 Laplacian 4
10 CD 11
11 FD 11
12 FD 9
13 FD 7
14 Laplacian 5
15 Laplacian 8
16 Laplacian 9
17 Laplacian 16
18 Laplacian17
Threshold Filter Drop Down List
Use the “Threshold Filter Drop Down List” button to set the Threshold Filter. The Threshold Filters attempt to suppress the background. The Threshold Filter is NOT optional; if you do not set the Threshold Filter, the default filter will be used.
Choose an Edge Filter and a Threshold Filter where the sample objects will stand out, otherwise change the filter. If you do not have a filter, a customized filter has to be built. DO NOT make too many things stand out, i.e. as long as the area of interest stands out, the rest should show as little as possible.
Once you make a selection, the objects in the training images are black and the background is white. You should make the black area as small as possible, as long as it covers the key-segment(s), otherwise, switch to a different filter.
Clean-Up Filter Drop Down List
Use the “Clean-Up Filter Drop Down List” to select a Clean-Up Filter. The Clean-Up Filters will smooth the resulting image to reduce recognition error. The Clean-Up Filter is an optional filter.
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