APPLIED OPERATIONS/Image Processing
OPERATION INSTRUCTIONS
2-229
Page
5 Prewitt filter
This filter enhances the contours of image grains in a similar way to the Sobel filter, but more
strongly than it. It has two filter formats, X and Y, as shown below. The format providing the
larger value after filtering is used.
X Y
-2 -2 -2 -2 0 2
000 -202
222 -202
The operation method is identical to Laplacian filtering except for the following point. See
section 2-6-1-1-1, “Laplacian filter”.
z Click the <Prewitt> button.
2-6-1-2 Noise Reduction
When random noise interferes with an image, its irregularity increases and it become harder
to see. Such noise can be reduced by means of filtering. Three kinds of filters are available
for noise reduction.
1 Averaging filter
The averaging filter is used to eliminate details in image or reduce noise. However, as it
makes everything in an image smooth, it also makes the edge sections dull, which
sometimes result in the image resolution deterioration. The filter format is as shown below.
111
111
111
The operation method is identical to Laplacian filtering except for the following point. See
section 2-6-1-1-1, “Laplacian filter”.
z Click the <Average> button.
<Prewitt> button
<Average> button
X1/9
To Next Page
Loading...
