Digital Signal Processing Reference
In-Depth Information
D.2.7 File
ContourTracer.java
D
Source Code
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import ij.process.ImageProcessor;
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public class ContourTracer {
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static final byte FOREGROUND = 1;
static final byte BACKGROUND = 0;
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ImageProcessor ip;
byte[][] pixelMap;
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int[][] labelMap;
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// label values in
labelMap
can be:
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//
0
... unlabeled
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// −
1
... previously visited background pixel
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// >
0
... valid region label
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public ContourTracer (ImageProcessor ip) {
this.ip = ip;
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int h = ip.getHeight();
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int w = ip.getWidth();
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pixelMap
= new byte[h+2][w+2];
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labelMap = new int[h+2][w+2];
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// create auxil. arrays
for (int v = 0; v < h+2; v++) {
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for (int u = 0; u < w+2; u++) {
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if (ip.getPixel(u-1,v-1) == 0)
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pixelMap[v][u] = BACKGROUND;
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else
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pixelMap[v][u] = FOREGROUND;
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}
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}
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}
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OuterContour traceOuterContour (int cx, int cy, int label) {
OuterContour cont = new OuterContour(label, 50);
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traceContour(cx, cy, label, 0, cont);
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return cont;
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}
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InnerContour traceInnerContour(int cx, int cy, int label) {
InnerContour cont = new InnerContour(label, 50);
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traceContour(cx, cy, label, 1, cont);
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return cont;
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}
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// trace one contour starting at
xS
,
yS
in direction
dir
Contour traceContour (int xS, int yS, int label, int dir,
Contour cont) {
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int xT, yT;
//
T
= successor of starting point
S
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int xP, yP;
//
P
=
”
previous“ contour point
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