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Java > Open Source Codes > JSci > instruments > PTTemplateCross


1 package JSci.instruments;
2
3 import java.awt.*;
4 import java.io.*;
5
6 /**
7  * Locating a template in the image
8  */
9 class PTTemplateCross {
10
11     /** How fast the search area is moved (0-1) */
12     public static double REGION_SPEED = 0.2;
13
14     private int number;
15     private Rectangle position;
16     private Rectangle searchArea;
17     private Image templateImage;
18     private double templateBckgrnd;
19     private double[][] corr;
20     private static int nextN = 0;
21     
22     private double x;
23     private double y;
24     private double ox; // original position with respect to the upper left corner of the searchArea
25 private double oy;
26     private double cx; // floating point position of the upper left corner of the searchArea
27 private double cy;
28
29     private int fromImg(byte c) { if (c>=0) return (int)c; else return (int)(256+c); }
30
31     /**
32      * @param p initial position of the template in the image
33      * @param s search area
34      * @param i the image to be searched (template)
35      */
36     public PTTemplateCross(Rectangle p, Rectangle s, Image i) {
37     // template number
38 number = nextN++;
39     // rectangles
40 position = (Rectangle)p.clone();
41     searchArea = (Rectangle)s.clone();
42     ox=position.x-searchArea.x;
43     oy=position.y-searchArea.y;
44     cx=searchArea.x;
45     cy=searchArea.y;
46     // template image
47 templateImage = i;
48     // template background
49 int m,n;
50     templateBckgrnd = 0.0;
51     for (m=0;m<templateImage.getWidth();m++)
52         for (n=0;n<templateImage.getHeight();n++)
53         templateBckgrnd+=fromImg(templateImage.getData()[templateImage.getOffset()+m+n*templateImage.getScansize()]);
54     templateBckgrnd/=templateImage.getWidth()*templateImage.getHeight();
55     // correlation function
56 corr = new double[searchArea.width-templateImage.getWidth()]
57         [searchArea.height-templateImage.getHeight()];
58     }
59
60     /**
61      * Locates the template; draws the current bounds of the template on the image
62      * @param img the image that has been just grabbed
63      */
64     public void find(Image img) {
65
66     double max=-100.0;
67     int maxx = 0;
68     int maxy = 0;
69
70     for (int j=0;j<corr.length;j++) for (int k=0;k<corr[0].length;k++) {
71         corr[j][k]=0.0;
72         for (int m=0;m<templateImage.getWidth();m++) for (int n=0;n<templateImage.getHeight();n++)
73         corr[j][k]+=
74             fromImg(img.getData()[img.getOffset()+(j+m+searchArea.x)+(k+n+searchArea.y)*img.getScansize()])*
75             (fromImg(templateImage.getData()[templateImage.getOffset()+m+n*templateImage.getScansize()])-templateBckgrnd);
76         if (corr[j][k]>max) {
77         maxx=j;
78         maxy=k;
79         max=corr[j][k];
80         }
81     }
82     
83     double Dx,Dy;
84     if (maxx==0 | maxy==0 | maxx==corr.length-1 | maxy==corr[0].length-1) {Dx=Dy=0;}
85     else {
86         double cxp=(corr[maxx+1][maxy]-corr[maxx-1][maxy])/2.0;
87         double cyp=(corr[maxx][maxy+1]-corr[maxx][maxy-1])/2.0;
88         double cxpyp=(corr[maxx+1][maxy+1]-corr[maxx+1][maxy-1]-corr[maxx-1][maxy+1]+corr[maxx-1][maxy-1])/4.0;
89         double cxpp=-2.0*corr[maxx][maxy]+corr[maxx+1][maxy]+corr[maxx-1][maxy];
90         double cypp=-2.0*corr[maxx][maxy]+corr[maxx][maxy+1]+corr[maxx][maxy-1];
91         double Det=cxpp*cypp-cxpyp*cxpyp;
92         Dx=-(cxp*cypp-cyp*cxpyp)/Det;
93         Dy=-(cxpp*cyp-cxpyp*cxp)/Det;
94     }
95     
96     x=searchArea.getMinX()+maxx+Dx;
97     y=searchArea.getMinY()+maxy+Dy;
98
99     cx+=(x-searchArea.x-ox)*REGION_SPEED;
100     cy+=(y-searchArea.y-oy)*REGION_SPEED;
101     if (cx<0) cx=0;
102     if (cx+searchArea.width>=img.getWidth()) cx=img.getWidth()-1-searchArea.width;
103     if (cy<0) cy=0;
104     if (cy+searchArea.height>=img.getHeight()) cy=img.getHeight()-1-searchArea.height;
105
106     position.setLocation((int)Math.rint(x),(int)Math.rint(y));
107     searchArea.setLocation((int)Math.rint(cx),(int)Math.rint(cy));
108
109     img.addOverlay(new Overlay() {
110         public void paint(Graphics g) {
111             Graphics2D g2 = (Graphics2D)g;
112             g2.setColor(Color.RED);
113             g2.draw(position);
114             g2.setColor(Color.MAGENTA);
115             g2.draw(searchArea);
116             g2.drawString(PTTemplateCross.this.toString(),searchArea.x,searchArea.y+searchArea.height+12);
117         }
118         });
119
120     }
121
122     /**
123      * @return the (sequential) number of the template
124      */
125     public int getN() {return number;}
126
127     /** @return the number of the cross; increases for each instance is created */
128     public String JavaDoc toString() { return ""+number; }
129
130     /**
131      * @return X position of the object
132      */
133     public double getX() {return x;}
134
135     /**
136      * @return Y position of the object
137      */
138     public double getY() {return y;}
139
140 }
141
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