在ImageJ中实现一个Sobel过滤器
问题描述:
您好我试图通过创建我自己的插件在imagej中实现Sobel过滤器。我有代码可以工作,但它没有正确突出白色的边缘。我一直在尝试一段时间,我只是不知道我做错了什么,或者我不完全理解sobel滤波器的植入和/或不理解数学。任何帮助将不胜感激。这里是我的代码:在ImageJ中实现一个Sobel过滤器
import ij.*;
import ij.process.*;
import ij.gui.*;
import java.util.*;
import java.awt.*;
import ij.plugin.filter.*;
import ij.process.*;
import java.lang.Math.*;
public class Filter_Plugin implements PlugInFilter {
String title = null;
int sobel_x[][] = {{-1,0,1},
{-2,0,2},
{-1,0,1}};
int sobel_y[][] = {{-1,-2,-1},
{0,0,0},
{1,2,1}};
int pixel_x;
int pixel_y;
public int setup(String arg, ImagePlus im) {
title = im.getTitle();
return DOES_8G;
}
public void run(ImageProcessor ip) {
int w = ip.getWidth();
int h = ip.getHeight();
ImageProcessor copy = ip.duplicate();
for (int x=1; x < w-2; x++)
{
for (int y=1; y < h-2; y++)
{
pixel_x = 1/6 * (sobel_x[0][0] * copy.getPixel(x-1,y-1)) + (sobel_x[0][1] * copy.getPixel(x,y-1)) + (sobel_x[0][2] * copy.getPixel(x+1,y-1)) +
(sobel_x[1][0] * copy.getPixel(x-1,y)) + (sobel_x[1][1] * copy.getPixel(x,y)) + (sobel_x[1][2] * copy.getPixel(x+1,y)) +
(sobel_x[2][0] * copy.getPixel(x-1,y+1)) + (sobel_x[2][1] * copy.getPixel(x,y+1)) + (sobel_x[2][2] * copy.getPixel(x+1,y+1));
pixel_y = 1/6 * (sobel_y[0][0] * copy.getPixel(x-1,y-1)) + (sobel_y[0][1] * copy.getPixel(x,y-1)) + (sobel_y[0][2] * copy.getPixel(x+1,y-1)) +
(sobel_y[1][0] * copy.getPixel(x-1,y)) + (sobel_y[1][1] * copy.getPixel(x,y)) + (sobel_y[1][2] * copy.getPixel(x+1,y)) +
(sobel_y[2][0] * copy.getPixel(x-1,y+1)) + (sobel_y[2][1] * copy.getPixel(x,y+1)) + (sobel_x[2][2] * copy.getPixel(x+1,y+1));
int val = (int)Math.sqrt((pixel_x * pixel_x) + (pixel_y * pixel_y));
if(val < 0)
{
val = 0;
}
if(val > 255)
{
val = 255;
}
ip.putPixel(x,y,val);
}
}
}
}
答
有一个在你的计算错误:你是1/6仅第一加数(即您的矩阵的左上角)相乘。通过去除这个因素,我得到了下面的代码为我的作品:
import ij.*;
import ij.process.*;
import ij.gui.*;
import java.util.*;
import java.awt.*;
import ij.plugin.filter.*;
import ij.process.*;
import java.lang.Math.*;
public class Filter_Plugin implements PlugInFilter {
String title = null;
int sobel_x[][] = {{-1,0,1},
{-2,0,2},
{-1,0,1}};
int sobel_y[][] = {{-1,-2,-1},
{0,0,0},
{1,2,1}};
int pixel_x;
int pixel_y;
public int setup(String arg, ImagePlus im) {
title = im.getTitle();
return DOES_8G;
}
public void run(ImageProcessor ip) {
int w = ip.getWidth();
int h = ip.getHeight();
ImageProcessor copy = ip.duplicate();
for (int x=1; x < w-2; x++) {
for (int y=1; y < h-2; y++) {
pixel_x = (sobel_x[0][0] * copy.getPixel(x-1,y-1)) + (sobel_x[0][1] * copy.getPixel(x,y-1)) + (sobel_x[0][2] * copy.getPixel(x+1,y-1)) +
(sobel_x[1][0] * copy.getPixel(x-1,y)) + (sobel_x[1][1] * copy.getPixel(x,y)) + (sobel_x[1][2] * copy.getPixel(x+1,y)) +
(sobel_x[2][0] * copy.getPixel(x-1,y+1)) + (sobel_x[2][1] * copy.getPixel(x,y+1)) + (sobel_x[2][2] * copy.getPixel(x+1,y+1));
pixel_y = (sobel_y[0][0] * copy.getPixel(x-1,y-1)) + (sobel_y[0][1] * copy.getPixel(x,y-1)) + (sobel_y[0][2] * copy.getPixel(x+1,y-1)) +
(sobel_y[1][0] * copy.getPixel(x-1,y)) + (sobel_y[1][1] * copy.getPixel(x,y)) + (sobel_y[1][2] * copy.getPixel(x+1,y)) +
(sobel_y[2][0] * copy.getPixel(x-1,y+1)) + (sobel_y[2][1] * copy.getPixel(x,y+1)) + (sobel_x[2][2] * copy.getPixel(x+1,y+1));
int val = (int)Math.sqrt((pixel_x * pixel_x) + (pixel_y * pixel_y));
if(val < 0)
{
val = 0;
}
if(val > 255)
{
val = 255;
}
ip.putPixel(x,y,val);
}
}
}
}
你有没有看看Stephan Preibisch's Sobel Filter Plugin作为参考?
也许你应该让你的输出一个32位浮点图像,而不是在0和255
截断值啊谢谢你了!对此,我真的非常感激!我很害怕看看! –