图像处理之光束效果

                                                             图像处理之光束效果

原理：

光束滤镜，对一幅图像完成光束效果，好似有一束光从图像本身激发出来，按照一定的角度

散发开来，光束滤镜是一种图像叠加效果，首先要借助于之前的完成的移动模糊滤镜，将一

幅图像按照一定的阈值二值化以后，加以移动模糊滤镜，将移动模糊之后的图像和原图像叠

加就产生了光束滤镜效果。

对光束滤镜而言，其最终效果除了移动模糊的三个参数以外，还取决于以下两个参数：

a.      图像RGB阈值的选取，建议可以直方图以后选取，程序以threshold表示

b.      光强度大小的值的选取，程序中以strength表示

程序运行效果如下：

关键代码解析：

计算RGB阈值代码如下– 输入的阈值范围为[0,1]

intthreshold3 = (int)(threshold*3*255);

求取二值像素的代码如下：

int l = r + g + b;

if (l < threshold3)

    [x] =0xff000000;

else {

l /= 3;

pixels[x] = a | (l << 16) | (l << 8) | l;

}

像素叠加乘以强度系数的代码如下（其中r,g,b分别代表RGB的三个颜色分量值）：

r = PixelUtils.clamp((int)(r * strength) + r2);

g = PixelUtils.clamp((int)(g * strength) + g2);

b = PixelUtils.clamp((int)(b * strength) + b2);

光束滤镜的完全源代码如下：

/*
** Copyright 2012 @gloomyfish. All rights reserved.
*/

package com.process.blur.study;

import java.awt.image.BufferedImage;

public class LaserFilter extends MotionFilter {

    private float threshold = 0.5f;
    private float strength = 0.8f;

    public LaserFilter() {
	}

	public void setThreshold( float threshold ) {
		this.threshold = threshold;
	}
	
	public float getThreshold() {
		return threshold;
	}
	
	public void setStrength( float strength ) {
		this.strength = strength;
	}
	
	public float getStrength() {
		return strength;
	}
	
    public BufferedImage filter( BufferedImage src, BufferedImage dst ) {
        int width = src.getWidth();
        int height = src.getHeight();
		int[] pixels = new int[width];
		int[] srcPixels = new int[width];

        BufferedImage laserImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);

		int threshold3 = (int)(threshold*3*255);
		for ( int y = 0; y < height; y++ ) {
			getRGB( src, 0, y, width, 1, pixels );
			for ( int x = 0; x < width; x++ ) {
				int rgb = pixels[x];
				int a = rgb & 0xff000000;
				int r = (rgb >> 16) & 0xff;
				int g = (rgb >> 8) & 0xff;
				int b = rgb & 0xff;
				int l = r + g + b;
				if (l < threshold3)
					pixels[x] = 0xff000000;
				else {
					l /= 3;
					pixels[x] = a | (l << 16) | (l << 8) | l;
				}
			}
			setRGB( laserImg, 0, y, width, 1, pixels );
		}

		laserImg = super.filter(laserImg, null );
		
		for ( int y = 0; y < height; y++ ) {
			getRGB( laserImg, 0, y, width, 1, pixels );
			getRGB( src, 0, y, width, 1, srcPixels );
			for ( int x = 0; x < width; x++ ) {
				int rgb = pixels[x];
				int a = rgb & 0xff000000;
				int r = (rgb >> 16) & 0xff;
				int g = (rgb >> 8) & 0xff;
				int b = rgb & 0xff;
				
				int rgb2 = srcPixels[x];
				// int a2 = rgb2 & 0xff000000;
				int r2 = (rgb2 >> 16) & 0xff;
				int g2 = (rgb2 >> 8) & 0xff;
				int b2 = rgb2 & 0xff;
				
				if ( r > 0 ) {
					r = clamp((int)(r * strength) + r2);
					g = clamp((int)(g * strength) + g2);
					b = clamp((int)(b * strength) + b2);
				} else {
					r = r2;
					g = g2;
					b = b2;
				}

				rgb = a | (r << 16) | (g << 8) | b;
				pixels[x] = rgb;
			}
			setRGB( laserImg, 0, y, width, 1, pixels );
		}

        return laserImg;
    }
    
	public String toString() {
		return "Light/Laser...";
	}
}