图像处理之半调色融合

图像处理之半调色融合

图像处理中错误扩散，抖动算法在在数字半调技术中有着重要的应用，是报纸，黑白

打印机等输出设备常常采用的技术。常见的图像半调技术有矩阵错误扩散，弗洛伊德-

斯坦德伯格错误扩散，空间填充曲线采样错误扩散等。本文借助半调算法，实现两张

图像的融合，将背景纹理融合到目标图像中，创造惊艳的图像处理效果。

算法基本思想：

读取纹理图像像素点P(x,y)与目标图像对应像素D(x,y)，输入参数调节S取值范围[0~1]

根据参数S计算颜色差值cs = S * 255，，假设像素值分别为P(x, y) =mv, D(x, y) = dv

则融合后的像素值pd(x, y)=255*(1-3x^2 – 2x^3)其中x = (mv – (dv – cs)/2cs)

运行效果：

背景图像分别为：

程序源代码：

package com.gloomyfish.filter.study;import java.awt.image.BufferedImage;/** * A filter which uses a another image as a ask to produce a halftoning effect. */public class HalftoneFilter extends AbstractBufferedImageOp {private float softness = 0.1f;private boolean invert;private BufferedImage mask;public HalftoneFilter() {System.out.println("Stylize/Halftone…");}/** * Set the softness of the effect in the range 0..1. * @param softness the softness* @min-value 0* @max-value 1 */public void setSoftness( float softness ) {this.softness = softness;}/** * Get the softness of the effect. * @return the softness* @see #setSoftness */public float getSoftness() {return softness;}/** * Set the halftone background image. * @param BufferedImage maskImage* @see #getMask */public void setMask( BufferedImage maskImage ) {this.mask = maskImage;}public void setInvert( boolean invert ) {this.invert = invert;}public BufferedImage filter( BufferedImage src, BufferedImage dst ) {int width = src.getWidth();int height = src.getHeight();if ( dst == null )dst = createCompatibleDestImage( src, null );if ( mask == null )return dst;int maskWidth = mask.getWidth();int maskHeight = mask.getHeight();// scale to [0~255]float s = 255*softness;int[] inPixels = new int[width];int[] maskPixels = new int[maskWidth];for ( int y = 0; y < height; y++ ) {getRGB( src, 0, y, width, 1, inPixels ); // get row pixelsgetRGB( mask, 0, y % maskHeight, maskWidth, 1, maskPixels ); // get row pixelsfor ( int x = 0; x < width; x++ ) {int maskRGB = maskPixels[x % maskWidth];int inRGB = inPixels[x];if ( invert )maskRGB ^= 0xffffff;// start to halftone here!!int ir = (inRGB >> 16) & 0xff;int ig = (inRGB >> 8) & 0xff;int ib = inRGB & 0xff;int mr = (maskRGB >> 16) & 0xff;int mg = (maskRGB >> 8) & 0xff;int mb = maskRGB & 0xff;int r = (int)(255 * (1-cubeInterpolation( ir-s, ir+s, mr )));int g = (int)(255 * (1-cubeInterpolation( ig-s, ig+s, mg )));int b = (int)(255 * (1-cubeInterpolation( ib-s, ib+s, mb )));inPixels[x] = (inRGB & 0xff000000) | (r << 16) | (g << 8) | b;}setRGB( dst, 0, y, width, 1, inPixels );}return dst;}public static float cubeInterpolation(float a, float b, float x) {if (x < a)return 0;if (x >= b)return 1;x = (x – a) / (b – a);return x*x * (3 – 2*x);}}

那些无法讲述的悲伤和苍凉，