Android实现图像灰度化、线性灰度变化和二值化处

1、图像灰度化：

public Bitmap bitmap2Gray(Bitmap bmSrc) { 
  // 得到图片的长和宽 
  int width = bmSrc.getWidth(); 
  int height = bmSrc.getHeight(); 
  // 创建目标灰度图像 
  Bitmap bmpGray = null; 
  bmpGray = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565); 
  // 创建画布 
  Canvas c = new Canvas(bmpGray); 
  Paint paint = new Paint(); 
  ColorMatrix cm = new ColorMatrix(); 
  cm.setSaturation(0); 
  ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm); 
  paint.setColorFilter(f); 
  c.drawBitmap(bmSrc, 0, 0, paint); 
  return bmpGray; 
}

2、对图像进行线性灰度变化

public Bitmap lineGrey(Bitmap image) {
  //得到图像的宽度和长度 
  int width = image.getWidth(); 
  int height = image.getHeight(); 
  //创建线性拉升灰度图像 
  Bitmap linegray = null; 
  linegray = image.copy(Config.ARGB_8888, true); 
  //依次循环对图像的像素进行处理 
  for (int i = 0; i < width; i++) { 
    for (int j = 0; j < height; j++) { 
      //得到每点的像素值 
      int col = image.getPixel(i, j); 
      int alpha = col & 0xFF000000; 
      int red = (col & 0x00FF0000) >> 16; 
      int green = (col & 0x0000FF00) >> 8; 
      int blue = (col & 0x000000FF); 
      // 增加了图像的亮度 
      red = (int) (1.1 * red + 30); 
      green = (int) (1.1 * green + 30); 
      blue = (int) (1.1 * blue + 30); 
      //对图像像素越界进行处理 
      if (red >= 255)  
      { 
        red = 255; 
      } 

      if (green >= 255) { 
        green = 255; 
      } 

      if (blue >= 255) { 
        blue = 255; 
      } 
      // 新的ARGB 
      int newColor = alpha | (red << 16) | (green << 8) | blue; 
      //设置新图像的RGB值 
      linegray.setPixel(i, j, newColor); 
    } 
  } 
  return linegray; 
} 

3、对图像进行二值化

public Bitmap gray2Binary(Bitmap graymap) { 
  //得到图形的宽度和长度 
  int width = graymap.getWidth(); 
  int height = graymap.getHeight(); 
  //创建二值化图像 
  Bitmap binarymap = null; 
  binarymap = graymap.copy(Config.ARGB_8888, true); 
  //依次循环，对图像的像素进行处理 
  for (int i = 0; i < width; i++) { 
    for (int j = 0; j < height; j++) { 
      //得到当前像素的值 
      int col = binarymap.getPixel(i, j); 
      //得到alpha通道的值 
      int alpha = col & 0xFF000000; 
      //得到图像的像素RGB的值 
      int red = (col & 0x00FF0000) >> 16; 
      int green = (col & 0x0000FF00) >> 8; 
      int blue = (col & 0x000000FF); 
      // 用公式X = 0.3×R+0.59×G+0.11×B计算出X代替原来的RGB 
      int gray = (int) ((float) red * 0.3 + (float) green * 0.59 + (float) blue * 0.11); 
      //对图像进行二值化处理 
      if (gray <= 95) { 
        gray = 0; 
      } else { 
        gray = 255; 
      } 
      // 新的ARGB 
      int newColor = alpha | (gray << 16) | (gray << 8) | gray; 
      //设置新图像的当前像素值 
      binarymap.setPixel(i, j, newColor); 
    } 
  } 
  return binarymap; 
}

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