/**
     * 将彩色图转换为黑白图
     *
     * @param 位图
     * @return 返回转换好的位图
     */
    public static Bitmap convertToBlackWhite(Bitmap bmp) {
        int width = bmp.getWidth(); // 获取位图的宽
        int height = bmp.getHeight(); // 获取位图的高

        int[] pixels = new int[width * height]; // 通过位图的大小创建像素点数组

        bmp.getPixels(pixels, 0, width, 0, 0, width, height);
        int alpha = 0xFF > 16);
                int green = ((grey & 0x0000FF00) >> 8);
                int blue = (grey & 0x000000FF);

                grey = (int) (red * 0.3 + green * 0.59 + blue * 0.11);
                grey = alpha | (grey