两幅图像之间的Andr​​oid的Java个位图像素差 [英] Android java percentage bitmap pixel difference between two images

问题描述

我需要计算在Java中的两个图像在Android之间的像素差别。问题是，我有code返回不准确的结果。

I need to calculate pixel difference between two images in java on Android. The problem is that I have code that return inaccurate result.

例如。我有3个非常相似的图片，但它返回显著不同的结果为他们每个人的比较： PIC1 VS PIC2 = 1.71％; PIC1 VS PIC3 = 0.0045％; PIC2 VS PIC3 = 36.7％。

E.g. I have 3 very similar pictures but it returns significantly different results for comparison of each of them: pic1 vs pic2 = 1.71%; pic1 vs pic3 = 0.0045%; pic2 vs pic3 = 36.7%.

BitmapFactory.Options opt = new BitmapFactory.Options();
    opt.inPreferredConfig = Bitmap.Config.ARGB_8888;
    opt.inSampleSize = 5;
    Bitmap mBitmap1 = BitmapFactory.decodeFile("/sdcard/pic1.jpg", opt);
    Bitmap mBitmap2 = BitmapFactory.decodeFile("/sdcard/pic2.jpg", opt);

    int intColor1 = 0;
    int intColor2 = 0;
    for (int x = 0; x < mBitmap1.getWidth(); x++) {
       for (int y = 0; y < mBitmap1.getHeight(); y++) {
            intColor1 = mBitmap1.getPixel(x, y);
            intColor2 = mBitmap2.getPixel(x, y); 
            //System.out.print(" ("+ x + ","+ y +") c:" + intColor1);   
       }
       String resultString = String.valueOf(intColor1);

    }
    //now calculate percentage difference
    double razlika = (((double)intColor1 - intColor2)/intColor2)*100;

}

我想，我需要每个像素比较两个图像（intColor1（X，Y）与intColor2（X，Y）），但我怎么能做到这一点，并在以后计算百分比差异？

I think that I need to compare each pixel for both images (intColor1(x,y) vs intColor2(x,y)), but how I can do that, and to later calculate percentage difference?

推荐答案

是您正在使用的百分比公式是错误的。例如，＃333333是几乎相同的＃333332（和你的公式显示他们是0.003％不同）。另外＃323333几乎等同于＃333333，但您的公式表明，他们是3％不同。

The percentage formula that you're using is wrong. For example, #333333 is almost identical to #333332 (and your formula shows they're 0.003% different). Also #323333 is almost identical to #333333, but your formula shows they're 3% different.

您应该提取每个颜色的像素组成的每个位（Color.red（），Color.green（），Color.blue（）），计算出每个人的差别，进而获得了不同的组合比例。

You should extract each composing bit of each color pixel (Color.red() , Color.green(), Color.blue() ), calculate the difference of each of them, and then get the combined difference percentage.

虽然得到两个图像的差分的这种方法是简单和有效的，它有一个大的警告：如果这两个图像在内容上相同的，但由一个像素移位（到例如向右），你的方法将显示他们作为完全不同的。

While this method of getting the difference of the two images is simple and efficient, it has a big caveat: if the images are identical in content but shifted by one pixel (to the right for example), your method will show them as completely different.

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