(C/C++) Pixel Operation

1. Substraction(Difference)

이미지 차이/오류 확인

 

$  MSE(Mean Squared Error) = \frac{(Original - Output)^{2}}{Pixels} $

Diff_Y = (inputImg1[j * stride + 3 * i + 2] - inputImg2[j * stride + 3 * i + 2]) * 
         (inputImg1[j * stride + 3 * i + 2] - ipnutImg2[j * stride + 3 * i + 2])

 

2. Addition(Embedding)

워터마크와 유사

Y1 = 0.299 * inputImg1[j * stride + 3 * i + 2] + 
     0.587 * inputImg1[j * stride + 3 * i + 1] + 
     0.114 * inputImg1[j * stride + 3 * i + 0]
Y2 = 0.299 * inputImg2[j * stride + 3 * i + 2] + 
     0.587 * inputImg2[j * stride + 3 * i + 1] + 
     0.114 * inputImg2[j * stride + 3 * i + 0]
Y = Y1 / a + Y2 / b

 

3. Ratio

 

4. Multiplication

(1)

for (int j = 0; j < height; j++)
    {
        for (int i = 0; i < width; i++)
        {
            double Y1 = 0.299 * inputImg1[j * stride + 3 * i + 2] + 
                        0.587 * inputImg1[j * stride + 3 * i + 1] + 
                        0.114 * inputImg1[j * stride + 3 * i + 0];
            double Y2 = 0.299 * inputImg2[j * stride + 3 * i + 2] + 
                        0.587 * inputImg2[j * stride + 3 * i + 1] + 
                        0.114 * inputImg2[j * stride + 3 * i + 0];
            double Y = Y1 / a + Y2 / b;

            if (Y2 == 0) Y = 0;

            outputImg[j * stride + 3 * i + 0] = (unsigned char)(Y > 255 ? 255 : (Y < 0 ? 0 : Y));
            outputImg[j * stride + 3 * i + 1] = (unsigned char)(Y > 255 ? 255 : (Y < 0 ? 0 : Y));
            outputImg[j * stride + 3 * i + 2] = (unsigned char)(Y > 255 ? 255 : (Y < 0 ? 0 : Y));
        }
    }

 

(2) 

 

for (int j = 0; j < height; j++)
    {
        for (int i = 0; i < width; i++)
        {
            // inputImg2 색상반전
            inputImg2[j * stride + 3 * i + 0] = 255 - inputImg2[j * stride + 3 * i + 0];
            inputImg2[j * stride + 3 * i + 1] = 255 - inputImg2[j * stride + 3 * i + 1];
            inputImg2[j * stride + 3 * i + 2] = 255 - inputImg2[j * stride + 3 * i + 2];

            double Y1 = 0.299 * inputImg1[j * stride + 3 * i + 2] + 
                        0.587 * inputImg1[j * stride + 3 * i + 1] + 
                        0.114 * inputImg1[j * stride + 3 * i + 0];
            double Y2 = 0.299 * inputImg2[j * stride + 3 * i + 2] + 
                        0.587 * inputImg2[j * stride + 3 * i + 1] + 
                        0.114 * inputImg2[j * stride + 3 * i + 0];
            double Y = Y1 / a + Y2 / b;

            if (Y2 == 0) Y = 0;

            outputImg[j * stride + 3 * i + 0] = (unsigned char)(Y > 255 ? 255 : (Y < 0 ? 0 : Y));
            outputImg[j * stride + 3 * i + 1] = (unsigned char)(Y > 255 ? 255 : (Y < 0 ? 0 : Y));
            outputImg[j * stride + 3 * i + 2] = (unsigned char)(Y > 255 ? 255 : (Y < 0 ? 0 : Y));
        }
    }