图像处理———图像插值算法

最近邻插值算法的实现

#include
#include

using namespace std; using namespace cv;

Mat NearInter(Mat &srcImage, double kx, double ky) 
{ 	
int rows = cvRound(srcImage.rows*kx); 	
int cols = cvRound(srcImage.cols*ky); 	
Mat resultImg(rows, cols, srcImage.type()); 	
int i, j, x, y; 	
for (i = 0; i < rows; i++) 	
{ 		
x = static_cast<int>((i + 1) / kx + 0.5) - 1; 		
for (j = 0; j < cols; j++) 		
{ 			
y = static_cast<int>((j + 1) / ky+ 0.5) - 1; 			resultImg.at<Vec3b>(i, j) = srcImage.at<Vec3b>(x, y); 		
} 	
} 	
return resultImg; 
}

int main() 
{ 	
Mat srcImg = imread("D:\\Visual Studio 2015\\lena.bmp"); 	
Mat resultImg = NearInter(srcImg, 0.6, 1.2); 	
imshow("src", srcImg); 	
imshow("0.6,1.2", resultImg); 	
waitKey(0); 	
return 0; 
}

双线性插值代码的实现

uchar* dataDst = matDst1.data;
int stepDst = matDst1.step;
uchar* dataSrc = matSrc.data;
int stepSrc = matSrc.step;
int iWidthSrc = matSrc.cols;
int iHiehgtSrc = matSrc.rows;

for (int j = 0; j < matDst1.rows; ++j)
{
    float fy = (float)((j + 0.5) * scale_y - 0.5);
    int sy = cvFloor(fy);
    fy -= sy;
    sy = std::min(sy, iHiehgtSrc - 2);
    sy = std::max(0, sy);

    short cbufy[2];
    cbufy[0] = cv::saturate_cast((1.f - fy) * 2048);
    cbufy[1] = 2048 - cbufy[0];

    for (int i = 0; i < matDst1.cols; ++i)
    {
        float fx = (float)((i + 0.5) * scale_x - 0.5);
        int sx = cvFloor(fx);
        fx -= sx;

        if (sx < 0) {
            fx = 0, sx = 0;
        }
        if (sx >= iWidthSrc - 1) {
            fx = 0, sx = iWidthSrc - 2;
        }

        short cbufx[2];
        cbufx[0] = cv::saturate_cast((1.f - fx) * 2048);
        cbufx[1] = 2048 - cbufx[0];

        for (int k = 0; k < matSrc.channels(); ++k)
        {
            *(dataDst+ j*stepDst + 3*i + k) = (*(dataSrc + sy*stepSrc + 3*sx + k) * cbufx[0] * cbufy[0] + 
                *(dataSrc + (sy+1)*stepSrc + 3*sx + k) * cbufx[0] * cbufy[1] + 
                *(dataSrc + sy*stepSrc + 3*(sx+1) + k) * cbufx[1] * cbufy[0] + 
                *(dataSrc + (sy+1)*stepSrc + 3*(sx+1) + k) * cbufx[1] * cbufy[1]) >> 22;
        }
    }
}
cv::imwrite("linear_1.jpg", matDst1);

cv::resize(matSrc, matDst2, matDst1.size(), 0, 0, 1);
cv::imwrite("linear_2.jpg", matDst2);

双线性插值原理

学习手册Task01-06