我想手动将 RGB 图像转换为 ycbcr 图像,反之亦然。但有一个错误,我找不到它。
我的图像看起来不正常。 这是我的代码:
void YCbCrToRGB(IplImage* ScrY, IplImage* ScrCb, IplImage* ScrCr, IplImage* DesR, IplImage* DesG, IplImage* DesB){
for(int i=0; i < ScrY->height; i++){
for(int j=0; j < ScrY->width; j++){
double Y = (double)(ScrY->imageData + ScrY->widthStep*i)[j];
double Cb = (double)(ScrCb->imageData + ScrCb->widthStep*i)[j];
double Cr = (double)(ScrCr->imageData + ScrCr->widthStep*i)[j];
Cb = Cb -128;
Cr = Cr -128;
int r;
int g;
int b;
(DesR->imageData + DesR->widthStep*i)[j] = (int)(1 * Y + 0 * Cb + 1.4 * Cr);
(DesG->imageData + DesG->widthStep*i)[j] = (int)(1 * Y - 0.343 * Cb - 0.711 *Cr);
(DesB->imageData + DesB->widthStep*i)[j] = (int)(1* Y + 1.765 * Cb + 0* Cr);
}}
void RGBtoYCbCr(IplImage* ScrR, IplImage* ScrG, IplImage* ScrB, IplImage* DesY, IplImage* DesCb, IplImage* DesCr){
for(int i=0; i < ScrR->height; i++){
for(int j=0; j < ScrR->width; j++){
double R = (double)(ScrR->imageData + ScrR->widthStep*i)[j];
double G = (double)(ScrG->imageData + ScrG->widthStep*i)[j];
double B = (double)(ScrB->imageData + ScrB->widthStep*i)[j];
(DesY->imageData + DesY->widthStep*i)[j] = 0.299 *R + 0.587 *G + 0.114 *B;
(DesCb->imageData + DesCb->widthStep*i)[j] = -0.1687 *R - 0.3313 *G + 0.5 *B + 128;
(DesCr->imageData + DesCr->widthStep*i)[j] = 0.5 *R - 0.4187 *G - 0.0813 *B + 128;
}
}}
int _tmain(int argc, _TCHAR* argv[])
{
try {
IplImage* img = cvLoadImage( "C:\\sad-cat.jpg",1 );
cvNamedWindow( "Example1", CV_WINDOW_AUTOSIZE );
cvShowImage( "Example1", img );
IplImage *r = cvCreateImage(cvGetSize(img), img->depth, 1);
IplImage *g = cvCreateImage(cvGetSize(img), img->depth, 1);
IplImage *b = cvCreateImage(cvGetSize(img), img->depth, 1);
cvSplit(img, b, g, r, NULL);
IplImage *y = cvCreateImage(cvGetSize(img), img->depth, 1);
IplImage *cb = cvCreateImage(cvGetSize(img), img->depth, 1);
IplImage *cr = cvCreateImage(cvGetSize(img), img->depth, 1);
RGBtoYCbCr(r,g,b,y,cb,cr);
IplImage *ycbcr = cvCreateImage(cvGetSize(img), img->depth, 3);
cvMerge(y,cb,cr,NULL,ycbcr);
cvNamedWindow( "YCbCr from RGB", CV_WINDOW_AUTOSIZE );
cvShowImage( "YCbCr from RGB", ycbcr );
YCbCrToRGB(y,cb,cr,r,g,b);
IplImage *RGBfromYCbCr = cvCreateImage(cvGetSize(img), img->depth, 3);
cvMerge(r,g,b,NULL,RGBfromYCbCr);
cvNamedWindow( "RGB from YCbCr", CV_WINDOW_AUTOSIZE );
cvShowImage( "RGB from YCbCr", RGBfromYCbCr );
cvWaitKey(0);
return 0;
}
catch( exception& e){
std::cout<<("An error occurred.") << std::endl;
std::cout << e.what() <<std::endl; // Print the error message.
cvWaitKey(0);
}
}
这是带有语法突出显示的链接:http://paste2.org/p/1569904
我认为这是一个类型转换错误或类似的事情。 非常感谢您
PS:请参阅公式和示例图片的评论(我不允许发布两个以上的链接或图像)
最佳答案
是的,这是一个选角问题。
double Y = (double)(ScrY->imageData + ScrY->widthStep*i)[j];
double Cb = (double)(ScrCb->imageData + ScrCb->widthStep*i)[j];
double Cr = (double)(ScrCr->imageData + ScrCr->widthStep*i)[j];
应该是
double Y = (uchar)(ScrY->imageData + ScrY->widthStep*i)[j];
double Cb = (uchar)(ScrCb->imageData + ScrCb->widthStep*i)[j];
double Cr = (uchar)(ScrCr->imageData + ScrCr->widthStep*i)[j];
对 RGBtoYCbCr
的前三行进行相同的更改。
此外,您还存在舍入错误。您应该在分配之前对结果进行四舍五入:
(DesY->imageData + DesY->widthStep*i)[j] = round( 0.299 *R + 0.587 *G + 0.114 *B);
(DesCb->imageData + DesCb->widthStep*i)[j] = round( -0.1687 *R - 0.3313 *G + 0.5 *B) + 128;
(DesCr->imageData + DesCr->widthStep*i)[j] = round( 0.5 *R - 0.4187 *G - 0.0813 *B) + 128;
最后,cvMerge(r,g,b,NULL,RGBfromYCbCr);
应该是cvMerge(b,g,r,NULL,RGBfromYCbCr);
因为cvShowImage
假定 BGR,而不是 RGB。
关于visual-c++ - OpenCV 手动将 RGB 转换为 YCbCr,反之亦然 (Visual C++),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/6973115/