I need to know, is loaded img grayscale or color to not process grayscale. My idea is get grayscale by cvtColor(src,src_gray,COLOR_BGR2GRAY) and compare with loaded img.
Perhaps there is a standard or a more interesting variant?
Hi!
If you are loading a Gray scale image as a Color image. You can check that by Comparing RGB Values of All the pixels. For Example If the image is a Gray Scale image then
if(R=G=B)
//Grayscale
For more accurate results you can introduce some thresholds values. i.e
if((abs(R-G)< Threshold))// Threshold-> can be greater than zero. eg 0.006
//Grayscale
By this way you can get pretty good results.
Load image with default depth using the macro CV_LOAD_IMAGE_ANYDEPTH like,
const cv::Mat src = cv::imread(filename, CV_LOAD_IMAGE_ANYDEPTH);
And check the number of channel using Mat::channels like,
std::cout<<src.channels();
If you are not interested by a color image (ie you only want to convert color image into grayscale) and to avoid testing all values (RGB, RGBA, etc), you could directly load your image in grayscale:
cv::Mat image = cv::imread( "myImage.jpg/png/...", CV_LOAD_IMAGE_GRAYSCALE );
The mat 'image' will be in grayscale. See the doc of imread for more information.
Asked: 2014-07-04 07:32:49 -0600
Seen: 32,086 times
Last updated: Jul 05 '14