Grayscale conversion algorithm of OpenCV's imread() -


what grayscale conversion algorithm opencv's

cv::imread("image.jpg", cv::imread_grayscale);

use?

in opencv 3.0:

  • cv::imread_color: image decompressed cv::jpegdecoder jcs_rgb (three channel image) , icvcvt_rgb2bgr_8u_c3r() function swap red , blue channels in order bgr format.
  • cv::imread_grayscale: image decompressed cv::jpegdecoder jcs_grayscale (one channel image), details of color conversion , other preprocessing/postprocessing handled libjpeg. finally, decompressed data copied internal buffer of given cv::mat.

ergo no cv::cvtcolor() called after reading image cv::imread_grayscale.


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