pass the correct rgb->gray coefficients to PNG decoder, to match cvtColor's.
pass the correct rgb->gray coefficients to PNG decoder, to match cvtColor's.

opencv/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,apavlenko/opencv,apavlenko/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv