How to read an image from memory instead of a file?

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I'd like to read an image from memory instead of a file. I'd like to know what is the counterparts of imread. I want to use

cv::Mat c(row, column, CV_8UC3, (*bitmap).data); cv::InputArray buf(c);

cv::Mat1b file = cv::imread("", CV_LOAD_IMAGE_GRAYSCALE);

bool ok = skel.thin(file, implementation_name, true);

where skel is called a VoronoiSkeleton downloaded from here

https://sites.google.com/site/rameyarnaud/research/c/voronoi

Thanks Jack