C++ openCV mat initialization

2
votes

I am completely new to OpenCV and I'm trying to initialize two cv::Mat matrices from two different type of data. One is simple one-channel array of uint16_t gray values, second should hold RGB values from array of uint8_t values holding RGB 565 (each pixel occupy 2 uint8_t, so it's basically array of uint16_t). I'd like to have one single-chanell matrix, and one 3-chanell matrix (which will probably be converted to one chanelly sometime... but I'm not quite there yet.

function(uint16_t *oneChanell, int oneChanellWidth, int oneChanellHeight, uint8_t *rgb, int rgbWidth, int rgbHeight){
...
    cv::Mat M1 = cv::Mat(oneChanellHeight, oneChanellWidth, CV_16UC1, oneChanell);
    cv::Mat M2 = cv::Mat(rgbHeight, rgbWidth, CV_16UC3, rgb);
...
}

Now, I am aware that the second initialization is wrong. So that is one part of my question, how to best convert array of rgb565values to cv::Mat. In my understanding however, the first initialization should work. When tested with cv::imwrite(), the first yields just blank white picture of correct size, the second three partially overlapping silhouettes of the same (correct) picture, but not in RGB. Any advice would be appreciated.

1
c++opencvopencv-mat

1 Answers

3
votes

use cv::cvtColor to convert the mat M2 from RGB565 to RGB format.

...

cv::Mat M2 = cv::Mat(rgbHeight, rgbWidth, CV_16UC1, rgb);
// M2.depth()    = 2 # CV_16U
// M2.channels() = 1 # single channel with each element having 16 bit



//convert mat format from bgr565 to rgb
cv::Mat M2_rgb;
cv::cvtColor(M2, M2_rgb, COLOR_BGR5652RGB);

...