I want to get RGB values of an image (utf-8 160x120x3 matrix). I know which pixels I want, I nx1 vectors, xi and yi, which are indexes for each of these pixels of interest. I would like the output in nx3 format. I've had this problem in the past where I'd like to get data from a 3D matrix using 2D indecies. This works in 2D where you can grab several rows at once using the colon (xi,:), but not in 3D. I would like to extract the "hyper-row" so to speak.
What is the fastest way to do this? I have a working solution using impixel that is way too slow for this application. I could create a 3D logical matrix, but I am only sampling a few pixels relative to the total number, and sparse matrices don't work for this applicaiton. I usually tend to vectorize rather than use for loops, but it doesn't seem like there is a great alternative.
lab_image = randi(255,160,120,3);
test2d = randi(255,10,10);
