I have an HSV image and am interested in a certain part of that image and I want to determine what the Hue Saturation and Value are of that area. I have gotten image selection to work and determine the area I am interested in but I don't think the way I calculate the channels are correct. The reason being that I the portion of the image I am looking at is white in RGB scale and I know that in HSV that white has a saturation of about (0..20) and a value(230..255) but the numbers printed out by the program don't come close in that range. I get a high 40 low 50 for S and -93 mostly. Is my calculation correct ?
public void splitChannels() {
Mat firstImage = Imgcodecs.imread("firstImage.jpg");
int width = 20;
int height = 20;
Rect roi = new Rect(120, 160, width, height);
Mat smallImg = new Mat(firstImage, roi);
int channels = smallImg.channels();
System.out.println("small pixels:" + smallImg.total());
System.out.println("channels:" + smallImg.channels());
int totalBytes = (int)(smallImg.total() * smallImg.channels());
byte buff[] = new byte[totalBytes];
smallImg.get(0, 0, buff);
for (int i=0; i< height; i++) {
// stride is the number of bytes in a row of smallImg
int stride = channels * width;
for (int j=0; j<stride; j+=channels) {
//I don't know if these channels calculations are correct.
int h = buff[(i * stride) + j];
int s = buff[(i * stride) + j + 1];
int v = buff[(i * stride) + j + 2];
// Do something with the hsv.
System.out.println("s: "+ s + " v: " + v);
}
}
}
