Hi.
I am a student of CSE. I am doing some project using open CV. I need to load a image and save each of the regions predefined in the program, as a separate image. How do i do it in C++?
For example, suppose I have a form with 8 fields, I shall give the pixels from where to crop and the lengths along with it.
The program should crop the image according to the location.
The concept you are talking about is called Region Of Interest. In short- "ROI". The function for setting region of interest in opencv is
cvSetImageROI();
It takes 2 arguments, first one is the image ( our subject) second one is a rectangle defining the area to be set for ROI.
OpenCV is a very powerful tool. If you want to do small works you can use CImg.
Link
It is simple and lightweight.
@Synthesis,
Thanks. But when I type this:
cvSetImageROI(img, 645,1468,565,75);
it says too many arguments.
Thanks to you too. But I am afraid I have to do this in OpenCV.
Thomas,
By rectangle I literally meant a rectangle. Like this one: cvRect(645,1468,565,75)
So you should use : cvSetImageROI(img, cvRect(645,1468,565,75));
Thanks again synthesis. It was my misinterpretation. But now I have another problem:
cvSetImageROI(img, cvRect(390,290,280,60));
cvSaveImage("part1.bmp",img);
This works fine but when I add another one;
cvSetImageROI(img, cvRect(390,290,280,60));
cvSaveImage("part1.bmp",img);
cvSetImageROI(img, cvRect(1050,924,679,64));
cvSaveImage("part2.bmp",img);
This crashes just after I run it, giving some horrible printings in the screen. Stating cvImg out of bound. But my whole image is 3072×1024.
After the first call of setImageROI.
cvSetImageROI(img, cvRect(390,290,280,60));
Your image becomes 280×60. So next when you say
cvSetImageROI(img, cvRect(1050,924,679,64));
It can’t find the 1050 pixel within 280×60
You have to reset the ROI after each call
cvSetImageROI(img, cvRect(390,290,280,60));
cvSaveImage("part1.bmp",img);
cvResetImageROI(img);
cvSetImageROI(img, cvRect(1050,924,679,64));
cvSaveImage("part2.bmp",img);
cvResetImageROI(img);
You are most welcome Thank you from my heart!
That was a great support.
You are most welcome
