MATLAB: How to resize an image for face detection

Computer Vision Toolboxface detectionimage

Hi all,
I'm still new in Image processing. I just want to know:
1) What is the actual size for face detection function?
2) How to resize the image?
Because i got the warning that mentioned "Image is too big to fit on screen; displaying at 25% "
This is the normal code to process the image:
faceDetector = vision.CascadeObjectDetector;
I = imread('detectface.jpg');
bboxes = step(faceDetector, I);
IFaces = insertObjectAnnotation(I, 'rectangle', bboxes, 'Face');
figure, imshow(IFaces), title('Detected faces');

Best Answer

The vision.CascadeObjectDetector does not rely on you providing an image at a particular size.
That warning is only related to the image display. It is indicating that the image is too big for your monitor, and so MATLAB is displaying the image at a smaller size. This does not affect the face detection.
If you find that the faces you're looking for are not being detected correctly, I would suggest playing around with the MinSize, MaxSize and ScaleFactor parameters.
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