如何在EmguCV中更改反转帧？

Question

Currently, I am working on a real-time IRIS detection application.

I want to perform an invert operation to the frames taken from the web camera, like this:

I managed to get this line of code, but this is not giving the above results. Maybe parameters need to be changed, but I am not sure.

CvInvoke.cvThreshold(grayframeright, grayframeright, 160, 255.0, Emgu.CV.CvEnum.THRESH.CV_THRESH_BINARY_INV);

Answer 1

From the images above it feels that the second image is the negative of the first image(correct me if I am wrong),

The function you are using is a threshold function,ie will render everything as white if it falls between the specified color range and other wise it will render it as black.

To find the negative of an image you can use one of the following methods.

Taking the NOT of an image.

 Image<Bgr, Byte> img2 = img1.Not();// imag1 can be a static image or your current captured frame

for more details you can refer the documentation here .

Answer 2

If you want to invert an image you can do the following:

Mat white = Mat::ones(grayframeright.rows, grayframeright.cols, grayframeright.type);
Mat dst = white - grayframeright;

Also note that pupil can be detected with OpenCV detector initialized with HAAR cascade for eyes that OpenCV code comes with.