利用openCV找出已知图像中的角点， 利用slider bar 控制临界值， 并显示出通过临界值的角点像素， 并用non-maxima suprression 使之变稀疏并显示-routines in OpenCV to demonstrate the operations of the Harris Corner detector. 1. Open the image box_in_scene.jpg and show the image in a window.

2. Compute the minimum eigenvalue of that image.

3. Threshold the minimum eigenvalue, and draw the pixels that pass this threshold test in white, and the rest of the pixels in black. The actual threshold should be set by a slider which is on top of the window. I have found that a threshold of 0.01 for the minimum eigenvalue gives good results as the middle value of the slider.

4. Take the pixels that pass this threshold test and use a non-maxima suppression algorithm to thin out the potential corners. Draw the corners that pass the non-maxima suppression test in another window. These are the final corners.