Wide-angle or fisheye lens? The undistorted result and how to fix the perspective distortion

If you want to get a frontal view of what appears to be a rectangle, after undistortion you can apply an homography (it is easy to say, not so easy to do).

Can you be a little more specific? That is my goal. I have a homography set up but after I select the corners their reprojection has a high RMS.

Also, here are some better illuminated images. They are dark b/c they are bandpass IR 835 to )
I am using “vanilla” undistort routine. I’m not using the fisheye::undistort unless of course if they are the same thing. Is this both a fisheye & wide-angle lens? Should I be using the fisheye::undistort rather than the regular undistort?

drawKeypoints(rawImage, keypoints, im_with_keypoints, Scalar(0, 0, 255), DrawMatchesFlags::DRAW_RICH_KEYPOINTS);
					//
					undistort(im_with_keypoints, imageUndistorted, cam_intrinsic, distCoeffs);
					imshow("mode1 thread", imageUndistorted);
					imshow("rawImage, fisheye lens:", rawImage);

increased_ill