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Finding corresponding pixel coordinate of a single point before and after cv2.remap

Let's begin by saying that i have a static image, called it leftFrame.

This frame is passed to method cv2.remap(leftFrame, map1, map2, cv2.INTER_LANCZ0S4,0), so that every pixel from original image (leftFrame) is reallocated to a new position. Given that map1 and map2 are output from cv2.initUndistortRectifyMap(MLS, dLS, RL, PL,imgShape,cv2.CV_16SC2), with MLS, dLS, RL, PL had been calculated before.

Things are done well,

HOWEVER, now I just want to get the corresponding pixel coordinate of a single point in the new frame, given the original pixel coordinate of that point in the initial, original frame (leftFrame).

How can I achieve it?

The code is simplified to be like this:

Left_Stereo_Map = cv2.initUndistortRectifyMap(MLS, dLS, RL, PL,imgShape,cv2.CV_16SC2)
    leftCap = cv2.VideoCapture(PORT)
    while (True):
       # Collect image continously
       ret1, leftFrame = leftCap.read()
       Left_nice = cv2.remap(leftFrame, Left_Stereo_Map[0], Left_Stereo_Map[1], cv2.INTER_LANCZOS4, cv2.BORDER_CONSTANT, 0)
       original_x = PREDEFINED_X
       original_y = PREDEFINED_Y
       x_after = ?
       y_after = ?

       cv2.waitkey(1)

Thanks everyone for spending your time reading this question. Wish you safe in this time!