如何使用单应性计算物体在平面上的位置

Question

我必须做以下工作：

1. Draw a chessboard with at least 9x6 squares.
2. Take a video using a still camera and place the chessboard on the scene to find a Homography.
3. Remove the calibration target from the scene and compute the background model.
4. Place a moving object in the scene on the same plane as the Chessboard. Just a few seconds are enough
5. Calculate a homography using the frame with the chessboard
6. For each frame with the object: a. Subtract the background and calculate the object's position in the image. B. Use a homography and calculate the object's position on the plane where the chessboard was
7. Draw on a graph as found and connect the dots

第 6b 点是什么意思，怎么做？

我有的是这个：

我对吗？或者不是这样：？

更新
我试过这个代码：

chessboard_frame = cv.imread('pen.png',0)          # queryImage
chessboard_template = cv.imread('boardTemplate.png',0) 

pattern_size = (10,10)
_, corners1 = cv.findChessboardCorners(chessboard_frame, pattern_size)
_, corners2 = cv.findChessboardCorners(chessboard_template, pattern_size)
H, _ = cv.findHomography(corners1, corners2)

但它会引发以下错误：

错误：OpenCV(4.5.3) C:\Users\runneradmin\AppData\Local\Temp\pip-req-build-czu11tvl\opencv\modules\calib3d\src\fundam.cpp:378: 错误：(-5:Bad参数）输入数组应该是函数 'cv::findHomography' 中的 2D 或 3D 点集