cv2.error: OpenCV(4.7.0) :-1: error: (-5:Bad argument) in function 'line'

Question

I am new to Python - Opencv and I have some difficulties when I try to run the code. It works well well when I have

imgpts, jac = cv.projectPoints(axisBoxes, rvecs, tvecs, mtx, dist)

        img = drawBoxes(img,corners2,imgpts)

Once I change it to

imgpts, jac = cv.projectPoints(axis, rvecs, tvecs, mtx, dist)

        img = draw(img,corners2,imgpts)

I get the following error: cv2.error: OpenCV(4.7.0) :-1: error: (-5:Bad argument) in function 'line'

Overload resolution failed:

• Can't parse 'pt1'. Sequence item with index 0 has a wrong type
• Can't parse 'pt1'. Sequence item with index 0 has a wrong type

the following is my complete code.

import numpy as np
import cv2 as cv
import glob


# Load previously saved data
with np.load('CameraParams.npz') as file:
    mtx, dist, rvecs, tvecs = [file[i] for i in ('CameraMatrix','DistortionParam','RotationVectors','TranslationVectors')]


def draw(img, corners, imgpts):

    corner = tuple(corners[0].ravel())
    img = cv.line(img, corner, tuple(imgpts[0].ravel()), (255,0,0), 10)
    img2 = cv.line(img, corner, tuple(imgpts[1].ravel()), (0,255,0), 10)
    img3 = cv.line(img, corner, tuple(imgpts[2].ravel()), (0,0,255), 10)

    return img


def drawBoxes(img, corners, imgpts):

    imgpts = np.int32(imgpts).reshape(-1,2)

    # draw ground floor in green
    img = cv.drawContours(img, [imgpts[:4]],-1,(0,255,0),-3)

    # draw pillars in blue color
    for i,j in zip(range(4),range(4,8)):
        img = cv.line(img, tuple(imgpts[i]), tuple(imgpts[j]),(255),3)

    # draw top layer in red color
    img = cv.drawContours(img, [imgpts[4:]],-1,(0,0,255),3)

    return img



criteria = (cv.TERM_CRITERIA_EPS + cv.TERM_CRITERIA_MAX_ITER, 30, 0.001)

objp = np.zeros((24*17,3), np.float32)
objp[:,:2] = np.mgrid[0:24,0:17].T.reshape(-1,2)
axis = np.float32([[3,0,0], [0,3,0], [0,0,-3]]).reshape(-1,3)
axisBoxes = np.float32([[0,0,0], [0,3,0], [3,3,0], [3,0,0],
                   [0,0,-3],[0,3,-3],[3,3,-3],[3,0,-3] ])


for image in glob.glob('images\*.png'):

    img = cv.imread(image)
    gray = cv.cvtColor(img,cv.COLOR_BGR2GRAY)
    ret, corners = cv.findChessboardCorners(gray, (24,17),None)

    if ret == True:

        corners2 = cv.cornerSubPix(gray,corners,(11,11),(-1,-1), criteria)

        # Find the rotation and translation vectors.
        ret, rvecs, tvecs = cv.solvePnP(objp, corners2, mtx, dist)

        # Project 3D points to image plane
        imgpts, jac = cv.projectPoints(axis, rvecs, tvecs, mtx, dist)

        img = draw(img,corners2,imgpts)
        cv.imshow('img',img)

        k = cv.waitKey(0) & 0xFF
        if k == ord('s'):
            cv.imwrite('pose'+image, img)



cv.destroyAllWindows()