【opencv实践】python-opencv张正友标定法

1. 画棋盘格

import cv2
import numpy as np
height_n = 8            #棋盘宽方向格子数目
width_n = 7           #棋盘高方向格子数目
block_width = 100
checker_img = np.zeros((height_n * block_width, width_n * block_width))         #全部填充白色
black_block = np.full((block_width,block_width),255)
for row in range(height_n):      #行
    for col in range(width_n):     #列
        if (row+col)%2==0:    #若行+列可被2整除，在下面操作中将色块填充黑色
            row_begin = row*block_width
            row_end = row_begin+block_width
            col_begin = col*block_width
            col_end = col_begin+block_width
            checker_img[row_begin:row_end,col_begin:col_end] = black_block       
cv2.imwrite("checker_board.jpg",checker_img)
cv2.imshow("checker_board",checker_img)
cv2.waitKey(0)

这里注意np.zeros(())这里要有两个括号，代表二维数组，生成效果图如下，想直接获取可以戳下面的链接～
链接: https://pan.baidu.com/s/1fSKSrf4pPVwDJaXtctYPfg
提取码: y8u5

2. 相机标定

调用摄像头并进行相机矫正，相机标定

import numpy as np
import cv2

# termination criteria
criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 30, 0.001)

# prepare object points, like (0,0,0), (1,0,0), (2,0,0) ....,(6,5,0)
objp = np.zeros((6*7,3), np.float32)
objp[:,:2] = np.mgrid[0:7,0:6].T.reshape(-1,2)

# Arrays to store object points and image points from all the images.
objpoints = [] # 3d point in real world space
imgpoints = [] # 2d points in image plane.

cap = cv2.VideoCapture(0)
if not cap.isOpened():
    print('camera not detected')
number = 0
while (cap.isOpened()):
    _, frame = cap.read()
    # img = cv2.imread(frame)
    cv2.imshow('result', frame)
    k = cv2.waitKey(1)

    if k & 0xff == ord('q') or number == 10 :
        break
    if k & 0xff == ord('s'):
        number += 1
        img = frame
        gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)

        # Find the chess board corners
        ret, corners = cv2.findChessboardCorners(gray, (7,6),None)

        # If found, add object points, image points (after refining them)
        if ret == True:
            objpoints.append(objp)

            corners2 = cv2.cornerSubPix(gray,corners,(11,11),(-1,-1),criteria)
            imgpoints.append(corners2)

            # Draw and display the corners
            img = cv2.drawChessboardCorners(img, (7,6), corners2,ret)
            cv2.imshow('img',img)
            cv2.waitKey(500)

ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, gray.shape[::-1],None,None)
print('ret',ret,'mtx',mtx,'dist',dist,'rvecs',rvecs,'tvecs',tvecs)


cv2.destroyAllWindows()

参考：
https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_calib3d/py_calibration/py_calibration.html#calibration