是什么使得不失真代码对具有相同尺寸的多个棋盘图像不起作用？

Question

我是 OpenCV 的初学者-Python。我想知道什么可以使我的无失真代码适用于这张棋盘图片

不适合这个

知道棋盘的尺寸是一样的

我说的代码如下

import cv2
import numpy as np
criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 30, 0.001)
cbrow = 7
cbcol = 9

objp = np.zeros((cbrow * cbcol, 3), np.float32)
objp[:, :2] = np.mgrid[0:cbcol, 0:cbrow].T.reshape(-1,2)

objpoints = []  
imgpoints = []

CHECKERBOARD =  (7,9)

img = cv2.imread("ChessUOledVGA.jpg")

gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)

ret, corners = cv2.findChessboardCorners(gray, CHECKERBOARD, cv2.CALIB_CB_ADAPTIVE_THRESH+cv2.CALIB_CB_FAST_CHECK+cv2.CALIB_CB_NORMALIZE_IMAGE)
print(corners)

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, (cbcol, cbrow), corners2, ret)
        cv2.imshow('img', img)
        cv2.waitKey(0) 

 ret, mtx, dist , rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, gray.shape[::-1], None, None)
        print('mtx', mtx)
        print('dist',dist)
        img = cv2.imread('ChessUOledVGA.jpg', 1)
        h, w = img.shape[:2]  # get the size and the shape of the image h,w
        newcameramtx, roi = cv2.getOptimalNewCameraMatrix(mtx, dist, (w, h), 1, (w, h))
        print('newcameramtx', newcameramtx)
        dst = cv2.undistort(img, mtx, dist, None, newcameramtx)
        cv2.imwrite('result.jpg', dst)

谁能赐教。谢谢

Answer 1

您的棋盘尺寸必须为（每行角数，每列角数）->(9,7)。而且，你应该在传递到查找角函数之前对你的图像进行阈值处理，因为有问题的图像的四个角都有阴影。试试这个，它有效。

import cv2
import numpy as np
criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 30, 0.001)
cbrow = 7
cbcol = 9

objp = np.zeros((cbrow * cbcol, 3), np.float32)
objp[:, :2] = np.mgrid[0:cbcol, 0:cbrow].T.reshape(-1,2)

objpoints = []  
imgpoints = []

CHECKERBOARD =  (9,7)

img = cv2.imread("ChessUOledVGA.jpg")

gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
_, out = cv2.threshold(gray, 40, 255, cv2.THRESH_BINARY_INV)

ret, corners = cv2.findChessboardCorners(out, CHECKERBOARD, cv2.CALIB_CB_ADAPTIVE_THRESH+cv2.CALIB_CB_FAST_CHECK+cv2.CALIB_CB_NORMALIZE_IMAGE)
print(corners, ret)

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, (cbcol, cbrow), corners2, ret)
    cv2.imshow('img', img)
    cv2.waitKey(0) 

if 0:
    ret, mtx, dist , rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, gray.shape[::-1], None, None)
    print('mtx', mtx)
    print('dist',dist)
    img = cv2.imread('ChessUOledVGA.jpg', 1)
    h, w = img.shape[:2]  # get the size and the shape of the image h,w
    newcameramtx, roi = cv2.getOptimalNewCameraMatrix(mtx, dist, (w, h), 1, (w, h))
    print('newcameramtx', newcameramtx)
    dst = cv2.undistort(img, mtx, dist, None, newcameramtx)
    cv2.imwrite('result.jpg', dst)

是什么使得不失真代码对具有相同尺寸的多个棋盘图像不起作用？

What could make undistortion code not work for several chessboard images having the same dimensions?

python

opencv

computer-vision

distortion