#ERROR 使用棋盘计算内在参数

Question

我正在做一个项目，我需要校准我的相机以便使用下面的代码获得相机矩阵（内部）。它 returns 出现以下错误：`

代码：

import numpy as np
import cv2
import glob
import argparse
import pathlib
ap = argparse.ArgumentParser()
ap.add_argument("-p", "--path", required=True, help="path to images folder")
ap.add_argument("-e", "--file_extension", required=False, default=".jpg", help="extension of images")
args = vars(ap.parse_args())
path = args["path"] + "*" + args["file_extension"]
# 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*9,3), np.float32)
objp[:,:2] = np.mgrid[0:9,0:6].T.reshape(-1,2)*0.0288
print(objp)
# 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.

#images = glob.glob('left/*.jpg') #read a series of images

images = glob.glob(path)

path = 'foundCorners'
#pathlib.Path(path).mkdir(parents=True, exist_ok=True) 

found = 0
for fname in images:  # Here, 10 can be changed to whatever number you like to choose
   img = cv2.imread(fname) # Capture frame-by-frame
   #print(images[im_i])
   gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
   # Find the chess board corners
   ret, corners = cv2.findChessboardCorners(gray, (9,6), None)
   # If found, add object points, image points (after refining them)
   if ret == True:
       objpoints.append(objp)   # Certainly, every loop objp is the same, in 3D.
       corners2 = cv2.cornerSubPix(gray,corners,(11,11),(-1,-1),criteria)
       imgpoints.append(corners2)
       # Draw and display the corners
       img = cv2.drawChessboardCorners(img, (9,6), corners2, ret)
       found += 1
       cv2.imshow('img', img)
       cv2.waitKey(500)
       # if you want to save images with detected corners 
       # uncomment following 2 lines and lines 5, 18 and 19
       image_name = path + '/calibresult' + str(found) + '.jpg'
       cv2.imwrite(image_name, img)

print("Number of images used for calibration: ", found)

# When everything done, release the capture
# cap.release()
cv2.destroyAllWindows()
#calibration
ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, gray.shape[::-1],None,None)



print ("Camera Matrix = |fx  0 cx|")
print ("                | 0 fy cy|")
print ("                | 0  0  1|")
print (mtx)
print('distortion coefficients=\n', dist)
#print('rotation vector for each image=', *rvecs, sep = "\n")
#print('translation vector for each image=', *tvecs, sep= "\n")

错误

Traceback (most recent call last):
File "calibration.py", line 67, in <module>
  ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, 
  gray.shape[::-1],None,None)
  NameError: name 'gray' is not defined

灰度参数是指正在处理的图像。
有谁知道为什么灰色图像不能被识别？

Answer 1

如果 images 为空则永远不会进入 for 循环并且永远不会创建 gray。很难确定这是否是原因 - 提供一个更简单的示例以及 path 目录的列表可能会有所帮助。

#ERROR 使用棋盘计算内在参数

#ERROR calculating the intrinsic parameter using chessboard

python

opencv

calibration

camera-calibration