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OLD: Trying the OpenCV tutorial for camera calibration.
Kindly look for part two right after "EDIT" below the the first python code section

I receive this error:

OpenCV Error: Assertion failed (nimages > 0 && nimages == (int)imagePoints1.total() && (!imgPtMat2 || nimages == (int)imagePoints2.total())) in collectCalibrationData, file /build/opencv-L2vuMj/opencv-3.2.0+dfsg/modules/calib3d/src/calibration.cpp, line 3106
Traceback (most recent call last):
  File "cse598a2.py", line 46, in <module>
    None)
cv2.error: /build/opencv-L2vuMj/opencv-3.2.0+dfsg/modules/calib3d/src/calibration.cpp:3106: error: (-215) nimages > 0 && nimages == (int)imagePoints1.total() && (!imgPtMat2 || nimages == (int)imagePoints2.total()) in function collectCalibrationData

I have seen similar errors but failed to find the one with the error code 3106. 3193 3415

I also tried to look for the file calibration.cpp but couldn't find it in Ubuntu 18.04 to try and see where the problem is. Dimensions do check out as stated on other posts.

here is my code

import cv2
import os
import numpy as np
import sys


path = os.path.expanduser('~') + '/catkin_ws/src/cse598a2/images/task_1'
entries = os.listdir(path)


object_points = np.zeros((6*9,3), np.float32)
object_points[:,:2] = np.mgrid[0:9,0:6].T.reshape(-1,2)

objectt_points = [] # A 3d point in real world space
image_points = [] # for 2d points in image plane.

c = 0

for each in entries:
    if c == 5: break;
    if (each[0] == 'r'):
        image = (cv2.imread(path + '/' + each))
    
        image_gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
        value_return, corners = cv2.findChessboardCorners(image_gray,
                                                      (6,9),
                                                      flags=cv2.CALIB_CB_FAST_CHECK)
        if value_return:
            objectt_points.append(object_points)
            image_points.append(corners)
        
    print len(objectt_points)
    print len(image_points)
    c = c + 1


#print (objectt_points)
#print (image_points)

# sys.exit(0)

value_return, matrix, dist, rvecs, tvecs = cv2.calibrateCamera(object_points,
                                                                   image_points,
                                                                   image_gray.shape[::-1],
                                                                   None,
                                                                   None)

height,  width = image_gray.shape[:2]
newcameramtx, region_interest = cv2.getOptimalNewCameraMatrix(mtx, dist, (width,height), 1, (width,height))

image_undistorted = cv2.undistort(image_gray, matrix, distance, None, newcameramtx)
x, y, width, height = region_interest
image_undistorted = image_undistorted[y:y+height, x:x+height]

print dist.shape

EDIT: PART-TWO
This time, I am unable to resolve the problem. The last time, the problem was that I was providing a wrong argument, this time, I have checked it first and don't understand where is the problem. I have checked code examples to see the methodology. Stereo Calibration Example on Stack Overflow Here is the error

OpenCV Error: Assertion failed (nimages > 0 && nimages == (int)imagePoints1.total() && (!imgPtMat2 || nimages == (int)imagePoints2.total())) in collectCalibrationData, file /build/opencv-L2vuMj/opencv-3.2.0+dfsg/modules/calib3d/src/calibration.cpp, line 3106
Traceback (most recent call last):
  File "cse598a2_t2.py", line 81, in <module>
    flags=cv2.CALIB_FIX_INTRINSIC))
cv2.error: /build/opencv-L2vuMj/opencv-3.2.0+dfsg/modules/calib3d/src/calibration.cpp:3106: error: (-215) nimages > 0 && nimages == (int)imagePoints1.total() && (!imgPtMat2 || nimages == (int)imagePoints2.total()) in function collectCalibrationData


import cv2
import os
import numpy as np
import sys


path = os.path.expanduser('~') + '/catkin_ws/src/cse598a2/images/task_2'
entries = os.listdir(path)


object_file_storage_L = cv2.FileStorage('camera_L.yml', flags=cv2.FILE_STORAGE_READ)
object_file_storage_R = cv2.FileStorage('camera_R.yml', flags=cv2.FILE_STORAGE_READ)

dis_L = object_file_storage_L.getNode('cam_L_dispar').mat()
dis_R = object_file_storage_R.getNode('cam_R_dispar').mat()

mat_L = object_file_storage_L.getNode('cam_L_matrix').mat()
mat_R = object_file_storage_R.getNode('cam_R_matrix').mat()

object_file_storage_L.release()
object_file_storage_R.release()


object_points = np.zeros((6*9,3), np.float32)
object_points[:,:2] = np.mgrid[0:9,0:6].T.reshape(-1,2)

objectt_points = [] # A 3d point in real world space
image_points_L = [] # for 2d points in image plane.
image_points_R = [] # for 2d points in image plane.

file_l0 = 'left_0.png'
file_l1 = 'left_1.png'
file_r0 = 'right_0.png'
file_r1 = 'right_1.png'

image = cv2.imread(path + '/' + file_l0)
image_gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
value_return, corners = cv2.findChessboardCorners(image_gray, (6, 9), flags=cv2.CALIB_CB_FAST_CHECK)
print corners.shape

if value_return:
    objectt_points.append(object_points)
    image_points_L.append(corners)

image = cv2.imread(path + '/' + file_l1)
image_gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
value_return, corners = cv2.findChessboardCorners(image_gray, (6, 9), flags=cv2.CALIB_CB_FAST_CHECK)
print corners.shape

if value_return:
    objectt_points.append(object_points)
    image_points_L.append(corners)

image = cv2.imread(path + '/' + file_r0)
image_gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
value_return, corners = cv2.findChessboardCorners(image_gray, (6, 9), flags=cv2.CALIB_CB_FAST_CHECK)
print corners.shape

if value_return:
    objectt_points.append(object_points)
    image_points_L.append(corners)

image = cv2.imread(path + '/' + file_r1)
image_gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
value_return, corners = cv2.findChessboardCorners(image_gray, (6, 9), flags=cv2.CALIB_CB_FAST_CHECK)
print corners.shape

if value_return:
    objectt_points.append(object_points)
    image_points_L.append(corners)

retval, cameraMatrix1, distCoeffs1, cameraMatrix2, distCoeffs2, R, T, E, F = (
cv2.stereoCalibrate(objectt_points,
                    image_points_L,
                    image_points_R,
                    mat_L,
                    dis_L,
                    mat_R,
                    dis_R,
                    image_gray.shape,
                    flags=cv2.CALIB_FIX_INTRINSIC))
Vishwad
  • 139
  • 8

1 Answers1

0

This is the solution for the first part related to
cameraCalibration()
Never mind, I think I found it. There is an issue with the arguments I provided for the function calibrateCamera()

Now there is a new problem on 21/feb/2021 under EDIT.

Solution for EDIT, problem part 2

The code has errors and there was a slight conceptual problem. image_points_R was never filled and all was appended to image_points_L. The conceptual problem was that 4 times 3D coordinates need not be appended since both L and R cams for a single time frame correspond to the same coordinates.

commented lines 60 and 69, corrected lines 61 and 70

Vishwad
  • 139
  • 8