import cv2
import numpy as np
import os
import glob

# Defining the dimensions of checkerboard
CHECKERBOARD = (16,22)
criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 30, 0.001)

# Creating vector to store vectors of 3D points for each checkerboard image
objpoints = []
# Creating vector to store vectors of 2D points for each checkerboard image
imgpoints = [] 


# Defining the world coordinates for 3D points
objp = np.zeros((1, CHECKERBOARD[0] * CHECKERBOARD[1], 3), np.float32)
objp[0,:,:2] = np.mgrid[0:CHECKERBOARD[0], 0:CHECKERBOARD[1]].T.reshape(-1, 2)
prev_img_shape = None


h = 480
w = 640

# Extracting path of individual image stored in a given directory
images = glob.glob('/home/ros/Bureau/ca_ur5/*.jpg')
for fname in images:
	img = cv2.imread(fname)
	h,w = img.shape[:2]
	gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
	print(gray)
	# Find the chess board corners
	# If desired number of corners are found in the image then ret = true
	ret, corners = cv2.findChessboardCorners(gray, CHECKERBOARD, cv2.CALIB_CB_ADAPTIVE_THRESH + cv2.CALIB_CB_FAST_CHECK + cv2.CALIB_CB_NORMALIZE_IMAGE)
	"""
	If desired number of corner are detected,
	we refine the pixel coordinates and display 
	them on the images of checker board
	"""
	if ret == True:
		objpoints.append(objp)
		# refining pixel coordinates for given 2d points.
		corners2 = cv2.cornerSubPix(gray, corners, (11,11),(-1,-1), criteria)
		imgpoints.append(corners2)

		# Draw and display the corners
		img = cv2.drawChessboardCorners(img,CHECKERBOARD,corners2,ret)

	cv2.imshow('img',img)
	cv2.waitKey(0)

cv2.destroyAllWindows()

#h,w = img.shape[:2]

"""
Performing camera calibration by 
passing the value of known 3D points (objpoints)
and corresponding pixel coordinates of the 
detected corners (imgpoints)
"""
ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, (w,h), None, None)

print("Camera matrix : \n")
print(mtx)
print("dist : \n")
print(dist)
print("rvecs : \n")
print(rvecs)
print("tvecs : \n")
print(tvecs)
