import numpy as np

import cv2

cap = cv2.VideoCapture(0)

_DEFAULT_SENSOR_SIZE = (6.0, 4.8) # mm

#Rotation Vector

rvec = np.array([0, 0, 0], np.float)

# Translation Vector

tvec = np.array([0, 0, 0], np.float)

# fx and fy are the focal lengths expressed in pixel units.

fx = fy = 1.0

# (cx,cy) is a principal point that is usually at the image center.

cx = cy = 0.0

cameraMatrix = np.array([[fx, 0, cx], [0, fy, cy], [0, 0, 1]])

ret, frame = cap.read()

[rows, cols, channels] = frame.shape

aperture = _DEFAULT_SENSOR_SIZE

# print('aperture_width:',aperture[0])

# print('aperture_height:',aperture[1])

fov_x, fov_y, focal_len, principal, aspect = \

cv2.calibrationMatrixValues(cameraMatrix, (cols,rows),

aperture[0], aperture[1])

print('fov_x:',fov_x)

print('fov_y:',fov_y)

print('focal length',focal_len)

print('principal:',principal)

print('aspect:',aspect)

# while(True):

# # Capture frame-by-frame

# ret, frame = cap.read()

#

# # Our operations on the frame come here

# # gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

#

# # Display the resulting frame

# cv2.imshow('frame',frame)

# if cv2.waitKey(1) & 0xFF == ord('q'):

# break

#

# # When everything done, release the capture

# cap.release()

# cv2.destroyAllWindows()