# OpenCV-Python教程:47.姿态估计

import cv2
import numpy as np
import glob

mtx, dist, _, _ = [X[i] for i in ('mtx', 'dist', 'rvecs', 'tvecs')]

def draw(img, corners, imgpts):
corner = tuple(corners[0].ravel())
img = cv2.line(img, corner, tuple(imgpts[0].ravel()), (255,0,0), 5)
img = cv2.line(img, corner, tuple(imgpts[1].ravel()), (0,255,0), 5)
img = cv2.line(img, corner, tuple(imgpts[2].ravel()), (0,0,255), 5)
return img

criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 30, 0.001)
objp = np.zeros((6*7, 3), np.float32)
objp[:,:2] = np.mgrid[0:7,0:6].T.reshape(-1,2)
axis = np.float32([[3,0,0], [0,3,0], [0,0,-3]]).reshape(-1,3)

for fname in glob.glob('left*.jpg'):
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
ret, corners = cv2.findChessboardCorners(gray, (7,6),None)

if ret == True:
corners2 = cv2.cornerSubPix(gray,corners,(11,11),(-1,-1),criteria)

# Find the rotation and translation vectors.
rvecs, tvecs, inliers = cv2.solvePnPRansac(objp, corners2, mtx, dist)

# project 3D points to image plane
imgpts, jac = cv2.projectPoints(axis, rvecs, tvecs, mtx, dist)

img = draw(img,corners2,imgpts)
cv2.imshow('img',img)
k = cv2.waitKey(0) & 0xff
if k == 's':
cv2.imwrite(fname[:6]+'.png', img)

cv2.destroyAllWindows()

def draw(img, corners, imgpts):
imgpts = np.int32(imgpts).reshape(-1,2)

# draw ground floor in green
img = cv2.drawContours(img, [imgpts[:4]],-1,(0,255,0),-3)

# draw pillars in blue color
for i,j in zip(range(4),range(4,8)):
img = cv2.line(img, tuple(imgpts[i]), tuple(imgpts[j]),(255),3)

# draw top layer in red color
img = cv2.drawContours(img, [imgpts[4:]],-1,(0,0,255),3)

return img

axis = np.float32([[0,0,0], [0,3,0], [3,3,0], [3,0,0], [0,0,-3], [0,3,-3], [3,3,-3], [3,0,-3]])