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首页 > 解决方案 > 没有这样的文件或目录：在编译“pose_estimation.py”以使用 Opencv 绘制 3d 立方体时出现“B.npz”

python - 没有这样的文件或目录：在编译“pose_estimation.py”以使用 Opencv 绘制 3d 立方体时出现“B.npz”

问题描述

我想使用 Opencv 和 python 在棋盘的第一个角上绘制 3D 坐标轴（X、Y、Z 轴）。

但是当我运行以下代码时，

import cv2
import numpy as np
import glob

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

# Load previously saved data
with np.load('B.npz') as X:
    mtx, dist, _, _ = [X[i] for i in ('mtx','dist','rvecs','tvecs')]

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'):
    img = cv2.imread(fname)
    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()

我收到此错误：

Traceback (most recent call last):
  File "D:\3D Image Processing Dev Soft\Code\pose_estimation.py", line 13, in <module>
    with np.load('B.npz') as X:
  File "C:\Python27\lib\site-packages\numpy\lib\npyio.py", line 422, in load
    fid = open(os_fspath(file), "rb")
IOError: [Errno 2] No such file or directory: 'B.npz'

帮助我克服这个问题。谢谢你。

标签： pythonpython-2.7opencvopencv3.0

解决方案

为了生成B.npz文件，您应该在上一节np.savez()之后添加一些参数（mtx、和）dist，如下所示：rvecstvecscv.calibrateCamera()

for fname in images:
    img = cv.imread(fname)
    gray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)
    # Find the chess board corners
    ret, corners = cv.findChessboardCorners(gray, (7,6), None)
    # If found, add object points, image points (after refining them)
    if ret == True:
        objpoints.append(objp)
        corners2 = cv.cornerSubPix(gray,corners, (11,11), (-1,-1), criteria)
        imgpoints.append(corners)
        # Draw and display the corners
        cv.drawChessboardCorners(img, (7,6), corners2, ret)
        cv.imshow('img', img)
        cv.waitKey(500)

ret, mtx, dist, rvecs, tvecs = cv.calibrateCamera(objpoints, imgpoints, gray.shape[::-1], None, None)

np.savez('B.npz', mtx=mtx, dist=dist, rvecs=rvecs, tvecs=tvecs)

cv.destroyAllWindows()

顺便说一句，np.savez.npz将几个数组以未压缩格式保存到一个文件中。

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