92 lines
3.2 KiB
Python
92 lines
3.2 KiB
Python
import os
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import os.path as osp
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import glob
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import cv2 as cv
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import numpy as np
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import json
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import argparse
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def calibrate_camera(imgFolder, chessboardSize, squareSize):
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# 设置输出目录
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outputFolder = osp.join(imgFolder, "output")
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if not osp.exists(outputFolder):
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os.makedirs(outputFolder)
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# 图片路径
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imgPaths = []
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for extension in ["jpg", "png", "jpeg"]:
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imgPaths += glob.glob(osp.join(imgFolder, "*.{}".format(extension)))
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if len(imgPaths) == 0:
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print("No images found!")
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return
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# 存储世界坐标和像素坐标
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# 计算出棋盘格中每个网格角点的坐标，之后当成世界坐标
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board_w, board_h = chessboardSize
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board_grid = np.zeros((board_w * board_h, 3), np.float32)
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board_grid[:, :2] = np.mgrid[0:board_w, 0:board_h].T.reshape(-1, 2) * squareSize
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pointsWorld = []
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pointsPixel = []
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# 遍历图片
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for imgPath in imgPaths:
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img = cv.imread(imgPath)
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gray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)
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# 查找角点
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ret, corners = cv.findChessboardCorners(gray, (board_w, board_h), None)
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if ret:
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cv.cornerSubPix(gray, corners, (11, 11), (-1, -1), (cv.TERM_CRITERIA_EPS + cv.TERM_CRITERIA_MAX_ITER, 30, 0.001))
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pointsWorld.append(board_grid)
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pointsPixel.append(corners)
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cv.drawChessboardCorners(img, (board_w, board_h), corners, ret)
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cv.imwrite(osp.join(outputFolder, osp.basename(imgPath)), img)
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# 标定相机
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ret, mtx, dist, rvecs, tvecs = cv.calibrateCamera(pointsWorld, pointsPixel, gray.shape[::-1], None, None)
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print("Intrinsic matrix:\n", mtx.astype(np.float32))
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print("Distortion coefficients:\n", dist.astype(np.float32))
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# 计算重投影误差
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nimg = len(pointsWorld)
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img_error = np.zeros(nimg)
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for i in range(nimg):
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imgpoints2, _ = cv.projectPoints(pointsWorld[i], rvecs[i], tvecs[i], mtx, dist)
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error = cv.norm(pointsPixel[i], imgpoints2, cv.NORM_L2) / len(imgpoints2)
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img_error[i] = error
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good_img = np.where(img_error < 0.5)[0]
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mean_error = np.mean(img_error[good_img])
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print("Reprojection error: ", mean_error)
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# 挑选出重投影误差小于1.0的图片，重新标定相机
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if len(good_img) == 0:
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print("No images with error < 0.5")
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elif len(good_img) == nimg:
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print("All images have error < 0.5")
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pass
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else :
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pointsWorld2 = [pointsWorld[i] for i in good_img]
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pointsPixel2 = [pointsPixel[i] for i in good_img]
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ret, mtx, dist, rvecs, tvecs = cv.calibrateCamera(pointsWorld2, pointsPixel2, gray.shape[::-1], None, None)
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print("Intrinsic matrix:\n", mtx.astype(np.float32))
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print("Distortion coefficients:\n", dist.astype(np.float32))
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return mtx, dist
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def write_json_data(mtx, dist, outputFolder):
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data = {
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"intrinsic_matrix": mtx.tolist(),
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"distortion_coefficients": dist.tolist()
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}
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with open(osp.join(outputFolder, "calibration.json"), "w") as f:
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json.dump(data, f, indent=4)
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if __name__ == "__main__":
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mtx, dist = calibrate_camera("./test/intri_imgs", (11, 8), 60)
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write_json_data(mtx, dist, "./test/intri_imgs/output")
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