python相机标定流程图_Python图像处理 —— 相机标定、畸变矫正

实验数据

标定图(黑白棋盘图)若干(不少于10张拍摄不同角度的图片，焦距不变)

过程

每张图片提取角点信息

每张图片提取亚像素角点信息

相机标定

畸变矫正

内参数矩阵、畸变系数

这里保存为json文件

{

"mtx": [

[

3096.855023641478,

0.0,

1029.4641305618723

],

[

0.0,

3091.0248015384295,

333.24889640636945

],

[

0.0,

0.0,

1.0

]

],

"dist": [

[

-0.102230276138444,

-6.080581251041141,

0.013564529498038387,

-0.0027957254737596593,

39.277124343630284

]

]

}

矫正前图像

矫正后图像

代码

包括图片矫正、视频矫正

import os

import cv2

import glob

import json

import numpy as np

class CameraCalibration:

def calibration_init(self, width, height, pic_path, save_parameters=True):

# 亚像素角点的参数

criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 30, 0.001)

# 标定板角点的位置

objp = np.zeros((width * height, 3), np.float32)

objp[:, :2] = np.mgrid[0:width, 0:height].T.reshape(-1, 2)

# 存储点

obj_points, img_points = [], []

images = glob.glob(pic_path)

for i in images:

img = cv2.imread(i)

gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

# 棋盘格角点

ret, corners = cv2.findChessboardCorners(gray, (width, height), None)

# 存储角点

if ret:

cv2.cornerSubPix(gray, corners, (11, 11), (-1, -1), criteria)

obj_points.append(objp)

img_points.append(corners)

# 标定

ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(obj_points, img_points, gray.shape[::-1], None, None)

if save_parameters:

self.__parameters_init(mtx, dist)

else:

print("ret:", ret)

print("mtx:\n", mtx) # 内参数矩阵

print("dist:\n", dist) # 畸变系数 distortion cofficients = (k_1,k_2,p_1,p_2,k_3)

print("rvecs:\n", rvecs) # 旋转向量 # 外参数

print("tvecs:\n", tvecs) # 平移向量 # 外参数

def __parameters_init(self, mtx, dist):

parameters_path = './parameters.json'

if not os.path.exists(parameters_path):

os.system(r'touch %s' % parameters_path)

self.__write_parameters(mtx, dist)

else:

self.__write_parameters(mtx, dist)

@staticmethod

def __write_parameters(mtx, dist):

with open("./parameters.json", "w", encoding='utf-8') as f:

content = {"mtx": mtx.tolist(), "dist": dist.tolist()}

f.write(json.dumps(content, ensure_ascii=False))

f.close()

class CameraCorrect:

def __init__(self):

self.__correct_init()

# 畸变参数初始化

def __correct_init(self, parameters_file_path: str = "./parameters.json"):

if not os.path.exists(parameters_file_path):

pass

else:

with open(parameters_file_path, "r", encoding='utf-8') as f:

json_data = json.load(f)

self.mtx = np.array(json_data["mtx"])

self.dist = np.array(json_data["dist"])

# 图片畸变校准

def correct_pic(self, origin_path: str, target_path: str = "./", file_name: str = "cor_pic",

file_format: str = "png"):

img = cv2.imread(origin_path)

pic_height, pic_width = img.shape[:2]

file_format = self.__calibration_pic_format(file_format.lower())

cv2.imwrite(target_path + file_name + "." + file_format,

self.__distortion_correction(img, pic_width, pic_height))

# 视频畸变校准(直接输出视频)

def correct_vid2vid(self, origin_path: str, target_path: str = "./", file_name: str = "cor_vid",

file_format: str = "mp4", file_coding: str = "mp4v"):

cap = cv2.VideoCapture(origin_path)

# 获取视频参数

fps, count, vid_width, vid_height = self.__get_capture_attribute(cap)

# 格式编码校对

if self.__calibration_format_coding(file_format, file_coding) is False:

file_format, file_coding = "mp4", "mp4v"

out = cv2.VideoWriter(target_path + file_name + "." + file_format,

cv2.VideoWriter_fourcc(*self.__get_vid_coding(file_coding)), fps,

(vid_width, vid_height))

for i in range(count):

ret, img = cap.read()

if ret:

img = cv2.resize(img, (vid_width, vid_height))

dst = self.__distortion_correction(img, vid_width, vid_height)

out.write(dst)

cap.release()

out.release()

# 视频畸变校准(校准抽取所有帧)

def correct_vid2pic(self, origin_path: str, target_path: str = "./", file_name: str = "cor_pic",

file_format: str = "png"):

file_format = self.__calibration_pic_format(file_format.lower())

cap = cv2.VideoCapture(origin_path)

fps, count, vid_width, vid_height = self.__get_capture_attribute(cap)

for i in range(count):

ret, img = cap.read()

if ret:

img = cv2.resize(img, (vid_width, vid_height))

cv2.imwrite(target_path + file_name + "_" + str(i) + "." + file_format,

self.__distortion_correction(img, vid_width, vid_height))

cap.release()

cv2.destroyAllWindows()

# 获取视频参数

@staticmethod

def __get_capture_attribute(vid: cv2.VideoCapture):

fps = int(vid.get(cv2.CAP_PROP_FPS)) # 视频帧率

count = int(vid.get(cv2.CAP_PROP_FRAME_COUNT)) # 视频帧数

width = int(vid.get(cv2.CAP_PROP_FRAME_WIDTH)) # 视频宽度 vid.shape[1]

height = int(vid.get(cv2.CAP_PROP_FRAME_HEIGHT)) # 视频高度 vid.shape[0]

return fps, count, width, height

# 图片格式校对

@staticmethod

def __calibration_pic_format(file_format: str):

if file_format == "jpg" or file_format == "png" or file_format == "bmp" or file_format == "tiff" or file_format == "tif":

return file_format

else:

return "png"

# 视频格式编码校对

@staticmethod

def __calibration_format_coding(file_format: str, file_coding: str):

file_format, file_coding = file_format.lower(), file_coding.lower()

if file_format == "mp4" and file_coding == "mp4v":

return True

elif file_format == "avi" and (file_coding == "yuv" or file_coding == "mpeg-1" or file_coding == "mpeg-4"):

return True

elif file_format == "ogv" and file_coding == "ogg vorbis":

return True

elif file_format == "flv" and file_coding == "flash":

return True

else:

return False

# 获取编码参数

@staticmethod

def __get_vid_coding(file_coding: str):

file_coding = file_coding.lower()

if file_coding == "mp4v":

return 'mp4v'

elif file_coding == "yuv":

return 'I420'

elif file_coding == "mpeg-1":

return 'PIMI'

elif file_coding == "mp4g-4":

return 'XVID'

elif file_coding == "ogg vorbis":

return 'THEO'

elif file_coding == "flash":

return 'FLV1'

else:

return 'mp4v'

# 畸变矫正

def __distortion_correction(self, img, origin_width, origin_height):

# 去畸变

new_camera_mtx, roi = cv2.getOptimalNewCameraMatrix(self.mtx, self.dist, (origin_width, origin_height), 0,

(origin_width, origin_height))

dst = cv2.undistort(img, self.mtx, self.dist, None, new_camera_mtx)

# 根据ROI区域裁剪图片

x, y, width, height = roi

dst = dst[y:y + height, x:x + width]

dst = cv2.resize(dst, (origin_width, origin_height))

return dst

if __name__ == '__main__':

cal = CameraCalibration()

cal.calibration_init(9, 6, "./pic/*.jpg")

cor = CameraCorrect()

cor.correct_pic("./pic/cm_flag_5.jpg", "./output_pic/")

cor.correct_vid2vid("./vid/vid_demo_1.mp4", "./output_vid/")

cor.correct_vid2pic("./vid/vid_demo_1.mp4", "./output_vid/")