PnP(Perspective-n-Point)是求解3D到2D点的对应方法。不论是相机和雷达的标定还是相机和相机的标定都可以使用PNP来解决,即通过不同坐标系下相同的点对求解变换矩阵。
这里相机多用棋盘格中的角点来实现点的提取。流行方法为张正友标定法,至于详细原理可点击我的博客https://www.cnblogs.com/tangjunjun/p/16240878.html查看,本博客主要使用代码
实现外参求解与相机标定的内参和畸变系数求解。
 
 
代码及标定图链接:https://pan.baidu.com/s/1ujX19IUV0EPSIMyIcBnClA?pwd=r63z   (相机标定与外参求解.zip文件)
      提取码:r63z
 
①相机标定,求解内参与畸变系数;
# 相机标定,主要求内参和畸变系数
def calibration_camera(img_root, rand_count=20):
    board_h = 8
    board_w = 11
    objp = np.zeros((board_h * board_w, 3), np.float32)
    objp[:, :2] = np.mgrid[0:board_w, 0:board_h].T.reshape(-1, 2)  # 将世界坐标系建在标定板上,所有点的Z坐标全部为0,所以只需要赋值x和y
    objp = 60 * objp  # 打印棋盘格一格的边长为2.6cm
    obj_points = []  # 存储3D点
    img_points = []  # 存储2D点
    images = glob.glob(os.path.join(img_root, '*.jpg'))  # 黑白棋盘的图片路径
    random.shuffle(images)
    if rand_count > len(images):
        rand_count = len(images)

    for fname in images[:rand_count]:
        img = cv2.imread(fname)
        gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
        size = gray.shape[::-1]
        ret, corners = cv2.findChessboardCorners(gray, (board_w, board_h), None)
        if ret:
            obj_points.append(objp)
            corners2 = cv2.cornerSubPix(gray, corners, (5, 5), (-1, -1),
                                        (cv2.TERM_CRITERIA_MAX_ITER | cv2.TERM_CRITERIA_EPS, 30, 0.001))
            if [corners2]:
                img_points.append(corners2)
            else:
                img_points.append(corners)
            cv2.drawChessboardCorners(img, (board_w, board_h), corners, ret)  # 记住,OpenCV的绘制函数一般无返回值
            cv2.imshow("img", img)
            cv2.waitKey(10)
    ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(obj_points, img_points, size, None, None)
    # v_rot_mat, _ = cv2.Rodrigues(np.array(v_rot).reshape(-1))
    # print("旋转矩阵=", v_rot_mat)
    # print("内参=", mtx)
    # print("畸变系数=", dist)
    # print("旋转向量=", rvecs)
    # print("平移向量=", tvecs)

    # 反投影误差
    total_error = 0
    for i in range(len(obj_points)):
        imgpoints2, _ = cv2.projectPoints(obj_points[i], rvecs[i], tvecs[i], mtx, dist)
        error = cv2.norm(img_points[i], imgpoints2, cv2.NORM_L2) / len(imgpoints2)
        total_error += error
    # print("total error: ", total_error / len(obj_points))
    return mtx, dist, total_error

 

②通过畸变系数矫正,获得矫正的图像;
# 消除畸变
def revise_img(img_root, mtx, dist):
    mtx = np.array(mtx)
    dist = np.array(dist).reshape(1, 5)
    img = cv2.imread(img_root)
    h, w = img.shape[:2]
    newcameramtx, roi = cv2.getOptimalNewCameraMatrix(mtx, dist, (w, h), 1, (w, h))
    # undistort
    dst = cv2.undistort(img, mtx, dist, None, newcameramtx)
    # crop the image
    x, y, w, h = roi
    dst = dst[y:y + h, x:x + w]
    cv2.imwrite('./revise_img.jpg', dst)
    return dst
③使用PnP方法求解外参;
# 旋转向量和平移向量求解
def calibration_RT(points_3D, points_2D, cameraMatrix, distCoeffs):
    points_3D = np.array(points_3D)
    points_2D = np.array(points_2D)
    cameraMatrix = np.array(cameraMatrix).astype(np.float32)
    distCoeffs = np.array(distCoeffs).astype(np.float32)
    _, rvecs, tvecs, inliers = cv2.solvePnPRansac(points_3D.reshape(-1, 1, 3),
                                                  points_2D.reshape(-1, 1, 2),
                                                  cameraMatrix,
                                                  distCoeffs
                                                  )
    R, _ = cv2.Rodrigues(rvecs)
    print('R:\n', R)
    print('rvecs:\n', rvecs)
    print('tvecs:\n', tvecs)

    return R, tvecs

 

④附带三点对应求解空间变换的旋转向量(矩阵)和平移向量(主要记录此方法);
 
def rigid_transform_RT(lidarPoints, rtkPoints):
    '''
    :param lidarPoints: 世界坐标系<---原始坐标,需要转换的坐标系
    :param rtkPoints:  目标世界坐标系<---目标三维坐标,已转换的坐标
    :return:
    # Input: expects Nx3 matrix of points
    # Returns R,t
    # R = 3x3 rotation matrix
    # t = 3x1 column vector
    demo:
    rigid_transform_RT(L1,S1)

    '''
    Pa = np.array(lidarPoints)
    Pb = np.array(rtkPoints)
    N = Pa.shape[0]  # total points

    centroid_Pa = np.mean(Pa, axis=0)
    centroid_Pb = np.mean(Pb, axis=0)

    # centre the points
    H_Pa = Pa - np.tile(centroid_Pa, (N, 1))
    H_Pb = Pb - np.tile(centroid_Pb, (N, 1))

    H = np.matmul(np.transpose(H_Pa), H_Pb)
    U, S, V = np.linalg.svd(H)
    R = np.matmul(V.T, U.T)

    if np.linalg.det(R) < 0:
        print("det(R) < R, reflection detected!, correcting for it ...\n")
        V[2, :] *= -1
        R = np.matmul(V.T, U.T)

    T = centroid_Pb - np.matmul(R, centroid_Pa)
    print("R:\n{}\nT:\n{}".format(R, T))
    return R, T

 

以上为世界坐标系转到像素坐标系方法的代码,以下代码为整体代码: 
import numpy as np
import os
import cv2
import glob
# *******************utils*********************#
import matplotlib.pyplot as plt
import random


def draw_circle(img, coord):
    coord = np.array(coord).reshape(-1)
    cv2.circle(img, (int(coord[0]), int(coord[1])), 2, (0, 0, 255), -1)
    return img

def draw_axis(img, O, OX, OY, OZ):
    color = (0, 0, 255)
    frontsize = 0.5
    img = cv2.line(img, (int(O[0]), int(O[1])), (int(OX[0]), int(OX[1])), color, 1)
    cv2.putText(img, 'X', (int(OX[0]), int(OX[1])), cv2.FONT_HERSHEY_SIMPLEX, frontsize, color, 1)

    img = cv2.line(img, (int(O[0]), int(O[1])), (int(OY[0]), int(OY[1])), color, 1)
    cv2.putText(img, 'Y', (int(OY[0]), int(OY[1])), cv2.FONT_HERSHEY_SIMPLEX, frontsize, color, 1)
    img = cv2.line(img, (int(O[0]), int(O[1])), (int(OZ[0]), int(OZ[1])), color, 1)
    cv2.putText(img, 'Z', (int(OZ[0]), int(OZ[1])), cv2.FONT_HERSHEY_SIMPLEX, frontsize, color, 1)
    return img


def show_img(img):
    plt.imshow(img)
    plt.show()


# *******************************通过内参联合求解外参*******************#

def get_pixel(coord, mtx, R, T):
    mtx = np.array(mtx)
    R = np.array(R)
    T = np.array(T).reshape(3, 1)
    coord = np.array(coord).reshape(-1, 1)

    RT = np.hstack((R, T))
    XYZ_camera = np.matmul(RT, coord)
    # XYZ_camera = XYZ_camera / XYZ_camera[-1, -1]
    x, y, z = np.matmul(mtx, XYZ_camera)
    x = x / z
    y = y / z

    print('x={}\ty={}'.format(x[0], y[0]))
    return [x[0], y[0]]


# ***********************利用opencv相机标定**************#

# 相机标定,主要求内参和畸变系数
def calibration_camera(img_root, rand_count=20):
    board_h = 8
    board_w = 11
    objp = np.zeros((board_h * board_w, 3), np.float32)
    objp[:, :2] = np.mgrid[0:board_w, 0:board_h].T.reshape(-1, 2)  # 将世界坐标系建在标定板上,所有点的Z坐标全部为0,所以只需要赋值x和y
    objp = 60 * objp  # 打印棋盘格一格的边长为2.6cm
    obj_points = []  # 存储3D点
    img_points = []  # 存储2D点
    images = glob.glob(os.path.join(img_root, '*.jpg'))  # 黑白棋盘的图片路径
    random.shuffle(images)
    if rand_count > len(images):
        rand_count = len(images)

    for fname in images[:rand_count]:
        img = cv2.imread(fname)
        gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
        size = gray.shape[::-1]
        ret, corners = cv2.findChessboardCorners(gray, (board_w, board_h), None)
        if ret:
            obj_points.append(objp)
            corners2 = cv2.cornerSubPix(gray, corners, (5, 5), (-1, -1),
                                        (cv2.TERM_CRITERIA_MAX_ITER | cv2.TERM_CRITERIA_EPS, 30, 0.001))
            if [corners2]:
                img_points.append(corners2)
            else:
                img_points.append(corners)
            cv2.drawChessboardCorners(img, (board_w, board_h), corners, ret)  # 记住,OpenCV的绘制函数一般无返回值
            cv2.imshow("img", img)
            cv2.waitKey(10)
    ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(obj_points, img_points, size, None, None)
    # v_rot_mat, _ = cv2.Rodrigues(np.array(v_rot).reshape(-1))
    # print("旋转矩阵=", v_rot_mat)
    # print("内参=", mtx)
    # print("畸变系数=", dist)
    # print("旋转向量=", rvecs)
    # print("平移向量=", tvecs)

    # 反投影误差
    total_error = 0
    for i in range(len(obj_points)):
        imgpoints2, _ = cv2.projectPoints(obj_points[i], rvecs[i], tvecs[i], mtx, dist)
        error = cv2.norm(img_points[i], imgpoints2, cv2.NORM_L2) / len(imgpoints2)
        total_error += error
    # print("total error: ", total_error / len(obj_points))
    return mtx, dist, total_error


# 旋转向量和平移向量求解
def calibration_RT(points_3D, points_2D, cameraMatrix, distCoeffs):
    points_3D = np.array(points_3D)
    points_2D = np.array(points_2D)
    cameraMatrix = np.array(cameraMatrix).astype(np.float32)
    distCoeffs = np.array(distCoeffs).astype(np.float32)
    _, rvecs, tvecs, inliers = cv2.solvePnPRansac(points_3D.reshape(-1, 1, 3),
                                                  points_2D.reshape(-1, 1, 2),
                                                  cameraMatrix,
                                                  distCoeffs
                                                  )
    R, _ = cv2.Rodrigues(rvecs)
    print('R:\n', R)
    print('rvecs:\n', rvecs)
    print('tvecs:\n', tvecs)

    return R, tvecs


def get_calibration_pixel(coord, rvecs, tvecs, mtx, dist):
    imgpts, jac = cv2.projectPoints(coord, rvecs, tvecs, mtx, dist)
    return imgpts


# 消除畸变
def revise_img(img_root, mtx, dist):
    mtx = np.array(mtx)
    dist = np.array(dist).reshape(1, 5)
    img = cv2.imread(img_root)
    h, w = img.shape[:2]
    newcameramtx, roi = cv2.getOptimalNewCameraMatrix(mtx, dist, (w, h), 1, (w, h))
    # undistort
    dst = cv2.undistort(img, mtx, dist, None, newcameramtx)
    # crop the image
    x, y, w, h = roi
    dst = dst[y:y + h, x:x + w]
    cv2.imwrite('./revise_img.jpg', dst)
    return dst


# 自动寻找3d点与像素点对应坐标(只针对标定版)
def find_point_3d2d(img_root, save=True):
    board_h = 8
    board_w = 11
    objp = np.zeros((board_h * board_w, 3), np.float32)
    objp[:, :2] = np.mgrid[0:board_w, 0:board_h].T.reshape(-1, 2)  # 将世界坐标系建在标定板上,所有点的Z坐标全部为0,所以只需要赋值x和y
    points_3d = 60 * objp  # 打印棋盘格一格的边长为2.6cm
    points_2d = None  # 存储2D点
    img = cv2.imread(img_root)
    img_rand = img.copy()
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    rand_p2, rand_p3 = None, None
    ret, corners = cv2.findChessboardCorners(gray, (board_w, board_h), None)
    print('ret=', ret)
    if ret:

        corners = cv2.cornerSubPix(gray, corners, (5, 5), (-1, -1),
                                   (cv2.TERM_CRITERIA_MAX_ITER | cv2.TERM_CRITERIA_EPS, 30, 0.001))

        cv2.drawChessboardCorners(img, (board_w, board_h), corners, ret)  # 记住,OpenCV的绘制函数一般无返回值

        points_2d = corners.reshape(-1, 2)

        if save:
            file_write_obj = open('./save_points_3d2d.txt', 'w', encoding='utf-8')  # 以写的方式打开文件,如果文件不存在,就会自动创建
            for i, p2 in enumerate(points_2d):
                text = '3d:\t' + str(points_3d[i]) + '\t2d\t' + str(p2) + '\n'
                file_write_obj.writelines(text)
            k = 10
            rand_int = random.sample(range(1, len(points_2d)), k)

            # print('rand_int=',rand_int)
            rand_int = [48, 55, 85, 22, 73, 39, 68, 31, 78, 71]
            rand_p2 = points_2d[rand_int]
            rand_p3 = points_3d[rand_int]
            file_write_obj.close()
            # 图像展示选择坐标点
            for inds in rand_int:
                pp2 = points_2d[inds]
                img_rand = draw_circle(img_rand, pp2)
            cv2.imwrite('./calibration_point.jpg', img_rand)

        show_img(img)

    return points_3d, points_2d, rand_p3, rand_p2


def draw_board(img_root, mtx, R, T, dist=None):
    img = cv2.imread(img_root)
    mtx = np.array(mtx)
    dist = np.array(dist).reshape(1, 5) if dist is not None else None
    for i in range(10):
        for j in range(8):
            coord = [i * 60, j * 60, 0.0, 1]
            coord = np.array(coord)
            coord_pixel = get_pixel(coord, mtx, R, T)
            RMat = cv2.Rodrigues(R)[0]
            coord = [[i * 60, j * 60, 0.0]]
            # coord_pixel, _ = cv2.projectPoints(coord,RMat, T, mtx, dist)
            img = draw_circle(img, coord_pixel)
    # # 画坐标轴
    L = 80
    O = get_pixel([0, 0, 0, 1], mtx, R, T)
    OX = get_pixel([L, 0, 0, 1], mtx, R, T)
    OY = get_pixel([0, L, 0, 1], mtx, R, T)
    OZ = get_pixel([0, 0, L, 1], mtx, R, T)
    img = draw_axis(img, O, OX, OY, OZ)

    show_img(img)
    cv2.imwrite('./predict_result.jpg', img)


def draw_space(img_root, coord, mtx, R, T):
    img = cv2.imread(img_root)

    for c in coord:
        c = np.array(c)
        coord_pixel = get_pixel(c, mtx, R, T)

        img = draw_circle(img, coord_pixel)
    # # 画坐标轴
    L = 2
    O = get_pixel([0, 0, 0, 1], mtx, R, T)
    OX = get_pixel([L, 0, 0, 1], mtx, R, T)
    OY = get_pixel([0, L, 0, 1], mtx, R, T)
    OZ = get_pixel([0, 0, L, 1], mtx, R, T)
    img = draw_axis(img, O, OX, OY, OZ)

    show_img(img)
    cv2.imwrite('./predict_result.jpg', img)


def get_coord(M=6, N=15):
    # M, N = 6, 15  # 行与列
    coord_size = 1
    coord = []
    for i in range(M):
        for j in range(N):
            coord.append([i * coord_size, j * coord_size, 0, 1])
    # for i in [-1, -2, -3, -4]:
    #     for j in range(N):
    #         coord.append([i * coord_size, j * coord_size, 0, 1])
    return coord





if __name__ == '__main__':

    predict_space = False  # 实际空间坐标标定
    predict_board = False  # 决定测试标定版输出结果
    calibration = True
    if calibration:
        img_root = r'C:\Users\vrc\Desktop\RadarCamera\code\camera_main\data\data09206\img_ori'

        mtx_best, dist_best, total_error_best = None, None, 100000
        for i in range(50):
            mtx, dist, total_error = calibration_camera(img_root, rand_count=14)
            if total_error < total_error_best:
                total_error_best = total_error
                mtx_best = mtx
                dist_best = dist
                print("最小误差=", total_error_best)
        print("最优内参=", mtx_best)
        print("最优畸变系数=", dist_best)
        print("最小误差=", total_error_best)

    mtx = [[1.90555223e+03, 0.00000000e+00, 1.01084265e+03],
           [0.00000000e+00, 1.89395850e+03, 5.29217920e+02],
           [0.00000000e+00, 0.00000000e+00, 1.00000000e+00]]
    dist = [-0.39262705, 0.16798904, -0.00529946, 0.0008667, -0.37552875]

    if predict_board:
        #只针对标定板
        img_root = r'C:\Users\vrc\Desktop\RadarCamera\data\phone\2.jpg'
        img = revise_img(img_root, mtx, dist)
        img_root = './revise_img.jpg'
        _, _, rand_p3, rand_p2 = find_point_3d2d(img_root)

        # dist = [0, 0, 0, 0, 0]
        R, T = calibration_RT(rand_p3, rand_p2, mtx, dist)

        # 通过内外参求解像素坐标
        # img_root = './revise_img.jpg'

        draw_board(img_root, mtx, R, T, dist=dist)
    if predict_space:
        img_root = r'C:\Users\vrc\Desktop\RadarCamera\code\camera_main\data\data0926-2\1.png'
        img = revise_img(img_root, mtx, dist)
        img_root = './revise_img.jpg'

        p3 = [[1, 1, 0], [0.0, 3, 0], [2, 2.0, 0], [1, 5, 0], [2, 1, 0]]
        p2 = [[939.0, 462], [702.0, 234], [1239, 344], [947, 134], [1312, 478]]

        dist = [0, 0, 0, 0, 0]
        R, T = calibration_RT(p3, p2, mtx, dist)

        # coord = [[1, 3.0, 0, 1], [4, 5, 0, 1], [2, 6, 0, 1], [2,  2,0, 1], [-1, 4, 0, 1]]
        coord = get_coord(M=3, N=15)
        draw_space(img_root, coord, mtx, R, T)

 

世界坐标系转像素结果展示:

添加验证场景(2022-0929):

 添加场景一:

添加场景二:

 

 介绍cv2.projectPoints函数,该函数可以将世界坐标系转为对应原始图像像素坐标系,无需上面那样矫正。

imgpts, jac = cv2.projectPoints(coord, rvecs, tvecs, mtx, dist)

参数格式如下图:

 其中mtx与dist分别为相机标定求解的内参与畸变系数,rvecs与tvecs为旋转向量和平移向量,即为外参,返回imgpts坐标为

原始图像坐标(未矫正的坐标)。

 我也将直接使用原始图像求解代码直接粘贴此处:

import numpy as np
import os
import cv2
import glob
# *******************utils*********************#
import matplotlib.pyplot as plt
import random
import shutil


def draw_circle(img, coord):
    coord = np.array(coord).reshape(-1)
    try:
        cv2.circle(img, (int(coord[0]), int(coord[1])), 2, (0, 0, 255), -1)
    except:
        pass
    return img


def build_dir(root):
    import os
    if not os.path.exists(root):
        os.makedirs(root)
    return root


def draw_axis(img, O, OX, OY, OZ):
    color = (0, 255, 0)
    frontsize = 0.5
    img = cv2.line(img, (int(O[0]), int(O[1])), (int(OX[0]), int(OX[1])), color, 1)
    cv2.putText(img, 'X', (int(OX[0]), int(OX[1])), cv2.FONT_HERSHEY_SIMPLEX, frontsize, color, 1)

    img = cv2.line(img, (int(O[0]), int(O[1])), (int(OY[0]), int(OY[1])), color, 1)
    cv2.putText(img, 'Y', (int(OY[0]), int(OY[1])), cv2.FONT_HERSHEY_SIMPLEX, frontsize, color, 1)
    img = cv2.line(img, (int(O[0]), int(O[1])), (int(OZ[0]), int(OZ[1])), color, 1)
    cv2.putText(img, 'Z', (int(OZ[0]), int(OZ[1])), cv2.FONT_HERSHEY_SIMPLEX, frontsize, color, 1)
    return img


def show_img(img):
    plt.imshow(img)
    plt.show()


# *******************************通过内参联合求解外参*******************#

def get_pixel(coord, mtx, R, T):
    mtx = np.array(mtx)
    R = np.array(R)
    T = np.array(T).reshape(3, 1)
    coord = np.array(coord).reshape(-1, 1)

    RT = np.hstack((R, T))
    XYZ_camera = np.matmul(RT, coord)
    # XYZ_camera = XYZ_camera / XYZ_camera[-1, -1]
    x, y, z = np.matmul(mtx, XYZ_camera)
    x = x / z
    y = y / z

    # print('x={}\ty={}'.format(x[0], y[0]))
    return [x[0], y[0]]


# ***********************利用opencv相机标定**************#

# 相机标定,主要求内参和畸变系数
def calibration_camera(img_root, rand_count=6):
    board_h = 8
    board_w = 11
    objp = np.zeros((board_h * board_w, 3), np.float32)
    objp[:, :2] = np.mgrid[0:board_w, 0:board_h].T.reshape(-1, 2)  # 将世界坐标系建在标定板上,所有点的Z坐标全部为0,所以只需要赋值x和y
    objp = 60 * objp  # 打印棋盘格一格的边长为2.6cm
    obj_points = []  # 存储3D点
    img_points = []  # 存储2D点
    images = glob.glob(os.path.join(img_root, '*.jpg'))  # 黑白棋盘的图片路径
    random.shuffle(images)
    if rand_count > len(images):
        rand_count = len(images)

    for fname in images[:rand_count]:
        img = cv2.imread(fname)
        gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
        size = gray.shape[::-1]
        ret, corners = cv2.findChessboardCorners(gray, (board_w, board_h), None)
        if ret:
            obj_points.append(objp)
            corners2 = cv2.cornerSubPix(gray, corners, (5, 5), (-1, -1),
                                        (cv2.TERM_CRITERIA_MAX_ITER | cv2.TERM_CRITERIA_EPS, 30, 0.001))
            if [corners2]:
                img_points.append(corners2)
            else:
                img_points.append(corners)
            cv2.drawChessboardCorners(img, (board_w, board_h), corners, ret)  # 记住,OpenCV的绘制函数一般无返回值
            cv2.imshow("img", img)
            cv2.waitKey(10)
    ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(obj_points, img_points, size, None, None)
    # v_rot_mat, _ = cv2.Rodrigues(np.array(v_rot).reshape(-1))
    # print("旋转矩阵=", v_rot_mat)
    # print("内参=", mtx)
    # print("畸变系数=", dist)
    # print("旋转向量=", rvecs)
    # print("平移向量=", tvecs)

    # 反投影误差
    total_error = 0
    for i in range(len(obj_points)):
        imgpoints2, _ = cv2.projectPoints(obj_points[i], rvecs[i], tvecs[i], mtx, dist)
        error = cv2.norm(img_points[i], imgpoints2, cv2.NORM_L2) / len(imgpoints2)
        total_error += error
    # print("total error: ", total_error / len(obj_points))
    return mtx, dist, total_error


# 旋转向量和平移向量求解
def calibration_RT(points_3D, points_2D, cameraMatrix, distCoeffs):
    points_3D = np.array(points_3D)
    points_2D = np.array(points_2D)
    cameraMatrix = np.array(cameraMatrix).astype(np.float32)
    distCoeffs = np.array(distCoeffs).astype(np.float32)
    _, rvecs, tvecs, inliers = cv2.solvePnPRansac(points_3D.reshape(-1, 1, 3),
                                                  points_2D.reshape(-1, 1, 2),
                                                  cameraMatrix,
                                                  distCoeffs
                                                  )
    R, _ = cv2.Rodrigues(rvecs)
    # print('R:\n', R)
    # print('rvecs:\n', rvecs)
    # print('tvecs:\n', tvecs)

    return R, rvecs, tvecs


def get_calibration_pixel(coord, rvecs, tvecs, mtx, dist):
    mtx = np.array(mtx)
    dist = np.array(dist).reshape(1, 5)
    imgpts, jac = cv2.projectPoints(coord, rvecs, tvecs, mtx, dist)
    return imgpts


# 消除畸变
def revise_img(img_root, mtx, dist):
    mtx = np.array(mtx)
    dist = np.array(dist).reshape(1, 5)
    img = cv2.imread(img_root)
    h, w = img.shape[:2]
    newcameramtx, roi = cv2.getOptimalNewCameraMatrix(mtx, dist, (w, h), 1, (w, h))
    # undistort
    dst = cv2.undistort(img, mtx, dist, None, newcameramtx)
    # crop the image
    x, y, w, h = roi
    dst = dst[y:y + h, x:x + w]
    cv2.imwrite('./revise_img.jpg', dst)
    return dst


# 自动寻找3d点与像素点对应坐标(只针对标定版)
def find_point_3d2d(img_root, save=True):
    board_h = 8
    board_w = 11
    objp = np.zeros((board_h * board_w, 3), np.float32)
    objp[:, :2] = np.mgrid[0:board_w, 0:board_h].T.reshape(-1, 2)  # 将世界坐标系建在标定板上,所有点的Z坐标全部为0,所以只需要赋值x和y
    points_3d = 60 * objp  # 打印棋盘格一格的边长为2.6cm
    points_2d = None  # 存储2D点
    img = cv2.imread(img_root)
    img_rand = img.copy()
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    rand_p2, rand_p3 = None, None
    ret, corners = cv2.findChessboardCorners(gray, (board_w, board_h), None)
    print('ret=', ret)
    if ret:

        corners = cv2.cornerSubPix(gray, corners, (5, 5), (-1, -1),
                                   (cv2.TERM_CRITERIA_MAX_ITER | cv2.TERM_CRITERIA_EPS, 30, 0.001))

        cv2.drawChessboardCorners(img, (board_w, board_h), corners, ret)  # 记住,OpenCV的绘制函数一般无返回值

        points_2d = corners.reshape(-1, 2)

        if save:
            file_write_obj = open('./save_points_3d2d.txt', 'w', encoding='utf-8')  # 以写的方式打开文件,如果文件不存在,就会自动创建
            for i, p2 in enumerate(points_2d):
                text = '3d:\t' + str(points_3d[i]) + '\t2d\t' + str(p2) + '\n'
                file_write_obj.writelines(text)
            k = 10
            rand_int = random.sample(range(1, len(points_2d)), k)

            # print('rand_int=',rand_int)
            rand_int = [48, 55, 85, 22, 73, 39, 68, 31, 78, 71]
            rand_p2 = points_2d[rand_int]
            rand_p3 = points_3d[rand_int]
            file_write_obj.close()
            # 图像展示选择坐标点
            for inds in rand_int:
                pp2 = points_2d[inds]
                img_rand = draw_circle(img_rand, pp2)
            cv2.imwrite('./calibration_point.jpg', img_rand)

        show_img(img)

    return points_3d, points_2d, rand_p3, rand_p2


def draw_board(img_root, mtx, R, T, dist=None):
    img = cv2.imread(img_root)
    mtx = np.array(mtx)
    dist = np.array(dist).reshape(1, 5) if dist is not None else None
    for i in range(10):
        for j in range(8):
            coord = [i * 60, j * 60, 0.0, 1]
            coord = np.array(coord)
            coord_pixel = get_pixel(coord, mtx, R, T)
            RMat = cv2.Rodrigues(R)[0]
            coord = [[i * 60, j * 60, 0.0]]
            # coord_pixel, _ = cv2.projectPoints(coord,RMat, T, mtx, dist)
            img = draw_circle(img, coord_pixel)
    # # 画坐标轴
    L = 80
    O = get_pixel([0, 0, 0, 1], mtx, R, T)
    OX = get_pixel([L, 0, 0, 1], mtx, R, T)
    OY = get_pixel([0, L, 0, 1], mtx, R, T)
    OZ = get_pixel([0, 0, L, 1], mtx, R, T)
    img = draw_axis(img, O, OX, OY, OZ)

    show_img(img)
    cv2.imwrite('./predict_result.jpg', img)


def draw_space(img_root, coord, mtx, R, T):
    img = cv2.imread(img_root)

    for c in coord:
        c = np.array(c)
        coord_pixel = get_pixel(c, mtx, R, T)

        img = draw_circle(img, coord_pixel)
    # # 画坐标轴
    L = 2000
    O = get_pixel([0, 0, 0, 1], mtx, R, T)
    OX = get_pixel([L, 0, 0, 1], mtx, R, T)
    OY = get_pixel([0, L, 0, 1], mtx, R, T)
    OZ = get_pixel([0, 0, L, 1], mtx, R, T)
    img = draw_axis(img, O, OX, OY, OZ)

    show_img(img)
    cv2.imwrite('./predict_result.jpg', img)


def draw_space_new(img_root, coord, mtx, rvecs, tvecs, dist):
    img = cv2.imread(img_root)

    for c in coord:
        c = np.array(c)
        c = np.array([c[0], c[1], c[2]], dtype=np.float32)
        coord_pixel = get_calibration_pixel(c, rvecs, tvecs, mtx, dist)
        coord_pixel = coord_pixel.reshape(1, 2)
        img = draw_circle(img, coord_pixel)
    # # 画坐标轴
    L = 2000
    coord_pixel = get_calibration_pixel(np.array([0, 0, 0.0]), rvecs, tvecs, mtx, dist)
    O = coord_pixel.reshape(-1)
    coord_pixel = get_calibration_pixel(np.array([L, 0, 0.0]), rvecs, tvecs, mtx, dist)
    OX = coord_pixel.reshape(-1)
    coord_pixel = get_calibration_pixel(np.array([0, L, 0.0]), rvecs, tvecs, mtx, dist)
    OY = coord_pixel.reshape(-1)
    coord_pixel = get_calibration_pixel(np.array([0, 0.0, L]), rvecs, tvecs, mtx, dist)
    OZ = coord_pixel.reshape(-1)

    img = draw_axis(img, O, OX, OY, OZ)

    show_img(img)
    cv2.imwrite('./predict_result.jpg', img)


def get_coord(X_range=[-5,8], Y_range=[-3,15], coord_size=1):
    # M, N = 6, 15  # 行与列
    # coord_size = 1
    coord = []
    for i in list(range(X_range[0], X_range[1], 1)):
        for j in list(range(Y_range[0], Y_range[1], 1)):

            coord.append([i * coord_size+500, j * coord_size+500, 0, 1])



    return coord


def get_best_pnp_index(p3, p2, mtx, dist, N_pnp=4, loop_n=200):
    '''
    :param p3: 空间坐标
    :param p2: 图像坐标
    :param mtx: 内参
    :param dist: 畸变系数
    :param N_pnp: 决定多少个点求解pnp外参
    :param loop_n: 迭代次数
    :return: p3与p2对应中用于求解pnp的索引对应及最佳R与T
    '''
    N_p3 = N_pnp  # 设置选择计算pnp点数
    index = np.arange(len(p3))
    p3 = np.array(p3)
    p2 = np.array(p2)

    d_error_best = 10000000
    index_best = None
    for _ in range(loop_n):
        random.shuffle(index)
        index_pnp = index[:N_p3]
        index_test = index[N_p3:]
        p3_new = p3[index_pnp, :]
        p2_new = p2[index_pnp, :]
        R, rvecs, tvecs = calibration_RT(p3_new, p2_new, mtx, dist)

        p3_test = p3[index_test, :]
        p2_test = p2[index_test, :]
        d_error = 0
        print('\n\n')
        for i, p in enumerate(p3_test):
            coord = np.array([p[0], p[1], p[2]], dtype=np.float32)
            pre_xy = get_calibration_pixel(coord, rvecs, tvecs, mtx, dist)
            x, y = np.array(pre_xy).reshape(-1)

            d = np.sqrt(np.square(p2_test[i][0] - x) + np.square(p2_test[i][1] - y))
            d_error = d_error + d
            print("坐标索引:{}\t原始坐标--预测坐标:{}--{}\terror:{}".format(index_test[i], (p2[i][0], p2[i][1]), (x, y), d))
        d_error = d_error / (len(p3) - N_pnp)
        if d_error < d_error_best:
            d_error_best = d_error
            index_best = index[:N_p3]
            print("更新pnp最佳点index:", index_best)
            print("更新最佳距离误差:", d_error)
    print("pnp最佳点index:", index[:N_p3])
    print("最佳距离误差:", d_error_best)
    # 求解最佳对应外参值

    p3_new = p3[index_best, :]
    p2_new = p2[index_best, :]
    R, rvecs, tvecs = calibration_RT(p3_new, p2_new, mtx, dist)
    print("best rvecs=", rvecs)
    print("best tvecs=", tvecs)

    return index_best, rvecs, tvecs


if __name__ == '__main__':

    calibration = False
    predict_space = True  # 实际空间坐标标定
    predict_space_onepoint = False  # 测试空间中一点
    predict_board = False  # 决定测试标定版输出结果
    resize_img = False  # 将一个文件夹图片进行resize畸变矫正

    if calibration:
        img_root = r'C:\Users\vrc\Desktop\RadarCamera\data\123_0927\3'

        mtx_best, dist_best, total_error_best = None, None, 100000
        for i in range(60):
            mtx, dist, total_error = calibration_camera(img_root, rand_count=20)
            if total_error < total_error_best:
                total_error_best = total_error
                mtx_best = mtx
                dist_best = dist
                print("最小误差=", total_error_best)
        print("最优内参=", mtx_best)
        print("最优畸变系数=", dist_best)
        print("最小误差=", total_error_best)

    mtx = [[1.91272616e+03, 0.00000000e+00, 1.00189492e+03],
           [0.00000000e+00, 1.90272200e+03, 5.08191451e+02],
           [0.00000000e+00, 0.00000000e+00, 1.00000000e+00]]
    dist = [-4.47559224e-01, 3.19804795e-01, 3.29548350e-04, 1.01405096e-03,
            -1.99962118e-01]

    if predict_board:
        # 只针对标定板
        img_root = r'C:\Users\vrc\Desktop\RadarCamera\data\123_0927\2\5.jpg'
        img = revise_img(img_root, mtx, dist)
        img_root = './revise_img.jpg'
        _, _, rand_p3, rand_p2 = find_point_3d2d(img_root)

        # dist = [0, 0, 0, 0, 0]
        R, rvecs, T = calibration_RT(rand_p3, rand_p2, mtx, dist)

        # 通过内外参求解像素坐标
        # img_root = './revise_img.jpg'

        draw_board(img_root, mtx, R, T, dist=dist)
    if predict_space:
        img_root = r'C:\Users\vrc\Desktop\RadarCamera\data\data_0929\img_ori\13.jpg'

        # p3 = [[1000, 1000, 0], [-1000, 11000.0, 0], [-1000, 2000, 100], [1000, 2000, 0]]
        # p2 = [[861, 755.0], [320, 236], [178, 639], [787, 634]]
        p3 = [[2000, 2000, 0.0], [6000, 3000, 0], [3000, 5000, 0], [10000, 4000, 0]]
        p2 = [[1170, 555.0], [1252, 457], [1508, 525], [1303, 393]]

        R, rvecs, T = calibration_RT(p3, p2, mtx, dist)

        # coord = [[1, 3.0, 0, 1], [4, 5, 0, 1], [2, 6, 0, 1], [2, 2, 0, 1], [-1, 4, 0, 1]]

        coord = get_coord(X_range=[-6,40], Y_range=[-5,10], coord_size=1000)

        draw_space_new(img_root, coord, mtx, rvecs, T, dist)

    if predict_space_onepoint:
        p3 = [[1, 5.1, 0.77, 0],
              [2, 6.14, -0.26, 0],
              [3, 4.86, -0.9, 0],
              [4, 7.42, -1.28, 0],
              [5, 8.7, 0.51, 0],
              [6, 11.14, -1.41, 0],
              [7, 12.29, -0.26, 0],
              [8, 14.72, 1.79, 0],
              [9, 15.74, -7.4, 0],
              [10, 16.64, 1.79, 0],
              [12, 28.67, 3.33, 0],
              [13, 26.24, -2.05, 0],
              [15, 11.78, -2.05, 0],
              [16, 10.37, 3.2, 0],
              [17, 5.76, 2.56, 0],
              [18, 7.68, 0.51, 0]]
        p2 = [[1, 590, 359.0],
              [2, 1023, 309.0],
              [3, 1189, 352.0],
              [4, 1174, 274.0],
              [5, 778, 255.0],
              [6, 1143, 215],
              [7, 957, 204],
              [8, 670, 206],
              [9, 979, 186],
              [10, 710, 188],
              [12, 698, 147.0],
              [13, 1069, 141],
              [15, 1242, 211],
              [16, 1316, 259],
              [17, 156, 352],
              [18, 745, 283.0]]

        p3 = np.array(p3, dtype=np.float32)[:, 1:]
        p2 = np.array(p2, dtype=np.float32)[:, 1:]

        index=[0,3,8,12]
        p3_new,p2_new=p3[index],p2[index]
        R, rvecs, tvecs = calibration_RT(p3_new, p2_new, mtx, dist)
        # index, rvecs, tvecs = get_best_pnp_index(p3, p2, mtx, dist, N_pnp=6, loop_n=10000)

        # 计算剩余点坐标
        # img_root=r''
        for i, p in enumerate(p3):
            if i not in index:
                coord = np.array([p[0], p[1], p[2]], dtype=np.float32)
                pre_xy = get_calibration_pixel(coord, rvecs, tvecs, mtx, dist)
                x, y = np.array(pre_xy).reshape(-1)

                print("坐标索引:{}\t原始坐标--预测坐标:{}--{}".format(i, (p2[i][0], p2[i][1]), (x, y)))

    if resize_img:
        img_file = r'C:\Users\vrc\Desktop\RadarCamera\data\data_0928\img_ori'
        out_dir = build_dir(os.path.join(img_file, 'out_dir'))
        for img_name in os.listdir(img_file):
            if img_name[-3:] == 'jpg':
                img_root = os.path.join(img_file, img_name)
                img = revise_img(img_root, mtx, dist)
                cv2.imwrite(os.path.join(out_dir, img_name), img)

以上代码包含相机标定/原始图像外参求解

推荐标定误差分析博客:https://blog.csdn.net/weixin_48934707/article/details/124295140