Calibrate camera

camera_matrix.py

import numpy as np
import cv2 as cv
import glob

path_to_images = './dji-mini2/*.JPG'
draw_ui = False


def calibrate():
    # termination criteria
    criteria = (cv.TERM_CRITERIA_EPS + cv.TERM_CRITERIA_MAX_ITER, 30, 0.001)
    # prepare object points, like (0,0,0), (1,0,0), (2,0,0) ....,(6,5,0)
    gW = 9  # 7
    gH = 7  # 6
    objp = np.zeros((gH * gW, 3), np.float32)
    objp[:, :2] = np.mgrid[0:gW, 0:gH].T.reshape(-1, 2)
    objp = objp * 21

    # Arrays to store object points and image points from all the images.
    objpoints = []  # 3d point in real world space
    imgpoints = []  # 2d points in image plane.
    images = glob.glob(path_to_images)
    if draw_ui:
        # Create a Named Window
        cv.namedWindow('win_name', cv.WINDOW_NORMAL)

    for fname in images:
        print(fname)
        img = cv.imread(fname)
        gray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)
        # Find the chess board corners
        ret, corners = cv.findChessboardCorners(gray, (gW, gH), 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(corners2)
            if draw_ui:
                # Draw and display the corners
                cv.drawChessboardCorners(img, (gW, gH), corners2, ret)

                # Show the Image in the Window
                cv.imshow('win_name', img)

                # Resize the Window
                cv.resizeWindow('win_name', 1920, 1080)

                cv.waitKey(500)

    (h, w) = gray.shape
    ret, mtx, dist, rvecs, tvecs = cv.calibrateCamera(objpoints, imgpoints, (w, h), None, None)
    print(mtx)
    if draw_ui:
        cv.destroyAllWindows()
    return mtx

calibrate()