mat2np.py

import scipy.io as sio
import numpy as np
import sys, os

def mat2np(path2mat, filename):

    matlab_file = sio.loadmat(path2mat)

    for k, v in matlab_file.items():
        if isinstance(v, np.ndarray):
            key = k
            break

    struct = matlab_file[key]
    mtx = struct['IntrinsicMatrix'][0][0]
    if not(np.all(mtx[2] != [0, 0, 1])) : mtx=mtx.T
    radial_dist = struct['RadialDistortion'][0][0].squeeze()
    tangential_dist = struct['TangentialDistortion'][0][0].squeeze()
    
    print("Intrinsic Parameters =\n", mtx,
        "\nRadial Distortion Parameter =\n", radial_dist,
        "\nTangential Distortion Parameters =\n", tangential_dist)
    
    if radial_dist.shape[0] == 2 : dist = np.append(radial_dist,tangential_dist)
    elif radial_dist.shape[0] == 3 : dist = np.append(np.append(radial_dist[0:2],tangential_dist),radial_dist[2])
    
    print('Calibration matrix =\n', mtx, '\nDistortion Coefficients (OpenCV style) :\n', dist)

    np.savez_compressed(filename, mtx=mtx, dist=dist)

if __name__ == "__main__":

    try: path2mat = sys.argv[1]
    except IndexError: path2mat = input('\nPlease enter the name of the .mat file that contains camera parameters:\n') 
    path2mat = os.path.join(os.getcwd(), path2mat)

    try: filename = sys.argv[2]
    except IndexError: filename = input('\nWhat should be the name of the numpy file to be save?\n') 
    filename = os.path.join(os.getcwd(), filename)

    mat2np(path2mat, filename)