IO.py

import re

import numpy as np


def readPFM(file):
    file = open(file, 'rb')

    color = None
    width = None
    height = None
    scale = None
    endian = None

    header = file.readline().rstrip()
    if header.decode("ascii") == 'PF':
        color = True
    elif header.decode("ascii") == 'Pf':
        color = False
    else:
        raise Exception('Not a PFM file.')

    dim_match = re.match(r'^(\d+)\s(\d+)\s$', file.readline().decode("ascii"))
    if dim_match:
        width, height = list(map(int, dim_match.groups()))
    else:
        raise Exception('Malformed PFM header.')

    scale = float(file.readline().decode("ascii").rstrip())
    if scale < 0:  # little-endian
        endian = '<'
        scale = -scale
    else:
        endian = '>'  # big-endian

    data = np.fromfile(file, endian + 'f')
    shape = (height, width, 3) if color else (height, width)

    data = np.reshape(data, shape)
    data = np.flipud(data)
    return data, scale


def readFlow(name):
    if name.endswith('.pfm') or name.endswith('.PFM'):
        return readPFM(name)[0][:, :, 0:2]

    f = open(name, 'rb')

    header = f.read(4)
    if header.decode("utf-8") != 'PIEH':
        raise Exception('Flow file header does not contain PIEH')

    width = np.fromfile(f, np.int32, 1).squeeze()
    height = np.fromfile(f, np.int32, 1).squeeze()

    flow = np.fromfile(f, np.float32, width * height * 2).reshape((height, width, 2))

    return flow.astype(np.float32)