#!/usr/bin/env python
# -*- coding: UTF-8 -*-
'''
读写pfm格式的图片文件
'''
import os
import re
import sys
import numpy as np
def load_pfm(fname):
assert os.path.isfile(fname)
color = None
width = None
height = None
scale = None
endian = None
file = open(fname)
header = file.readline().rstrip()
if header == 'PF':
color = True
elif header == 'Pf':
color = False
else:
raise Exception('Not a PFM file.')
dim_match = re.match(r'^(\d+)\s(\d+)\s$', file.readline())
if dim_match:
width, height = map(int, dim_match.groups())
else:
raise Exception('Malformed PFM header.')
scale = float(file.readline().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)
return np.flipud(np.reshape(data, shape)).copy(), scale
def save_pfm(fname, image, scale=1):
file = open(fname, 'w')
color = None
if image.dtype.name != 'float32':
raise Exception('Image dtype must be float32.')
if len(image.shape) == 3 and image.shape[2] == 3: # color image
color = True
elif len(image.shape) == 2 or len(image.shape) == 3 and image.shape[2] == 1: # greyscale
color = False
else:
raise Exception('Image must have H x W x 3, H x W x 1 or H x W dimensions.')
file.write('PF\n' if color else 'Pf\n')
file.write('%d %d\n' % (image.shape[1], image.shape[0]))
endian = image.dtype.byteorder
if endian == '<' or endian == '=' and sys.byteorder == 'little':
scale = -scale
file.write('%f\n' % scale)
np.flipud(image).tofile(file)
