from pathlib import Path
import numpy as np
import struct
def read_pfm(filename):
with Path(filename).open('rb') as pfm_file:
line1, line2, line3 = (pfm_file.readline().decode('latin-1').strip() for _ in range(3))
assert line1 in ('PF', 'Pf')
channels = 3 if "PF" in line1 else 1
width, height = (int(s) for s in line2.split())
scale_endianess = float(line3)
bigendian = scale_endianess > 0
scale = abs(scale_endianess)
buffer = pfm_file.read()
samples = width * height * channels
assert len(buffer) == samples * 4
fmt = f'{"<>"[bigendian]}{samples}f'
decoded = struct.unpack(fmt, buffer)
shape = (height, width, 3) if channels == 3 else (height, width)
return np.flipud(np.reshape(decoded, shape)) * scale
import matplotlib.pyplot as plt
image = read_pfm('memorial.pfm')
plt.imshow(image)
plt.show()
我对Python完全不熟悉,但是这里有一些关于阅读PFM
(便携式浮点映射)文件的建议。
选项 1
ImageIO 文档 这里建议您可以下载并使用 FreeImage 阅读器。
选项2
我自己拼凑了一个简单的阅读器,似乎在我找到的一些示例图像上以及用ImageMagick生成的图像上都可以正常工作。它可能包含低效或不良实践,因为我不会说Python。
#!/usr/local/bin/python3
import sys
import re
from struct import *
# Enable/disable debug output
debug = True
with open("image.pfm","rb") as f:
# Line 1: PF=>RGB (3 channels), Pf=>Greyscale (1 channel)
type=f.readline().decode('latin-1')
if "PF" in type:
channels=3
elif "Pf" in type:
channels=1
else:
print("ERROR: Not a valid PFM file",file=sys.stderr)
sys.exit(1)
if(debug):
print("DEBUG: channels={0}".format(channels))
# Line 2: width height
line=f.readline().decode('latin-1')
width,height=re.findall('\d+',line)
width=int(width)
height=int(height)
if(debug):
print("DEBUG: width={0}, height={1}".format(width,height))
# Line 3: +ve number means big endian, negative means little endian
line=f.readline().decode('latin-1')
BigEndian=True
if "-" in line:
BigEndian=False
if(debug):
print("DEBUG: BigEndian={0}".format(BigEndian))
# Slurp all binary data
samples = width*height*channels;
buffer = f.read(samples*4)
# Unpack floats with appropriate endianness
if BigEndian:
fmt=">"
else:
fmt="<"
fmt= fmt + str(samples) + "f"
img = unpack(fmt,buffer)
选项 3
如果您无法在 Python 中读取您的 PFM
文件,您可以使用命令行中的 ImageMagick 将它们转换为另一种格式(例如 TIFF),该格式可以存储浮点样本。 ImageMagick 已安装在大多数 Linux 发行版上,并可用于 macOS 和 Windows:
magick input.pfm output.tif
img = imageio.imread('image.pfm')
就这样做吧。为了方便使用,它可以转换为numpy数组。
img = numpy.asarray(img)