How can I convert a colorful pfm image to a png one?

Question

So I found a code on Github that can convert pfm grayscales images to png ones. The problem with this code is that it's not working on colourful images.

Here is an image sample that I wanna convert to a png extension : https://drive.google.com/file/d/16yP987otoCyOX-ail22Aru2AltnSa1hR/view?usp=sharing It's a link cause I can't upload pfm images :)

The link to the original code : https://github.com/MahdiGhiasi/DepthEstimationProject/blob/master/pfm2png/pfm2png_depth.py

from PIL import Image
import numpy as np
import colorsys
import sys
import re
import os

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

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

    header = file.readline().rstrip().decode('utf-8')
    if header == 'PF':
        color = True
    elif header == 'Pf':
        color = False
    else:
        print(header)
        raise Exception('Not a PFM file.')

    dim_match = re.match(r'^(\d+)\s(\d+)\s$', file.readline().decode('utf-8'))
    if dim_match:
        width, height = map(int, dim_match.groups())
    else:
        raise Exception('Malformed PFM header.')

    scale = float(file.readline().rstrip().decode('utf-8'))
    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, color

def writePFM(file, image, scale=1):
    
    file = open(file, 'wb')

    color = None

    if image.dtype.name != 'float32':
        raise Exception('Image dtype must be float32.')
      
    image = np.flipud(image)  

    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)

    image.tofile(file)

def save_depth_image(result, image_path):
    
    height = len(result)
    width = len(result[0])

    maxVal = np.max(result)

    #print("width:", width)
    #print("height:", height)

    output = []
    for i in range(height):
        row = []
        for j in range(width):
            h = 240 * result[i][j] / maxVal;
            (r,g,b) = colorsys.hsv_to_rgb(h / 360,1,1)
            #color = (int)(255 * result[j][i] / maxVal)
            row.append([int(r * 255), int(g * 255), int(b * 255), 255])
        output.append(row)

    img = Image.fromarray(np.asarray(output).astype(np.uint8), mode='RGBA')
    
    img.save(image_path, "PNG")

def normalize(data):
    
    maxVal = np.max(data)

    print("maxVal:", maxVal)

    data = data / maxVal
    data = 1 - data
    data *= 90

    return data

file_name = input("pfm file?\n")

data, scale, color = readPFM(file_name)

data = normalize(data)

if color:
    print("Not a depth file")
else:
    save_depth_image(data, 'pfm2png_depth.png')
    os.startfile('pfm2png_depth.png')

Answer 1

no need to roll code for this:

import cv2
img = cv2.imread("img.pfn", cv2.IMREAD_UNCHANGED) # it's float32 !
img /= 255 # back to [0..255]
cv2.imwrite("img.png", img)