how to convert raw images to png in python?

Question

I have a folder containing over 200 raw images, i want to convert all of them to png or any other format, In C it's pretty easy but in python i don't know how it's done

I found this snippet

#import struct
import numpy, array, PIL, Image
from struct import *

#declarations
arr1D   =   array.array('H') #H is unsigned short

#------------------------------------
#read 16 bit unsigned raw depth image
#------------------------------------
w           =   640
h           =   480
fid        =   open('/home/salman/salman/NiSimpleRead_salman/data/200.raw')
#fid         =   open('/home/salman/test.raw')
numBytes    =   w*h
arr1D.read(fid, numBytes)
fid.close()

#----------------------------------------------------
#convert to float numpy array -> scale -> uint8 array
#----------------------------------------------------
numarr = numpy.array(arr1D, dtype='float');
numarr = 255 - (numarr*255.0/numarr.max())
numarr.shape = (h,w)
numarr = numarr.astype('uint8')

#======================
#IMAGES
#======================

#2D numpy array -> image 
#-----------------------
img        =   Image.fromarray(numarr); #print data.dtype.name

#image view and save
#-------------------
#img.show()
img.save('/home/salman/test.png')

This is the only snippet that I can find, is this the proper way to do it?

Alternately, use ImageMagick at the command line: `convert *.raw --format png`. — Li-aung Yip, Mar 29 '12 at 11:25
Or, alternately alternately, use the ImageMagick bindings for Python. — Li-aung Yip, Mar 29 '12 at 11:26
@jsbueno, What I meant by saying *"In C it is pretty easy"* is that i saw so many snippets converting `raw` to other formats but i only saw 1 snippet in python — user, Mar 29 '12 at 21:13

score 10 · Accepted Answer · edited May 23 '17 at 12:23

10

It should be something like:

rawData = open("foo.raw" 'rb').read()
imgSize = (x,y)
# Use the PIL raw decoder to read the data.
# the 'F;16' informs the raw decoder that we are reading 
# a little endian, unsigned integer 16 bit data.
img = Image.fromstring('L', imgSize, rawData, 'raw', 'F;16')
img.save("foo.png")

Using the handbook and another SO question.

The First argument is the image mode and can be any from:

1 (1-bit pixels, black and white, stored with one pixel per byte)
L (8-bit pixels, black and white)
P (8-bit pixels, mapped to any other mode using a colour palette)
RGB (3x8-bit pixels, true colour)
RGBA (4x8-bit pixels, true colour with transparency mask)
CMYK (4x8-bit pixels, colour separation)
YCbCr (3x8-bit pixels, colour video format)
I (32-bit signed integer pixels)
F (32-bit floating point pixels)

edited May 23 '17 at 12:23

Community

1
1

answered Mar 29 '12 at 09:22

brice

24,329
7
79
95

`F;16` is no longer true as an unsigned integer. I think they are now using it as float. If I'm not mistaken. – majidarif Oct 06 '18 at 00:46
This answer is no longer accurate. Refer: https://stackoverflow.com/a/45445890/8055011 – Harshit Jindal Mar 07 '20 at 12:32
How to do reverse of this? I have ndarray and I want to write (.raw) format image ? – Uday Posia Aug 17 '20 at 05:21

score 9 · Answer 2 · answered Aug 01 '17 at 19:10

9

from PIL import Image
rawData = open("foo.raw", 'rb').read()
imgSize = (703,1248)# the image size
img = Image.frombytes('L', imgSize, rawData)
img.save("foo.jpg")# can give any format you like .png

was the one that worked for me

answered Aug 01 '17 at 19:10

Anupiya Nugaliyadde

91
1
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How to do reverse of this? I have ndarray and I want to write (.raw) format image ? – Uday Posia Aug 17 '20 at 05:22

how to convert raw images to png in python?

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