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?

Answer 1

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 (3×8-bit pixels, true colour)
• RGBA (4×8-bit pixels, true colour with transparency mask)
• CMYK (4×8-bit pixels, colour separation)
• YCbCr (3×8-bit pixels, colour video format)
• I (32-bit signed integer pixels)
• F (32-bit floating point pixels)