How to convert a PIL Image into a numpy array

Question

I'm trying around with converting a PIL image object back and forth to a numpy array so I can do some faster pixel by pixel transformations than PIL's PixelAccess object would allow. I've figured out how to place the pixel information in a useful 3D numpy array by way of:

pic = Image.open("foo.jpg")
pix = numpy.array(pic.getdata()).reshape(pic.size[0], pic.size[1], 3)

But I can't seem to figure out how to load it back into the PIL object after I've done all my awesome transforms. I'm aware of the putdata() method, but can't quite seem to get it to behave.

Answer 1

Hello @kartik,

You just need to convert your image to a numpy array this way:

import numpy
import PIL

img = PIL.Image.open("foo.jpg").convert("L")
imgarr = numpy.array(img) 

Thank You!!