Displaying a grayscale Image

Question

My aim:

1. Read an image into the PIL format.
2. Convert it to grayscale.
3. Plot the image using pylab.

Here is the code i'm using:

from PIL import Image
from pylab import *
import numpy as np

inputImage='C:\Test\Test1.jpg'
##outputImage='C:\Test\Output\Test1.jpg'

pilImage=Image.open(inputImage)
pilImage.draft('L',(500,500))
imageArray= np.asarray(pilImage)

imshow(imageArray)

##pilImage.save(outputImage)

axis('off')

show()

My Problem: The image get's displayed like the colours are inverted.

But I know that the image is getting converted to grayscale, because when I write it to the disk it is appearing as a grayscale image.(Just as I expect).

I feel that the problem is somewhere in the numpy conversion.

I've just started programming in Python for Image Processing. And Tips and Guideline will also be appreciated.

Answer 1

You want to over-ride the default color map:

imshow(imageArray, cmap="Greys_r")

Here's a page on plotting images and pseudocolor in matplotlib .