On 11/16/2012 12:40, Unaiza Ahsan wrote:
> Hi all,
>
> I am following Jan Erik Solem's book "Programming Computer Vision with
> Python" and I'm just on the first chapter. The book asked us to create a
> file imtools.py and put down helpful functions there, which we can just
> call later.
>
> There is a function created for histogram equalization of images (called *
> histeq*), and saved in imtools.py. When I use this function and type this
> in IDLE:
>>>> from PIL import Image
>>>> from numpy import *
>>>> im = array(Image.open('Tulips.jpg').convert('L'))
>>>> im2,cdf = imtools.histeq(im)
>
> I get this:
>
> Traceback (most recent call last):
> File "<pyshell#59>", line 1, in <module>
> im2,cdf = imtools.histeq(im)
> File "C:\Python27\imtools.py", line 18, in histeq
> imhist,bins = histogram(im.flatten(),nbr_bins,normed=True)
> NameError: global name 'histogram' is not defined
>
> And the relevant portion in imtools.py is:
> def histeq(im,nbr_bins=256):
> """ Histogram equalization of a grayscale image. """
>
> #get image histogram
> imhist,bins = histogram(im.flatten(),nbr_bins,normed=True)
> cdf = imhist.cumsum() #Cumulative distribution function
> cdf = 255* cdf/cdf[-1] #Normalize
>
> #Use linear interpolation of cdf to find new pixel values
> im2 = interp(im.flatten(), bins[:-1],cdf)
>
> return im2.reshape(im.shape), cdf
>
> ------------------------------------
> Can anybody point out where I'm going wrong? I have Python 2.7, NumPY,
> SciPY etc.
>
> Thanks very much
>
> Python Newbie!
Where is the histogram() function from? Is it in imtools.py as well?
--
staticsafe
O< ascii ribbon campaign - stop html mail - www.asciiribbon.org
Please don't top post - http://goo.gl/YrmAb
_______________________________________________
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor
