# [Numpy-discussion] eigenface image too dark

Nadav Horesh nadavh@visionsense....
Wed Mar 19 04:51:44 CDT 2008

```Easy solution:
Use pylab's imashow(inputarray).
In general ipython+matplolib are very handy for your kind of analysis

Longer solution:
Scale your array:
a_min = inputarray.min()
a_max = inputarray.max()
disp_array = ((inputarray-a_min)* 255/(a_max - a_min)).astype('uint8')\
.
.
.
newimg.putdata(disp_array)

Nadav.

-----הודעה מקורית-----
מאת: numpy-discussion-bounces@scipy.org בשם royG
נשלח: ד 19-מרץ-08 08:23
אל: numpy-discussion@scipy.org
נושא: [Numpy-discussion] eigenface image too dark

hi
while trying to make an eigenface image from a numpy array of floats i
tried this

from numpy import array
import Image

imagesize=(200,200)
def makeimage(inputarray,imagename):
inputarray.shape=(-1,)
newimg=Image.new('L', imagesize)
newimg.putdata(inputarray)
newimg.save(imagename)

since i am using images of 200X200 size,
i use an array with 40000 elements  like
[ -92.35294118  -81.88235294  -67.58823529 ...,   -3.47058824
-13.23529412   -9.76470588]
the problem is ,i get an image that is too dark.it looks like a face
but is too dark that even different arrays will create images that all
look alike!..
s there a way to 'tone it down' so that i can generate an eigenface
that can be displayed better?

thanks
RG
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