Alien Anomalies

Members Login
Post Info TOPIC: More on stretching the greyscale of an image


Teaching the truth

Status: Offline
Posts: 1891
Date:
RE: More on stretching the greyscale of an image
Permalink  
 


Please dont ask me where I found this image 'cos I have forgotten and wish I could remember. It is awesome. Probably the best statue-head we have so far.

The second image is split into 24 which looks quite good after blurring. Obviously not so good if you need to look at close detail.

222section500.jpg

222section500_gaussian_4x6.jpg

222section500_gaussian.jpg



Attachments
__________________


 



Teaching the truth

Status: Offline
Posts: 1891
Date:
Permalink  
 

In order to make features more obvious we need to "process" the image to lighten,darken,add contrast etc. However, the way I have been trying to develop over the years is to

1) lighten the shadows to see whats in there

2) make the features stand out more by stretching the image to use the full range of greys (0-255)

I have been doing this stuff on the whole image and often if the image has already been 'processed' by Nasty, then there are no more greys to be extracted from the image 'cos they have already done it. That means the lowest value of grey in the image is 0 (black) and the highest is 255(white).

Now I cannot think why this did not occur to me before but if I split the image up into pieces and stretch each piece then there ARE more grey values which can be teased out of the image. Now, if I put the image back together again after I have stretched each piece, it does look a little strange, but the space between greys is expanded which makes the features stand out more.

As an example see below original on left, chopped and stretched on the right.

2017-07-24-201213_906x761_scrot_650.png

As you can see (apart from making it black and white, and not colour any more) the overall effect is to make the whites lighter and the greys darker making the contrast better.
If you want me to have a go at a particular image then send me a message with the link and I will try to do my magic on it.

 



Attachments
__________________


 

Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.

Tweet this page Post to Digg Post to Del.icio.us


Create your own FREE Forum
Report Abuse
Powered by ActiveBoard