[Award Winner] Bitmapped Images - The technical side of things explained.

[Redrobes]

I think that gamma correction does nothing to the image data itself, it is simply a setting for when image is displayed on monitor.

You can apply color correction and gamma adjustment globally at the video card stage and this would affect everything and not affect the pixel values but to do that color fix up with resampling, you have to apply a gamma function to the pixels first and then apply the stretch and then apply the inverse gamma function. Although in the example provided the first gamma function does nothing because all of the colors start saturated if you tried to do it to a photo then you need that first gamma adjustment if your going to apply an inverse one later. Your right in that gamma adjustments are used to compensate for the effects of monitors - esp CRT type. Why this process works to fix this problem I am not sure. I am not sure if a different compensation curve would also work.

[mathuwm]

http://www.ononesoftware.com/product...e_fractals.php

This is a link to program that does an incredible job at up scaling images

I can not tell you how much I wish I had this program at my current job

I am sick of getting 15 kb .jpg logo files

[Redrobes]

Would you like to take the middle image from post #11, take the top left small bit and scale it up very high (800%) and cut out the bit of petal like the others so we can compare ?

[RobA]

Here is another freeware application that provides a few other enlarging modes:
http://logicnet.dk/Analyzer/

Here are some results:

Wiener 4:
weiner4_resize.png

Wiener 6:
weiner6_resize.png

Sinc:
sinc_resize.png

XinLi:
xinLifractal_resize.png

Fractal 5 - XinLi:
fractal5xinli_resize.png

-Rob A>

[Redrobes]

Thats brilliant Rob. Are you able to edit the post and label them as to what they mean. I have to say I do not think that they are an improvement over ordinary methods tho. The one Mathuwm suggested is critically acclaimed and supposed to be very good indeed so I am curious. It appears I have repped you enough already

[mathuwm]

resampled with Genuine fractals

[Redrobes]

I am expecting great things from this super resampler but I cant accept this. This is too good. Is this the small image in the top left of the middle image of post 11 - I have attached it again below. How can it reproduce perfect stamen from a single pixel... tell me this was from a different image !

Can you do the image attached at 800% or x8 mag ?


Edit -- I can see that this must have come from top left of post #2 and not post #11. Its still very good but it would be great to have a side by side comparison from the same source.

[mathuwm]

the 120x96 pixal image

No i do not think that would work to well.

the larger the image the better it upscales

this program is used a lot for upscaling images for printing on a large format printer

what i did was take this:
Image size-1.png

and scale it to this

I actually cropped it after I scaled it so the actual differences might be slightly off

Image size-2.png

[RobA]

A few more with that freebee Image Analyzer I referred to (quite the swiss army knife, really!), using the sample image, enlarged 800%

Wiener 4:
wiener 4.png

Two of the fractals (no idea what the parameters do just playing). I got the best results by going x2, x2, x2 rather than straight (the image names include the parameters):
resize_Temp x2 region=7 regul=0 x2 region=7 regul=0 x2 region=7 regul=0.png
resize_Temp x2 region=9 regul=0 x2 region=9 regul=0 x2 region=9 regul=0.png

And two more from Gimp - progressive resize, 800% in 20 steps:
gimp_resize_steps.png

and a gimp plugin "smart enlarge" using resyntherizer(?) I enlarged 2x 2x 2x. The first was OK, but after that it certainly added detail, but bolloxed up the image:
gimp_resynth_1.png

-Rob A>