Photo Processing - Brightness and Unsharp Mask

[Wilhelm Sanke]

On Mon, 29 May 2006 , Sivakatirswami <katir at hindu.org> wrote:

> >>The filter matrix can  
> >> be used to experiment with own matrix settings.
>
> hmmm 3 X 3? ... too small. Does  it mean that any starting image must  
> have this rect?


3X3, of course, means the size of the matrix filter, you can use Chipp's 
DLL for any image size and different rects (as far as my experiments 
went). My own scripted filters are adapted to an image size of 640X480, 
but that could be easily changed; however, the larger the image, the 
more processing time is needed - execution time for most of the no-dll 
640X480 filters is between 1 and 2 seconds. When the DLLs are used, the 
results are instantaneous.

As I have already mentioned as a request,  a nice add-on for Revolution 
would be a DLL (and the equivalent for MacOS) for a filter size of 5X5 
or even better 7X7. Photoshop CS (1) allows for the setting-up of 
user-defined filters with a 5X5 matrix. PaintShop Pro offers a 7X7 matrix.

I am not familiar with creating DLLs, but my guess is that it could not 
be too difficult to extend the functionality of Chipp's and Derek Bump's 
3X3-matrix DLL to cover a 7X7 filter matrix.

One thing is missing in the 3X3 Dlls, which include the "division" 
factor - "scale" in Chipp's and Derek's stacks,  namely what is called 
"shift" in Photoshop and "bias" in PaintShop Pro. This is a color value 
to be added to the equation important for instance for creating "relief" 
(and other) effects. I tried to add such a "bias" to Chipp's scripted 
(without DLL) solution, but did not get the same results as with 
PaintShop Pro. Otherwise the PaintShopPro sample filters, so far as they 
fit into a 3X3 matrix, yield the same results in my "ImageFilterDemo" 
that contains a modified version of Chipp's stack.

Especially PaintShop Pro 8 contains about 15 3X3 usable matrix filters, 
versions 7 and 10 only about 5, that could be used in our sample stacks. 
I will add some of these filters to a new release of my ImageFilterDemo.
I might also give it a try - in case I find time - to extend Chipp's 
no-dll version to encompass a 4X4 matrix.

> >> I am experimenting myself with scripted filters, some of which are  
> >> contained in the ImageFilterDemo, about a hundred or so will be  
> >> available shortly in my "Imagedata Toolkit".
>
> Keep us all posted.  My needs are pretty much always the same -- and  
> this would apply to most users needing to get from raw camera to web  
> quickly, assuming they don't have time to  tweak levels or fix red-
> eye -- or  those who have no clue what that stuff even means.
>
> one  pass: raw Digital camera image.jpg
> 1) rotate
> 2) downsize
> 3) autolevels
> 4) unsharp mask (I will try sharpening, but for sure it's not as good  
> for edges)
> 5) save jpg "optimize"
>
> Option to turn off 4) 5) above where the image has already been  
> through one in interpolation and more  filters will simply degrade.
>
> Sivakatirswami


The needs are certainly different for all users, but in any case it 
would be a valuable enhancement to Revolution to have improved 
image-processing capabilities, both with extended filter matrices and 
possibly with a DLL that would open the door to work with 
Photoshop-compatible plugin-filters.

Such enhancements would certainly attract new users and encourage 
present Revolution users to experiment with image processing.

Regards,

Wilhelm Sanke
<http://www.sanke.org/MetaMedia>