Ideally, there should be a tool in J to align images.
(In fact it's quite simple.)
But to experiment, I recommend a good photo editor,
PhotoShop :-) is easy, but Gimp should do it too:
- put the two pictures in two layers of one image
- set the top layer transparency to see through
- choose "Move Tool", which allows to shift and rotate the layer
- save the layers separately into new picture files
It's better to work with either a subset or
a scaled down version of the images, 1024x1024 or so,
while you work out the technique.
There is a good intro into image cleanup filters
by Cliff Reiter in APL Quote Quad.
See also his web site for the scritps.
Note: some amount of noise and intesity variations
are controled by the level of threshhold.
--- Björn Helgason <[EMAIL PROTECTED]> wrote:
> I have been making some manual work in aligning the pictures
> Take easily recognizable parts of the picture to compare
> I have noticed that I have to move one picture a bit to the right and up
> which is relatively easy looking at the results with viewrgb and picking
> different indexes to move them along
> It is good fun to play with pictures this way
>
> There is quite a bit of noise on the pictures
>
> To get the patterns aligned may also need a bit of turnings as well which is
> a bit harder to do
>
> I wonder if there are any tools to do such pattern matching automatically
>
> Also something to smooth out noise and make the patterns stand out better
>
>
> 2006/11/2, Oleg Kobchenko <[EMAIL PROTECTED]>:
> >
> > There may be different techniques depending on
> > the goals of the comparison and conditions of
> > input images, such as
> > - alignment and "exposure" transformations to match two images
> > - processing for easy visual identification of diffs
> >
> > E.g. for visual identification, that will show one
> > of the images with differences area highlighted
> > - make sure images align (can be manual visual tool)
> > - get difference
> > - get 0,1 bitmap as threshhold of the difference image
> > - apply some visible filter using the bitmap mask,
> > such as elevate R and suppress G,B
> > f(r,g,b) = (r+m*d),(g-m*d),(b-m*d); m={0,1}, d=10 or so
> >
> > For automated qualitative analysis, there is
> > a good summary of image operations
> > http://homepages.inf.ed.ac.uk/rbf/HIPR2/
> >
> > platimg returns image in hex 0xRRGGBB form, and
> > most of the operations work on each color component
> > separately.
> >
> >
> > --- Björn Helgason <[EMAIL PROTECTED]> wrote:
> >
> > > I downloaded platimg from
> > >
> > > http://olegykj.sourceforge.net/
> > >
> > > I ran the test script and could take in my jpg picture and display part
> > of
> > > it on the form
> > > (excellent tools on this page!!)
> > >
> > > I am pretty new to this picture scene and I wonder if there are tools
> > > available to scale the jpg images as well as compare differences between
> > jpg
> > > pictures
> > > Like I have 15 pictures taken of the same object but there are
> > supposedly
> > > small differences between them that I do not know about
> > > Each is 6MB in size
> > >
> > > Getting the picture displayed is a major step for me but I have not got
> > a
> > > clue as to how to compare them in J and what to do next
> > >
> > > --
> > > Björn Helgason, Verkfræðingur
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