Computer Graphics with Photoshop - How to geometrically transform objects using control points?

Author

How to geometrically transform objects using control points?

Carlos N

2006-09-02, 3:16 am

I have a seemingly simple problem, but I can't find an easy way to do it.

I have photographs of two objects which should look identical. However,
they were taken from slightly different angles - close enough that they can
be transformed to look the same.

I want to transform one object to have the same exact shape (i.e.
perspective) as the other. I have been able to this roughly by using a
"free transform" of a selection, and stretching individual corners so that
the objects come close to matching up.

What I'd much rather do, is select points 1,2,3,4 on both images and then
tell Photoshop, transform picture 2 so that the four control points are in
the same exact location as those of picture 1.

Is it possible to do this? Is there a plugin that can help?

Note - in the future, I have another project that would necessitate even
more control points to transform (matching up 2 maps), so a generic
solution is better, if possible.

Thanks!
Carlos

Carlos N

2006-09-02, 3:16 am

One potential way of doing what I want would be to use the "warp" transform
... if it had more points for warping than just the corner bezier guides.

Carlos

Carlos N wrote:
> I have a seemingly simple problem, but I can't find an easy way to do it.
>
> I have photographs of two objects which should look identical. However,
> they were taken from slightly different angles - close enough that they
> can be transformed to look the same.
>
> I want to transform one object to have the same exact shape (i.e.
> perspective) as the other. I have been able to this roughly by using a
> "free transform" of a selection, and stretching individual corners so
> that the objects come close to matching up.
>
> What I'd much rather do, is select points 1,2,3,4 on both images and
> then tell Photoshop, transform picture 2 so that the four control points
> are in the same exact location as those of picture 1.
>
> Is it possible to do this? Is there a plugin that can help?
>
> Note - in the future, I have another project that would necessitate even
> more control points to transform (matching up 2 maps), so a generic
> solution is better, if possible.
>
> Thanks!
> Carlos

Ethergnat

2006-09-02, 3:16 am

I don't know of anything made for matching the perspective of two
photos, but there are plugins that allow for easy correction of barrel
distortion and perspective correction. I would think if you ran such a
plugin on both images they would match up pretty well.

I've used Andromeda's LensDoc. It's very easy to use, powerful, and
unfortunately quite pricey at $98.
http://www.andromeda.com/main/lensdoc.php

There are more affordable options--just google something like barrel
distortion photoshop plugin.

FredEx

2006-09-02, 3:16 am

On Fri, 01 Sep 2006 23:13:16 -0400, Carlos N
<spaceman13DELETE@REMOVEbestmail.us> wrote:

>One potential way of doing what I want would be to use the "warp" transform
> ... if it had more points for warping than just the corner bezier guides.
>
>Carlos

Just off the top of my head...might a morphing program work?

--
FredEx

John@world.com

2006-09-02, 6:16 am

On Fri, 01 Sep 2006 22:50:36 -0400, Carlos N
<spaceman13DELETE@REMOVEbestmail.us> wrote:

>I have a seemingly simple problem, but I can't find an easy way to do it.
>
>I have photographs of two objects which should look identical. However,
>they were taken from slightly different angles - close enough that they can
>be transformed to look the same.
>
>I want to transform one object to have the same exact shape (i.e.
>perspective) as the other. I have been able to this roughly by using a
>"free transform" of a selection, and stretching individual corners so that
>the objects come close to matching up.
>
>What I'd much rather do, is select points 1,2,3,4 on both images and then
>tell Photoshop, transform picture 2 so that the four control points are in
>the same exact location as those of picture 1.
>
>Is it possible to do this? Is there a plugin that can help?
>
>Note - in the future, I have another project that would necessitate even
>more control points to transform (matching up 2 maps), so a generic
>solution is better, if possible.
>
>Thanks!
>Carlos

Have a look at

http://www.dpreview.com/learn/?/Ima...rrection_01.htm

Kingdom

2006-09-02, 6:16 pm

Carlos N <spaceman13DELETE@REMOVEbestmail.us> wrote in
news:edarht$n2i$1@netnews.upenn.edu:

> I have a seemingly simple problem, but I can't find an easy way to do
> it.
>
> I have photographs of two objects which should look identical.
> However, they were taken from slightly different angles - close enough
> that they can be transformed to look the same.
>
> I want to transform one object to have the same exact shape (i.e.
> perspective) as the other. I have been able to this roughly by using
> a "free transform" of a selection, and stretching individual corners
> so that the objects come close to matching up.
>
> What I'd much rather do, is select points 1,2,3,4 on both images and
> then tell Photoshop, transform picture 2 so that the four control
> points are in the same exact location as those of picture 1.
>
> Is it possible to do this? Is there a plugin that can help?
>
> Note - in the future, I have another project that would necessitate
> even more control points to transform (matching up 2 maps), so a
> generic solution is better, if possible.
>
> Thanks!
> Carlos
>

Doubt you can do it in photoshop but try looking for free or trial
morphing software that might do it for you.

--
------------------------------------------------------------------------
Learning is not attained by chance, it must be sought for with ardor and
attended to with diligence.
------------------------------------------------------------------------

Tom Nelson

2006-09-03, 6:16 pm

Try Automate>Photomerge. Usually, you shoot several pictures with an
area of overlap and Photoshop warps the photos to best put the
overlapping parts on top of each other.

In this case, you have two photos with image overlap which completely
covers the frame. This should make it even easier. Click the "Keep As
Layers" button. Make each layer its own picture and you're done.

Tom Nelson
Tom Nelson Photography

In article <edarht$n2i$1@netnews.upenn.edu>, Carlos N
<spaceman13DELETE@REMOVEbestmail.us> wrote:

> I have a seemingly simple problem, but I can't find an easy way to do it.
>
> I have photographs of two objects which should look identical. However,
> they were taken from slightly different angles - close enough that they can
> be transformed to look the same.
>
> I want to transform one object to have the same exact shape (i.e.
> perspective) as the other. I have been able to this roughly by using a
> "free transform" of a selection, and stretching individual corners so that
> the objects come close to matching up.
>
> What I'd much rather do, is select points 1,2,3,4 on both images and then
> tell Photoshop, transform picture 2 so that the four control points are in
> the same exact location as those of picture 1.
>
> Is it possible to do this? Is there a plugin that can help?
>
> Note - in the future, I have another project that would necessitate even
> more control points to transform (matching up 2 maps), so a generic
> solution is better, if possible.
>
> Thanks!
> Carlos