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Three point layer distortion mapping feature?

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Three point layer distortion mapping feature? Mark Lowry 02 May 22:53
  Three point layer distortion mapping feature? Chris Mohler 03 May 00:46
   Three point layer distortion mapping feature? Mark Lowry 03 May 03:19
    Three point layer distortion mapping feature? GSR - FR 03 May 04:21
  Three point layer distortion mapping feature? Tom Lechner 03 May 05:29
  Three point layer distortion mapping feature? David Hodson 03 May 10:58
Mark Lowry
2007-05-02 22:53:42 UTC (over 17 years ago)

Three point layer distortion mapping feature?

A plug-in that takes three control points on a layer and then distorts the layer (by scaling, translating, rotating, and stretching) so that those points end up on three other identified control points would be very useful. For example, if you wanted to combine two images shot at different exposures to increase the dynamic range and the shots were handheld, you would need to do some or all of these manipulations in order to make the images line up as well as possible. The first three portions of this function, scaling, translating, and rotating, can all be done with existing GIMP plug-ins, and I have written a script-fu to do just that. But the stretching function that is required to help account for variations in lens distortion due to slightly different image centers (from hand-holding) is not possible.

Such a plug-in would ideally work with a minimum of two points (in which case the stretching is not performed) and could theoretically work with more than three points to allow for even better control of the mapping. Having live feedback of the manipulation, either through a preview window or on the image window), would greatly assist the user with determining how many points are required to adequately perform the manipulation. Having the ability to place the control points and then tweak their position by dragging them while observing the live feedback would be ideal.

What are everyone's thoughts on this? Is it worth initiating an enhancement request in Bugzilla?

___

Chris Mohler
2007-05-03 00:46:27 UTC (over 17 years ago)

Three point layer distortion mapping feature?

On 5/2/07, Mark Lowry wrote:
[...]

What are everyone's thoughts on this? Is it worth initiating an enhancement request in Bugzilla?

IIRC, hugin[1] can align stacks of images.

Chris

1 - http://hugin.sourceforge.net/

Mark Lowry
2007-05-03 03:19:04 UTC (over 17 years ago)

Three point layer distortion mapping feature?

--- Chris Mohler wrote:

On 5/2/07, Mark Lowry wrote:
[...]

What are everyone's thoughts on this? Is it worth initiating an enhancement request in Bugzilla?

IIRC, hugin[1] can align stacks of images.

Chris

1 - http://hugin.sourceforge.net/

That's sort of what I'm talking about. The problem with that is that the two images/layers are merged by hugin, meaning there is no chance for any masking or individual treatment of the layers after the mapping has been applied. You may have a passerby in one shot that isn't in the other shot and you want to mask him out, or the lighting might have changed and you want to tweak that ... you get the idea.

___

GSR - FR
2007-05-03 04:21:50 UTC (over 17 years ago)

Three point layer distortion mapping feature?

Hi,
vabijou@yahoo.com (2007-05-02 at 1819.04 -0700):

That's sort of what I'm talking about. The problem with that is that the two images/layers are merged by hugin, meaning there is no chance for any masking or individual treatment of the layers after the mapping has been applied. You may have a passerby in one shot that isn't in the other shot and you want to mask him out, or the lighting might have changed and you want to tweak that ... you get the idea.

http://hugin.sourceforge.net/docs/faq/#pano_gimp_layers and GIMP can read some PSDs, so you could try too.

GSR

Tom Lechner
2007-05-03 05:29:55 UTC (over 17 years ago)

Three point layer distortion mapping feature?

On 05/02/2007 01:53:42 PM, Mark Lowry wrote:

A plug-in that takes three control points on a layer and then distorts the layer (by scaling, translating, rotating, and stretching) so that those points end up on three other identified control points would be very useful
......
Having the ability to place
the control points and then tweak their position by dragging them while observing the live feedback would be ideal.

What are everyone's thoughts on this? Is it worth initiating an enhancement request in Bugzilla?

That is something I would use just about every time I use the Gimp. See this bug report in which I roughly sketched out how I'd use such a thing (i've refined it in my own program a little, but it's basically the same). It calls for a three point transform defining an affine transformation:
http://bugzilla.gnome.org/show_bug.cgi?id=164828

I personally wouldn't mind seeing some such tool completely replacing the separate rotate/scale/shear tools. I started to develop such a tool, but I keep getting sidetracked..

Also see this bug report about adding a "free transform" tool: http://bugzilla.gnome.org/show_bug.cgi?id=138462

I've also been (very, very) slowly making a tool to stretch around images using some form of bezier patch within the Gimp, which is relevant for the following bug report. Too many other projects getting in the way!:
http://bugzilla.gnome.org/show_bug.cgi?id=338888

Tom --------
http://www.tomlechner.com

David Hodson
2007-05-03 10:58:59 UTC (over 17 years ago)

Three point layer distortion mapping feature?

Mark Lowry wrote:

[...] But the stretching function that is required to help account for variations in lens distortion due to slightly different image centers (from hand-holding) is not possible.

You might also find this useful:

http://members.ozemail.com.au/~hodsond/wideangle.html