Grid / Projection modification - customize

[Abrimaal]

Does Hugin allow grid (projection) modifications? Modifying an existing grid or creating a new one?

For architecture taken from very close distance (like a high building taken from the other side of a narrow street - often there is no other way)
I would like to configure a grid with
| | | | vertical lines straight, parallel
= = horizontal lines parallel too
but switchable between equirectangular / mercator / cylindrical scale or better adjustable with a slider like in panini general.

This projection will be useful for straightening architecture, below an example.
Where equirectangular / mercator are not suitable, because of curved horizontal lines.

A is the original photo
B is after straightening the || vertical lines in the rectilinear projection. The upper part, the tower is too tall because of the grid that consists of identical squares
C is after rescaling, still not good. The lower part became too small.

[bugbear]

Abrimaal wrote:
> This projection will be useful for straightening architecture, below an example.
> Where equirectangular / mercator are not suitable, because of curved horizontal lines.
>

> *A* is the original photo
> *B *is after straightening the || vertical lines in the rectilinear projection. The upper part, the tower is too tall because of the grid that consists of identical squares
> *C* is after rescaling, still not good. The lower part became too small.

The interface in Hugin does not use grids in the Gui - that's how Photoshop
and/or Gimp present it.

But it can certainly do projection correction; indeed it's a KEY
part of its fucntionality, since the multiple shots
of a stitched panorama have different perspectives.

You may find these tutorials helpful:

http://hugin.sourceforge.net/docs/manual/Perspective_correction.html
http://hugin.sourceforge.net/tutorials/perspective/en.shtml
http://hugin.sourceforge.net/tutorials/architectural/en.shtml

BugBear

[dex Otaku]

Have you tried Panini-viewer?  It does reprojections of single frames.

https://sourceforge.net/projects/pvqt/files/

[Abrimaal]

I can't run it under Win 10 64bit. I get a message at start
Unrecognised OpenGL version
When the window opens the next message is
OpenGL version: 4.5.0 NVIDIA 372.90
The software probably works correctly, but the display is black.

[Abrimaal]

This is almost exactly what I did except two details.

1. I was using the default optimizer (positions, incremental) instead of (y,p,r,b) or (y,p,r,v,b). Now the image looks perfectly.
2. I load two copies of the same image, find control points, optimize and save the final image as composed of a stack. 
I often load two different versions, they differ slightly by contrast or saturation or sharpness, or even both are the same image saved with different .jpg quality (let's say 95 vs 99). For the enblend / enfuse they are not identical and even a 1 Mpix image can be fused to 15 Mpix with less artifacts.

[Abrimaal]

Now it became simple when not using the simple interface, except setting the projection to rectilinear.
In the editor there are such steps
1. Add control points (when more than one image)
2. Add vertical and horizontal lines
3. Optimize (y,p,r,v,b)
4. Save the image (Create panorama in the simple interface)

It is important to know what we want to straighten, where to place the lines. Here is an example of two objects in one photo.
The gate is not parallel in the real world to the building. Trying to straighten both at once may lead to unpredicted results.
When straightening one object, we have to put control points and lines only on this object.