Changing crop changes stitching success

[AndyMo905]

Hello - The Assistant created a perfect stitch of 3 photos, but I wanted more than the auto-crop.  However, when I changed the crop size (to anything outside of autocrop) the saved file has stitching errors (eg. a vertical post that is now split into two).  If I go back to the auto-crop and re-export, it's fine.   Any ideas on what is happening here ?  Thanks in advance.

[AndyMo905]

Here are some images of what is happening:

Using the Assistant with auto crop gives a good preview (the post in the middle forefront is in one piece):

saved image:

but if i change the crop boundaries to get more from the bottom of the image:

the resulting saved image has a big error on the front post:

here are the control points:

its frustrating LOL.

[T. Modes]

Hi,

talk2...@gmail.com schrieb am Montag, 11. Januar 2021 um 14:17:29 UTC+1:

Hello - The Assistant created a perfect stitch of 3 photos, but I wanted more than the auto-crop.  However, when I changed the crop size (to anything outside of autocrop) the saved file has stitching errors (eg. a vertical post that is now split into two).  If I go back to the auto-crop and re-export, it's fine.   Any ideas on what is happening here ? 

The seam finding algorithm (in enblend) is finding different seams in both cases because there are different image information available for the algorithm.

The main problem shown in the example is probably the parallax between the different images (you have probably not rotate the camera around the non-parallax point). To get a better result mask the pole in one image out, so enblend is forced to take the pole only from the other image. (This can be done in Edit>Panorama Editor, then go the mask/crop tab and mask the pole and stitch again.)

[AndyMo905]

Hi there,

But does the program not stitch the images together, and THEN crop the final image ?  I am not cropping the original images, i am cropping the final stitched result.

thanks for the reply

[T. Modes]

talk2...@gmail.com schrieb am Samstag, 23. Januar 2021 um 13:32:41 UTC+1:

Hi there,

But does the program not stitch the images together, and THEN crop the final image ? 

No. It process only the pixels in the crop area. Why should it process many pixels first and then crop them away. That would unnecessary increase the processing time.

[AndyMo905]

Great idea, but if the output ends up being different (especially from the preview) then all that saved processing time gets lost by me having to fiddle-with and re-do the stitching.  Or worse, as in this case, no output image at all.

[Klaus Foehl]

Hello,

it also works the other way round. Sometimes a glitch or bug from deep inside enblend rears its head, and a minute change of the output crop can make all the difference between fail and success. With your approach of blend first then crop this workaround chance would not be available.

Regards,

Klaus

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