I don't manage to deal with a mosaic image

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Roll'
Posts: 124
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Location: Toulouse, France

I don't manage to deal with a mosaic image

Post by Roll' » Fri Dec 11, 2009 4:08 pm

Hi everyone,

once again I need your help!
Well, for the first time, I am working on a little high definition image (16 shots in 3 rows) but I encounter some difficulties stitching it.
I had a french tutorial on how to make a mosaic image but the site is unfortunately out (the page was not found it says)... So I did an attempt at making my image on my own... whithout success (I got too many defects).

Does someone have a tutorial about this? I am afraid, I did a research within the forum but I have not found what I am looking for.


During my attempt, I treated the shots as I would have done for a classic panorama by opening up all my shots simultaneously but I reckon that is the wrong way. I wonder whether I must stitch each row separately, then stitch the different rows together... but if it is so, I would have a twisted final image, haven't I?

Thanks for your help and sorry for these very novice questions


Arnaud

maxlyons
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Re: I don't manage to deal with a mosaic image

Post by maxlyons » Fri Dec 11, 2009 10:09 pm

Roll' wrote:Does someone have a tutorial about this? I am afraid, I did a research within the forum but I have not found what I am looking for.
Here's my (old) tutorial on how to manually create a mosaic with PTAssembler. Much of what I describe in the tutorial can now be automated by programs, but the general approach is still valid.

Here's another one written by Joe Beda.

During my attempt, I treated the shots as I would have done for a classic panorama by opening up all my shots simultaneously but I reckon that is the wrong way.
You should add all images into one project. As far as PTAssembler is concerned, it really doesn't care about the relative position of the images (e.g. in a single row, or multiple rows). In fact, there is no concept of "rows" in PTAssembler.

Max

Roll'
Posts: 124
Joined: Thu Jul 16, 2009 5:30 pm
Location: Toulouse, France

Post by Roll' » Sat Dec 12, 2009 5:11 pm

Thanks Max,
maxlyons wrote:Here's my (old) tutorial on how to manually create a mosaic with PTAssembler.
maxlyons wrote:You should add all images into one project. As far as PTAssembler is concerned, it really doesn't care about the relative position of the images (e.g. in a single row, or multiple rows). In fact, there is no concept of "rows" in PTAssembler.
so I use the good way to stitch my high definition image... but here are two screenshots to show you the problem.

after working on the 10 first shots (2 rows), the photo looks nice.
Image

the same pano after adding and optimizing the third row of images (do not take account of the unstitch shot in the middle)... the assembling looks pretty bad.
Image

I did another try on a different pano with 3 rows of images and the result is quite similar. I had a nice assembling for the two first rows but had not with the third one.


Arnaud

maxlyons
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Post by maxlyons » Sat Dec 12, 2009 6:25 pm

It is impossible to say without more information (e.g. project file and images). However, my top 3 guesses would be:

1. Bad (incorrectly positioned) control points
2. Incorrect lens projection
3. Incorrect lens FOV

Max

Jim Z
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Post by Jim Z » Tue Dec 15, 2009 12:19 pm

Roll'

I have the 'same problem' frequently. The problem is that there are not good control points in the pictures of the sky; the top row of pictures.

My way to deal with it is to use the Page 4 manual optimization.

Use the 'check boxes' to 'not include' the problem images, for the start of the project. After the first two rows are made perfect, use the 'check boxes' to add-in the problem images, and put them in their places.

First, un-check the "use control points from" and the "yaw, pitch, and roll" check boxes for the images from the top row. Use the 'manual optimize' button to get a good optimization of the images in the first two rows (exactly what you have in the first screen shot).

Next, un-check the yaw, pitch, and roll check boxes for the pictures in the first two rows (that will 'save' the optimization of the first two rows) and lleave 'checked' the "use control points from" check boxes for the images in the first two rows .

Next, 'check' the "use control points from" and the 'yaw, pitch, and roll' check boxes for any of the pictures in the third row that have good control points, the two pictures in the third row that include the light posts probably have good control points. Use the 'manual optimize' button to optimize those pictures.

Last, for the pictures of the sky that don't have control points, you have to interpolate aproximate values for the yaw, pitch, and roll of those few images, and assign those numbers (type them in) on Page 1. Roll is 0 degrees (close enough). Pitch is the same as the pitch numbers for the two images with the light posts, in the third row (close enough). Yaw is the same as for the images below, the first image in the third row is the same as the first images in the first row and the second row (close enough).

Also, instead of doing the interpolation and numbers to assign yaw, pitch, and roll positions for the problem pictures of the sky (the pictures that don't have good control points), you can manually put two control points in each of the problem images, in aproximate locations that will get the images optimized and positioned in the pano. It's beyond my explanation ability to tell you how to do this; if you use your imagination and some thinking about how the optimization works, you'll see how to do this. It's very quick; a couple of 'clicks' and that puts the picture in it's place.

Max, and others can comment on this: I think PTA will automatically interpolate the positions of pictures that don't have control points, but I don't remember the details of that feature.
Jim Z

Roll'
Posts: 124
Joined: Thu Jul 16, 2009 5:30 pm
Location: Toulouse, France

Post by Roll' » Fri Jan 15, 2010 4:39 pm

Sorry for the late...

Thank you very much Jim Z, I am going to try this!
maxlyons wrote:However, my top 3 guesses would be:

1. Bad (incorrectly positioned) control points
2. Incorrect lens projection
3. Incorrect lens FOV
Yeah, I have bad control points after adding the last row of images, this what I did not understand...
And I also noticed I have more defects using a rectilinear projection than a cylindrical projection.

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