BlueMantra
Posts: 4
Location: New York, United States
Registered: 28 Oct 2005
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Please Help! PTGui 5.4
Posted: 31 Oct 2005 at 15:34 GMT
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Hello All
I am using a panohead to take a picture of a large NYC building. Quality of final image is a high priority. I am using the trial version of PTGui and I am VERY VERY VERY VERY VERY impressed to say the least!
PTGui looks like a fantastic tool for stitching panos, however I have some questions:
1. Considering that quality is an important aspect of my project should I or can I use TIFF (files are so big) format in PTGui instead of JPG?
2.My project is very large with about 200 images. Do all the images need to be loaded at once? I have been able to successfully create vertical stitched portions of my final image. I guess my question is when you have large number of images what should the workflow be? Where do you start? Do I assemble columns or rows and then stitch the columns or rows?
3. Why does PTGui reduce the size of my images after it has stitched them? I stiched a a vertical column of images the original width of the images is 3,504 bytes given overlap I expect the height of the combined images will not be additive but why do I end up with a much smaller image width???
4. I have 200 images because I shot with an overlap of about 30% horizontally and 50% vertically. Because I used such a large overlap vertically it is possible for me to attempt stitching of images with 25% only overlap.
When I try to do this, PTGui correctly matches the control points and appears to stitch perfectly but I end up with a very small image surrounding with black????? What is happing here?
5. I stitched a vertical column of about 10 images. PTGui stitched it perfectly but rotated the stitched panorama into a horizontal position. Again the image size was very very tiny - like a thumbnail?? What gives?
I only started using PTGui yesterday. But after trying Image Assembler(not very good) and PTAssembler(probably driver error here), PTGui appears to have incredibile potential.
Please any and all help is very much appreciated! Thanks in advance.
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BlueMantra
Posts: 4
Location: New York, United States
Registered: 28 Oct 2005
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Re: Please Help! PTGui 5.4
Posted: 31 Oct 2005 at 17:51 GMT
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Ok for questions 1 and 4. I have found some answers. PTGui can use TIFF. I found the answer to why the small image inside of large black area. I think when the field of view has an incorrect value. I will have to try again.
Any help with the other questions.
Thanks
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GURL
Posts: 41
Location: Grenoble / Isère, France
Registered: 7 May 2004
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An answer to point 2)
Posted: 31 Oct 2005 at 19:15 GMT
updated: 31 Oct 2005 at 19:19 GMT
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If you stitch your images row after row first, you will not be able to get a good final stitch of the intermediate rows using any of the available projection modes (rectilinear/flat, cylindrical and equirectangular/spherical). Perspective in the top and bottom rows would not match...
If you stitch your images column after column first and do not use rectilinear projection (but the cylindrical or equirectangular one) the final result you will get when stitching all the columns together could be an excellent one.
Here is a discution about doing that on Max Lyons forum: www.tawbaware.com/forum2/viewtopic.php?t=826&high... (under the name Big mosaics on small computers.)
 Besides that, it's a terrible idea to begin using PTgui (or any other stitcher) for a 200 images project!
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John Houghton
Posts: 3487
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: Please Help! PTGui 5.4
Posted: 31 Oct 2005 at 19:44 GMT
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BlueMantra said: 5. I stitched a vertical column of about 10 images. PTGui stitched it perfectly but rotated the stitched panorama into a horizontal position. Again the image size was very very tiny - like a thumbnail?? What gives?
Beware of using automatic modes in any stitcher. They tend to make assumptions about what you want that are frequently inappropriate. In the advanced mode, you have all the control you could wish to make the stitcher produce your panoramas in whatever orientation you like. For a massive project like this, it is essential that you first find your way around the stitching process using smaller projects, as Georges suggests. The key thing to understand is the optimizer, which must be run with manual control to use it effectively. Read this guide when you have some time to spare:
homepage.ntlworld.com/j.houghton/optitute.htm
John
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BlueMantra
Posts: 4
Location: New York, United States
Registered: 28 Oct 2005
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Re: Please Help! PTGui 5.4
Posted: 1 Nov 2005 at 4:24 GMT
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I would like to thank both of you for your advice. I suceeded in stitching two perfectly vertical columns of my subject. Then I tried to put both of them together only to find out that they had different perspectives. 
Patience grasshopper....right?
So thanks for the links. I realise the folly of my approach and It is time for me to start from basics an learn about panoramas 101. Both of you have great websites! PS Gurl I wish I could read French your website looks very interesting.
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