PanoTools mailing list archive

Mailinglist:PanoTools NG
Sender:Bostjan Burger
Date/Time:2009-Dec-11 08:54:50
Subject:Re: Gigapixel, handheld...


PanoTools NG: Re: Gigapixel, handheld... Bostjan Burger 2009-Dec-11 08:54:50
Great story and excellent mountain panorama! You were heavy loaded with
the lenses ;)
:) Bo?tjan
--- On Thu, 12/10/09, Erik Krause <#removed#> wrote:

From: Erik Krause <#removed#>
Subject: [PanoToolsNG] Gigapixel, handheld...
To: #removed#
Date: Thursday, December 10, 2009, 11:39 PM




A multi viewpoint, three different focal length, handheld spherical 


I didn't plan to make this one. It was just an experiment, from multiple 

points of view (literally ;-)

Me and my family climbed the Sidelhorn near Grimsel pass in Switzerland 

this summer (the kids had much fun searching for quartz crystals) and I 

had my usual camera rucksack with me - no pano head, no tripod. From the 

summit there was a magnificent view all around, with two of the most 

impressive mountains over 4000m in the Bernese range (Finsteraarhorn and 

Lauteraarhorn) , the Matterhorn far in the dust and the Furka Pass, Uri 

granite mountains and the Rhone glacier in the east. And a view down in 

the upper Rhone valley (called Goms), to the Aare glaciers and lakes.

So I took a two row 360° panorama at 50mm from four different viewpoints 

around the summmit in order to avoid having the mandatory cross on the 

summit in the image and to view down in all adjacent valleys. I thought 

of something similar to those "from the tower without the tower" panos.

Because the sky was so nice I took an additional 360° cylindrical from 

the sky just above the mountains at 24mm focal length. I planned to make 

a high res cylindrical of the 50mm and 24mm images.

And because it was so nice I took an additional complete spherical with 

the 16mm fisheye, bracketed -2, 0, +2...

Month later when I was at my parents during autumn holidays I had 

nothing to do, but I had an old 2.4GHz 512MB notebook and the external 

disk with all the images from summer with me. So I set up some PTGui 

projects. It turned out that one exposure step from the fisheye was the 

same as the exposure I took the rectilinear images, and so I got curious 

whether it was possible to stitch the fisheye and the rectilinear images 

together and how far I would get with this tiny machine.

For ease of use I converted all images from raw to jpeg but with full 

resolution (20MP) and maximum dynamic range. To my suprise it was 

possible to load all 82 images into PTGui and align them. After some 

playing with blend priority the preview in pano editor looked pretty 

promising. I didn't dare to actually stitch, since PTGui reported that 

118 GB temp space where needed and the internal hard disk is 20 GB only. 

But now I wanted to make it, on my old machine at home or on a new one 

which I wanted to buy anyway.

When Max Lyons published the first gigapixel in 2003 my computer at home 

was already three years old and I thought I would never ever stitch a 

gigapixel on this machine. Max reported two days of optimizing. Well, 

PTGui took some minutes only to optimize the project on the poor 

notebook and not far longer on my computer at home. It was a challenge 

for my old Athlon 1.4 GHz, 1.5 GB - if it failed, there would be a new 

computer in several weeks...

I optimized all images together. Actually I had to set several control 

points manually between the different focal lengths, but after some 

iterations it optimized well. Then I split the project in three, one for 

each focal length. I stitched the two lower resolution ones to their 

recommended maximum size, and the high resolution one consisting of 62 

images to 46,000x23,000 pixel (maximum would have been 52,000x26,000) .

Stitching was ready after 14 hours (I was prepared to cancel the job 

after 36 hours) and delivered a 10 GB .psb file, containing the blended 

panorama and all individual warped images, which I needed to retouch 

huge parallax errors because of multiple viewpoints. So next came 

photoshop - would it open the file? Yes, it would.

It took about 1 hour to load, but working the masks with the brush was 

relatively fast. Flatting the image took more than an hour as well as 

saving the edited .psb.

When all three panoramas where more or less ok, I loaded them all in 

PTGui again in order to blow the lower resolution ones up and take 

advantage of blend priority and the PTGui blender. Processing took about 

12 hours again. Result was 8GB large (3 layers + blended) and took about 

the same times to open and process in photoshop.

During retouch work I discovered, that PTGui blender did a poor job on 

slight parallax errors in the high res version (structure doubling along 

the seam lines, which I know from ancient PTStitcher feather blending). 

So I decided to give enblend a chance. For this purpose I merged 

non-overlapping images into single layers. 62 layers where reduced to 7 

with the hope to speed up enblend. The -a switch does the same and 

usually speeds up enblend a lot. My assumption was that pre-assembling 

images would speed it up even more.

Enblend 3.2 crashed with an out of memory error, which is possibly the 

documented memory leak in this version. Enblend 3.0 succeeded after one 

night of processing and delivered a nice blended result almost without 

the double structures. I replaced the respective layer with the enblend 

result and could focus on the blending between the different resolutions 


After some adaptive contrast enhancements (large radius USM took about 2 

hours to complete and 1 hour "prepare to filter" on each layer) and hour 

long saving I had no chance to view the full resolution version locally 

on my computer. DevalVR refused with out of memory. I had to scale down 

by half.

Then I started FTP upload to 360cities, which took 7 hours. Next morning 

I had the first view and a shock: There was I white stripe in the pano. 

No, it was not 360cities image processing, it was me.

Searching back through the different versions was pretty tedious - any 

one took ages to load, but finally I found a stripe free version. The 

cause for the stripe must have been a layer copy in photoshop with shift 

key released too soon.

In the 3 hours I had each day there was hardly time to load the .psb, do 

one operation and save again. So it took another week until I had 

re-done the necessary editing and fixed some more stitching errors.

Ah, ok, the URL, finally. Have fun:

http://www.360citie sidelhorn- grimsel-swiss- alps-gigapixel

Who ever finds a stitching error can keep it for better days ;-) There 

surely are a lot more than I fixed. I'm not very satisfied with the 

transition between high and low resolution in some places while in other 

places it looks quite ok - but I hope no casual user will look down 

hires on boring stones...

best regards


Erik Krause







[Non-text portions of this message have been removed]


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