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Old Nov 14, 2005, 2:40 AM   #1
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Hello,
so far my panoramas look ok and I can correct the small/minor problems (mostly "ghosts").

But I still have something left and that's the problems at or near the joints of the used pictures. What I mean is - you stitch the single pics to get a big one and sometimes you'll notice the difference between the left and the right pic in a pano. It's another color/saturation/lightness/contrast, whatever - you see it. In the sky for example.

For me this problem is a bad one because my PC can't handle the postprocessing job for a big pano (have one with 12..16 4mpix pics atm for example) and gives "out of memory" errors or simply freezes.

So what I do is to "preprocess" the pics before stitching and this works much better for me. But in the sky I can see a "non-smooth" look when I stitched these pics.

So what do YOU do to bring back that smooth sky feeling? Any hints/tips for me?

Regards,
Th.

P.S. The main "blending" is ok - I use autostitch to do it - I just need hints for a final "touch up". Am using PSP9 if that helps.
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Old Nov 14, 2005, 7:40 AM   #2
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The first step is in shooting. Making sure that the exposure, white balance, ISO, ... are the same for all shots will solve many of those problems. Do not use a polarizing filter.

If your software has the option, output the pano as layers or as separate images ready to be stacked. That will allow you to pick where the stitch line goes. Picking where the stitch line goes often solves the problem. Or to blend the "frames" at the edges instead of having a fairly sharp edge.

As the last resort, there is the clone brush.

If you are going to be doing a lot of panoramas, you should figure out how to use Panorama Tools with one of the graphic front-ends: PTGui, PTAssembler, Hugin, ... Not easy to learn or to use, but well worth the effort.
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Old Nov 14, 2005, 2:52 PM   #3
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BillDrew wrote:
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The first step is in shooting. Making sure that the exposure, white balance, ISO, ... are the same for all shots will solve many of those problems. Do not use a polarizing filter.

If your software has the option, output the pano as layers or as separate images ready to be stacked. That will allow you to pick where the stitch line goes. Picking where the stitch line goes often solves the problem. Or to blend the "frames" at the edges instead of having a fairly sharp edge.

As the last resort, there is the clone brush.

If you are going to be doing a lot of panoramas, you should figure out how to use Panorama Tools with one of the graphic front-ends: PTGui, PTAssembler, Hugin, ... Not easy to learn or to use, but well worth the effort.
Thanks for all the hints. As for shooting - this is handheld. Your average holiday picture series of a nice scenery

I'll include my current work so you can see better what I mean. It's the sky that looks odd.
Now don't get me wrong - I think I didok so far given the images I had, here is one of the original images I used in that pano:



Maybe I am just asking for too much. Maybe I did something wrong. Maybe it's my PC, that forces me to postprocess these shots picture by picture, maybe something completely different...

It's not the joints of the pictures but the non-smooth appearance of the sky that bothers me. Everything else is as good as one can ask for I'd say.

An ideal solution would be a filter like thingie to select certain areas and "smooth" it out a bit, I am not sure if I am good enough with a clone brush to do this pixel-by-pixel...

Any ideas?
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Old Nov 14, 2005, 7:18 PM   #4
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There are two approaches. One is to use software that will analyze the image and even out the exposures. That takes a long time with a large pano if your computer doesn't have a lot of RAM and a fast processor.

The other is to take all of the pictures in the first place with your best guess as what the average exposure, white balance etc should be as Bill suggested. You need either a manual mode or a camera with a panorama mode that uses all of the settings from the first shot for the subsequent shots. You would pre-meter the first shot where you thought the exposure was your best average.

I made the mistake of buying a Panasonic S4 thinking the panorama mode would make up for not having manual exposure. I don't know what those guys were smoking, but panorama mode meters each shot separately. I was having to use software that took forever to even out the exposures until someone pointed out a trick that works with most cameras. Pre-meter the first shot and then use continuous mode – where you just hold down the shutter and it takes images at a fairly constant and slow rate. It isn't the same as burst mode, which is too fast on most cameras. Every camera I have tried it on uses the metering and other settings from the first shot in continuous mode.

My first impression looking at the panorama was that you used a polarizing filter. Light isn't evenly polarized across the sky and a polarizer isn't a good idea for a pano as Bill pointed out. Since Bill mentioned that and you didn't respond, maybe the exposures are just different.

You don't have to do a pixel by pixel workover. Use your color selector to pick a darker sky color for a particular area. Select the airbrush with a lot of feathering and maybe a 10% flow. Just darken the lighter areas. You could also do it the other way round by color selecting a lighter area and airbrushing in the darker areas. You might want less than 10%, but that usually works for me if I want to make multiple strokes without them showing. PSP might be different, so just experiment.


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Old Nov 14, 2005, 8:09 PM   #5
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Very goodjob of hand holding for a pano (lookslikethe top and bottom aren't cropped).

thkn777 wrote:
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...I am not sure if I am good enough with a clone brush to do this pixel-by-pixel...

Any ideas?
Don't try it pixel by pixel - use a fairly large brush with less than 100% coverage. Well under 100% with several overlays if needed.

Pretty muchwhat slipe said.
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Old Nov 15, 2005, 10:44 AM   #6
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EEK, yes, that might be the case. Not the pol.filter - but the different camera settings might be too much for the pano. I did my best to correct it via software but you can't do magic ...

It wasn't planned as such a HUGE pano - I just wanted to select 2-3 pics from the "best" area" or just have memories from the whole scenery. Especially with the strong backlight I feared I'd never manage to create a nice pano at that image part.

But I found that I can stitch it very well...

Hm will see what I can do... maybe some completely different treatment for sky and foreground - I tried a rather identical approach here...

Will keep you updated.

Th.
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Old Nov 15, 2005, 5:14 PM   #7
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hi, all my panoramics are hand held and hand joined in photoshop, contrast differences can be overcome as can anything.

i am more than willing to have a go at joining your pics for u if u are not happy with auto stitching software, i wasnt, as i to found it wasnt perfect



please take a look at my stuff on www.hd7.co.uk

its not a easy job to join them with photoshop but pretty straight forward to me cos i use it so much

that view is very very nice by the way..............wish id taken it
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Old Nov 15, 2005, 7:35 PM   #8
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Yup, all kinds of corrections can be made, and it is worth learning at least a few of those tricks.

It is even better if you don't have to use them.
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Old Nov 16, 2005, 1:47 PM   #9
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You guys are great, really. Thanks for all the nice comments so far. Yes it's handheld, cam is a Oly C770 UZ at wide end, no filters used. I just walked/climbed there and sat on one of the rocks when the scenery did hit me and I thought - hey - I can't do a wide lens shot (Oly C770 starts at about 36mm or so which is bad for this kind of pics) but I might go for a panorama! So I grabbed my cam and tried.

If I stitch the pics without any pre- or postprocessing it looks like this:


I started on the left and because I felt I wouldn't cover enough vertically I changed from landscape to portrait mode (to say so) after 3 pics or so. I had to be quick because I wanted to use my chance with the clouds hiding the burning sun so I got less backlight effects. Still there are a lot of it at the picture

So the stitching is ok - takes me half an hour or so (maybe 40 mins) with Autostitch and it's ok... but I want to prostprocess to bring out the darker areas of the pic as they would have shown up when I was only shooting NOT the sky - more colorful, more lifely and not covered in all those nasty shadows.

So what I did is I tried to postprocess the stitched pano but failed because my PC can't handle it at that size (about 15megs as JPEG, 13716x2590 at 16mio colors give 104.076kb in memory for a single pic). A single deconvolution filter run needs 25+ mins for one of the 16 single images each. Each "simple" filter (lightning, contrast, etc.) needs a long time or gives a "out of memory" error or kills the program or the whole PC.

So I tried to pre-process the pics one by one, separating sky and foreground and got single images (same procedures for each pic). When I stitch these pre-processed pics to my great dismay I get the pano from above:



Colors and stuff are nice overall... you know I want to print it at about 50x200cm poster-size and need a bit of that "wow" effect for a print that size. Only thing that bothers me is you can see a smooth blue gradient on the sky in the 1st pano and a distorted blue in the 2nd pano, although I used the same procedure of image manipulation on each single pic

At least I think so... wait... I have an idea.... uhoh... I have to check something...
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Old Nov 17, 2005, 3:30 PM   #10
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Olympus has a very good panorama mode as it locks all of the settings with the first shot. I pre-meter where I think the average exposure is.

The ONLY thing I have found the included Camedia Master software useful for is stitching. It flags the panorama shots with a number and you just drag them into a box in numerical order for stitching. I think you have to shoot left to right for it to work. It assumes you took the shots at the same camera settings and stitches very fast since it doesn't have to mess with different exposures etc. The Camedia software also requires very little overlap, so you can get a pretty wide panorama even holding the camera vertically within the 8 shot limit for panoramas. My C50 is limited to 8 panorama shots. The 770 is newer and might not have that limitation.

By "fast" I am talking maybe a minute for that pano in Camedia if you use panorama mode to shoot the original scene. And you will get no sky gradation problems shooting in pano mode because of its using the same settings for all shots.

For the pano you already have you seem to be ignoring the airbrush suggestion. The second shot is more dramatic and needs some help in the sky. It is almost impossible to adjust the individual images when you shoot in any auto mode other than pano.

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