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Posts Tagged ‘Panorama’

Panorama Workflow

Posted by Tom Benedict on 23/07/2010

I’ve had some opportunities to play with my camera on the ground as well as in the air, and to test a number of image sets on the software I’ve been using.  Two days ago my wife and I took our kids to Pololu Valley to go hiking.  On the off-chance the weather would be nice, I brought my KAP gear.  The weather was fantastic, with solid winds for kite flying, and beautiful partly-cloudy skies.  Time to play!

I ran about 5GB of images through the camera from various vantage points.  In creating the base images I tried to incorporate everything I had learned from the earlier experiments.  The resulting photographs turned out quite well, so I’m considering the new workflow to be a win.  I’m sharing it here in the hopes that someone else doing kite aerial photography will give it a try and take it even further.  Here are the details:

  • If you can shoot RAW, shoot RAW.  I can’t, but in the near future I’ll be able to.
  • Use Manual Exposure mode on your camera.  Set it on the ground, check it, and double-check the histograms to make sure you’re getting bullseye exposures.
  • Use at least 1/1000 second exposure speed.  I’m using 1/1250.
  • Use the slowest ISO setting you can to control noise.  This is of less concern with a DSLR, but every bit helps.  I made this set at ISO 80.
  • Use the sweet-spot aperture on your lens if possible.  My lens is sharpest around f/4 to f/5.  I couldn’t use this aperture and hold the other numbers, so my lens is wider than ideal.  But the benefits in noise at ISO 80 make this a reasonable choice.  I give up some sharpness for lower noise, and keep the fast exposure speed to avoid blur.

Once the camera is in the air, all my panoramas were made with the camera vertical.  With a KAP rig this either means building the rig around a vertical camera (Brooxes BEAK rig), or using an L-bracket on a conventional rig, or having a dedicated Horizontal/Vertical axis on the rig.  I recently modified my rig to add the HoVer axis, so this is the route I went.

The idea with this technique is to start the rig on a slow spin, and to trigger the shutter continuously.  This technique was developed by a French KAPer who goes by the name of Vertigo on the KAP forums.  With a sufficiently fast shutter speed, this works perfectly.  My A650IS does one frame every 1.1 seconds.  With a 10-second-per-rev rotation rate, this works out about perfectly.  I’m upgrading to a Canon EOS T2i DSLR in the near future, which has a much faster frame rate.  I’m planning to build an electronic release cable for this camera that will give me the same 1-frame-per-second rate my A650IS has so I can continue to use this technique.

  • Start the rig rotating at a rate that gives you adequate overlap between images, and minimizes motion blur from the rotation, given the camera’s shutter speed.
  • Once the camera is rotating cleanly (no see-sawing on rotation, no jerkiness in the pan axis, no swinging around, etc.) trip the shutter.
  • Make at least two complete orbits of the camera, tripping the shutter non-stop the entire time.  This is for a couple of reasons:  First, it gives you plenty of frames to choose from in case one is blurry.  Next, it gives you a range of random tilt angles that you can use to fill in gaps later on.  Finally, if the rig starts to move, the second orbit will still produce a clean panorama.
  • If you want to make a larger panorama, change the tilt after two orbits and make two more orbits at the new tilt value.
  • While all of this is going on, do everything you can to minimize camera motion.

This should produce a nice set of images from which to work.  You may well end up using them all, so don’t toss any of them!

I use Autopano Pro for stitching.  Some of the tricks I’ve picked up will apply to other packages.  But if you find yourself scratching your head and thinking, “No, I’ve never seen that,” don’t sweat it.  Your software is different.  Skip that part.

One of the first problems I ran into is that Autopano Pro deals really well with point features, but not very well at all with linear features.  For example, it’ll match up individual stones on a beach like a champ, but it will produce lousy horizons if the horizon is just water and sky.  It makes no effort whatsoever to correct for lens distortions if the bulk of the picture is water and sky.

The fix I found was to use PTLens to correct lens distortions before using Autopano Pro.  PTLens is a $25 plug-in for Photoshop.  Even better, it’ll run as a stand-alone program and will batch process hundreds or even thousands of images at once.  If you’ve got a block of images you photographed as fodder for panorama stitching software, it’s no problem at all to batch process them all to remove lens distortions.  Water horizons should now be ramrod-straight lines across the frame.

So back to the process:

  • Run the entire image set through PTLens to remove barrel distortion, vignetting, and chromatic aberrations, but nothing else.
  • Process the images with Autopano Pro, or the panorama software of your choice.
  • Do everything you can to get completely horizontal, completely straight horizons for water.  Nothing kills a pano faster than a grossly errant horizon.
  • Save as 16-bit TIFF images.  16-bit workflow can be a real PITA, especially on a smaller machine, but it hides a lot of ills when it comes to large-scale processing like Levels and Curves.

At this point I open up the images in Photoshop.  I’m still using Photoshop 7.  I’ll upgrade to CS5 as soon as I can afford it.  But for now it still does everything I need.  Want is a whole ‘nuther story, but as far as my needs go, it’s fine.

  • View 100% and check for stitching errors.  Repair all of these with the rubber stamp or heal tools.
  • If your kite line shows up in the image, remove it using the same tools.
  • If you cropped your panorama wide enough to have gaps in ground or sky, open up all the images that went into the panorama, as well as the second orbit you made from that same location.  Use the rubber stamp tool to pull patches from any and all of the input images to repair problems on the panorama.  (This is one of the best reasons to make a second orbit!)  Since you used a fixed exposure, you should be able to rubber-stamp these into the panorama with no changes necessary.
  • Once the panorama is defect-free, look at your levels.  If you did your job setting the manual exposure on the ground, the exposure should be dead-nuts on, or need very little tweaking.
  • Do all your dodging and burning at this point to get the exposure just the way you want.  This can involve lots and lots of time, depending on how meticulous you are with your exposures.  If you’re the kind of person who got into photography in the days of film, and spent your afternoons in the positive darkroom dodging and burning the same negative over and over and over, you may be on this step for a while…

At this point the bulk of the workflow is complete.  But I would advise you not to stop here.  In Photoshop under the File menu is a command called File Info.  Click it.  It lets you edit the header information associated with your image.  At the very least I would fill out:

  • Title – What is the name of the original file on your computer?  Leave out the extension since that can change without changing the image.
  • Author – Your name.  You’re the author of your image.
  • Caption – Describe the photograph clearly and concisely, and include enough information so that you could read it and know where on the planet you were when you made the photograph.
  • Copyright Status – Change this to “Copyrighted Work”.  The moment you tripped the shutter, your photograph was a copyrighted work.  Not marking this just sets you up for someone to use your photograph without your knowledge.  If you choose to license your photographs under the Creative Commons license, of course, you should set this appropriately.
  • Copyright Notice – Mine reads: Copyright © Tom Benedict
  • Date Created – The date you tripped the shutter on your camera to make the photographs that went into this image.
  • City / State / Province / Country – Fill them in.
  • Source – Give yourself some hints here.  Is it a straight shot?  Digital?  Film?  Stitched?  My digital panoramas are all marked “Digital-Stitched”.

The neat thing is that most of the photo sharing sites on the Internet will automagically read your header information and fill in their own forms for you.  You may still want to provide more information than this, but the base information will be there.

The even neater thing is that in the event someone downloads your photograph and puts it on their own site without your knowledge, your header information is indexed by most search engines.  Even better, when you challenge them and they claim the photograph as an “orphaned work”, you can demonstrate that they did not make an honest effort to find the photographer in order to ask for permission since your info is all right there with the image.

So that’s it in a nutshell.  How well does it work?  See for yourself:

Pololu Valley Wetlands 2

– Tom

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The Good and The Bad

Posted by Tom Benedict on 09/07/2010

The 2010 SPIE Astronomical Instrumentation conference was a blast.  We worked some seriously late hours, and all of us were dragging our tails by the end of it.  But the amount of information I came home with was…  for want of a better term, it was astronomical.  But that’s a post for another day.  This one is about the KAP I managed to do while I was there.

“Managed” is the right word to use in this case.  Sunset was at 8pm, and the only full day I had to do KAP was the Saturday before the conference.  I had some problems with my flight, so most of that day was lost.  Even so, it was the most productive day I had, from a KAP standpoint.  I wound up staying at the Porto Vista Hotel in Little Italy.  I highly recommend it for a couple of reasons:  1 – It’s a nice hotel.  That’s tough to beat.  2 – Close proximity to a lot of good KAPing.  3 – It’s in Little Italy!  As it turns out it’s also close to a camera store, which I didn’t visit, and a Blick Art Supply, which I did.  Twice.  It’s about a two minute walk to the nearest trolley station, and it’s only a few blocks from the Maritime Museum, which boasts some outstanding KAP subjects.  Unfortunately none of the KAP I did there really worked out.  This is the best of my efforts:

Maritime Museum

Further down, there were a number of other good subjects.  Some I wound up photographing with a pole, others with a kite.  By far the best KAP I had in San Diego was at the marina at Seaport Village:

Seaport Village Marina

The wind was steady enough to let me do some panoramas as well, one of which turned out nicely:

Seaport Village Marina Panorama

Heading back toward the hotel is the USS Midway and the statue, “Welcome Home”, which I photographed using a carbon pole:

Welcome Home

If you’re already taking framed kites with you, I highly recommend bringing a lightweight pole as well.  The carbon pole I use is a collapsible fishing pole intended for breem fishing.  It’s far from ideal, and the performance isn’t up to that of the higher end carbon fiber carp poles.  But it’s light, it’s portable, and it only cost me $20 at K-Mart.  I had no problems transporting mine, but even if it did take damage, it was cheap insurance against poor wind or restrictions on flying.  It also let me do some night photography in and around Little Italy:

Fountain in Little Italy, San Diego

Little Italy at Night

The only time I flew once the conference began was on a day when there weren’t any afternoon sessions I really wanted to attend.  Instead I grabbed my gear, got on the trolley, and headed over to the SDSU campus.  The wind was plenty strong, the weather was clear, and it should’ve been a fantastic KAP session.

It wasn’t.  The wind was strong but turbulent, and before I even got a camera up, my Dopero inverted.  I was in the middle of setting up my rig, so everything was clipped off.  I frantically tried to unclip my winder and line in time to let line out and try to save the kite, but I was too late.  The line came down across the Malcom A Love Library.  My heart sank!  I had no way of telling if the kite had hit the roof, or the glass dome just beyond.  I felt like an idiot.  Overwhelmed with dejection, I packed up my gear, reeled in the line, and walked over to see what the damage was.

Lo and behold, there was my kite dangling about halfway down the side of the building.  It was out of reach of my pole, but to my immense surprise it had inverted again just before landing, so it was sitting nose up!  In case you’ve never seen a Dopero, one attribute of this beautiful kite is that it is extremely stable.  Once it’s pointed in a given direction, it really likes to go in that direction.  It’s a little sluggish on reacting to changes in wind direction, which is one of the things that makes it an excellent kite for KAP.  I knew if I put some tension on the line, it would try to fly.  More to the point, it would try to fly straight up and off the library.

I went back out to where I’d been standing, took up all the slack I could, and heaved.  The tension in the line built as it stretched, then I felt two distinct yanks as the kite cleared the far side, and then the near side of the building.  A little shaken, a little wiser (I hope) I brought my Dopero down, packed it away, and sweated for a little while.

In the end I changed winders and switched to a 6′ rokkaku.  It wasn’t enough to lift the camera reliably, but I got some decent low-altitude KAP:

Flower Bed Outside Hepner Hall - SDSU

Love Library Plaza - SDSU

Love Library - SDSU

Shortly after I packed everything up, jumped back on the trolley, and got back to the conference for the evening session and poster presentations.  By the time I got back to the hotel, I was beat.  But a KAP session isn’t complete until the gear is checked, so I examined my line for fraying (surprisingly none!) and checked my Dopero for dings.  It got a small tear in the sail, which I opted to fix once I got home.  Other than that, I got away unscathed.

More to the point, I got away lucky.  The lesson was still learned:  If the conditions aren’t right, it’s better to walk away than to risk hurting someone, damaging property, or damaging your own gear.

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SPIE Poster

Posted by Tom Benedict on 08/06/2010

As with most of the projects I do for work, the SPIE poster didn’t work out 100% as expected.  Once I started going through the photographs and diagrams I wanted to stick on the poster, and figured in the size everything had to be in order to be readable at a distance, that 36″x45″ started to look awfully small.  And no matter how neat I tried to make it, that background texture of snow was just distracting.  So out went the theme of “cold” and in came the theme of “I have no clue what I’m doing.”

So I ran with it.

SPIE 2010 - Espadons PCC Poster

I really didn’t know how I wanted to lay the poster out, so I gave up and didn’t.  The text blocks were set on a page I tore out of a notebook and scanned on our Xerox Workcentre printer.  The photos were set in Polaroid-like frames I’d used for the KAP talk I gave a couple of weeks ago.  (True Polaroid frames are taller than they are wide.  These were tweaked to fit the aspect ratio of the photos.)  The graph and diagram were superimposed over the graph paper letterhead we use at work, likewise scanned on the Xerox.  The only traditional object on the poster is a JPG reconstruction of our monitoring web site for this cryosystem.  If the poster looks scattered, it’s because I was, too.

But in talking to people around the company, the feedback I got was that the approach actually worked.  The whole job of the poster at a poster session is to draw someone’s interest long enough for them to come over and talk.  Even if they come over to ask what the @#$^ I was drinking when I made the poster, that’s good enough for me.  If they want to talk cryocoolers, that’s fine.  If they want to talk poster layout, that’s ok, too.

The best part was when I brought my 11″x17″ test print of the poster home last night.  One of my kids asked what it was.  “It’s…  It’s my science fair poster!”  And know what?  It’s true.

– Tom

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SPIE and Poster Presentations

Posted by Tom Benedict on 15/05/2010

I work at an astronomical observatory on Mauna Kea on the Big Island of Hawaii.  Hawaii is also where I have done the bulk of my KAP work.  For the most part the two, work and hobby, rarely mix.  I sometimes do photography at work, sometimes even high-angle photography.  But rarely do I get to do KAP.  I can count those occasions on one hand without using all my fingers.  Still, I keep looking for opportunities and have fun every time I find one.

At the end of June a bunch of us are heading off to San Diego to go to the SPIE Astronomical Telescopes and Instrumentation 2010 conference.  I’m presenting a paper on the cryogenic cooling system for one of our instruments.  We made some fundamental changes in the system over the last two years, and the paper presents our results.  At a conference there are two ways papers are presented: oral presentation and poster presentation.  Oral presentations mean getting up on stage in front of an audience and taking your time slot to present your findings.  Poster presentations mean hanging up your poster, and during the time slot allocated for that group of posters it means standing in front of your poster and answering any questions people might have.

Oh yeah, I went for the poster presentation.  I’m not completely comfortable with public speaking, though I’m getting better at it.  But the real draw was the poster.  A poster!

The SPIE conference rules call for posters no larger than 45″x45″.  We have a large format photo plotter at work that can do 36″ wide prints.  I’m figuring on making a poster 36″x45″.  Most of the posters I’ve seen have been informative, most are easy to read, but very few of them have much in the way of pizazz.  Since my presentation is about a cryogenic cooling system and the instrumentation we put into place to monitor the cooling system, I don’t have much in the way of graphs but I have a lot in the way of diagrams and photographs.

And I also have every bit of that 36″x45″ that isn’t covered by words, graphs, diagrams, and photos to cover with whatever I want.  Yup, whatever I want.

Most of the posters I’ve seen use a color gradient wash as the background, or maybe a pastelized picture that’s related to the subject of the poster.  Not me.  I’m running with the whole “cold” theme, and I figured out how to work KAP into it.

Back in 2009 we had a particularly icy winter.  During one of our mid-winter instrument exchanges, things appeared to be working well, so at lunch I grabbed my KAP gear and headed outside.  The wind really was too tossy for good KAP, but I still came back with 1.3GB of photos to work with.  One set of images was good enough to make a nice wide panorama of the snow covered summit.  Sapphire blue skies above, white white snow below, snow covered cinder cones in-between, and the telescope where I work off to one side.  Perfect.

The rest of the background is going to be a snow texture extracted from the remaining photos in the set.  Hints of texture, but nothing too overpowering.  I still haven’t decided how much I’m going to carry the theme into the boxes that will enclose the various text blocks, diagrams, graphs, and photos.  I think going so far as to hang icicles around the text boxes is probably just a little too much.  But it’ll be fun.

It’s fun to mix work and KAP.  And any chance I get to make a print as large as 36″x45″ is just too good to pass up!

– Tom

Posted in Astronomy, Engineering, Hawaii, Kite Aerial Photography, Photography, Weather | Tagged: , , , , , , , , | Leave a Comment »

A KAP Rig for Panoramas

Posted by Tom Benedict on 30/04/2010

I finished the modifications to my KAP rig to give it an additional axis of rotation: plan.  With the flip of a switch, I can rotate my camera 90 degrees for doing verticals or for making vertical panoramas.  The additional axis was almost entirely constructed using parts from Brooxes.  The only custom part could be replaced with a slightly modified commercial part.  Here’s the axis as-built:

HoVer Axis

The modification didn’t really add that much weight to the rig, but it did add a considerable amount of bulk. I didn’t really pick up on how much until I rotated the camera to vertical:

Subtle as a Dump Truck

I modified my transmitter by removing one of the unused axes and installing a TPDT switch in its place. Two 10-turn 5k potentiometers wired on either side of the switch give me two independent set points I can switch between. One was set to position the camera horizontally, and the other was set to position the camera vertically. The 10-turn potentiometers allow plenty of room for fine-tuning and dialing the HoVer axis in really accurately.

Sit 'n Spin

I haven’t had an opportunity to fly it yet, but that should come over the weekend.  The only other modification I still need to make is to add provisions for my safety lanyard, which is shown hanging in the wind here, and to add Velcro safety straps for the camera itself.  My previous method for strapping the camera down would interfere with the new HoVer axis.

The parts used for the HoVer axis are a Brooxes Utility Frame, a Brooxes Deluxe Gear Guide, and a custom hub.  The reason for the custom hub was to provide a positive connection between the camera bracket and the HoVer axle.  Using a plain-shaft hub runs the risk of having the set screw come loose and the camera falling free of the frame.  So I made a hub with a threaded hole in the middle.  This screws onto the HoVer axle, and a set screw then locks it in place.  If you’d like to make this modification to your rig and don’t have a machine shop to make parts in, a good alternative would be to pick up a 1/8″ bore gear hub from Servo City, enlarge the bore, and tap it #8-32 to go on the Deluxe Gear Guide axle.

One unanticipated benefit of this is that attaching the camera to the rig is very straightforward now.  The camera can rotate in all three axes, so it’s a simple matter to flip the camera on its side, roll it back a little, and really get some easy access to the tripod screw.

I can’t wait to get this rig off the ground and see what Autopano Pro does with the resulting photo sets.

– Tom

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