The View Up Here

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Archive for May, 2010

From UFO to Rubbish

Posted by Tom Benedict on 21/05/2010

Back in May, 2009, I brought my KAP gear to work at the summit of Mauna Kea, and during some free time at lunch I tried desperately to get my rig in the air.  I never did get to clip on the camera, but some of the guys across the way at Keck saw the kite and wondered why a UFO was flying over our dome.  Andrew Cooper, one of the guys at Keck, witnessed the event and wrote it up in his blog, A Darker View.

I have flow on Mauna Kea, and have done some surprisingly good KAP there, despite the prevalence of questionable wind.  During my first session at the summit, I got a good set of photos from summit ridge, but when I moved less than 100m to the south, the only stable point of flight my kite had was roughly 15m below my feet!  It’s not a trivial place to fly, and certainly isn’t for the faint of heart.  I’ve flown there a couple of times since, but it’s never something I take lightly.  During one flight I let out the full 500′ of line the FAA allows kiters to use.  So far as I know I may well hold the high altitude record for kite flying in Hawaii, and possibly the Pacific.  But reading Andrew Cooper’s blog let me add one more to my list:  My kite had been flagged as a UFO!

Last week I did a session much closer to home.  In fact, this time it was just outside the door at work.  Two of my kids go to school at Waimea Country School, a small private school in Waimea.  I’ve been trying to do aerial photography of the school for ages, but I was never able to get the vantage point I wanted because of a big stand of eucalyptus trees.  In case you’ve never run into one, eucalyptus trees grow from 80 to 100′ in height.  They’re big.  They block wind, they grab kites, and they’re generally un-fun to fly near.  I’d made attempts in the past, but something was always wrong.

This time everything went right.  The wind, which normally blows along the stand of trees, blew diagonal to them.  So I was able to launch, get the kite a good 2x higher than the trees, and clip on the rig.  Once I had the camera well over the trees, I walked over to the treeline and laced the line through the tree branches until I had it just where I needed it.

St. James Circle and Waimea Country School

The flight went off without a hitch.

As it turns out the school was in the middle of its last fire drill of the year, so all the students were lined up in the field in the upper left of the frame.  I sent a copy of the shot to the school’s headmistress, who got a big kick out of it.  She wound up showing it to most of the school and the parents of the kids.  But I didn’t hear the best part until later in the week.

This morning when I was dropping my daughters off, my younger daughter’s teacher ran up to the car to tell me how much she enjoyed seeing the photo.  But she confessed that she had no idea I was flying a camera at the time.  One of the kids in her class pointed up in the sky and asked, “What’s that?”  She looked up, saw a bit of green hanging up in space, and figured it was just a garbage bag fluttering around in the wind.  “It’s just a bit of rubbish,” she told him.

So now my 6′ rokkaku, which was sewn by a friend of mine at work and framed out by me, can claim the lofty title of being a kite, being a hexagonal levitation machine for aerial photography, being a UFO, and… being a bit of rubbish.

Hey, it’s all good so long as the photography works out.

– Tom

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

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 »

Beginning to Think about Sharpness

Posted by Tom Benedict on 10/05/2010

The weather prediction did work well, and the charts from the National Weather Service were right on the money when it came to figuring out where there would be cloud cover, rain, etc.  I wound up intentionally picking a spot with “bad” weather, but not so bad that it would result in precipitation.  There’s an old adage that bad weather is good for photography.  It’s true.  Bland skies are boring.  Skies boiling with clouds are interesting.  I opted for interesting.

It worked, and the photo session resulted in a number of good image sets for panoramas.  Few errors, good image spacing, and almost nine hundred images to choose from.  Excited, I blindly began stitching before really taking a close look at the images themselves.  The stitching went great, but a number of the images were unacceptably blurry.

This brought back an old goal I’d set for myself ages ago:  To have a program I could run on a set of images taken in a given location, and be told, in a quantifiable way, which were the sharpest of the bunch.

Doing a Google search on “image sharpness” or “how sharp is my image?” brings up all manner of pages describing the follies of attempting to apply numerical methods such as the mean transfer function to an image in order to judge the sharpness of the lens involved.  It brings up other cautionary articles that urge people not to attempt to quantify sharpness in any sort of repeatable scientific manner since it depends so much on the source image being used.

I’m not trying to measure the quality of my lens.  I’m trying to find out which shots I screwed up, and cull them without having to wade through a zillion shots!

I poked around a little, and found something that appears to work.  With a lot of my image processing work, I tend to turn to ImageMagick, a set of command-line tools for image manipulation that will run under most operating systems.  I use them under Linux at home, and on either Linux or Cygwin at work.  They’re flexible, powerful, often dog slow, but they almost invariably get the job done.

In this case I wound up using two tools: convert and compare.  To measure sharpness, I decided to make a blurry copy of an image, and find out how much damage was done.  If there’s no big change, the image was likely blurry to begin with.  If there’s a huge difference, chances are the image was pretty sharp, and the blurring action did a lot of damage.  So here’s how I did it:

convert -blur 2 source.jpg source-blur.jpg

compare -verbose -metric RMSE source.jpg source-blur.jpg source-diff.jpg

This spits out a number representing the root mean square error between the source and blurred images.  It also results in an image file showing that difference.  For my purposes I didn’t want to keep the blurry or difference images, so I deleted them after they were generated.

I ran some tests on the set of images I did over the weekend, and it appeared to work quite well.  I can’t say what number represents “sharp” or “blurry” because what those articles said is true: it depends too much on what the source image is.  But for a given set of images I can run this test, associate a number with each image file, look through a range of images, and determine what I’m willing to work with.  At that point it’s a simple matter of rejecting whichever images have an RMSE number lower than my threshold, and retaining the images with an RMSE number higher than my threshold.

The only down-side to this is that it’s time-intensive to run: upwards of 20 seconds per image.  It doesn’t seem like much, but once you get up to 800, 900, or 1000 images from a single shoot (typical for a panorama-intensive session) this starts to drag.  Nonetheless, with ImageMagick it’s possible to script the whole mess, set it running, and walk away until it’s done.  Sometimes computers really can make life easier.

So far tests is as far as I’ve gone with this.  But once it finishes running the software on the set from this weekend, I’ll be in a position to try using the information to build sharper panoramas with less work.

– Tom

Posted in Kite Aerial Photography, Photography, Software | Leave a Comment »

The Next Hurdle – Weather

Posted by Tom Benedict on 06/05/2010

I finally weighed my new rig.  I was right.  It’s not too much more than my old rig, but it’s still significant.  The camera + batteries + lens hood came in at 405g.  The new rig + batteries + legs came in at 537g.  Total flying weight added up to 942g, a significant bump from the ~850g I used to fly with.  Still, the extra ~90g of weight offers a lot more capability for the kind of shooting I seem to be doing.  Well worth it.

The next hurdle appears to be weather and everything else associated with it.  Last weekend I did get out with my rig, but didn’t get a lot of photography done.  I found nice subjects, but the weather wasn’t cooperative.  Ho hum.

This is nothing new, and this is nothing specific to KAP.  Ask any photographer, and they’ll tell you that as soon as they see a great scene setting up, the light changes.  Or the clouds roll in.  Or the clouds roll out.  Or something happens to make the shot not quite what it could’ve been.

I’m no different.  Last Saturday morning I got out and tried valiantly to out-distance the heavy overcast that was making the skies around Waimea absolute blahsville.  I drove almost an hour out Mana Road, and never got out from under the clouds.  In the end I gave it up as a bad idea and came back with what ground shots I got.  Later that day the family and I took off to photograph the lava flow at Kalapana.  The weather was fantastic, but the lava flow had shifted, and the folks working security moved the barriers back to the point where you couldn’t see anything at all.  We finally called it a day and went back to Hilo to catch dinner before driving home.

But the weather at the house was overcast the whole time, so I can’t say we made a bad call.  Just an uninformed one.  This set me on a mission to find better tools for predicting weather for photography.  So far the best I came across is a site run by the National Weather Service.  It offers a variety of weather maps for the various islands of Hawaii, including one that indicates the extent of the VOG cloud coming out of Halemaumau Crater.  Combined with the wind maps I already rely on for flying kites, this may just be the best guide for where to find photogenic conditions for doing landscape photography on the Big Island.

I should have a good opportunity to test this over the weekend.  My daughters have a social agenda that spans all of Saturday, so my wife offered to run them around, and asked me to take care of my son for the day.  We both looked at each other like we couldn’t believe our good fortune!  My son has been my companion on more photography outings than I can count, and he’s as excited at being able to go somewhere new as I am.  So I’m using the NWS maps, my list of sites I’d like to do photography, and the Mauna Kea Soaring wind maps to plan our day.

Maybe this time we’ll have better luck.  Or maybe this time we’ll plan a head and make a little luck for ourselves in the process!

– Tom

Posted in Hawaii, Photography, Weather | Tagged: , , , , , | Leave a Comment »