Category: KAP

The KAPtery has moved

MiddBann2k1Today the KAPtery moved to its own site: KAPtery.com. This frees up my personal site (fastie.net) for other things, but most importantly offers you a much better place to learn about 3D printed camera rigs for aerial photography. The commerce part of The KAPtery should also work better — buying kits and parts should be easier and more secure.

Titan 2 launch

Teddy launching the Titan 2 under a Flowform 16.

Teddy launching the Titan 2 under a Flowform 16.

I almost didn’t make it to the farm yesterday because 1) one of my A590s died, 2) the old CHDK sync mode does not work with A590s, and 3) it took me a while to install and learn how to use the new CHDK. Teddy almost didn’t make it because I was not sufficiently explicit about which gate I meant and he waited at the other gate. But we were flying the Sutton Flowform 16 by 5:00 PM in a janky 15 mph north wind with gusts of 20 mph. The Titan 2 Rig made its maiden flight with two A590s triggered by an MK111 timer.

The Titan 2 Rig with two A590s triggered in sync by an MK111 timer.

The Titan 2 Rig with two A590s triggered in sync by an MK111 timer.

One of the A590s was full spectrum (its IR block filter had been removed), and it had a 720 nm IR filter in front of the lens. So that camera saw mostly near infrared light. I white balanced that camera on grass, and the photos have a little color in them. We took 565 pairs of visible/infrared pairs over the Middlebury College Organic Farm. The cameras were aimed straight down, but the wind was swinging the Picavet quite a bit, so we got lots of slightly oblique photos, and more than 100 of the pairs were before or after the flight part of the flight. The shutter speed on both cameras was locked at 1/800 second at ISO 80, and most of the photos were taken at f 2.8. Some of the NIR photos were taken at f 2.6 (the max aperture), but there was not much difference in exposure between the two cameras. About 80% of the photos have no conspicuous motion blur.

Kite’s eye view

In the late nineteenth century, hand drawn “bird’s-eye maps” were a revelation to earthly New Englanders. When exotic hot air balloons were the only way to gain such a perspective, enterprising artists just imagined what a bird might see. The customers for these maps lived and worked in the buildings depicted, so these are probably placed with some accuracy, relying on existing maps for data. It is the details of the rest of the landscape that were recorded nowhere else. In the 1889 drawing below, cleared fields, orchards, and shrubby growth nearly to the top of Hogback Mountain confirm the wisdom that in 1850 the entire slope, like others all over Vermont, was probably cleared of trees. Today, the young ages of the trees tell the same story, but an old bird’s-eye view is still a revelation.

Grave images

Chopping hay below the Fled as I walk alongside.

Chopping hay below the Fled as I walk alongside. Click images to enlarge

My town’s cemetery committee would like to have maps of the grave stones in the three town cemeteries. The late Fletcher Brush cataloged the headstones in each cemetery in the 1990s, and probably made hand drawn maps, but it would be nice to have more official versions. I was asked on Thanksgiving about helping with this mapping, and the next day was beautiful AND had a nice south wind. Flying a kite over the cemetery in the village requires a south wind, and the row of overhanging locust trees along the edge makes late autumn the best season to image all the headstones from above. So I couldn’t resist exploiting what might be one of the last good opportunities to image this site for a long while.

Practice

Self portrait

I have lost a kite, but I have never lost an RC transmitter (around neck). This was taken during one of the first short-lived launches.

The winds have been light this week as the peak colors have been waning and my KAP pack has been poised by the door. I finally had to ignore the “4 mph” reports at WeatherUnderground and WeatherSpark and just go. I went to the hay field south of the Salisbury village where the south wind might push the kite toward the village center. There were some gusty spells that lifted the KAP rig just high enough so that I had to frantically reel it in when calm returned. Attaching and detaching the Picavet in a hurry requires more practice than I have had, and I surpassed my own record for making nasty tangles that included Picavet line, kite line, and alfalfa. At one point I didn’t have time to take off the Picavet as I wildly pulled the line in hand-over-hand, laying it across the field. After untangling (not my favorite thing), I called it a day, disassembled the Fled, and headed back across the field to the pack. When I got there the wind had picked up, so I assembled the Fled, threw it into the air, and had the rig attached when I noticed that I had left the RC transmitter out in the field — out in the huge field of alfalfa and grass that is at places a foot taller than the transmitter (the thing around my neck in the photo above).

Over Middlebury

I flew the Levitation Delta for 20 minutes before I had the courage to attach the KAP rig.

Last month I went to the Middlebury Farmers’ Market at Marble Works for the first time ever. My garden had been suffering some scurrilous blight and I was about to feed 10 people for the LEAFFEST weekend. I looked along the row of vendors to the steeple of the Congregational Church beyond some trees and realized there might be enough space to launch a kite there. A west wind would take the kite the length of the lawn and then over toward the church on the “Green,” the village commons. This could offer a unique view of the village center. But the wind almost never blows from the west here due to the north-south trend of the Champlain Valley. Other wind directions would make the flight less rewarding and the launch and landing more risky, and I had never flown a kite from such a small area surrounded by so many power lines, buildings, trees, river banks, and busy roads, so I assumed I would never fly there.

Downlink

Special parcel (Gift) for Mr. Fastie

Special parcel (Gift) for Mr. Fastie

Twice this year I walked around for more than an hour flying a kite-lofted camera that I thought was taking photos, when in fact it was just fooling me into getting exercise. On the first occasion the shutter controller battery died, and the other time the camera just got confused and stopped shooting. I think I sent radio commands to shoot too frequently and it decided to take a nap. This happened another time as well but I happened to reel everything down after only 20 minutes of not taking photos while I was jogging here and there. I have modified the controller so the battery lasts much longer, and I have learned to be patient when sending radio commands, but I am certain that the rather fragile KAP rig electronics will surprise me again with their unexpected inactivity. So I have been looking for a way to monitor the camera operation from the ground. I have been brainstorming with some friends about how to do this, and Don Blair, a physics graduate student at UMass has been prototyping an alert system based on a $20 pair of walkie-talkies. I couldn’t stand hearing about all the fun he was having in Amherst using MOSFETs to remotely push the walkie-talkie PTT button, so I decided to build my own solution.

Sprucing up the hills

The Fled overflies as I reel it in.

The Fled overflies as I reel it in.

It has been 14 years since we set up our first study plots south of the Alaska Range. I just returned to Fairbanks from a week-long trip to re-census the plots located above the upper forest limit at the Canyon Creek and Monahan Flats sites. There were a few scattered spruce trees and a total of a few dozen spruce seedlings marked with numbered tags in the quarter-hectare plots in 1998. The trees have not changed much, and only 8 to 10% of the seedlings have died. The surprise was the number of new spruce seedlings that have established in 14 years.
NIR/VIS KAP rig

The NIR modified and normal A495 cameras with AuRiCo controller. Synchronous, vertical photos were taken every 16 seconds.

Seedling density increased by a factor of 2.9x at Canyon Creek and 2.2x at Monahan Flats. The similarity between the two sites suggests that the seedling invasion may be widespread. These seedlings have a lot to endure before they become trees, but if similar numbers of seedlings continue to establish and many of them become trees, these plots will no longer be above treeline in 50 years.

I was able to get some aerial photos of most of the plots after I had marked each seedling with pink flagging. I flew a dual camera KAP rig with normal and infrared-modified cameras lofted by a kite. I will be experimenting with false color IR (NRG) and NDVI images which can be created with information from both cameras.

Chatanika Dredge

Radio Control

I flipped the joystick 1200 times to trigger the shutter (the 4 GB SD card filled up 10 minutes before I pulled it down).

The S95 captured 1170 photos in 1.5 hours while the Fled flew over the relic Gold Dredge #3 of the Fairbanks Exploration Company (F.E. Company). It was built in place in 1927-1928 and dug its own pond which it moved around until 1958. Hundreds of acres of the Chatanika River valley were turned into these concentric ridges of tailings as the placer gravels were devoured by the floating dredge and disgorged by the systematic arcs of its conveyor arm.

Swamp NDVI

On May 5 my infrared KAP rig made its first photographic flight. The shutters of two Powershot A495 cameras, one modified to record only near-infrared (NIR) light, were triggered every 10 seconds by an AuRiCo KAP controller. The Levitation delta kite hoisted the rig over the northern edge of the Salisbury Swamp, VT. In about 1.5 hours, 420 synchronous pairs of normal and NIR photos were captured. It has taken a while to process just a fraction of these images, but the results are promising. First, some kite porn:

Unexpected Panorama

KAP over the Kame terrace from Petri's field

Note the Henry's Handle hanging from the belt. The kite line is cleated to that while I attach the Picavet and run through the pre-launch checklist.

The huge kame terraces in my town support a dry-tolerant forest of oaks, beech, and red maple, and as the new leaves emerge it is easier to tell the species apart at a distance. So I have been hoping to fly a kite over the terraces in early May and see if the trees delineated the terraces. The wind was gusty today, but it was supposed to calm down a bit in the afternoon, so I hiked up the hill and launched the nine foot Levitation delta. It was after 6:00 PM when I first triggered the S95 with the Futaba transmitter, and the light was wonderful even if the wind was not. It mostly cooperated until it slowed down enough to send me running upwind barely fast enough to keep the line out of the trees. But I had 900 feet of line out for a while and the camera was well out of the clearing were it could see the tree tops as I never had.