Phase One iXU 180

Wednesday, 1 April, 2015

DPReview reports on the latest Phase One Industrial medium format aerial camera, the iXU180. This is a 10,328 x 7760 sensor at an optical size of 53.7 x 40.4. Using a bigger sensor means….more light collecting capabilities but at a cost. The pixel size is actually almost exactly the same as the Ricoh GR, what I consider to be a great KAP camera, however you get ALOT more pixels - in fact you get 64MP MORE with its 80MP sensor. Given the newer sensor in it you would also expect it to have marginally better sensitivity meaning it should perform slightly better in low light. Being an “as designed” aerial camera its also more robust. It supports a range of interchangeable lenses, but at 1kg for the body and 500g for the lens its not a light option.

Clearly a great product to fly with!

Amazon Prime Drone

Monday, 16 February, 2015

Clearly Amazon are very keen on the whole drone/UAv delivery thing…..the BBC reports on a recent FAA draft ruling that require operators to have “line of sight” with their kit. This pretty much puts paid to delivery for the time being. However expected this (air!)space to become crowded as a number of delivery operators will push for the this. I guess to start with we might see extended trials in some regions…. one to watch as it will clearly affect the wider UAV debate. And take a look at the Small UAV Coalition…. the only thing “small” is the UAV. Some big backers (see the members)behind this advocacy group…smiley happy website though!!

UAV Update

Wednesday, 27 August, 2014

Thought I’d provide a brief update on some UAVs I was observing during some collaborative work with Wagengingen. Below is a short video of the Altura Pro AT8 octocopter (see the Altura website). What amazed me about this kit is that it is at the more serious drone end of the spectrum. The payloads can be higher (1.5-3.0kg), but it was the speed and maneuverability that was remarkable, whilst flying time was good (~40mins).

If you want coverage as per a fairly traditional aerial photography mission, then a fixed wing drone is the one to go for. Wageningen have a Mavinci Sirius which, whilst at the lower end of the technology spectrum, is particularly adept at capturing high quality imagery over large areas.

Future developments are clearly going in the direction of better quality cameras, hyperspectral imaging, longer flight times, heavier payloads, and better stability. We are pretty close to “version 3” products now - I can’t remember where I read it, but the adage goes that you should wait for a version 3 product to get something that is beyond “early adopter” and fit for market. Tesla electric cars, Leica ScanStation, Microsoft Windows to name but a few. We seem to be at the stage with UAVs with improved reliability, lower cost and a slow rationalisation of the market from small vendors to fewer larger companies.

Definitely a “watch this space” moment.

This drone’s a’smokin!

Wednesday, 21 May, 2014

What a great story!!

UAVs and the law

Tuesday, 5 March, 2013

UAVs are starting to the hit the big time with everything geospatial and are driving a hardware, data and software revolution along the way (more in later posts, but think open-source designs, open source software, massive datasets). However their use in most western countries is tightly regulated - and rightly so. If someone is deploying a flying vehicle weighing several kilos that can fly at 30+ kmh then you’d like to think that it’s safely done. And that is perhaps where KAP has some advantages… it is tethered, relatively safe and in many locales unregulated.

And this is where many nations are starting to ponder the UAV conundrum…..New Hampshire is looking at extreme restriction which all but negates any use of UAVs. I wonder how many other countries/states will follow suit?

Perfect KAP camera??

Thursday, 20 September, 2012

Well, Nikon made a big splash by announcing the D600, the first consumer level full-frame (FX) DSLR (and plenty of reviews). Full frame is the key point and as cameradebate.com note, you get a bigger sensor which has four benefits:

No cropping of the image when using a 35mm compatible lens
Achieve shallower depth of field
Higher sensitivity and less noise (aka better high ISO performance)
Higher Dynamic range
Bigger and brighter optical viewfinder

The key point is that a full 35mm sensor is fitted in the lightweight magnesium alloy/polycarbonate body, almost the same as the D7000. This reduces the size and weight; its 760g as opposed to the 1000g of the D700.

Is this the perfect KAP camera? Well maybe - it has the high geometric fidelity and ability to use high quality lenses that we found when shooting with the D70. More importantly it has much greater sensitivity meaning that you can shoot at fast shutter speeds and high ISOs to obtain much sharper images, crucial for high quality photogrammetry. The ability to create high accuracy DEMs is significantly enhanced and the 24 megapixel resolution places it in a league of its own. Next step is to see if Nikon are willing to let me hang one underneath a kite!!

KAP Camera Coverage

Tuesday, 18 September, 2012

When mission planning for a Kite Aerial Photo (KAP) survey it’s useful to know the approximate coverage of each photo and pixel size. These parameters are basically reliant upon sensor resolution, flying height and lens type or more specifically:

-sensor size (width/height in millimetres)
-sensor size (width/height in pixels)
-lens focal length
-flying height

When I started my KAP work back in 2005 I wanted to calculate these automatically and Clive Boardman at Photarc Surveys kindly sent me an spreadsheet he used for mission planning. So I thought I would make it available as it’s incredibly useful. For my use I enter the the flying height which lets me see the image dimensions and pixel size. Enjoy!

KAPping in Delft

Wednesday, 4 April, 2012

I’ve just spent a couple of days delivering an introduction to KAP for MSc students at the UNESCO-IHE Institute for Water Education in Delft. More specifically it was a series of lectures, fieldwork and practical around this topic area, but starting more generally introducing aerial photography, providing some definitions, history and a broad-brush starter. This led in to photointerpretation and stereoscopy, a topic seemingly missing from most geography related undergrad and postgrad programmes. It’s almost anti-tech, yet is one of those skill areas I frequently find myself revisiting. Lectures on day one finished with an introduction to low altitude platforms and some of the recent applications before we focused on KAP and then introduced the kit itself. After lunch we headed out to Zandmotor, the beach area that my colleague Paron Paron is currently using KAP to trial monitoring.

Yet again I have managed to visit the Netherlands when there is virtually no wind! There was slightly more than last time so we managed to fly the kite, but I only had my smaller Sutton Flowform so no chance in flying the camera. Next time I will bring the lightweight rig and compact camera. The morning of day 2 saw a brief introduction to photogrammetry and then a practical using both a standard vertical air photo set and a KAP photo set performing aero-triangulation in LPS.

All in all a very good two days and Delft is a very pretty location.

KAP Camera Settings

Tuesday, 20 December, 2011

Capturing aerial imagery from KAP can be a hit and miss affair (although far less so with digital cameras) and therefore setting the camera up carefully prior to imaging is essential. For oblique images there are fewer problems because there is a lot of light coming in to the camera and you can utilise whatever shutter speed/aperture you want. That’s not to say its not without problems, but that automatic camera settings can often get great shots.

When you’re trying to obtain straight verticals from KAP in order to generate DEMs (see my paper) then things become more difficult. It reminds me of a more general quote from my undergraduate days (thanks Lindsay):

"In aerial survey we have to take a large number of photographs to a set plan, from a moving platform, at a great height and at a low temperature. Alone or collectively these conditions are foreign to most photography. Despite this the photogrammetrist requires excellent definition of a low contrast object, further reduced by poor atmospheric conditions."

Which about sums things up….. OK, its not quite as severe from a kite, but the requirements for high definition photos of a low contrast object remain the same. This is even more so when we consider that we want to collect stereo imagery: the photos need to be good. So when it comes to the camera how do we actually set it up?? My paper linked above has the following paragraph in it:

"The photogrammetric use of aerial imagery requires sharp definition and this is controlled on the camera by focus, shutter speed, aperture and ISO settings. With flying heights in excess of 50m, a focus setting of infinity is used. The focus ring is normally taped and auto-focus setting switched off, this eradicates changes to the focal length during the flight. As the kite is usually moving during image capture, fast shutter speeds are needed. Field tests suggest speeds in excess of 1/500 s are required. In addition an aperture of at least F8 (for a wide angle DSLR) is preferable, to allow sufficient light to enter the camera system whilst minimizing lens distortions. In most field situations an ISO setting of at least 400 is necessary for normal UK daylight conditions. With automatic digital cameras, these stipulations mean that the ISO is set prior to image capture with the camera in 'aperture priority' mode. Prior testing may be required in order to ensure shutter speeds are fast enough."

So there we have it: tape the focal ring at infinity, put the camera in aperture priority and maintain an aperture of at least F8. The camera will auto-set the shutter speed but we actually need speeds in excess of 1/500s. This can be problematic as the only light entering the camera is reflected off the Earth’s surface and for low reflectance features (e.g. vegetation) this can be quite low. One thing I didn’t explore in the original paper was the AutoISO feature that is available on the D70 and pretty much every Nikon DSLR since. Yes, it automatically sets the ISO for you and there is a nice layman’s article here. Nikon Support also offer some sage advice. In short though, AutoISO increases the ISO speed (aka sensitivity) of the sensor in order to expose the photo correctly. The brilliant aspect when shooting in aperture priority is that you can set the threshold shutter speed at which it should kick in. So in our case we could specify 1/500s to always make sure photos are sharp.

This is no panacea though… yes it effectively adds 3 or so f-stops but you increase the noise in the image, particularly once you get over 1000. And whilst we want sharp photos for photogrammetry, noise won’t help things. Clearly some more experimentation needed here, but AutoISO is well worth enabling.

We also mustn’t forget the ambient atmospheric conditions at the time of image capture. We want sun… yes, but more than that we want texture in the image. If we are interested in enhancing topography then shadows are helpful. A low angled sun can significantly improve texture but again you lose sunlight which affects exposure. Its a careful balance which you rarely get right all the time!

P.S. And don’t forget to turn the auto-shut off to the longest possible time. You don’t want the camera to power down after 30 s!!

Netherlands KAPping

Saturday, 3 December, 2011

I’m currently involved in a project led by Paolo Paron (UNESCO-IHE) looking at beach development in the Netherlands. This is really a proof-of-concept project and follows on from the earlier training day back in October where we ran through a full kite aerial photography setup. During that day we had temperatures that peaked at 20oC…. amazing for October!

Anyway, the return trip to the Netherlands was to see the full kit that Paolo had assembled and take it to the field site for full testing/tweaking. The Netherlands is renowned for its flatness and by that I mean: bikes and wind. There were plenty of the former in evidence….. and none of the latter!!! Well, almost. It was the week of dense fog which virtually shut Amsterdam airport, however EasyJet flights in to Schiphol were almost unaffected. A remarkable effort. It was my first visit to the Netherlands and I must say, yes, it’s flat but also that the public transport system is regular, reliable and well used. Bikes are everywhere and it’s clearly a mode of transit favoured by all ages and types. Streets are wide and there are many segregated bike ways, in addition to the onus being on the driver. All in all very civilized.

Paolo (and Niels Anders, a PhD student at Amsterdam who has spent time at Kingston, and a “sixth form” student on work experience) met me at Den Haag HS railway station and from there we went out to the coast. The pictures say it all really: incredibly dense fog and winds <3 kph. Yes, that is a kite flying but t was hard enough to just get the thing off the ground let alone fly anything from it. Paolo did fully assemble the rig and camera, even though we couldn’t fly it. He has bought most of the bits from the highly recommended KAPshop and is testing one of their self-levelling rigs. He also has a Nikon D7000 which is the successor to the D70s, 80s and 90s I have used. At the moment he has a manual 20mm lens which will be interesting to see the results of the test field imagery from (in comparison to our auto-24mm).

So all in all it was disappointing not to have a full flight test, but immensely useful in fully ground testing the kit and ironing out some niggles that needed fixing in the setup. Watch this space for further results.

Back to KAP

Tuesday, 4 October, 2011

I spent a day with Paolo Paron (co-editor of our book on Geomorphological Mapping) kicking off a new kite aerial photography project. Paolo (who works at the UNESCO-IHE Institute for Water Education in Delft) is looking at monitoring morphological change at a beach in the Netherlands. KAP fits the bill so he is replicating the kit I have used for a variety of projects. Yesterday was a training day (with the UK basking in mid-summer weather!) which we spent running through the kites and ancillary equipment, then on to the rig design/setup, remote control and camera. We did three test flights just to see how it all worked. We were interested in vertical aerials, but inevitably got a few obliques (which are always more interesting to look at). Hope to have some more photography from the Netherlands in November.

Big boys UAVs: RQ-4 Global Hawk

Saturday, 16 January, 2010

A nice article over at Wired on the diversion of US military UAVs to Haiti to provide reconnaissance imagery for the relief effort. Demonstrates how the miltary are trying to get some good PR whilst also making a genuinely useful contribution. If you haven’t come across military UAVs then take a look at the RQ-4 Global Hawk; makes somewhat of a mockery of the kites I use and even some of the more security centric products. Just take a look at some of the specs:

Length: 13.54 m
Wingspan: 35.41 m
Height: 4.62 m
Gross weight: 10,387 kg
Cruise speed: 650 km/h
Endurance: 36 hours
Service ceiling: 19,812 m

It can survey up to 100,000 square kilometer of terrain a day and carries SAR VNIR instruments on board. A serious bit of kit, but then they cost $35M each. Not sure a NERC grant would stretch to one of these!

Aeryon UAV

Saturday, 8 August, 2009

The UAV market continues to develop at a pace. The Aeyron Scout as an example of a neat quadcopter design for military and security applications. It is fully programmable as well as manually controllable using a tablet PC. The camera is their own design and is specced at 5MP stills, upto 1/1000s and real-time MPEG-4 compressed video (640 x 480) all on a gimballed mount. And the amazing bit: 112g.

And the UAV part is equally interesting: 3 km range, 20 min duration, 36 kmh, 500m altitude and 1kg weight. It uses wireless modem of wifi for communication and is DGPS/WAAS capable. The comms are needed for security, but it would be interesting to know what bandwidth it needs and how much on-board storage there is. Wifi range has to be quite limited. The DGPS is an interesting option and again it would be interesting to know what chipset this is and how they intend it to be used (and, as a result, the levels of accuracy you can expect to get).

KAP Photogrammetry

Wednesday, 11 March, 2009

I was recently in touch with Ryan Strynatka, the product manager for ERDAS’ Leica Photogrammetry Suite, over my recently published paper on photogrammetry using vertical imagery from a kite. He was interested enough to write a summary which is worth a read. And, if you haven’t come across his blog, it’s worth following as he regularly updates it with all things photogrammetric.

Continuous Rotation Servos

Friday, 20 July, 2007

The rig designs I have used for flying my cameras (from kites), all use model aircraft servos (e.g. Hitec, Futaba) to drive the rotation (horizontally) of the vertically pointing camera. For photogrammetric applications, vertical photos are the only ones worth taking and therefore the vertical axis is the only one about which we need to move the camera.

This creates a problem because the servos are designed for model aircraft which require movement of up to ~90 degrees for controls such as the rudder and flaps. With rotation around the vertical axis, we ideally want continuous 360 degree rotation. So what do we do?? Well the e-magazine KAPER lists six different ways of achieving full 360 degree rotation. These employ both external modifications (gearing) and internal modifications (extra electrics). Probably the simplest, and most effective, modification is method 4 which involves opening up the servo and cutting away the bump stops and grinding off the top of the final drive gear (ideally using a Dremel).

The first rig we built uses this method, unfortunately minor fluctations in the RC transmitter means that the servo occasionally stutters or will rotate (“creep”) ever so slowly when its meant to be in a neutral position. James Gentles has produced a little bit of kit which solves this problem (and is sold at Brooxes and KAPShop). The digital Futaba RC controller I use allows micro-adjustments to the controls which actually stops creep entirely, so I didn’t need this solution.

However next on the shopping list is the Hitec HSR-1422CR which purports to allow continuous rotation out-of-the-box. It’s on order so it’ll be interesting to see if this solves the problem

Fisheye Panoramas Continued

Thursday, 19 July, 2007

Pano1Well it’s been a month since my last blog on creating panoramas from fisheye lenses. I had said I would come back to using Hugin to create panoramas, it’s just taken longer than I thought!

Hugin has a set of tabs across the top for working with the current image. Many of the tabs we don’t need to use because we are not stitching photos together. When loading a fisheye image, much of the lens information is automatically entered straight from the EXIF data. So, in summary, load your image (Assistant tab) and apply the following settings:

Assistant: set “Lens Type” to Circular Fisheye
Images: set Yaw-90, Pitch-90, Roll-0
Camera and Lens: set “Lens Type” to Circular Fisheye and “Degrees of View” to 180
Crop: you need to draw a circular mask around the part of the circular photo (i.e. exclude the black surrounding frame). If you uncheck “Always centre” then you will be able to fine tine the position of the mask
Stitcher: set “Projection” to equirectangular, “Field of View” to 360 (horizontal) and 180 (vertical), select an appropriate image size and make sure the “Stich Engine” is Nona.
Hit the “Stitch Now” Button

The original image (of Carlos!) is above and the unstitched version below. I’ll have some kite shots next week.

Pano2

Fisheye Panoramas

Saturday, 16 June, 2007

Scott Haefner had an interesting idea in combining a fisheye lens with kite aerial photography to create some 360 panoramas. Strangely Scott and I fly exactly the same cameras with a Nikon D70 and Coolpix 8400. The latter can take the Nikon fisheye lens with the aid of a converter. And it takes great pics. Scott takes a “vertical down” photo from the kite and a “vertical up” from the ground, “unstitches them” and then combines them together before putting them in to an interactive photo.

What interested me was the unstitching or unwrapping part. The lens has a 360 degree field in the vertical plane and 180 degree field of view in the horizontal plane. In essence everything in front of the camera is in the photo because it is an ultra-wide angle lens and the picture you get is a circular image (think of it as more akin to a “dome”) in the middle of a standard photo frame. OK, now point the camera straight up and take a photo. You get a picture of the sky with athe entire horizon wrapped around the outer edge of the circular picture. Now mark the centre of the photo and cut directly in to from the outside edge. Finally “unwrap” the photo, correcting for the lens distortions between the centre and edge, to produce a panoramic shot. This is essentially what the software is doing.

So what do we use to create the panoramas? Well the primary package is a command line opensource product called PanoTools. Numerous vendors have created GUI front ends (PTGui being notable), including a late beta open source product called Hugin. Whilst having a few rough edges it is really very good and works without problem for KAP purposes. PanoTools is designed for creating all sorts of panoramas, not just from fisheye lenses. In fact it models lens parameters. One important thing to note is that the lens model for the fisheye is not suitable (only 160 degrees FOV) and it is therefore necessary to get a patched DLL file (full 180 degrees FOV). A good guide (using PTGUI) can be found here. More on using Hugin in another blog.

Ultra-Light KAP Rig

Saturday, 2 December, 2006

As a result og my KAP experiences in China, I spent a while thinking about a new ultra-light camera rig. The current rig, copying Scott Haefner’s design, weighs in at over 500g with picavet cross. For conditions such as I experienced in Wuhan, its very difficult to get the rig/camera to fly, even with something like the Dopero125. I’m not prepared to reduce the quality of the camera (and the Coolpix 8400 is very good) so the next alternative was the rig.

First off, nearly all of our images are verticals; the only adjustment we need is rotation and that actually is only required through 90 degrees (to align the frame). So the new rig (right; very many thanks to Martin Abbott for the effort here) has a single-piece carbon plate picavet with a light-weight servo for rotation and the arm of the rig attached directly to the servo. Scott’s rig was very clever in that he had designed a simple gearbox to remove any stress on the servo (i.e. the rig hung off the gearbox, not the servo), but it added to the weight. The rig arm is curved to allow the camera to balance. In addition the camera can be hung at the top or bottom of the arm and, if you want, the camera can be moved to a fixed pan or tilt position. We also added a much lighter 6-channel receiver (not shown), with the whole lot coming in at a staggering 91g. We haven’t tested it yet so the concern is how the strong the servo is, however just to be on the safe side there is a safety strap so the camera doesn’t plummet to earth mid-flight! Watch this space for some more results.

Chinese KAPping

Tuesday, 22 August, 2006

I took the Dopero 125 kite out with me to Wuhan to demonstrate KAPping to our hosts at the China University of Geosciences (yes, a whole university of over 25,000 students just doing geoscience!). Summer in Wuhan is hot (33-35C) and humid, with very light wind during the day. The nights can cool down and there is often a breeze. Unfortunately our flying day was fairly typical which meant the whilst the Dopero could just get off the ground, lifting capacity was low. I was using my Coolpix 8400 (450g) which is the lightest setup I currently have and whilst the rig could get off the ground, it had the effect of dragging the kite down, pulling it vertical and then overextening it so that it lost lift and then floated to the ground. My solution was to run a long length of line out and then pull the kite into the air. This lifted the camera up quite high until it got to the point of over-extension at which point it glided down. This process just gave enough time to get some shots. This was really only a demonstrator so we weren’t photographing anything of special interest.

Stonehenge KAPping

Sunday, 16 July, 2006

I had a trip to Stonehenge today. A unique experience as normally you are not allowed within 200m of the stones, however certain groups can book to actually wander amongst the stones for a private viewing prior to opening. I was with the Young Archaeologists’ Club and had got permission to fly my kite and camera. Unusually for Salisbury Plain, there was virtually zerp wind which gave me the perfect opportunity to test my new Dopero125 from KAPShop.

For those not in the know, framed kites can fly at lower wind speeds, at steeper angles and gently sail to the ground when the wind drops. All good traits. Never having flown a Dopero before it waas a baptism by fire. Quite simply it was stupendous; the quality from Jones Airfoils was excellent and it was brilliantly stable with very good lift. My rig and camera come in at 1kg and there were no problems here. First results to the right!