Spaced Out ::

An interesting article over at Amateur Photographer which picks up an Olympus press release about the development of an RGB/NIR sensor for use in consumer grade cameras. The use of digital cameras for NIR imaging (e.g. my dead leaf photo) has been common for many years and is achieved by having a longer exposure (as the sensor is less sensitive to NIR) and placing a NIR cut filter in front of the lens (e.g. Hoya 720). Specialists such as Advanced Camera Services will even convert your camera to IR by removing the internal IR filter. Sensefly use a modified Canon S110 for the eBee UAV which can image in RGB, NIR or red edge. Which is why the Olympus announcement is interesting (for the light weight/low cost UAV sector) as I’m not aware of a major manufacturer developing a single sensor for imaging 4 bands. A traditional approach is to use a bayer array over a sensor sensitive to RGB and then interpolate (demosaic) the image to three RGB layers. Olympus appear to have extended this to 4 bands by developing realtime demosaicing to support it. The sensor is probably a standard one, albeit perhaps more sensitive to NIR. Lead time could be awhile as this is in development but it clearly shows the direction of travel.

I briefly commented on KAP cameras when looking at the PhaseOne iXU180 - a great medium format camera for medium weight UAV use. But at the lighter end of the market, for use on quadcopters, small fixed wing and kites, what to use?? The key to answering this question is what are the parameters for the camera. For me, they boil down to this:

-low weight
-wide field of view
-big sensor

Low weight is obvious - small UAVs have a relatively low lifting capacity. Wide FoV is generally good as these devices are often relatively low to the ground. And even at a drones maximum licenseable limit in the UK (~120m), that still limits what is visible. So wide is good, as long as the lens is of good quality and minimises distortions. As bigger sensor as is practicable - this maximises light capturing capabilities and so means you’ve got great latitude when flying and specifically, working at an aperture of f8 with as fast a shutter speed as possible.

So what’s around? Well, when I last looked a few years ago there was actually very little choice and somewhat surprisingly that remains the case. For a lightweight camera, fixed lenses (rather than interchangeable) are the best route to go, which means a camera designed for street photography. The limiting factor here being focal length. In terms of sensor there are options around both APS-C and full frame. So my short list currently is:

Ricoh GR2: an APS-C sensor (16MP), extremely light (250g) and a fixed focal length is equivalent to 27mm (for a full frame camera). This is ideal for aerial work. It has an intervalometer which means you can set it to take photos at regular intervals, but no IR port for remote control.

Nikon Coolpix A: also APS-C (16MP), light weight (290g) and wide angle 28mm equivalent lens (this does have an IR port but no intervalometer).

Fuji X70: very new, APS-C 16MP X-Trans sensor (not a Bayer colour filter array and so generally better colour reproduction), 28mm equivalent focal length, weighing in a 340g.

Sony RX1: 24MP full frame sensor with fixed 35mm lens. Its expensive, slightly heavier at 480g but offers significantly better optics, resolution, dynamic range and sensitivity. At a price!!

A conclusion?? Well the comparative review by DPReview finished with a great quote:

a considerable portion of its [Coolpix A] thunder is stolen by the Ricoh GR - a camera that achieves the unusual trick of being a touch better in almost every respect while also being significantly cheaper

The rapid development roadmap for DJI continues (see Phantom 3 camera review). Camera improvements continue abate and onboard you’ll find a 12MP stills camera with a 1/2.3-inch (8.8×6.6mm) sensor. ISO goes up to of 1600 for photos and, crucially, records Adobe DNG RAW. This is a BIG step forward for a drone camera as it allows much greater headroom in post processing. The field of view is 94° which is about equivalent to an 18mm lens on a full frame camera (which means wide and with lots of distortion).

What do you do when an artifact you have is in danger of loss or destruction?? Preserve it of course! And that’s the role of archivists in terms of valuable items. Preference is given for physical preservation (we want to keep to “original”) but digital preservation (not withstanding the problem of maintaining access to data) is often sought after as it allows universal access and preservation of the data used to record the “presence” of the object (sound, radiation etc). This whole topic came to fore with ISIS’s destruction of buildings in Palmyra. Whilst there has been some effort to smuggle smaller artifacts out of Syria, it’s not easy to do this for whole buildings! Which makes digital preservation paramount. Obviously there are many photos of Palmyra itself, but archivists (and archaeologists) want to take this one step further and generate 3D models and collate detailed imagery of buildings before they are destroyed.

And this is of course where photogrammetry (and more specifically Structure from Motion) comes in - by deploying a range of low cost cameras the expectation is that a large number of images can be used to create a virtual model of current buildings before they suffer destruction. The Million Image Database has probably had more publicity but New Palmyra (and backstory) is also working with similar aims and has current models hosted on Github for download. Both are light on methods so it’ll be interesting to see, technically, how these develop.

I attended the Commcerical UAV Show last month at the Excel Centre, sharing a slice of the vast area with the Robotics Show. Last year the show was upstairs at Olympia and whilst relatively small there was quite a buzz with mixing between the seminars, the conference and the trade floor. There was also a very wide range of exhibitors with some really big UAV manufacturers and smaller players, as well as software and services. Its an exciting sector and you couldnt fail to walk away not feeling the palpable excitement.

This year my overall takeaway was one of disappointment. The show seemed smaller and there were certainly fewer major operators there. That said they had a live demo area which was impressive and the stands were generally bigger with more space between them. Yuneec continued the impressive showing from the Chinese manufacturer whilst there were an innumerable number of insurance services… we can see where that one is headed! This year also saw DJI - its consumer drones becoming good enough for a range of commercial applications outside photography. There was also a surprising number of empty stalls and those which were unmanned which made for a poor impression.

Perhaps the one stand that sticks in my mind was the French manufacturer Delair-Tech. This is the first (and I believe only manufacturer) to have government approval (in France) for “beyond line of sight” (BLOS) operations. This is something that brings palpitations to any FAA executive but that Amazon (amongst others) is really pushing for. For regulated airspace this is really moving the potential for UAVs in geoscience much further.

An upcoming rival to the Commercial UAV Show is the SkyTech Event at the Business Design Centre 27-28 January 2016. This is a great space for a show so it’ll be really interesting to see what this is like. Tickets are free so no excuse not to book up!