Heptaclops camera and the 393

“Temporary diversion” that lasted for three years

Last years we were working on the multi-sensor cameras and optical parts of the cameras. It all started as a temporary diversion from the development of the model 373 cameras that we planned to use instead of our current model 353 cameras based on the discontinued Axis CPU. The problem with the 373 design was that while the prototype was assembled and successfully tested (together with two new add-on boards) I did not like the bandwidth between the FPGA and the CPU – even as I used as many connection channels between them as possible. So while the Texas Instruments DaVinci processor was a significant upgrade to the camera CPU power, the camera design did not seem to me as being able to stay current for the next 3-5 years and being able to accommodate new emerging (not yet available) sensors with increased resolution and frame rate. This is why we decided to put that design on hold being ready to start the production if our the number of our stored Axis CPU would fall dangerously low. Meanwhile wait for the better CPU/FPGA integration options to appear and focus on the development of the other parts of the system that are really important.

Now that wait for the processor is nearly over and it seems to be just in time – we still have enough stock to be able to provide NC353 cameras until the replacement will be ready. I’ll get to this later in the post, and first tell where did we get during these 3 years.
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Building and Calibrating Eyesis4π

This is a long overdue post describing our work on the Eyesis4π camera, an attempt to catch up with the developments of the last half of a year. The design of the camera started a year before that and I described the planned changes from the previous model in Eyesis4πi post. Oleg wrote about the assembly progress and since that post we did not post any updates.
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The last chance to see us at SIGGRAPH’12

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Elphel at SIGGRAPH 2012

Tuesday August 7th – Thursday August 9th

Los Angeles Convention Center, Main Hall , Booth 1058

Elphel will present Eyesis4Pi – high resolution full sphere stereophotogrammetric camera at SIGGRAPH 2012, together with it’s calibration machine. We will demonstrate full calibration process to compensate for optical aberrations, allowing to preserve full sensor resolution over the camera FOV, and distortions – for precise pixel-mapping for photogrammetry and 3D reconstruction.

All Elphel camera users are welcome, current and prospective, as well as parties interested in Eyesis4Pi. Here (booth 1058 – see plan) you can talk to the camera developers, see the calibration process and touch the actual working hardware. There is a number of passes available for exhibition only. Please contact Olga Filippova if you would like to receive one.

HomeSide 720° – A helmet mounted panoramic camera

Seeing the impressive images of the Elphel-Eyesis 4pi camera I thought it’s time to tell you about the HomeSide 720°. Like the Eyesis its purpose is to capture panorama frames with a framerate of 5fps. The major difference is that the HomeSide 720° is mounted on a helmet. To have an acceptable weight it consists of only two instead of eight Elphel 353 delivering one forth of the resolution the 4pi does. Thus the camera is able to record 30MPix frames before stitching. Additionally it’s reconfigureable to enable HDR panorama frames.

More interesting probably is the purpose it was built for. We created the assembly for indoor virtual tours. After several drawbacks we finally have an approach which works very well. We do auto leveling, auto stabilization and path extraction by image analysis only. Furthermore we recognize crossing points where the user can decide where to go when the tour is shown in the player.

This is not so easy since we neither have GPS nor IMU data. Nevertheless its possible.

All this information goes into our new webplayer which reassembles the images to a virtual tour.

Have a look at the HomeSide 720° Virtual Tour
Click into the player and use the cursor keys to navigate. You may also click and drag to change the point of view.  This tour was recorded with 10MPix i.e. one Elphel 353 with two sensors.

Important: The pi symbols shows a rendered tour, not recorded by the camera

At the moment we are improving the image quality. We are also looking for a partner to drive the development even faster to create stunning indoor virtual tours.

Introducing the River View Web Player & Other News from River Studies

It has been a long while since my last blog entry in regards to river view panoramas. In the meantime the recording setup runs basically stable (putting aside minor problems with loose connectors) even under rough conditions (see also the gallery “Making Of” at the end of this post).

I just came back from artist-in-residency stays in Varanasi/Benares and Guwahati in India, that enabled me to have a few extensive recording sessions on various vessels like house boats, motor and rowing boats on Ganges River – for one the most sacred river to Hindus and probably most worshipped river on the planet, next to being one of the most polluted rivers of the world – and Brahmaputra River in Assam.

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Subpixel Registration and Distortion Measurement

Motivation

While working on the second generation of the Eyesis panoramic cameras, we decided to try go from capturing the series of the individual panoramic images to the 3d reconstruction. There are multiple successful implementations of such process, we just plan to achieve higher precision of capturing the 3d worlds using Elphel ability to design and build the hardware specific for such purpose. While most projects are designed to work with the standard off-the-shelf cameras, we are working on building the cameras together with the devices and methods for these cameras calibration. In order to be able to precisely determine the 3-d locations of the features registered with the cameras we plan first go as far as possible to precisely map each pixel of each sub-camera (of the composite camera) image to the ray in space. That would require at least two distinctive steps:
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Live USB/CD/DVD

We made a new Live USB version of Elphel Toolkit.

It is available for downloading here.

Software

Elphel-Eyesis-4π preassembly stage

We have finally received the parts for Elphel-Eyesis-4π camera and started assembling them hoping that all will fit together as we planned. And for the most part they do, which seems a bit like magic to us: you design the camera on the computer in a 3D CAD program, make a long list of parts it will consist of and then a couple months later it all turns into physical object, not just a virtual 3D design. Of course some of the parts will need minor modifications – some are due to mistakes made by us, and some are manufacturing problems. But none of them were significant enough to prevent us from assembling the first 3 prototypes, that will be 100% operational spherical panorama cameras. Elphel-Eyesis-4π is the second generation Panoramic Imaging System by Elphel Inc. It is able to capture high-resolution images in full 360 degrees and create 4π (in steridians) spherical panoramas at a high frame rate. The actual recording device consists of a weatherproof camera head that contains the image sensor front-ends and lenses in spherical distribution to cover the entire 360 degree area. The rest of the electronic components as well as the SSDs for data storage are contained inside the camera pole. Elphel-Eyesis-4π covers a full sphere. 24 sensors (8 in horizontal array, 8 pointing at +30 to + 90 degree (zenith) and 8 pointing at -30 to -90 degree (nadir) ensure a uniform high resolution distribution over the entire covered area. A new Internal Measurement Unit (IMU) mounted at the top of the camera pole provides high resolution 3D position and orientation of the camera.

Fig.1. Test assembly.

Fig.2. 3D CAD rendering.

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NC353L-369-IMU/GPS

We are proud to add a new product and camera KIT to the Elphel portfolio. See the pricelist.

The NC353L-369-IMU/GPS is a new camera configuration with an Inertial Measurement Unit (IMU) and optional GPS receiver. In addition to storing the geographical coordinates with each captured image in a video stream this allows to also save 3D orientation (yaw, pitch and roll) and 3D acceleration (Six Degrees of Freedom Inertial Sensor) of the camera at the moment of capturing an image at very high precision (2400 samples/second). A detailed description can be found in the previous post.