July 27, 2013

NC393 development progress – 2

by Andrey Filippov

10385 - Power Supply Board layout

10385 – Power supply board layout

There is a small update to the previous post – circuit design and the PCB layout is done for the two companion boards. And it lead to some re-design on the system board. When working on the power supply board (it provides camera with the regulated 3.3V from the external source) I realized that it will have to hang on just two screws – not good for a rather heavy board with Traco DC/DC module (same size as the one currently used in Elphel NC353L camera). The 10393 system board and the 10389 Interface/SSD boards will be mounted on two sides of the aluminum heat sink plate (CNC-ed to match component heights) and the smaller 10385 will sit on top of the 10393, and all the 10385 mount screws have to go through the system board. So I had to add additional holes near the middle of the 10393. That in turn required to move the 40-pin inter-board connector that carries SATA, USB, synchronization and additional general purpose signals to the 10389. So I had to re-route part of the design, but it was a right time to do as none of the boards was released yet leaving the freedom for such modifications. These new holes will also improve the mounting of the heat sink to the Zynq chip (the large white square on the 10393 layout below).

July 13, 2013

NC393 development progress

by Andrey Filippov

Development of the NC393 is now started, at last – last 6 weeks I’m working on it full time. It is still a long way ahead before the new camera will replace our current model 353, but at least the very first step is completed – I just finished the PCB layout of the system board.

10353 System Board PCB layout

10393 System Board PCB layout

There were not so many changes to the specs/features that were planned and described in the October 2012 post, the camera will be powered by Xilinx Zynq SoC (XC7Z030-1FBG484C to be exact) that combines high performance FPGA with a dual ARM CPU and generous set of built-in peripherals. It will have 1GB of on-board system memory and 512MB of additional dedicated video/FPGA memory  (the NC353 has 64MB each of them). Both types of memory consist of the same 256Mx16 DDR3 chips – 2 for the system (to use full available memory bus width of 32 bits) and one for the FPGA.

The main class of the camera applications remains to be a multi-sensor. Even more so – the smallest package of the Zynq 7030 device turned out to have sufficient number of I/Os to accommodate 4 sensor ports – originally I planned only 3 of them. These sensor ports are fully compatible with our current 5MPix sensor boards and with the existent 10359 sensor multiplexer boards – with such multiplexers it will be possible to control up to 12 sensors with a single 10393. Four of the connectors are placed in two pairs on both sides of the PCB, so they overlap on the layout image.


June 5, 2013

Elphel new camera calibration facility

by Andrey Filippov

Fig.1. Elphel new calibration pattern

Elphel has moved to a new calibration facility in May 2013. The new office is designed with the calibration room being it’s  most important space, expandable when needed to the size of  the whole office with the use of wide garage door.  Back wall in the new calibration room is covered with the large, 7m x 3m  pattern, illuminated with bright fluorescent lights.  The length of the room allows to position the calibration machine 7.5  meters away from the pattern. The long space and large pattern will allow to calibrate Eyesis4π positioned far enough from the pattern to be withing depth of field of its lenses focused for infinity, while still keeping wide angular size, preferred for accuracy of measurements.

We already hit the precision limits using the previous, smaller pattern 2.7m x 3.0m. While the software was designed to accommodate for the pattern where each of the nodes had to have individually corrected position (from the flat uniform grid), the process assumed that the 3d coordinates of the nodes do not change between measurements.

October 25, 2012

Heptaclops camera and the 393

by Andrey Filippov

“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.

September 24, 2012

Building and Calibrating Eyesis4π

by Andrey Filippov

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.

August 9, 2012

The last chance to see us at SIGGRAPH’12

by Oleg Dzhimiev

Thanks to everyone who had visited us, learned about Eyesis4Pi and suggested some new applications. We hope you have enjoyed our discussions as much as we did.
We are glad to see so much interest in the Eyesis4π panoramic applications we have demonstrated and we continue to look for collaboration in 3D reconstruction based on our camera calibrated for photogrammetry.


July 19, 2012

Elphel at SIGGRAPH 2012

by Olga Filippova

We are glad to meet you at SIGGRAPH 2012, Booth 1058

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.

February 22, 2012

HomeSide 720° – A helmet mounted panoramic camera

by Andreas Bean

Homeside 720°

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.

February 10, 2012

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

by Michael Aschauer

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.


October 31, 2011

Subpixel Registration and Distortion Measurement

by Andrey Filippov


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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