About
apertus° Axiom Alpha is the name of the apertus° Axiom prototype that is more than just a proof-of-concept. It is planned to already meet the demands of real world applications like being used for film production. We are certain though that while it will not be the answer to all our prayers and not the goal of all our dreams yet it will be the first step to embark on a journey to that place where we want to be one day. The main motto with Alpha is "Keep it simple!". The features are reduced to the absolute essential core. No luxuries. So for example we chose the lens mount that is the simplest and easiest to implement from a technical point of view: The Nikon F-mount.
Current State of Development
The lens mount metal parts are done. The Field Programmable Gate Array (short FPGA) for doing the real time image processing of choice now is a recently introduced Xillinx Zynq (FPGA + dual core ARM CPU combination System on Chip [SoC]). We have ordered a Zedboard for prototyping with the Zynq, which is basically like an Arduino with incredible power. It can output a video signal via an onboard HDMI port (unfortunately there is no 3G-SDI option yet).
The Zedboard also opens up new possibilities, since its widely available for a reasonable price (much cheaper compared to the price of building custom hardware.) FPGA development is now easier to split among remotely separated developers - we can just get all of them a Zedboard. And the Zedboard has other interfaces already built in that we did not really aim for so far (Gigabit Ethernet, VGA, Audio In/Out, etc.) and the same FPGA will also be used in the final Axiom hardware, so all of the VHDL code that we create now will be reusable later on. Our next step is to create an emulated image sensor in the FPGA that acts like a real one but just generates a test pattern image for now. This is very handy for working on the image processing pipeline without having a real image-sensor front-end built yet. Other team members are working on designing the actual image-sensor front-end hardware in the meantime.
Technical Specifications
| Lens Mount | Nikon F-Mount |
| Image Sensor Size | Super 35 / APS-C |
| Resolution | 1920x1080 (downscaled from 4K Image Sensor) |
| Output | 3G-SDI (uncompressed) |
| Chroma Sampling | 4:4:4 |
| Frame Rate | 25 |
| Power Consumption | ~10W |
| Inputs/Outputs | Power In (12V DC), USB 2.0 (Camera Control), 3G-SDI Out |
F-mount prototype parts with image sensors - work in progress
F-mount prototype parts with image sensor - work in progress
Features
apertus° Axiom Alpha will utilize the same image sensor from CMOSIS that will be used in apertus° Axiom. The CMV12000 image sensor has 4K resolution and Super35 dimensions with a global shutter.
Alpha though will down-sample this resolution internally and output a clean uncompressed Full HD signal. Alpha itself will not record footage. We will not install an optical low pass
filter in front of the sensor yet and camera control will at this point only be possible with a USB 2.0 interface to send commands to the camera and receive information back.
Alpha will not record sound and will not at this point be able to record RAW. You can use any 3G-SDI recorder of choice though and most of these also have audio inputs.
By using a debayer algorithm that generates RGB values of a single pixel from a 2x2 photosite (RGBG) block we go from 4K to 2K and from bayer-pattern to 4:4:4 RGB in a single processing step
(see illustration below).
