Eyesis4Pi 393

Status

Available

Overview

Elphel Eyesis4Pi-26-393 is the newer generation of the full-sphere multi-camera systems for stereophotogrammetric applications. The system is calibrated to compensate for optical aberrations allowing to preserve full sensor resolution over the field of view. Distortion calibration is performed for precise pixel-mapping to automatically stitch images into panoramas, and also for photogrammetry and 3D reconstruction.   There are 24 x 5MPix sensors in the camera head, resulting in 120 MPix image acquisition. Panorama image resolution after stitching is 64 MPix, the equirectangular projection is 14000x7000. High-precision Inertial Measurement Unit IMU (ADIS 16375, 2400 samples per second) is integrated with the camera, as well as 5Hz GPS (Locosys LS20031) to provide precise position and orientation of the camera. Images, synchronized with IMU and GPS data, can be recorded to internal Solid State Drives (SSD), external swappable SSDs or to a PC over the network. Optionally Eyesis4Pi-393 camera system includes PC for image downloading and post-processing with pre-installed SDK and Free and Open Source Software for camera calibration, image acquisition and panorama stitching. Eyesis4Pi-393 can be mounted on a car for outdoor panoramic applications or carried by a person, which lets successfully create panoramas of small and narrow spaces.* Automated panoramic imagery and 3-dimensional panoramas are the 2 main applications of Eyesise4Pi-393 camera. * Car and backpack mounts are not included. Improvements over older generation Eyesis4Pi new 10393 system boards faster recording more powerful more compact - the pole is 2 times shorter lighter

Features

• 4*π (360x180) full sphere coverage
• 64 MPix panoramic image resolution after stitching
• Final panoramic image equirectangular projection dimensions - 14000x7000
• 0.05 Pix stitching precision
• Very small parallax - distance between entrance pupils: 46.5 mm
• High resolution lenses: 26x M12 lens mount
• Calibrated fixed lens to compensate for the lenses distortions
  • 10" (0.1 pix) in the center 80% x 80% area
  • 30" (0.3 pix) maximal error over the full FoV
  • <0.03um/° thermal expansion
• Precise image capture synchronization
• 5 FPS - maximum frame rate
• RAW or compressed image formats
• Images are geo-tagged - 5Hz GPS receiver (Locosys LS20031)
• High-precision IMU ADIS 16375
• Recording to:
  • internal SSDs
  • external SSDs
  • a PC over network
• Web Based GUI
• SYNC cable allows:
  • receive and log external trigger (from a sensor such as odometer or extra GNSS system)
  • generate output signal to trigger other sensors or cameras
• Weatherproof camera body and camera pole
• The Eyesis4Pi-393 system is highly customizable
• Free Software and Open Hardware

Calibration

We have developed full calibration process and post-processing software to compensate for:

• Optical aberrations, allowing to preserve full sensor resolution over the camera FoV.
• Distortions – for precise pixel-mapping for photogrammetry and 3D reconstruction.

The calibration is performed using the machine (goniometer) that rotates the camera about 2 axes by precisely known angles. To calibrate IMU one needs to match the goniometer angles with the IMU data.

Check out these articles for more details:

• Building and calibrating Eyesis4Pi
• New calibration facility

Calibration process

Calibration process drawing

3D Model

http://community.elphel.com/pictures/eyesis4pi/EYESIS4PI-26-393_resized_2.jpeg Eyesis4PI-26-393 3D

Operating

Fig.1 Cables
Fig.2 Recording to swappable external drives	Fig.3 Recording to internal SSDs or over network	Fig.4 Downloading data from internal SSDs to PC

Other info

Tech specs of a single image sensor

Model	ONSemi MT9P006
Color Image Sensor	1/2.5" bayer-pattern CMOS
Effective number of pixels	2592x1936 (5,018,112 pixels)
Aspect Ratio	Chip 4:3, Region of interest freely adjustable in 16 pixel steps
Sensor Output	12 Bit ADC
Sensor Features	Region of interest, on-chip binning and decimation
Dynamic Range	70 db (76 db at 2x2 binning)
Electronic Shutter	1 us to "very long" (~3h) in 1us steps
Shutter Type	ERS
Gain	Analog & Digital (0 db to 12 db continuous)

Head Contents Schematic

FOV of sub-cameras in Eyesis4Pi-393, color shows time of acquisition (from red to blue):1-8 horizontal sensors; 1t-8t top sensors;1b-8b bottom sensors