Elphel Eyesis4Pi

About

Elphel Eyesis4Pi is an open hardware / free software panoramic camera solution that is able to capture high-resolution - 64 MPix total (120 MPix before stitching) - 360° panoramas at a rate up to 5 frames per second at full resolution. It is the successor of the Elphel Eyesis. Images are recorded to 8 solid-state-discs (Eyesis4Pi Data Storage) which can store up to 11 hours of footage at full resolution. Meta-data like GPS-coordinates (geotags), viewing direction, movement speed, etc. are directly embedded into the images EXIF fields. Eyesis4Pi uses 24 sensor-front-ends and high-grade lenses that are triggered simultaneously with microsecond accuracy to ensure a full homogeneous spherical snapshot.

Usage Scenarios

The system was designed to be small and lightweight with a minimal distance between the entrance pupils (46.5mm) to achieve lowest possible parallax.

The primary usage scenario is to mount Eyesis4Pi on the roof of a vehicle. When driving at 50 mph (22.3 m/s) and recording at 5 FPS a full panorama is captured every 4.46 meters.

Operation & Monitoring

Eyesis is controlled from a laptop, via a web-based interface (Eyesis GUI). Which also displays real-time previews of your captured panorama footage.

Eyesis is supplied with 110V/220V AC and can be used with car power adapter (inverter), when mounted on a car roof. Power consumption is around ???W.

Models

4π (or 4Pi) corresponds to a full full spherical (360°x180°) field of view in steradians.

There are 2 version of the camera Eyesis4Pi with 24 image sensors and full sperical field of view and Eyesis3Pi with 16 sensors (without 8 bottom modules) with slightly smaller field of view.

Comparison between Eyesis and Eyesis4Pi

Parameter	Eyesis	Eyesis4Pi (Eyesis 3Pi without 8 bottom modules)	Notes
Combined field of view (steradians)	3*π	4*π (3*π)
Number of image sensors	9	24 (16)
Angular resolution +/-30° from the horizon	≥4.2Mpix/steradian	≥4.2Mpix/steradian	1
Angular resolution +30° to +90°(zenith)	≥0.83Mpix/steradian	≥4.2Mpix/steradian	1
Angular resolution -30° to -90°(nadir)	none	≥4.2Mpix/steradian (none)	1
Combined megapixels	45.0	120.0 (80.0)
Combined megapixels (w/o overlapping areas)	34.0	64.0 (48.0)
Combined megapixels (w/o overlapping areas, worst case resolution)	29.0	52.8 (39.6)	1,2
Distance between entrance pupils of adjacent horizontal lenses	34.5mm	46.5mm
Distance between entrance pupils of horizontal and top/bottom lenses	75mm	50mm	3
Maximal frame rate	5fps	5fps	4
Maximal recording data rate	48MB/s	128MB/s (96Mb/s)
Maximal direct network data rate	30MB/s	80MB/s (60MB/s)
GPS receiver	external, USB	External/internal, USB/RS232
GPS pulse-per-second input	no	yes
IMU	none	ADIS163xx,ADIS164xx
Data unload	removable SSD in cradles	eSATAx2
Storage devices type	2.5″ SSD	1.8″SSD
Number of storage devices	3	8 (6)

Notes:

1. Angular resolution per pixel differs in the sub-camera FOV, minimal resolution is used.
   
2. Zenith area for Eyesis (covered by fisheye lens) is calculated separately.
   
3. For Eyesis the distance is measured from the entrance pupil of the horizontal lens to that of the top fisheye, for Eysis-4pi – to the entrance pupil of the lens immediately above/below the first one.
   
4. Frame rate may be limited by the recording (or network if the SSD are not used) datarate for high compression quality (>0.3 bytes/pixel), required for the aberration correction.