Caeleste News

Caeleste welcomed students and professors from TsingHua University

Four professors and nine students (under the leadership of prof. Feng) from Tsinghua University (THU) visited Caeleste on 21 August. We had an informal workshop on electronic design research. The TSU students presented work on high-speed SAR ADC, Delta-Sigma modula tor, millimeter-wave CMOS amplifiers and frequency synthesizer for NB-IoT application. Caeleste designers presented work on photon-to-photon image sensor operation and neuron probing.

THU is ranked as the best engineering and computer science school in the world

ELFIS first “true HDR” movie

This is a follow-up of the new sitem of April 2019 on ELFIS first true HDR image
The ELFIS imager is the first image sensor ever combining following features:

  1. True HDR or “MAF HDR”, motion artifact free HDR
  2. Global shutter using GS technology,
    • Allowing low noise CDS readout
    • Enabling Global Shutter (IWR) without dark current penalty
  3. Backside illumination
  4. TDI radiation hard design

It is developed under ESA contract 4000116089 “European Low Flux Image Sensor”, in collaboration with LFoundry (I) and Airbus (F)
Read more…

Movie: The first “true” HDR movie made with the ELFIS sensor.

This movie demonstrates HDR in combination with true global shutter: the rotating black ring “cuts through” the dark interior background as well as through the sunlit outside background. The motion blur is not affected by the local light intensity.
The two upper frames are the HG (high gain) and LG (low gain) sub-frames as recorded
The bottom frame is the resulting HDR movie.
The movie is recorded under following conditions:

  • IWR tframe=tint = 30ms thus fframe=33Hz
  • Looking through the lab’s window to sunlit buildings in the Michiel Coxystraat
  • Nikon 28mm lens, diaphragm set to 22 ( sic! this is a 15µm BSI pixel!)
  • On-chip CDS and dark frame subtraction
  • No PRNU correction, no linearization was done. Two defect rows were corrected
  • The HDR image is created by a weighted interpolation between the HG and the LG frames
  • The image is “histogram equalized” for display.

Patent US10284824 granted

Patent US10284824, filed 2017 Jan 22, was granted on 2019 May 7. It describes and protects a concept to break the data volume barrier as we encounter it in ultra-high-speed image sensors. Aggregated pixel rates nowadays exceed 10 Gigapixels/second and require a very high number of parallel electrical channels. Further increase with the present state of the art requires an even higher degree of parallelism, which soon becomes unrealistic.
Caeleste’s concept avoids the huge electrical parallelism. Data are output through an extra “photonic layer”, 3D-integrated below the image sensor IC. This layer interfaces directly with fiber optic transmission lines.
You can download the patent from here.

The patent idea was previously presented at IS Americas, from which the presentation can be found here.

Two Caeleste papers at IISW 2019

At the International Image Sensor Workshop, June 2019, Utah, USA, Caeleste will present two papers on advanced CMOS image sensors.

Peng Gao, design team leader at Caeleste will present the paper

“16.7Mpixel 8000fps sparse binarized scientific image sensor”

by Peng Gao, Sampsa Veijalainen, Jente Basteleus, Gaozhan Cai, Bert Luyssaert and Bart Dierickx

This is a large format (36.1×40.2 mm2), 4K x 4K CMOS image sensor, having single-bit binary pixels on a 8µm pitch.  By the use of a proprietary readout technique it reaches frame rates up to 8000fps in sparse mode.

 

Annotated photograph of the image sensor

Ajit Kalgi, design team leader at Caeleste, will present the paper

“Fast Charge Transfer in 100µm long PPD Pixels”

by Ajit Kumar Kalgi, Arne Crouwels, Bart Dierickx, Walter Verbruggen and Dirk Van Aken

In this paper we present a patented photodiode structure for fast charge transfer in elongated pixels. For applications requiring high frame rate and elongated pixels, charge diffusion in photodiode limits the transfer efficiency, thus ultimate frame rate. We solve this by creating electrostatic potential gradient in the elongate direction by exploiting the effect of proximity of implanted regions on the pinning voltage.

Measured diffusion time using or not using the technique.

ELFIS first true HDR image

The ELFIS imager is the first image sensor ever combining following features:

  1. True HDR (“MAF HDR”, motion artifact free HDR)
  2. Global shutter using GS technology,
    1. Allowing low noise CDS readout
    2. Enabling Global Shutter (IWR) without dark current penalty
  3. Backside illumination
  4. TDI radiation hard design

It is developed under ESA contract 4000116089 “European Low Flux Image Sensor”, in collaboration with LFoundry (I) and Airbus (F).

The first “true” HDR image of the ELFIS sensor.
Figure: The first “true” HDR image of the ELFIS sensor.

The above image is taken under following conditions

  • Looking through the lab’s window to sunlit buildings at the other side of the street
  • Nikon 55mm lens, diaphragm set to 22 (!)
  • IWR tframe=tint = 30ms
  • On-chip CDS and dark frame subtraction
  • No PRNU correction, no linearization, no bad pixel correction, no other cosmetic corrections.
  • The HDR image is created by a simple threshold at 80% of the HG saturation.
  • The image is “histogram equalized”

Read more

Caeleste in the ESA roadmap

Caeleste was since its creation involved in several long-term developments in the European Space Agency context. As an illustration find below the recent ESA presentation  “CMOS Image Sensor developments supported by the European Space Agency”, by K. Minoglou, at the 2018 EIROForum Topical Workshop.  Several Caeleste collaborations are explicitly mentioned.



Find the original slide show here.