Caeleste News

Caeleste presents image sensor with in-pixel very high linear dynamic range

From May 30 until June 2, Caeleste participated in the International Image Sensor Workshop (IISW), organized by the International Image Sensor Society. The workshop was held in Hiroshima. Caeleste presented an image sensor with an in-pixel very high linear dynamic range.

A method to increase DR using column-level automatic gain selection

Image sensors have to cope with a very high dynamic range of the captured scenes. Objects in the shadow during a noon summer day in summer, can have quite often an intensity, which is 100 000 less than the brightest parts. In night vision automotive applications, the difference can be even larger: the signal of a pedestrian behind the high beams of a car can be 10 million times less than the lights of the car or the street lights. Also in spectroscopy for medical and remote sensing, the dynamic range can be very large as the spectrum of a lamp or the sun varies greatly as a function of wavelengths. Also in stimulated emission imaging as Raman or fluorescence the signal levels can vary with several orders.
As most analog systems, image sensors have a dynamic range in the order of 60 to 80 dB.  Several methods exist to increase this dynamic range as eg the capture of a sequence of pictures with different integration times of sensitivities; these images can then be combined in software to yield a high Dynamic range image.

But for fast moving objects it is very important that the utilized method does not introduce motion induced artefacts as can be the case in the above example. In the IISW workshop Gaozhan Cai, Senior Design Engineer at Caeleste presented an image sensor with an in-pixel very high linear dynamic range (HDR) that is obtained by a unique method where in the pixel a three level transfer gate is used combined with a dual or triple gain charge storage and where a column-level automatic gain selection (AGS) is implemented. The AGS picks one out of three linear ranges each having a largely different conversion gain. The data rate remains the same as without high dynamic range, thus preserving the maximal frame rate.

For fast moving objects it is very important that the utilized method does not introduce motion induced artefacts

An example of high dynamic range image processing is shown below: The raw image (in medium gain setting) is shown over the left. Some parts of the image are clearly over illuminated while others are under illuminated. In the middle part the segmented image is shown, where the gain setting for each of the image is indicated; the rightmost image is the HDR images where the different gain images are combined and the image content compressed to fit in the display range.

How to hand-calculate MTE in frontside and backside illuminated image sensors

The spatial resolution of a camera and in general an imaging system is one of the key performance parameters apart from the temporal pixel noise. It determines which small objects can still be separated by the system. Not only the lens is limiting the spatial resolution, also the image sensor is limiting the image resolution. The macroscopic crosstalk, which is at the basis of the resolution reduction, has several components, which require complicated modeling taking into account the pixel geometry and the material properties. Prior models for this resolution or MTF prediction were based on ‘brute force’ solving the diffusion equations in a finite elements mesh detailing the pixel’s geometry.

Bart has now proposed a closed-form analytical MTF-nyquist model, being suitable for integration in a spreadsheet-like calculator, enabling thus quick surveys and design parameter trade-offs in the presence of many other image sensor parameters. The method yields an analytical expression for the Line Spread Function as intermediate result. In this way much faster system optimizations can be made.

 

Idealized pixel cross section as used in the model, and the analytical expression for the distribution of electrons as arriving at the collection photodiodes

Caeleste opnieuw bij 50 snelst groeiende techbedrijven

MADE IN MECHELEN – Voor het tweede jaar op rij hoort Caeleste bij de 50 genomineerden voor de Fast 50 Award van Deloitte. Vorig jaar won het Mechelse bedrijf nog als sterkst groeiend bedrijf uit de hardwaresector. Op 14 november worden de winnaars van 2017 bekendgemaakt.

De Deloitte Technology Fast 50 competitie is een jaarlijkse selectie van de 50 snelst groeiende en meest innovatieve technologiebedrijven met hoofdzetel in België. De Fast 50 Award wordt uitgereikt aan het snelst groeiende technologiebedrijf, waarbij de groei van het omzetpercentage van de voorbije vier jaren de doorslag geeft.

“Voor het tweede jaar op rij maken we nu deel uit van de Deloitte Technology Fast 50 Ranking. Dat is werkelijk een erkenning, maar ook een bevestiging van onze gestage en gezonde groei”, zegt Geert De Peuter, ceo van Caeleste. “Het bevestigt de wereldwijde erkenning van onze onafgebroken focus. Die ligt op het combineren van voortreffelijke technologische innovatie met klantgerichte uitmuntendheid in het uitvoeren van onze projecten.”

Sterke expertise

Caeleste specialiseert zich in de ontwikkeling en productie van CMOS beeldsensoren. Het technologiebedrijf behandelt de meest geavanceerde projecten in ruimte-, wetenschappelijke, medische, levenswetenschappelijke en industriële toepassingen. Sinds de start in 2006 heeft het Mechelse technologiebedrijf een stevige klantenportefeuille opgebouwd.

Bron: Made in Mechelen – Bart De Bruyn

Ajit Kumar Kalgi awarded at the AITA 2017

‘The Best Under 35 Paper Award’ of the AITA 2017, has been assigned to our colleague Ajit Kumar Kalgi (left) , Design Team Leader of Caeleste, for his paper ‘Multiple shutter mode radiation hard IR detector ROIC’.

The award aims at encouraging innovative studies of young researchers in the topics of interest of the AITA (International Workshop on Advanced Infrared Technology and Applications).

Caeleste hosting the launch of the (bio)medical imaging platform

To support innovations in the healthcare domain at the crossroads of the Key Enabling Technologies of biotechnology and digital technologies, DSP Valley and FlandersBio are launching 3 separate platforms: one on smart implants, one on (bio)medical imaging and one on lab-on-chip & diagnostics.

On 21/2 Caeleste was hosting the launch of the Platform on (bio)medical imaging, in Mechelen.

Caeleste is the 5th highest ranked ‘Trends Gazelle’ in Antwerp!

The Flemish weekly financial & economic magazine Trends based her selection on the growth figures of the 50 fastest growing companies in Antwerp.

Trends Gazellen is awarding competitive companies that positively influence the business environment in their region. The ‘Gazellen’ are engines of innovation, they boost employment and are often an inspiring role model.

We are proud of our Top-5 ranking which confirms Caeleste is one of those innovating leaders in our region.