The Transverse Field Detector (TFD) is a filter-less and demosaicking-less color sensitive device that easily allows the design of more than three color acquisition channels at each pixel site. The separation of light into different wavelength bands is based on the generation of transverse electric fields inside the device depleted region, and exploits the properties of the Silicon absorption coefficient. In this work we propose such a device for the joint capture of visible and near infrared (NIR) radiation, for possible applications in videoconferencing and 3D imaging. In these applications the detector is used in combination with suitably generated NIR structured light. The information of the fourth acquisition channel, mainly capturing NIR signals, can be used both for sampling NIR light intensity and for subtracting unwanted NIR crosstalk from visible channels thus avoiding the need for the IR-blocking filter. Together with the presentation of a 4-channel sensor, a suitable algorithm for the processing of signals generated in the visible and infrared bands is described. The goal of the algorithm is to minimize the crosstalk of NIR radiation inside the visible channels and, simultaneously, to maintain good color reproduction and noise performance for the sensor, while holding a good sensitivity of the NIR channel up to 900 nm. The analysis indicates that the algorithm reduces the crosstalk of infrared signals inside R, G and B channels from 31%, 12% and 5% respectively to less than 2%. Concerning noise propagation, the worst coefficient of the color conversion matrix (CCM) is -2.1, comparable to those obtained for CCM of Bayer Color Filter Arrays.

A device and an algorithm for the separation of visible and near infrared signals in a monolithic Silicon sensor

LANGFELDER, GIACOMO;LONGONI, ANTONIO FRANCESCO;ZARAGA, FEDERICO
2011-01-01

Abstract

The Transverse Field Detector (TFD) is a filter-less and demosaicking-less color sensitive device that easily allows the design of more than three color acquisition channels at each pixel site. The separation of light into different wavelength bands is based on the generation of transverse electric fields inside the device depleted region, and exploits the properties of the Silicon absorption coefficient. In this work we propose such a device for the joint capture of visible and near infrared (NIR) radiation, for possible applications in videoconferencing and 3D imaging. In these applications the detector is used in combination with suitably generated NIR structured light. The information of the fourth acquisition channel, mainly capturing NIR signals, can be used both for sampling NIR light intensity and for subtracting unwanted NIR crosstalk from visible channels thus avoiding the need for the IR-blocking filter. Together with the presentation of a 4-channel sensor, a suitable algorithm for the processing of signals generated in the visible and infrared bands is described. The goal of the algorithm is to minimize the crosstalk of NIR radiation inside the visible channels and, simultaneously, to maintain good color reproduction and noise performance for the sensor, while holding a good sensitivity of the NIR channel up to 900 nm. The analysis indicates that the algorithm reduces the crosstalk of infrared signals inside R, G and B channels from 31%, 12% and 5% respectively to less than 2%. Concerning noise propagation, the worst coefficient of the color conversion matrix (CCM) is -2.1, comparable to those obtained for CCM of Bayer Color Filter Arrays.
SPIE Proceedings Vol. 7882
sezele
File in questo prodotto:
File Dimensione Formato  
proceeding_06_SPIE_EI11_A_device_and_an_algorithm.pdf

Accesso riservato

: Post-Print (DRAFT o Author’s Accepted Manuscript-AAM)
Dimensione 2.37 MB
Formato Adobe PDF
2.37 MB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/634649
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 12
  • ???jsp.display-item.citation.isi??? ND
social impact