Teledyne E2v Semiconductors Sas

Stéphane Gesset

Frédéric Mayer

Frédéric Barbier

Thierry Ligozat

Pierre Fereyre

Bruno Diasparra

Caroline Papaix

Gareth Powell

Christine Charrat

The invention provides a method for acquiring an image of a target code, which allows the CMOS sensor, after the reader has been triggered to acquire a target code, to rapidly determine, and internally, a desirable exposure-time value Topt for the image capture of this code. When it is triggered, the sensor activates a measuring mode Mode_MES with a rapid acquisition of image data for k different exposure-time values Ti, i=1 to k, k being at least equal to 2, and this acquisition is employed only by the sensor and to rapidly define a desirable exposure-time value on the basis of histograms H(Ti) calculated with the image data acquired with the various exposure times; this value is stored in the register of image-capture parameters, and the sensor then activates a nominal image-acquiring mode Mode_ACQ, which applies this desirable exposure-time value delivered by the registered to all the pixels of the matrix array, and the obtained image DATA-OUT is the image delivered as output by the sensor, for recognition/decoding of the code by an external system.

Method of image acquisition by an image sensor of CMOS type for the recognition of optically readable code

In an active pixel sensor comprising a photodiode Dp, a memory node MN and a readout node SN, the memory node being provided to contain the charge generated by the photodiode at the end of an integration period allowing an integration in global shutter mode and a correlated double sampling, it is envisaged to carry out, in each integration period, at least one transfer {circle around (2)} of charge from the photodiode to the memory node followed by clipping {circle around (3)} of the amount of charge contained in the memory node at an intermediate voltage tafter the start of the integration period but before a last transfer of charge {circle around (4)} to the memory node at the end of the integration period. The pixels are subsequently read out, row by row, by correlated double sampling CDS. The one or more intermediate transfers, with clipping, to the memory node during the integration period allow the dynamic range of the sensor to be extended to high levels of ambient light while retaining good sensitivity to low levels of ambient light.

Control method for an active pixel image sensor

In a sensor comprising active pixels including a photodiode PHD, a memory node MN and a read-out node SN, the memory node being provided to hold the charge generated by the photodiode at the end of an integration period enabling integration in global-shutter mode and a correlated double sampling read-out, provision is made for the charge-storage capacity of the memory node to be at least N times higher than the charge-storage capacity of the photodiode (N being an integer higher than or equal to 2) and provision is made to carry out, in each integration and read-out cycle, during the integration duration Tint(i), N transfers Tri, Tri, Triof charge from the photodiode to the memory node, the N transfers being equally distributed over the integration duration. The dynamic range of the sensor is improved under high light levels.

Method for controlling an active pixel image sensor

A circuit () for detecting the appearance of x-rays with a view to triggering a radiological image capture, comprising a set () of photodiodes that is connected to a ground (G), an amplifying circuit () and a capacitor (C), the amplifying circuit () comprising an amplifier (AMP) and a voltage source (GEN) and being connected, via a first input, to the output of the set () of photodiodes, the capacitor (C) being connected between the ground (G) and a second input of the amplifier (AMP), the detecting circuit () being characterized in that the amplifying circuit () is configured to carry out in succession the steps of:

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Saint Laurent du Pont, France

Stéphane Gesset