Teledyne E2v Semiconductors Sas

Gareth Powell

Thierry Ligozat

Bruno Diasparra

Stéphane Gesset

Romain Guiguet

Arnaud Foucher

Jérôme Vanrumbeke

A CMOS image sensor for a code reader in an optical code recognition system incorporates a digital processing circuit that applies a calculation process to the capture image data as said data acquired by the sequential readout circuit of the sensor, in order to calculate a macro-image from the capture image data, which corresponds to location information of code(s) in the capture image, and transmit this macro-image in the image frame following the capture image data, in the footer of the frame.

Image sensor for optical code recognition

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

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St. Martin d'Uriage, France

Gareth Powell