METHOD FOR READING A TWO-DIMENSIONAL MATRIX OF PIXELS AND DEVICE FOR IMPLEMENTING SUCH A METHOD

• US 20090115877A1
• Filed: 10/14/2008
• Published: 05/07/2009
• Est. Priority Date: 11/05/2007
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Original Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Inventors: VERDANT, Arnaud
• Granted Patent: US 8,284,281 B2
• Time in Patent Office: Days
• US Class Current: 348/302
• CPC Class Codes: H04N 25/445 by skipping some contiguous pixels within the read portion of the array
• CPC Class Codes: H04N 25/671 for non-uniformity detection or correction
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

The invention relates to a method for reading a two-dimensional matrix (12) of pixels of an image sensor, said matrix being organized in blocks of pixels (16) forming macropixels, each macropixel being readable independently of one another in high resolution mode and/or in low resolution mode.

According to the invention, this method comprises the steps consisting:

• • during the selection (at 50) of the high resolution readout mode for a macropixel, in reading (at 58) and storing (at 60) the values of the pixels thereof, in order to define a reference macropixel;
  • during the subsequent high resolution readout cycles of this macropixel (at 62), in forming (at 66) the difference between the read values of the pixels thereof and the values of the corresponding pixels of the reference macropixel.

Claims

1. A method for reading a two-dimensional matrix of pixels of an image sensor, said matrix being organized in blocks of pixels forming macropixels, each macropixel being readable independently of one another in high resolution mode and/or low resolution mode, wherein it comprises the steps consisting:

during the selection of the high resolution readout mode for a macropixel, in reading and storing the values of the pixels thereof, in order to define a reference macropixel;

during the subsequent high resolution readout cycles of this macropixel, in forming the difference between the read values of the pixels thereof and the values of the corresponding pixels of the reference macropixel.

2. The method for reading a two-dimensional matrix of pixels of an image sensor as claimed in claim 1, wherein the matrix is readout by default in low resolution mode, the selection and deselection of the high resolution readout mode for a given macropixel being a function of the detection or not of a movement in or in the neighborhood of this macropixel.

3. The method for reading a two-dimensional matrix of pixels of an image sensor as claimed in claim 1, wherein the high resolution readout mode of a macropixel is selected when a movement is detected therein or in a neighboring macropixel and deselected when no movement is any longer detected therein or in a neighboring macropixel.

4. The method for reading a two-dimensional matrix of pixels of an image sensor as claimed in claim 1, wherein a movement is detected in a given macropixel when the values recorded in two successive readouts of this macropixel in low resolution mode display a variation greater than a predefined threshold.

5. A device for reading a two-dimensional matrix of pixels of an image sensor, said matrix being organized in blocks of pixels forming macropixels, the device comprising means for reading each macropixel independently of one another in high resolution mode and/or in low resolution mode, wherein it comprises:

means for storing the values of the pixels of a macropixel when the high resolution readout mode is selected for it, in order to define a reference macropixel; and

means for fonming the difference between the read values of the pixels of this macropixel and the values of the corresponding pixels of the reference macropixel.

6. A device for reading a two-dimensional matrix of pixels of an image sensor as claimed in claim 5, wherein it further comprises means for selecting or deselecting the high resolution readout mode for a given macropixel according to the detection or not of a movement in or in the neighborhood of this macropixel.

7. A device for reading a two-dimensional matrix of pixels of an image sensor as claimed in claim 5, wherein the means for storing and forming the difference are produced in analog form.

8. A device for reading a two-dimensional matrix of pixels of an image sensor as claimed in claim 7, wherein it comprises means for analog-to-digital conversion of the difference formed.

9. A device for reading a two-dimensional matrix of pixels of an image sensor as claimed in claim 5, wherein it comprises means for analog-to-digital conversion of the values read for a pixel or a macropixel.

10. A device for reading a two-dimensional matrix of pixels of an image sensor as claimed in claim 9, wherein said means for storing the values of the pixels of a macropixel are a digital memory, and in that said means for forming the difference consist of a digital circuit.