Fixed pattern noise removal circuit, fixed pattern noise removal method, program, and image pickup apparatus

• US 20080239110A1
• Filed: 03/17/2008
• Published: 10/02/2008
• Est. Priority Date: 03/28/2007
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Hara, Manabu
• Granted Patent: US 8,089,533 B2
• Time in Patent Office: Days
• US Class Current: 348/241
• 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

A fixed pattern noise removal circuit is provided for removing vertical streak fixed pattern noise from an output signal of an image sensor including an output system for every predetermined number of columns. The fixed pattern noise removal circuit includes a correction signal output unit configured to output a correction signal corresponding to the output system in accordance with an offset component and a light-intensity-dependent component of the fixed pattern noise occurring in the output system, and a signal correction unit configured to remove the fixed pattern noise from the output signal of the image sensor on the basis of the correction signal output from the correction signal output unit.

Claims

1. A fixed pattern noise removal circuit for removing vertical streak fixed pattern noise from an output signal of an image sensor including an output system for every predetermined number of columns, comprising:

a correction signal output unit configured to output a correction signal corresponding to the output system in accordance with an offset component and a light-intensity-dependent component of the fixed pattern noise occurring in the output system; and

a signal correction unit configured to remove the fixed pattern noise from the output signal of the image sensor on the basis of the correction signal output from the correction signal output unit.

2. The fixed pattern noise removal circuit according to claim 1, wherein the correction signal output unit outputs a first correction signal corresponding to the offset component and a second correction signal corresponding to the light-intensity-dependent component, and wherein the signal correction unit includes a subtracter configured to subtract a black level from the output signal of the image sensor, a first adder configured to add the first correction signal to an output signal of the subtracter, a multiplier configured to multiply an output signal of the first adder by the second correction signal, and a second adder configured to add the black level to an output signal of the multiplier.

3. The fixed pattern noise removal circuit according to claim 1, wherein the correction signal output unit outputs a first correction signal corresponding to the light-intensity-dependent component and a second correction signal corresponding to the offset component and the light-intensity-dependent component, and wherein the signal correction unit includes a subtracter configured to subtract a black level from the output signal of the image sensor, a multiplier configured to multiply an output signal of the substacter by the first correction signal, a first adder configured to add the second correction signal to an output signal of the multiplier, and a second adder configured to add the black level to an output signal of the first adder.

4. The fixed pattern noise removal circuit according to claim 1, wherein the correction signal output unit includes a memory configured to store the correction signals corresponding to the output systems and a memory control unit configured to read out, from the memory, the correction signal corresponding to the output system that outputs an output signal of the image sensor on the basis of a synchronization signal that is synchronized with the output signal of the image sensor.

5. The fixed pattern noise removal circuit according to claim 1, wherein the correction signal output unit includes a plurality of registers configured to output the correction signals corresponding to the output systems, a selector configured to selectively retrieve a predetermined correction signal from among the correction signals output from the registers, a memory configured to store an output selection signal corresponding to each of the output systems, and a memory control unit configured to read out, from the memory, an output selection signal corresponding to the output system that outputs an output signal of the image sensor on the basis of the synchronization signal that is synchronized with the output signal of the image sensor, and wherein the selector selectively retrieves the predetermined correction signal from among the correction signals output from the registers on the basis of the output selection signal read out from the memory.

6. The fixed pattern noise removal circuit according to claim 1, wherein the correction signal output unit includes a plurality of registers configured to output the correction signals corresponding to the output systems, a selector configured to selectively retrieve a predetermined correction signal from among the correction signals output from the registers, and a counter configured to perform a counting operation on the basis of a synchronization signal that is synchronized with the output signal of the image sensor, and wherein the selector selectively retrieves the predetermined correction signal from among the correction signals output from the registers on the basis of a count value in the counter.

7. The fixed pattern noise removal circuit according to claim 1, further comprising:

a correction coefficient output unit configured to output a correction coefficient for correcting the gain of the correction signal and a gain correction unit configured to multiply the correction signal output from the correction signal output unit by the correction coefficient output from the correction coefficient output unit.

8. The fixed pattern noise removal circuit according to claim 7, wherein the correction coefficient output unit outputs the correction coefficient corresponding to the output system that outputs the output signal of the image sensor.

9. The fixed pattern noise removal circuit according to claim 8, wherein the correction coefficient output unit includes a memory configured to store the correction coefficient corresponding to each of the output systems, and a memory control unit configured to read out, from the memory, the correction coefficient corresponding to the output system that outputs an output signal of the image sensor on the basis of a synchronization signal that is synchronized with the output signal of the image sensor.

10. The fixed pattern noise removal circuit according to claim 8, wherein the correction coefficient output unit includes a plurality of registers configured to output the correction coefficients corresponding to the output systems, a selector configured to selectively retrieve a predetermined correction coefficient from among the correction coefficients output from the registers, a memory configured to store an output selection signal corresponding to each of the output systems, and a memory control unit configured to read out, from the memory, the output selection signal corresponding to the output system that outputs an output signal of the image sensor on the basis of a synchronization signal that is synchronized with the output signal of the image sensor, and wherein the selector selectively retrieves the predetermined correction coefficient from among the correction coefficients output from the registers on the basis of the selection signal read out from the memory.

11. A fixed pattern noise removal method for removing vertical streak fixed pattern noise from an output signal of an image sensor including an output system for a predetermined number of columns, comprising the steps of:

acquiring a correction signal corresponding to the output system in accordance with an offset component and a light-intensity-dependent component of the fixed pattern noise occurring in the output system; and

removing the fixed pattern noise from the output signal of the image sensor on the basis of the correction signal retrieved in the step of acquiring a correction signal corresponding to the output system.

12. A computer program product comprising:

a computer-readable program for, in order to remove vertical streak fixed pattern noise from an output signal of an image sensor including an output system for every predetermined number of columns, causing a computer to function as correction signal output means for outputting a correction signal corresponding to the output system in accordance with an offset component and a light-intensity-dependent component of the fixed pattern noise occurring in the output system, and function as signal correction means for removing the fixed pattern noise from the output signal of the image sensor on the basis of the correction signal output from the correction signal output means.

13. An image pickup apparatus comprising:

an image sensor including an output system for every predetermined number of columns; and

a fixed pattern noise removal circuit for removing vertical streak fixed pattern noise from an output signal of the image sensor;

wherein the fixed pattern noise removal circuit includes a correction signal output unit configured to output a correction signal corresponding to the output system in accordance with an offset component and a light-intensity-dependent component of the fixed pattern noise occurring in the output system and a signal correction unit configured to remove the fixed pattern noise from the output signal of the image sensor on the basis of the correction signal output from the correction signal output unit.