Flicker correction method and device, and imaging device

• US 7,764,312 B2
• Filed: 05/11/2006
• Issued: 07/27/2010
• Est. Priority Date: 05/13/2005
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ono, Noriyuki, Nishide, Yoshiaki, Ikeyama, Hiromasa, Nakasuji, Motohiro
• Primary Examiner(s): Ye; Lin
• Assistant Examiner(s): HSU, AMY R
• Application Number:
  US11/432,078
• Publication Number:
  US 20060256208A1
• Time in Patent Office: 1,538 Days
• Field of Search: 348/227.1, 348/226.1
• US Class Current: 348/226.1
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene
• CPC Class Codes: H04N 23/745 Detection of flicker frequency or suppression of flicker wherein the flicker is caused by illumination, e.g. due to fluorescent tube illumination or pulsed LED illumination

Abstract

Even when the light intensity of the light source varies, the flicker correction can thus be made flexibly. The present invention provides a flicker correction method comprising the steps of predicting, from an image of a present flicker-corrected frame, a flicker of an image of a next frame to generate two types of flicker images having flickers different in level from each other added thereto, detecting a flicker component through comparison between the generated two types of flicker images and an image of an input next frame, generating a flicker correction value on the basis of the detected flicker component, and making flicker correction by adding the generated flicker correction value to an input image frame by frame.

Claims

1. A flicker correction method of a flicker correction device comprising the steps of:

predicting, from an image of a present flicker-corrected frame, a flicker of an image of a next frame to generate first and second types of flicker images having flickers different in level from each other added thereto;

detecting a flicker amplitude component through comparison between (a) the generated first type of flicker image and an image of an input next frame and (b) the generated second type of flicker image and the image of the input next frame;

generating a flicker amplitude correction value on the basis of the detected flicker amplitude component; and

making flicker amplitude correction by adding the generated flicker amplitude correction value to an input image frame by frame.

7. The method according to claim 1, wherein the flicker amplitude component varies in a direction in which the comparison is smaller.

8. The method according to claim 1, wherein the flicker amplitude component indicates whether an amplitude of a next frame flicker is amplified or attenuated.

2. A flicker correction device comprising:

a flicker correcting means for making flicker amplitude correction by adding a flicker amplitude correction signal to an input image signal; and

a flicker correction signal generating means for predicting a flicker of an image of a next frame from the image signal having been flicker-corrected by the flicker correcting means and an image signal not yet flicker-corrected to generate first and second types of flicker images to which flickers different in level from each other are added thereto, for detecting a flicker amplitude component through comparison between (a) the generated first type of flicker image and an image of an input next frame and (b) the generated second type of flicker image and the image of the input next frame and for generating a flicker amplitude correction value on the basis of the detected flicker amplitude component,

the flicker correcting means making flicker amplitude correction by adding the flicker amplitude correction signal generated frame by frame by the flicker correction signal generating means to the input image signal.

3. The device according to claim 2, wherein the flicker correction signal generating means comprises:

a correction phase error detecting means for detecting a correction phase error by predicting a flicker of an image signal of a next frame from the image signal flicker-corrected by the flicker correcting means and an image signal not yet flicker-corrected to generate first and second types of flicker image signals having flickers different in level to each other added thereto and making a comparison between (a) the generated first type of flicker image signals and an image signal of an input next frame and (b) the generated second type of flicker image signals and the image signal of the input next frame;

a correction amplitude error detecting means for detecting a correction amplitude error by predicting a flicker of an image signal of a next frame from the image signal flicker-corrected by the flicker correcting means and an image signal not yet flicker-corrected to generate first and second types of flicker image signals having flickers different in level to each other added thereto and making a comparison between (a) the generated first type of flicker image signals and an image signal of an input next frame and (b) the generated second type of flicker image signals and the image signal of the input next frame; and

a flicker amplitude adjusting means for generating an amplitude signal according to which the amplitude of a flicker correction signal is controlled in a direction in which the correction amplitude error detected by the correction amplitude error detecting means will be smaller,

the flicker correction signal being generated based on the correction phase error signal generated by the correction phase error detecting means and amplitude signal generated by the flicker amplitude adjusting means.

4. An image pickup device including a flicker correction device to make flicker correction by adding a flicker correction signal to an image signal captured by the image pickup device, the flicker correction device comprising:

a flicker correcting means for making flicker amplitude correction by adding a flicker amplitude correction signal to an input image signal; and

a flicker correction signal generating means for predicting a flicker of an image of a next frame from the image signal having been flicker-corrected by the flicker correcting means and an image signal not yet flicker-corrected to generate first and second types of flicker images to which flickers different in level from each other are added thereto, for detecting a flicker amplitude component through comparison between (a) the generated first type of flicker image and an image of an input next frame and (b) the generated second type of flicker image and the image of the input next frame and for generating a flicker amplitude correction value on the basis of the detected flicker amplitude component,

the flicker correcting means making flicker amplitude correction by adding the flicker amplitude correction signal generated frame by frame by the flicker correction signal generating means to the input image signal.

5. A flicker correction device comprising:

a flicker correction circuit for making flicker amplitude correction by adding a flicker amplitude correction signal to an input image signal; and

a flicker correction signal generator for predicting a flicker of an image of a next frame from the image signal having been flicker-corrected by the flicker correction circuit and an image signal not yet flicker-corrected to generate first and second types of flicker images to which flickers different in level from each other are added thereto, for detecting a flicker amplitude component through comparison between (a) the generated first type of flicker image and an image of an input next frame and (b) the generated second type of flicker image and the image of the input next frame and for generating a flicker amplitude correction value on the basis of the detected flicker amplitude component,

the flicker correction circuit making flicker amplitude correction by adding the flicker amplitude correction signal generated frame by frame by the flicker correction signal generator to the input image signal.

6. An image pickup device including a flicker correction device to make flicker correction by adding a flicker correction signal to an image signal captured by the image pickup device, the flicker correction device comprising:

a flicker correction circuit for making flicker amplitude correction by adding a flicker amplitude correction signal to an input image signal; and

a flicker correction signal generator for predicting a flicker of an image of a next frame from the image signal having been flicker-corrected by the flicker correction circuit and an image signal not yet flicker-corrected to generate first and second types of flicker images to which flickers different in level from each other are added thereto, for detecting a flicker amplitude component through comparison between (a) the generated first type of flicker image and an image of an input next frame and (b) the generated second type of flicker image and the image of the input next frame and for generating a flicker amplitude correction value on the basis of the detected flicker amplitude component,

the flicker correction circuit making flicker amplitude correction by adding the flicker amplitude correction signal generated frame by frame by the flicker correction signal generator to make flicker correction to the input image signal.