Image processing apparatus, image processing method, noise-amount estimate apparatus, noise-amount estimate method, and storage medium

• US 6,970,605 B1
• Filed: 05/31/2000
• Issued: 11/29/2005
• Est. Priority Date: 06/01/1999
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kondo, Tetsujiro, Kobayashi, Naoki
• Primary Examiner(s): Mehta, Bhavesh M.
• Assistant Examiner(s): DESIRE, GREGORY M
• Application Number:
  US09/583,250
• Time in Patent Office: 2,008 Days
• Field of Search: 348/452, 348/535, 348/607, 348/624, 348/695, 348/533, 348/699, 358/428, 358/432, 375/240.01, 37524012-24016, 375/240.24, 382/199, 382/201, 382/232, 382/236, 382238-239, 382/251, 382/254, 382/276, 382/252
• US Class Current: 382/254
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: G06T 5/40 using histogram techniques
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: G06T 7/254 involving subtraction of images

Abstract

An image processing apparatus processes input pixel data and outputs the processed pixel data as output pixel data. The image processing apparatus includes an input reliability calculation section for calculating an input reliability indicating the reliability of the input pixel data, an output reliability calculation section for calculating an output reliability indicating the reliability of the output pixel data, a motion-amount detecting section for detecting the amount of the motion of the input pixel data, a compensation section for compensating the output reliability according to the amount of the motion, and a processing section for processing the input pixel data according to the input reliability and the compensated output reliability and for outputting the output pixel data.

Claims

1. An image processing apparatus for processing input pixel data and for outputting the processed input pixel data as output pixel data, comprising:

input reliability calculation means for calculating an input reliability indicating the reliability of the input pixel data;

output reliability calculation means for calculating an output reliability indicating the reliability of the output pixel data;

motion-amount detecting means for detecting the motion amount of the input pixel data;

compensation means for compensating the output reliability according to the motion amount; and

processing means for processing the input pixel data according to the input reliability and the compensated output reliability, and for outputting the output pixel data.

2. An image processing apparatus according to claim 1, wherein said motion-amount detecting means detects the motion amount of the input pixel data according to the difference between an image block formed of a predetermined number of pixels disposed around the input pixel data and including it, and another image block disposed at the same position as the image block on an adjacent screen.

3. An image processing apparatus according to claim 2, wherein said motion-amount detecting means extracts only pixels having the differences from the input pixel data equal to or less than a predetermined threshold when extracting pixels disposed around the input pixel data and including it.

4. An image processing apparatus according to claim 2, wherein said motion-amount detecting means detects as the motion amount the average of the differences of pixel data between an image block formed of a predetermined number of pixels disposed around the input pixel data and including it, and another image block disposed at the same position as the image block on an adjacent screen.

5. An image processing apparatus according to claim 1, further comprising noise-amount estimate means for estimating the amount of noise included in the input pixel data,

wherein said input reliability calculation means calculates the input reliability according to the noise amount.

6. An image processing apparatus according to claim 5, wherein said noise-amount estimate means comprising:

variance calculation means for calculating the variance of pixel data in a local area including the input pixel data for each input pixel data constituting one screen;

histogram generating means for generating the histogram of the variance calculated for each input pixel data; and

noise-amount calculation means for obtaining the amount of noise included in the input pixel data according to the histogram.

7. An image processing apparatus according to claim 6, wherein the noise-amount calculation means obtains the peak value of the histogram and calculates the value corresponding to the variance having the peak value as the amount of noise.

8. An image processing apparatus according to claim 1, further comprising input-pixel-data storage means for storing only a predetermined number of the input pixel data input time-sequentially.

9. An image processing apparatus according to claim 8, wherein said input reliability calculation means calculates the variance of the predetermined number of data stored by the input-pixel-data storage means, and evaluates the input pixel data currently input, according to the variance.

10. An image processing apparatus according to claim 8, wherein said input reliability calculation means calculates the average of the predetermined number of the input pixel data stored by the input-pixel-data storage means, and evaluates the input pixel data currently input, according to the error of each input pixel data against the average.

11. An image processing apparatus according to claim 8, wherein said input reliability calculation means calculates the variance and the average of the predetermined number of the input pixel data stored by the input-pixel-data storage means, obtains the error of each data against the average, and evaluates the data currently input, according the variance and the error.

12. An image processing apparatus according to claim 1, wherein said output reliability calculation means calculates the reliability of the current output pixel data according to the sum of the reliability of the input pixel data and the reliability of the output pixel data.

13. An image processing apparatus according to claim 1, further comprising output-pixel-data storage means for storing the output pixel data,

wherein said processing means adds the past output pixel data stored by the output-pixel-data storage means to the current input pixel data to obtain the output pixel data corresponding to the current input pixel data.

14. An image processing apparatus according to claim 1, further comprising weight-coefficient calculation means for obtaining a predetermined weight coefficient according to the input reliability and the output reliability,

wherein said processing means adds the current input pixel data to the output pixel data in the previous screen, corresponding to the input pixel data, with a weight according to the weight coefficient to obtain the current output pixel data.

15. An image processing method for processing input pixel data and for outputting the processed input pixel data as output pixel data, comprising:

a step of calculating an input reliability indicating the reliability of the input pixel data;

a step of calculating an output reliability indicating the reliability of the output pixel data;

a step of detecting the motion amount of the input pixel data;

a step of compensating the output reliability according to the motion amount; and

a step of processing the input pixel data according to the input reliability and the compensated output reliability, and of outputting the output pixel data.

16. A program stored on a computer-readable medium, the program for processing input pixel data and for outputting the processed input pixel data as output pixel data, the program comprising:

a step of calculating an input reliability indicating the reliability of the input pixel data;

a step of calculating an output reliability indicating the reliability of the output pixel data;

a step of detecting the motion amount of the input pixel data;

a step of compensating the output reliability according to the motion amount; and

a step of processing the input pixel data according to the input reliability and the compensated output reliability, and of outputting the output pixel data.

17. An image processing apparatus, comprising:

input reliability calculator configured to calculate an input reliability indicating the reliability of input pixel data;

output reliability calculator configured to calculate an output reliability indicating the reliability of output pixel data;

motion-amount detector configured to detect the motion amount of the input pixel data;

compensator configured to compensate the output reliability according to the motion amount; and

processor configured to process the input pixel data according to the input reliability and the compensated output reliability, and output the output pixel data.