Image processing apparatus

• US 5,790,195 A
• Filed: 12/27/1994
• Issued: 08/04/1998
• Est. Priority Date: 12/28/1993
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Ohsawa, Hidefumi
• Primary Examiner(s): Au, Amelia
• Application Number:
  US08/363,893
• Time in Patent Office: 1,316 Days
• Field of Search: 348/614, 348/419, 348/405, 348/397, 348/400, 348/415, 348/420, 348/571, 348/607, 348/625, 382/260, 382/261, 382/262
• US Class Current: 348/419.1
• CPC Class Codes: H04N 19/80 Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation H04N19/635, H04N19/86 take precedence

Abstract

The invention provides an image processing apparatus comprising: an activity detecting unit for detecting an activity of input image data, a processing unit for space filter processing the input image data by controlling filter coefficients in accordance with the activity detected by the activity detecting unit, and an encoding unit for encoding the input image data processed by the processing unit. An image processing apparatus comprising, an activity detecting unit for detecting an activity of input image data, and a quantizing unit for quantizing the input image data by controlling a quantization step in accordance with the activity detected by the activity detecting unit is also provided.

Claims

1. An image processing apparatus comprising:

input means for inputting image data;

activity detecting means for detecting an activity of the image data input by said input means, the activity corresponding to spatial frequency content of the image data;

filtering means for performing a space filtering process on the image data input by said input means, by controlling filter coefficients in accordance with the activity detected by said activity detecting means; and

encoding means for encoding the image data processed by said filtering means.

2. An apparatus according to claim 1, wherein said space filtering process is a smoothing process.

3. An apparatus according to claim 1, further comprising motion detecting means for detecting the motion of the image data input by said input means,

and wherein said filtering means controls the filter coefficients in accordance with the activity detected by said activity detecting means and the motion detected by said motion detecting means.

4. An apparatus according to claim 3, wherein said processing means controls the filter coefficients by a fuzzy inference.

5. An apparatus according to claim 1, wherein said encoding means includes quantizing means for quantizing the input image data processed by said filtering means,

and wherein a quantization step of said quantizing means is controlled in accordance with the activity detected by said activity detecting means.

6. An apparatus according to claim 1, wherein said encoding means includes:

quantizing means for quantizing the image data processed by said filtering means;

variable-length encoding means for variable-length encoding the image data quantized by said quantizing means;

a buffer memory for once storing the image data encoded by said variable-length encoding means,

wherein a quantization step for quantizing the image data is controlled in accordance with an occupation ratio of the image data in said buffer memory.

7. An image processing apparatus according to claim 1, wherein the activity is detected by comparing a high spatial frequency component of the image data to a low spatial frequency component of the image data.

8. An image processing method comprising:

an inputting step of inputting image data;

an activity detecting step of detecting an activity of the image data input in said inputting step, the activity corresponding to spatial frequency content of the image data;

a filtering step of performing a space filtering process on the image input in said inputting step, by controlling filter coefficients in accordance with the activity detected in said activity detecting step; and

an encoding step of encoding the image data processed in said filtering step.

9. A method according to claim 8, wherein said space filtering process is a smoothing process.

10. A method according to claim 8, further comprising a motion detecting step of detecting motion of the image data input in said inputting step,

and wherein said filtering step controls the filter coefficients in accordance with the activity detected in said activity detecting step and the motion detected in said motion detecting step.

11. A method according to claim 10, wherein said processing step controls the filter coefficients by a fuzzy inference.

12. A method according to claim 8, wherein said encoding step includes a quantizing step of quantizing the input image data processed in said filtering step,

and wherein a quantization step used by said quantizing step is controlled in accordance with the activity detected in said activity detecting step.

13. A method according to claim 8, wherein said encoding step includes:

a quantizing step for quantizing the image data processed in said filtering step;

a variable-length encoding step of variable-length encoding the image data quantized in said quantizing step; and

a storage step of storing in a buffer memory the image data encoded in said variable-length encoding steps,

wherein a quantization step for quantizing of the image data is controlled in accordance with an occupation ratio of the image data in the buffer memory.

14. An image processing method according to claim 8, wherein the activity is detected by comparing a high spatial frequency component of the image data to a low spatial frequency component of the image data.