Apparatus, method, and computer program for processing image, and recording medium storing the computer program

Abstract

An image processing apparatus includes an image quality correction circuit for correcting an image quality of input video data by enhancing the input video data and a control circuit for controlling the image quality correction circuit. The control circuit detects a signal level of a high-frequency component of the input video data and controls the image quality correction circuit in response to the signal level detection result so that the degree of enhancement of the input video data is increased in response to an increase in the signal level of the high-frequency component.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an image processing circuit in an image pickup apparatus in accordance with a first embodiment of the present invention;

FIG. 2 is a block diagram of the image pickup apparatus of FIG. 1;

FIGS. 3A and 3B illustrate a setting process of a correction coefficient of the image processing circuit of FIG. 1;

FIG. 4 is a plot of characteristics of the correction coefficient of the image processing circuit of FIG. 1;

FIG. 5 is a plot of characteristics of the correction coefficient of the image processing circuit in accordance with a second embodiment of the present invention;

FIG. 6 is a block diagram of an image processing circuit in an image pickup apparatus in accordance with a third embodiment of the present invention;

FIG. 7 is a block diagram of a non-linear smoothing filter in the image processing circuit of FIG. 6;

FIG. 8 is a block diagram of a non-linear smoothing circuit of the non-linear smoothing filter of FIG. 7;

FIG. 9 illustrates operation of the image processing circuit of FIG. 6;

FIG. 10 is a block diagram of an image processing circuit in an image pickup apparatus in accordance with a fourth embodiment of the present invention;

FIGS. 11A and 11B are plots of characteristics representing gradation correction of the image processing circuit of FIG. 10;

FIGS. 12A and 12B are plots of characteristics representing gradation correction different from the characteristics of FIGS. 11A and 11B;

FIGS. 13A and 13B are plots of characteristics representing gradation correction different from the characteristics of FIGS. 11A and 11B and FIGS. 12A and 12B;

FIGS. 14A1-14B2 illustrate a setting process of the correction coefficient in the image processing circuit of FIG. 10; and

FIG. 15 is a block diagram of a known image processing circuit.

Claims

1. An image processing apparatus comprising: an image quality corrector for correcting an image quality of input video data by enhancing the input video data; anda controller for controlling the image quality corrector, the controller detecting a signal level of a high-frequency component of the input video data and controlling the image quality corrector in response to the signal level detection result so that the degree of enhancement of the input video data is increased in response to an increase in the signal level of the high-frequency component.

2. The information processing apparatus according to claim 1, wherein the image quality corrector enhances the high-frequency component of the input video data.

3. The information processing apparatus according to claim 2, wherein the image quality corrector comprises: an image quality correction component extractor for extracting the high-frequency component from the input video data;a level adjuster for adjusting, under the control of the controller, the signal level of the high-frequency component extracted by the image quality correction component extractor; andan adder for adding an output signal from the level adjuster to the input video data.

4. The information processing apparatus according to claim 1, wherein the image quality corrector comprises: a non-linear smoothing filter for smoothing the input video data with an edge component thereof preserved;a subtractor for subtracting an output signal output from the non-linear smoothing filter from the input video data to generate the high-frequency component; anda level detector for detecting the signal level of the high-frequency component by converting the output signal output from the subtractor into an absolute value and by summing the absolute values on a per block basis.

5. The information processing apparatus according to claim 1, wherein the controller enhances the input video data in a manner such that contrast is increased in a tonal gradation segment of the input video data having a high frequency of occurrence.

6. The information processing apparatus according to claim 5, wherein the image quality corrector comprises: a multiplier for varying, under the control of the controller, a measurement value for use in measuring the number of samples by multiplying the measurement value by an output value from the controller;a counter for detecting a histogram of the input video data by summing the measurement values, multiplied by the multiplier, on a per tonal gradation segment basis of the input video data; anda corrector for outputting the input video data with input-output characteristics of switched based on the histogram in a manner such that contrast is increased in the tonal gradation segment of the input video data having a high frequency of occurrence.

7. An image processing method comprising steps of: correcting an image quality of input video data by enhancing the input video data;detecting a signal level of a high-frequency component of the input video data; andperforming a control process in response to the signal level detection result so that the degree of enhancement of the input video data is increased in response to an increase in the signal level of the high-frequency component.

8. A computer program for causing a computer to correct image quality of input video data, comprising steps of: correcting an image quality of input video data by enhancing the input video data;detecting a signal level of a high-frequency component of the input video data; andperforming a control process in response to the signal level detection result so that the degree of enhancement of the input video data is increased in response to an increase in the signal level of the high-frequency component.

9. A recording medium storing a computer program for causing a computer to correct image quality of input video data, the computer program comprising steps of: correcting an image quality of input video data by enhancing the input video data;detecting a signal level of a high-frequency component of the input video data; andperforming a control process in response to the signal level detection result so that the degree of enhancement of the input video data is increased in response to an increase in the signal level of the high-frequency component.