SIGNAL PROCESSING DEVICE AND CONTROL PROGRAM

• US 20120314968A1
• Filed: 11/08/2010
• Published: 12/13/2012
• Est. Priority Date: 02/15/2010
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Gohshi, Seiichi
• Granted Patent: US 8,891,898 B2
• Time in Patent Office: Days
• US Class Current: 382/263
• CPC Class Codes: G06T 2207/20201 Motion blur correction
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: H04N 5/142 Edging; Contouring
• CPC Class Codes: H04N 5/208 for compensating for attenuation of high frequency components, e.g. crispening, aperture distortion correction

Abstract

A signal processing device (500a) subjects a signal indicative of a moving image constituted by frames to a sharpening process for the moving image, to output a signal indicative of the sharpened moving image, and includes: a motion detection section (200) for detecting motion between the frames with respect to each block region consisting of one or a plurality of adjacent pixels constituting each frame; a sharpening process section (100) for subjecting a signal indicative of an image of a block region from which motion has been detected to a nonlinear process by a nonlinear process section (102) and sharpening the signal to generate a harmonic; and a signal output section (300) for outputting, with respect to the block region from which motion has been detected, the harmonic produced by sharpening a signal indicative of a moving image of the block region, while outputting, with respect to a block region from which motion has not been detected, a signal indicative of a moving image of the block region.

Claims

1. A signal processing device that subjects a signal indicative of a moving image constituted by a plurality of temporarily consecutive frames to a sharpening process for the moving image, to output a signal indicative of a moving image thus sharpened,

the signal processing device comprising:

motion detection means for detecting motion between the frames with respect to each block region consisting of one or a plurality of adjacent pixels constituting each of the frames;

first high-frequency component generation means for generating a harmonic having been produced by sharpening a signal indicative of a moving image of the block region from which the motion has been detected by the motion detection means; and

signal output means for outputting, with respect to the block region from which the motion has been detected by the motion detection means, the harmonic having been produced by sharpening a motion region signal that is a signal indicative of a moving image of the block region, while outputting, with respect to the block region from which the motion has not been detected by the motion detection means, a non-motion region signal that is a signal indicative of a moving image of the block region,

the first high-frequency component generation means including;

first low-frequency component removing means for removing, from frequency components of the motion region signal, at least a direct current component, to generate and output a first low-frequency-free signal;

first nonlinear process means for receiving the first low-frequency-free signal, generating a first nonlinear process signal (i) in which positive and negative signs of the first low-frequency-free signal are retained and (ii) which broadly monotonically increases nonlinearly with respect to the first low-frequency-free signal when values of the first low-frequency-free signal are at least in the vicinity of 0, and outputting the first nonlinear process signal; and

addition means for adding the first nonlinear process signal to the motion region signal, to generate the harmonic.

4. The signal processing device as set forth in claim 1, further comprising:

fourth high-frequency component generation means for sharpening, before the non-motion region signal is outputted from the signal output means, the non-motion region signal,

the fourth high-frequency component generation means including;

fourth low-frequency component removing means for removing, from frequency components of the non-motion region signal, at least a direct current component, to generate and output a fourth low-frequency-free signal;

fourth nonlinear process means for receiving the fourth low-frequency-free signal, generating a fourth nonlinear process signal (i) in which positive and negative signs of the fourth low-frequency-free signal are retained and (ii) which broadly monotonically increases nonlinearly with respect to the fourth low-frequency-free signal when values of the fourth low-frequency-free signal are at least in the vicinity of 0, and outputting the fourth nonlinear process signal; and

fourth addition means for adding the fourth nonlinear process signal to the non-motion region signal, to sharpen the non-motion region signal.

5. The signal processing device as set forth in claim 1, wherein

at least one of the first nonlinear process means, the second nonlinear process means, the third nonlinear process means, and the fourth nonlinear process means includes:

even exponentiation operation means for generating an even exponentiation signal by raising an incoming signal to an even exponent not less than 2; and

sign changing means for reversing positive and negative signs of a part of the even exponentiation signal which part is different in sign from the incoming signal, and

the even exponentiation signal including the signs having been reversed by the sign changing means is outputted.

6. The signal processing device as set forth in claim 1, wherein

at least one of the first nonlinear process means, the second nonlinear process means, the third nonlinear process means, and the fourth nonlinear process means includes:

even exponentiation operation means for generating an even exponentiation signal by raising an incoming signal to an even exponent not less than 2;

differentiation means for generating a differential signal by differentiating the even exponentiation signal; and

sign changing means for reversing positive and negative signs of a part of the differential signal which part is different in sign from the incoming signal, and

the differential signal including the signs having been reversed by the sign changing means is outputted.

7. The signal processing device as set forth in claim 1, wherein

at least one of the first nonlinear process means, the second nonlinear process means, the third nonlinear process means, and the fourth nonlinear process means includes:

odd exponentiation operation means for raising an incoming signal to an odd exponent not less than 3, and

a resulting signal obtained by raising by the odd exponentiation operation means is outputted.

8. The signal processing device as set forth in claim 1, wherein

at least one of the first nonlinear process means, the second nonlinear process means, the third nonlinear process means, and the fourth nonlinear process means includes:

square root operation means for generating a square root signal by multiplying (i) a square root of an absolute value of a value calculated by dividing an incoming signal by a possible maximum value of the incoming signal, by (ii) the maximum value; and

sign changing means for reversing positive and negative signs of a part of the square root signal which part is different in sign from the incoming signal, and

the square root signal including the signs having been reversed by the sign changing means is outputted.

9. The signal processing device as set forth in claim 1, wherein

at least one of the first nonlinear process means, the second nonlinear process means, the third nonlinear process means, and the fourth nonlinear process means, when values of an incoming signal are around 0, outputs a signal having an absolute value larger than that of the incoming signal.

10. The signal processing device as set forth in claim 1, wherein

at least one of the first low-frequency component removing means, the second low-frequency component removing means, the third low-frequency component removing means, and the fourth low-frequency component removing means is a high-pass filter having 3 or more taps.

11. The signal processing device as set forth in claim 1, wherein

at least one of the first low-frequency component removing means, the second low-frequency component removing means, the third low-frequency component removing means, and the fourth low-frequency component removing means further includes:

low-level signal removing means for changing, out of signal values of an outgoing signal, signal values whose absolute values are lower than a predetermined lower limit to 0, and

high-level signal removing means for changing, out of the signal values of the outgoing signal, signal values whose absolute values are higher than a predetermined upper limit in such a manner that the absolute values are not higher than the predetermined upper limit while maintaining signs of that signal values.

12. The signal processing device as set forth in claim 11, wherein

at least one of the first nonlinear process means, the second nonlinear process means, and the third nonlinear process means further includes:

first amplitude adjustment means for adjusting an amplitude of the outgoing signal by multiplying the amplitude by a first predetermined magnification value.

13. The signal processing device as set forth in claim 12, wherein

the first amplitude adjustment means sets the first predetermined magnification value according to a size of motion having been detected by the motion detection means.

14. The signal processing device as set forth in claim 13, wherein

the fourth nonlinear process means further includes:

fourth amplitude adjustment means for adjusting an amplitude of the fourth nonlinear process signal by multiplying the amplitude by a second predetermined magnification value, and

the first predetermined magnification value is larger than the second predetermined magnification value.

15. The signal processing device as set forth in claim 1, wherein

the motion detection means includes:

difference calculation means for calculating a difference signal indicative of a difference between adjacent two frames;

first high frequency component calculation means for calculating, with respect to said each block region, a first high frequency component included in one of the two frames;

second high frequency component calculation means for calculating, with respect to said each block region, a second high frequency component included in the other of the two frames;

third high frequency component calculation means for calculating, with respect to said each block region, a third high frequency component by adding a product of the first high frequency component and a first coefficient to a product of the second high frequency component and a second coefficient; and

division means for calculating, with respect to said each block region, a motion signal by dividing the difference signal by the third high frequency component,

motion being detected when the motion signal in said each block region is larger than a predetermined threshold.

20. A control program for causing a computer in a signal processing device as set forth in claim 1 to operate as the means of the signal processing device.

2. A signal processing device that subjects a signal indicative of a moving image constituted by a plurality of temporarily consecutive frames to a sharpening process for the moving image, to output a signal indicative of a moving image thus sharpened,

the signal processing device comprising:

motion detection means for detecting motion between the frames with respect to each block region consisting of one or a plurality of adjacent pixels constituting each of the frames;

first high-frequency component generation means for generating a first sharpening signal by sharpening a signal indicative of a pixel group consisting of pixels positioned adjacently in a main scanning direction of a moving image of the block region from which the motion has been detected by the motion detection means;

second high-frequency component generation means for generating a second sharpening signal by sharpening a signal indicative of a pixel group consisting of pixels positioned adjacently in a sub-scanning direction of the moving image represented by the first sharpening signal; and

signal output means for outputting, with respect to the block region from which the motion has been detected by the motion detection means, the second sharpening signal having been produced by sharpening a motion region signal that is a signal indicative of a moving image of the block region, while outputting, with respect to the block region from which the motion has not been detected by the motion detection means, a non-motion region signal that is a signal indicative of a moving image of the block region,

the first high-frequency component generation means including;

first low-frequency component removing means for removing, from frequency components of a main scanning direction signal that is a signal indicative of a pixel group consisting of pixels positioned adjacently in a main scanning direction of a moving image of the block region from which the motion has been detected by the motion detection means, at least a direct current component, to generate and output a first low-frequency-free signal;

first nonlinear process means for generating a first nonlinear process signal (i) in which positive and negative signs of the first low-frequency-free signal are retained and (ii) which broadly monotonically increases nonlinearly with respect to the first low-frequency-free signal when values of the first low-frequency-free signal are at least in the vicinity of 0; and

first addition means for adding the first nonlinear process signal to the main scanning direction signal, to generate the first sharpening signal,

the second high-frequency component generation means including;

second low-frequency component removing means for removing, from frequency components of a sub-scanning direction signal that is a signal indicative of a pixel group consisting of pixels positioned adjacently in a sub-scanning direction of a moving image represented by the first sharpening signal, at least a direct current component, to generate a second low-frequency-free signal;

second nonlinear process means for generating and outputting a second nonlinear process signal (i) in which positive and negative signs of the second low-frequency-free signal are retained and (ii) which broadly monotonically increases nonlinearly with respect to the second low-frequency-free signal when values of the second low-frequency-free signal are at least in the vicinity of 0; and

second addition means for adding the second nonlinear process signal to the sub-scanning direction signal, to generate the second sharpening signal.

3. The signal processing device as set forth in claim 2, further comprising:

third high-frequency component generation means for sharpening, before the second sharpening signal is outputted from the signal output means, a temporal direction signal that is a signal indicative of a pixel group consisting of pixels positioned adjacently in a temporal direction of a moving image represented by the second sharpening signal,

the third high-frequency component generation means including;

third low-frequency component removing means for removing, from frequency components of the temporal direction signal, at least a direct current component, to generate and output a third low-frequency-free signal;

third nonlinear process means for generating a third nonlinear process signal (i) in which positive and negative signs of the third low-frequency-free signal are retained and (ii) which broadly monotonically increases nonlinearly with respect to the third low-frequency-free signal when values of the third low-frequency-free signal are at least in the vicinity of 0; and

third addition means for adding the third nonlinear process signal to the temporal direction signal, to sharpen the temporal direction signal.

16-19. -19. (canceled)

21. (canceled)