Method for up-scaling an input image and an up-scaling system

1. A method for up-scaling an input image represented by an input video signal in an image up-scaling system, the method comprising steps of:

receiving and processing the input video signal in an up-scaling device ( 21 , 23 ), wherein the step of receiving and processing the input video signal in the up-scaling device ( 21 , 23 ) comprises steps of:

generating a first up-scaled video signal from the input video signal by up-scaling the input video signal by a rational factor of L/M, wherein L is an interpolation factor used for an interpolation of the input video signal in an interpolation element in the up-scaling device ( 21 , 23 ), and M is a decimation factor used for a decimation in a decimation element in the up-scaling device ( 21 , 23 ), and

providing the first up-scaled video signal to a signal combining device ( 24 ),

receiving and processing the input video signal in a harmonics generation device ( 22 , 25 , 26 , . . . , 30 ), wherein the step of receiving and processing the input video signal in the harmonics generating device ( 22 , 25 , 26 , . . . , 30 ) comprises steps of:

generating from the input video signal a higher harmonics video output signal representing higher harmonics of the input video signal in a frequency domain, the generating of the higher harmonics video output signal comprising steps of up-scaling the input video signal by a factor of k×(L/M) (k>1) to form a second up-scaled video signal, generating a higher harmonics video signal from the second up-scaled video signal, and decimating the higher harmonics video signal by a decimating factor of k, and

providing the higher harmonics video output signal to the signal combining device ( 24 ),

in the signal combining device ( 24 ), generating an up-scaled output image represented by an up-scaled output video signal by combing the first up-scaled video signal with the higher harmonics video output signal, and

providing the up-scaled output video signal to an output of the combining device ( 24 ).

2. Method according to claim 1 , wherein the step of generating the higher harmonics video output signal comprises a step of limiting the higher harmonics video signal in the frequency domain to frequency below a Nyquist frequency limit, wherein the step of limiting is performed by a low-pass filter element ( 28 ).

3. Method according to claim 1 , wherein the step of generating the higher harmonics video output signal comprises a step of deriving input video signal information from the input video signal by processing the input video signal.

4. Method according to claim 1 , wherein the step of up-scaling the input video signal by the factor of k×(L/M) (k>1) is performed in a diamond scaler element ( 26 ).

5. Method according to claim 1 , wherein the step of decimating the higher harmonics video signal by the decimating factor of k is performed in a decimation element ( 29 ).

6. Method according to claim 1 , wherein the step of generating the higher harmonics video output signal comprises a step of amplifying in an amplifier element ( 30 ).

7. An image up-scaling system for up-scaling an input image represented by an input video signal, the system comprising:

an up-scaling device ( 21 , 23 ), configured to:

receive and process the input video signal, and

generate a first up-scaled video signal from the input video signal,

a harmonics generation device ( 22 , 25 , 26 , . . . , 30 ), configured to:

receive and process the input signal, and

generate from the input video signal a higher harmonics video output signal representing higher harmonics of the input video signal in a frequency domain, the generating of the higher harmonics video output signal comprising steps of up-scaling the input video signal by a factor of k×(L/M) (k>1) to form a second up-scaled video signal, generating a higher harmonics video signal from the second up-scaled video signal, and decimating the higher harmonics video signal by a decimating factor of k, and

a signal combining device ( 24 ), configured to:

receive the second up-scaled video signal and the higher harmonics video output signal,

generate an up-scaled output image represented by an up-scaled output video signal by combining the first up-scaled video signal with the higher harmonics video output signal, and

provide the up-scaled output video signal to an output of the combining device ( 24 ).

8. System according to claim 7 , wherein the harmonics generation device ( 22 , 25 , 26 , . . . , 30 ) comprises a low-pass filter element ( 28 ) configured to limit the higher harmonics video signal in the frequency domain to frequency below a Nyquist frequency limit.

9. System according to claim 7 , wherein the harmonics generation device ( 22 , 25 , 26 , . . . , 30 ) comprises a high-pass filter element ( 25 ) configured to derive input video signal information from the input video signal by processing the input video signal.

10. System according to claim 7 , wherein the harmonics generation device ( 22 , 25 , 26 , . . . , 30 ) comprises a diamond scaler element ( 26 ) configured to up-scale the input video signal by the factor of k×(L/M) (k>1).

11. System according to claim 7 , wherein the harmonics generation device ( 22 , 25 , 26 , . . . , 30 ) comprises a decimation element ( 29 ) configured to decimate the higher harmonics video signal by the decimating factor of k to the higher harmonics video output signal.

12. System according to claim 7 , wherein the harmonics generation device ( 22 , 25 , 26 , . . . , 30 ) comprises an amplifier element ( 30 ) configured for signal amplification.