Apparatus for digitally filtering a video signal, and related method

• US 7,978,268 B2
• Filed: 08/25/2006
• Issued: 07/12/2011
• Est. Priority Date: 08/26/2005
• Status: Active Grant

• Current Assignee: Realtek Semiconductor Corp.
• Original Assignee: Realtek Semiconductor Corp.
• Inventors: Kung, Wen-Hsia, Chen, Szu-Ping, Li, Kuo-Yang
• Primary Examiner(s): KOSTAK, VICTOR R
• Application Number:
  US11/467,163
• Publication Number:
  US 20070046824A1
• Time in Patent Office: 1,782 Days
• Field of Search: 348/606, 348/607, 348/625, 348/241, 348/248, 348/452, 382260-266, 358/3.26, 358/3.27, 358/463, 345/611, 345/618
• US Class Current: 348/606
• CPC Class Codes: H04N 5/142 Edging; Contouring
• CPC Class Codes: H04N 5/21 Circuitry for suppressing or minimising disturbance, e.g. moiré or halo

Abstract

A method for digitally filtering a video signal comprises: converting the video signal into a plurality of sampled values; determining whether distribution of at least one portion of the sampled values belongs to one of a plurality of specific types according to the sampled values; and generating a plurality of output values according to a correction operation corresponding to the one of the specific types.

Claims

1. An apparatus for digitally filtering a video signal, comprising:

an analog-to-digital converter for converting the video signal into a plurality of sampled values; and

a correction circuit, coupled to the analog-to-digital converter, for determining whether distribution of at least one portion of the sampled values belongs to one of a plurality of specific types according to the sampled values, and compensating the at least one portion of the sampled values according to a correction operation corresponding to the one of the specific types to generate a digital output signal corresponding to the video signal;

wherein the specific types comprise at least one smear effect or at least one ringing effect, wherein the at least one smear effect comprises a pulse smear effect and an edge smear effect, and the at least one ringing effect comprises a rising edge ringing effect and a falling edge ringing effect.

2. The apparatus of claim 1, wherein the specific types comprise the at least one smear effect and the at least one ringing effect.

3. The apparatus of claim 2, wherein the specific types further comprise a mismatch effect.

4. The apparatus of claim 1, wherein the sampled values comprise sequentially generated sampled values X(n−

1), X(n), and X(n+1), and the correction circuit identifies a type of distortion of the video signal as the one of the specific types according to a difference between the sampled values X(n−

1) and X(n) and a difference between the sampled values X(n) and X(n+1).

5. The apparatus of claim 1, wherein the correction operation comprises:

generating a compensation value according to at least two sampled values; and

compensating at least one of the sampled values according to the compensation value to generate an output value of the digital output signal.

6. A method for digitally filtering a video signal comprising:

converting the video signal into a plurality of sampled values;

determining whether distribution of at least one portion of the sampled values belongs to one of a plurality of specific types according to the sampled values; and

generating a plurality of output values according to a correction operation corresponding to the one of the specific types;

wherein the specific types comprise at least one smear effect or at least one ringing effect, wherein the at least one smear effect comprises a pulse smear effect and an edge smear effect, and the at least one ringing effect comprises a rising edge ringing effect and a falling edge ringing effect.

7. The method of claim 6, wherein the sampled values comprise sequentially generated sampled values X(n−

1), X(n), and X(n+1), and the determining step further comprises;

identifying a type of distortion of the video signal as the one of the specific types according to a difference between the sampled values X(n−

1) and X(n) and a difference between the sampled values X(n) and X(n+1).

8. The method of claim 6, wherein the correction operation comprises:

generating a compensation value according to at least two sampled values; and

compensating at least one of the sampled values according to the compensation value to generate at least one of the output values.

9. The method of claim 6, wherein the specific types comprise the at least one smear effect and the at least one ringing effect.

10. The method of claim 9, wherein the specific types comprise a mismatch effect.