MXPA01005321A - Picture signal processing - Google Patents

Abstract

In a picture signal processing method, an analog picture signal (APS1, APS2) is processed (PSP) in dependence on a quality indication (QI1, QI2) relating to the analog picture signal (APS1, APS2) and received together with the analog picture signal (APS1, APS2). Preferably, the analog picture signal (APS1, APS2) has been obtained from a digital picture signal that has been encoded at a bit-rate and/or at a compression ratio and/or at a quantization level, wherein the quality indication (QI1, QI2) is the bit-rate and/or the compression ratio and/or the quantization level.

Description

PROCESSING OF SIGNALS OF IMAGES The invention relates to a method and device for processing image signals, a method and device that supplies image signals, a television receiver, a recorder / player and an image signal receiver.

It is known to use motion vectors transmitted as part of a signal MPEG both in an MPEG decoder and in a post-processing circuit to improve MPEG decoder signal production, for example, by doubling the field average. See WO-A-97/46022, section V (List of lawyers' cases PHN 16,112).

It is, among other things, an object of the invention to provide improved image signal processing. In this regard, the invention provides a method and device for processing image signals, a method and device that supplies image signals, a television receiver, a recorder / player and an image signal receiver as defined in the claims. independent Favorable characterizations are defined in the dependent claims. In an image signal processing method according to an aspect of the invention, an analog image signal is processed depending on a quality indication related to the analog image signal and received together with the analog image signal. Preferably, the analog image signal was obtained by decoding a digital image signal that was obtained by coding on a bit average and / or a compression ratio and / or a quantization level, where the quality indication is the bit average and / or the compression ratio and / or the quantization level and / or other information on the encoding or decoding. These and other aspects of the invention will be apparent and will be elucidated with reference to the characterizations described hereinafter.

The drawing shows a configuration comprising characterizations of a (DVD) recorder / player, a set-top-box and a television receiver according to the present invention.

An RP recorder / player comprises a DEC1 decoder (such as an MPEG decoder, alternatives are possible) for decoding a digital picture signal retrieved from a storage medium such as a digital versatile disk (DVD). Other means of digital recording, such as a cassette, are possible alternatives. The RP recorder / player may have an antenna input to receive a digital image signal. In this way, decoder DEC1 can be used for stored signals and for signals received from the air (or via cable). In accordance with the present invention, the decoder DEC1 not only supplies a first decoded analog picture signal APS1, but also a first quality indication QI1 corresponding to the first analog picture signal APS1. Preferably, the first quality indication QI1 is the bit average and / or the compression ratio and / or the quantization level at which the digital image signal has been encoded and / or other information about the coding or decoding, said information on the level of compression via an inverse quantization process and / or quantifier matrix (for intra or non-intra-images) when the basic ones are not being used and / or intra-dc-accuracy and / or information when it has occurred a decoding error.

The drawing further shows an image signal receiver in the form of a set-top box STB comprising a reader for a smart card SC and a decoder DEC2 corresponding to the decoder DEC1 for decoding a received digital image signal of an A2 antenna or through cable. The decoder DEC1 supplies a second analog image signal APS2 and a corresponding second quality indication AI2. A TV receiver includes inputs for analog picture signals APS1, APS2 and the corresponding quality indications AI1, AI2. The connections between the RP recorder / player and the TV set can be through a well known SCART cable for a parallel transmission of the analog image signal APS 1/2 and the corresponding quality indication QI1 / 2. Or through a serial connection like USB. As a further alternative, the Q 1/2 quality indication can be transmitted within the corresponding analogue image signal APS 1/2, for example, on a teletext line of the analogue image signal APS1 / 2. A switch S1 selects the first analog image signal APS1 or the second analog image signal APS2 to obtain a selected analog image signal. A switch S2 selects a first quality indication QI1 or the second quality indication QI2 to obtain a selected quality indication. Switches S1 and S2 can belong to a single electronic switch unit. The selected analog image signal is subject to PSP image signal processing, such as an image signal enhancement as a main operation, noise reduction operation, MPEG artifact reduction operation, centering operation or histogram operation. The processing of PSP image signals is controlled by an image signal control that depends on the selected analog image signal and the selected quality indication. The resulting processed image signal is displayed on a DD display device. The invention is based on the recognition that the sending of a quality indication with an analogue image signal allows the TV to determine the characteristics of the source material and therefore makes an informed selection of algorithm. A better quality of image will result from the application of a process more appropriate to the signal. If an image signal processing unit is given the information it needs to enable it to do an adequate optimization, this prevents the "optimization" of an image that is already good, or the "optimization" of it in an erroneous way. For example, if the quality of the analog image signal is low, because the digital image signal from which the analog image signal has been recovered has been encoded at a low quantization level, a low bit average and / or a high compression radius, an image signal enhancement operation as a main operation or a histogram to improve brightness and / or contrast would only make the blocking artifacts more visible. Therefore, if the quality indication indicates a low quality, preferably a main operation is turned off. On the other hand, the mosquito noise present in a low quality signal can be reduced by properly adjusting a noise reduction operation that is part of the processing of PSP image signals depending on the quality indication. The TV can accommodate different sources, with different signal qualities (and possibly changing them dynamically). While in the characterization, the TV receiver has two inputs (APS1, QI1) and (APS2, QI2), it is not necessary to have two sources in the system for the invention to have a benefit. It should be noted that the above-mentioned characterizations illustrate rather than limit the invention, and those skilled in the art will be able to design various alternative characterizations without departing from the vision of the appended claims. The RP recorder / player may have recording facilities, and the notion recorder / player includes any apparatus that is capable of reproducing and decoding a recorded digital image signal to obtain a similar image signal in addition to a corresponding quality indication. In the claims, any reference sign placed between the parentheses will not be construed as limiting the claim. The word "comprises" does not exclude the presence of elements or steps other than those that were listed in a claim. The word "a" or "an" before an element does not exclude the presence of a plurality of said elements. The invention can be implemented by hardware comprising several different elements, and through a properly programmed computer. In the device claim that enumerates several means, several of these elements can be characterized by a hardware article. The simple fact that certain measures that are recited in the mutually different subordinate claims does not indicate that a combination of these measures can not be used to take advantage of them.

Claims (13)

1. CHAPTER CLAIMING Having described the invention, it is considered as a novelty and, therefore, the content is claimed in the following: 5 CLAIMS 1. A method of processing image signals, comprising the steps of: receiving an analog image signal (APS1, APS2) and a quality indication (QI1, QI2) related to the analog image signal (FIG. APS1, APS2); and 0 processing (PSP) of the analog image signal (APS1, APS2) depending on the quality indication (QI1, QI2).
2. 2. A method as claimed in claim 1, wherein the processing step (PSP) includes an image enhancement operation. c;
3. 3. A method as claimed in claim 2, wherein the image enhancement operation (PSP) is a contrast and / or brightness enhancement operation.
4. 4. A method as claimed in claim 2, wherein the operation of 0 image enhancement (PSP) is a noise reduction or coding artifact operation.
5. 5. A method as claimed in claim 1, wherein the analog image signal (APS1, APS2) has been obtained by decoding a digital image signal that has been obtained by coding at a bit average and / or a compression ratio and / or a quantization level, and wherein the quality indication (QI1, QI2) is the bit average and / or the compression ratio and / or the quantization level and / or other information on the coding and decoding.
6. 6. An image signal processing device, comprising: means for receiving an analog image signal (APS1, APS2) and a quality indication (QI1, QI2) related to the analog image signal; and means (PSP) for the processing of analog image signals (APS1, APS2) depending on the quality indication (QI1, QI2).
7. 7. A television receiver (TV) comprising: an image signal processing device (PSP) as claimed in claim 6 for providing a processed image signal; and means (DD) to display the processed image signal.
8. 8. A method that supplies an image signal, comprising the steps of: supplying an analog image signal (APS !, APS2); and providing a quality indication (QI1, QI2) related to the analog image signal (APS1, APS2).
9. 9. A method as claimed in claim 8, wherein the analog image signal (APS1, APS2) has been obtained by decoding a digital image signal that has been obtained by coding at a bit average and / or a radius of compression and / or a quantization level, and wherein the quality indication (QI1, QI2) is the bit average and / or the compression ratio and / or the quantization level and / or other information about the coding and decoding
10. 10. A device that supplies image signals, comprising: means for supplying an analog image signal (APS1, APS2); and means for supplying a quality indication (QI1, QI2) related to the analog image signal (APS1, APS2).
11. 11. A device that supplies image signals as claimed in claim 10, further comprising: means for decoding (DEC1, DEC2) a digital image signal that has been obtained by coding at a bit average and / or a radius of compression and / or a quantization level, to provide the analog image signal (APS1, APS2), the quality indication (QI1, QI2) being the bit average and / or the compression ratio and / or the quantization level and / or other information about the encoding or decoding.
12. 12. A recorder / player (RP), comprising: means for recovering a digital image signal from a recording (DVD); and a device that supplies image signals (DEC1) as claimed in claim 11.
13. 13. An image signal receiver (STB), comprising: means (A2) for receiving a digital image signal; and a device that supplies image signals (DEC2) as claimed in claim 11.