WO2003079677A1

WO2003079677A1 - Terminal for displaying a video signal with state based control

Info

Publication number: WO2003079677A1
Application number: PCT/IB2003/000729
Authority: WO
Inventors: Janardhana Bhat; Aloke Gupta; Guo J. Wang
Original assignee: Koninklijke Philips Electronics NV
Current assignee: Koninklijke Philips NV
Priority date: 2002-03-19
Filing date: 2003-02-19
Publication date: 2003-09-25
Anticipated expiration: 2004-09-19
Also published as: AU2003207862A1

Abstract

Terminals (1) like television receivers for displaying video signals comprise video processors (2) for processing said video signals and controllers (6) for in response to control signals controlling said processing. These terminals (1) are provided with selectors (10) for selecting states in dependence of video signal parameters comprising signal-to-noise-ratios and/or signal-strengths. The selectors (10) comprise generators (15) for, per selected state, automatically generating said control signals defining a contrast, a sharpness, a black/blue stretch, a coring, a pre/overshoot-ratio, a peaking, a histogram, a low-noise amplification. Detectors (11) for detecting the switching on of terminals (1) and/or the selection of next television channels are used in combination with (de)activators (12) for in response to detection results (de)activating at least parts of said selectors (10), to get video signals to be displayed which are always processed optimally. The user has the option of switching said selector (10) on and off, and of overruling and getting his/her individual preferences, with a graphical display that can be disabled/enabled.

Description

Terminal for displaying a video signal with state based control

The invention relates to a terminal for displaying a video signal and comprising a video processor for processing said video signal and a controller for in response to control signals controlling said processing.

Such a terminal is for example a television receiver for displaying a video signal received via for example an antenna, a cable, an optical fiber, a satellite receiver etc., or is for example a Universal Mobile Terrestrial System (UMTS) terminal, or is for example a monitor + personal computer, like a desktop, a laptop, a palmtop etc. Said video processor and said controller for example form part of said television receiver, or of said UMTS terminal, or of said computer, etc.

A prior art terminal is known from EP 0 529 522, which discloses a projection television (terminal) for displaying a video signal and comprising an integrated circuit (video processor) for processing said video signal and coupled to control blocks (controller) for generating control signals for controlling said processing. A user generates a peaking signal to be supplied to the peaking control block, and generates a contrast signal to be supplied to the contrast control block, and generates a brightness signal to be supplied to the brightness control block, in response to which said blocks generate said control signals for controlling said processing, which results in the displayed video signal having a user controlled peaking, contrast and brightness. The known terminal is disadvantageous, inter alia, due to the user being required to take care of providing the terminal with (most of the) control information. Especially for an increasing number of different video signals to be displayed (like different television channels or different video signals originating from different sources), and with each video signal being defined by an increasing number of control signals, it gets more and more time-consuming for a human being to provide the terminal with the right information.

It is an object of the invention to provide a terminal as defined in the preamble, which can generate said control signals itself. The invention is defined by the independent claims. The dependent claims define advantageous embodiments. The terminal according to the invention is characterized in that said terminal comprises a selector for selecting a state in dependence of at least one video signal parameter, which selector comprises a generator for generating said control signals in dependence of said selected state. By introducing the selector, in dependence of at least one video signal parameter, like for example the steepness of the video content, a state is selected, for example defining the video signal to be of high bandwidth (high steepness), average bandwidth (average steepness) or low bandwidth (low steepness), and in dependence of said selected state, said generator automatically generates for example five or ten control signals. As a result, a human being is no longer required to provide the terminal with the control information.

The invention is based upon an insight, inter alia, that the human eye is not that sensitive to small differences in displayed video signals, and is based upon a basic idea, inter alia, that for example three or five or ten different states are sufficient for defining the received video signal and for in response generating for example five or ten control signals for controlling the processing of this received video signal.

For example, in case of five different control signals being used for controlling the processing of a video signal, with each control signal having a value being an integer situated in a range from 1 to 10, theoretically a 100,000 different combinations could have been defined, with the human eye however not being able to distinguish between each pair of these 100,000 combinations.

The invention solves the problem, inter alia, of providing a terminal as defined in the preamble, which no longer requires control information from a human being for controlling the processing of a video signal dependency upon the video signal received. It should be noted that EP 0 529 522 discloses an automatic contrast control block, which is automatically deactivated in case of a user having provided the terminal with contrast information defining the contrast to be set above a given threshold. So, from EP 0 529 522 it is known to automatically generate one contrast control signal. It is not known to select one out of many states in dependence of one or more video signal parameters and defining the video signal received and it is not known to generate a group of control signals in dependence of said selected state, with one or more out of said group of control signals being different for each selected state.

It should further be noted that the term "video processor" is to be looked at the broadest possible way and for example not just comprises a main stage like for example a video processing unit but may also further comprise, in addition or alternatively, previous stages (front-end stages) like for example a tuning unit, and/or a demodulating unit and/or an external source.

Embodiments of the controller according to the invention, of the selector according to the invention, of the method according to the invention and of the processor program products according to the invention correspond with the embodiments of the terminal according to the invention.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments(s) described hereinafter.

The drawing illustrates in block diagram form a terminal according to the invention comprising a video processor according to the invention.

The drawing illustrates a teπninal 1 comprising a video processor 2 of which an output is coupled to a display 3 and of which a control input is coupled to an output of a controller 6. A first input of video processor 2 is coupled to an output of a demodulator/tuner/source 4 (demodulator and/or tuner and/or external/internal source and/or further front-end), and a second input of video processor 2 is coupled to an output of a receiver 5. Demodulator/tuner/source 4 further comprises an input for receiving video signals to be displayed and comprises a control in/output coupled to a first control in/output of controller 6 and to control in/outputs of a selector 10. Receiver 5 further comprises an input for receiving for example an infrared signal from a user and comprises a control in/output coupled to a second control in/output of controller 6 and to a further control in/output of selector 10. Selector 10 comprises a detector 11 coupled to said control in/output of demodulator/tuner/source 4 and to an (de)activator 12, a calculator 13, a comparator 14 and a generator 15. Said (de)activator 12 is further coupled to controller 6 and to said control in/output of receiver 5 and to said generator 15. Calculator 13 is further coupled to controller 6 and to said control in/output of said demodulator/tuner/source 4 and to comparator 14. Comparator 14 is further coupled to controller 6 and to generator 15, which is further coupled to controller 6.

The invention relates to a terminal 1 for displaying a video signal and comprising a video processor 2 for processing said video signal and a controller 6 for in response to control signals controlling said processing. Such a terminal 1 is for example a television receiver for displaying a video signal received via for example an antenna, a cable, an optical fiber, a satellite receiver etc., or is for example a Universal Mobile Terrestrial System (UMTS) terminal, or is for example a monitor + personal computer, like a desktop, a laptop, a palmtop etc. Said video processor 2 and said controller 6 for example form part of said television receiver, or of said UMTS terminal, or of said computer, etc.

It is an object of the invention, inter alia, of providing a terminal 1 as defined before, which can generate said control signals itself.

The terminal 1 according to the invention is characterized in that said terminal 1 comprises a selector 10 for selecting a state in dependence of at least one video signal parameter, which selector 10 comprises a generator 15 for generating said control signals in dependence of said selected state.

By introducing the selector 10, in dependence of at least one video signal parameter, like for example the steepness of the video content, a state is selected, for example defining the video signal to be of high bandwidth (high steepness), average bandwidth (average steepness) or low bandwidth (low steepness), and in dependence of said selected state, said generator 15 automatically generates for example five or ten control signals. As a result, a human being is no longer required to provide the terminal with the control information. A first embodiment of the terminal 1 according to the invention is advantageous in that a first video signal parameter comprises a signal-to-noise-ratio of said video signal, with a second video signal parameter comprising a signal-strength of said video signal.

By establishing the first video signal parameter in the form of a signal-to- noise-ratio of said video signal (standard procedure in well known video processors available on the market) by for example measuring the noise signal in the Root Mean Square (RMS) value of the Alternating Current (AC) content of the video signal, during a vertical flyback period of the video signal when scanning the blank horizontal lines, and dividing a peak-to- peak video signal by this noise signal, and by establishing the second video signal parameter in the form of a signal-strength of said video signal (standard procedure in well known video processors available on the market), by for example measuring a RMS value of the video signal, two video signal parameters are used each for well defining a quality of the received video signal. This quality forms a good basis for defining said states. Of course, both video signal parameters can be used independently from one another and do not necessarily need to be used in combination with each other. The first video signal parameter in the form of a signal-to-noise-ratio of said video signal defines a signal-to-noise-quality advantageously, and the second video signal parameter in the form of a signal-strength of said video signal defines a signal-strength-quality advantageously. A second embodiment of the terminal 1 according to the invention is advantageous in that said terminal 1 comprises a detector 11 for detecting a predefined change in said video signal and a (de)activator 12 for in response to a detection result (deactivating at least a part of said selector 10.

By introducing the detector 11 for detecting a predefined change in said video signal, like for example the switching on of the terminal 1 and/or the selection of a next video signal (like a next television channel or a next video signal originating from a next source), and by introducing the activator 12 for in response to a detection result activating at least a part of said selector 10, in response to the predefined change, the one or more video signal parameters for the new video signal are established, possibly resulting in a new state and a generation of new control signals. As a result, the video signal to be displayed is always processed optimally. Said detector 11 may form part of said selector 10 or not. Said (de)activator 12 may form part of said selector 10 or not.

A third embodiment of the terminal 1 according to the invention is advantageous in that said control signals define control parameters corresponding with a contrast, and/or a sharpness, and/or a black stretch, and/or a blue stretch, and/or a coring, and/or a pre/overshoot-ratio, and/or a peaking, and/or a histogram, and/or a low-noise amplification.

These different control signals together allow said controlling of said processing of said video signal to be done most extensively. But of course, all control signals can be used independently from one another and do not necessarily need to be used in combination with each other. And further control signals are not to be excluded: in addition to image parameters like said contrast - histogram, further control parameters available in the video processor could be used, and said low-noise amplification being a front-end parameter could for example be supplied to the tuning unit, and/or to the demodulating unit and/or to the external source, together with further front-end parameters. A state will usually define at least two different control signals, and in dependence of a selected state usually at least two different control signals will be generated. But exceptions are not to be excluded.

A fourth embodiment of the terminal 1 according to the invention is advantageous in that said terminal 1 comprises a receiver 5 for receiving a (de)activation signal from a user and to be supplied to said (de)activator 12 for overruling said detection result and (de)activating at least apart of said selector 10.

By introducing said receiver 5 for receiving a (de)activation signal from a user to be supplied to said (de)activator 12 for overruling said detection result and (de)activating at least a part of said selector 10, the user has the advantageous option of switching at least a part of said selector 10 on and off.

A fifth embodiment of the terminal 1 according to the invention is advantageous in that said terminal 1 comprises said receiver 5 for receiving further control signals from said user and to be supplied to said controller 6 for overruling corresponding control signals.

By introducing said receiver 5 for receiving further control signals from said user and to be supplied to said controller 6 for overruling corresponding control signals, the user still has the advantageous option of overruling and getting his/her individual preferences. A sixth embodiment of the terminal 1 according to the invention is advantageous in that said terminal 1 comprises said receiver 5 for receiving a disable/enable signal from a user and to be supplied to said controller 6 for disabling/enabling a graphical display of said control signals.

By introducing said receiver 5 for receiving a disable/enable signal from a user and to be supplied to said controller 6 for disabling/enabling a graphical display of said control signals, the user has the advantageous option of switching the graphical display of said control signals on and off. Especially when zapping, in other words when changing a television channel and/or a source every second or so, the graphical display of control signals would make it difficult to get a quick impression of the information offered via this channel and/or source.

Chronologically, terminal 1, in case of being a television receiver, functions as follows. After being switched on, demodulator/tuner/source 4 selects one out of many video signals arriving at its input and supplies this video signal (after demodulation and/or conversion) to video processor 2 and informs controller 6 by supplying at least predefined parts of the demodulated and/or converted video signal to controller 6 and selector 10.

In selector 10, detector 11 detects a predefined change in the video signal, and informs (de)activator 12 that selector 10 in general or generator 15 more particularly is to be activated. Calculator 13 under control of controller 6 calculates either a first video signal parameter corresponding with a signal-to-noise-ratio of said video signal or a second video signal parameter corresponding with a signal-strength of said video signal or a third video signal parameter corresponding with a steepness of the content of said video signal or a fourth signal parameter corresponding with a further video signal definition of said video signal or two or more out of these four video signal parameters, and supplies them to comparator 14 which under control of controller 6 compares each one of them with predefined thresholds for example supplied by controller 6 or for example based upon said calculations or for example based upon previous calculations.

Either the combination of these comparison results in comparator 14 define a state, which information is supplied to generator 15, or the combination of these comparison results in comparator 14 are supplied to controller 6 for defining said state, which information is then supplied to generator 15, or the combination of these comparison results in comparator 14 are supplied to generator 15, which in response defines said state. In response to the state defined, generator 15 generates control signals like a contrast, and/or a sharpness, and/or a black stretch, and/or a blue stretch, and/or a coring, and/or a pre/overshoot-ratio, and/or a peaking, and/or a histogram, and/or a low-noise amplification etc., each one having a value dependently upon the state defined, which control signals are supplied to controller 6 for controlling video processor 2 for displaying said video signal via display 3. Then a user decides to change the television channel, for example. Thereto, said user uses his/her remote control, which transmits for example an infrared signal to receiver 5 and defining the next television channel to be displayed. Receiver 5 supplies this information to controller 6, which controls demodulator/tuner/source 4 in such a way that said new television channel is selected (tuned). Demodulator/tuner/source 4 selects this new video signal and supplies this new video signal (after demodulation and/or conversion) to video processor 2 and informs controller 6 by supplying at least predefined parts of the demodulated and/or converted new video signal to controller 6 and selector 10. In selector 10, detector 11 detects the predefined change in the video signal (the arrival of this new video signal compared to the previous video signal), and informs (de)activator 12 that selector 10 in general or generator 15 more particularly is to be activated. At the same time, calculator 13 under control of controller 6 calculates one or more of said video signal parameters, and supplies them to comparator 14 which under control of controller 6 compares each one of them with predefined thresholds for example supplied by controller 6. In response to the comparison results, a state is defined. In response to the state defined, generator 15 generates said control signals, each one having a value dependently upon the state defined, which control signals are supplied to controller 6 for controlling video processor 2 for displaying said new video signal via display 3.

For example via said remote control and receiver 5, said user has further options, like transmitting a (de)activation signal to be supplied to said (de)activator 12 for overruling said detection result and (deactivating said selector 10 in general or generator 15 more particularly, to switch selector 10 in general or generator 15 more particularly on and off. Said user can further transmit further control signals to be supplied to said controller 6 for overruling corresponding control signals, to get his/her individual preferences. And said user may transmit a disable/enable signal to be supplied to said controller 6 for disabling/enabling a graphical display of said control signals, to switch the graphical display of said control signals on and off, to prevent that, for example during zapping, in other words when changing a television channel every second or so, the graphical display of control signals is shown after each channel change (this would make it difficult to get a quick impression of the information offered via this channel).

Said states and control signals are for example as follows. Table 1

As disclosed in table 1, four states dependently upon the signal strength can be distinguished, with each state defining a first control signal "pic control" (contrast and sharpness), a second control signal "black/blue stretch", a third control signal "coring" and a fourth control signal "LNA" meaning low noise amplification. These control signals are generated by generator 15 in dependence of the state defined, and supplied to confroller 6 for controlling said video processing.

As disclosed in table 2, five states dependently upon the signal strength can be distinguished, with each state defining a first control signal "black stretch", a second control signal "coring", a third control signal "pre/overshoot" and a fourth control signal "peaking". These control signals are generated by generator 15 in dependence of the state defined, and supplied to controller 6 for controlling said video processing.

Each block shown or not shown, can be 100% hardware, 100% software or a mixture of both. Each block shown or not shown can be integrated with each other block shown and/or not shown. Especially (parts of) selector 10 and controller 6 will generally be integrated with each other due to both being realizable via a processor/memory. But detector 11 and calculator 13 may alternatively be integrated with demodulator/tuner/source 4, or with video processor 2, and (de)activator 12 may alternatively be integrated with receiver 5. Controller 6 and (parts of) selector 10 may further be integrated entirely or partly with video processor 2. Selector 10 may comprise its own processor/memory, or may use controller 6 for processing capabilities. Calculator 13 and comparator 14 are just examples, alternatives are possible, like using video processor 2 for establishing said video signal parameters. Generator 15 for example comprises a table memory for in response to an input signal defining a row or a column generating output signals stored in said row or said column, and (de)activator 12 for example corresponds with a generator for receiving and or generating (de)activation signals.

Alternative video signal parameters are not to be excluded, and video signal parameter signals do not necessarily need to be calculated but could alternatively or in addition for example already form part of the video signals received by demodulator/tuner/source 4. Demodulator/tuner/source 4 and receiver 5 may comprise their own processor/memory, or may use controller 6 for processing capabilities. Each unit shown or not shown may further comprise buffers for temporarily buffering signals and may be mainly analog, mainly digital, or a combination of both. Alternative detections, generations, calculations, comparisons, (de)activations, and/or functions are not to be excluded, like for example using a first video signal parameter for selecting a first state out of a first group of first states and in response generating a first number of first control signals, and in addition using a second video signal parameter for selecting a second state out of a second group of second states and in response generating a second number of second control signals, etc. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

CLAMS:

1. Terminal (1) for displaying a video signal and comprising a video processor (2) for processing said video signal and a controller (6) for in response to control signals controlling said processing, characterized in that said terminal (1) comprises a selector (10) for selecting a state in dependence of at least one video signal parameter, which selector (10) comprises a generator (15) for generating said control signals in dependence of said selected state.

2. Terminal (1) according to claim 1, characterized in that a first video signal parameter comprises a signal-to-noise-ratio of said video signal, with a second video signal parameter comprising a signal-strength of said video signal.

3. Terminal (1) according to claim 2, characterized in that said terminal (1) comprises a detector (11) for detecting a predefined change in said video signal and a (de)activator (12) for in response to a detection result (de)activating at least a part of said selector (10).

4. Terminal (1) according to claim 3, characterized in that said control signals define control parameters corresponding with a contrast, and/or a sharpness, and/or a black stretch, and or a blue stretch, and/or a coring, and or a pre/overshoot-ratio, and or a peaking, and/or a histogram, and/or a low-noise amplification.

5. Terminal (1) according to claim 4, characterized in that said terminal (1) comprises a receiver (5) for receiving a (de)activation signal from a user and to be supplied to said (de)activator (12) for overruling said detection result and (de)activating at least a part of said selector (10).

6. Terminal (1) according to claim 5, characterized in that said terminal (1) comprises said receiver (5) for receiving further control signals from said user and to be supplied to said controller (6) for overruling corresponding control signals.

7. Terminal (1) according to claim 6, characterized in that said terminal (1) comprises said receiver (5) for receiving a disable/enable signal from a user and to be supplied to said controller (6) for disabling/enabling a graphical display of said control signals.

8. Controller (6) for use in a terminal (1) for displaying a video signal and comprising a video processor (2) for processing said video signal and said controller (6) for in response to control signals controlling said processing, characterized in that said controller (6) comprises a selector (10) for selecting a state in dependence of at least one video signal parameter, which selector (10) comprises a generator (15) for generating said control signals in dependence of said selected state.

9. Selector (10) for use in a terminal (1) for displaying a video signal and comprising a video processor (2) for processing said video signal and a controller (6) for in response to control signals controlling said processing, characterized in that said selector (10) selects a state in dependence of at least one video signal parameter and comprises a generator (15) for generating said control signals in dependence of said selected state.

10. Method of displaying a video signal, the method comprising the steps of processing said video signal, and in response to control signals controlling said processing, characterized in that said method comprises the steps of in dependence of at least one video signal parameter selecting a state, and in dependence of said selected state generating said control signals.

11. Processor program product to be run via a video processor and comprising the functions of processing said video signal and of in response to control signals controlling said processing, characterized in that said processor program product comprises the functions of in dependence of at least one video signal parameter selecting a state and of in dependence of said selected state generating said control signals.

12. Processor program product for use in combination with a video processor for processing said video signal and for in response to control signals controlling said processing, characterized in that said processor program product comprises the functions of in dependence of at least one video signal parameter selecting a state and of in dependence of said selected state generating said control signals.