Abstract:
An apparatus, method and system for transmitting a video signal and picture correction information therefor via a satelite or like transmission system. Mechanisms for, receiving a transmitted video signal and correction information and for processing a received video signal based on the correction information before display are also disclosed.

Description:
FIELD OF THE INVENTION 
     The present invention relates to satellite television broadcast systems and, more specifically, to improving the picture provided by such systems. 
     BACKGROUND OF THE INVENTION 
     Recently, there has been growth in the field of satellite broadcast television systems. These systems usually have many channels, some over one hundred, and typically employ an on-screen menu for program selection. 
     Due in part to the large number of channels, a wide range of programs are available. There are channels that carry exclusively sports, old movies, shopping, etc. There are channels that show a variety of programs including old sit-coms, new movies, talk shows, major sports, entertainment and political events, etc. There is also outdoor programming, as well as general information and advertising, amongst others, as is known. It should be recognized that the optimum picture parameter settings for these different types of programming may vary. To some extent, the contrast, brightness and color buttons on a television monitor assist a viewer in compensating for these variances. For example, an old black and white sit-com may have different optimum picture parameter settings than a day-time football game, etc. 
     The quality of the picture projected on a television monitor or projection screen also depends on the quality of the original program, the manner in which the program was recorded and stored and the transmission media used for distribution, for example, there are inherent losses in clarity and other picture parameters during transmission. 
     A need exists for improving or otherwise affecting the picture of a program transmitted via a satellite broadcast or like transmission system to accommodate for both varying different optimum picture parameter settings and losses during transmission, amongst other consideration. 
     In addition, the human eye is capable of detecting a dynamic range of picture parameters beyond that which is currently broadcast. A need also exists for expanding the dynamic range of picture parameters provided to the end user. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide an improved picture to users of satellite broadcast systems. 
     It is also an object of the present invention to permit a satellite broadcaster or an end user to select desired picture parameter settings. 
     It is another object of the present invention to increase the dynamic range of picture parameters provided with a satellite broadcast system. 
     These and related objects of the present invention are achieved by use of a satellite broadcast video picture improving apparatus and method as described herein. 
     The attainment of the foregoing and related advantages and features of the invention should be more readily apparent to those skilled in the art, after review of the following more detailed description of the invention taken together with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagram of a satellite television broadcast system in accordance with the present invention. 
     FIG. 2 is a diagram of correction circuitry in accordance with the present invention. 
     FIG. 3 is a representation of a serial stream of menu channel data in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIG. 1, a diagram of a satellite television broadcast system  5  in accordance with the present invention is shown. A colorist or other suitable person  10  previews a program before transmission and determines which picture parameter settings or, more specifically, which correction values provide a desired picture presentation. In a manner discussed in more detail below, the colorist or operator makes a selection that results in the designation of a particular “code” that represents a selected combination of picture parameter correction values. 
     The programs which are to be broadcast by the satellite system provider are propagated to satellite broadcast antenna  14  from which they are transmitted, each preferably at a different frequency as is known. A separate menu channel is also transmitted and a code that represents the selected combination of picture parameter correction values (for each program so enabled) is preferably transmitted via the menu channel signal. 
     Antenna  14  transmits the programs and menu channel data to a satellite  16  from which they are redirected to a user&#39;s receiving antenna  18 . The receiving antenna is preferably connected to a set-top box (STB) that preferably includes a tuner (as is known) and that controls the programming displayed on monitor  22 . The set-top box is in turn often controlled by a user directed remote control device  24  or by user selected external controls. 
     The present invention includes the placement in a STB or a receiving monitor (or in or in communication with other receive side components) of circuitry responsive to a transmitted code for improving or otherwise affecting the picture generated from the transmitted video signal based on that code. In the text that follows the correction circuitry is described as being within a STB. While this is done because placement in a STB is an envisioned commercial product, it should be recognized that the correction circuitry can be placed elsewhere in the signal path as alluded to in the beginning of this paragraph. In the text that follows, the circuitry for correcting the video signal is described first followed by a description of code formation. 
     Referring to FIG. 2, a diagram of correction circuitry  40  in accordance with the present invention is shown. A common format for video signal processing includes separation of the luminance and the chrominance components of a video signal. Since standard circuitry for video signal and, more specifically, luminance and chrominance signal propagation is known in the art, this standard circuitry is not shown or discussed herein. It would be apparent, however, to one skilled in the art that on the received video processing side the luminance and chrominance signals may be separated. The circuitry of FIG. 2 is to be inserted in video processing logic in the separated luminance and chrominance signal paths as shown. 
     Circuit  40  includes processing logic  45 , a look-up table (LUT)  50  and a plurality of picture parameter correction circuits, amongst other components. As discussed in more detail with reference to FIG. 3, the code or codes for a particular program in addition to time and program name information is preferably transmitted in the menu channel. Data in the menu channel is preferably in a serial format and streams into processing logic  45  over line  44  (when the tuner is tuned to the menu channel) from where the data is written to appropriate locations in memory  46 . IR control over link  43  permits a user to select which portion of the menu data appears on monitor  22 . In response to a user&#39;s selection, processing logic  45  outputs from memory the requested portion of the menu in a known manner. It should be recognized that there are often over one hundred channels and program information for all of these channels cannot be viewed on a monitor at the same time. 
     In conventional systems, a user typically selects a program by highlighting the program on the on-screen menu and depressing the “select” button on the hand-held remote unit. This form of operation is supported by circuit  40 . In response to depression of a select button or the like, processing logic  45  preferably outputs a signal over line  47  which causes the tuner to change to the frequency of the requested program. Processing logic  45  also propagates the picture parameter correction code for the selected program from memory  46  to LUT  50  over line  48 . LUT  50  is preferably a 256×5 8-bit word table. The 5 8-bit words preferably provide correction values for intensity (I), clarity (CY), noise reduction (NR), black level (B), and color (CR) While these parameters are preferred, it should be recognized that the use of less than these five parameters or the inclusion or substitution of one or more other related parameters is within the scope of the present invention. As an example of the manner in which the correction values are addressed, if the code transmitted through the menu channel signal and stored in memory  46  is 00110101 this may address the location for I=55, CY=20 NR=35, B=30 and CR=90, where these numbers represent a relative magnitude that is predetermined and preprogrammed by a user/provider as discussed below. 
     The 8-bit correction values for each parameter are propagated over lines  60 - 64  to respective digital to analog converters (DACs)  70 - 74 . The DACs convert the digital (e.g., binary) correction value to an analog voltage that is preferably fed to voltage controlled amplifiers/attenuators  80 ,  82 - 84  or another suitable attenuation device (except in the case of noise reduction correction as discussed below). 
     The intensity circuit  52  preferably includes a 2× gain amplifier and receives the input luminance signal propagated over line  41 . The amplified luminance signal is propagated to the voltage controlled attenuator where the output of DAC  70  controls the percent of attenuation (from 0 to 100%) the amplified luminance signal is subjected to. The combination of this amplification and attenuation increases the dynamic range of the intensity component of the subject video signal. 
     Clarity circuit  53  also receives the luminance signal. Clarity circuit  53  preferably generates correction pulses to improve the shape of luminance transitions. The known art teaches generation of a correction pulse with a differentiation circuit. The output of the differentiator circuit is preferably filtered, for example, with an RCL filtering device  54  or the like. In a preferred embodiment, the noise reduction correction value propagated over line  61  is connected to an analog signal and used to select a variable resistance in the filter or noise reduction circuit  55 . The filter preferably modifies the width of the correction pulse by removing harmonics, etc. The clarity correction value propagated on line  62  controls variable gain amplifier/attentuator  82 . Attenuator  82  preferably provides amplitude adjustment of the filtered correction pulse. 
     The black level correction value propagated over line  63  controls the output of attenuator  83 . Black level circuit  56  is essentially a DC voltage source that generates a reference voltage which can be added or subtracted from the background black level to make a picture appear lighter or darker. Attenuator  83  permits provider selection of the amount of the output of circuit  73  that is added to the luminance signal. 
     The outputs of attenuators  80 ,  82 - 83  are added together to create the improved or otherwise affected luminance signal which is output at port  91 . 
     With respect to the chrominance signal which is input over line  42 , color circuit  57  preferably provides a 1.5× gain of this signal, thereby increasing the dynamic range thereof. The color correction value propagated over line  64  controls the output of attenuator  84  in the same manner as discussed above for the other attenuators and hence controls the amount of the original chrominance signal that is output to port  92 . 
     Referring to FIG. 3, a representation of a serial stream  100  of menu channel data in accordance with the present invention is shown. Starting at an arbitrary point in the stream, a channel indicator or code  101  is provided along with a channel number  102 , for example,  42 . This is followed by a time indicator  103  and the time in ASCII characters  104  that a program starts, for example, 1:30 pm. This is followed by a title indicator  105  and the accompanying title in ASCII characters  106 , for example, “Hogan&#39;s Heroes.” This is followed by a correction code indictor  107  and the accompanying code  108 , for example, 00110101. These four blocks of information for channel  42  may be followed by additional information for channel  42  or information for another channel. As an alternative to providing an indicator or heading for each datum, it is also contemplated to provide an ordered field arrangement so that the information can be stripped out of sequential fields, eliminating the space utilized by the indicators/headers. 
     The channel time and program information is currently stripped off and stored in memory  46  with known processing technology. Correction code data is preferably stripped off and stored in a similar manner. 
     With respect to initial selection of the codes for the correction value combinations, the most common combinations (developed from empirical data) and other desired combinations, such as pass through and test patterns are determined and coded. These codes are then provided to the colorist. In one preferred embodiment, the colorist views a program and using individual controls (for example through a graphic user interface in encoding equipment  12 ) determines what the desired parameter correction values are for each picture parameter. The colorist then invokes a best-fit software algorithm of a type known in the art to find which of the precoded combinations most closely matches that which he or she determined with individual controls. That code is saved and placed in the appropriate memory location for subsequent insertion into the appropriate field (e.g., field  108  of FIG. 3) of the menu channel data stream. 
     As an alternative to individual selection of parameter correction values, a number of predetermined correction value combinations or “categories” may be defined and selected from. These preferably include the following and the like: indoors sports, outdoor sports—night, outdoor sports—day, drama, music video, western, black &amp; white, action, nature, documentary, live news, talk-show, variety show, special event, cartoon, etc. 
     Though the above description described the substantially parallel transmission of programs and correction codes, and the automatic incorporation of the correction codes, logic  45  may be configured to also write the codes to a portion of memory  46  that a user can select from and scroll through using remote control unit  24 . In this manner, preferred picture parameter correction values can be selected by a user. 
     While the above teaching is directed towards a satelite broadcast system, it should be recognized that the above teachings can be applied to other media such as VCR, DVD, laser dick, etc. For example, the correction code can be placed in the control track or supplemental audio program (SAP) or the like and streamed out with the control or SAP information. 
     While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention and the limits of the appended claims.