Television – Image signal processing circuitry specific to television
Reexamination Certificate
1998-04-07
2002-04-16
Eisenzopf, Reinhard J. (Department: 2614)
Television
Image signal processing circuitry specific to television
C348S650000, C348S575000, C348S576000, C348S722000, C382S162000
Reexamination Certificate
active
06373529
ABSTRACT:
FIELD OF INVENTION
The present application relates to image processing and in particular to electronic and computer techniques to enhance the editorial effects that can be produced with motion picture images resulting from film or video.
BACKGROUND OF THE INVENTION
Machines to produce electrical signals from motion picture film have been known for many years. References exist showing that such processes were known in the 1920's and used by John Logie Baird. Examples of current machines (‘telecine machines’) to perform this function include the URSA ‘Diamond’ machine manufactured by Cintel International Ltd. of Ware, Hertfordshire, and the ‘SPIRIT Datacine’ from Philips, Darmstadt, Germany.
These systems permit some editorial adjustment to the electrical images produced from the film to be made. These functions usually include the adjustment of gain (white level), lift (black level), and gamma (contrast and midtone). Some telecine machines also contain primary and secondary colour correction systems. Primary colour correction is the adjustment of the primary colour content of the image. For example, all areas containing red may be made redder i.e. the level of red in the whole image may be increased. This will necessarily affect the grey tones which are composed of equal components of red, green, and blue. Secondary colour correction is the adjustment of particular colours in the image and, for example, distinctions may be made between areas containing solely red, and areas containing red in conjunction with other colours, such as grey areas.
It is commonly preferred for telecine users and owners to purchase separate colour correction systems to those included in some telecine machines. An example of such a system is the ‘DCP’ system manufactured by Pandora International Ltd. Many aspects of this system are disclosed in U.S. Pat. No. 5,450,500, International patent application WO 95/12289, and others.
As is disclosed in U.S. Pat. No. 5,450,500, the DCP system is capable of identifying a particular area of an image and, if required, adjusting the appearance of the image to achieve a desired effect. The area to be adjusted may be identified by one or more criteria including the luminance, hue, saturation, position or texture of one or more of its constituent pixels. The DCP is equipped with eight channels each of which can be configured to perform a separate adjustment on an individually defined area of the image. Each pixel in the stream of digital video data from a telecine machine or video source is tested sequentially by each successive channel of the DCP for correspondence with the predetermined criteria stored in that channel. If the pixel meets the criteria of a particular channel it is tagged for adjustment in accordance with the adjustment parameters defined in that channel. The adjustment parameters may include adjustment of one or more of the luminance, hue, saturation or position of the pixel. Thus, each of the channels will adjust the appearance of the pixel under test if it meets the adjustment criteria of that channel. The channels are designed such that each channel in turn can test the input video data stream at a sufficiently high speed that the DCP produces a corrected video data stream at broadcast rate.
There is, however, a trend in the television and video post-production industry to move away from the traditional ‘clocked’ processing of television images, whereby video frame rates are matched to the broadcast rate of 50 or 60 Hz, so that each television line is processed in exactly one 625th or 525th of the picture frame rate. Modern trends are to process images asynchronously, where data calculations take as long as necessary, provided that the average data processing rate matches the expected rates. Sometimes, it is not even necessary to match average real time or broadcast rates, as some processing in this ‘computer’ format is acceptable in non-real time.
Traditionally, video data has been stored on video tape and, in particular, digital video data has been stored on digital video tape. However, digital video tape can only be used to record data at real time rates. The advent of large capacity magnetic storage media such a hard disks has meant that video data can be stored and accessed at rates faster than real time. Video colour correctors on the other hand remain configured to process video data at real time rates.
SUMMARY OF THE INVENTION
Viewed from one aspect the present invention provides a method for the processing of video data in which the appearance characteristics of picture elements are modified using digital apparatus which provides a plurality of channels having respective processing means, each channel being adapted normally to operate to process a discrete range of characteristics, wherein the method comprises the step of operating the apparatus in an alternative mode in which at least two of the channels are used to carry out identical processing steps, spatial segments of the video data being split between said at least two channels to thereby increase the speed of processing.
Preferably the digital apparatus is a digital colour processing unit in which video data may be passed in sequence through selection means for each channel which determines whether pixels are to be modified in accordance with selection criteria for that channel, and wherein the digital colour processing unit is further provided with routing means for operating the unit in an alternative mode in which data is passed in parallel through at least two of the selection means, said at least two of the selection means having identical selection criteria and the associated channels modifying selected pixels in an identical way.
Viewed from another aspect the present invention provides a method of processing a stream of video data, wherein the data stream is split into a plurality of sequential portions and the portions are routed to a corresponding plurality of processing units each configured to perform an identical operation on the data.
Viewed from another aspect the present invention provides apparatus for the processing of a continuous stream of video data, the apparatus comprising a plurality of processing units for processing the video data and routing means for routing successive portions of the data stream respectively to at least two of the processing units, when said at least two processing units are configured to perform an identical processing operation on the video data.
In accordance with the present invention the video data stream may be processed faster than the individual capability of each processing unit as each processing unit will be operating on only a portion of the video data. The processing units will therefore operate on the video data in parallel when they are performing identical operations.
The number of portions into which the data stream is split will be determined in practice by reference to the number of available processing units and the number of separate simultaneous operations required. For example, in a system of six processing units, or channels, required to carry out only two modifications, the video data stream will be split into three successive portions and each portion will be routed through two processing units, each of the two processing units performing a respective modification.
Reconstituting means may also be provided for reconstructing the split portions of the data stream back into a single stream after processing.
The number of processing channels used may be altered dynamically. For example, an image may require only a simple correction for one part of the image, such as the adjustment of one colour, and this may be done using one processor only. Elsewhere in the image there may be a region where a complicated change is required, involving lots of separate colour adjustments. Additional processing channels may be called in and at least two channels used simultaneously to carry out the same steps. Subsequently these processors may be released.
Adopting computer processing techniques can lead to great productivity
Desir Jean W.
Eisenzopf Reinhard J.
McDonnell & Boehnen Hulbert & Berghoff
Pandora International Ltd.
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