Independent Broadcasting Authority

Rank Cintel Limited

Other

Digital Projection Limited

John L Baldwin

John G Ive

Robert A Bellis

Brian Eckersley

Peter W Blaxtan

Terence E Corbyn

A display device includes a deformable mirror device wherein grey scales are displayed using a time division modulation process in which the times or sub-frame periods for which each mirror within the deformable mirror array is switched on. The device includes a selection means for ordering selected sub-frame periods or divided sub-frame periods such that the light directed from each mirror is substantially temporally balanced during each frame period of the display device and/or between consecutive frame periods.

Display device using time division modulation to display grey scale

In non-linear digital video processing, high frequency components resulting from the non-linearity may appear as spurious low frequencies due to mirror image spectral reflection in the sampling frequency fs. The non-linear circuit may be a gamma corrector (35). The effect of the alias components is reduced by the use of a modifier circuit (50) before the gamma corrector, and a corresponding equalizer circuit (52) after it. The modifier attenuates the high frequency signal components, especially in the region fs/4 to fs/2. The equalizer substantially reinstates the overall frequency response. Both modifier and equalizer may be transversal filters (FIGS. 5 to 8) which, more generally, may be one dimensional or two dimensional (FIGS. 9 and 10). The system is also particularly relevant to progressively scanned sources; including telecine.

Method and apparatus for reducing the effect of alias components

A video signal is recorded on unexposed cinematographic film by shining light from a light source onto a deformable mirror device (DMD), which comprises a micro-mechanical array of electronically-addressable mirror elements, the elements corresponding to individual pixels. The elements of the DMD are controlled or modulated in response to the video signal. Light is selectively reflected by the DMD onto an image plane containing the film such that the light reaching the film is representative of the video signal.

Recording video signals on cinematographic film using a deformable

A sampled input signal, e.g. a video signal, is processed to provide output signals appropriate for positions between input samples by interpolating between the input samples using an interpolating transversal filter (110) and filtering the interpolated signal with a second filter (150) the gain of which increases with increasing frequency. The coefficients of the interpolating transversal filter are chosen so as simultaneously to compensate the frequency response of the second filter and to provide a desired position offset of the output samples with respect to the input samples. The interpolation and filtering steps may be reversed in order. Surprisingly the interpolation is improved in quality when it incorporates a de-emphasis operation in this way. The sampling may be the sampling achieved by the video signal line structure. A non-linear circuit (140) such as a gamma corrector may be interposed between the interpolator and the equalizer. The system can in particular be used to process the video output of a telecine, or to process digital audio signals.

Method and apparatus for signal processing by interpolation and

A continuous-motion line-array telecine has a solid-state sensor comprising linear array sensor elements (101, 201, 301). For multi-standard operation compensation is provided for vertical misregistration due to different linear array sensor positions as seen at the sensor plane. The compensation is provided by relative delays (160, 260, 360) corresponding to vertical scan shifts of integral numbers of lines, and vertical interpolation circuits (110, 210, 310) for interpolating between lines for compensating any misregistration equivalent to any residual non-integral vertical scan spacing.

Continuous-motion line-assembly telecine with misregistration correction

A continuous-motion line-array telecine images the film image onto three linear array sensors having respective color filters. Vertical scanning is provided by the continuous motion of the film. The sensors can be spaced by an amount equivalent to a given number of line scans for one film and television format combination. To accommodate other formats, a cylindrical lens pair is selectively included, which provides a desired magnification in the vertical direction but not the horizontal direction. The sensor spacing does not then need to be changed and the sensors can be made as an integral device, so that they can be constructed closer together and are likely to have more similar characteristics.

Continuous-motion line-array telecine

Method and apparatus for processing digital signals prior to recording

Digital television tape recording

Apparatus is disclosed for use in a digital signal transmission or recording system, particularly for video signals where, as is customary, the number of digital signals (i.e., digital words) is reduced (for example, by a factor of 2) prior to transmission or recording. The apparatus is operable to determine when a digital word fed to an input filter has a characteristic similar to that of a filtered word so that such a word can bypass the input filter and be transmitted or recorded without further filtering. This is achieved by monitoring the words input to the input filter and then operating a bypass around the input filter when the monitoring circuit detects that an input word has a characteristic similar to a filtered word.

Processing of digital signals

Apparatus for decreasing the d.c. component of digital signals derived from an analogue signal which may be a television video or audio signal, comprises analogue to digital converter means for producing digital words corresponding to samples of the analogue signal, a memory device for subjecting the words to a specific code conversion and circuitry for combining the coded words together in groups of two words with one of the words ones complemented and preferably partially interleaved with the other of the words of each group. The apparatus is applicable to use for both the recording of color T.V. video signals as well as for the transmission of such signals.

Digital recording apparatus

Digital recording and reproducing apparatus is disclosed for recording digital signals in such a manner as to conceal errors contained therein, including a write address generator for storing incoming digital signals in a first sequence in a memory, and a read address generator for causing the signals to be read out from the memory in a second sequence different from the first sequence. A control device selectively connects the write address generator and the read address generator sequentially to the memory, whereby the digital signals read out from the memory may be recorded on a recording medium.

Recording of digital signals

A method and apparatus are disclosed for assembling digital data representing a T. V. picture, including the steps of producing digital words representing a line of video, producing a digital code indicative of each line of video, producing a digital code indicative of the field containing the line, combining the digital codes and the digital words for each line of video, storing the digital words line-by-line until a number of lines at least equal in number to the number of lines in a field has been stored, and reading out the digital words. One advantage afforded by the invention is that for fast winding during editing, the stored field of video can be made up of lines derived from a number of different fields, thereby not only reducing the amount of storage required, but also speeding up the process.

Digital television system and method

A method of recording digital video signals, particularly color television signals, in such a manner that type drop outs and other errors can be corrected, comprises arranging the words in a manner on a recording medium such that the information used to replace an error comes from a part of the recording medium which is statistically well separated from the error. This is achieved using a plurality of recording tracks. Apparatus for carrying out the method comprises a plurality of shift registers for storing the digital signals, and means for reading out the signals in the desired manner. The preferred method of error correction is to arrange signals from the same line of video raster.

Recording digital signals

Digital delay apparatus for variable delay uses a shift register fixed delay driving a random access memory variable delay. A variable modulus counter controls the read-write addressing, whereby the difference between addresses sets the variable delay of the random access memory. The random access memory capacity is small relative to the shift register for increased efficiency.

Delay circuits

A circuit for monitoring digital data comprises a shift register for receiving the data to be monitored, the outputs of the shift register being fed either directly to the inputs of memory devices or via controllable gates. The memories are programmed to detect the number of logical `ones` present in the shift register, and the detected number is compared with a reference to determine whether the data should be accepted or rejected. In one mode of operation, the controllable gates alter the inputs to the memories such that they are all the same when the correct data is in the shift register. In another mode of operation, the gates supply the memories with unaltered data and the circuit can detect errors because the data is coded in such a manner that each block of data should contain the same number of digits and the same number of logical `ones`.

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Eastleigh, United Kingdom

John L Baldwin