Pulse or digital communications – Bandwidth reduction or expansion – Television or motion video signal
Reexamination Certificate
1997-12-16
2001-03-20
Kelley, Chris S. (Department: 2613)
Pulse or digital communications
Bandwidth reduction or expansion
Television or motion video signal
C375S240240
Reexamination Certificate
active
06205179
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a picture reproducing method and apparatus for reproducing a still picture recorded on a recording medium.
2. Description of related Art
In a conventional digital video tape recorder for digital recording/reproducing of video data, one frame of picture signals from an imager or other picture input signals is stored on a random access memory (RAM), in which the one-frame picture data are split into 8 by 8 pixel blocks and shuffled with a pre-set number of blocks as a unit. The resulting data is orthogonal-transformed, such as by discrete cosine transform (DCT), and quantized for compressing the one-frame video data. The compressed video data is framed and deshuffled, that is processed with an operation reversed from shuffling, on the RAM, for restoration to the original data array. An outer parity and an inner parity for error correction are then appended to the resulting data and encoded for recording. The encoded data is then recorded on a video tape.
In the playback system, the playback signals from the video tape are decoded, that is processed with an operation reversed from the encoding, to produce playback data, which is then error-corrected on the RAM using the outer parity and the inner parity, and shuffled. The resulting shuffled data is deframed and dequantized and the resulting dequantized data is inverse-orthogonal-transformed for expanding the one-frame playback data. The expanded one-frame playback data are deshuffled, that is processed with an operation reversed from the shuffling, and deblocked, for reproducing the video data having the original pixel array.
Meanwhile, the picture signals of the standard television system, such as the National Television System Committee (NTSC) system of the Phase Alternation by Line (PAL) system, are interlaced signals. Therefore, if, in the above-described conventional digital video tape recorder, the input picture signals are stored as still pictures in a RAM for shuffling or deshuffling, and the still pictures are directly recorded/reproduced as contiguous frame pictures, the picture portions having a significant amount of motion represent field period deflection on reproduction.
If one of the even-numbered frame and the odd-numbered frame making up an original one frame picture×2 is recorded as one frame for possibly evading the above-mentioned field period deflection, vertical resolution is deteriorated.
If the recording system has a dedicated still picture processor configured for storing one-frame video data in a RAM and the amount of motion within one frame is found so that a picture portion with a small amount of motion is directly outputted as a frame and the picture portion with a significant amount of motion is outputted as repetition of one of the fields, still pictures free of field period deflection can be recorded for reproducing still pictures of high definition by any reproducing device. However, since the dedicated still picture processor and a RAM for storing the video data for processing by this still picture processor need to be provided in the recording system, the circuit scale of the recording system is prohibitively increased.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a picture reproducing method and apparatus for recording/reproducing pictures of high picture quality without the necessity of providing a dedicated still picture processor or a RAM for storing the video data for processing by this still picture processor.
In one aspect, the present invention provides a picture reproducing device for reproducing video signals from a recording medium having orthogonal-transformed coefficient data quantized and recorded thereon, the orthogonal-transformed coefficient data being data orthogonal-transformed on the basis of a transform block having a pre-set number of pixels as a unit, with the pixels being two-dimensionally arrayed as a continuous picture of a frame of video signals. The picture reproducing device includes dequantizing processing means for dequantizing playback signals from a recording medium for generating the orthogonal-transformed coefficient data, and inverse orthogonal transform processing means for inverse orthogonal transforming the orthogonal-transformed coefficient data generated by the dequantizing processing means and for effecting motion detection on the basis of the orthogonal-transformed coefficient data from one transform block to another. The picture reproducing device also includes multiplexing means for replacing the information specifying the results of motion detection for every transform block by the inverse orthogonal transform processing means, memory means for storing one frame of playback video data having multiplexed thereon the information specifying the result of motion detection outputted by the memory means and control means for controlling readout of video data from the memory means so that the playback video data of the transform block detected to be a still picture block is outputted as a frame and so that the playback video data of the transform block detected to be a moving picture block is outputted as a field twice.
Preferably, the multiplexing means replaces the LSB of blue data of a macro-block including a transform block detected to be a moving picture block based on the information specifying the result of motion detection by the information specifying the result of motion detection.
Preferably, the control means generates the control information controlling video data readout from the memory means on the macro-block basis, based on the information specifying the results of motion detection read out from the memory means, the control means controlling readout of the video data from the memory means on the macro-block basis.
In another aspect, the present invention provides a picture reproducing method for producing video signals from a recording medium having orthogonal-transformed coefficient data quantized and recorded thereon, the orthogonal-transformed coefficient data being data orthogonal-transformed on the basis of a transform block having a pre-set number of pixels as a unit, with the pixels being two-dimensionally arrayed as a continuous picture of a frame of video signals. The method includes inverse-orthogonal-transforming orthogonal-transform coefficient data obtained on dequantizng playback signals from the recording medium, effecting motion detection from one transform block to another based on the orthogonal-transform coefficient data, multiplexing the information specifying the results of motion detection on the LSB of the playback picture data for transmitting the information along with the playback picture data and outputting, based on the results of motion detection specified by the LSB of the playback video data, playback picture data of a transform block detected to be a still picture block and playback picture data of a transform block detected to be a moving picture block as a frame and as twice outputted fields, respectively.
With the picture reproducing device of the present invention, in reproducing video signals from a recording medium having quantized and recorded orthogonal transform coefficient data for every orthogonal transform block made up of a pre-set number of blocks two-dimensionally arrayed as a continuous picture of video signals, the playback signals from the recording medium are dequantized by a dequantizer to generate orthogonal transform coefficient data from which playback picture data are generated by the inverse orthogonal transform processor, while motion detection is effected every orthogonal transform block based on the orthogonal transform coefficient data. The resulting motion detection information for every transform block, that is the information specifying whether a given picture is a moving picture or a still picture, is replaced by the LSB of the playback picture data of the corresponding orthogonal transform block by the multiplexing means, and the playback video dat
Komori Kenji
Tauchi Yoichiro
Frommer William S.
Frommer Lawrence & Haug LLP.
Kelley Chris S.
Philippe Gims
Polito Bruno
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