Nec Corporation

Shiro Fujihara

Hirotaka Nakano

Kazuhito Takai

Yasuhiko Okuhara

Fumihiro Okazaki

Toshihiro Masumoto

In a system for recording digital contents compressed and delivered by the MPEG (Moving Picture Experts Group) standard, in decoding the contents, even a DCT coefficient of the digital contents is required in a discrete cosine transform (DCT) unit, according to the attribute information belonging to the digital contents, of the DCT coefficients within a block, some AC coefficients remain and the other AC coefficients are turned to 0, and the obtained DCT coefficients are again encoded so to create stream data for recording.

Copy controlling method and system of digital contents

An image data processing device allowing both of user side and provider side to obtain benefits, leading to market expansion, is disclosed. When an image content is copied, an additional watermark is inserted into the copied image content. When an additional watermark is detected from input image content data, a further copy of the image content is prohibited.

Image data protection technique

In a communication system, a transmitting device transmits an image datum to which a specified datum is inserted as an electronic watermark by watermark insertion technique. The image datum represents an image. The specified datum represents a specified process for a receiving apparatus for receiving the image datum. In the receiving apparatus, a processing arrangement is responsive to the image datum and processes the specified datum to execute the specified process. A producing arrangement is responsive to the image data and produce the image.

Receiving apparatus, transmitting apparatus, and communication system which utilize a watermark insertion technique

An encoder, which comprises a means,for embedding a specific electronic mark data in a characteristic part of an image converted to a spatial frequency area, a quantizing means,for quantizing the spatial frequency area data in which the electronic mark data is embedded and a variable length encoder,for variable length coding the quantizer output, outputs compression coded digital image data. A decoder comprises a variable length decoder,and reverse quantizer,for restoring compression encoded digital image data to spatial frequency area data, means,for detecting the electronic mark data from the restored data, and detection display means,for displaying the detection result.

Image data processor

In a card type recording medium containing a data area where data containing ID information of a holder are recorded, and an image area where image data are recorded, in the image area are recorded second image data which are generated by transforming first image data specifying the holder to frequency-area data, adding the transformed frequency-area data with the ID information and inversely transforming the added data to image signals.

Card recording medium, certifying method and apparatus for the recording

The barrel shifter of the present invention comprises a latch circuit of (m+n) bit, a register for indicating an effective bit length retained in the latch circuit, a selector for connecting the variable length code of maximum n bit with the latch circuit and a counting circuit for counting shifting number. In this invention, the latch circuit is divided by k bit, and the selector is controlled so as to shift bits of difference between the value lastly shifted and the value of the register, and data is retained at the latch circuit. When the value of register exceeds m, the selector outputs m bits to the latch circuit and the data at the latch circuit is shifted m bits.

Barrel shifter

A method and an apparatus for compression-coding of thinned-out motion picture frame are described. A received motion picture data is subject to DCT (discrete cosine transformation). The DCT coefficients are stored in a frame memory, and also accumulated over a frame of the received motion picture concerned. The accumulated value is used as a predicted code amount of the received frame concerned. The DCT coefficients stored in the frame memory are read and quantized two times. A first quantization step for the first quantization is selected based on a reference code amount, the accumulated value and the final code amount (described below) of the motion picture frame received immediately before the frame concerned. After the first quantization, the quantized DCT coefficients are variable-length-coded to produce a first series of codes of a first code amount. A coarse quantization step is selected as a second quantization step for second quantization when the first code amount is larger than the reference code amount, and when the first code amount is vice versa, a fine quantization step is selected. The DCT coefficients read for the second time are quantized according to the second quantization step, variable-length-coded to produce a second series of codes of a second code amount. Of the two code amounts, the code amount closer to the reference code amount is determined as a final code amount and the series of codes having the final code amount is outputted as variable-length-codes of the motion picture frame concerned.

Growing community of inventors

Tokyo, Japan

Shiro Fujihara