Abstract: Audio-centered information is stored on a unitary medium by a Table-of-Contents (TOC) mechanism for specifying an actual configuration of various audio items on the medium. In addition to the TOC mechanism a file-based access mechanism to the information is assigned through a ROOT directory that contains a highest level TOC directory pointing at various audio items.

Abstract: A transmitter is disclosed for transmitting a digital information signal via a transmission medium. The digital information signal can be divided into one or more sub-signals. Each sub-signal is transmitted as a non-encoded or as an encoded signal. In which way the sub-signal is transmitted depends on the compression that can be achieved by the encoder. If the compression is low the sub-signal is transmitted in non-encoded form. For the receiver an identification is added to the composite signal to be transmitted. A first component of the identification signal indicates if one or more sub-signals are transmitted in encoded form. A second component of the identification signal indicates for each sub-signal whether it appears in encoded or non-encoded form in the composite signal. The invention provides a composite signal with a minimal number of bits.

Abstract: A method of embedding an additional layer of error correction into an error correcting code, where information is encoded into code words that are arranged in columns of a code block. The method includes reducing the length of each row of the code block by adding row symbols together according to a predetermined adding rule resulting in a reduced code block; encoding the shortened rows of the reduced code block using a horizontal error correcting code to obtain horizontal parities; and embedding the horizontal parities as additional layer in the error correcting code.

Abstract: A method and a recording device for formatting arid recording on a multi-layer phase-change type optical disc include recording areas on first and second layers of the optical disc according to a predefined sequence, so that an area of the first layer where an incident radiation beam passes through is always fully written or fully empty when recording on the second layer.

Abstract: An electronic circuit comprising means (CMNS) for controlling a current (IL) through a coil (L) for the generation of a magnetic field (H). The means (CMNS) comprise means (DMNS) for the determination of a parameter which is a measure for the value of the resistance (RL) of the coil (L). During operation the maximum absolute value of the current (IL) is decreased when the parameter exceeds a certain limit.

Abstract: A method of recording an encoded bit stream, the encoded bit stream representing a plurality of video objects comprising a sequence of cells together constituting a part of an MPEG2 Program Stream, on a disc like record carrier, such as an optical disc. The method comprising recording video objects comprising a sequence of contiguously recorded cells, each cell comprising a unique cell identification number within a video object, recording a playback sequence of cells defining a playable program chain of cells, wherein the sequence comprises references to the cell identification numbers and recording navigation data within the cells comprising an end time of presentation of the corresponding video object. The method further comprises recording at the end of a video object a dummy cell that is not being referenced by a playback sequence.

Abstract: An optical scanning device for scanning an optical record carrier comprising an information layer. Crosstalk cancellation is provided using a phase modulating element (40, 140) for generating a non-rotationally-symmetric phase profile in a subsidiary radiation beam. The phase profile varies with an azimuthal angle measured about the optical axis of the beam portion, the phase profile varying such that successively different phases are introduced in at least five locations which are each at successive azimuthal angles (?1, ?2, ?N) and each at a given radial distance from the optical axis, wherein the phase profile is such that the phases introduced, when taken in modulo 2? form, successively cycle through 0 to 2? at least twice, whereby the subsidiary beam spot is provided with an intensity distribution on the information layer which overlaps that of the side-lobe of the main beam spot.

Abstract: An optical scanning device (1) is for scanning two information layers (2, 2?) with two radiation beams (4) in two operating modes. It comprises a radiation source (7) for emitting the two radiation beams, an objective lens system (8) for converging the two beams on the positions of the two information layers, and a phase structure (24) having an optical axis (19) and including a central part (P1) and at least one marginal part (P2) for forming a non-periodic stepped profile in the radial direction. One (P2) of said central and marginal parts (P1, P2) includes at least two segments (AS2,1, AS2,2) having two different step heights (h2,1, h2,2), respectively, for introducing in said first operating mode two wavefront modifications W2,1,1? and W2,2,1?, respectively, and in said second operating mode two wavefront modifications W2,1,2? and W2,2,2?, respectively, where the difference (w2,1,2+?W2,2,2)?(?W2,1,1+?W2,2,1?) is asymmetric.

Abstract: A device reads an information carrier that carries identification and user information. The identification information is arranged so as to be spread over the information carrier and includes data and parities. The device includes a reader for reading the information from the information carrier and error corrector correcting errors in the information. The device further includes an organizer for organizing the information in such a way that both the identification and user information can be processed by the error corrector.

Abstract: In a motion detection system, filters are applied to a series of digital images in order to determine whether changes in the properties of pixels between the current image and a reference model are due to motion of objects or to changes in lighting. The filter may be based on scaled differences between a current image and a reference model. The type of surface may be determined based on optical properties of the surface and then only the best filter for that type of surface is applied. Alternately, multiple filters may all be applied and the results combined. The processing may be reduced using a background model to determine which pixels are in the background and which are in the foreground and then only applying the filter to the foreground pixels.

Abstract: The invention relates to a method of storing a number of data bits of a secondary channel (30) in the frame of a main channel (20) and to a method of decoding a stream of bits relating to a secondary channel (30) embedded in the frames of a main channel (20) into a stream of data bits (62). In order to enable a certain synchronization and to guarantee a fixed amount of storage capacity in the secondary channel as well as to be able to correct deletions or insertions of bits in the secondary channel it is proposed according to the invention to form a secondary frame (11) having a fixed number of frame bits, to fill a fixed part of the secondary frame (11) with data bits (113), an end-bit (114) set to a first bit-value and, if necessary, with filling bits (115) set to a second bit-value, to encode the secondary frame (11) producing encoded data bits (113) and parity bits (112), which are finally embedded in the frame of the main channel (20).

Abstract: An optical scanning device (1) for scanning three information layer (2, 2?, 2?) with three respective radiation beams (4, 4?, 4?) having three respective wavelengths (?1, ?2, ?3) and polarizations (p1, p2, p3). The three wavelengths differ from each other. At least one of the three polarizations differs from the others. The device comprises a diffractive part (24) including a pattern of pattern elements which have one stepped profile for forming three diffracted beams (15, 15?, 15?) from the three radiation beams, the part comprising birefringent material, sensitive to the three polarizations. The stepped profile is designed such that the heights (hj) of the steps of a pattern element introduce phase changes that equal at least two different multiples of 2? for one (?1) of the three wavelengths and equal at least two different phase changes modulo 2? for one (?2) of the two other wavelengths.

Abstract: The invention relates to a method of manufacturing a replica, which method comprises the provision of a polymerizable resin composition between a front mold having a pre-shaped surface and a back mold having a pre-shaped surface, carrying out a curing treatment and removing the replica thus manufactured from the molds. The invention further relates to a replica obtained by carrying out a UV light-initiated cationic polymerization.

Abstract: A optical scanning device (1) for scanning an information layer (2) with a radiation beam (25) in a writing mode and a reading mode comprises a radiation source (7) for emitting the beam and an objective lens (10) for converging the beam so as to form a scanning spot (19) in the information layer. The device also includes a scanning spot power switch (20) for switching the size of the cross-section of the beam between a first size at the writing mode and a second, larger size at the reading mode so as to switch the rim intensity of the beam between a first intensity level (Irim,writing) at the writing mode and a second, higher intensity level (Irim,reading) at the reading mode, thereby switching the light power of the scanning spot between a first power level (Pwriting) at the writing mode and a second, lower power level (Preading) at the reading mode.

Abstract: In a zoom lens (30) comprising, from the object side to the image side, a front lens group (12) and a controllable lens group (24), the controllable lens group comprises two lens elements (25, 26) having different dispersions and being movable with respect to each other so as to perform a focusing action. One of the lens elements corrects for the dispersion of the zoom lens. Preferably, the zoom lens comprises at least one folding mirror.

Abstract: The invention relates to a scanning apparatus for scanning information in an information carrier (16) comprising a plurality of layers for storing data on a material capable of generating an excited radiation when interacting with an exciting beam (13) produced by an exciting source (11). The scanning apparatus comprises an objective lens (15) for projecting the exciting beam in a layer of the carrier and collecting the excited radiation. The scanning apparatus also comprises a detector unit (19) for detecting the excited radiation collected on the objective lens. According to the invention, the exciting beam has a numerical aperture lower than the lens numerical aperture.

Abstract: A recording apparatus for recording data on a rewritable optical recording medium includes a read/write head for reading and recording data, an error corrector for finding and correcting errors in the recorded data read, and a controller for controlling the recording and reading of the data. The recording apparatus is capable of performing fast and efficient examination of formatted recording medium in order to adapt a data recording strategy, so as to increase the efficiency of writing operations.

Abstract: An optical head for use in the scanning of a record carrier, the record carrier having data stored on data tracks therein on a plurality of information layers (3, 4) at a plurality of depths within the record carrier. The optical head comprises: a movable optical element (16) arranged in an optical path to act upon a first radiation beam (12) and a second radiation beam (14) to provide the beams with a different displacement perpendicular to the optical path; and a lens system for focusing said first beam (12) at a first focal point (A) on a first information layer (3) of the record carrier and the focusing of the second beam (14) at a second different focal point (B) on a second information layer (4), wherein a spacing, transverse to the data tracks, between said first and second focal points (A, B) is controllable by varying the configuration of the movable optical element.

Abstract: An acoustic based pointing device and a system and method for using the pointing device to move a cursor on a display screen of a display device. The pointing device comprises an acoustic source that generates and propagates an acoustic signal that is detected by four microphones M1, M2, M3, and M4 and is then converted into corresponding periodic electrical signals S1, S2, S3, and S4. The position vector P0 of the acoustic source is calculated by solving triangulation equations that depend on phase-shift time delays between S1 and Sj for j=1, 2, and 3. A position vector PC is calculated from P0 using a scale vector that relates a change in position of the cursor to a change in position of the acoustic source. Then the cursor is moved to a position PC associated with the position vector PC.

Abstract: How to record and play back data at a high line density. A DSV control bit determining/inserting unit 11 inserts DSV control bits for execution of DSV control into an input data string and outputs the data string including the DSV control bits to a modulation unit 12. The modulation unit 12 converts the data string with a basic data length of 2 bits into variable length code with a basic code length of 3 bits in accordance with a conversion table and outputs the code resulting from the conversion to a NRZI encoding unit 13. The conversion table used by the modulation unit 12 includes substitution codes for limiting the number of consecutive appearances of a minimum run to a predetermined value and substitution codes for keeping a run length limit.