Abstract: A holographic recoding medium is provided, having holographic pages. Each page has reference mark (RM) placement areas at fixed locations for placing RM patterns. The reference marks are used to calibrate data images of data areas each of which is enclosed by at least three RM regions. Hidden information of the medium is stored by an specific encoded pattern based on existence, types and arrangements of the RM marks.

Abstract: An asymmetry compensator for a partial response maximum likelihood (PRML) decoder, which is utilized to remove and eliminate the asymmetric component of the regenerating signal read from the optical recording medium, thereby effectively solving the problem of the asymmetry of the optical disk regenerating signal. The compensator includes an offset controller and a gain controller. The offset controller determines the central level of the regenerating signal thus to adjust the offset of the regenerating signal while the gain controller is arranged to adjust the gain of the regenerating signal.

Abstract: A method and an apparatus for detecting code of a holographic data page are provided. First, image information of at least one special pattern in the holographic data page is captured, and the captured image information is integrated into a characteristic symbol (CS) of the holographic data page. Then, the CS of the holographic data page is compared with a plurality of predetermined characteristic symbols (PCSs) to obtain a similarity between the CS and each of the PCSs. Thereafter, the PCS having the highest similarity to the CS is selected as the code information of the holographic data page.

Abstract: A holographic data storing method includes the steps of: encoding original data to generate holographic data according to a codeword to symbol relation; and recording a hologram corresponding to the holographic data onto a holographic storage medium. In the codeword to symbol relation, a plurality of sample symbols corresponds to a plurality of codewords. Each of the sample symbols corresponds to a pattern having N*N pixels. There are M bright pixels in the N*N pixels, wherein N and M are positive integers and M is smaller than N*N. A hamming distance of the sample symbols is greater than or equal to 4, and a two-dimensional run-length of the sample symbols is greater than or equal to 2.

Abstract: A hologram media reading apparatus including a reference light source, a stop with gray level aperture, and an optical sensor is provided. The reference light source is disposed on one side of a hologram medium, and capable of emitting a reference light beam. The reference light beam is transmitted to the hologram medium. The stop with gray level aperture and the reference light source are disposed on the same side or opposite sides of the hologram medium. The stop with gray level aperture has a light transmissive region, an opaque region, and a transmittance gradually varying region. The opaque region surrounds the light transmissive region. The transmittance gradually varying region surrounds the light transmissive region. A part of the reference beam from the hologram medium passes through the stop with gray level aperture and is transmitted to the optical sensor.

Abstract: A holographic recoding medium is provided, having holographic pages. Each page has reference mark (RM) placement areas at fixed locations for placing RM patterns. The reference marks are used to calibrate data images of data areas each of which is enclosed by at least three RM regions. Hidden information of the medium is stored by an specific encoded pattern based on existence, types and arrangements of the RM marks.

Abstract: An asymmetry compensator for a partial response maximum likelihood (PRML) decoder, which is utilized to remove and eliminate the asymmetric component of the regenerating signal read from the optical recording medium, thereby effectively solving the problem of the asymmetry of the optical disk regenerating signal. The compensator includes an offset controller and a gain controller. The offset controller determines the central level of the regenerating signal thus to adjust the offset of the regenerating signal while the gain controller is arranged to adjust the gain of the regenerating signal.

Abstract: A method for driving an LED display. The LED display has an array composed of rows and columns of pixels, wherein each of the pixels comprises an LED. The method comprises the steps of generating a plurality of scan signals, each of which is fed to a corresponding row, wherein one of the rows is selected when a pulse occurs in the corresponding scan signal, generating a plurality of data signals, each of which turns on or off the LED of one of the pixels in the selected row of the array, and adjusting a width of the pulse in the scan signal fed to the selected row according to the number of turned-on pixels in the selected row.