Abstract: A shutter operation state monitoring method performed in a thermal imaging camera includes, controlling a shutter of the thermal imaging camera to be closed, capturing a first thermal image, calculating a correction offset value for the first thermal image, controlling the shutter to be opened, capturing a second thermal image, applying the correction offset value to the second thermal image, measuring a sound with a microphone when controlling the shutter to be closed and/or when controlling the shutter to be opened, determining whether the measured sound matches an operation sound of the shutter, and outputting an alarm indicating malfunction of the shutter if the measured sound does not match the operation sound.

Abstract: A method and an apparatus for identifying the type of an optical recording medium are provided. The method includes detecting a surface reflected signal SS and a writable-surface reflected signal SR of an optical recording medium while performing a focus search using a first optical system, counting a time difference DTS between a high peak and a low peak of the surface reflected signal SS, counting a time difference DTR between the high peak of the surface reflected signal and a high peak of the writable-surface reflected signal SR, obtaining DT by substituting DTR and DTS into the following equation: DT = ( DT R ) a ( DT S ) b ? ? ( a - b ? 1 2 ) and comparing DT with a reference time T, and driving the first optical system if DT is greater than T and driving a second optical system if DT is not greater than T.

Abstract: An automatic power control (APC) apparatus reducing time necessary for stabilizing an APC circuit at the initial stage of automatic power control of a disc drive is provided. The APC circuit is designed such that a voltage of a predetermined percent of an expected output voltage is previously added to an APC output voltage of the APC circuit of a laser diode, thereby greatly reducing a stabilizing time necessary for stabilizing an APC output voltage at an initial stage in a write or read mode. Therefore, the loss of data in a high speed write or read mode can be reduced. Particularly, the loss of data in a high speed write mode can be greatly reduced.

Abstract: A method of controlling a recording operation for an optical disc recording apparatus classifies a defect in a disc based on an extent to which the defect has an influence on the recording operation and controls the recording operation therewith. The defect is classified into a first category, indicating that data based on a length thereof, is recordable and a second category indicating that the data is not reproducible even though the data is recordable. If the defect is detected, the data is recorded while a servo unit maintains a servo-tracking by a previous servo control value and a defect type is determined. If the defect corresponds to the first category, the data is assumed to be recorded in a defect region and recording data is continued. If the defect corresponds to the second category, the data recorded in the defect region is recorded in another region.

Abstract: A method and an apparatus for identifying the type of an optical recording medium are provided.

Abstract: A method for controlling the speed of a sled motor for an optical disk drive, wherein the sled motor is first driven according to a predetermined target velocity profile stored in a microcomputer. Then, a frequency of a sinusoidal wave output by a Hall-effect sensor is detected and it is determined whether the frequency of the sinusoidal wave is greater or smaller than a predetermined value. The target speed is incremented by a predetermined amount when the frequency of the sinusoidal wave is greater than the predetermined value, and is decremented by the predetermined amount when the frequency of the sinusoidal wave is smaller than the predetermined value.

Abstract: An automatic power control (APC) apparatus reducing time necessary for stabilizing an APC circuit at the initial stage of automatic power control of a disc drive is provided. The APC circuit is designed such that a voltage of a predetermined percent of an expected output voltage is previously added to an APC output voltage of the APC circuit of a laser diode, thereby greatly reducing a stabilizing time necessary for stabilizing an APC output voltage at an initial stage in a write or read mode . Therefore, the loss of data in a high speed write or read mode can be reduced. Particularly, the loss of data in a high speed write mode can be greatly reduced.

Abstract: A disk calibration and search method in a disk drive is provided, in which, after an initialization step, a pickup is jumped to a first position and moved radially in a predetermined direction in response to pulses generated by a frequency generator. During this radial movement the number of tracks crossed are counted. The counting is continued until a predetermined number of the pulses generated by the frequency generator have been generated. A calculated frequency generator track number is then obtained by dividing the counted number of tracks by the predetermined number of pulses generated by the frequency generator, i.e., calculating a unit track number of the disk per a single movement of the pickup, that is, the number of tracks the pickup moves per pulse generated by the frequency generator. The calculated frequency generator track number is stored in memory used to control the frequency generator for jumping the pickup during a search for a target track.

Abstract: A method of discerning an optical disk in a compact disk drive which includes the steps of moving an optical pick-up device to a table of contents (TOC) region of an optical disk to perform a focusing operation for reading data from the optical disk, and discerning whether an optical disk is loaded on a turntable of the compact disk drive. When the optical disk is loaded in the compact disk drive, the loaded optical disk is rotatably driven by a spindle motor. The time necessary for the rotating speed of the optical disk to reach a predetermined speed is counted, and the counted time is then compared with a predetermined time to determine whether the optical disk is one of a first type having, for example, a eight centimeters diameter and a second type having, for example, a twelve centimeters diameter. If the counted time is less than the predetermined time, the loaded optical disk is determined as a eight centimeters disk. If, on the other hand, the counted time is not less than the predetermined time, i.e.

Abstract: A disk calibration and search method in a disk drive is provided, in which, after an initialization step, a pickup is jumped to a first position and moved radially in a predetermined direction in response to pulses generated by a frequency generator. During this radial movement the number of tracks crossed are is counted. The counting is continued until a predetermined number of the pulses generated by the frequency generator have been generated. A calculated frequency generator track number is then obtained by dividing the counted number of tracks by the predetermined number of pulses generated by the frequency generator, i.e., calculating a unit track number of the disk per a single movement of the pickup, that is, the number of tracks the pickup moves per pulse generated by the frequency generator. The calculated frequency generator track number is stored in memory used to control the frequency generator for jumping the pickup during a search for a target track.