Canon Kabushiki Kaisha

Seiichiro Satomura

Katuya Yamazaki

Takashi Suzuki

Mitsuru Kurita

Hidekazu Shimomura

Kazuyoshi Ishii

Kazuhiko Matsuoka

Takeshi Yamawaki

Toshio Iwaya

Masahide Kotera

Fumiyuki Mikami

Kano Takeshita

This invention relates to an image reading apparatus which eliminates color misregistration upon reading in the sub-scanning direction, which occurs due to different afterglow or persistence characteristics of the respective colors of a light source upon executing the light quantity control of the light source for illuminating an original. Since the light quantity control of the light source is divisionally done a plurality of times in one accumulation period of a solid-state image sensing element, any deviation of the center of gravity in the quantity of light from the center C of one accumulation period can be minimized, and the color misregistration can be eliminated remarkably.

Image reading apparatus and method

Disclosed are methods of determining and recording a synchronous signal pattern on a medium and also an information recording/reproducing device thereof. The method of determining an optimum synchronous signal pattern includes detecting correlation properties of a VFO pattern and a synchronous signal pattern with a matching filter by inputting the respective samples of the patterns to the matching filter; and determining the sample exhibiting an excellent correlation property as the synchronous signal pattern among the samples. The information recording method includes forming information by sequencing the VFO pattern, the determined synchronous signal pattern and (2, 7)-modulated data; and recording the information on a recording medium. The information recording/reproducing device includes a device for recording, on a recording medium, the information configured by sequencing the VFO pattern, the synchronous signal pattern for identifying the head of information and (2, 7)-modulated data; and a device for reproducing the information. The VFO pattern consists of a repetitive pattern of '0000' or '100' or '010', and the synchronous signal pattern is a binary signal pattern.

Method of determining a syschronous signal pattern and method of and

An optical head is used in a magnetic field modulation type magnetooptical recording/reproducing apparatus. The optical head includes a device for irradiating a magnetooptical record medium with a light beam, a separating device for separating a reflected light beam from the magnetooptical record medium into two beams to be projected onto a single plane, a single photodetector provided with two two-divided light receiving portions for respectively receiving the two beams, and a single convex lens element for forming images of the two beams as light spots on the single photodetector.

Optical head and optical information reading apparatus

A method of recording new information on a recording medium on which information was previously recorded is performed as follows. The new information is stored in a memory. The new information is overwritten onto a portion of the recording medium where the old information was recorded by scanning the recording medium with a light beam. A signal including both the old information and the new information is reproduced from the light beam reflected by the recording medium simultaneously with the overwriting. A signal component corresponding to the new information is extracted from the reproduced signal. The extracted signal component is compared with the new information stored in the memory. It is determined on the basis of a comparison result whether or not the recording has been correctly performed.

Information recording method and apparatus for determining whether

A method of recording data in a recording medium is performed by using an RLL (Run Length Limited) Code represented by (d,k,m,n)=(1,7,2,3). When it is assumed that X is an indeterminate bit which is determined by the data, a one-byte resync signal with a pattern represented by 'X01000000001' is periodically inserted into the data. Then, the data into which the resync signal is inserted is recorded on the recording medium. A method of recording data in a recording medium in accordance with NRZI (Non Return to Zero Inverted) recording is performed by using an RLL code represented by (d,k,m,n)=(1,7,2,3). When it is assumed that X is an indeterminate bit which is determined by the data, one of one-byte resync signals represented by patterns 'X01000000001' and 'X01000000101' is selected such that a DSV (Digital Sum Value) of a coded signal is decreased. The selected resync signal is periodically inserted into the data. Then, the data into which the resync signal is inserted is recorded on the recording medium.

Data recording method and data recording apparatus using a digital sum

An information reproducing apparatus according to the present invention is capable of overcoming a problem of impossibility in data reproduction which takes place due to a deletion of a SYNC signal or a RESYNC signal or generation of a false signal. If the above-described signal has been deleted, a normal RESYNC position estimation pulse, estimated from the previous signal, is used in place of the deleted signal. As for the false signal, the structure is arranged in such a manner that only one signal is generated by arranging the RESYNC window circuit or the delay circuit and that the generated signal does not adversely influence the detection of a next RESYNC signal. Therefore, the above-described requirement is achieved by adding of a simple structure.

Circuit for detecting a synchronous signal included in an information

A method and apparatus for detecting pulse signals corresponding to marks from a recording medium on which the marks are periodically recorded. The recording medium is scanned with a reproducing transducer and a reproduction signal (including the pulse signals) is read out. A gate signal with a predetermined width is generated on the basis of the pulse signal which has been detected at k period before the pulse signal to be detected, where k is an integer more than 1. If the pulse signal before k period is missing, the gate signal with a predetermined width is generated on the basis of the pulse signal which has been detected at k+1 period before. Only the pulse signal existing within the period during which the gate signal is output is extracted from the reproduction signal.

Method and apparatus for detecting pulse signal for generating clock

A method and apparatus is provided for reproducing data using a disc-like recording medium having a plurality of zones divided radially thereof. Different frequencies are set for the zones each of which includes a plurality of data blocks disposed in a predetermined order. A signal with the set frequency is recorded on the data blocks in the respective zone. The data blocks are scanned by a head to read out the recorded signal while moving the head radially over the recording medium. A clock generating circuit generates a clock signal with a frequency set for the zone to which the data block being scanned by the head belongs. The data is reproduced from the signal read out by the head using a reproduction circuit, on the basis of the clock signal. When the head reads out the signals over two continuous zones, the head position of the last data block of the zone from which the signals are read out earlier is detected and a detection signal is outputted. In response to the detection signal, a control circuit instructs the clock generating circuit to change the frequency of the clock signal.

Data recording and/or reproducing method and apparatus

An information processing apparatus having the function of reproducing digital information recorded on a recording medium has binarizing circuit for transforming a reproduction signal read from the recording medium into a binary signal, circuit for making from the binary signal a bit synchronous signal for use when the binary signal is demodulated, circuit for detecting the inverted portion of the binary signal by a periodical window of a predetermined period and producing a synchronous binary signal synchronized with the bit synchronous signal in accordance with the result of the detection, demodulating circuit for demodulating the digital information on the recording medium on the basis of the synchronous binary signal, and circuit for varying the period of the window in conformity with the situation. According to the above method, any small defect likely to develop into an error in the future is effectively detected to thereby obviate such a situation that the detection of a synchronous pattern becomes impossible or the reproduction of data becomes impossible.

Information processing apparatus

There is provided a digital signal reproducing apparatus comprising: a binarization circuit to binarize a signal which was read out of a recording medium or a transmitted signal; first and second pulse generators to generate pulses which are respectively synchronized with leading and trailing edges of a binary signal which was binarized by the binarization circuit; and first and second signal generators to generate first and second position signals indicative of the positions of the leading and trailing edges synchronously with the first and second sync pulses which are generated from the first and second pulse, generators. The binary signal is a signal of the NRZI coding method. Each pulse generator has a PLL circuit. With the apparatus, the signal can be accurately reproduced irrespective of the recording density by compensating the phase difference between the leading and trailing edges of the binary signal.

Digital signal reproducing apparatus

In method and apparatus for recording information, an information signal to be recorded is encoded, the enclosed signal is stored in a memory and also recorded on a recording medium, the signal recorded on the medium is read, and the read signal is compared with the signal stored in the memory to detect a recording error.

Method and apparatus for verifying a signal recorded in an encoded form

An information data recovering apparatus which recovers the original information data from transmitted data of (2, 7, 1, 2, 3) Run Length Limited code to which the original data is converted. When 7 successive '0'-bits of a train of transmitted data are input to the apparatus, bit data at a position spaced by a predetermined number of bits from that time is converted as the head of original data and the input transmitted data subsequent to the bit data is converted to the original data.

Information data recovering apparatus

An apparatus for reading a microfilmed image to obtain digital image signal, in which the level of quantizing is determined by measuring the density of image and of background.

Apparatus for reading a film image with controllable illumination and

In an auto-focus apparatus of the invention, an image sensor (e.g., a CCD) produces an image signal corresponding to an image on a microfilm. The image signal from the image sensor is encoded to a binary image signal by a binary encoding circuit. Alternation points (i.e., leading or trailing edges) of the binary image signal are counted by a counter. A system controller fetches count values from the counter, and detects an image position corresponding to a maximum count value. The system controller causes a lens driving circuit to move an imaging lens to the detected image position.

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Yokohama, Japan

Seiichiro Satomura