Patent EP0569718A2 successfully refreshed from Google Patents.
EP0569718A2
Expired / Lapsed
EP
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Method and apparatus for reading data
Assignee: Individual
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Filing: 1993-04-13
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Granted: —
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Expires: 2013-04-13
Abstract
Abstract A method of reading data from an optical disk comprises providing means for illuminating the required part of the disk and acquiring the optical image of a plurality of tracks, providing a detector matrix comprising a plurality of detectors, each of the said detectors being capable of producing an output signal which is proportional to the intensity of the light detected by it causing an optical image corresponding to an illuminated area to fall on the said detector matrix, transferring the output signal of the said detector matrix to image processing means, determining position coordinates of the track center for each data track, by analyzing the output signal of the said detector matrix, saving in memory means expected track center data, comprising position coordinates of the track center located by the said analysis of the output signal, and if an actually detected track center is shifted with respect to the said expected track center, electronically moving the track center position. Furthermore, the invention comprises an apparatus for the embodiment of the above mentioned method.
Inventors
- 👤 Amir Alon
- 👤 Shlomo Shapira
- 👤 Itzhak Katz
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 19:21
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/13; G11B7/131; G11B7/08; G11B7/09; G11B7/0901; G11B7/125; G11B7/127; G11B7/128; G11B7/135; G11B7/1362; G11B7/1384; G11B7/14
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
175 words
A method for reading data from an optical disk, characterized in that it comprises the steps of: 1) providing means for illuminating light the required part of the disk and acquiring the optical image of a plurality of tracks; 2) providing a detector matrix comprising a plurality of detectors, each of the said detectors being capable of producing an output signal which is proportional to the intensity of the light detected by it; 3) causing an optical image corresponding to an illuminated area to fall on the said detector matrix; 4) transferring the output signal of the said detector matrix to image processing means; 5) determining position coordinates of the track centre for each data track, by analyzing the output signal of the said detector matrix; 6) saving in memory means expected track centre data, comprising position coordinates of the track centre located by the said analysis of the output signal; and 7) if an actually detected track center is shifted with respect to the said expected track centre, electronically moving the track centre position.
Claim 2
Dependent Claim
17 words
A method according to claim 1, characterized in that light detected by the detector matrix is non-coherent.
Claim 3
Dependent Claim
20 words
A method according to claim 1 or 2, characterized in that neighbouring tracks are electronically accessed via a multiplexer unit.
Claim 4
Dependent Claim
47 words
A method according to claim 1, characterized in that it further comprises the steps of carrying out a "locking" operation to determine the track centre coordinates, and of using the coordinates of the track centre so found as the first reference value for the expected track centre.
Claim 5
Independent Claim
27 words
A method according to anyone of claims 1 to 4, characterized in that a number of consecutively determined track centre values are memorized, for each track centre.
Claim 6
Independent Claim
108 words
A method of reading data from an optical disk, characterized in that it comprises the steps of: 1) providing means for illuminating the required part of the disk and acquiring the optical image of a plurality of tracks with non-coherent light; 2) providing a detector matrix comprising a plurality of detectors, each of the said detectors being capable of producing an output signal which is proportional to the intensity of the light detected by it; 3) causing an optical image corresponding to a illuminated area to fall on the said detector matrix ; and 4) transferring the output signal of the said detector matrix to image processing means.
Claim 7
Dependent Claim
18 words
A method according to claim 6, characterized in that neighbouring tracks are electronically accessed via a multiplexer unit.
Claim 8
Dependent Claim
86 words
A reading device for an optical data disk, characterized in that it comprises a detector matrix comprising a plurality of detectors arranged in parallel lines, the said detector matrix being coupled to a plurality of shift registers whereby electric charge generated by light falling on each detector is summed with the charge generated by light falling on previuos detectors and transferred at the disk rotating speed to the following detector, and in that the shift register receives the charge from the last detector in the column.
Claim 9
Dependent Claim
21 words
A reading device according to claim 8, characterized in that it further comprises a multiplexor unit to electronically access neighbouring tracks.
Claim 10
Dependent Claim
41 words
A device according to claim 4 or 5, characterized in that it further comprises image processing means to receive the data generated by the detector matrix and to translate said data into data contained in data spots located on the disk.
Claim 11
Independent Claim
44 words
A method of fast accessing data on an optical disk, characterized in that the data points are read from the optical disk by actuating a step and focus unit comprising in combination at least two mirrors which are displaceable along a common optical path.
Claim 12
Dependent Claim
28 words
A method according to claim 11, characterized in that each mirror is independently displaceable, whereby the unit can be used both for scanning data and for focusing purposes.
Claim 13
Independent Claim
110 words
A method of reading data from optical disks, which comprises providing a multi-disk system for the optical disk reader, characterized in that it comprises: a) an optical head comprising optical means to receive an image from an optical disk; b) a relay optics unit comprising a plurality of mirrors; and c) a plurality of disks, each of which is coupled to a mirror each being independently removable from the optical path; and in that the positioned relationship between the said mirrors and the said disk drivers is such that the optical path between each of the disks and the optical head is the same for all disks in the system.
Claim 14
Dependent Claim
24 words
A step and focus unit, characterized in that it comprises in combination at least two mirrors which are displaceable along a common optical path.
Claim 15
Dependent Claim
28 words
A unit according to claim 14, characterized in that each mirror is independently displaceable, whereby the unit can be used both for scanning data and for focusing purposes.
Claim 16
Dependent Claim
97 words
A multi disk system for an optical disk reader, characterized in that it comprises: a) an optical head comprising optical means to receive an image from an optical disk; b) a relay optics unit comprising a plurality of mirrors; and c) a plurality of disks, each of which is coupled to a mirror each being independently removable from the optical path; the positioned relationship between the said mirrors and the said disk drivers being such that the optical path between each of the disks and the optical head is the same for all disks in the system.
Claim 17
Dependent Claim
24 words
An optical disk reader, comprising: a) a light split head, as defined in the specification; and b) means for carrying out electronic track correction.
Claim 18
Independent Claim
67 words
A device for generating non-coherent light to be projected on an optical disk, characterized in that it comprises: a) one or more laser diodes; b) a fibre optics positioned with one end in front of the said laser diodes and at the other end in front of optical elements; and c) optical element to project the light received from the said fibre optics onto the optical disk.
Claim 19
Independent Claim
42 words
A method for acquiring track data from the multi-track image of an optical disk, characterized in that it comprises the steps of: 1) locating the track position within the said image; and 2) determining the length of data segments within each track.
Claim 20
Dependent Claim
23 words
A method according to claim 19, characterized in that it further comprises the step of subtracting each pixel from its cross track neighbour.
Claim 21
Dependent Claim
40 words
A method according to claim 19, characterized in that it further comprises the steps of: a) subtracting each pixel from its along track neighbour to generate its first difference; and b) subtracting the first differences in the cross track direction.
Claim 22
Dependent Claim
21 words
A method according to claim 20 or 21, characterized in that the subtraction operations are carried out by analog processing means.
Claim 23
Dependent Claim
21 words
A method according to claim 20 or 21, characterized in that the image obtained is processed in sub-pixel accuracy by interpolation.
Claim 24
Dependent Claim
30 words
A method according to claim 19, characterized in that the detection of the data segments is carried out by convolving the image of the data with an edge detection operator.
Claim 25
Dependent Claim
20 words
A method according to claim 24, characterized in that the said edge detection operator is the difference of two Gaussians.
Claim 26
Dependent Claim
31 words
A method according to claim 24, characterized in that the convolution operator is of varying kernel length utilizing short kernel at high dense areas and longer kernels at less dense areas.
Claim 27
Dependent Claim
19 words
A method according to claim 24, characterized in that a pre processor (PPD) filter is applied to the data.
Claim 28
Dependent Claim
20 words
A method according to claim 24, characterized in that the convolved track image is processed in sub-pixel accuracy by interpolation.
Claim 29
Dependent Claim
17 words
A method according to claim 24, characterized in that the convolutions are carried on by analog processing.
References Cited (Backward Citations)
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