Image quality compensation method and apparatus for holographic data storage system
First Claim
1. A method for reading data in a holographic storage system comprising:
- directing a light beam at an holographic storage medium for projecting an image on a detector, said storage medium containing an image of at least one page of data;
monitoring a quality of a projection of a page indicator image stored in said storage medium, said page indicator being stored in said medium such that the quality of its projected image is indicative of the projected quality of the corresponding data page image on said detector;
varying a parameter of said system originally used to store said data page and said page indicator in said storage medium; and
based on said monitored quality of the page indicator image projection, varying further said parameter or not varying said parameter and reading data from said data page projected on said detector.
7 Assignments
0 Petitions
Accused Products
Abstract
Feedback is employed in a holographic memory system to facilitate rapid access to information in a stored data page. This feedback technique provides compensation for thermal, optical and/or mechanical variations in the system components that tend to interrupt the projection of a data page image on a sensor array. A page indicator or mark is stored in a holographic storage medium with a page of data such that, during playback, a quality, e.g., intensity, of its projected image is indicative of the quality of the corresponding projected data page image. A corresponding page indicator sensor is employed with the associated sensor array to detect the quality of a projected page indicator image. The projected data page image can then be read by sensor elements of the detector based on the detected quality of the page indicator image. Such a detector can be implemented in an active pixel sensor (APS) array with the page indicator sensor being implemented as a region of the APS array. Registration of the sensor array elements with respect to projected data pixels of the data page image can also be aligned to an absolute or substantially nearest pixel alignment by a similar feedback technique.
-
Citations
22 Claims
-
1. A method for reading data in a holographic storage system comprising:
-
directing a light beam at an holographic storage medium for projecting an image on a detector, said storage medium containing an image of at least one page of data; monitoring a quality of a projection of a page indicator image stored in said storage medium, said page indicator being stored in said medium such that the quality of its projected image is indicative of the projected quality of the corresponding data page image on said detector; varying a parameter of said system originally used to store said data page and said page indicator in said storage medium; and based on said monitored quality of the page indicator image projection, varying further said parameter or not varying said parameter and reading data from said data page projected on said detector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A data storage system comprising:
-
a detector; a light source for directing a light beam at a holographic storage medium having at least one page of data and a corresponding page indicator image stored therein, said page indicator being stored in said medium such that its projected image quality is indicative of a projected image quality of said data page on said detector; a page indicator sensor associated with said detector, said light beam causing a projected image on said detector, wherein said page indicator sensor detects a quality of the projected image of said page indicator image; and a controller coupled to said page indicator sensor, said controller monitoring a quality of said page indicator image detected by said sensor and based on said monitored quality of the page indicator image projection, varying further said parameter or not varying said parameter and reading data from said data page projected on said detector. - View Dependent Claims (17, 18, 19, 20, 21, 22)
-
Specification