Method and apparatus for processing of reconstructed holographic images of digital data patterns

• US 5,694,488 A
• Filed: 02/21/1996
• Issued: 12/02/1997
• Est. Priority Date: 12/23/1993
• Status: Expired due to Term

• Current Assignee: ForceTEC Co., Ltd. (Duk-Soo Kang)
• Original Assignee: Tamarack Storage Devices
• Inventors: Hartmann, Alfred Clyde
• Primary Examiner(s): Couso, Jose L.
• Application Number:
  US08/604,263
• Time in Patent Office: 650 Days
• Field of Search: 382/210, 382/302, 359/1, 359/16, 359/29, 359/32, 359/35, 250/208.1, 250/208.2
• US Class Current: 382/210
• CPC Class Codes: G06T 5/20 using local operators

Abstract

A method and apparatus for reconstructing holographic images is disclosed. A holographic image is recreated from a holographic storage media (10) by passing a reference beam (38) therethrough, which holographic image comprises a composite data image of discrete binary images arranged in an array. A reconstructed data beam (58) is then directed onto a detector array (42), resulting in a reconstructed composite data image (62) formed on the surface thereof. The detector (42) is comprised of a plurality of detector elements or pixels (92) arranged in an array corresponding to the original array of binary data images that are associated with the reconstructed composite data image (62). The reconstructed composite data image is oversampled such that each discrete binary image in the reconstructed composite data image is associated with, for example, four of the detector elements (92) which define pixels. Each group of pixels that is associated with an image is defined as a bixel. A 2×2 Margolus neighborhood or other suitable cell neighborhood is defined that is scanned across the array in a predetermined manner and transformation rules applied to the output of the four pixels within the Margolus neighborhood window (90). In a first pass, contrast enhancement is provided wherein if one of the pixels is a gray pixel, it is forced to the state of the other pixels. The edges are then defined and then the overall pixels aligned. A new image is created and then processed in accordance with standard techniques to extract the data therefrom.

Claims

1. A method for receiving an optically generated two dimensional composite data image comprised of a plurality of discrete multi-state data images and correcting for any distortions in the composite data image, comprising the steps of:

providing a detector array having a plurality of pixel detector elements aligned in a pattern substantially corresponding to the position of the discrete multi-state data images in the composite data image under ideal circumstances, each of said pixel elements having an output that varies from a low intensity level to a high intensity level, with the multi-state levels corresponding to finite predetermined intensity levels;

disposing the composite data image on the detector array;

processing the output of the detector array when the composite data image is misaligned with respect to the pixels in the detector array, which misalignment may cause the output of the pixels to be ambiguous in certain areas of the detector array with a level between the finite predetermined intensity levels associated with the multi-state levels, the step of processing utilizing a cellular automata algorithm to alter the output of select ones of the pixels to an intensity level associated with one of the multiple state levels determined by the cellular automata algorithm to be correct state in order to create a reconstructed composite image; and

outputting the reconstructed composite image for decoding of the data therein.

2. The method of claim 1, and further comprising decoding the data from the reconstructed composite image.

3. The method of claim 1, wherein the multi-state data images are binary data images.

4. The method of claim 3, wherein the pattern on the detector array is a two-dimensional grid with each of the discrete data images being polygonal in shape and disposed adjacent each other.

5. The method of claim 4, wherein each discrete data image is associated with a plurality of the pixels in the detector array.

6. The method of claim 5, wherein the step of processing comprises:

creating at least one state machine cell for encompassing a predetermined number of pixels in the detector array; and

altering the state of the pixels in the state machine cell in accordance with predetermined transformation rules based upon the output of the pixels associated with the state machine cells.

7. The method of claim 6, wherein the step of creating at least one state machine cell comprises creating a plurality of state machine cells associated with different pixels that operate in parallel.

8. The method of claim 6, and further comprising moving the state machine cell in accordance with a processing algorithm such that the step of processing moves the cell across the two-dimensional surface of the array output.

9. The method of claim 8, wherein the step of moving the state machine cell across the two-dimensional surface of the array output comprises moving a plurality of cells across the two-dimensional surface of the array output in a pipeline manner.

10. The method of claim 6, wherein the transformation rules operate to adjust the contrast of the composite image by converting the output of pixels having an output between two of the multi-state levels to only one of the multi-state levels in accordance with predetermined threshold criteria.

11. The method of claim 6, and further comprising, designating which of the pixels within the cell are associated with a horizontal or vertical edge.

12. The method of claim 6, wherein the state machine cell encompasses only the number of cells associated with a single discrete data image and the transformation rules are operable to designate one of the pixels as a data image designator whenever it is determined by the transformation rules that the state machine cell is disposed over the pixels associated with one of the data images.