Optical translator device

• US 4,794,384 A
• Filed: 04/09/1987
• Issued: 12/27/1988
• Est. Priority Date: 09/27/1984
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Jackson, Stephen B.
• Primary Examiner(s): Caldwell, Sr., John W.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/037,094
• Time in Patent Office: 628 Days
• Field of Search: 340/710, 340/706, 340/709, 178/18, 356/28, 382/18, 382/28, 235/460, 250/221
• US Class Current: 345/166
• CPC Class Codes: G06F 3/0317 in co-operation with a patterned surface, e.g. absolute position or relative movement detection for an optical mouse or pen positioned with respect to a coded surface

Abstract

An optical translator device capable of providing information indicative of the amount and direction of relative movement between the device and a surface positioned relative thereto. The device comprises a light source for providing at least partially coherent radiation and the source radiation is directed toward an area of the surface area. The reflected coherent radiation or light at the surface area undergoes optical interference due to the texture of the surface thereby forming a speckle pattern consisting of light and dark features. A detector array at the device comprises a plurality of photodetector cells and positioned in the path to receive the reflected light and to detect the light and dark features as represented by the cells in the array detecting light features in the reflected light thereby representative of a sample of the speckle pattern. Means is provided to compare consecutively produced samples which are indicative of the translatory information. A particular application of the optical translator device is a novel optical cursor control device which derives its translatory information from movement on substantially any sufficiently reflective surface. The output of the detector array is provided to circuit means to produce signals indicative of the amount and direction of relative cursor control device movement over the surface based upon observation of changes and movement of the speckle pattern as presented to the detector array. Such a device can be characterized as a "padless optical mouse" to provide orthogonal signals to move a cursor from position to position on a display screen in response to movement of the mouse over any sufficiently reflective surface, such as a desk top.

Claims

1. In an optical translator device that does not require a specific repetitive reflective pattern for operation and capable of providing information indicative of the amount and direction of relative movement between said device and an unpatterned surface having natural surface irregularities positioned relative thereto and comprising a light source having a sufficient degree of coherent radiation to provide a speckle pattern relative to said surface, said source directed toward an area of said surface wherein a portion of the light is reflected from said surface area, said reflected coherent light undergoing optical interference at said surface area due to the irregularity of said surface thereby forming a reflected speckle pattern consisting of light and dark features, a planar array at said device comprising a plurality of photodetector cells and positioned in a path to receive said reflected pattern and to permit said cells to detect said light features, the values of said cells responsive to said light features representative of a sample of said speckle pattern, means to determine the degree of correspondence of the values of adjacently positioned cells in consecutively produced samples, said degree of correspondence indicative of said information, said means to determine comprises means to total the number of identical values achieved between a number of said array cells under consideration in a present sample as compared with neighboring adjacent cells of a previous sample aligned in orthogonal directions and in diagonal directions relative to said cells in said present sample, the highest value of such comparisons representative of the highest value of matches found to occur between adjacently positioned cells in one of said directions indicative of a preponderence as to the direction of speckle pattern movement and indicative of said information.

2. The optical translator device of claim 1 which includes circuit means to determine the number of said photodetector cells in a sample that have detected light features and means to compare said number with a predetermined value indicative of whether a sample is a valid representation of said sample speckle pattern.

3. The optical translator device of claim 2 wherein said means to determine comprises means to total the number of identical values achieved between a number of said array cells in a present sample as compared with neighboring adjacent cells of a previous sample aligned in orthogonal directions and in diagonal directions relative to said cells in said present sample, the highest value of such comparisons representative of the highest value of matches found to occur between adjacently positioned cells in one of said directions indicative of a preponderence as to the direction of speckle pattern movement and indicative of said information.

4. In a cursor control device that does not require a specific repetitive reflective pattern for operation and capable of providing information indicative of the amount and direction of relative movement of said device over a surface such as a desk top or the like having natural surface irregularities and comprising a light source having a sufficient degree of coherent radiation to provide a speckle pattern relative to said surface, said source directed toward an area of said surface wherein a portion of the light is reflected from said surface area, said reflected coherent light undergoing optical interference at said surface area due to the irregularity of said surface thereby forming a reflected speckle pattern consisting of light and dark features, a planar array comprising a plurality of photodetector cells and positioned in a path to receive said reflected pattern and to permit said cells to detect said light features, the values of said cells responsive to said light features representative of a sample of said speckle pattern, means to determine the degree of correspondence in the values of adjacently positioned cells in consecutively produced samples, the accumulated values of adjacently positioned cells that are identical being indicative of said information, said means to determine comprises means to total the number of identical values achieved between a number of said array cells under consideration in a present sample as compared with neighboring adjacent cells of a previous sample aligned in orthogonal directions and in diagonal directions relative to said cells in said present sample, the highest value of such comparisons representative of the highest value of matches found to occur between adjacently positioned cells in one of said directions indicative of a preponderence as to the direction of speckle pattern movement and indicative of said information.

5. The cursor control device of claim 4 which includes circuit means to determine the number of said photodetector cells in a sample that have detected light features and means to compare said number with a predetermined value indicative of whether a sample is a valid representation of said sample speckle pattern.

6. The optical translator device of claim 5 wherein said means to determine comprises means to total the number of identical values achieved between a number of said array cells under consideration in a present sample as compared with neighboring adjacent cells of a previous sample aligned in orthogonal directions and in diagonal directions relative to said cells in said present sample, the highest value of such comparisons representative of the highest value of matches found to occur between adjacently positioned cells in one of said directions indicative of a preponderence as to the direction of speckle pattern movement and indicative of said information.

7. In a cursor control device that does not require a specific repetitive reflective pattern for operation to provide an output indicative of the amount and direction of relative movement of the device over an unpatterned surface having natural surface irregularities, said output utilized for moving a cursor from position to position on a display screen, said cursor device comprising a housing, a light source supported in said housing having a sufficient degree of coherent radiation to provide a speckle pattern relative to said surface and directed toward said surface over which said housing is moved, a detector array comprising a plurality of photodetector cells supported in said housing and positioned to receive light reflected from said surface, said reflected coherent light undergoing optical interference due to the irregularity of said surface thereby forming a reflected speckle pattern consisting of light and dark features, the contrast between said light and dark features being detected by photodetector cells represented by a value from each of said cells above or below a predetermined threshold, and circuit means coupled to said array to process said values from said array of photodetector cells to determine if a sufficient number of said cells have sensed a predetermined amount of light representative of a valid sample and means to determine the degree of correspondence relative to sample cell values obtained from a present sample with adjacent sample cell values obtained from a previous sample, the accumulated corresponding values of said adjacent values that are identical being indicative of the direction of movement of said cursor control device relative to said surface and correspondingly the direction of movement for said cursor on said display screen, said means to determine comprises means to total the number of identical sample values achieved between a number of said array cells under consideration in said present sample as compared with neighboring adjacent cells of said previous sample aligned in orthogonal directions and in diagonal directions relative to said cells in said present sample, the highest value of such comparisons representative of the highest value of matches found to occur between adjacently positioned cells in one of said directions indicative of a preponderence as to the direction of speckle pattern movement and indicative of said information.

8. The cursor control device of claim 7 which includes circuit means to determine the number of said photodetector cells in said present sample that have detected light features and means to compare said number with a predetermined value indicative of whether said present sample is a valid representation of the sample speckle pattern.

9. The cursor control device of claim 8 wherein said means to determine comprises means to total the number of identical sample values achieved between a number of said array cells under consideration in said present sample as compared with neighboring adjacent cells of said previous sample aligned in orthogonal directions and in diagonal directions relative to said cells in said present sample, the highest value of such comparisons representative of the highest value of matches found to occur between adjacently positioned cells in one of said directions indicative of a preponderence as to the direction of speckle pattern movement and indicative of said information.

10. In an optical translator device capable of providing information indicative of the amount and direction of relative movement of said device over a textured surface not requiring a predetermined, repetitive pattern on said surface, such as a desk or the like, comprising

a planar two dimensional array positioned in said device having a plurality of photodetector cells and positioned in a path to receive a reflected image from said surface comprising a speckle pattern,

said cells being respectively responsive to randomly disposed light and dark features present in said reflected image speckle pattern,

means to sample the response from said cells to said image and store a value from each cell representative of a response level either above or below a given threshold to form a sample of said image,

means to compare a given cell value from a present sample formed from said array with circumferentially neighboring adjacent cells fo said given cell from a previous sample wherein said previous sample circumferentially neighboring adjacent cells are positionally aligned in both orthogonal directions and diagonal directions relative to said given cell in said present sample, said means to compare a present cell sample to a previous cell sample is continued for a plruality of said given cell values in said present sample and their corresponding circumferentially neighboring adjacent cells in said previous sample,

means to total the number of identical values determined between a number of said given cell values from said present sample and respective circumferentially neighboring cell values from said previous sample, the highest total number of said given cell values relative to respective circumferentially neighboring cell values with respect to a particular of said directions indicative of the direction of movement of said device relative to said image.

11. In the optical translator device of claim 10, wherein said surface is illuminated with coherent light and said image comprising a speckle pattern.

12. In the optical translator device of claim 11, wherein said coherent light is a laser beam.

13. In an optical translator device capable of providing information indicative of the amount and direction of relative movement between said device and a surface, said surface not requiring a predetermined, repetitive pattern thereon, but having natural surface irregularities such as a desktop or the like, means to illuminate said surface with radiation and reflect therefrom, said reflected radiation characterized by having a sufficient degree of coherent radiation to cause constructive and destructive interference in said reflected radiation due to said surface irregularities so as to form a reflected speckle pattern consisting of randomly disposed, sharply contrasting light and dark features, a planar array positioned on said device comprising several rows and columns of light detecting cells and aligned in a path to receive at least a portion of said reflected speckle pattern, said array cells being responsive to the light features in said reflected speckle pattern portion, said responsive cells representative of a sample of said reflected speckle pattern portion and means to correlate between consecutively produced speckle pattern samples to determine said information, said means to correlate including means to identify identical matches between individual cells of a first of such samples with adjacent neighboring cells of those individual cells in a second of such samples.

14. In the optical translator device of claim 13 wherein said speckle pattern features are larger than the size of an array cell and the minimum speckle size, a, is determined by

15. In the optical translator device of claim 14 wherein said illumination means is a laser beam.