US5446271A — Omnidirectional scanning method and apparatus

Claim 1

Independent Claim 86 words

A method of reading encoded symbols comprising the steps of: generating a pattern of virtual scan lines traversing a two-dimensional imaging region, said pattern of virtual scan lines comprising less than the entirety of said two-dimensional imaging region, obtaining a stream of raster data over said two-dimensional imaging region, prior to storing any of said raster data, identifying a select portion of said raster data corresponding to said virtual scan lines, storing said select portion of raster data, and decoding said select portion of raster data.

Claim 2

Independent Claim 86 words

A method of reading encoded symbols comprising the steps of: generating a pattern of virtual scan lines traversing a two-dimensional imaging region, said pattern of virtual scan lines comprising less than the entirety of said two-dimensional imaging region, obtaining a stream of raster data over said two-dimensional imaging region, prior to storing any of said raster data, identifying a select portion of said raster data corresponding to said virtual scan lines, storing said select portion of raster data, and decoding said select portion of raster data.

Claim 3

Dependent Claim 15 words

A method as in claim 1 wherein the encoded symbol comprises a bar code label.

Claim 4

Dependent Claim 14 words

A method as in claim 1 wherein said raster data comprises light intensity data.

Claim 5

Dependent Claim 52 words

A method as in claim 1 further comprising the step of storing said select portion of raster data in an intermediate buffer prior to said step of storing said select portion of raster data in memory but after identifying said select portion of said raster data corresponding to said virtual scan lines.

Claim 6

Dependent Claim 23 words

A method as in claim 1 wherein said step of obtaining a stream of raster data is accomplished using a two-dimensional imaging array.

Claim 7

Dependent Claim 15 words

A method as in claim 5 wherein said two-dimensional imaging array comprises a CCD array.

Claim 8

Dependent Claim 41 words

A method as in claim 1 wherein the step of obtaining a stream of raster data further comprises the step of moving a single line scanner relative to said encoded symbol in order to obtain two dimensions of said raster data.

Claim 9

Dependent Claim 27 words

A method as in claim 7 wherein said step of moving a single line scanner relative to said encoded symbol is accomplished by use of a conveyor.

Claim 10

Dependent Claim 28 words

A method as in claim 7 wherein said single line scanner is selected from the group consisting of: a linear imaging array and a flying spot optical scanner.

Claim 11

Dependent Claim 26 words

A method as in claim 1 wherein said pattern of virtual scan lines is generated according to the dimensions of the encoded symbol to be read.

Claim 12

Dependent Claim 49 words

A method as in claim 1 wherein said step of storing said select portion of raster data further comprises the step of storing said select portion of raster data in an array of memory areas, wherein each of said memory areas is associated with a particular virtual scan line.

Claim 13

Dependent Claim 28 words

A method as in claim 1 wherein the step of decoding said select portion of raster data comprises interpolating said select portion of raster data to sub-pixel resolution.

Claim 14

Dependent Claim 48 words

A method as in claim 2 further comprising the step of counting the number of edges of said bar code label and not completing said step of decoding said select portion of raster data unless there are enough bars and spaces to form a minimum decodable label piece.

Claim 15

Dependent Claim 44 words

A method as in claim 2 wherein said step of generating a pattern of virtual scan lines further comprises the step of generating a plurality of families of parallel lines, each family separated by no more than a maximum angle from the next family.

Claim 16

Dependent Claim 55 words

A method as in claim 14 wherein said maximum angle is no larger than the angle defined by the equation 2 * Arctan (H/2W), wherein W is a maximum expected apparent width of a minimum decodable portion of said bar code label and H is a minimum expected apparent height of said bar code label.

Claim 17

Dependent Claim 40 words

A method as in claim 1 further comprising the step of optimizing the generation of said pattern of virtual scan lines by translating selected virtual scan lines slightly to eliminate or increase points in common with other virtual scan lines.

Claim 18

Dependent Claim 85 words

A method as in claim 1 further comprising the step of optimizing the generation of said pattern of virtual scan lines by replacing selected single virtual scan lines with two shorter virtual scan lines, the first of which originates from an end point of the original virtual scan line and terminates at a point slightly displaced from the original virtual scan line, and the second of which originates from the termination point of the first to the opposite endpoint of the original virtual scan line.

Claim 19

Dependent Claim 28 words

A method as in claim 1 wherein said step of obtaining a stream of raster data comprises scanning said raster data at a rate of approximately 10 Megahertz.

Claim 20

Dependent Claim 48 words

A method as in claim 14 further comprising the step of, for each virtual scan line family, dividing said imaging region into subregions having an identical virtual scan line pattern for the particular family, and selecting portions of raster data according to the pattern defined in the subregion.

Claim 21

Dependent Claim 22 words

A method as in claim 14 wherein each family of parallel lines is separated by the same angle from the next family.

Claim 22

Dependent Claim 15 words

A method as in claim 20 wherein said maximum angle divides integrally into 180 degrees.

Claim 23

Independent Claim 79 words

A system for reading encoded symbols comprising: an optical sensor, a generator for generating a pattern of virtual scan lines traversing a two-dimensional imaging region, a selector receiving serial raster data from said optical sensor and outputting a selected portion of said raster data, the selected portion comprising only raster data falling on said virtual scan lines, a memory capable of storing said selected portion of raster data, and a processor for decoding said selected portion of raster data.

Claim 24

Independent Claim 79 words

A system for reading encoded symbols comprising: an optical sensor, a generator for generating a pattern of virtual scan lines traversing a two-dimensional imaging region, a selector receiving serial raster data from said optical sensor and outputting a selected portion of said raster data, the selected portion comprising only raster data falling on said virtual scan lines, a memory capable of storing said selected portion of raster data, and a processor for decoding said selected portion of raster data.

Claim 25

Dependent Claim 15 words

A system as in claim 22 wherein the encoded symbol comprises a bar code label.

Claim 26

Dependent Claim 17 words

A system as in claim 22 wherein said selected portion of raster data comprises light intensity data.

Claim 27

Dependent Claim 18 words

A system as in claim 22 further comprising an intermediate buffer connected between said selector and said memory.

Claim 28

Dependent Claim 15 words

A system as in claim 22 wherein said optical sensor comprises a two-dimensional imaging array.

Claim 29

Dependent Claim 15 words

A system as in claim 26 wherein said two-dimensional imaging array comprises a CCD array.

Claim 30

Dependent Claim 39 words

A system as in claim 22 wherein said optical sensor comprises a linear imaging array with a second dimension of said two-dimensional imaging region being provided by relative movement of said encoded symbol with respect to said optical sensor.

Claim 31

Dependent Claim 15 words

A system as in claim 28 further comprising a conveyor for providing said relative movement.

Claim 32

Dependent Claim 42 words

A system as in claim 22 wherein said optical sensor comprises a flying spot optical scanner with a second dimension of said two-dimensional imaging region being provided by relative movement of said encoded symbol with respect to said flying spot optical scanner.

Claim 33

Dependent Claim 16 words

A system as in claim 30 wherein said flying spot optical scanner comprises a laser scanner.

Claim 34

Dependent Claim 25 words

A system as in claim 22 wherein said pattern of virtual scan lines is determined according to dimensions of the encoded signal to be read.

Claim 35

Dependent Claim 30 words

A system as in claim 22 wherein said memory is comprised of an array of memory areas, each of said memory areas being associated with a particular virtual scan line.

Claim 36

Dependent Claim 20 words

A system as in claim 22 wherein said processor decodes said selected portion of raster data using sub pixel interpolation.

Claim 37

Dependent Claim 18 words

A system as in claim 34 further comprising a filter having an impulse response of substantially (sin x)/x.

Claim 38

Dependent Claim 55 words

A system as in claim 23 wherein said bar code label comprises bars and spaces, and said processor counts the number of transitions between bars and spaces in a particular virtual scan line and stops decoding for said virtual scan line unless there are enough bars and spaces to form a minimum decodable label piece.

Claim 39

Dependent Claim 35 words

A system as in claim 22 wherein said pattern of virtual scan lines comprises a plurality of families of parallel lines, each family separated by no more than a maximum angle from the next family.

Claim 40

Dependent Claim 64 words

A system as in claim 37 wherein said encoded symbol is a bar code label, and said maximum angle is no larger than the angle defined by the equation 2 * Arctan (H/2W), wherein W is a maximum expected apparent width of a minimum decodable portion of said bar code label and H is a minimum expected apparent height of said bar code label.

Claim 41

Dependent Claim 19 words

A system as in claim 22 wherein said raster data is scanned at a rate of approximately 10 Megahertz.

Claim 42

Dependent Claim 56 words

A system as in claim 37 wherein the selection of said raster data for storage into memory is carried out by dividing said imaging region for each scan line family into identical rectangular tiles having the same pattern for a given scan line family, and raster data is selected according to said pattern in said tile.

Claim 43

Dependent Claim 18 words

A system as in claim 40 wherein said pattern in said tile traverses a diagonal of said tile.

Claim 44

Dependent Claim 50 words

A system as in claim 40 wherein said tiles are further divided into subtiles either having a virtual scan line pattern identical to other subtiles for the family or having no virtual scan line pattern for the family, and raster data is selected according to said pattern in said subtiles.

Claim 45

Dependent Claim 26 words

A system as in claim 22 wherein the data stored in said memory comprises a derivative of an intensity variation along a given virtual scan line.

Claim 46

Dependent Claim 28 words

A system as in claim 22 wherein at least part of said optical sensor and said virtual scan line generator are located on the same integrated circuit device.

Claim 47

Dependent Claim 18 words

A system as in claim 22 further comprising means for detecting edges of elements of said encoded symbol.

Claim 48

Dependent Claim 12 words

A system as in claim 22 further comprising a microprocessor or microcontroller.

Claim 49

Dependent Claim 14 words

A system as in claim 22 further comprising point-of-sale equipment housing said optical sensor.

Claim 50

Dependent Claim 20 words

A system as in claim 22 wherein said processor uses knowledge of the virtual scan line boundaries to expedite decoding.

Claim 51

Dependent Claim 11 words

A system as in claim 22 further comprising a handheld scanner.

Claim 52

Dependent Claim 12 words

A system as in claim 22 further comprising a presentation mode scanner.

Claim 53

Dependent Claim 12 words

A system as in claim 22 further comprising a sweep mode reader.

Claim 54

Dependent Claim 22 words

A system as in claim 37 wherein each family of parallel lines is separated by the same angle from the next family.

Claim 55

Dependent Claim 15 words

A system as in claim 52 wherein said maximum angle divides integrally into 180 degrees.

Claim 56

Dependent Claim 32 words

A system as in claim 22 wherein said selected portion of raster data falling on said virtual scan lines consists of all of the raster data falling on said virtual scan lines.

Claim 57

Independent Claim 78 words

A system for reading encoded symbols comprising: an optical sensor, a set of virtual scan lines mapped onto a two-dimensional imaging region, pixel selection logic coupled to said optical sensor for receiving sequential pixel data over said imaging region and identifying from said pixel data select pixels falling on at least one of said virtual scan lines, a memory for storing from said sequential pixel data only said select pixels, and a processor for processing said stored pixels.

Claim 58

Independent Claim 78 words

A system for reading encoded symbols comprising: an optical sensor, a set of virtual scan lines mapped onto a two-dimensional imaging region, pixel selection logic coupled to said optical sensor for receiving sequential pixel data over said imaging region and identifying from said pixel data select pixels falling on at least one of said virtual scan lines, a memory for storing from said sequential pixel data only said select pixels, and a processor for processing said stored pixels.

Claim 59

Dependent Claim 21 words

A system as in claim 55 wherein one or more of said virtual scan lines comprise a sequence of adjacent pixels.

Claim 60

Dependent Claim 29 words

A system as in claim 55 wherein said memory comprises a series of memory areas and each of said memory areas is associated with a particular virtual scan line.

Claim 61

Dependent Claim 22 words

A system as in claim 55 wherein said optical sensor and said pixel selection logic are combined in a single integrated circuit.

Claim 62

Dependent Claim 34 words

A system as in claim 55 wherein said pixel selection logic further comprises means for dividing said imaging region into subregions, each of which has an identical and simpler pattern of virtual scan lines.

Claim 63

Independent Claim 90 words

A method of scanning encoded symbols in two dimensions comprising the steps of: moving an encoded symbol across a field of view of a line scanner, selecting a pattern of virtual scan lines covering a two-dimensional imaging region defined by the width of a field of view of said line scanner and a distance covered by the motion of said encoded symbol, and scanning said encoded symbol periodically as it crosses said field of view while storing only scanning data corresponding to one or more of said virtual scan lines.

Claim 64

Independent Claim 90 words

A method of scanning encoded symbols in two dimensions comprising the steps of: moving an encoded symbol across a field of view of a line scanner, selecting a pattern of virtual scan lines covering a two-dimensional imaging region defined by the width of a field of view of said line scanner and a distance covered by the motion of said encoded symbol, and scanning said encoded symbol periodically as it crosses said field of view while storing only scanning data corresponding to one or more of said virtual scan lines.

Claim 65

Dependent Claim 25 words

A method as in claim 60 wherein said step of moving the encoded symbol comprises moving the encoded symbol with a high inertia conveyor system.

Claim 66

Dependent Claim 46 words

A method as in claim 60 wherein said step of moving the encoded symbol comprises moving the encoded symbol on at least two adjacent conveyor belts having a relatively narrow gap between them, and said line scanner is located so that it scans through said gap.

Claim 67

Dependent Claim 18 words

A method as in claim 60 further comprising the step of incorporating said line scanner into point-of-sale equipment.

Claim 68

Dependent Claim 27 words

A method as in claim 63 wherein said point-of-sale equipment is selected from the group consisting of: a cash register, a keyboard cabinet, and a check stand.

Claim 69

Dependent Claim 15 words

A method as in claim 60 further comprising the step of decoding said scanning data.

Claim 70

Dependent Claim 28 words

A method as in claim 60 further comprising the step of obtaining overlapping area scans by starting a new area scan before completion of the previous area scan.

Claim 71

Independent Claim 69 words

A method of reading an image comprising the steps of: generating a pattern of virtual scan lines traversing a multi-dimensional imaging region, scanning an area to obtain data over said imaging region while storing only data from selected points lying on said virtual scan lines, and interpreting at least a portion of said stored data to determine a dimensional characteristic of an image projected onto said multi-dimensional imaging region.

Claim 72

Independent Claim 69 words

A method of reading an image comprising the steps of: generating a pattern of virtual scan lines traversing a multi-dimensional imaging region, scanning an area to obtain data over said imaging region while storing only data from selected points lying on said virtual scan lines, and interpreting at least a portion of said stored data to determine a dimensional characteristic of an image projected onto said multi-dimensional imaging region.

Claim 73

Dependent Claim 24 words

A method as in claim 67 wherein said step of scanning an area to obtain data further comprises the step of obtaining raster data.

Claim 74

Dependent Claim 16 words

A method as in claim 67 wherein said multi-dimensional imaging region is a two-dimensional imaging region.

Claim 75

Dependent Claim 28 words

A method as in claim 67 wherein said step of interpreting at least a portion of said stored data further comprises the step of decoding said stored data.

Claim 76

Dependent Claim 53 words

A method as in claim 67 wherein, for a projected image of a predefined apparent minimum height and width, at least one of said virtual scan lines traverses an entire dimension of the projected image no matter at what angle of orientation the projected image lies with respect to said multi-dimensional imaging region.

Claim 77

Independent Claim 96 words

A method of reading images comprising: generating a pattern of virtual scan lines over a multi-dimensional imaging region by selecting a family of substantially parallel virtual scan lines separated by a predefined distance and repeatedly rotating said family by a predefined angle, detecting light incident on said imaging region and generating a stream of sequential pixel data thereby, identifying and storing from said data stream only pixel data corresponding to selected points lying on said virtual scan lines, and determining from said stored pixel data a dimensional characteristic of an image projected onto said imaging region.

Claim 78

Independent Claim 96 words

A method of reading images comprising: generating a pattern of virtual scan lines over a multi-dimensional imaging region by selecting a family of substantially parallel virtual scan lines separated by a predefined distance and repeatedly rotating said family by a predefined angle, detecting light incident on said imaging region and generating a stream of sequential pixel data thereby, identifying and storing from said data stream only pixel data corresponding to selected points lying on said virtual scan lines, and determining from said stored pixel data a dimensional characteristic of an image projected onto said imaging region.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1998-08-28	1999-02-27	1999-08-29	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2002-08-28	2003-02-27	2003-08-29	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2006-08-28	2007-02-27	2007-08-29	$7700.00	Window Closed / Lapsed

Omnidirectional scanning method and apparatus

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