EP0171284A2
Expired / Lapsed
EP
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Optical digitizer
Assignee: NEC Corp
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Filing: 1985-08-07
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Granted: —
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Expires: 2005-08-07
Abstract
Abstract A cursor device (100) is movable manually over a transparent plate (10) beneath which can be disposed a document (20) bearing markings (22) to be traced by an index mark (114) in a projecting arm (112). A cursor device (100) is thereby positioned relative to fluoroscent markings (12) on the transparent plate (10). The fluorescent markings are illuminated by light of one wavelength from a source (122) and a filter (124) in a housing (110) of the cursor device. Fluorescent light thereby stimulated is collected by a lens (126) passed by a filter (128) and received by a charge coupled device sensor (130). When a switch (140) is operated to complete a circuit, the signals from the charge coupled device (130) are passed to a processor (200) which can determine the position and orientation of the cursor device (100) because of the distinctive pattern information in the fluorescent markings (12).
Inventors
- 👤 Yoichi Sato
- 👤 Kazuo Ichinokawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 08:32
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/0304; G06F3/0317; G06F3/0321
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
107 words
An optical digitizer, comprising a light active surface (10) located, in use, above a graphic data recording medium (20), the light active surface comprising light emitting regions (12) arranged so as to define a pattern; and means (100) having a light irradiating (122) and sensing (130) function movable on the light active surface, the pattern (12) on the light active surface (10) being responsive to irradiating light from the said means to emit light having a wavelength different from that of the irradiating light, thereby to determine position co-ordinates of graphic data on the recording medium on the basis of the light sensed by the said means.
Claim 2
Dependent Claim
107 words
An optical digitizer, comprising a light active surface (10) located, in use, above a graphic data recording medium (20), the light active surface comprising light emitting regions (12) arranged so as to define a pattern; and means (100) having a light irradiating (122) and sensing (130) function movable on the light active surface, the pattern (12) on the light active surface (10) being responsive to irradiating light from the said means to emit light having a wavelength different from that of the irradiating light, thereby to determine position co-ordinates of graphic data on the recording medium on the basis of the light sensed by the said means.
Claim 3
Dependent Claim
36 words
An optical digitizer as set forth in claim 1, characterised in that the pattern is configured as an array of fluorescent regions (12) emitting fluorescent light having a wavelength longer than that of the irradiating light.
Claim 4
Dependent Claim
173 words
An optical digitizer comprising a light active surface (10) located, in use, above a graphic data recording medium (20), the light active surface comprising light emitting regions (12) arranged so as to define a co-ordinate correlative pattern; and optical recognition means (100) movable on the light active surface, the optical recognition means comprising first means (112,114) which can be visually traced over data (22) on the recording medium (20) in accordance with movements of the optical recognition means, thereby to effect positioning of the optical recognition means with respect to the data (22); an optical system (122,124) adapted to irradiate the light active surface (10); and sensing means (128,130) adapted to sense light having a wavelength different from that of the irradiating light and emitted from a part of the co-ordinate correlative pattern falling within a field of view of the optical recognition means (100), thereby to produce a corresponding electric signal on the basis of which computation may be effected to determine position co-ordinates of the graphic data on the recording medium.
Claim 5
Dependent Claim
173 words
An optical digitizer comprising a light active surface (10) located, in use, above a graphic data recording medium (20), the light active surface comprising light emitting regions (12) arranged so as to define a co-ordinate correlative pattern; and optical recognition means (100) movable on the light active surface, the optical recognition means comprising first means (112,114) which can be visually traced over data (22) on the recording medium (20) in accordance with movements of the optical recognition means, thereby to effect positioning of the optical recognition means with respect to the data (22); an optical system (122,124) adapted to irradiate the light active surface (10); and sensing means (128,130) adapted to sense light having a wavelength different from that of the irradiating light and emitted from a part of the co-ordinate correlative pattern falling within a field of view of the optical recognition means (100), thereby to produce a corresponding electric signal on the basis of which computation may be effected to determine position co-ordinates of the graphic data on the recording medium.
Claim 6
Dependent Claim
29 words
An optical digitizer as set forth in claim 3, characterised in that graphic data recording medium (20) is a paper sheet on which figures or characters (22) are described.
Claim 7
Dependent Claim
41 words
An optical digitizer as set forth in claim 3 or 4, characterised in that the light active surface is composed of a transparent flat plate (10) on or in which the co-ordinate correlative pattern (12) is described with a fluorescent paint.
Claim 8
Dependent Claim
45 words
An optical digitizer as set forth in claim 5, characterised in that the fluorescent paint is Rhodamine B having an absorption peak at a wavelength of 550 to 560 nm and a luminance peak of the fluorescent light at a wavelength of about 590 nm.
Claim 9
Dependent Claim
48 words
An optical digitizer as set forth in claim 5 or 6, characterised in that the co-ordinate correlative pattern (12) is capable of emitting fluorescent light in response to the irradiating light from the optical system, the fluorescent light having a wavelength longer than that of the irradiating light.
Claim 10
Dependent Claim
54 words
An optical digitizer as set forth in claim 5, 6 or 7, characterised in that the optical recognition means (100) is configured as a manually positionable cursor device movable on the flat plate (10), the cursor device being provided with a hollow casing (110) having an opening over the surface of the flat plate.
Claim 11
Dependent Claim
42 words
An optical digitizer as set forth in claim 8, characterised in that the first means is composed of a positioning arm (112) having an index mark (114), projecting from the outer periphery of the hollow casing (110) of the cursor device (100).
Claim 12
Dependent Claim
53 words
An optical digitizer as set forth in any of claims 3 to 9, characterised in that the optical system cemprises a light source (122) emitting the irradiating light, and an optical filter (124) having an optical characteristic such as to cut off light having a wavelength longer than that of the irradiating light.
Claim 13
Dependent Claim
56 words
An optical digitizer as set forth in claim 10, characterised in that the optical system comprises a set of light sources (122A,B) radiating light fluxes having the same wavelength, and a set of optical filters (124A,B) having an optical characteristic such as to cut off light having a wavelength longer than that of the light sources.
Claim 14
Dependent Claim
25 words
An optical digitizer as set forth in claim 10 or 11, characterised in that the light source (122) is a light emitting diode of GaP.
Claim 15
Dependent Claim
29 words
An optical digitizer as set forth in claim 12, characterised in that the light emitting diode (122) emits light having a peak luminance at a wavelength of 555 nm.
Claim 16
Dependent Claim
38 words
An optical digitizer as set forth in any of claims 10 to 13, characterised in that the first optical filter (124) has an optical characteristic such as to cut off light having a wavelength longer than 570 nm.
Claim 17
Dependent Claim
25 words
An optical digitizer as set forth in any of claims 10 to 14, characterised in that the sensing means comprise a charge coupled sensor (130).
Claim 18
Dependent Claim
75 words
An optical digitizer as set forth in claim 15, insofar as dependent on claim 7, characterised in that the sensing means further comprises a convex lens (126) and a second optical filter (128) having an optical characteristic such as to cut off light having a wavelength shorter than that of the fluorescent light, the convex lens and second optical filter being provided in the path of the fluorescent light to the charge coupled sensor (130).
Claim 19
Dependent Claim
34 words
An optical digitizer as set forth in claim 16, characterised in that the second optical filter (128) has an optical characteristic such as to cut off light having a wavelength shorter than 570 nm.
Claim 20
Dependent Claim
39 words
An optical digitizer as set forth in any of claims 3 to 17, characterised in that the optical recognition means (100) further comprises a switch (140) connected to the sensing means (130) and to a graphic data processor (200).
Claim 21
Dependent Claim
38 words
An optical digitizer as set forth in any of claims 3 to 18, characterised in that the optical recognition means (100) further comprises a semiconductor memory (132) for temporarily storing image information sensed by the sensing means (128,130).
Claim 22
Dependent Claim
42 words
An optical digitizer as set forth in any of claims 3 to 19, characterised in that the co-ordinate correlative pattern (12) is provided in the form of lattice defined by a plurality of longitudinal and lateral straight lines intersecting with each other.
Claim 23
Dependent Claim
31 words
An optical digitizer as set forth in claim 20, characterised in that the spacings both between the longitudinal lines and between the lateral lines are integral multiples of a unit length.
Claim 24
Dependent Claim
74 words
An optical digitizer as set forth in claim 21, characterised in that binary digits (ones and zeros) are assigned to respective co- ordinate locations corresponding to the integral multiples of the unit length in the longitudinal and lateral directions of the lattice pattern, depending upon whether the longitudinal and lateral lines exist or not at the respective co-ordinate locations, thus to express the respective co-ordinate locations by code sequences defining a maximum period sequence.
Claim 25
Dependent Claim
23 words
An optical digitizer as set forth in claim 22, characterised in that the maximum period sequence is created by a circulating shift register.
Claim 26
Dependent Claim
56 words
An optical digitizer as set forth in claim 23, characterised in that the maximum period sequence created by N stages of a circulating shift register is defined by repetition of a bit pattern having a bit length of (2 N- 1), thus creating (2 N- 1) kinds of successive N bit codes different from each other.
Claim 27
Dependent Claim
40 words
An optical digitizer as set forth in claim 22, 23 or 24, characterised in that projected image data corresponding to a part of the lattice pattern which falls within the said field of view is sensed by the sensing means.
Claim 28
Dependent Claim
160 words
An optical digitizer as set forth in claim 25, in combination with a processor (200) adapted to execute processing for determining position co-ordinates and a rotational angle of the optical recognition means (100) on the light active surface (10), the processing being carried out by finding out data indicative of an arbitrary single straight line from the projected image data corresponding to the part pattern optically sensed by the sensing means (130) to calculate the rotational angle with respect to a longitudinal or lateral line within the said field of view using the data indicative of the arbitrary single straight line, calculating respective spacings between a plurality of longitudinal and lateral lines within the said field of view to determine a corresponding successive N bit code from the respective spacings thus calculated to find out a section to which the centre of the field of view belongs, thus to calculate position co-ordinates of the centre of the field of view.
Claim 29
Dependent Claim
68 words
An optical digitizer as set forth in claim 26, characterised in that the processor (200) is operative to execute a further processing for determining position co-ordinates of the graphic data recording medium by using a distance between the centre of the field of view and a predetermined position of the first means (112,114), the rotational angle, and the position co-ordinates of the centre of the field of view.
Claim 30
Dependent Claim
38 words
An optical digitizer as set forth in claim 27, characterised in that a sequence comprising the processing and the further processing is periodically executed only while the optical recognition means (100) and the processor (200) are electrically coupled.
References Cited (Backward Citations)
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