US4331877A
Expired / Lapsed
US
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Transverse tomography with optical filtering
Assignee: University Patents Inc
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Filing: 1980-03-21
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Granted: 1982-05-25
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Expires: 2000-03-21
Abstract
Abstract The disclosure is directed to an apparatus and method for generating a two-dimensional back-projected image of a slice of an object, and also to an optical filtering apparatus and method which, inter alia, is useful therein. Successive beams of light are generated, each having a narrow elongated cross-section with an optical intensity that is a function of the density characteristic of the slice of the object as measured at a particular relative rotational angle. The beams are optically filtered and spread in a direction transverse to their length. Optical filtering with a filter function having both positive and negative components is preferably performed using a single-channel time modulated technique. A television camera receives the spread filtered beams. Relative rotation is effected between the beams and the camera, the rotation being related to the relative rotational angles of the object associated with the generation of the successive beams of light. A digital frame store accumulates the intensities sensed at elemental areas of the image sensing means. The accumulated intensities comprise a two-dimensional back-projected image of the slice of the object which can then be displayed on a television display. In a further form of the disclosure, back-projected images are obtained using an optical "loop" processor which employs a single-channel time modulated filtering technique.
Inventors
- 👤 Harrison H. Barrett
- 👤 William Swindell
- 👤 Scott Gordon
- 👤 John E. Greivenkamp, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:23
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/02; A61B6/025; H; H04; H04N; H04N23/00; H04N23/30; Y; Y10; Y10S; Y10S378/00; Y10S378/901
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
110 words
Apparatus for optically filtering a light beam with a filter function having a spatial characteristic that has both positive and negative components, and for producing an electronic representation of said filtered light beam, comprising: first optical filtering means representative of the positive component of said filter function; second optical filtering means representative of the negative component of said filter function; means for alternatively interposing said first and second filtering means in the path of said beam; electro-optical sensing means for receiving the filtered beam; means for combining successive electronic outputs of said electro-optical sensing means; and means synchronized with said interposing means for controlling the polarity of said combining means.
Claim 2
Dependent Claim
110 words
Apparatus for optically filtering a light beam with a filter function having a spatial characteristic that has both positive and negative components, and for producing an electronic representation of said filtered light beam, comprising: first optical filtering means representative of the positive component of said filter function; second optical filtering means representative of the negative component of said filter function; means for alternatively interposing said first and second filtering means in the path of said beam; electro-optical sensing means for receiving the filtered beam; means for combining successive electronic outputs of said electro-optical sensing means; and means synchronized with said interposing means for controlling the polarity of said combining means.
Claim 3
Dependent Claim
33 words
Apparatus as defined by claim 1 wherein said first and second optical filtering means are electro-optically switchable, and wherein said interposing means comprises means for controlling the electro-optical switching of said filtering means.
Claim 4
Dependent Claim
34 words
Apparatus as defined by claim 1 wherein said means for alternately interposing said optical filtering means includes means for mechanically interposing said first and second optical filtering means in the path of said beam.
Claim 5
Dependent Claim
21 words
Apparatus as defined by claim 3 wherein said first and second optical filtering means comprise different orientations of a Ronchi ruling.
Claim 6
Dependent Claim
138 words
Apparatus for generating a two-dimensional back-projected image of a slice of an object, comprising: means for generating successive beams of light, each having a narrow elongated cross-section with an optical intensity that is a function of the density characteristic of said slice of the object as measured at a particular relative rotational angle; means for spreading said beams in a direction transverse to their length; means for optically filtering said beams; two-dimensional electronic image sensing means for receiving the spread filtered beams; means for effecting rotation between said beams and said image sensing means, said rotation being related to said relative rotational angles of the object associated with the generation of said successive beams of light; and a digital frame store for accumulating electrical signals representative of the intensities sensed at elemental areas of said image sensing means.
Claim 7
Dependent Claim
138 words
Apparatus for generating a two-dimensional back-projected image of a slice of an object, comprising: means for generating successive beams of light, each having a narrow elongated cross-section with an optical intensity that is a function of the density characteristic of said slice of the object as measured at a particular relative rotational angle; means for spreading said beams in a direction transverse to their length; means for optically filtering said beams; two-dimensional electronic image sensing means for receiving the spread filtered beams; means for effecting rotation between said beams and said image sensing means, said rotation being related to said relative rotational angles of the object associated with the generation of said successive beams of light; and a digital frame store for accumulating electrical signals representative of the intensities sensed at elemental areas of said image sensing means.
Claim 8
Dependent Claim
15 words
Apparatus as defined in claim 5 further comprising means for displaying said accumulated image intensities.
Claim 9
Dependent Claim
56 words
Apparatus as defined by claim 5 wherein said optical filtering means comprises: a first optical filter representative of a first component of a filter function; a second optical filter representative of a second component of a filter function; and means for alternatively interposing said first and second optical filters in the path of said generated beams.
Claim 10
Dependent Claim
201 words
Apparatus for generating a two-dimensional back-projected filtered image of a slice of an object, comprising: photodetector means; illuminating means directed toward said photodetector means; carrier means disposed between said illuminating means and said photodetector means, said carrier means having a plurality of substantially parallel elongated projections on the surface thereof, each projection having an optical characteristic representing the density characteristic of said slice of the object as measured at a particular relative rotational angle; mask means also disposed between said illuminating means and said photodetector means, said mask means comprising a plurality of cycles of a substantially sinusoidally shaped pattern of varying amplitude; means for moving said carrier means and said mask means with respect to each other; a first optical filtering means representative of the positive component of a filter function; a second optical filtering means representative of the negative component of a filter function; means for alternately interposing said first and second optical filtering means in the path between said carrier means and said photodetector means; means synchronized with said interposing means for combining successive outputs of said photodetector means with opposite polarities; and display means responsive to the output of said combining means for displaying the back-projected image.
Claim 11
Dependent Claim
201 words
Apparatus for generating a two-dimensional back-projected filtered image of a slice of an object, comprising: photodetector means; illuminating means directed toward said photodetector means; carrier means disposed between said illuminating means and said photodetector means, said carrier means having a plurality of substantially parallel elongated projections on the surface thereof, each projection having an optical characteristic representing the density characteristic of said slice of the object as measured at a particular relative rotational angle; mask means also disposed between said illuminating means and said photodetector means, said mask means comprising a plurality of cycles of a substantially sinusoidally shaped pattern of varying amplitude; means for moving said carrier means and said mask means with respect to each other; a first optical filtering means representative of the positive component of a filter function; a second optical filtering means representative of the negative component of a filter function; means for alternately interposing said first and second optical filtering means in the path between said carrier means and said photodetector means; means synchronized with said interposing means for combining successive outputs of said photodetector means with opposite polarities; and display means responsive to the output of said combining means for displaying the back-projected image.
Claim 12
Dependent Claim
16 words
Apparatus as defined by claim 8 wherein said substantially sinusoidally shaped pattern is a sinusoidal transparency.
Claim 13
Dependent Claim
15 words
Apparatus as defined by claim 9 wherein said mask means comprises a movable endless loop.
Claim 14
Dependent Claim
15 words
Apparatus as defined by claim 10 wherein said display is synchronized with said moving means.
Claim 15
Dependent Claim
32 words
Apparatus as defined by claim 8 wherein said first and second optical filtering means are electro-optically switchable, and wherein said interposing means comprises means for controlling the electro-optical switching of said filters.
Claim 16
Dependent Claim
16 words
Apparatus as defined by claim 12 wherein said substantially sinusoidally shaped pattern is a sinusoidal transparency.
Claim 17
Dependent Claim
15 words
Apparatus as defined by claim 13 wherein said mask means comprises a movable endless loop.
Claim 18
Dependent Claim
15 words
Apparatus as defined by claim 14 wherein said display is synchronized with said moving means.
Claim 19
Dependent Claim
172 words
Apparatus for generating a two-dimensional back-projected image of a slice of an object, comprising: means for generating successive beams of light, each having a narrow elongated cross-section with an optical intensity that is a function of the density characteristic of said slice of the object as measured at a particular relative rotational angle; means for spreading said beams in a direction transverse to their length; a first optical filter representative of a first component of a filter function; a second optical filter representative of a second component of a filter function; means for alternatively interposing said first and second optical filters in the path of said generated beams; two-dimensional electronic image sensing means for receiving the spread filtered beams; means for effecting rotation between said beams and said image sensing means, said rotation being related to said relative rotational angles of the object associated with the generation of said successive beams of light; and means for accumulating electrical signals representative of the intensities sensed at elemental areas of said image sensing means.
Claim 20
Dependent Claim
172 words
Apparatus for generating a two-dimensional back-projected image of a slice of an object, comprising: means for generating successive beams of light, each having a narrow elongated cross-section with an optical intensity that is a function of the density characteristic of said slice of the object as measured at a particular relative rotational angle; means for spreading said beams in a direction transverse to their length; a first optical filter representative of a first component of a filter function; a second optical filter representative of a second component of a filter function; means for alternatively interposing said first and second optical filters in the path of said generated beams; two-dimensional electronic image sensing means for receiving the spread filtered beams; means for effecting rotation between said beams and said image sensing means, said rotation being related to said relative rotational angles of the object associated with the generation of said successive beams of light; and means for accumulating electrical signals representative of the intensities sensed at elemental areas of said image sensing means.
Claim 21
Dependent Claim
15 words
Apparatus as defined by claim 16 further comprising means for displaying said accumulated image intensities.
Claim 22
Dependent Claim
15 words
Apparatus as defined by claim 17 wherein said accumulating means comprises a digital frame store.
Claim 23
Dependent Claim
28 words
Apparatus as defined by claim 18 further comprising means for controlling said digital frame store to accumulate a plurality of frames for each of said beams of light.
Claim 24
Dependent Claim
24 words
Apparatus as defined by claim 19 wherein said means for effecting rotation between said beam and said image sensing means comprises image rotator optics.
Claim 25
Dependent Claim
51 words
Apparatus as defined by claim 20 wherein said means for generating said successive beams of light comprises means for illuminating individual one-dimensional optical projections, each having an optical characteristic that is a function of the density characteristic of said slice of the object as measured at a particular relative rotational angle.
Claim 26
Dependent Claim
39 words
Apparatus as defined by claim 16 wherein said first and second components of said filter function are respectively positive and negative components, and further comprising means synchronized with said interposing means for controlling the polarity of said accumulating means.
Claim 27
Dependent Claim
15 words
Apparatus as defined by claim 22 wherein said accumulating means comprises a digital frame store.
Claim 28
Dependent Claim
28 words
Apparatus as defined by claim 23 further comprising means for controlling said digital frame store to accumulate a plurality of frames for each of said beams of light.
Claim 29
Dependent Claim
24 words
Apparatus as defined by claim 24 wherein said means for effecting rotation between said beam and said image sensing means comprises image rotator optics.
Claim 30
Dependent Claim
51 words
Apparatus as defined by claim 25 wherein said means for generating said successive beams of light comprises means for illuminating individual one-dimensional optical projections, each having an optical characteristic that is a function of the density characteristic of said slice of the object as measured at a particular relative rotational angle.
Claim 31
Dependent Claim
31 words
Apparatus as defined by claim 23 wherein said first and second optical filters are electro-optically switchable, and wherein said interposing means comprises means for controlling the electro-optical switching of said filters.
Claim 32
Dependent Claim
15 words
Apparatus as defined by claim 27 wherein said accumulating means comprises a digital frame store.
Claim 33
Dependent Claim
28 words
Apparatus as defined by claim 28 further comprising means for controlling said digital frame store to accumulate a plurality of frames for each of said beams of light.
Claim 34
Dependent Claim
24 words
Apparatus as defined by claim 29 wherein said means for effecting rotation between said beam and said image sensing means comprises image rotator optics.
Claim 35
Dependent Claim
51 words
Apparatus as defined by claim 30 wherein said means for generating said successive beams of light comprises means for illuminating individual one-dimensional optical projections, each having an optical characteristic that is a function of the density characteristic of said slice of the object as measured at a particular relative rotational angle.
Claim 36
Dependent Claim
33 words
Apparatus as defined by claim 22 wherein said means for filtering interposing said optical filters includes means for mechanically interposing said first and second optical filters in the path of said generated beams.
Claim 37
Dependent Claim
20 words
Apparatus as defined by claim 32 wherein said first and second optical filters comprise different orientations of a Ronchi ruling.
Claim 38
Dependent Claim
15 words
Apparatus as defined by claim 33 wherein said accumulating means comprises a digital frame store.
Claim 39
Dependent Claim
28 words
Apparatus as defined by claim 34 further comprising means for controlling said digital frame store to accumulate a plurality of frames for each of said beams of light.
Claim 40
Dependent Claim
24 words
Apparatus as defined by claim 35 wherein said means for effecting rotation between said beam and said image sensing means comprises image rotator optics.
Claim 41
Dependent Claim
51 words
Apparatus as defined by claim 36 wherein said means for generating said successive beams of light comprises means for illuminating individual one-dimensional optical projections, each having an optical characteristic that is a function of the density characteristic of said slice of the object as measured at a particular relative rotational angle.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-05-24 | 1985-11-23 | 1986-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-24 | 1989-11-23 | 1990-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-24 | 1993-11-23 | 1994-05-25 | $7700.00 | Window Closed / Lapsed |