GB2254691A - Displacement monitoring system using two light beams - Google Patents
Displacement monitoring system using two light beams Download PDFInfo
- Publication number
- GB2254691A GB2254691A GB9207780A GB9207780A GB2254691A GB 2254691 A GB2254691 A GB 2254691A GB 9207780 A GB9207780 A GB 9207780A GB 9207780 A GB9207780 A GB 9207780A GB 2254691 A GB2254691 A GB 2254691A
- Authority
- GB
- United Kingdom
- Prior art keywords
- beams
- light
- displacements
- separation
- incident
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb
- A61B5/113—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb occurring during breathing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/026—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness by measuring distance between sensor and object
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/50—Systems of measurement based on relative movement of target
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Electromagnetism (AREA)
- Biophysics (AREA)
- General Health & Medical Sciences (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Medical Informatics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- Pathology (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Dentistry (AREA)
- Physiology (AREA)
- Computer Networks & Wireless Communication (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Detergent Compositions (AREA)
Abstract
A method of and apparatus for detecting movements of a surface (15) of a body (5) in which two beams of light (8, 9) arc directed at the body (5) at an angle to each other and changes in their separation (3x) where they impinge on the body arc monitored to detect changes in the position of the body (5) relative to a reference plane (3). The system may comprise of a single laser (1) arranged to supply two infra-red radiation beams (8, 9) which can be modulated to avoid interference. The system may be scanned in two dimensions within the plane normal to that of the two radiation beams and the signals processed for assessing relative displacements. <IMAGE>
Description
The Monitoring of Displacements
The present invention relates to the monitoring of displacements and more particularly to monitoring displacements due to changes in physical parameters such as the size, configuration or position of a solid body.
A number of circumstances can arise in which it is necessary to monitor displacements due to changes in the size, configuration or position of a solid body. For example, one may wish to monitor deflections of a beam or the wall of a pressure vessel under load, or the breathing or position of a sleeping or otherwise unconscious person.
Many methods exist for carrying out such an operation ranging from contact probes to interferometric methods. It is an object of the present invention to provide a method of, and apparatus for, monitoring displacements of a body, which are non-contacting and unobtrusive.
According to the invention there is provided a method of monitoring displacements of a surface of a body comprising the operations of establishing a reference plane with respect to a body displacements of a surface of which are to be monitored, directing two beams of light at the body at an angle to each other, determining the separation between the points at which the two beams are incident upon the body and detecting temporal changes in the separation of the two positions at which the beams of light are incident upon the body thereby to monitor displacements of the surface of the body.
Also according to the invention there is provided an apparatus for monitoring displacements of an element of a surface of a body, comprising means for producing two beams of light and projecting them at an angle to each other onto an element of a surface of a body displacements of which are to be monitored, means for measuring the separation between the positions on the body at which the two beams of light are incident to determine a measure of the distance between the element of the surface of the body and a reference plane associated with the body, means for detecting temporal changes in the separation between the positions at which the two beams of light are incident upon the element of the body to determine displacements of the element of the surface of the body and means for indicating the displacements of the surface of the body.
Preferably there is included means for repeatedly scanning the two beams of light over the surface of the body in a direction normal to the line joining the positions at which the two beams of light are incident upon the surface of the body, the scanning means being adapted to move in the said reference plane, means for storing data relating to the measurements made during one scan of the separation between the positions at which the two beams of light are incident upon the body, means for comparing the stored data with corresponding data acquired in a succeeding scan of the beams of light over the body and means for providing an indication of any differences between the compared data thereby to monitor displacements relating to the body.
Displacements relating to a body which can be monitored by the present invention include changes in the size, configuration or position of the body.
The invention will now be explained and described, by way of example, with reference to the accompanying drawing which is a diagrammatic representation of an apparatus for monitoring the movements of the body of a sleeping person.
Referring to the drawing, a laser source 1 of infra red radiation is mounted upon a carriage 2 which is adapted to be moved, by means not shown, in a plane 3 (x,y) a distance z above a bed 4 upon which is a person 5. The output beam 6 from the laser 1 is divided by a beam splitter 7 and formed into two beams 8 and 9. The beam 8 is directed directly at the person 5 and the beam 9 is directed also at the person 5 by means of a mirror 10. The beams of light 8 and 9 are arranged to converge at an angle 0, but to be separated by a distance Ex where they impinge upon the body of the person 5. A position sensing detector 11 is arranged to observe the position where the beams of light 8 and 9 are incident upon the person 5 and produce data signals related thereto.The data signal from the detector 11 are applied to a store 12, a comparator 13, and thence to a monitor 14. Also applied to the store 12 are signals related to the position of the carriage 1 in the reference plane 3.
The separation Ex between the points where the beams 8 and 9 impinge on the body of the person 5 is a function of the angle 8 and the distance z between the upper surface 15 of the body of the person 5 and the reference plane 3.
Assuming the scan of the carriage is regular, the co-ordinates (x,y) of any given point 0 in a complete scan of the carriage 2 in the (xy) plane 3 between limits x = 0 ~ X and y = 0 B Y can be deduced from measurements of the time which has elapsed from the beginning of a scan only, as follows::
let tl = the time taken for each complete scan of
the beams of both 8 and 9 in the y
direction, Et =the time taken for the beams 8 and 9 to
reach 0 in the y-scan in which it occurs,
t2 = the time taken from the beginning of the
total scan for the beams 8 and 9 to reach
the position 0,
n = the number of complete y-scans to reach
the position 0,
T = the total time taken to complete a scan
field (x = 0 X, y = 0 < Y), and
N = the total number of y-scans in a scan
field.
We have t2 = (n tl + Sot), therefore St = t2 - nt,
and
As the person 5 breathes and his chest rises and falls, the separation Ex will change in a regular way.
Changes in the condition of the person 5 can be monitored by storing in the store 12 the changes in the separation Ex which occur during one complete breathing cycle and comparing the stored data with later acquired data.
Movement of the body of the person 5 can be monitored by scanning the carriage 2 in the y-direction, storing data related to the changes in Ex as the light beams 8 and 9 are scanned over the body of the patient 5, and comparing data from one scan with data from a succeeding scan.
Whole body movement can be detected by scanning the carriage 2 in the x-direction as well as the y-direction and carrying out similar storage and comparison operations as before.
In order to distinguish between the image spots of the beams 8 and 9 and to avoid possible extraneous interference effects one or both of the beams 8 and 9 can be modulated.
When the body being monitored is a human being, as described above, it is preferable that the laser 1 is a low powered infra-red laser. It may be operated in either a continuous or pulsed mode.
Claims (11)
1. A method of monitoring displacements of a surface of a body comprising the operations of establishing a reference plane with respect to a body displacements of a surface of which are to be monitored, directing two beams of light at the body at an angle to each other, determining the separation between the points at which the two beams are incident upon the body and detecting temporal changes in the separation of the two positions at which the beams of light are incident upon the body thereby to monitor displacements of the surface of the body.
2. A method according to Claim 1 wherein the displacements of the surface of the body are due to changes in the size, configuration or position of the body.
3. An apparatus for monitoring displacements of an element of a surface of a body, comprising means for producing two beams of light and projecting them at an angle to each other onto an element of a surface of a body displacements of which are to be monitored, means for measuring the separation between the positions on the body at which the two beams of light are incident to determine a measure of the distance between the element of the surface of the body and a reference plane associated with the body, means for detecting temporal changes in the separation between the positions at which the two beams of light are incident upon the element of the body to determine displacements of the element of the surface of the body and means for indicating the displacements of the surface of the body.
4. Apparatus according to Claim 3 wherein there is included means for repeatedly scanning the two beams of light over the surface of the body in a direction normal to a plane in which the two beams of light lie, the scanning means being adapted to move in the said reference plane, means for storing data relating to measurements made during one scan of changes in the separation between the positions at which the beams of light are incident upon the body, means for comparing the stored data with corresponding data acquired in a succeeding scan of the beams of light over the body and means for providing an indication of any differences between the compared data sets thereby to monitor displacements of the surface of the body.
5. An apparatus according to Claim 4 wherein the scanning means is adapted to raster scan the two beams of light over an area of the body extending perpendicularly to the first direction of scan of the two beams of light over the surface of the body.
6. An apparatus according to any of Claims 3 to 5 wherein the two beams of light are derived from a single source.
7. An apparatus according to any of Claims 3 to 6 wherein at least one of the beams of light is modulated thereby to prevent optical interference between the two beams of light.
8. An apparatus according to any of Claims 3 to 7 wherein the two beams of light have a wavelength in the infra-red region of the electromagnetic spectrum.
9. An apparatus according to any of Claims 3 to 8 wherein the beams of light are beams of laser radiation.
10. A method for monitoring displacements of a surface of a body substantially as hereinbefore described and with reference to the accompanying drawing.
11. An apparatus for monitoring displacements of a surface of a body substantially as hereinbefore described and with reference to the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB919107740A GB9107740D0 (en) | 1991-04-11 | 1991-04-11 | Method of monitoring displacements |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9207780D0 GB9207780D0 (en) | 1992-05-27 |
| GB2254691A true GB2254691A (en) | 1992-10-14 |
Family
ID=10693108
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB919107740A Pending GB9107740D0 (en) | 1991-04-11 | 1991-04-11 | Method of monitoring displacements |
| GB9207780A Withdrawn GB2254691A (en) | 1991-04-11 | 1992-04-09 | Displacement monitoring system using two light beams |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB919107740A Pending GB9107740D0 (en) | 1991-04-11 | 1991-04-11 | Method of monitoring displacements |
Country Status (2)
| Country | Link |
|---|---|
| ES (1) | ES2643146T3 (en) |
| GB (2) | GB9107740D0 (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999001026A1 (en) * | 1997-07-02 | 1999-01-14 | Alfa Laval Agri Ab | A method and an apparatus for monitoring an animal |
| EP0980672A1 (en) * | 1998-08-18 | 2000-02-23 | Hiroshi Matsumoto | Diagnostic system and method for coronary artery disease |
| EP1175244A1 (en) * | 1999-04-07 | 2002-01-30 | Loma Linda University Medical Center | Patient motion monitoring system for proton therapy |
| WO2005020815A1 (en) * | 2003-09-03 | 2005-03-10 | Jean-Philippe Hermanne | Respiratory motion detection system |
| US7294112B1 (en) | 1999-05-13 | 2007-11-13 | Colin Dunlop | Motion monitoring apparatus |
| GB2438167A (en) * | 2006-05-19 | 2007-11-21 | Univ Teesside | Balance monitor |
| CN100536771C (en) * | 2007-08-14 | 2009-09-09 | 北京三维正基科技有限公司 | Three-dimensional mobility detecting instrument |
| US7696499B2 (en) | 2003-08-12 | 2010-04-13 | Loma Linda University Medical Center | Modular patient support system |
| US7789560B2 (en) | 2001-10-30 | 2010-09-07 | Loma Linda University Medical Center | Method and device for delivering radiotherapy |
| US9204824B2 (en) | 2008-12-11 | 2015-12-08 | Pneumacare Limited | Method and apparatus for monitoring an object |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111322953B (en) * | 2020-03-16 | 2024-06-21 | 中铁大桥科学研究院有限公司 | Sensing device for monitoring and positioning displacement of piston rod |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1458274A (en) * | 1973-01-15 | 1976-12-15 | Autech Corp | Apparatus for determining distance of a workpiece |
| GB2148488A (en) * | 1983-10-15 | 1985-05-30 | Vinten Ltd | A non-contacting mensuration system for measuring profiles |
| EP0227136A1 (en) * | 1985-11-19 | 1987-07-01 | Koninklijke Philips Electronics N.V. | Arrangement for optically measuring a surface profile |
| WO1990009560A1 (en) * | 1989-02-17 | 1990-08-23 | John Lysaght (Australia) Limited | Distance gauge |
-
1991
- 1991-04-11 GB GB919107740A patent/GB9107740D0/en active Pending
-
1992
- 1992-04-09 GB GB9207780A patent/GB2254691A/en not_active Withdrawn
-
2010
- 2010-10-06 ES ES10765482.4T patent/ES2643146T3/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1458274A (en) * | 1973-01-15 | 1976-12-15 | Autech Corp | Apparatus for determining distance of a workpiece |
| GB2148488A (en) * | 1983-10-15 | 1985-05-30 | Vinten Ltd | A non-contacting mensuration system for measuring profiles |
| EP0227136A1 (en) * | 1985-11-19 | 1987-07-01 | Koninklijke Philips Electronics N.V. | Arrangement for optically measuring a surface profile |
| WO1990009560A1 (en) * | 1989-02-17 | 1990-08-23 | John Lysaght (Australia) Limited | Distance gauge |
Cited By (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6418876B1 (en) | 1997-07-02 | 2002-07-16 | Alfa Laval Agri Ab | Method and an apparatus for monitoring an animal |
| WO1999001026A1 (en) * | 1997-07-02 | 1999-01-14 | Alfa Laval Agri Ab | A method and an apparatus for monitoring an animal |
| EP0980672A1 (en) * | 1998-08-18 | 2000-02-23 | Hiroshi Matsumoto | Diagnostic system and method for coronary artery disease |
| EP1175244A1 (en) * | 1999-04-07 | 2002-01-30 | Loma Linda University Medical Center | Patient motion monitoring system for proton therapy |
| EP1175244A4 (en) * | 1999-04-07 | 2004-09-15 | Univ Loma Linda Med | Patient motion monitoring system for proton therapy |
| US7294112B1 (en) | 1999-05-13 | 2007-11-13 | Colin Dunlop | Motion monitoring apparatus |
| US7883480B2 (en) | 1999-05-13 | 2011-02-08 | Colin Dunlop | Motion monitoring apparatus |
| US7789560B2 (en) | 2001-10-30 | 2010-09-07 | Loma Linda University Medical Center | Method and device for delivering radiotherapy |
| US8376613B2 (en) | 2001-10-30 | 2013-02-19 | Loma Linda University Medical Center | Method and device for delivering radiotherapy |
| US8083408B2 (en) | 2001-10-30 | 2011-12-27 | Loma Linda University Medical Center | Method and device for delivering radiotherapy |
| US8093569B2 (en) | 2003-08-12 | 2012-01-10 | Loma Linda University Medical Centre | Modular patient support system |
| US7746978B2 (en) | 2003-08-12 | 2010-06-29 | Loma Linda University Medical Center | Path planning and collision avoidance for movement of instruments in a radiation therapy environment |
| US7696499B2 (en) | 2003-08-12 | 2010-04-13 | Loma Linda University Medical Center | Modular patient support system |
| US7949096B2 (en) | 2003-08-12 | 2011-05-24 | Loma Linda University Medical Center | Path planning and collision avoidance for movement of instruments in a radiation therapy environment |
| US8184773B2 (en) | 2003-08-12 | 2012-05-22 | Loma Linda University Medical Center | Path planning and collision avoidance for movement of instruments in a radiation therapy environment |
| US8269195B2 (en) | 2003-08-12 | 2012-09-18 | Loma Linda University Medical Center | Patient alignment system with external measurement and object coordination for radiation therapy system |
| US8418288B2 (en) | 2003-08-12 | 2013-04-16 | Loma Linda University Medical Center | Modular patient support system |
| US8569720B2 (en) | 2003-08-12 | 2013-10-29 | Loma Linda University Medical Center | Patient alignment system with external measurement and object coordination for radiation therapy system |
| US8981324B2 (en) | 2003-08-12 | 2015-03-17 | Loma Linda University Medical Center | Patient alignment system with external measurement and object coordination for radiation therapy system |
| WO2005020815A1 (en) * | 2003-09-03 | 2005-03-10 | Jean-Philippe Hermanne | Respiratory motion detection system |
| GB2438167A (en) * | 2006-05-19 | 2007-11-21 | Univ Teesside | Balance monitor |
| CN100536771C (en) * | 2007-08-14 | 2009-09-09 | 北京三维正基科技有限公司 | Three-dimensional mobility detecting instrument |
| US9204824B2 (en) | 2008-12-11 | 2015-12-08 | Pneumacare Limited | Method and apparatus for monitoring an object |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9107740D0 (en) | 1991-05-29 |
| ES2643146T3 (en) | 2017-11-21 |
| GB9207780D0 (en) | 1992-05-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1293535C (en) | Apparatus for monitoring bloodstream | |
| US4180322A (en) | Interior measurement of enclosed spaces | |
| EP0751371B1 (en) | Installation and method for measuring rolling parameters by means of artificial vision on wheels of railway vehicles | |
| US4761072A (en) | Electro-optical sensors for manual control | |
| US7403638B2 (en) | Method and system for monitoring breathing activity of a subject | |
| KR940007111B1 (en) | Method and apparatus for the optical determination of surface profiles | |
| JP3738291B2 (en) | 3D shape measuring device | |
| EP2869067B1 (en) | Method and system for non-destructive inspection comprising a position determination | |
| US6757555B2 (en) | Ophthalmologic apparatus | |
| US5319442A (en) | Optical inspection probe | |
| GB2254691A (en) | Displacement monitoring system using two light beams | |
| US20050089206A1 (en) | Robust and low cost optical system for sensing stress, emotion and deception in human subjects | |
| US5291886A (en) | Apparatus for measuring blood flow | |
| KR20010083921A (en) | Method and system for predictive physiological gating of radiation therapy | |
| JPH0733998B2 (en) | Method and apparatus for optical quality monitoring of knitting machine needles | |
| US5319205A (en) | Proximity sensor for gamma camera | |
| JPH074928A (en) | Strain measuring apparatus | |
| US5748321A (en) | Position and orientation tracking system | |
| JP2003172609A (en) | Apparatus and method for measuring ellipticity, buckling, plane, and rolling parameters of railroad wheel | |
| JP2000513243A (en) | Apparatus and method for evaluating skin wrinkles in vivo | |
| JPS62264390A (en) | Visual sense recognizing device for supervisory robot | |
| JPH0833105A (en) | Slider wear amount-of-pantograph and deformed amount-of-shoe measuring system | |
| JPS62150111A (en) | Apparatus for measuring laser speckle strain | |
| EP4047303A1 (en) | Optical coherence tomography-based scanner calibration device and method for obtaining calibration information via a full area scan | |
| JPH0626972A (en) | Method for detecting gas leak position |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |