US3706495A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of measuring the velocity of a small moving object
Assignee: Individual
•
Filing: 1970-07-31
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Granted: 1972-12-19
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Expires: 1990-07-31
Abstract
Abstract The velocity of a small moving particle is determined by allowing the particle to pass between a laser light source and a photographic film or plate. The laser is caused to illuminate the photographic film with coherent plane-wave light for a short interval of time while the particle is between the laser and the film to thereby record a hologram pattern on the film. The duration of the exposure time is made such that the particle moves a noticeable distance during such exposure time. The exposed photographic film is developed and the velocity of the particle is determined by analysis of the developed film. In one embodiment, the velocity is determined by scanning the film with a microdensitometer and measuring the separation distance between phase reversal points on the microdensitometer trace. In another embodiment, the velocity is determined by reconstructing an image from the hologram pattern on the film and measuring the path length of the particle in the reconstructed image.
Inventors
- 👤 William P Dotson Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:05
CPC Classifications
G; G03; G03H; G03H1/00; G01; G01P; G01P5/00; G01P5/001; G01P5/18; G01P5/20; G03B; G03B15/00; G03B15/16; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
202 words
A method of measuring the velocity of a small moving object comprising: allowing the object to pass between a coherent light source and a photographic film; causing the light from said light source to travel in a plane wave in a direction substantially perpendicular to the plane of the photographic film; causing the light source to illuminate the film for a short interval of time while the object is between the source and the film to thereby record a hologram pattern on the film; making the exposure time of such duration that the object moves a distance greater than d but not greater than 10d during the exposure time and wherein the shortest distance between the object and the plane of the film during the exposure time is equal to or greater than R2/( but is not greater than 100d2/ lambda , where R denotes the path length of the object during the exposure time, d denotes the mean dimension of the object in the direction of movement and lambda denotes the wavelength of the light from the light source; developing the photographic film; and analyzing the resulting hologram pattern on said film to determine therefrom the velocity of the moving object.
Claim 2
Independent Claim
202 words
A method of measuring the velocity of a small moving object comprising: allowing the object to pass between a coherent light source and a photographic film; causing the light from said light source to travel in a plane wave in a direction substantially perpendicular to the plane of the photographic film; causing the light source to illuminate the film for a short interval of time while the object is between the source and the film to thereby record a hologram pattern on the film; making the exposure time of such duration that the object moves a distance greater than d but not greater than 10d during the exposure time and wherein the shortest distance between the object and the plane of the film during the exposure time is equal to or greater than R2/( but is not greater than 100d2/ lambda , where R denotes the path length of the object during the exposure time, d denotes the mean dimension of the object in the direction of movement and lambda denotes the wavelength of the light from the light source; developing the photographic film; and analyzing the resulting hologram pattern on said film to determine therefrom the velocity of the moving object.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the object moves in a plane substantially parallel to the plane of the photographic film.
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein the light source is a laser.
Claim 5
Dependent Claim
42 words
The method of claim 3 wherein a collimator device is located intermediate the laser and the region of movement of the object for collimating said light for illuminating both the object and the photographic film with light of a plane wave character.
Claim 6
Dependent Claim
24 words
The method of claim 3 wherein the exposure time is determined by using a pulsed laser and providing same with the proper pulse width.
Claim 7
Dependent Claim
27 words
The method of claim 3 wherein the exposure time is determined by a shutter mechanism disposed across the light path intermediate the laser and the photographic film.
Claim 8
Dependent Claim
35 words
The method of claim 1 wherein the analysis of the hologram pattern comprises the steps of: making microdensitometer measurements across the developed film; and determining from the microdensitometer measurements the velocity of the moving object.
Claim 9
Dependent Claim
61 words
The method of claim 7 wherein the microdensitometer measurements are made by scanning the developed film along a given line with a microdensitometer and recording the microdensitometer signal to provide a microdensitometer trace representing the variation in film density along such line and wherein the velocity is determined by measuring the separation distance between phase reversal points on the microdensitometer trace.
Claim 10
Dependent Claim
39 words
The method of claim 1 wherein the analysis of the hologram pattern comprises the steps of: reconstructing an image by illuminating the developed film with coherent light; and determining from the reconstructed image the velocity of the moving object.
Claim 11
Dependent Claim
22 words
The method of claim 9 wherein the velocity is determined by measuring the path length of the object in the reconstructed image.
Claim 12
Independent Claim
227 words
A method of measuring the velocities of individual particles in a stream of many small moving particles comprising: allowing the stream of particles to pass between a coherent light source and a photographic film; causing the light from said light source to travel in a plane wave in a direction substantially perpendicular to the plane of the photographic film; causing the light source to illuminate the film for a short interval of time while the particles are between the source and the film to thereby record a hologram pattern on the film; making the exposure time of such duration that each particle moves a distance greater than d but not greater than 10d during the exposure time and wherein the shortest distance between the object and the plane of the film during the exposure time is equal to or greater than R2/ lambda but is not greater than 100d2/ lambda , where R denotes the path length of the object during the exposure time, d denotes the mean dimension of the object in the direction of movement and lambda denotes the wavelength of the light from the light source; developing the photographic film; reconstructing an image by illuminating the developed film with coherent light; measuring the path lengths of the individual particles in the reconstructed image; and determining the velocities of the individual particles from said measurements.
Claim 13
Independent Claim
227 words
A method of measuring the velocities of individual particles in a stream of many small moving particles comprising: allowing the stream of particles to pass between a coherent light source and a photographic film; causing the light from said light source to travel in a plane wave in a direction substantially perpendicular to the plane of the photographic film; causing the light source to illuminate the film for a short interval of time while the particles are between the source and the film to thereby record a hologram pattern on the film; making the exposure time of such duration that each particle moves a distance greater than d but not greater than 10d during the exposure time and wherein the shortest distance between the object and the plane of the film during the exposure time is equal to or greater than R2/ lambda but is not greater than 100d2/ lambda , where R denotes the path length of the object during the exposure time, d denotes the mean dimension of the object in the direction of movement and lambda denotes the wavelength of the light from the light source; developing the photographic film; reconstructing an image by illuminating the developed film with coherent light; measuring the path lengths of the individual particles in the reconstructed image; and determining the velocities of the individual particles from said measurements.
References Cited (Backward Citations)
US3520610A
Cited
US3563652A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-12-19 | 1976-06-19 | 1976-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-19 | 1980-06-19 | 1980-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-19 | 1984-06-19 | 1984-12-19 | $7700.00 | Window Closed / Lapsed |