US4044377A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Video target locator
Assignee: Verizon Laboratories Inc
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Filing: 1976-04-28
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Granted: 1977-08-23
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Expires: 1996-04-28
Abstract
Abstract A closed circuit TV camera with a fixed focus lens, is used to measure the vertical displacement from and longitudinal distance from an industrial robot arm to checkered-row target pattern, i.e., a row of alternate black and white squares. The pattern is located in a fixed spatial relationship with a targeted object and is identified by the appearance of a burst of pulses in the video output during the horizontal scan. The vertical displacement of the target pattern from the optical axis of the camera is obtained by averaging the vertical deflection voltages, when the pattern is first acquired and when the pattern is just lost. The longitudinal distance to the target plane is obtained from the pulse repetition frequency within the burst, which increases linearly with distance. Harmonics of the fundamental burst frequency, which might result in ambiguity for far-to-near distance ratios exceeding two, are suppressed by a supplemental cylindrical lens which defocusses the image only along the line of scan without altering the top and bottom edge definition of the target.
Inventors
- 👤 Edwin R. Bowerman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:38
CPC Classifications
B; B25; B25J; B25J19/00; B25J19/02; B25J19/021; B25J19/023; G; G01; G01S; G01S13/00; G01S13/66; G01S13/70; G01S3/00; G01S3/78; G01S3/782; G01S3/785; G01S3/786; G01S3/7864
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
189 words
A target locator for measuring the distance of a target from a station point comprising: a. a target pattern of successive spaced-apart markings having a predetermined spatial relationship with the target; b. video signal generating means including i. a photosensitive medium, ii. optional means located at the station point for imparting a light-value related, electrostatically charged image of the target pattern onto the photosensitive medium when the target is in the viewing plane of the optical means, the image being perspectively scaled with respect to the pattern in at least one direction and in accordance with the target distance from the station point, iii. first scanning means for periodically directing a scanning beam over the imaged photosensitive material and along at least one scanning path having a generally parallel relationship with the direction of scaling, the video signal generating means being responsive to a scanned marking image to vary the video signal magnitude, whereby the duration of magnitude variation varies in accordance with the degree of perspective scaling; and c. means responsive to the varying duration to generate a signal indicative of the target distance from the station point.
Claim 2
Dependent Claim
189 words
A target locator for measuring the distance of a target from a station point comprising: a. a target pattern of successive spaced-apart markings having a predetermined spatial relationship with the target; b. video signal generating means including i. a photosensitive medium, ii. optional means located at the station point for imparting a light-value related, electrostatically charged image of the target pattern onto the photosensitive medium when the target is in the viewing plane of the optical means, the image being perspectively scaled with respect to the pattern in at least one direction and in accordance with the target distance from the station point, iii. first scanning means for periodically directing a scanning beam over the imaged photosensitive material and along at least one scanning path having a generally parallel relationship with the direction of scaling, the video signal generating means being responsive to a scanned marking image to vary the video signal magnitude, whereby the duration of magnitude variation varies in accordance with the degree of perspective scaling; and c. means responsive to the varying duration to generate a signal indicative of the target distance from the station point.
Claim 3
Dependent Claim
55 words
The target locator of claim 1 wherein the photosensitive medium is scanned in the general direction of the imaged markings; and the video signal generating means generates a pulse burst in response to the scanned markings, the pulses within the burst having a frequency which is related to the perspective scaling of the target image.
Claim 4
Dependent Claim
37 words
The target locator of claim 2 wherein the pulse frequency varies inversely with the pitch of the imaged markings, the pitch being perspectively scaled with respect to the target pattern pitch in accordance with the target distance.
Claim 5
Dependent Claim
17 words
The target locator of claim 2 including means for generating a burst having a generally sinusoidal waveform.
Claim 6
Dependent Claim
43 words
The target locator of claim 4 wherein the optical system includes means defocussing the pattern in a generally parallel direction with the scan to cause the video signal generating means to generate a generally sinusoidal video signal in response to the scanned markings.
Claim 7
Dependent Claim
24 words
The target locator of claim 5 wherein the optical system includes a cylindrical lens having its axis generally transverse to the direction of scanning.
Claim 8
Dependent Claim
129 words
The target locator of claim 1 including sweep voltage generating means for repeatedly deflecting the scanning beam in a direction essentially perpendicular to the scan path, the sweep voltage means being synchronized with the scanning means to define a field having a plurality of essentially parallel scan paths over the image area of the photoelectric medium; first means for sampling and holding the value of sweep voltage when the target marking images are initially detected in the field; second means for sampling and holding the value of sweep voltage when the target marking images are last detected in the field; and summing means responsive to the first and second sample and holding means for generating a signal indicative of the lateral displacement of the target from the station point.
Claim 9
Dependent Claim
171 words
A target locator for measuring the lateral displacement of a target from a longitudinal axis passing through a station point comprising: a. a target pattern of successive spaced-apart markings having a predetermined spatial relationship with the target; b. a video signal generating means including i. a photosensitive medium, ii. optical means located at the station point for imparting a light-value related, electrostatically charged image of the target pattern onto the photosensitive medium when the target is in the viewing plane of the optical means, iii. first means for periodically directing a scanning beam over the imaged photosensitive material and along at least one scanning path crossing the imaged markings; the video signal generating means being responsive to a scanned marking image to vary the video signal magnitude, c. means for moving the scanning beam in an essentially perpendicular direction to the scan path; d. means responsive to the video signal generating means to generate a signal indicative of the perpendicular displacement of the scanning beam when the pattern image is scanned.
Claim 10
Dependent Claim
171 words
A target locator for measuring the lateral displacement of a target from a longitudinal axis passing through a station point comprising: a. a target pattern of successive spaced-apart markings having a predetermined spatial relationship with the target; b. a video signal generating means including i. a photosensitive medium, ii. optical means located at the station point for imparting a light-value related, electrostatically charged image of the target pattern onto the photosensitive medium when the target is in the viewing plane of the optical means, iii. first means for periodically directing a scanning beam over the imaged photosensitive material and along at least one scanning path crossing the imaged markings; the video signal generating means being responsive to a scanned marking image to vary the video signal magnitude, c. means for moving the scanning beam in an essentially perpendicular direction to the scan path; d. means responsive to the video signal generating means to generate a signal indicative of the perpendicular displacement of the scanning beam when the pattern image is scanned.
Claim 11
Dependent Claim
84 words
The target locator of claim 8 including sweep voltage generating means for repeatedly deflecting the scanning beam in a direction essentially perpendicular to the scan path, the sweep voltage means being synchronized with the scanning means to define a field having a plurality of essentially parallel scan paths over the image area of the photoelectric medium; and first means for sampling the sweep voltage when the pattern marking images are detected in the field and generating a signal indicative of the lateral target displacement.
Claim 12
Dependent Claim
129 words
The target locator of claim 8 including sweep voltage generating means for repeatedly deflecting the scanning beam in a direction essentially perpendicular to the scan path, the sweep voltage means being synchronized with the scanning means to define a field having a plurality of essentially parallel scan paths over the image area of the photoelectric medium; first means for sampling and holding the value of sweep voltage when the target marking images are initially detected in the field; second means for sampling and holding the value of sweep voltage when the target marking images are last detected in the field; and summing means responsive to the first and second sampling and hold means for generating a signal indicative of the lateral displacement of the target from the station point.
Claim 13
Independent Claim
80 words
A method for locating a targeted object with respect to a station point comprising the steps of: mounting a video camera at the station point; placing a target pattern of successive spaced-apart markings in a fixed spactial relationship with the targeted object; bringing the target pattern within the viewing field of the camera to cause the camera to generate a series of pulses during its scan of the pattern, and generating a first distance signal related to the pulse frequency.
Claim 14
Independent Claim
80 words
A method for locating a targeted object with respect to a station point comprising the steps of: mounting a video camera at the station point; placing a target pattern of successive spaced-apart markings in a fixed spactial relationship with the targeted object; bringing the target pattern within the viewing field of the camera to cause the camera to generate a series of pulses during its scan of the pattern, and generating a first distance signal related to the pulse frequency.
Claim 15
Dependent Claim
28 words
The method of claim 11 including the step of orienting the target pattern so that the "fast" scan direction of the camera lies generally transverse to the markings.
Claim 16
Dependent Claim
74 words
The method of claim 12 including the additional steps of detecting a first value of the vertical deflection voltage related to the scan line at which the target pattern is initially detected; detecting a second value of the vertical deflection voltage related to the scan line at which the target is last detected; and summing the two values to obtain a signal indicative of the lateral displacement of the target from the robot arm.
Claim 17
Dependent Claim
33 words
The method of claim 13 including the step of defocussing the camera along the optical axis in the "fast" scan direction to generate sinusoidal pulses in response to the scanning of the pattern.
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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) | 1980-08-22 | 1981-02-21 | 1981-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-22 | 1985-02-21 | 1985-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-22 | 1989-02-21 | 1989-08-23 | $7700.00 | Window Closed / Lapsed |