US3883689A
Expired / Lapsed
US
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Servo-controlled intravital microscope system
Assignee: National Aeronautics and Space Administration
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Filing: 1973-09-04
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Granted: 1975-05-13
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Expires: 1993-09-04
Abstract
Abstract This disclosure relates to a microscope system for viewing an area of a living body tissue that is rapidly moving, by maintaining the same area in the field-of-view and in focus. A focus sensing portion of the system includes two video cameras at which the viewed image is projected, one camera being slightly in front of the image plane and the other slightly behind it. A focus sensing circuit for each camera differentiates certain high frequency components of the video signal and then detects them and passes them through a low--pass filter, to provide DC focus signal whose magnitudes represent the degree of focus. An error signal equal to the difference between the focus signals, drives a servo that moves the microscope objective so that an in-focus view is delivered to an image viewing/recording camera. The lens system includes a moveable microscope objective which collimates rays from the object, and a transfer lens much larger than the objective lens for focusing the collimated rays onto the target plane of the viewing camera.
Inventors
- 👤 Momtaz N Mansour
- 👤 Harold J Wayland
- 👤 Carl P Chapman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:27
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/60; H04N23/67; H04N23/673
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
233 words
Microscope apparatus for viewing a moving area of an object comprising: lens means positioned behind the object; lens moving means for moving the lens means; viewing means positioned behind the lens means; first and second video camera means positioned behind the lens means for generating video signals, the first camera means positioned slightly behind the image plane of the lens means and the second camera means positioned slightly in front of the image plane of the lens means; beamsplitter means positioned behind the lens means and in front of the viewing means and the video camera means, to pass light to the viewing means and each camera means; first and second focus sensor circuits respectively connected to the outputs of the video camera means, each focus circuit including a first electrical filter for passing only predetermined high frequency components of the video signal, low pass filter means for integrating signals representing the high frequency components, and means for coupling the first filter to the low pass filter means; difference circuit means coupled to the outputs of the first and second focus means for generating a signal value representing the difference between the outputs of the low pass filter means of the two focus circuits; and servo means coupled to said difference means for energizing the lens moving means to move the lens means with a directional component toward and away from the object.
Claim 2
Dependent Claim
233 words
Microscope apparatus for viewing a moving area of an object comprising: lens means positioned behind the object; lens moving means for moving the lens means; viewing means positioned behind the lens means; first and second video camera means positioned behind the lens means for generating video signals, the first camera means positioned slightly behind the image plane of the lens means and the second camera means positioned slightly in front of the image plane of the lens means; beamsplitter means positioned behind the lens means and in front of the viewing means and the video camera means, to pass light to the viewing means and each camera means; first and second focus sensor circuits respectively connected to the outputs of the video camera means, each focus circuit including a first electrical filter for passing only predetermined high frequency components of the video signal, low pass filter means for integrating signals representing the high frequency components, and means for coupling the first filter to the low pass filter means; difference circuit means coupled to the outputs of the first and second focus means for generating a signal value representing the difference between the outputs of the low pass filter means of the two focus circuits; and servo means coupled to said difference means for energizing the lens moving means to move the lens means with a directional component toward and away from the object.
Claim 3
Dependent Claim
71 words
The apparatus described in claim 1 including: manually adjustable bias means for generating a variable bias signal; and means for coupling the bias means to the servo means, to add the bias signal to the difference between the outputs of the low pass filter means of the first and second focus circuits, whereby to enable slight change of the distance between the objective lens and object even as the object moves.
Claim 4
Dependent Claim
25 words
The apparatus described in claim 1 including: manually operable means coupled to one of said video cameras for varying its distance from the lens means.
Claim 5
Dependent Claim
31 words
The apparatus described in claim 1 wherein: said means, in each focus circuit, for coupling the first filter to the low pass filter means, includes a differentiating circuit and a detector.
Claim 6
Dependent Claim
80 words
The apparatus described in claim 1 wherein: said lens means includes a microscope objective lens positioned behind the object at a distance equal to the focal length of the objective lens, and a transfer lens positioned in front of the viewing means by a distance equal to the focal length of the transfer lens; said transfer lens is held stationary; and said lens moving means is coupled to the objective lens to move it while the transfer lens remains stationary.
Claim 7
Dependent Claim
183 words
Microscope apparatus for viewing a moving area of an object comprising: a microscope objective lens mounted for movement at least axially toward and away from the object; a transfer lens mounted behind the objective lens; beamsplitter means mounted behind the transfer lens; first and second video cameras mounted behind the beamsplitter means, at distances from the transfer lens respectively slightly greater and slightly less than the focal length of the transfer lens; first and second focus circuits respectively connected to the first and second cameras, each circuit including a bandpass filter for passing only predetermined frequency components of the video signal from its corresponding camera, a differentiator for generating the time derivative of the high frequency components, and a detector and low frequency filter circuit for integrating the derivative signal; a difference circuit connected to the two focus sensing circuits; a servo circuit for generating a drive signal dependent upon the output of the difference circuit; and a transducer connected to the servo circuit and mechanically coupled to the microscope objective lens, for moving the objective lens toward and away from the object.
Claim 8
Dependent Claim
183 words
Microscope apparatus for viewing a moving area of an object comprising: a microscope objective lens mounted for movement at least axially toward and away from the object; a transfer lens mounted behind the objective lens; beamsplitter means mounted behind the transfer lens; first and second video cameras mounted behind the beamsplitter means, at distances from the transfer lens respectively slightly greater and slightly less than the focal length of the transfer lens; first and second focus circuits respectively connected to the first and second cameras, each circuit including a bandpass filter for passing only predetermined frequency components of the video signal from its corresponding camera, a differentiator for generating the time derivative of the high frequency components, and a detector and low frequency filter circuit for integrating the derivative signal; a difference circuit connected to the two focus sensing circuits; a servo circuit for generating a drive signal dependent upon the output of the difference circuit; and a transducer connected to the servo circuit and mechanically coupled to the microscope objective lens, for moving the objective lens toward and away from the object.
Claim 9
Dependent Claim
217 words
Microscope apparatus for viewing a moving area of an object comprising: an objective lens behind the object and mounted to move axially toward and away from the object as well as laterally; a transfer lens of larger diameter than the objective lens and mounted behind the objective lens; viewing means mounted behind the transfer lens at a distance therefrom approximately equal to the focal length of the transfer lens, for detecting an image substantially focused at the viewing means; and lens moving means responsive to changes in the focus and position of the image at the viewing means for moving the objective lens, with respect to the transfer lens, laterally as well as axially towards and away from the object, to compensate for lateral and axial movements of the object area; said viewing means including A video camera for generating a video electrical signal, an electrical filter for passing only predetermined frequency components of the video signal, a differentiating circuit coupled to the filter, a detection means, a low pass filter for integrating the output of the detecting means, and means for generating a control signal of a magnitude dependent upon the output of the low pass filter means; and said lens moving means being constructed to move the lens axially in response to the control signal.
Claim 10
Dependent Claim
217 words
Microscope apparatus for viewing a moving area of an object comprising: an objective lens behind the object and mounted to move axially toward and away from the object as well as laterally; a transfer lens of larger diameter than the objective lens and mounted behind the objective lens; viewing means mounted behind the transfer lens at a distance therefrom approximately equal to the focal length of the transfer lens, for detecting an image substantially focused at the viewing means; and lens moving means responsive to changes in the focus and position of the image at the viewing means for moving the objective lens, with respect to the transfer lens, laterally as well as axially towards and away from the object, to compensate for lateral and axial movements of the object area; said viewing means including A video camera for generating a video electrical signal, an electrical filter for passing only predetermined frequency components of the video signal, a differentiating circuit coupled to the filter, a detection means, a low pass filter for integrating the output of the detecting means, and means for generating a control signal of a magnitude dependent upon the output of the low pass filter means; and said lens moving means being constructed to move the lens axially in response to the control signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |