Optics: measuring and testing – By polarized light examination – With light attenuation
Reexamination Certificate
1999-06-15
2001-07-31
Font, Frank G. (Department: 2877)
Optics: measuring and testing
By polarized light examination
With light attenuation
C356S370000, C356S389000, C356S226000, C356S233000
Reexamination Certificate
active
06268918
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a three-dimensional input device for measuring the shape of an object by projecting a reference light on the object.
2. Description of the Related Art
Non-contact type three-dimensional input devices which are known as rangefinders are used for data input to computer graphics (CG) systems and computer-aided design (CAD) systems, physical (body) measurement, robot visual recognition and the like because these devices are capable of high speed measurement compared to contact-type devices.
The slit projection method (also referred to as “light-section method”) is known to be suitable as a measurement method for rangefinders. This method optically scans an object to obtain a distance image (three-dimensional image), and is one type of dynamic measuring method for sensing an object by illumination with a specific reference light. The distance image is a collection of pixels expressing a three-dimensional position at a plurality of parts of an object. In the slit projection method, a slit light having a linear band-like projection beam cross section is used as a reference light.
A two-dimensional color photography function is used in the rangefinder. A photographed two-dimensional image is displayed on a monitor via an internal or external display device, and a user uses the reference information when determining the field angle of the three-dimensional measurement. Two-dimensional photography is accomplished at the same field angle as three-dimensional measurement, and the obtained two-dimensional image is combined with the three-dimensional data and either output or stored as the measurement result. When viewing the two-dimensional image, a user can readily confirm the measured object, and the two-dimensional image may be used for correction or processing of the three-dimensional data.
In a conventional rangefinder, an aperture is not provided in the light-receiving optical path so as to allow as much reference light reflected by an object as possible to enter the photoreceptive surface of the photoelectric converter. Two-dimensional photography is accomplished by automatic exposure control via an electronic shutter, and three-dimensional measurement is accomplished by optimizing the amount of light entering the photoreceptive surface by adjusting the projection intensity of the reference light. A disadvantage of this construction is that in two-dimensional photography the depth of the field cannot be increased, and the aberration produced by the lens cannot be ignored. This disadvantageously produces a small S/N ratio. In three-dimensional measurement, when the projection intensity is reduced, the effect of the background light increases so as to reduce the measurement accuracy.
SUMMARY AND OBJECTS
An object of the present invention is to increase the quality of the output data by setting a suitable exposure and depth of field for two-dimensional photography and three-dimensional measurement, respectively.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the apparatus of the this invention comprises a projector which projects a reference light on an object; an image sensor which senses an image of the object and converts the image into electrical signals; and a controller for controlling the projector and the image sensor, wherein when the controller prevents the projector from projecting the reference light, a two-dimensional image input is received by the image sensor and converted into a two-dimensional image electrical signals, and when the controller instructs the projector to project the reference light, a three-dimensional image input is received by the image sensor and converted into a three-dimensional image electrical signals.
In a further aspect of the present invention the apparatus hereof also comprises a processing unit which measures the shape of the object based on the three dimensional image electrical signals.
In yet a further aspect of the present invention the apparatus hereof also comprises an aperture that restricts the passage of entering light; and an aperture controller for independently setting an aperture value for the aperture when receiving a two-dimensional image input, and setting an aperture value for the aperture when receiving a three-dimensional image input.
In a further aspect of the present invention the apparatus hereof also comprises a first light receiving device for two-dimensional image input; a second light receiving device for three-dimensional input; a lens system which receives light from the object, the lens system being common to the first light receiving device and the second light receiving device; and an optical member for distributing the light received by the lens system to the first light receiving device and the second light receiving device, wherein the aperture is disposed within the optical path between the lens system and the optical member.
In a further aspect of the present invention the apparatus hereof wherein the projector projects the reference light in the form of a slit, and the reference light scans the object so as to move one pixel pitch on a surface of the image sensor in a sampling cycle.
In a further aspect of the present invention the apparatus hereof also comprises a memory for storing a plurality of frames of an image, each frame of the plurality of frames having a plurality of lines of an image with a line in common with all other frames of the plurality of frames, and wherein the processing unit determines the time center Npeak of the line in common with all other frames of the plurality of frames.
In yet a further aspect of the present invention the apparatus hereof also comprises a flicker detector which detects a change frequency in light received by the image sensor, and wherein the controller controls the image sensor to sense frames of an image at a frequency which is a multiple of the detected change frequency.
To further achieve the foregoing and other objects of the present invention, as embodied and broadly described herein, the method of the this invention comprises a method of detecting an image in an image detecting device including a projector which projects a reference light on an object, an image sensor which senses an image of the object, and a controller which controls the projector and the image sensor, the method comprising the steps of: sensing a two-dimensional image input by the image sensor; sensing a three-dimensional image based on the reference light; making a three-dimensional measurement; and forming an image based on the two-dimensional image and the three-dimensional image.
In an aspect of the present invention the step of sensing a two-dimensional image further comprises the steps of: setting an aperture value of an aperture through which the received two-dimensional and three-dimensional images pass; and capturing the received two-dimensional image and converting the received two-dimensional image into electrical signals.
In a further aspect of the present invention the method hereof also comprises the steps of: a preliminary measurement; and a second sensing of two-dimensional images, wherein said steps of preliminary measurement and second sensing of two-dimensional images occur after the step of sensing of two-dimensional images and before the step of sensing a three-dimensional image.
In a further aspect of the present invention the step of preliminary measurement further comprises the steps of: opening the an aperture through which the received two-dimensional and three-dimensional images pass; projecting a minimum intensity of the reference light by the projector; setting a provisional aperture value based on a measured value of the light received through the aperture at the minimum intensity of the reference light; projecting a maximum intensity of the reference light by the projector; and setting the provisional aperture value as the aperture value if a measured value of the light
Ide Eiichi
Kamon Koichi
Miyazaki Makoto
Norita Toshio
Tanabe Hideki
Font Frank G.
McDermott & Will & Emery
Minolta Co. , Ltd.
Ratliff Reginald
LandOfFree
Three-dimensional input device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Three-dimensional input device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Three-dimensional input device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2436877