Optics: measuring and testing – By polarized light examination – With light attenuation
Patent
1999-02-09
2000-08-01
Font, Frank G.
Optics: measuring and testing
By polarized light examination
With light attenuation
25055938, G01B 1114, G01V 800
Patent
active
060974915
DESCRIPTION:
BRIEF SUMMARY
This application is the national phase under 35 U.S.C. .sctn.371 of prior PCT International Application No. PCT/EP97/01783 which has an International filing date of Apr. 10, 1997 which designated the United States of America, the entire contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for measuring the co-ordinates of one or several retroflectors applied on an object, in which light from an illumination unit reaches at least one retroreflector via a beam splitter, light reflected back by the retroreflector is separated from the illumination beam path at the beam splitter and the light impinges upon a detector unit with which the impinging of the detected light spot can be determined.
2. State of the Art
A number of processes have been developed for determining optical co-ordinates based on optical marking of the object and determining the position of the optical marking from one or multiple reference points.
Depending on the type of marking these processes can be divided into 2 classes:
A. Processes in which the marking occurs only optically (see A-document DE 4325542). The to-be-measured object does not need to be especially treated. A light beam having a known beam course illuminates the object and is scattered on the surface of the object. The scattering surface of the object represents the marking and is imaged on a position-resolving or image-giving sensor. These processes are distinguished by the necessity of imaging the illuminated surface of the to-be-measured object on the sensor. Measuring is usually not possible in the case of reflecting objects, because radiation falls on the detector only if the detector, the illumination and the surface of the object are in a particular angle position in relation to each other. Retroreflecting objects can principally not be measured, because the illuminating beam path is reflected back within itself .
B. Processes for measuring optically particular points. In these processes, a special marking is applied on or in the to-be-measured object if the object itself does not possess the special optical property.
Common markings are: non-contact measurement is simpler than you think"). to the surroundings). publication SMART310).
Measuring according to A and measuring according to the markings 1 and 2 occurs via an image of the luminous respectively illuminated surface of the object or the marking on position-resolving respectively image-giving sensors. For these processes, an imaging optic has to be utilized between the marking and the object. Due to this, the following problems can arise: of focusing respectively reflecting surfaces in the measuring field.
In measuring systems according to B.1., a luminous element has to be attached to each interesting point of the object. The element has to illuminate the surrounding space in such a manner that sufficient light falls on the sensor so that the image of the element can be distinctly differentiated from the surroundings in the sensor plane. To do so, the element has to be supplied with energy. This means that either an energy carrier has to be applied, and the size of the element becomes relatively large, or supply cables have to be laid to the object. The costs of applying them to a to-be-measured object are relatively big.
In the processes based on imaging a scattering marking, the contrast between the image of the surrounding and the image of the marking has to be obtained by suitably intensive respectively selective illumination of the measured area. With this type of measuring, in circumstances, considerable measuring errors can occur if there are reflecting or shiny surfaces in the measuring field. Furthermore, strong illumination of the measuring area is often only obtainable with relatively great energy expenditure.
On the other hand, very efficient are processes based on locating a retroreflector, because it practically reflects the entire light impinging on it within itself respectively offset in parall
REFERENCES:
patent: 4123165 (1978-10-01), Brown et al.
patent: 4171910 (1979-10-01), Derderian et al.
patent: 4736247 (1988-04-01), Graham et al.
patent: 4763361 (1988-08-01), Honeycutt et al.
Font Frank G.
Fraunhofer-Gesellschaft zur Forderung der Angewandten Forschung
Smith Zandra V.
LandOfFree
Device for measuring the co-ordinates of one or several retroref does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for measuring the co-ordinates of one or several retroref, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for measuring the co-ordinates of one or several retroref will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-669358