MXPA06005438A - Proximity detector - Google Patents

Abstract

Apparatus for detecting proximity between a first object (target object) and a second object (reference object), comprising a light source (1) and a light detector (3) adapted to receive resulting back-scattered light from the reference object when illuminated from the light source (1), whereby the intensity of hack -scattered light to the light detector (3) is utilized as a measure of said proximity. The target object (2) comprises an optical device (4) having a focal plane (7) and being adapted to be illuminated by the light source (1). The axes of the light rays from the light source (1) and the back-scattering to the light detector (3) have mutually closely adjacent and substantially parallel or coincident portions. Said proximity corresponds to a distance (relative position) between the target object (2) and the reference object (6, 8) wherein the reference object is located substantially at the focal plane.

Description

PROXIMITY DETECTOR DESCRIPTION OF THE INVENTION The invention relates to an apparatus that can detect when one or more objective objects are close to their respective reference surfaces or reference objects. The invention also relates to a steering system that can cooperate with the apparatuses and can determine when one or more target objects are in proximity to their respective reference surfaces or reference objects. In addition, the invention relates to a method for determining when one or more target objects are in proximity to their respective reference surfaces or reference objects. At present there are several known methods for determining whether a target object is in the vicinity of a reference surface or reference object. The detection of proximity is of interest, among other things, in industrial, automotive and aeronautical systems. By means of proximity detectors, systems can report their position in relation to the reference objects and report conditions, such as to determine the condition of valves (closed, open) Ref .: 172276 provided with such proximity detectors. In automatic or autonomous systems the systems can by themselves respond to the conditions of proximity sensors and other sensors, changing the acceleration or speed direction, and possibly carrying out a series of different operations that depend on the state of the system as a whole.

In general proximity detectors have the property that there is no requirement for physical contact between the objective object and the reference object in order to determine that both are close to each other. In some cases it is also decisive that there is no requirement for physical contact between the detector system and one or more of those two objectives, and that the proximity detection is consequently obtained by remote sensing. It can also be decisive that the equipment in these two objects does not require any electrical power or another. In addition, it can be decisive that the team is underweight. It can also be decisive that the equipment is simple and economical to manufacture. In many cases it may be important that the equipment does not require any maintenance. Furthermore, it is often important that the equipment or measurement method has no influence on the target object or environments, for example by altering electric or magnetic fields. In the use of medical equipment there will be a strict requirement that the equipment does not harm the patient. The present invention satisfies all the above objects. A number of different principles of proximity sensors are known, for example based on the measurement of the ultrasound propagation distance, etc. (US6114950, DE3235028, US5144593), triangulation with visible or invisible light (09219984), optical differential phase measurement (US4752799), fiber optic sensors (US6498654), laser-based principles (DE2448898), magnetic principles (US6127821, US2003173957 ) , etc. US 5,200,604 discloses an optical proximity detector for a probe in a laser scalpel device. The proximity detector consists of a light source, a light conductor that directs the light towards an exit opening and a light detector that receives light through a light conductor towards an opening in the vicinity of the exit opening . The proximity to a reference surface is calculated from the reflected light. The purpose is to prevent the activation of a laser scalpel before there is contact with the tissue in which it is to be cut. US 4,991,509 describes a method and an apparatus for determining the separation between an object and a reference surface. The proximity detector consists of a light source, a light conductor that directs light to an exit aperture, and a light detector that receives light through the light conductor towards an aperture in the vicinity of the exit aperture. The two openings are spaced apart from one another in such a way that the emitted light cone overlaps to a greater or lesser extent the field of view captured by the light detector through the entry opening. The proximity to a reference surface is calculated from the intensity of reflected light. The two US 5 patents, 200,604 and US 4,991,509 describe the proximity detection by means of a principle in which the source and the detection have some mutual separation in such a way that the light cone of the light source and the field of view of the light detector will cover a common volume or a common area in the reference object, which will vary depending on the spacing between the objective object and the reference surface, thus representing a variable backscattering light intensity. In contrast to the present invention, these patents do not include any lens or curved mirrors with associated focal lengths that define proximity detection. The patents do not describe any device where the cone of light of the light source and the field of view of the light detector are coincident; on the contrary, a specific lateral separation between the two openings is required in such a way that the light cone and the light detector will have a partially overlapping coverage area which in turn depends on the distance to the reference surface and where it is located. Variable overlap area provides a variable backscattering light intensity that can be measured in the light detector. Therefore, a prerequisite in the two patents is a lateral distance between the entry opening and the exit opening in order for the devices to operate properly, while the present invention does not include the requirement that the entry opening and the outlet opening must be separated by a lateral distance.

In the present invention, said target object and the reference surface or reference object will be illuminated completely or partially by light, and this light has a spectrum inside or outside the visible range. The light detector can be a camera with subsequent analog and / or digital signal processing and / or digital image processing, or in a simpler mode it can be composed of one or more photo optical detectors with detection electronics associated This illumination can be pulsed or modulated in order to distinguish it from other illumination, and such modulation can also be synchronized with the detection of light. The invention will now be explained in more detail with reference to the appended figures, in which: Figure 1 illustrates one embodiment of the proximity detector. Figure 2 illustrates one embodiment of a proximity detector system having a common light source and light detection common with a camera and a computer or similar digital system for image acquisition, data processing, presentation, communication and operation of related software. Figure 3 illustrates a mode in which the light source is associated with the objective object. Figures 4 to 7 show various modifications of modalities according to the invention. Figure 1 shows a mode of the proximity detector. The light source 1 and the light detector 3 will have the axes as close as possible and as parallel as possible directed towards the objective object 2, while the < The objective object will be provided with a convex lens 4 (consisting of one or more lens elements, or alternatively a sphere or cylindrical rod) or a concave mirror (or a group of several mirrors with different curvatures), representing a specific focal length 7. Proximity detection is obtained when such a lens-mirror configuration in that objective object has a distance to such a reference surface or reference object that corresponds to this specific focal length 7, while the light is backscattered to a small degree through the Thickness of the lens over a greater distance 8 or a shorter distance 6. The reference surface 6, 7, 8, or the reference object should have some reflectability in such a way that not all incident light will be absorbed. Under such conditions the proximity between the target object and the reference surface or reference object can be detected in that illuminated lens-mirror array, since the incident light from the illumination source through the mirror-lens array is back-scattered of the reference surface or reference object towards that detector through the lens-mirror array because the distance between the lens-mirror array of the objective object and the reference surface is corresponding. By comparing the level of light intensity with a fixed or dynamic reference level, it is possible to detect that this level of light intensity under these mentioned conditions has become greater. The reference level can be static, dynamic or adjustable based on measurements. If the illumination is modulated and / or also has a synchronized detection, there will be a reduced possibility for other random illumination to result in a false detection. As "receiver" (light detector) a human eye (the vision of the operator) can be contemplated instead of a camera or the like, the receiver arrangement being in such a case designed to cooperate with an eye of the operator or user. In a preferred version the proposed solution will have only that mirror-lens array or device mounted on the target object, while the illumination source and the detector are separated from the target object and the reference object. Furthermore, this light source and this detector can be separated from each other, as long as the detector is placed in the axis of the back-scattered light of the mirror-lens array. In another preferred version as illustrated in figure 3, the light source 1 can be located on the objective object 2 while the light detector 3 can be located in another stationary or moving point. In a third preferred version as illustrated in FIG. 4, the detector 3 is located on the objective object 2 while the illumination source is located at another stationary or moving point. In a fourth preferred version as illustrated in FIG. 5 both the detector and the light source are located on the target object. In a fifth preferred embodiment as illustrated in FIG. 6, a concave mirror 4 is used as an optical focusing element located on the objective object 2. In a sixth preferred embodiment as illustrated in FIG. 7, a concave mirror 4 is used. as a focusing element located on the objective object 2, and the objective object is placed on the opposite side of a diffusion screen in relation to the light source and the detector. It is also possible to change this direction axis of the light detector in relation to the direction of the axis of the light source, by means of an additional mirror and / or other optical elements. See variants 3a-14 in figure 3. A mode of a system for proximity detection and / or also position determination 11 for use together with one or more devices 9 that make it possible to detect when one or more target objects are in the vicinity of their respective reference surfaces 6, 7, 8 or reference objects 6, 7, 8 is illustrated in Figure 2. In this embodiment there is a plurality of proximity detectors having a common light source and a detection of common light through a camera, and a computer or similar digital system for image acquisition, data processing, presentation, communication and implementation of related software. It will often be necessary to process analog and / or digital signals of the image pixels in order to obtain reliable proximity detection, where different reference levels are also used and can also be estimated. The invention relates to the general principle of proximity detection. As described above, proximity sensors can have significant industrial possibilities in various fields of use. The application of new low-cost camera technology and other modern solid-state optical sensors together with modern lighting sources such as lasers, laser diodes and light-emitting diodes, etc. that can be modulated or pressed reliably, give the principles a great potential for use and benefits. The uses can be where the dimensions to be monitored are large or where the distances are in the range of millimeters or microns. In general, the invention can be used together with means for determining the lateral position and determining the orientation of target objects. The present invention can be used in conjunction with the positioning and orientation principles of Norwegian Patent No. 311740 and PCT Patent PCT / NO01 / 00369 in general cases where it is desired to detect the positions and / or also the orientations of one or more objects objective in the observation plane and at the same time also determines the proximity to one or more reference objects and / or also determines several details with respect to the condition of the objects. The PCT patent PCT / NO01 / 00369 also generally covers the operation of determining the position and / or also to find the orientation of one or more marked target objects in an area or observation space, and with a plurality of records also able to calculate the direction of movement and speed of the target objects. An example of a particular use of interest of the invention is the detection of the proximity of writing and indicating tools used in relation to data projectors. Such a system, which employs camera-vision systems such as a sensor and a data projector as a source of illumination, is described in Norwegian Patent 311740 and PCT PCT / NOOl / 00369, whose patent has been extended to the United States and Europe . These patents describe a system for indication, drawing and writing on the image of the data projector and the description of possible designs / principles of the drawing, writing and indicating tool and its properties, wherein said tool is provided with a tip that It has a visual pattern with good patterns of theoretical codes for a good determination of the position in a plane of the image of the projector. These patents also cover various forms of activation principles such as the detection of proximity in direct mechanical contact with the writing surface. These patents do not cover the principles of proximity detection as described herein. As mentioned, the novel principle for proximity detection can also be used alone or combined with several principles for the determination of the position and lateral or space-related orientation of this drawing, writing and indicating tool. A combination of the invention with the positioning and orientation arrangement of the Norwegian patent 311740 and PCT patent PCT / NOOl / 00369, as explained in the preceding paragraphs, is generally used where it is desired to detect the position of one or more objects objective and also to determine the proximity to reference objects and / or determine the condition of the objects. In particular, this combination of the disclosed proximity detector with one or both of the above patents can form the basis for an indicating, drawing and writing tool having a particular robust detection and a very high profit potential. Furthermore, this combination in general can provide a robust proximity detection as well as the registration of the position and orientation of a number of marked objects in an area. The invention can also be used as a proximity detector in that drawing, writing and indicating tool even when the principles for the determination of the position and / or also the determination of the orientation in the image plane of the projector are not used. compliance with the two previous patents. The invention can also be used as an independent method or combined with one or more other methods of position determination.

One of several preferred embodiments may be as shown in Figure 2, but where the light source is a data projector and the light detector is a camera with digital detection electronics that is located adjacent to the data projector and with its axis as close as possible to the axis of the data projector. In a preferred embodiment, the camera with its digital detection electronics is incorporated in the data projector. The system of Figure 2 will be able to detect whether the interaction means such as for example a drawing, writing or indicating tool is spaced from or is closely adjacent to the writing surface (eg, a wall, a table, a board, a rear projection screen). The system in Figure 2 can also detect if buttons or other settings of the drawing tool have been pressed or if they have been activated in another way, by detecting the distance / proximity between the related objective objects and reference objects. Also the proximity detection as described above, but where the light source is not necessarily a data projector, but a source of independent constant light, pulsed or modulated with visible or invisible light, can complement such systems in order to make this more robust and redundant. The proximity detection in the case of the rear projection, wherein the projector and a camera and possibly an auxiliary light source as described above, are located behind the projection screen, and where the projection screen is of the type of diffusion, you can use for example the preferred embodiment as shown in Figure 7. The invention relates to proximity detection and position determination. Proximity detection generally has an interest in many fields of use. The optical proximity detection based on the described principle, is particularly attractive since the new technology of cameras and other optical sensors and modern lighting sources have been made available. Confocal microscopy will also have to be mentioned, where the path of the beam for illumination (typically a laser) and that goes towards the light detector passes through the same system of lenses before and after influencing the object to be studied under the microscope. . The invention makes it possible to separate the light detector and / or the light source of the objective object and the reference object. Therefore, the invention makes it possible to determine by remote detection whether the objective object and the reference object are adjacent to each other. Object object conditions can also be determined by means of such remote detection. Although several illustrative embodiments of the invention have been shown and / or described, there is of course a large number of variations and alternative modalities possible for experts in the field, while the limitations of such variations and modifications are only related to the invention as set forth in the claims. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Claims (12)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. An apparatus for detecting the proximity between a first object (objective object) and a second object (reference object), comprising a light source and a light detector adapted to receive backscattered light resulting from the reference object when illuminated from the light source, whereby the intensity of the backscattered light going to the light detector is used as a measure of that proximity, characterized because the objective object comprises an optical device having a focal plane and which is adapted to be illuminated by means of the light source, wherein the axes of the light rays of the light source and the backscatter of the light detector have portions mutually closely adjacent and substantially parallel or coincident, and where that proximity corresponds to a separation (relative position) va) between the objective object and the reference object where the reference object is located substantially in the focal plane.
2. 2. An apparatus according to claim 1, characterized in that the light source and / or the light detector are located on the target object.
3. 3. An apparatus according to claim 1 or 2, characterized in that the axes outside these portions have directions that deviate, such as through the use of mirrors, optical fibers or light conductors.
4. An apparatus according to claim 1, 2 or 3, characterized in that the light source is adapted to emit modulated or possibly pulsed light, and the light detector is synchronized with that modulation or pulsation.
5. 5. An apparatus according to any of claims 1 to 4, characterized in that the light detector comprises a camera.
6. An apparatus according to any of claims 1 to 5, characterized in that the optical device has at least two focal planes for the determination of that proximity in at least two relative positions of the objective object and the reference object.
7. 7. An apparatus according to any of claims 1 to 6, characterized in that the intensity of the retrosdispersed light going to the light detector is compared with a predetermined and preferably adjustable level, for the detection of that proximity, 8.
8. A Apparatus according to any of claims 1 to 7, characterized in that the light source and the light detector are located separately in relation to one another. .
9. An apparatus according to any of claims 1 to 8, characterized in that the light source consists of a data projector.
10. 10. A tool for drawing, writing and / or indicating for the presentation of data, computer-supported work or interactive operations with a computer, characterized in that an apparatus according to any of claims 1 to 9 is incorporated in the tool.
11. An apparatus for detecting the proximity between a first object (objective object) and a second object (reference object), comprising a light source and a receiver for the backscattered light resulting from the reference object when illuminated from the source of light, whereby the intensity of the backscattered light going towards the receiver is used as a measure of that proximity, characterized in that the objective object comprises an optical device having a focal plane and which is adapted to be illuminated by means of the source of light, where the axes of the light rays of the light source and the backscatter that goes to the receiver have mutually close portions adjacently and substantially parallel or coincident, wherein that proximity corresponds to a distance (relative position) between the objective object and the reference object where the reference object is located substantially in the focal plane, and because the receiver is adapted to cooperate with an eye belonging to a user of the apparatus.
12. 12. An apparatus according to claim 11, characterized in that the light source consists of a data projector.