Abstract:
A device for measuring physical characteristics includes a beam generator selectively generating a target beam. The device further includes two angle detectors that measure the respective angles between the beams and, respectively a vertical and a horizontal axis. The device further includes a calculator that calculates the distances to said points as well as the distance between the two points.

Description:
RELATED APPLICATIONS 
     This application is related to application Ser. No. 11/021,776 filed Dec. 23, 2004 entitled Method and Apparatus for Distance Measurement, incorporated herein by reference, now U.S. Pat. No. 7,086,162. 
     BACKGROUND OF THE INVENTION 
     a. Field of Invention 
     This application pertains to an automatic apparatus and method for measuring various dimensions such as the distance between two points. More specifically, the distance is obtained from a remote location by measuring the distances from the remote location to each of the points, measuring other parameters to determine the distance therebetween, wherein preferably a single laser device is used to make all the measurements. Other dimensions characteristic of objects such areas, volumes and/or relative positions of different objects are obtained by using three or more points. 
     b. Description of the Prior Art 
     It is frequently important to measure the distance between two points. For example, surveyors have a large number of tools and devices and disposal to measure the distances between landmarks, as well as their elevation and relative bearing. 
     Contractors and other professionals in the building industry often need to measure distances between various critical points as well. Traditionally this was accomplished by extending or laying down a measuring tape between the two points and reading the distance from the tape. If the tape was too short, or if there are obstacles between the points, then intermediate measurements are made along the path between the two points. Of course, this process is tedious and time-consuming. Moreover, in some instances, one or both points of interest are inaccessible and therefore the distance between them can be determined using indirect means or approximations. 
     Recently, the task of measuring devices has been eased somewhat by the availability of electronic measurement devices. These devices are now readily available and work by sending out an ultrasound, laser or other types of beams and determining the transit time required for the beam to reach the selected point, and return. One such device, called the Laser Dimension Master is made by Calculated Industries of Carson City, Nev. The device has a head rotatable between two perpendicular positions and generates an ultrasound beam for making measurements and a visible laser beam for aiming the device. While these devices are easy to use, most of them can still only measure the distance from the measuring device and a remote point and cannot be used from a remote location to measure the distance between two arbitrary points. One exception presently known are the laser measuring device made by Lasermeters of Edmond, Okla. (See Lasermeters.com). This company makes a line of devices under the name of Disto. A Disto device can be used to measure the distance between two points using three measurements. First, the device is directed at the first point and a measurement is taken. Next, the device is directed at an intermediate point disposed along a perpendicular line to the line between the two points and a second measurement is taken Finally, the device is directed at the second point and a third measurement is taken. The distances between the first point, the intermediate point, and the second point are determined using the Pythagorean theorem, and then added. This approach has many problems which render it impractical for most applications. First, the user must determine by eye the location of the intermediate point. Obviously this process introduces a degree of uncertainty and inaccuracy. Second, in most instances, except in very special instances, the intermediate point does not even fall between the two points, in which case, the distances must be subtracted, not added. Devices are also known that measure electronically the orientation of an object with respect to the North Pole. These devices or electronic compasses are used in various transportation means for navigation, in surveying devices, and so on. Moreover, historically, devices were well known, such as water bubbles and plumb lines that could be used to determine whether a flat member or surface was truly vertical or horizontal or to indicate the angle between a surface and a vertical or horizontal axis. More recently, devices have become available that measure such angles electronically and provide a digital signal indicative of the angle of a selected surface or line and either the vertical or horizontal axis. One such device is the Macklanburg-Duncan Electronic Digital Protractor available from Sears, Inc. of Chicago-part NO. #00940195000. 
     SUMMARY OF THE INVENTION 
     Briefly, a device for measuring the distance between two arbitrary points according to this invention includes means for determining the lengths A, B of two reference lines between a reference point and the arbitrary points includes means for determining the vertical angles VA, VB of each line with respect to a vertical axis, means for determining the bearing or orientation angles OA, OB of each line with respect to a horizontal axis, and means for calculating the distance between the points from said lengths A, B and said angles VA, VB, OA, OB. The determination is made using standard geometric formulas. Preferably the angles VA, VB, OA, OB are determined using electronic angle detectors. The distances A and B are determined by generating a measuring beam from the device to points P 1  and P 2 . The beam may be generated by a laser and may include a visible light, a UV or IR beam of light, an ultrasonic beam, etc. If the beam is not visible, an aiming beam may also be generated that is either very close to the measuring beam, or is coincident therewith. The measuring beam(and the aiming beam, if any) fall on points P 1  and P 2  and a sensor is used to detect a corresponding reflected beam. Standard techniques are used to compare the measuring beam and the reflected beam characteristics and to derive therefrom the distance to the respective point. If necessary, a reflector is placed at the points to which measurements are desired. The reflector insures that the reflected beam is strong enough so that it is detected by the sensor means. 
     In one embodiment, the device is operated as follows. The user points the device so that the measuring beam (and the aiming beam, if any) impinges or falls on a selected first point. The automatic elements of the device then measure the distance A to the first point, as well as the geographic orientation OA and the vertical angle of the beam VA with respect to a vertical axis. The device is aimed at the second point and the same parameters are obtained for this point. The parameters are used to measure the distance between the two points. By using the same parameters, and/or by targeting other points, other characteristics of an object, such as a building may be obtained as well. For example the device can be used to measure, height, width, vertical and horizontal orientation, area of one or more surfaces, the volume of various enclosures, and so on. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a somewhat diagrammatic view of how a device constructed in accordance with this invention is used to measure the distance between two arbitrary points; 
         FIG. 2  shows a somewhat diagrammatic block diagram of the device; and 
         FIG. 3  shows a plan view of the device of  FIGS. 1 and 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to  FIG. 1 , a device constructed in accordance with this invention is used to determine the distance C between two points P 1  and P 2 . The two points can be two different objects, or they can be points disposed on the same object. The distance C is determined by pointing device at reference location R at point P 1  and determining the distance A from the device to P 1 . In addition, the device also determines the vertical angle VA of line RP 1  with respect to vertical axis Z—Z as well as an orientation angle or bearing OA of line RP 1  and a horizontal reference line. Preferably the horizontal reference line is the imaginary line to the North Pole as indicated by a compass and used in navigation and surveying. Next, the device at reference R is also targeted at point P 2  and the length B of line RP 2  is determined, together with its vertical angle VB and orientation angle OB. From these parameters the distance C is determined, using standard geometrical formulas. 
       FIG. 2  shows a block diagram the device  10 . The device  10  includes a measuring or main beam generator  12  that is controlled by a push-button  14  or other similar control means. When the push-button  14  is activated, the generator  12  generates a main beam  13  that is targeted at any point P. This beam may be a visible laser beam, an ultrasound beam, an infrared beam, etc. If the beam generated by generator  12  is not visible, a secondary or aiming beam generator  16  is used to generate a secondary beam  15 . Beam  15  may be a tightly focused light beam, collimated beam, a visible laser beam etc. The purpose of beam  15  is to assist the user in the aiming of main beam  13  on point P. In one embodiment, well-known superposition means (such as mirrors  16 A,  16 B) are used to superimpose beam  15  or beam  13  so that they are coincident. Preferably mirror  16 A is fully coated to refract beam  15  as shown. Mirror  16 B is partially coated so that beam  13  passes through it and beam  15  is reflected/Instead of coating, the mirror  16 B may also be made with an aperture or clear window through which the beam  13  propagates. 
     Alternatively, the mirrors  16 A,  16 B are omitted and beams  13 ,  15 ′ are in parallel at a very close distance to each other as compared to the distance to point P. 
     At point P, the main beam  13  (or at least a portion thereof) is reflected from point P and this reflected beam  19  is directed by another partially coated mirror  16 C at a sensor  18 . The sensor  18  may be on all the time, or is activated by switch  14  as well. The sensor  18  generates an output signal indicative of the distance to the point P. 
     This signal is fed to a microprocessor  20 . In one embodiment, when push-button  14  is activated, the beam(s)  13 ,  15  are sent to the target and the sensor  18  starts generating a signal indicative of said distance. The microprocessor  20  can then calculate the distance to point P in real time in the usual manner and this distance is displayed on a display or screen  22  and stored in a memory  24 . In an alternate embodiment, the microprocessor  20  receives the data and but does not calculate the distance to point P until the push-button  14  is released. One skilled in the art understands that device may operate in many other modes as well. 
     Importantly, in the present invention, the device  10  further includes two more detectors. Detector  26  is an electronic level detector that determines from the position of device  10  the angle of beams  13 ,  15  with respect to a vertical axis. These types of detectors are well known in the art and are used frequently in surveying and construction to determine if a member is truly horizontal or vertical. Detector generates an output V indicative of this angle. 
     Detector  28  is used to determine the geographic orientations or bearings of the beams  13 ,  15 . For example, detector  28  maybe an electronic compass, such as ones made for navigation for vehicles, and other similar devices. The detector  18  generates an output O indicative of the bearing of the beams  13 ,  15 . 
     The parameters O, V are also fed to the microprocessor  20 . Again, the detectors  26 ,  28  can provide these parameters continuously or when push-button  14  is activated or released. Alternatively, other control means may be used to activate the detectors  26 ,  28  and generate respective outputs. 
     As discussed above, to make a measurement involving two points, the device is targeted at the first point, e.g., P 1 , the push-button  14  is activated and the distance A and angles VA and OA are determined. The device is then targeted at the second point P 2 , the same push-button  14 , or a different push-button is activated, and the parameters B, VB and OB are determined. Next, a relevant parameter, e.g., distance C is determined. The distance can be shown in screen  22 , optionally together with any of the parameters discussed above, In an alternate embodiment, the data is collected from sensor  18  and detectors  26 ,  28 , need not be processed immediately. These parameters are all stored in memory  24 . Signal processing and the calculation of distance C (or any other parameters can occur while the device is pointed at the second point, or even later). 
     Once the parameters A, B, VA, VB, OA, OB are determined, the distance C and many other parameters are calculated using standard geometric formulas. For example, it is well known that in the particular configuration shown in  FIG. 2  the angle S between lines RP 1  and RP 2  is related to the other angles by the formula:
 
Cos  S =cos( VA−VB )cos( OA−OB ).
 
     Then the distance C can be calculated by using the law of cosines:
 
 C   2   =A   2   +B   2 −2 AB  cos  S.  
 
     Other formulas may be used as well. 
     The range of the device  10  is dependent on a number of factors, including the reflectivity of the targeted objects at points P 1 , P 2 , the efficacy and sensitivity of sensor  18 , and so on. In some cases, a reflective surface  21  can be placed at either or both points P 1  and P 2 . The surfaces may include a metallic surface, a mirror, a polished surface, or other material that reflects the beam  13  effectively so that the reflected beam  19  has a high enough intensity to be detected by sensor  18 . 
     As mentioned above, device  10  can be used to determine not only the distance between two points but other parameters as well, using standard geometric formulas. For example, using standard geometry, device  10  can be used to measure the height of a building by measuring the distance along a vertical line between two points, one point being at the top and the other point being at the bottom. These two points can but need not be on the same vertical line. Similarly, the width of a building can be determined as well as other characteristics, such as the angle of a wall or floor with respect to vertical or horizontal axis, the orientation of a wall with respect to an axis defined by a compass, etc. The device may also be targeted at three or more lines and the resulting parameters may be used to determine various other parameters, such as area, slope, volume, etc. For example, a painter can walk into a room, point at its eight corners with device  10 , and the device  10  can automatically, calculate the total surface area of the room (with or without the ceiling) and indicate how much paint was required. 
       FIG. 3  shows a plan view of the device  10 . It includes a housing  30  with at least one screen  22  and one or more keys  32  that include the pushbutton  14  discussed above. One end, the housing has a window (not shown) through which beams  13 ,  15  are emitted and beam  19  is received. Screen  22  can be used to display all the parameters and results discussed above, either serially, or the screen can be made large enough to display either all, or a subset of the parameters and results. 
     Numerous modifications may be made to the claims without departing from its scope as defined in the appended claims.