EP1751496A1

EP1751496A1 - Instrument for measuring the height of an object

Info

Publication number: EP1751496A1
Application number: EP05701962A
Authority: EP
Inventors: Elliot Joseph Gray
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-01-27
Filing date: 2005-01-21
Publication date: 2007-02-14
Also published as: GB0401661D0; GB2410548A; WO2005071358A1; JP2007519915A; AU2005207102A1

Abstract

A measurement instrument for measuring the vertical height between two points, the device comprising: first and second rotatable measuring units (4, 6); and a processor (8) for processing data from the first and second measuring units and calculating the vertical height between the two points, wherein the first and second measuring units each comprise a rangefinder (10L, 10R) for measuring the distance from the measurement device to the first and second points respectively and an angle measurement device (16L, 16R) for calculating the angle through which the rangefinder is rotated in order to measure the vertical height.

Description

INSTRUMENT FOR MEASURING THE HEIGHT OF AN OBJECT

The present invention relates to a measurement instrument for measuring the distance between two points, for example, the total height of a load on a low loader lony from a road surface to the highest point of the load.

It is often desirable to have an accurate measurement of the height of a vehicle, particularly one which is carrying a load. Under EC regulations the total height of all commercial vehicles over 2.895m (9 feet 6 inches in UK) must be displayed in the cab of the vehicle at all times. When the load is of a regular shape, such as rectangular container, it is relatively easy to obtain a fairly accurate measurement of its height using conventional measuring sticks and the like. However, it is common for lorries to cany irregular shaped loads which are not so easily measured, for example, it is difficult to measure the total height of a low loader lorry carrying a traction engine from the top of the chimney of the traction engine to the road surface.

In these circumstances it is common for drivers to estimate the total height of the lorry and its load or to make rough measurements. This is unsatisfactory and in some circumstances can pose a considerable danger to the driver and other road users. For example, if the total height of the lorry and its load have not been accurately measured there is a real danger that the load may hit low bridges or other such obstructions.

Such hazards could be easily avoided by having a measurement instmment which could quickly and accurately provide measurements of the total height of a lorry and its load, especially when the load is of an irregular shape.

It is the object of the present invention to alleviate the problems of the prior art or at least to provide an alternative measurement instrument.

According to the present invention there is provided a measurement instmment for measuring the distance and/or angle between two points, the device comprising: first and second rotatable measuring units; and a processor for processing data from the first and second measuring units and calculating the distance between the two points,

wherein the first and second measuring units each comprises a rangefinder for measuring the distance from the measurement instrument to the first and second points respectively and an. angle measurement device for measuring the angle through which the rangefinder is rotated in order to measure the distance to the said one of the points.

It is preferred that the angle measurement device calculates the angle of rotation of the rangefinder relative to a line perpendicular to both of the points. This can be achieved by careful set up of the measuring instrument. For example, when the distance being measured is a height the instmment can be set up on a tripod and adjusted such that it is horizontal using a spirit level.

Alternatively, the instmment may be provided with means for determining the line perpendicular to the points. When the distance between the two points is a vertical height the means for determining the line perpendicular to the points may suitably comprise an artificial horizon. The artificial horizon may be integral to the instrument and provides information about the attitude of the instmment relative to the horizontal. Using this information the processor can determine the angle of each of the rangefinders above and below the horizontal.

The rangefinder may suitably be an optical rangefinder or it may be a laser rangefinder.

When the rangefinder is a laser rangefinder the laser is preferably an infra-red laser.

Each of the two rotatable measuring units is preferably provided with a camera. The cameras are preferably orientated relative to its corresponding rangefinder and are provided to record an image which includes the point at which the optical rangefinder is aimed. When the rangefinder is an optical rangefinder the camera may suitably be aligned parallel to a laser of the rangefinder or it may be offset to a calibrated distance relative to a laser of the rangefinder.

At least one of the rotatable measuring units is preferably provided with edge detection means. More preferably, both the first rotatable measuring unit and the second rotatable measuring unit are provided with edge detection means. Edge detection means enable the instmment to detect the edge of the object, for example the top edge of a vehicle when the instrument is being used to measure the height of the vehicle.

Advantageously, the instmment is provided with at least one display screen. The display screen may suitably comprise a first portion, which in use displays an image as viewed by the camera located within the first measuring unit, a second portion, which in use displays an image as viewed by the camera located within the second measuring unit and a third portion which in use displays data from the processor.

When the processor has calculated the distance between the two points it preferably produces an output comprising the measured distance and angle between the two points and the date and time at which the measurement was recorded. The output from the processor may also suitably comprise an image as produced by each of the cameras. The output may suitably be printed out by attaching the instmment to a printing device. This will provide a hard copy of the measurement data which may be displayed in the cab of- a lorry as is required by law. Alternatively, the instmment may be connected to a dock in the cab of the lorry having a graphical and/or numerical display.

Theproccssor can preferably record multiple measurements relative to afixedpoint. The instrument preferably further comprises a GPS unit connected to the processor.

According to a second aspect of the present invention there is provided a method of measuring the distance and/or angle between two points, the method comprising: using a first rangefinder to measure the distance to a first one of the points; using an associated angle measurement device to determine the angle of rotation required to move the first rangefinder from its starting position to the first one of the points; storing the data relating to the first one of the points; using a second rangefinder to measure the distance to a second one of the points; using an associated angle measurement device to detennine the angle of rotation required to move the second rangefinder from its starting position to the second one of the points; storing the data relating to the second one of the points; and transferring the data relating to the first and second points to a processor which calculates the distance between the two points.

Preferably a first rotatable measuring unit comprising a first rangefinder and a first angle measurement device measures the data relating to the first one of the points and a second rotatable measuring unit comprising a second rangefinder and a second angle measurement device measures the data relating to the second one of the points. The angle of rotation of the first and second angle measurement devices is preferably measured relative to a line peφendicular to both of the points. The rangefinder may suitably be an optical rangefinder or it may be a laser rangefinder.

For a better understanding of the present invention, reference will now be made to the accompanying drawings showing, solely by way of example, an embodiment of the present invention, in which:

Fig. 1 is a schematic diagram showing the component parts of a measuring instmment; and Fig. 2 is a side view of a measuring instmment being used to calculate the total height of a lorry and its load.

Fig. 1 is a schematic diagram showing the component parts of a measuring instmment 2. The measuring instmment 2, comprises a first measuring unit 4 and a second measuring unit 6. The first measuring unit 4 and the second measuring unit 6 are rotatably mounted on a main body (not shown). The main body contains a processor 8 and other component parts of the measuring instmment.

The first measuring unit 4 and second measuring unit 6 each comprise optical measuring equipment located within a housing (not shown). Each housing is mounted on the main body by a pivot point through its central axis, about which it is free to rotate. Alternatively, the pivot point may be offset from the centre of the housing such that when the housing is rotated about the pivot point the optical measuring equipment moves from a position where it is shielded by the main body to a position where it is exposed for use. The first measuring unit 4 and the second measuring unit 6 are each provided with a spring lo aded catch (not shown) which is received in a recess and serves to retain the respective measuring unit in a fixed position when not in use. The catch is easily overcome by the application of a rotational force by a user.

The first measuring unit 4 and second measuring unit 6 are symmetrically disposed about a central axis of the main body. The first, or left, measuring unit 4 measures the distance from the measuring instmment 2 to a first point. This may typically be the bottom of an object or the road surface on which a lorry is parked. The second, or right, measuring unit 6 measures the distance from the measuring instmment 2 to a second point. This may typically be the top of an obj ect or the highest point of a load on a lorry. The two points may be offset relative to each other. When this is the case the distance calculated is the vertical distance from the second point to the bottom of the object being measured.

The first measuring unit 4 and second measuring unit 6 each comprise the same components and will be described with reference to the first measuring unit 4. It will be understood that this description applies to the second measuring unit 6 and that the two units may in fact be interchangeable parts which maybe fitted on either side of the measuring instmment 2. The same reference numerals will be used in both the first measuring unit 4 and the second measuring unit 6. The component parts of the first measuring unit 4 will be denoted (L) and the component parts of the second measuring unit 6 will be denoted (R). Such versatility reduces manufacturing costs since it is only necessary to manufacture a single type of measuring unit.

The first measuring unit 4 comprises an optical depth of field rangefinder 10L which is aligned parallel to a laser unit 12L. hi an alternative embodiment the laser unit 12L may be slightly offset with respect the optical depth of field rangefinder 10L such that the two intersect at a certain predetermined distance. The laser unit 12L is an infrared laser and emits infrared light. In use, the infrared light from the laser unit 12 is aimed at the first point and the optical depth of field rangefinder 10 determines the distance from the measuring instmment 2 to said point. The operation of such optical depth of field rangefinders will b e easily understood by someone of average skill in the art and wil 1 not be described in detail. The optical depth of field rangefinder 10 and the laser unit 12 are connected to the processor 8. The processor 8 receives distance data from each of the measuring units and uses this data to calculate the distance between the two points as will be described below.

hi an alternative embodiment the optical depth of field rangefinders 10L, 10R may be replaced by laser rangefinders.

In addition to the optical rangefinder 10L and the laser unit 12L, the measuring unit 4 comprises a camera 14L and an angle measuring device 16L, both of which are also connected to the processor 8. The camera 14L is arranged to record an image of the fixed point at which the laser unit 12L is aimed at the moment at which the distance data is captured. The image produced by the camera 14L will show a laser spot and a portion of the target object at which the measuring unit 4 is directed. This image can be used to provide verification for the distance data as produced by the processor 8, as will be described below. The angle measuring device 16 measures the angle through which the measuring unit 4 is rotated, relative to a set point, in order to aim the laser unit 12L at the chosen point. When the measuring instmment 2 is being used to measure the height of an object the set point against which the angle measurement is taken is the horizontal. When this is the case the angle measuring device 16L measures the angle through which the first measuring unit 4 is rotated downwards, with respect to the horizontal, in order for the laser unit 12L to point at the bottom of the object. In the case of the second measuring unit 6, the angle measurement device 16R measures the angle through which the unit 6 is rotated upwards, with respect to the horizontal, in order for the laser unit 12R to point at the top of the object.

hi order to provide accurate height measurements the measuring instmment 2 is provided with an artificial horizon 18. Such devices are used in aircraft and also called gyro horizons and provide an indication of the attitude of the instmment 2 in relation to the horizontal. The artificial horizon 18 is connected to the processor 8 and in conjunction with the data provided by the angle measurement devices 16 the processor is able to calculate the depth of the first measurement unit 4 below the horizontal and the height of the second measurement unit 6 above the horizontal. The artificial horizon 18 enables the user of the measuring instrument 2 to obtain accurate measurements regardless of whether or not the instmment 2 is held horizontally. In an alternative embodiment of the invention, the instrument 2 may not be provided with an artificial horizon 18 and instead it may be mounted on a tripod or stand which will ensure it remains stable. A simple device, such as a spirit level, may be used to ensure that the instmment 2 is horizontal before the distance data is captured. A spirit level may be provided integrally within the main body.

The main body is provided with a display screen 20 which is connected to each of the cameras 14 via the processor 8. The display screen 20 comprises a first portion (not shown) on the left-hand side thereof which, in use, shows an image as viewed by the camera 14L, located within the first measurement unit 4, a second portion (not shown) on the right-hand side thereof which, in use, shows an image as viewed by the camera 14R located within the second measuring unit 6 and a third portion (not shown) which, in use, displays the data captured by the instmment and any additional information, such as date/time. The cameras 14 are digital cameras with previewing and the images recorded by the cameras are stored in memory unit 22. The memory unit 22 is a removable memory media. Alternatively, the instmment 2 may be provided with an integral memoiy unit or a combination of a removable and an integral memory unit. In addition to the display screen 20, the instmment is also provided with conventional optical viewfmders (not shown) such that a user may choose to view the object using either the display screen 20 or the optical viewfinder. These features are found on many conventional digital cameras.

The instmment 2 is powered by a built-in power source 24. The power source 24 is a rechargeable battery pack. Alternatively, the instmment may be plugged into the mains to operate or it may run off conventional batteries. The instrument is turned off and on using switch 26. A back-up power source 28 is provided to provide power for the clock which is built into the processor 8 and must maintain the corcect time and date even when the instmment 2 is switched off for extended periods. A keypad 30 is provided to facilitate the selection of features and to enable manual entry of data into the processor 8.

In addition, the instrument 2 may be provided with edge detection means (not shown). Preferably at least one of the rotatable measuring units 4, 6 is provided with edge detection means. Edge detection means is particularly useful when the instmment 2 is being used to measure the height of a loaded vehicle. Rather than the need to aim the first and second measuring units 4, 6 at top and bottom target points before aclivating the instmment for data capture, it is only necessary to aim the first measuring unit 4 at a bottom target point. The second measuring unit 6 may then be aimed above the top target point and rotated downwards until the edge detection means detects the top edge. This will then set the data capture process in motion and record the necessary data. The edge detection means is easily implemented as the second measuring unit 6 will be recording an infinite distance while the unit 6 is aimed above the top edge. As soon as the unit 6 detects the top edge the instrument 2 can be programmed to begin data capture, without the need to activate a separate button.

The instmment is also provided with a built-in GPS unit and compass 32. This component is optional and is not provided on the standard model measuring instrument

2. The standard model measuring instrument 2 is used for measuring the height of an object and will therefore have no need for position data such as will be provided by a GPS unit 32. However, other applications of the unit, as will be described below, will benefit from such data. Consequently, the GPS unit 32 is shown connected to the processor 8.

As a further modification, the instmment may be provide with a remote control device such that the instmment maybe set up and measurements recorded by a user in a remote location.

An application of the measuring instmment will now be described with reference to Fig. 2 which shows a side view of the measuring instmment 2 of Fig. 1 being used to measure the height of a flatbed lony 36 carrying an irregular shaped load 38. It would nonnally be difficult to measure the combined height (C) of such a lorry 36 and its load 38.

The measuring instrument 2 is first turned on at switch 26 and the instrument 2 is held such that the target object, in this case the lorry 36 and its load 38, are sighted on the display screen 20. The artificial horizon 18 provides the processor 8 with data regarding the attitude of the instmment 2 in relation to the horizontal.

The first measuring unit 4 is rotated downwardly until the laser spot emitted by the laser unit 12L is positioned at a first point at the bottom of the target object. Depending on the proximity of the target object this may be determined either by viewing the target object directly or by viewing it on the first portion of the display screen 20 or through the optical viewfinder. Next, the second measuring unit 6 is rotated upwardly until the laser spot emitted by the laser unit 12R is positioned at a second point at the top of the target object. Again, this maybe determined by viewing the target object directly or by viewing it on the second portion of the display screen 20 or through the optical viewfmder.

When both laser spots are satisfactorily positioned the user may activate the measuring instmment by pressing the shutter button 34. This sets the data capture process in motion. The optical depth of field rangefinders 10L, 10R send data to the processor regarding the distances (Dl) and (D2) from the instmment 2 to each of the points. The processor 8 takes a reading from the artificial horizon 18 and each of the angle measuring devices 16L, 16R and determines the angle (a) below the horizontal of the first measuring unit 4 and the angle (b) above the horizontal of the second measuring unit 6.

In addition, upon the activation of shutter button 34, the cameras 14L, 14R in each of the measuring units 4,6 record still pictures of the points showing the position of the laser spots emitted by the laser units 12L, 12R. Any additional data which is required by the processor, such as data from the GPS unit 32 is also captured.

hi the alternative embodiment, when the instrument is provided with edge detection means, there is no need for a separate shutter button 34. The instmment 2 can be set up such that data capture begins when the second measuring unit 6 detects the top edge of the target object.

The processor 8 then performs a simple calculation to calculate the total height (C) of the target object as shown below with reference to Fig. 2. The total height (C) is not necessarily the distance between the two points but rather it is the distance of the second point above the ground. Sample calculation

The calculation is performed in two parts. Firstly, the depth (A) of the first point below the artificial horizon is calculated using the distance (Dl) between the instmment and the point and the angle (a) below the horizontal.

Next, the height (B) of the second fixed point above the artificial horizon is calculated using the distance (D2) between the instmment and the second fixed point and the angle above the horizontal.

The total height is then calculated by adding the two figures together.

Depth A = sin a x distance (D 1 ) = sin 42° x 2320 = 1552.312mm

Height B = sin b x distance (D2) = sin 62° x 3600 = 3178.44mm

Total height (C)of target object = 1552.312 + 3178.44 = 4730.752mm

The example shown uses simple trigonometry to calculate the total height (C) of the target object. It will be understood that the processor 8 will be capable of perfonxiing other calculations based on the data received from the optical depth of field rangefinders 10L, 10R, the angle measuring devices 16L, 16R, and, optionally, the artificial horizon 18 and the GPS unit 32.

As mentioned above, the instrument can provide a permanent record of the measured height of the lorry and its load. This is particularly useful since under EC regulations the total height must be displayed in the cab of the lorry. The processor 8 combines the images provided by the cameras 14 and the calculation performed using the captured data and produces an output showing the information and the time at which it was recorded. The output from the processor 8 can be printed such that a hard copy can be displayed in the cab of the lony. This is particularly useful since the images show the laser spots at the top and bottom of the target object and thus can be used to verify that the height measurement applies to the particular load. In addition, the date and time, as supplied by the internal clock in the processor 8, can be added to the print out to verify that the measurement was recently recorded.

Alternatively, the instmment 2 may be provided with a dock which may suitably be located within the cab of the lorry and into which the instmment may be connected when the height measurement has been recorded. The dock may suitably be provided with a display, capable of displaying graphical data and/or numerical data. It is envisaged that a user would use the instrument 2 to record the total height of the vehicle and its load and then connect the instmment 2 to the dock, which provides a housing for the instmment 2 when not in use, and which will display the data output from the processor 8.

The above example shows how the instmment can be used to determine the height of an object such as a lorry and its load. However, the instmment 2 can be used to perfonn a number of different measuring functions.

The instmment can be used to measure horizontal distances and angles as well as vertical distances and it can be used to take more than two measurements, for example, for calculating the volume of any internal space, such as a cave or a cathedral.

An alternative use of the instalment would be at the scene of a road traffic accident where there is the need for measuring multiple angles from a convenient safe position. This would be accomplished by mounting the instrument horizontally on a tripod with a clear view of the scene. The instmment would be aligned with a central point in the accident and used to take pictures of prominent points. This would allow a more complete view of the accident scene to be established, which will improve the context. Additional infonnation from the GPS unit 32 may also be utilised in this application. The data obtained using the instmment 2 is compatible with CAD programs such as AutoCAD, which allows the 3D mapping of the measurements.

Claims

1. A measurement instmment for measuring the distance and/or angle between two points, the device comprising: first and second rotatable measuring units; and a processor for processing data from the first and second measuring units and calculating the distance between the two points,

wherein the first and second measuring units each comprises a rangefinder for measuring the distance from the measurement instrument to the first and second points respectively and an angle measurement device for measuring the angle through which the rangefinder is rotated in order to measure the distance to the said one of the points.

2. A measurement instmment according to claim 1, wherein the angle measurement device calculates the angle of rotation of the rangefinder relative to a line perpendicular to both of the points.

3. A measurement instmment according to claim 2, wherein the instmment is provided with means for determining the line perpendicular to the points.

4. A measurement instmment according to claim 3, wherein the distance between the two points is a vertical height and the means for determining the set point comprises an artificial horizon.

5. A measurement instmment according to any preceding claim, wherein the rangefinder is an optical rangefinder.

6. A measurement device according to any one of claims 1-4, wherein the rangefinder is a laser rangefinder.

7. A measurement instmment according to claim 9, wherein the laser is an infrared laser.

8. A measurement instmment according to any preceding claim, wherein each measuring unit is provided with a camera.

9. A measurement instmment according to claim 8, wherein each camera is orientated relative to a corresponding one of the rangefinders and records an image of the point at which the optical rangefinder is aimed.

10. A measurement instrument according to claim 9, as dependent on claim 5, wherein each camera is aligned parallel to a laser of its respective rangefinder.

11. A measurement instmment according to claim 9, as dependent on claim 5, wherein each camera is aligned offset to a calibrated distance relative to a laser of its respective rangefinder.

12. A measurement instmment according to any preceding claim, wherein at least one of the rotatable measuring units is provided with edge detection means.

13. A measurement instmment according to claim 12, wherein the first rotatable measuring unit and the second rotatable measuring unit are both provided with edge detection means.

14. A measurement instmment accordingto any one of claims 8-13, wherein the instmment is provided with at least one display screen.

15. A measurement instmment according to claim 14, wherein the display screen comprises a first portion, which in use displays an image as viewed by the camera located within the first measuring unit, a second portion, which in use displays an image as viewed by the camera located within the second measuring unit and a third portion which in use displays data from the processor.

16. A measurement instmment according to any preceding claim, wherein the processor produces an output comprising the measured distance and angles between the two points and the date and time at which the measurement was recorded.

17. A measurement instmment according to claim 16, as dependent on any one of claims 8-11, wherein the output comprises an image as produced by each camera.

18. A measurement instmment according to any preceding claim, wherein the processor can take multiple measurements relative to a fixed reference point.

19. A measurement instrument according to any preceding claim, wherein the instmment further comprises a GPS unit.

20. A method of measuring the distance and/or angle between two points, the method comprising: using a first rangefinder to measure the distance to a first one of the points; using an associated angle measurement device to determine the angle of rotation required to move the first rangefinder from its starting position to the first one of the fixed points; storing the data relating to the first one of the fixed points; using a second rangefinder to measure the distance to a second one of the fixed points; using an associated angle measurement device to determine the angle of rotation required to move the second rangefinder from its starting position to the second one of the fixed points; storing the data relating to the second one of the fixed points; and transferring the data relating to the first and second fixed points to a processor and calculating the distance between the two fixed points.

21. A method according to claim 20, wherein a first rotatable measuring unit comprising a first rangefinder and a first angle measurement device measures the data relating to the first one of the points and a second rotatable measuring unit comprising a second rangefinder and a second angle measurement device measures the data relating to the second one of the points.

22. A method according to claim 20 or claim 21, wherein the angle of rotation of the first and second angle measurement devices is measured relative to a line perpendicular to both of the points.

23. A method according to any one of claims 20-22, wherein the rangefinder i s an optical rangefinder.

24. A method according to any one of claims 20-22, wherein the rangefinder is a laser rangefinder.

25. A measurement instmment substantially as hereinbefore described with reference to the accompanying drawings.

26. A method substantially as hereinbefore described with reference to the accompanying drawings.