System and method for measuring conveyor-belt elongation

Abstract

A measurement system and a method for measuring conveyor belts. The measurement system includes a camera, a display screen, and a memory, which may be housed in a handheld device, such as a smartphone. The camera takes photos of a target surface of a belt. The photos are processed and compared to a reference pattern stored in a database in memory. From the comparison the longitudinal elongation of the belt is determined. The percent elongation from nominal longitudinal belt pitch is displayed so that the belt can be replaced if necessary. The software program can also process the image frames taken by the camera and display graphical indicators guiding the user's positioning of the camera into an effective position and orientation for accurate measurements.

Description

[0001] SYSTEM AND METHOD FOR MEASURING CONVEYOR-BELT ELONGATION

[0002] BACKGROUND

[0003] The invention relates generally to a system and a method for measuring the elongation of conveyor belts and, more particularly, to a system and a method using a camera to measure belt elongation.

[0004] Modular plastic conveyor belts are widely used to convey items in industrial plants. The belts are constructed of rigid plastic belt modules arranged in rows of one or more of the modules joined end to end by hinge rods extended through the aligned apertures of interleaved hinge elements at hinge joints between adjacent rows. The distance between consecutive hinge joints is the longitudinal pitch of the belt. A new belt has a specified nominal longitudinal pitch. But as the belt is used, it tends to stretch, or elongate. The elongation, which increases the belt's longitudinal pitch, is due to thinning or cam-shafting of the hinge rods or to wallowing out of the walls bounding the hinge elements' apertures. When belt elongation increases enough beyond its nominal value, engagement with the conveyor's drive and idle sprockets can suffer. In particular, the belt can intermittently ride up on the sprocket teeth and fall out of engagement, which can reduce the belt's loadcarrying capacity and can cause belt-speed fluctuations and jostling of conveyed items. Belt elongation of as little as 3% of the belt's nominal longitudinal pitch can cause intermittent belt-sprocket disengagement.

[0005] Visioning systems are often used to measure items. In a typical setup for measuring, a camera is fixed at a known distance from and a known orientation to the target to be measured. In that case, a permanent calibration, necessary for accurate measurements, can be used. But overcoming the calibration problem by setting up a fixed vision system is expensive and time-consuming.

[0006] SUMMARY

[0007] One version of a belt measuring system comprises a camera, a display screen, and a memory in which a reference pattern of a repeated belt feature on a target surface of a conveyor belt is stored. A software program is stored in memory. When selected to run by a user, the program executes program instructions in memory to: (a) grab target image frames of the target surface as produced by the camera when the camera is aimed at the target surface by the user; (b) perform correlations of the reference pattern to the target image frames to identify locations of the repeated belt feature in the target image frames; (c) determine the camera position relative to the target surface from the correlations; (d) display on the display screen graphical indicators to guide the user in positioning the camera into an effective position relative to the target surface so that accurate measurements of the repeated belt feature can be made; and (e) measure the distance between the repeated belt features on the target surface from the correlations as a measurement value when the camera is in an effective position relative to the target surface.

[0008] Another version of a belt measuring system comprises a handheld device including a camera, a display screen, and a memory in which a belt database including a plurality of reference patterns of repeated belt features on target surfaces of a plurality of conveyor belts of different belt styles is stored. A software program is stored in memory. When selected to run by a user, the software program executes program instructions in memory to: (a) grab target image frames produced by the camera of the target surface of a conveyor belt to be identified when the camera is aimed at the target surface by the user; (b) perform correlations of the plurality of reference patterns to the repeated belt features in the target image frames to identify the belt style with the greatest correlation; and (c) display on the display screen the belt style with the greatest correlation.

[0009] A method for measuring a conveyor belt comprises: (a) running a software program in a belt measuring system that includes a camera, a display screen, and a belt database stored in memory in which a belt database is stored; (b) aiming the camera at a target surface on a conveyor belt to take target image frames of the target surface. The software program executes program instructions in memory to: (i) grab target image frames of the target surface as produced by the camera; (ii) perform correlations of a reference pattern of a repeated belt feature on a target surface of the conveyor belt in the belt database to the target image frames to identify locations of the repeated belt feature in the target image frames;

[0010] (iii) determine the camera position relative to the target surface from the correlations;

[0011] (iv) display on the display screen graphical indicators to guide the user in positioning the camera into an effective position relative to the target surface so that accurate measurements of the repeated belt feature can be made; and (v) measure the distance between the repeated belt features on the target surface from the correlations as a measurement value when the camera is in an effective position relative to the target surface.

[0012] BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is an isometric view of one version of a measuring system for a conveyor belt.

[0014] FIG. 2 is a schematic drawing of a handheld device usable in the measuring system of FIG. 1.

[0015] FIG. 3 is a target image frame of a portion of a conveyor belt taken by a measuring system as in FIG. 1.

[0016] FIG. 4 is a representative of a reference pattern, or marker, for a conveyor belt as in FIG. 1.

[0017] FIG. 5 is a target image frame of a conveyor belt as in FIG. 1 taken from a viewpoint not perpendicular to the belt's target surface.

[0018] FIG. 6 is a target image frame of a conveyor belt as in FIG. 1 taken from a viewpoint perpendicular to the belt's target surface.

[0019] FIG. 7 is a flowchart describing the operation of the measuring system of FIG. 1.

[0020] FIGS. 8A-8H depict one version of graphical indicators displayed to guide a user to properly position and orient the camera for an accurate measurement.

[0021] FIGS. 9A-9H depicts a second version of graphical indicators to guide the user's positioning of the camera.

[0022] FIGS. 10A-10H are a third version of graphical indicators to guide the user's positioning of the camera.

[0023] FIG. 11 shows the display of a good measurement using the graphical indicators of FIG. 10A.

[0024] DETAILED DESCRIPTION

[0025] A conveyor-belt measuring system is shown in FIG. 1. The belt measuring system comprises a handheld device 20 making measurements of a conveyor belt 22. The handheld device 20, such as a smartphone 24 as in FIG. 2, houses a camera 26 (on the flip side), a display screen 28, and memory 30 (internal) that includes a program memory section and a data memory section. The camera 26 of the handheld device 20 is aimed by a user at a target surface 32, such as the conveying surface, of the conveyor belt 22. A software program, such as a smartphone app, executing program steps stored in the program memory section of memory 30 grabs target image frames 34 of a portion of the target surface 32 taken by the camera 26. Preferably, the camera 26 is held in a perfect position: (a) with its lens parallel to the target surface 32; i.e., aimed perpendicular to the target surface; (b) with the camera oriented so that the target image frame is squared with the longitudinal and transverse axes of the target surface; and (c) at a distance from the target surface sufficient for the target image frame to include enough repeated belt features on the target surface for accurate measurements to be made. But holding the camera 26 precisely in the perfect position is almost impossible. Thus, it is necessary only that the camera be held in an effective position (distance from and orientation relative to the target surface) that allows the software program to locate the repeated belt features in the target image frame and transform the target image frame by translation and rotation about three axes as necessary to simulate a target image taken from a perfect position so that accurate measurements can be made.

[0026] Initially, a target image frame 36 as in FIG. 3, in which the belt is skewed relative to the frame, is taken. As the camera 26 continues to take photos, the software program processes the photos and guides the user via the display screen 28 with graphical indicators to orient and position the camera so that it reaches an effective position close enough to the perfect position for accurate measurements of the belt 22 to be made from the target image frames. Once the camera 26 is in an effective position relative to the target surface 32, the user holds the camera stationary for a few seconds while the measurement is made. The results of the measurement are then displayed in the display screen 28.

[0027] Stored in the data memory section of memory 30 is a belt database that contains a reference pattern 38 of a repeated belt feature. In the example of FIG. 4, the reference pattern 38 is a region on the belt's target surface 32 that includes a portion of the belt's hinge joint as would be seen in a plan view. In this case, the reference pattern 38 is a segment of the hinge joint that is twice the transverse pitch of the belt's hinge elements 39. The database may include more than one reference pattern representing other belt styles. If the database does include reference patterns of different belt styles, the user selects the target belt style so that the corresponding reference pattern is used.

[0028] The belt database may also include pattern data corresponding to each reference pattern. The pattern data may include the nominal longitudinal pitches PL and the nominal transverse pitches PT of the reference pattern of the repeated belt features, as shown in FIG. 1. The pattern data may also or instead include the ratio RTL of the nominal transverse pitch PT to the nominal longitudinal pitch PL, or its reciprocal RLT.

[0029] Additionally, the belt database can include for each reference pattern individual vision-processing settings, such as high- and low-pass filter settings, image normalization settings, contrast settings, and brightness settings, for customizing the processing of the target image frame. Other settings tailored to each reference pattern can include minimum and maximum camera distances from the belt, or zoom limits, and limits on camera rotation and skewing, for example. For a belt database containing multiple reference patterns, an individual belt-style identifier is stored in the database for each reference pattern.

[0030] The handheld device's camera 26 takes photos continuously; e.g., at a rate of 5 to 30 frames per second. That allows the software program to continuously update the display screen 28 with the graphical indicators to guide the user's positioning of the camera 26 to an effective position for an accurate measurement. Although single-shot measurements are possible, using a single shot relies on the user's positioning of the camera 26 in an effective position relative to the target surface 32 of the belt 22. The final measurement, taken when the camera 26 is in an effective position, takes only about five seconds to process. And the measurement can be taken whether the belt 22 is stationary or moving.

[0031] A flowchart indicating the steps of the measurement process is shown in FIG. 7. The first step is to select the style of conveyor belt to be measured so that the software program can retrieve the appropriate reference pattern from memory. If the database contains only one reference pattern, this step is unnecessary. The user aims the camera at the target surface of the belt, a photo is taken, and the software program grabs the belt target image frame. The software program locates the repeated belt features 40, or markers, in the target image frame 42, as shown in FIG. 5, by correlating the reference pattern 38 (FIG. 4) with the target image frame. Because the early photos may not be taken by the camera in an effective position but will be oriented and distanced improperly for accurate measurements, the image frame is characterized as a three-dimensional (3D) image and the markers 40 as 3D markers.

[0032] The target image frame 42 of FIG. 5 represents a 3D image taken by the camera from an angle tilted off the perpendicular to the target surface of the conveyor belt. That's indicated by the convergence of the dotted lines 44 through the 3D markers 40 along each hinge joint of the frame 42 away from the camera's position along the Y axis 46. The X axis 47 is orthogonal to the Y axis 46 in the plane of the image. And the Z axis 48 is orthogonal to the Y and X axes 46, 47. By analyzing the dotted lines 44 through the markers 40 along the hinge joints and dashed lines 45 through the markers from hinge joint to hinge joint, the software program determines the camera's position and orientation relative to the belt's target surface. In the example target image frame 42 of FIG. 5, the camera's orientation is tilted only about the X axis. That's because the dashed lines 45 are parallel to the X axis and the dotted lines 44 converge away from the camera's position along the Y axis 46. With this information the software program can transform the perspective 3D target image frame 42 into a two-dimensional (2D) plan- view image frame 50 as in FIG. 6 from which accurate measurements might be made. Alternatively or additionally, the information can be used to display graphical indicators that guide the user to properly position the camera into an effective position. The information gleaned by analyzing the markers 40 in the target image frame 42 of FIG. 5 suggests that the camera be rotated Rx about the X axis 47 to improve the view. Rotations RY, RZ about the Y and Z axes 46, 48 are unnecessary in this example. Likewise, translations Tx, TY of the camera along the X and Y axes 47, 46 to minimize the capture of off-belt regions in the target image frame are not necessary in this example.

[0033] After the locations of the 3D markers 40 and the camera's position and orientation have been determined, the software program can display camera-positioning feedback in the form of graphical indicators that help guide the user to position and orient the camera into effective positions for accurate measurements. Examples of three versions of graphical indicators are shown in FIGS. 8A-8H, 9A-9H, and 10A-10H.

[0034] The graphical indicators in FIGS. 8A-8H displayed in the display screen include a pair of similar concentric stationary rectangles (or squares) 52, 54 and a movable tetragon 56 whose orientation, size, and shape change as the camera's orientation relative to and distance from the belt's target surface changes. The target surface is framed relative to the camera for accurate measurements when the tetragon 56 is concentric or nearly concentric enough with and lies largely between the two stationary rectangles 52, 54, as in FIG. 8A. FIGS. 8B-8H depict other camera-to-target-surface situations. FIG. 8B guides the user to translate the camera along the X axis. FIG. 8C guides the user to translate the camera along the Y axis. FIG. 8D guides the user to translate the camera away from the target surface along the Z axis. FIG. 8E guides the user to rotate the camera about the Z axis. FIG. 8F guides the user to rotate the camera about the Y axis. FIG. 8G guides the user to rotate the camera about the X axis. FIG. 8H guides the user to translate the camera along the Z axis closer to the target surface. To further aid the user's positioning of the camera in an effective position, the tetragon 54 can be dotted as shown in the drawing or can be a different color than that of the rectangles 52, 54. For example, the tetragon 56 can be red and the rectangles 52, 54 black. And the red tetragon's color can be changed from red to green, for example, when the camera is in an effective position to make accurate measurements, as in FIG. 8A.

[0035] FIGS. 9A-9H show an alternative version of graphical indicators in the form of a stationary cross 60 fixed in size and a guide cross 62 whose orientation and size change as the camera's orientation relative to and distance from the belt's target surface changes. The situations indicated by FIGS. 9A-9H are identical figure by figure to those depicted in FIGS. 8A-8H. When the camera is positioned in an effective position for accurate measurements, the movable guide cross 62 is coincident or close enough to coincident in extent and position with the stationary cross as in FIG. 9A. And like the graphical indicators of FIGS. 8A-8H, colors can be used as aids. For example, the stationary cross can be black, and the guide cross can be red until it turns green when the camera is properly positioned as in FIG. 9A.

[0036] An example of a third alternative set of graphical indicators is shown in FIGS. 10A- 10H. They also represent figure by figure the corresponding situations of FIGS. 8A-8H and FIGS. 9A-9H. This set of graphical indicators uses stationary and guide crosses 70, 72 similar to those in FIGS. 9A-9H. A stationary solid-filled circle 74 is concentric with the stationary cross 70. The movable guide cross 72 is concentric with a guide ellipse 76 whose orientation, size, and eccentricity change as the camera's orientation relative to and distance from the belt's target surface changes. The eccentricity increases from 0 for a circular ellipse, or circle, to 1 for a flattened degenerate ellipse. The eccentricity of the guide ellipse 76 is proportional to the tilt of the camera off the Z axis, as represented by the graphical indicators of FIGS. 10F and 10G. When the camera is too far from the belt's target area, the guide ellipse 76 lies within the stationary circle 74 as in FIG. 10D. If the camera is too close, the stationary circle 74 lies within the guide circle 76 as in FIG. 10H. And colors may be used to aid the user's positioning of the camera. For example, the stationary circle 74 can be solid black, the stationary cross 70 can be outlined in black, and the guide ellipse 76 can be red with a white interior. The guide cross 72 can be red. And when the camera is positioned in an effective position for an accurate measurement, the guide ellipse 76 is circular or nearly circular enough and lies within the boundaries of the stationary circle 74, and its color changes to green, along with the guide cross 72, which then coincides with the stationary cross 70.

[0037] The software program, as shown in FIG. 7, then transforms the 3D target image frame 42 of FIG. 5 into a transformed 2D target image frame, in which the transformed target image frame 50 is parallel to the target surface so that the belt markers 40 are aligned in orthogonal rows and columns parallel to the X and Y axes 47, 46 as shown in FIG. 6. The X-axis and Y-axis coordinates in the camera's pixel units of the marker locations in the transformed target image frame 50 are determined. From those coordinates, the software program calculates the percent belt longitudinal elongation E along the X axis 47 as

[0038] E = [RTL» (PLM / PTM) - l] »100%, where PLM is the longitudinal (X-axis) pitch of the markers 40 measured in the transformed target image frame 50, PTM is the transverse (Y-axis) pitch of the markers in the transformed target image frame, and RTL is the ratio of the nominal transverse pitch to the nominal longitudinal pitch.

[0039] Because the camera is handheld, the measurements are subject to measurement noise. The software program can reduce measurement noise by basing the final measurement value on an average of a series of individual measurements. Furthermore, a measurement error is calculated and displayed to provide the user with a quantitative measure of the reliability of the measurement of belt elongation. The measurement error is calculated by the software program as plus or minus a predetermined multiple of the standard deviation cr of the most recent valid measurement values. For example, a measurement error of ±3cr could be used. The number of valid measurement values used to compute the standard deviation is a value stored in settings in the database.

[0040] The results of the calculations are displayed in the display screen as in FIG. 11 using the graphical indicators of FIG. 10A in this example. The display screen presents the graphical indicator 80, the belt style 82, the percent longitudinal elongation E of the conveyor belt, and the measurement error 84. If the standard deviation or the measurement error is greater than a predetermined fraction of the measurement values, the measurement error 84 or the percent longitudinal elongation E or both can be displayed in red or flashing to indicate a questionable percent elongation value. If the standard deviation or the measurement error is less than a predetermined fraction of the measurement values, the measurement error 84 or the percent longitudinal elongation E or both can be displayed in green to indicate a valid percent elongation value. The graphical indicator 80 also indicates the measurement error qualitatively by the deviation of the guide cross 72 from the stationary cross 70. From the displayed values of percent longitudinal belt elongation E and measurement error 84, the user can decide whether the conveyor belt should be replaced.

[0041] Although the belt measuring system has been described in detail with respect to an exemplary version, other versions and uses are possible. For example, the belt measuring system can be used to identify a belt's style by correlating its target image frame to the library of reference image frames stored in memory and selecting and displaying the belt style of the reference image frame with the highest correlation value above an acceptable predetermined threshold. Using similar measurement and correlation techniques, the software program can also detect broken or damaged belt modules or degraded target surfaces and alert the user by displaying a message in the display screen. And, of course, colors and display effects other than those mentioned can be displayed to guide the user into positioning the camera in an effective position for accurate measurements to be made. Although all the exemplary versions describe a handheld device, especially a smartphone, the system and method can also be used to set up a fixtured camera measurement system to measure belt elongation.

Claims

What is claimed is:

1. A belt measuring system comprising: a camera; a display screen; a memory in which a belt database including a reference pattern of a repeated belt feature on a target surface of a conveyor belt is stored; a software program stored in memory that, when selected to run by a user, executes program instructions in memory to: grab target image frames of the target surface as produced by the camera when the camera is aimed at the target surface by the user; perform correlations of the reference pattern to the target image frames to identify locations of the repeated belt feature in the target image frames; determine the camera position relative to the target surface from the correlations; display on the display screen graphical indicators to guide the user in positioning the camera into an effective position relative to the target surface so that accurate measurements of the repeated belt feature can be made; measure the distance between the repeated belt features on the target surface from the correlations as a measurement value when the camera is in an effective position relative to the target surface.

2. The belt measuring system as claimed in claim 1 wherein the belt database includes the nominal longitudinal and transverse pitches or the ratio of the nominal longitudinal pitch to the nominal transverse pitch, or vice versa, of the repeated belt features scaled to the reference pattern.

3. The belt measuring system as claimed in claim 1 wherein the belt database includes a plurality of reference patterns, each corresponding to a different belt style.

4. The belt measuring system as claimed in claim 3 wherein the belt database includes a belt-style identifier corresponding to each reference pattern.

5. The belt measuring system as claimed in claim 4 wherein the software program identifies the belt style of the conveyor belt by performing correlations of the target image frames to the reference patterns and displaying the belt-style identifier associated with the reference pattern whose correlation with the target image frames is greatest.

6. The belt measuring system as claimed in claim 3 wherein the belt database includes pattern data corresponding to each reference pattern, wherein the pattern data corresponding to each reference pattern includes the nominal longitudinal and transverse pitches or the ratio of the nominal longitudinal pitch to the nominal transverse pitch, or vice versa, of the repeated belt features scaled to the reference pattern.

7. The belt measuring system as claimed in claim 3 wherein the belt database includes vision-processing settings corresponding to each reference pattern for customizing the processing of the target image frames for each belt style.

8. The belt measuring system as claimed in claim 1 wherein the graphical indicators provide feedback in the display to the user by changing in appearance as the user, guided by the feedback, moves the camera into an effective position relative to the target surface for accurate measurements to be made.

9. The belt measuring system as claimed in claim 1 wherein the graphical indicators in the display screen include a tetragon whose orientation, size, and shape change as the camera's orientation relative to and distance from the target surface changes.

10. The belt measuring system as claimed in claim 9 wherein the graphical indicators include a pair of fixed concentric rectangles and wherein the camera is in an effective position relative to the target surface for accurate measurements to be made when the tetragon is concentric with and lies between the pair of fixed concentric rectangles in the display screen.

11. The belt measuring system as claimed in claim 1 wherein the graphical indicators in the display screen include a guide cross whose orientation and size change as the camera's orientation relative to and distance from the target surface changes.

12. The belt measuring system as claimed in claim 11 wherein the graphical indicators include a fixed cross and wherein the camera is in an effective position relative to the target surface for accurate measurements to be made when the guide cross coincides with the fixed cross.

13. The belt measuring system as claimed in claim 1 wherein the graphical indicators include a guide ellipse whose orientation, size, and eccentricity change as the camera's orientation relative to and distance from the target surface changes.

14. The belt measuring system as claimed in claim 13 wherein the graphical indicators include a fixed circular ellipse and wherein the camera is in an effective position relative to the target surface for accurate measurements to be made when the guide ellipse is circular and coincides with the fixed circular ellipse.

15. The belt measuring system as claimed in claim 1 wherein the software program measures the longitudinal pitch (PLM) and the transverse pitch (PTM) of the repeated belt feature on the target surface from the measurement values and calculates the percent longitudinal elongation (E) of the conveyor belt asE = [RTL» (PLM / PTM) - 1)] *100%, where RTL is the ratio of the nominal transverse pitch to the nominal longitudinal pitch of the repeated belt feature.

16. The belt measuring system as claimed in claim 15 wherein the software program calculates the standard deviation of a set of the most recent measurement values and displays in the display screen a valid value of the percent longitudinal elongation of the conveyor belt when the standard deviation is a predetermined fraction of the measurement value.

17. The belt measuring system as claimed in claim 16 wherein the software program calculates a measurement error as plus or minus a multiple of the standard deviation and displays in the display screen the measurement error along with the valid percent longitudinal elongation of the conveyor belt.

18. The belt measuring system as claimed in claim 16 wherein the software program displays in the display screen the graphical indicators coincident with the valid value of the percent longitudinal elongation of the conveyor belt.

19. The belt measuring system as claimed in claim 1 wherein the software program transforms the target image frames by rotations and translations as necessary into transformed target image frames, in which the transformed target image frames are parallel to the target surface so that belt markers representing the locations of the repeated belt feature are aligned in orthogonal rows and columns in the transformed target image frames.

20. The belt measuring system as claimed in claim 1 comprising a handheld device housing the camera, the display, and the memory.

21. The belt measuring system as claimed in claim 20 wherein the handheld device is a smartphone and the software program is included in a smartphone app residing in the memory.

22. A method for measuring a conveyor belt, the method comprising: running a software program in a belt measuring system that includes a camera, a display screen, and a memory in which a belt database is stored; aiming the camera at a target surface on a conveyor belt to take target image frames of the target surface; wherein the software program executes program instructions in memory to: grab target image frames of the target surface as produced by the camera; perform correlations of a reference pattern of a repeated belt feature on a target surface of the conveyor belt in the belt database to the target image frames to identify locations of the repeated belt feature in the target image frames; determine the camera position relative to the target surface from the correlations; display on the display screen graphical indicators to guide the user in positioning the camera into an effective position relative to the target surface so that accurate measurements of the repeated belt feature can be made; measure the distance between the repeated belt features on the target surface from the correlations as a measurement value when the camera is in an effective position relative to the target surface.

23. The method of claim 22 wherein the software program measures the longitudinal pitch (PLM) and the transverse pitch (PTM) of the repeated belt feature on the target surface from the measurement values and calculates the percent longitudinal elongation (E) of the conveyor belt asE = [RTL» (PLM / PTM) - 1)] *100%, where RTL is the ratio of the nominal transverse pitch to the nominal longitudinal pitch of the repeated belt feature.

24. The method of claim 23 wherein the software program calculates the standard deviation of a set of the most recent measurement values and displays in the display screen a valid value of the percent longitudinal elongation of the conveyor belt when the standard deviation is a predetermined fraction of the measurement value.

25. The method of claim 24 wherein the software program calculates a measurement error as plus or minus a multiple of the standard deviation and displays in the display screen the measurement error along with the valid percent longitudinal elongation of the conveyor belt.

26. The method of claim 22 wherein the software program transforms the target image frames by rotations and translations as necessary into transformed target image frames, in which the transformed target image frames are parallel to the target surface so that belt markers representing the locations of the repeated belt feature are aligned in orthogonal rows and columns in the transformed target image frames.

27. The method of claim 22 comprising storing a plurality of reference patterns, each corresponding to a different belt style in the belt database.

28. The method of claim 27 comprising storing vision-processing settings corresponding to each reference pattern for customizing the processing of the target image frames for each belt style in the belt database.

29. A belt measuring system comprising: a handheld device including: a camera; a display screen; a memory in which a belt database including a plurality of reference patterns of repeated belt features on target surfaces of a plurality of conveyor belts of different belt styles is stored; a software program stored in memory that, when selected to run by a user, executes program instructions in memory to: grab target image frames produced by the camera of the target surface of a conveyor belt to be identified when the camera is aimed at the target surface by the user; perform correlations of the plurality of reference patterns to the repeated belt features in the target image frames to identify the belt style with the greatest correlation; display on the display screen the belt style with the greatest correlation.

30. The belt measuring system as claimed in claim 29 wherein the software program executes program instructions to determine the camera position relative to the target surfaces from the correlations and to display on the display screen graphical indicators to guide the user in positioning the camera into an effective position relative to the target surfaces so that accurate measurements of the repeated belt features can be made.

31. The belt measuring system as claimed in claim 29 wherein the handheld device is a smartphone and the software program is included in a smartphone app residing in the memory.

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