DEVICE AND METHOD FOR DETERMINING PROFILE DEPTH

Abstract

Device for measuring profile depth, comprising: an image sensor; a first and a second depth sensing module spaced apart from each other along a dividing axis, each comprising (i) an emitter configured to emit a beam of light, and (ii) an optical assembly configured to direct reflections of the beam of light onto a respective area of ​​the image sensor; a controller connected to the image sensor and configured, in response to the device crossing a profiled surface, to: receive a sequence of images from the image sensor corresponding to successive positions of the device crossing the profiled surface in a direction of movement substantially perpendicular to the dividing axis, the sequence of images representing subsequent reflections of the beams from the profiled surface;Determine, for each image in the sequence of images, a first depth measurement and a second depth measurement; and store the first and second depth measurements in a memory.

Description

BACKGROUND

[0001] Tire wear determines whether a tire needs to be replaced and is typically assessed by measuring tread depth. A worn tire has less tread depth and may need to be replaced. A tire's tread depth is typically measured manually with a tread depth gauge, but such measurements can be prone to inaccuracies or errors. Other tread depth measurement mechanisms, such as imaging-based systems, may misidentify the tire tread pattern, leading to inaccurate assessments of tire wear.

[0002] US 2017 / 0343337A1 describes a sensor device for measuring a surface, comprising an illumination device that emits a light beam, an optical device that splits the light beam into partial light beams and emits a first partial light beam toward a first surface area and a second partial light beam toward a second surface area. A light sensor is configured to receive a first surface reflection of the first partial light beam and a second surface reflection of the second partial light beam. A processor is configured to determine, based on the position of the first and second partial light beam reflections on the light sensor, the distance of the first surface area and the second surface area to the sensor device.

[0003] DE 10 2012 224 260 A1 describes a device for measuring the tread profile of a tire. It has several measuring modules arranged transversely to the tire's direction of travel and connected to a common evaluation unit. Each measuring module has at least one illumination device designed and arranged to project at least one line of light onto the profile to be measured during operation, and at least one image acquisition device designed to capture at least one image of at least one area of ​​the profile to be measured. The at least one illumination device and the at least one image acquisition device are designed and arranged such that the illumination direction of the illumination device and the image acquisition direction of the image acquisition device are neither parallel to each other nor orthogonal to the tire's tread.

[0004] WO 2016 / 118313A1 describes systems, devices, and methods for generating a fused depth map from one or more individual depth maps, wherein the fused depth map is configured to enable robust depth estimation for points within the depth map. The methods, devices, or systems may include components that identify the field of view (FOV) of an imaging device configured to acquire an image of the FOV and select a first depth acquisition method. The system or method can acquire a depth of the field of view relative to the imaging device using the first selected depth acquisition method and, based on the acquired depth of the first selected depth acquisition method, create a first depth map of the field of view.The system or procedure can also identify an area of ​​one or more points on the first depth map that has one or more inaccurate depth measurements and determine whether an additional depth measurement is required.

[0005] DE 197 05 047 A1 describes a method and a device for measuring the tread depth of a motor vehicle tire. The tire tread is illuminated by laser light from a laser source. The laser light creates a spot of light on the tread surface of the tire. The light reflected from the tire tread is detected by an image-resolving sensor. The image-resolving sensor observes the position and / or shape of the light spot. The signals from the image-resolving sensor are processed to generate output data based on the tread depth. During the measurement, the tire is rotated so that the measurement can be performed at multiple points on the tire tread. BRIEF DESCRIPTION OF THE DIFFERENT VIEWS OF THE DRAWINGS

[0006] The accompanying figures, in which identical reference numerals denote identical or functionally similar elements in the individual views, are incorporated into the disclosure together with the following detailed description and form an integral part of the disclosure and serve to further illustrate embodiments of concepts comprising the claimed invention described herein and to explain various principles and advantages of these embodiments. Fig. Figure 1A shows a computer device for capturing depth scanning data from a tire. Fig. 1B and Fig. 1C are schematic representations of the computer device of Fig. 1A during the acquisition of depth scan data. Fig. 2A is a block diagram of the depth sensing modules of the device. Fig. 1A-1C. Fig. 2B is a perspective view of a depth sensing module of the Fig. 2A. Fig. 2C is a block diagram of certain internal hardware components of the device. Fig. 1A-1C. Fig. Figure 3 is a flowchart of a procedure for measuring profile depth. Fig. 4 is a schematic diagram showing calibration data for use in the procedure of Fig. 3 shows. Fig. 5A-5B show image data acquired during the execution of the procedure by Fig. 3 were recorded. Fig. Figures 6A-6C demonstrate the determination of depth measurements from the image data of the Fig. 5A-5B. Fig. Figure 7A shows the interpolation of additional depth measurements during the execution of the procedure. Fig. 3. Fig. Figure 7B shows the generation of a combined set of depth measurements during the execution of the procedure of Fig. 3. Fig. 8 and Fig. Figure 9 shows an exemplary physical implementation of the device. Fig. 1A-1C and 2A-2B.

[0007] Experts will recognize that elements in the figures are shown for the sake of simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to improve the understanding of embodiments of the present invention.

[0008] Where appropriate, the apparatus and process components have been represented by conventional symbols in the drawings, which show only those specific details relevant to understanding the embodiments of the present invention, so as not to obscure the disclosure with details that are readily apparent to those skilled in the field who refer to the present description. DETAILED DESCRIPTION

[0009] Examples disclosed herein relate to a device for measuring profile depth, comprising: an image sensor; a first depth-sensing module comprising (i) a first emitter configured to emit a first beam of light, and (ii) a first optical assembly configured to direct reflections of the first beam of light onto a first region of the image sensor; a second depth-sensing module spaced apart from the first depth-sensing module along a dividing axis, the second depth-sensing module comprising (i) a second emitter configured to emit a second beam of light, and (ii) a second optical assembly configured to direct reflections of the second beam of light onto a second region of the image sensor;A controller connected to the image sensor and configured, in response to the device crossing a profiled surface in a direction of movement substantially perpendicular to the dividing axis, to: receive a sequence of images from the image sensor corresponding to successive positions of the device crossing the profiled surface in the direction of movement, the sequence of images representing subsequent reflections of the first and second beams from the profiled surface; determine a first depth measurement and a second depth measurement for each image in the sequence of images; and store the first and second depth measurements in a memory.

[0010] Further examples disclosed herein relate to a method for measuring a profile depth in a device comprising an image sensor, a controller, a first depth sensing module and a second depth sensing module spaced apart from the first depth sensing module along a dividing axis, the method comprising: emitting a first light beam from a first emitter of the first depth sensing module and directing reflections of the first light beam onto a first area of ​​the image sensor; emitting a second light beam from a second emitter of the second depth sensing module and directing reflections of the second light beam onto a second area of ​​the image sensor;at the control unit, in response to the device crossing a profiled surface in a direction of movement substantially perpendicular to the dividing axis: receiving a sequence of images from the image sensor corresponding to successive positions of the device crossing the profiled surface in the direction of movement, the sequence of images representing subsequent reflections of the first and second beams from the profiled surface; determining a first depth measurement and a second depth measurement for each image in the sequence of images; and storing the first and second depth measurements in a memory.

[0011] Fig. Figure 1A shows a profile measuring device 100 (here also simply referred to as device 100) configured to determine the tread depth of a profiled object, such as a tire 104. The tire 104 is shown in isolation but can be mounted on a vehicle, such as an automobile, van, trailer, or the like. In particular, the device 100 is configured to determine the depth of at least a subset of a plurality of treads on the tire 104. The treads on the tire 104 can include primary treads 108 and secondary treads 112. The primary treads 108 (of which the tire 104, as shown, has four) typically extend continuously around the circumference of the tire 104. The secondary treads 112, as shown in Fig. The 1A tread pattern may not extend continuously around the circumference of the tire 104. The smaller secondary tread patterns 112 may also have a shallower tread depth than the main tread patterns 108.

[0012] In the present example, the device 100 comprises a mobile computing device, such as a mobile computer (e.g., a handheld computer), equipped with depth-sensing modules that may be integrated into the device 100 or implemented in a discrete accessory mountable to the device 100. The device 100 is configured to measure tread depths by traversing (e.g., through manipulation by an operator) the tire 104 or other object with a tread pattern in a direction of movement “S”. In the present example, where the object to be scanned is the tire 104, the direction of movement S is parallel to an axis A of the tire (i.e., perpendicular to the main treads 108 in the illustrated example).

[0013] As in Fig. 1B and Fig. As shown in Figure 1C, the device 100 comprises a pair of depth-sensing modules, each containing a light emitter 116-1, 116-2 (hereinafter referred to as "emitter 116"). The device 100 also includes an image sensor 120, such as a linear charge-coupled device (CCD). The emitters 116 can be laser emitters or other suitable emitters of electromagnetic radiation, including optical emitters. The emitters 116 are configured to emit corresponding light beams 124-1, 124-2 (e.g., laser beams), the reflections of which 128-1 and 128-2 are detected by the image sensor 120. The depth-sensing modules also include optical assemblies (in the Fig. 1B and Fig. (Figure 1C omitted for clarity) to direct the reflections 128 onto corresponding areas of the image sensor 120. That is, reflection 128-1 is directed onto a first area of ​​the image sensor 120, while reflection 128-2 is directed onto a second area of ​​the image sensor 120. As will be apparent to those skilled in the art, the specific position at which each reflection 128 strikes the image sensor 120 within the corresponding area of ​​the image sensor 120 varies with the origin of the reflection 128 (i.e., with the depth and / or shape of the surface from which the reflection 128 originated).

[0014] As the device 100 traverses the surface of the tire 104 along the direction of motion S, a multitude of first and second reflections 128-1 and 128-2 are detected by the image sensor 120. Each pair of reflections 128-1 and 128-2 corresponds to a different position along the surface of the tire 104 in the direction of motion S. The device 100 is further configured to determine a depth D from the image sensor 120 to the point on the tire 104 where the corresponding reflection 128 originated, based on the position of the reflections 128 as detected by the image sensor 120 and the known position of the image sensor 120 relative to the emitters 116 and the aforementioned optical assemblies.

[0015] Before discussing the functionality of computer device 100 in detail, certain components of computer device 100 will be described with reference to the Fig. 2A and Fig. 2B described.

[0016] Fig. Figure 2A shows the aforementioned depth sensing modules 200-1 and 200-2 in greater detail. In particular, Fig. Figure 2A shows a top view of the device 100, with all modules except the depth sensing modules 200 and the image sensor 120 omitted, while the device 100 moves in the direction of movement S over the profiles 108 and 112 of the tire 104. A first depth sensing module 200-1 comprises the aforementioned first emitter 116-1 and a first mirror 202-1, which is configured to deflect the path of the beam 124-1 towards the tire 104 (i.e., into the side, as shown). The mirror 202-1 also deflects the reflection 128-1 from the tire 104 (away from the side, as shown) to a first optical assembly 204-1. The optical assembly 204-1 comprises one or more lenses, mirrors or the like and is configured to direct the reflection 128-1 onto the image sensor 120.The device 100 also includes a second depth-sensing module 200-2, which contains the second emitter 116-2, a second mirror 202-2, and a second optical assembly 204-2. In some embodiments, the mirrors 202-1 and 202-2 can be configured as a single mirror extending along both the first and second depth-sensing modules 200. In other embodiments, the emitters 116 and the optical assemblies 204 can be mounted within the device 100 such that they are directed directly at the tire 104, and the mirrors 202 can be omitted. As shown in... Fig. As shown in Figure 2A, the optical assemblies 204 are arranged at an angle relative to the rays 124 (i.e., the optical axes of the optical assemblies 204 are not parallel to the rays 124) in order to increase the utilization of the field of view of the optical assemblies 204.

[0017] As in Fig. As can be seen in 2A, the first and second depth sensing modules 200 are spaced apart from each other along a separating axis “X” by a predetermined distance, which is shown in Fig. 2A is represented as the distance between the optical axes of emitters 116-1 and 116-2 (i.e., the path along which rays 124-1 and 124-2 propagate from emitters 116-1 and 116-2, respectively). The X axis is essentially perpendicular to the direction of motion S (and thus essentially parallel to the main profiles 108). The separation of the depth-sensing modules results in each depth-sensing module collecting reflections 128 corresponding to a different area of ​​the tire 104 for a given position along the direction of motion S.

[0018] Fig. Figure 2B shows a perspective view of the isolated depth sensing module 200-2 (i.e., without the depth sensing module 200-1), in which the beam 124-2 is deflected by the mirror 202-2 towards the tire 104. After reflection of the beam 124-2 by the tire, a reflected portion of the beam 124-2 returns towards the mirror 202-2, where the reflection 128-2 is deflected towards the optical assembly 204-2, which in turn directs the reflection 128-2 onto the image sensor 120.

[0019] According to Fig. In addition to the components mentioned above, device 100 includes in 2C a central processing unit (CPU), also referred to as a depth processor 208, which is connected to a non-transient, computer-readable storage medium, such as a memory 212. The memory 212 comprises any suitable combination of volatile memory (e.g., random access memory (“RAM”)) and non-volatile memory (e.g., read-only memory (“ROM”), electrically erasable programmable read-only memory (“EEPROM”), flash memory). In general, the processor 208 and the memory 212 each comprise one or more integrated circuits.

[0020] The device 100 also includes at least one input device 216 connected to the processor 208. The input device 216 is configured to receive inputs and provide data representing the received inputs to the processor 208. The input device 216 includes a touchscreen, a keypad, a trigger button, a microphone, or a suitable combination thereof. The device 100 also includes a display 220 (e.g., a flat panel display integrated into the aforementioned touchscreen) connected to the processor 208 and configured to display data under the control of the processor 208. In addition to the display 220, the device 100 may also include one or more output devices, such as a speaker, a notification LED, and the like (not shown).

[0021] The device 100 also includes a communication interface 224, which is connected to the processor 208. The communication interface 224 includes any suitable hardware (e.g., transmitters, receivers, network interface controllers, and the like) that enables the device 100 to communicate with other computer devices via wired and / or wireless connections (e.g., via local or wide area networks, universal serial bus (USB) connections, and the like). The specific components of the communication interface 224 are selected based on the type(s) of network(s) or other connections through which the device 100 is to communicate.

[0022] The device 100 can also include a motion sensor 226 connected to the processor 208, such as an accelerometer, an inertial measurement unit (IMU) containing an accelerometer and a gyroscope, or the like. However, in other embodiments, the motion sensor 226 can be omitted.

[0023] The memory 212 of the device 100 stores a variety of applications, each containing a variety of computer-readable instructions that can be executed by the processor 208. The execution of the aforementioned instructions by the processor 208 causes the device 100 to implement a specific functionality, as discussed herein. The applications are therefore considered in the following discussion to be configured to perform this functionality. In the present example, the memory 212 of the device 100 stores a depth-sensing application 228, which is also referred to herein as application 228.The device 100 is configured to control the depth sensing modules via the execution of application 228 by processor 208. These modules collect image data representing reflections 128 as the device 100 crosses the tire 104 in the direction of movement S and generate depth measurements from the collected image data. The device 100 can also be configured to identify areas of interest from the depth measurements (e.g., corresponding to the main profiles 108), as will be explained in more detail below.

[0024] In other examples, the processor 208, as configured by the execution of the application 228, is implemented as one or more specially configured hardware elements, such as field-programmable gate arrays (FPGAs) and / or application-specific integrated circuits (ASICs). In still other embodiments, which will be discussed in more detail below, the functionality of the device 100 can be implemented in various physical devices that work together to obtain the depth measurements mentioned above.

[0025] The functionality implemented by the device 100 via the execution of the application 228 is now described with reference to Fig. 3 described in more detail. Fig. Figure 3 illustrates a method 300 for measuring a profile depth. The method 300 is described in connection with its implementation by the device 100, in particular by way of the implementation of application 228 and with reference to the information in the Fig. 1B, Fig. 1C, Fig. 2A and Fig. The components shown in 2B are described.

[0026] In block 305, the device 100 is configured to load calibration data for the depth sensing modules. The calibration data can be stored, for example, in memory 212 using application 228. The calibration data defines physical relationships between the emitter 116 and the optical assembly 204 of each depth sensing module, as well as the image sensor 120. Specifically, in Fig. Figure 4 shows a simplified representation of the image sensor 120 and a depth sensing module (without the mirror 202). As in Fig. As can be seen in Figure 4, the angle of reflection produced by an emitted beam 124 varies with the depth at which the reflection is generated, as well as with the shape of the reflecting surface (e.g., a tread 108 or 112 of the tire 104). Two example reflections 128a and 128b are shown, generated at different depths (i.e., the surfaces, such as the tire treads 108 or 112, are shown at different depths). The reflections 128a and 128b pass through the optical assembly 204 and are directed onto the image sensor 120 at different positions. Thus, the depth at which a reflection 128 was generated can be determined from the position of the reflection on the image sensor 120. For example, reflection 128b strikes the image sensor at point "xb".

[0027] To determine the depth at which a reflection 128 originated from image sensor data, the optical assembly 204 can be modeled as a pinhole aperture at point 400. The depth at which a reflection 128 originated can then be determined with knowledge of the distance "b" between point 400 and the line along which the beam 124 propagates, as well as the distance "f" from point 400 to the image sensor 120. For example, the depth of reflection 128b can be determined by calculating the product of the distance f and the position of point xb along the x-axis, as measured by the beam 124. The aforementioned product is then divided by the difference between the position of xb and the distance "b". The calibration data loaded in block 305 can therefore contain the values ​​for "f" and "b" as determined empirically, e.g., during the manufacture of the device 100.

[0028] Back to Fig. In block 310, the device 100 is configured to determine whether to initiate a depth scan. The determination in block 310 may include determining whether an input command has been received from the input device 216, such as a trigger pull, the selection of a command element via a touchscreen, or the like. In other embodiments, the determination in block 310 includes collecting depth measurements and initiating a scan if the depth measurements fall within a predefined range indicating that the device 100 has been placed on an object such as the tire 104. If the determination in block 310 is negative, the device 100 waits to initiate a scan.

[0029] If the determination in block 310 is positive, the device 100 is configured to activate the emitters 116 in block 315 and receive image data from the image sensor 120. In particular, the image data received in block 315 shows a reflection 128-1 of the first beam 124-1 in the first section of the image sensor 120 and a reflection 128-2 of the second beam 124-2 in the second section of the image sensor 120. As explained in more detail below, receiving an image (frame) from the image sensor containing representations of a first reflection and a second reflection provides a sample from which depth measurements can be generated (in particular, two depth measurements, one for each depth sensing module). In block 320, the device 100 is configured to determine whether the scanning process is complete. The completion of the scanning can be indicated by releasing an input, such as a signal. B. the trigger mentioned above, or through another input, such as e.g.The selection of a stop command via a touchscreen is displayed. In some examples, the device 100 can terminate the scanning process if, for example, the motion sensor 226 indicates movement of the device that deviates from the direction of movement S beyond a threshold. For example, if the angular orientation of the device 100 changes by more than a predetermined threshold (indicating that the device is tilting, yaw, and / or rolling while crossing the tire 104), the device 100 can terminate the scanning process and generate a warning via the display 220 or another suitable output device. In such cases, instead of continuing with block 325, the device 100 can simply terminate the execution of procedure 300.

[0030] If the determination in block 320 indicates that the scan is incomplete, blocks 315 and 320 are repeated. In other words, another sample is captured by the image sensor 120, including another image (frame) representing another first reflection 128-1 and another second reflection 128-2. The reflections 128, represented in each successive frame of the image data captured in block 315, correspond, as is now clear, to successive positions on the tire 104 along the direction of travel S. Taken together, the image data captured by repeated execution of block 315 thus represent a profile of the surface of the tire 104 along the direction of travel S.

[0031] In Fig. 5A represents a set of 500 images, beginning with image 504 and ending with image 508. That is, the set of 500 images represents the image data collected by successive executions of block 315 during a depth scan, and thus each image in the set of 500 corresponds to a specific position on the tire 104 along the direction of movement S. Image 504 contains a representation 512-1 of a first reflection 128-1 and a representation 512-2 of a second reflection 128-2 in specific sections of the image (separated by the dashed line in Fig. 5A). As in Fig. As shown in Figure 5A, the position of certain representations 512 within the image data changes with the position along the direction of motion S in which each image was acquired. Changes in the position of a particular reflection (e.g., representations 512-1, in the example shown) indicate changes in depth along the direction of motion S.

[0032] Fig. Figure 5B shows the position of set 500 of images within a larger set 516 of images collected as the device 100 crosses the tire 104 along the direction of movement S. Set 516 can be combined into a single image, for example, by appending images to the single image after each execution of block 315, or by combining the images after a positive determination in block 320. As shown in Fig. As can be seen in 5B, the position changes of the representation 512-1 can correspond to a part of a secondary profile 112 via the set 500 of images, while the static position of the representation 512-2 in the images 500 can correspond to a part of the tire 104 without profiles.

[0033] Back to Fig. 3. In block 325, after the depth scanning is complete, the device 100 can be configured so that the intensity of the representations of the reflections 128 (e.g., those in Fig. The representations shown in Figure 5A (512) are normalized, for example, to distribute the representations over a predetermined intensity range. For instance, the normalization process can distribute the representations over a wider intensity range than is present in the raw data collected in Block 315, which can only contain low intensities. The representations (512) can contain one or more pixels, each with one or more color and / or intensity values. For example, each pixel can contain a grayscale value between zero (indicating black or no reflection) and 255 (indicating white or a reflection at maximum intensity). As can now be seen by those skilled in the art, the reflections (128) shown in the image data can vary in intensity according to the depth at which the reflections (128) originated (greater depths resulting in lower intensities in the image data).For example, the device 100 can be configured to apply a function to the image data that adjusts the intensity of each pixel in the image according to its position on the image sensor as a representative of the angle at which the reflection 128 arrived at the optical assembly 204. The function can be based, for example, on Lambert's law. Various other intensity normalization mechanisms can also be used in block 325. In other examples, block 325 can be omitted.

[0034] In block 330, the device 100 is configured to perform a scan for each sample of image data (e.g., for each of the images in Fig. (Images 5A shown) a first depth measurement corresponding to the first reflection 128-1, as shown in Figure 512-1, and a second depth measurement corresponding to the second reflection 128-2, as shown in Figure 512-2, is determined. In other examples, block 330 can also be performed for each captured image immediately after block 315.

[0035] Determining the depth measurements in block 330 can involve selecting a measurement point for each representation 512. As can now be seen, the reflections 128 typically act on the image sensor 120 at a multitude of pixel positions, and the representations 512 therefore show several candidate depths (one for each pixel with a non-zero intensity). The device 100 can therefore be configured, for example, to select the pixel with a peak intensity from each representation 512. In other examples, the device 100 can be configured to determine the midpoint of each representation 512 and determine a depth measurement based on the position of the midpoint on the image sensor 120. Fig. 6A, for example, shows part of an image 600 that contains a representation 612 of a reflection 128. As in Fig. As shown in Figure 6A, the representation contains 612 pixels with different intensities. In block 330, the device 100 can be configured to select the pixel with the highest intensity, which is shown in Fig. 6B is represented as point 616. Based on the position of point 616 along the separation axis X (which is also the longitudinal axis of the linear image sensor 120), the device 100 is configured to determine a depth corresponding to point 616. For example, the device 100 can be configured with reference to the one associated with Fig. The distances “b” and “f” discussed in section 4 can be configured to determine the depth for a measurement point by calculating the product of the point’s position “x” along the dividing axis X and the distance “f”, and dividing the product by the difference between the position “x” and the distance “b”. That is, the depth “y” can be determined according to (xf) / (xb).

[0036] Device 100 is configured to repeat the aforementioned process for each representation of a reflection in each of the images collected via Block 315. That is, since each image contains representations of a first reflection 128-1 and a second reflection 128-2, the device in Block 330 determines first and second depth measurements according to each image. As shown in Fig. As shown in Figure 6C, block 330 generates a first array 620 of depth measurements corresponding to the reflections 128-1 from successive positions on the tire 104 along the direction of movement S. The execution of block 330 also generates a second array 624 of depth measurements corresponding to the reflections 128-2 from the aforementioned successive positions on the tire 104 along the direction of movement S. The first and second arrays 620 and 624 of depth measurements may contain non-matching depth measurements. As shown, for example, the first array contains 620 depth measurements of 5 / 32 inch, 5 / 32 inch, 6 / 32 inch for a sequence of three positions along the direction of movement S, while the second array contains 624 depth measurements of 0 / 32 inch for the same sequence of positions, indicating that no profile 108 or 112 was captured at these positions by the second depth sensing module.For example, a secondary profile 112 and a primary profile 108 may have been located in the path of the first beam 124-1, while only the primary profile 108 may have been located in the path of the second beam 124-2, with the secondary profile 112 ending between the first and second depth sensing assemblies. As can be seen, the depth of the outer surface of the tire 104 need not be specified as zero. In the present example, the device 100 is configured such that the depth measurements are normalized to the surface of the tire 104. In other examples, however, such normalization can be omitted.

[0037] Back to Fig. 3. After generating depth measurements in block 330, the device 100 is configured to store the depth measurements in memory 212. The depth measurements can be stored, for example, for later transfer to another computer device, for display on the display 220, or the like. The device 100 can also be configured to perform additional processing in connection with the depth measurements before such transfer or display. In particular, in block 335, the device 100 is configured to determine updated positions for each of the depth measurements based on motion data collected during the execution of block 315.

[0038] In particular, the device 100 in block 315 can be configured to acquire a series of acceleration measurements via the motion sensor 226, along with the image data mentioned above. The acceleration measurements and the image data collected in block 315 (and thus the depth measurements derived from the image data in block 330) are correlated with each other by timestamps. The device 100 is configured to generate a position corresponding to each depth measurement, based on the assumption that the velocity of the device 100 is zero at the start of the scan (in block 310) and on the acceleration measurements. The resulting updated positions may indicate that the depth measurements do not correspond to uniformly spaced positions along the direction of motion S. Fig. 7A, for example, represents an initial array of depth measurements 700, which are assumed to be evenly spaced along the direction of movement S.

[0039] Based on the acceleration measurements, updated positions are assigned to the depth measurements in the array 700. As in Fig. As shown in Figure 7A, this generates an updated array 704 of depth measurements, in which measurements 708 and 712 are assigned corresponding positions that do not correspond to their originally assumed positions (as shown in array 700). The updated positions of array 704 indicate that the device 100 did not move at a constant speed through the depth scan while acquiring the first four samples, but rather accelerated.

[0040] In block 335, the device 100 can also be configured to resample the depth measurements by interpolating depth measurements at additional intermediate positions between those determined from the motion data. For example, in block 335, another updated array 716 of depth measurements can be generated in which depth measurements 720 and 724, which are evenly spaced from the other depth measurements, are interpolated from the surrounding depth measurements of array 704, based on the depth and positions of these surrounding depth measurements.

[0041] Back to Fig. In Block 340, Device 100 can also be configured to generate a single combined array of depth measurements from the first and second arrays mentioned above (e.g., arrays 620 and 624, or updated versions thereof, obtained via Block 335). As mentioned above, in some cases, for example, beams 124-1 and 124-2 both traverse the main profiles 108, while only one beam 124 traverses a secondary profile 112. In the present example, Device 100 in Block 340 is configured to generate a combined array of depth measurements by discarding depth measurements that indicate a discrepancy between arrays 620 and 624.

[0042] For example, the device 100 can be configured to determine, for each position along the direction of movement S, the first and second depth measurements from the first and second arrays 620 and 624 to determine whether a difference between the first and second depth measurements exceeds a predetermined threshold corresponding to a minimum desired resolution of the profile depth measurement (e.g., 1 / 32 inch). If the determination is positive, indicating a discrepancy between the arrays 620 and 624, the device 100 is configured to select one of the first and second measurements to retain for the combined array of depth measurements. In the present example, where the discrepancy is assumed to arise from the detection of a secondary profile 112 by a depth sensing module, the device 100 can be configured to select the measurement with the shallowest depth (i.e.,(ignoring the small profile). This embodiment is in . Fig. Figure 7B shows three depth measurements 728 from array 620 being discarded in a combined array 732. In other embodiments, the device 100 is configured to retain the measurements with the greatest depth, rather than those with the smallest depth.

[0043] If the difference between the first and second depth measurements for a given position does not exceed the threshold mentioned above, the first and second depth measurements are substantially similar, although they need not be exactly the same. If there is substantial similarity between the depth measurements of arrays 620 and 624, the device 100 can be configured to generate an average of the first and second depth measurements if they do not match (but differ by less than the threshold mentioned above), or to select either the maximum or the minimum of the measurements for use in the combined array 732. In other examples, the device 100 is configured to retain both depth measurements in the event of a discrepancy between the first and second depth measurements for a given position.This means that the combined array 732 can contain pairs of depth measurements for specific positions.

[0044] After the execution of block 340, the device 100 is configured to store the combined array 732 of depth measurements for display on the display 220 and / or to transfer to another computer device.

[0045] As already mentioned, the depth sensing modules can be integrated into the device 100 or implemented in a discrete accessory that can be mounted on the device 100. With regard to the Fig. 8 and Fig. Figure 9 shows an implementation in which the depth sensing modules are arranged in such an accessory.

[0046] In particular, it testifies Fig. 8 a mobile computing device 800, such as a smartphone, and an accessory 804. The mobile computing device 800 comprises a housing that carries a display 820 and an input device 816, such as a touchscreen integrated into the display, one or more selectable buttons, or the like. The accessory 804 comprises an inner surface 806 that carries a locking mechanism 808 configured to be releasably inserted into a rear surface 824 (see Fig. 9) the device 800 engages. The accessory 804 also includes a communication port 810 on its inner surface 806, which is configured to allow control of the accessory 804 via a corresponding port 828 (see Fig. 9) on the rear surface 824 is connected to the device 800. The connector 810, in conjunction with the connector 828, enables the accessory 804 to communicate with the device 800 and to receive electrical power from it. In other examples, the accessory 804 may contain a battery or other internal power source, and the connectors 810 and 828 may only enable communication, not both communication and power supply. In various embodiments, the communication connectors 810 and 828 are pogo connectors, USB connectors, USB-C connectors, or the like.

[0047] With reference to Fig. 9 comprises an outer surface 900 of the accessory 804, a window 904 through which the rays 124 exit and the reflections 128 enter. That is, the accessory 804 contains the aforementioned first and second depth sensing modules, as well as the processor 208, the memory 212, the image sensor 120, and the motion sensor 226. The device 800, on the other hand, can implement the aforementioned input device 216 and the display 220 (via the in Fig. 8 (input device 816 and display 820 shown). The device 800 can therefore output scan start and stop commands to the accessory 804 via the ports 810 and 828 and can also be configured to receive depth measurements from the accessory 804 for display on the display 820, for transmission to another computing device or the like.

[0048] Also in Fig. As shown in Figure 9, recesses 906 are located on the rear surface 824 of the device 800, which are in the Fig. The locking mechanism 808 shown in Figure 8 engages when the inner surface 806 of the accessory 804 engages with the rear surface 824 of the device 800 (e.g. by placing the accessory 804 against the rear surface 824 in a direction indicated by the dashed arrows 907).

[0049] The accessory 804 may also have one or more rails 908 on its outer surface 900, extending at least along a portion of the outer circumference of the rear surface 900. When the accessory 804 is engaged with the device 800 during use, the rails 908 are placed against the tire 104 (or any other profiled object to be scanned) upon initiation of a scan, in order to slide along the profiled surface of the tire 104 in the direction of movement S, in order to keep the depth-sensing modules at a predefined depth from the surface of the tire 104 and to prevent scratches or other damage to the window 904.

[0050] The height H of the rails 908 adjacent to the window 904 is selected according to a range of depths for which the depth sensing modules 200 are configured. The range of depths measurable by the depth sensing modules 200 is defined by the field of view and focal length of the optical assemblies 204, as well as by the size of the image sensor. At depths closer to the optical assemblies 204 than the aforementioned range, the reflections 128 may be less focused, while at depths farther from the optical assemblies 204 than the aforementioned range, the reflections 128 may be subject to measurement noise. Therefore, the height H of the rails 908 is selected such that the optical assemblies 204 are located at a distance above the tire 104 (i.e., at a depth from the outer surface of the tire 104) that is essentially equal to the minimum depth of the aforementioned range.For example, if the depth sensing modules 200 are configured to measure depths between 15 mm and 50 mm, the height H of the rails 908 next to the window 904 is chosen such that the optical assemblies 204 are approximately 15 mm away from the outer surface of the tire 104 when the rails 908 are engaged with the tire 104.

[0051] Variations to the above devices and methods are conceivable. For example, in some embodiments, the determination of the depth measurements, as described above in conjunction with Block 330, can be carried out immediately after each execution of Block 315. In such embodiments, the termination of the scanning (i.e., a positive determination in Block 320) can be initiated after a determination that the depth measurements have exceeded a termination threshold, indicating that the device 100 has probably been pulled away from the tire 104.

[0052] Specific embodiments have been described in the foregoing description. However, a person skilled in the art will recognize that various modifications and alterations can be made without altering the scope of protection of the invention as defined in the claims below. Accordingly, the description and figures are to be regarded in an illustrative rather than a limiting sense, and all such modifications are to be included within the scope of the present teachings.

[0053] The benefits, advantages, solutions to problems, and all elements that may lead to the occurrence or enhancement of a benefit, advantage, or solution are not to be understood as critical, necessary, or essential features or elements in some or all of the claims. The invention is defined solely by the attached claims, including any amendments made during the pendency of this application and all equivalents of the granted claims.

[0054] Furthermore, in this document, relational terms such as first and second, upper and lower, and the like may be used merely to distinguish one entity or action from another, without necessarily requiring or implying any actual relationship or order of such an entity or action between such entities or actions. The expressions "includes," "comprising," "has," "have," "exhibits," "exhibiting," "contains," "containing," or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, procedure, product, or device that includes, has, exhibits, or contains a list of elements may not only have those elements but may also have other elements not expressly listed or inherent in such process, procedure, product, or device. An element that "includes," "has," "exhibits," or "contains"The use of the term "a" does not, without further limitations, preclude the existence of additional identical elements in the process, method, product, or device that comprises, has, features, or contains the element. The terms "a" and "a" are defined as one or more unless expressly stated otherwise herein. The terms "essentially," "generally," "approximately," "about," or any other version thereof are defined in such a way as to be understood by a person skilled in the art in this field, and in one non-restrictive embodiment, the expression is defined as within 10%, in another embodiment as within 5%, in yet another embodiment as within 1%, and in yet another embodiment as within 0.5%. The term "coupled," as used herein, is defined as connected, but not necessarily directly and not necessarily mechanically.A device or structure that is “designed” in a certain way is at least also designed in that way, but may also be designed in ways that are not listed.

[0055] It is understood that some embodiments may include one or more generic or specialized processors (or “processing devices”) such as microprocessors, digital signal processors, custom processors, and field-programmable gate arrays (FPGAs), and uniquely stored program instructions (including both software and firmware) that control the one or more processors to implement, in conjunction with certain non-processor circuitry, some, most, or all of the functions of the method and / or device described herein. Alternatively, some or all of the functions may be implemented by a state machine that does not have any stored program instructions, or in one or more application-specific integrated circuits (ASICs) in which each function, or some combinations of certain functions, are implemented as user-defined logic.Of course, a combination of the two approaches can be used.

[0056] Furthermore, an embodiment may be implemented as a computer-readable storage medium on which computer-readable code is stored for programming a computer (which, for example, includes a processor) to execute a method as described and claimed herein. Examples of such computer-readable storage media include, but are not limited to, a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a ROM (read-only memory), a PROM (programmable read-only memory), an EPROM (erasable programmable read-only memory), an EEPROM (electrically erasable programmable read-only memory).Furthermore, it is assumed that an average professional, regardless of possible significant effort and many design choices motivated, for example, by available time, current technology, and economic considerations, will be readily able to generate such software instructions, programs, and ICs with minimal experimentation if guided by the concepts and principles disclosed herein.

[0057] The summary of the disclosure is provided to enable the reader to quickly ascertain the essence of the technical disclosure. It is provided with the understanding that it is not intended to be used for interpreting or limiting the scope or meaning of the claims. Furthermore, it can be inferred from the preceding detailed description that various features in different embodiments have been summarized for the purpose of streamlining the disclosure. This type of disclosure is not to be interpreted as reflecting the intention that the claimed embodiments require more features than are expressly stated in each claim. Rather, as the following claims demonstrate, the inventive step lies in fewer than all the features of a single disclosed embodiment.The following claims are hereby incorporated into the detailed description, each claim being a separately claimed subject matter.

Claims

[1] Device (100) for measuring a profile depth, comprising: an image sensor (120); a first depth sensing module (200-1) comprising (i) a first emitter (116-1) configured to emit a first light beam (124-1) and (ii) a first optical assembly (204-1) configured to direct reflections (128) of the first light beam (124-1) onto a first area of ​​the image sensor (120); a second depth sensing module (200-2) spaced apart from the first depth sensing module (200-1) along a separation axis (X), the second depth sensing module (200-2) comprising (i) a second emitter (116-2) configured to emit a second light beam (124-2), and (ii) a second optical assembly (204-2) configured to direct reflections (128) of the second light beam (124-2) onto a second area of ​​the image sensor (120); a controller connected to the image sensor (120) and configured to respond to the device (100) crossing a profiled surface in a direction of movement (S) substantially perpendicular to the dividing axis (X): Receiving a sequence of images from the image sensor (120) corresponding to successive positions of the device (100) crossing the profiled surface in the direction of movement (S), wherein the sequence of images represents subsequent reflections (128) of the first and second beams (124-1, 124-2) from the profiled surface; Determine, for each image in the sequence of images, a first depth measurement and a second depth measurement; and Storing the first and second depth measurements in a memory (212). [2] Device (100) according to claim 1, wherein the control is further configured to: Generate, for each pair of first and second depth measurements, a single combined depth measurement; and Storing the combined depth measurements in memory (212). [3] Device (100) according to claim 2, wherein the control for each pair of first and second depth measurements is further configured to: Determine whether a difference between the first and second depth measurements exceeds a threshold; and If the determination is positive, generate the single combined depth measurement by discarding one of the first and second depth measurements. [4] Device (100) according to claim 2, wherein the control for each pair of first and second depth measurements is further configured to: Determine whether a difference between the first and second depth measurements exceeds a threshold; and If the determination is negative, generate the individual combined depth measurement by averaging the first and second depth measurements. [5] Device (100) according to claim 1, further comprising a motion sensor (226), wherein the control is further configured to: Receiving an acceleration measurement from the motion sensor (226) that corresponds to each image in the sequence of images; and Determine an updated position along the direction of motion (S) for each of the first and second depth measurements based on the acceleration measurements. [6] Device (100) according to claim 5, wherein the control is further configured to generate an interpolated depth measurement which corresponds to an intermediate position between a pair of updated positions. [7] Device (100) according to claim 1, further comprising a rail configured to engage slidably with the profiled surface. [8] Device (100) according to claim 1, further comprising: an accessory housing that carries the first and second depth sensing modules (200-2), the image sensor (120) and the control unit. [9] Device (100) according to claim 8, wherein the accessory housing comprises a locking mechanism for releasably engaging a mobile computer device. [10] Device (100) according to claim 9, wherein the control is further configured to transmit the first and second depth measurements to the mobile computer device. [11] Method for measuring a profile depth in a device (100) comprising an image sensor (120), a controller, a first depth sensing module (200-1) and a second depth sensing module (200-2) spaced apart from the first depth sensing module (200-1) along a dividing axis (X), the method comprising: Emitting a first light beam (124-1) from a first emitter (116-1) of the first depth sensing module (200-1) and directing reflections (128) of the first light beam (124-1) onto a first area of ​​the image sensor (120); Emitting a second light beam (124-2) from a second emitter (116-2) of the second depth sensing module (200-2) and directing reflections (128) of the second light beam (124-2) onto a second area of ​​the image sensor (120); at the control, in response to the fact that the device (100) crosses a profiled surface in a direction of movement (S) substantially perpendicular to the separation axis (X): Receiving a sequence of images from the image sensor (120) corresponding to successive positions of the device (100) crossing the profiled surface in the direction of movement (S), wherein the sequence of images represents subsequent reflections (128) of the first and second beams (124-1, 124-2) from the profiled surface; Determine, for each image in the sequence of images, a first depth measurement and a second depth measurement; and Storing the first and second depth measurements in a memory (212). [12] Method according to claim 11, further comprising, on the control: Generating a single combined depth measurement for each pair of first and second depth measurements; and Storing the combined depth measurements in memory (212). [13] Method according to claim 12, further comprising, on the control: for each pair of first and second depth measurements: Determine whether a difference between the first and second depth measurements exceeds a threshold; and If the determination is positive, generate the single combined depth measurement by discarding one of the first and second depth measurements. [14] Method according to claim 12, further comprising, on the control: for each pair of first and second depth measurements: Determine whether a difference between the first and second depth measurements exceeds a threshold; and If the determination is negative, generate the individual combined depth measurement by averaging the first and second depth measurements. [15] Method according to claim 11, further comprising, on the control: Receiving an acceleration measurement from a motion sensor (226) of the device (100), corresponding to each image in the sequence of images; and Determine an updated position along the direction of motion (S) for each of the first and second depth measurements based on the acceleration measurements. [16] Method according to claim 15, further comprising, on the control: Generating an interpolated depth measurement that corresponds to an intermediate position between a pair of updated positions. [17] Method according to claim 11, further comprising, on the control: Transferring the first and second depth measurements to a mobile computer device.

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