The present disclosure relates generally to the automotive field. More particularly, the present disclosure relates to deformable radar polygon systems and methods for a virtual bumper.
Vehicles have been equipped with ultrasonic sensors (USSs) for years as part of their Advanced Driver Assistance Systems (ADASs). These sensors have been primarily used for parking guidance and blind spot detection. Parking applications rely upon USS data to detect open parking spots, and autonomous vehicles use USS data to detect conditions around the vehicle. The detection results of USSs are presented as an occupancy grid, where the pixel value of a covered region is 1, and otherwise 0. One big concern for a USS-based occupancy grid is the relatively short detection range and high false alarm rate because of air changes (temperature, wind, etc.), which makes the occupancy grid non-coherent across time and worsens the performance of a route planning algorithm used in an automatic parking application. Further, a conventional USS-based occupancy grid requires significant memory consumption.
To solve this problem, the present disclosure adds automotive millimeter-wave (mmWave) radars to the current perception system and makes them an effective augmentation for USSs. There are several reasons for using such radar sensors, including good penetration ability and robustness to environmental changes. First, relying on the superior range and Doppler resolution, mmWave radars generate denser point clouds than the intersection detections of USSs, making it possible to form a more robust and accurate radar occupancy grid. Second, the radar occupancy grid can be formulated as a polygon with multiple nodes. The region within the polygon is assumed as the safety region (i.e., equivariant to have pixel value 0), and the region outside of the polygon is assumed as the covered/dangerous region. In this way, the memory-consuming occupancy grid is simplified as a polygon that consists of a bunch of points, which can be used in the downstream application for relieving computational burden. e.g., route planning, collision avoidance, etc. Third, mmWave radars measure and estimate the Doppler velocity of detected targets such that one can assign a moving velocity to each node of the radar polygon. This makes it possible to predict the shape of a future radar polygon and feed the predicted radar polygon to downstream applications. A polygon with predictable shape change is referred to herein as a “deformable polygon.” If a real vehicle bumper absorbs impact upon a collision, the virtual vehicle bumper of the present disclosure provides a protection area provided by the vehicle perception system using radar sensors that complement the USS occupancy grid.
The present disclosure develops and utilizes a radar polygon formation algorithm using point cloud input, compares the performance of the radar polygon and USS occupancy qualitatively and quantitatively, and verifies the deformable polygon idea in real applications with collected data.
In one illustrative embodiment, the present disclosure provides a system, including: memory storing instructions executed by a processor to project a 3D x-y-z point cloud into a 2D plane by selecting all points with a predetermined height and projecting the points to a 2D x-y plane by compressing the heights, sampling each azimuth direction with a fixed angle Δθ, for each sampling sector, selecting a closest point, if it exists, and locating a virtual point at a boundary otherwise, and connecting all selected points in sequence to form a deformable radar polygon.
In another illustrative embodiment, the present disclosure provides a method, including: projecting a 3D x-y-z point cloud into a 2D plane by selecting all points with a predetermined height and projecting the points to a 2D x-y plane by compressing the heights, sampling each azimuth direction with a fixed angle Δθ, for each sampling sector, selecting a closest point, if it exists, and locating a virtual point at a boundary otherwise, and connecting all selected points in sequence to form a deformable radar polygon.
In a further illustrative embodiment, the present disclosure provides a non-transitory computer-readable medium comprising instructions stored in a memory and executed by a processor to carry out the steps, comprising: projecting a 3D x-y-z point cloud into a 2D plane by selecting all points with a predetermined height and projecting the points to a 2D x-y plane by compressing the heights, sampling each azimuth direction with a fixed angle Δθ, for each sampling sector, selecting a closest point, if it exists, and locating a virtual point at a boundary otherwise, and connecting all selected points in sequence to form a deformable radar polygon.
The present disclosure is illustrated and described herein with reference to the various drawings, in which:
In general, radar is preferable to USSs for the following reasons:
To generate a deformable radar polygon, the following steps are provided: (1) initial formation via sampling, (2) predictable polygon change according to Doppler velocity, and (3) smoothing using history memory.
Since the present disclosure is interested in the occupancy grid in the 2D bird’s-eye-view (BEV), the first step is to project a 3D x-y-z point cloud into the 2D plane. That is, one selects all points with reasonable height (e.g., greater than -1.5 m and less than 3 m) and projects them to the 2D x-y plane by compressing the height. Then, each azimuth direction is sampled with fixed angle Δθ, as illustrated in
Related to the deformable polygon and polygon prediction, the nodes that constitute the radar polygon have Doppler velocity, which can describe their instant movement along the radial direction (i.e., the direction from node to radar). By assuming that the moving velocity of a node/point is constant within a short period of time, one can estimate the future location of a node by calculating and adding its radial movement using current Doppler velocity. That is, for a node point with location (x, y) and Doppler velocity v detected by radar sensor (xs, ys), its radial movement (Δx, Δy) within duration Δt is given by:
Therefore, by adding the estimated radial movement to the node point, one can predict its new location (x′,y′) = (x, y) + (Δx,Δy). It is worth noting that one can predict the future-frame radar polygon based on the current polygon and the radar polygon is “deformable” as the predictable shape changes. That is, one can predict the new location of each point of current polygon as above (ignoring the movement of the virtual points) and connect all predicted nodes to form the new polygon.
The above provides how to generate the radar polygon using the point cloud of one frame and how to predict the polygon for future frames. Due to noise and multi-path issues, there always exist false alarms and missing detections in radar point clouds, which can make radar polygons incoherent across frames/time. To smooth the generated polygons across time,
Now, as illustrated in
Thus, assuming the polygon is sorted (in azimuth angle) with vertices (x1, y1), (x2, y2), ... (xn, yn), and the point that needs to be checked is (a, b), then a detection function F is defined as Equation (1).
where
and
is the Hadamard product (element-wise multiplication). The output of F is a column vector, and one needs to check the sign of each vector element to make a decision. That is, one finds a point (a0, b0) that needs be located within the polygon and checks if the vector F(a, b) has the same sign as F(a0, b0). If yes, then the point (a, b) is located within the polygon as well. If no, then (a, b) is outside of or on the polygon.
Equation (1) can be simplified to matrix-represented Equation (2) using matrix P, vector Xn = [x1, x2, ... xn]T and Yn = [y1, y2, ... yn]T.
In terms of the evaluation testbed,
Experiments were performed at a parking lot and indoor garage with a classic car backing off scenario. After implementing the proposed algorithm on a collected radar point cloud, the radar polygon results were obtained with comparison to USS occupancy grids, with qualitative and quantitative evaluations provided as below.
Comparing radar and USS in the parking scenario, one shot from the resulting radar polygon video is shown in the middle of
As compared to the USS, the radar polygon covers larger field of view within the BEV image since the detectable range of radar is almost 5 times larger than that of a USS. When one shrinks the radar detectable range to 5 m (the same as a USS), the corresponding radar polygon is presented in the right of
The radar detection capability was verified for pedestrians around the parked vehicle by showing the sequence of radar polygon results in
The deformable radar polygon concept was verified by one-to-one comparing the ground truth radar polygon and the predicted polygon from the last frame. One example is illustrated in the first column of the table of
In the table of
Thus, the present disclosure details the proposed radar polygon formation algorithm using point cloud input, compares the performance of radar polygon and USS occupancy qualitatively and quantitatively. The results show that the radar polygon generated by four radars is more robust and accurate than the USS occupancy grid generated by twelve USSs. The deformable polygon idea is verified by showing high IoU correlation between the predicted radar polygon and ground truth using real collected data.
It is to be recognized that, depending on the example, certain acts or events of any of the techniques described herein can be performed in a different sequence, may be added, merged, or left out altogether (e.g., not all described acts or events are necessary for the practice of the techniques). Moreover, in certain examples, acts or events may be performed concurrently, e.g., through multi-threaded processing, interrupt processing, or multiple processors, rather than sequentially. It should be noted that the algorithms of the present disclosure may be implemented on an embedded processing system running a real time operating system (OS), which provides an assured degree of availability and low latency. As discussed below, processing in a cloud system may also be implemented if such availability and latency problems are addressed.
Again, the cloud-based system 100 can provide any functionality through services, such as software-as-a-service (SaaS), platform-as-a-service, infrastructure-as-a-service, security-as-a-service, Virtual Network Functions (VNFs) in a Network Functions Virtualization (NFV) Infrastructure (NFVI), etc. to the locations 110, 120, and 130 and devices 140 and 150. Previously, the Information Technology (IT) deployment model included enterprise resources and applications stored within an enterprise network (i.e., physical devices), behind a firewall, accessible by employees on site or remote via Virtual Private Networks (VPNs), etc. The cloud-based system 100 is replacing the conventional deployment model. The cloud-based system 100 can be used to implement these services in the cloud without requiring the physical devices and management thereof by enterprise IT administrators.
Cloud computing systems and methods abstract away physical servers, storage, networking, etc., and instead offer these as on-demand and elastic resources. The National Institute of Standards and Technology (NIST) provides a concise and specific definition which states cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. Cloud computing differs from the classic client-server model by providing applications from a server that are executed and managed by a client’s web browser or the like, with no installed client version of an application required. Centralization gives cloud service providers complete control over the versions of the browser-based and other applications provided to clients, which removes the need for version upgrades or license management on individual client computing devices. The phrase “software as a service” is sometimes used to describe application programs offered through cloud computing. A common shorthand for a provided cloud computing service (or even an aggregation of all existing cloud services) is “the cloud.” The cloud-based system 100 is illustrated herein as one example embodiment of a cloud-based system, and those of ordinary skill in the art will recognize the systems and methods described herein are not necessarily limited thereby.
The processor 202 is a hardware device for executing software instructions. The processor 202 may be any custom made or commercially available processor, a central processing unit (CPU), an auxiliary processor among several processors associated with the server 200, a semiconductor-based microprocessor (in the form of a microchip or chipset), or generally any device for executing software instructions. When the server 200 is in operation, the processor 202 is configured to execute software stored within the memory 210, to communicate data to and from the memory 210, and to generally control operations of the server 200 pursuant to the software instructions. The I/O interfaces 204 may be used to receive user input from and/or for providing system output to one or more devices or components.
The network interface 206 may be used to enable the server 200 to communicate on a network, such as the Internet 104 (
The memory 210 may include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, etc.)), nonvolatile memory elements (e.g., ROM, hard drive, tape, CDROM, etc.), and combinations thereof. Moreover, the memory 210 may incorporate electronic, magnetic, optical, and/or other types of storage media. Note that the memory 210 may have a distributed architecture, where various components are situated remotely from one another but can be accessed by the processor 202. The software in memory 210 may include one or more software programs, each of which includes an ordered listing of executable instructions for implementing logical functions. The software in the memory 210 includes a suitable operating system (O/S) 214 and one or more programs 216. The operating system 214 essentially controls the execution of other computer programs, such as the one or more programs 216, and provides scheduling, input-output control, file and data management, memory management, and communication control and related services. The one or more programs 216 may be configured to implement the various processes, algorithms, methods, techniques, etc. described herein.
It will be appreciated that some embodiments described herein may include one or more generic or specialized processors (“one or more processors”) such as microprocessors; central processing units (CPUs); digital signal processors (DSPs); customized processors such as network processors (NPs) or network processing units (NPUs), graphics processing units (GPUs), or the like; field programmable gate arrays (FPGAs); and the like along with unique stored program instructions (including both software and firmware) for control thereof to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of the methods and/or systems described herein. Alternatively, some or all functions may be implemented by a state machine that has no stored program instructions, or in one or more application-specific integrated circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic or circuitry. Of course, a combination of the aforementioned approaches may be used. For some of the embodiments described herein, a corresponding device in hardware and optionally with software, firmware, and a combination thereof can be referred to as “circuitry configured or adapted to,” “logic configured or adapted to,” etc. perform a set of operations, steps, methods, processes, algorithms, functions, techniques, etc. on digital and/or analog signals as described herein for the various embodiments.
Moreover, some embodiments may include a non-transitory computer-readable medium having computer-readable code stored thereon for programming a computer, server, appliance, device, processor, circuit, etc. each of which may include a processor to perform functions as described and claimed herein. Examples of such computer-readable mediums include, but are not limited to, a hard disk, an optical storage device, a magnetic storage device, a Read-Only Memory (ROM), a Programmable Read-Only Memory (PROM), an Erasable Programmable Read-Only Memory (EPROM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), flash memory, and the like. When stored in the non-transitory computer-readable medium, software can include instructions executable by a processor or device (e.g., any type of programmable circuitry or logic) that, in response to such execution, cause a processor or the device to perform a set of operations, steps, methods, processes, algorithms, functions, techniques, etc. as described herein for the various embodiments.
The processor 302 is a hardware device for executing software instructions. The processor 302 can be any custom made or commercially available processor, a CPU, an auxiliary processor among several processors associated with the user device 300, a semiconductor-based microprocessor (in the form of a microchip or chipset), or generally any device for executing software instructions. When the user device 300 is in operation, the processor 302 is configured to execute software stored within the memory 310, to communicate data to and from the memory 310, and to generally control operations of the user device 300 pursuant to the software instructions. In an embodiment, the processor 302 may include a mobile optimized processor such as optimized for power consumption and mobile applications. The I/O interfaces 304 can be used to receive user input from and/or for providing system output. User input can be provided via, for example, a keypad, a touch screen, a scroll ball, a scroll bar, buttons, a barcode scanner, and the like. System output can be provided via a display device such as a liquid crystal display (LCD), touch screen, and the like.
The radio 306 enables wireless communication to an external access device or network. Any number of suitable wireless data communication protocols, techniques, or methodologies can be supported by the radio 306, including any protocols for wireless communication. The data store 308 may be used to store data. The data store 308 may include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, and the like)), nonvolatile memory elements (e.g., ROM, hard drive, tape, CDROM, and the like), and combinations thereof. Moreover, the data store 308 may incorporate electronic, magnetic, optical, and/or other types of storage media.
Again, the memory 310 may include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, etc.)), nonvolatile memory elements (e.g., ROM, hard drive, etc.), and combinations thereof. Moreover, the memory 310 may incorporate electronic, magnetic, optical, and/or other types of storage media. Note that the memory 310 may have a distributed architecture, where various components are situated remotely from one another, but can be accessed by the processor 302. The software in memory 310 can include one or more software programs, each of which includes an ordered listing of executable instructions for implementing logical functions. In the example of
Although the present disclosure is illustrated and described herein with reference to illustrative embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present disclosure, are contemplated thereby, and are intended to be covered by the following non-limiting claims for all purposes.
The present disclosure claims the benefit of priority of co-pending U.S. Provisional Pat. Application No. 63/280,168, filed on Nov. 17, 2021, and entitled “DEFORMABLE RADAR POLYGON SYSTEMS AND METHODS FOR A VIRTUAL BUMPER,” the contents of which are incorporated in full by reference herein.
Number | Date | Country | |
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63280168 | Nov 2021 | US |