Abstract: This document describes techniques and systems for stationary object detection and classification based on low-level radar data. Raw electromagnetic signals reflected off stationary objects and received by a radar system may be preprocessed to produce low-level spectrum data in the form of range-Doppler maps that retain all or nearly all the data present in the raw electromagnetic signals. The preprocessing may also filter non-stationary range-Doppler bins. The remaining low-level spectrum data represents stationary objects present in a field-of-view (FOV) of the radar system. The low-level spectrum data representing stationary objects can be fed to an end-to-end deep convolutional detection and classification network that is trained to classify and provide object bounding boxes for the stationary objects. The outputted classifications and bounding boxes related to the stationary objects may be provided to other driving systems to improve their functionality resulting in a safer driving experience.

Abstract: This document describes systems and techniques related to deep association for sensor fusion. For example, a model trained using deep machine learning techniques, may be used to generate an association score matrix that includes probabilities that tracks from different types of sensors are related to the same objects. This model may be trained using a convolutional recurrent neural network and include constraints not included in other training techniques. Focal loss can be used during training to compensate for imbalanced data samples and address difficult cases, and data expansion techniques can be used to increase the multi-sensor data space. Simple thresholding techniques can be applied to the association score matrix to generate an assignment matrix that indicates whether tracks from one sensor and tracks from another sensor match. In this manner, the track association process may be more accurate than current sensor fusion techniques, and vehicle safety may be increased.

Abstract: Techniques and apparatuses are described that implement height-estimation of objects using radar. In particular, a radar system, which is mounted to a moving platform, receives reflection signals that represent versions of a radar signal that are reflected off of objects. The radar system generates a range-elevation map based on raw data from the reflection signals, identifies an elevation bin and a range bin in the range-elevation map that corresponds to a selected object, and calculates a height for the selected object based on the range and elevation bins. The radar system then calculates a de-noised height for the selected object based on one or more previously calculated heights for the selected object. In this way, the radar system can determine accurate heights of objects at sufficiently long ranges for evasive action.

Abstract: This document describes techniques and systems for fuzzy labeling of low-level electromagnetic sensor data. Sensor data in the form of an energy spectrum is obtained and the points within an estimated geographic boundary of a scatterer represented by the smear is labeled with a value of one. The remaining points of the energy spectrum are labeled with values between zero and one with the values decreasing the further away each respective remaining point is from the geographic boundary. The fuzzy labeling process may harness more in-depth information available from the distribution of the energy in the energy spectrum. A model can be trained to efficiently label an energy spectrum map in this manner. This may result in lower computational costs than other labeling methods. Additionally, false detections by the sensor may be reduced resulting in more accurate detection and tracking of objects.

Abstract: This document describes systems and techniques for determining a height of an object in a surrounding of a vehicle. In a first aspect, the systems and techniques include acquiring radar data for each of a plurality of vertically distributed antenna elements of a radar antenna. In additional aspects, the systems and techniques include estimating an elevation spectrum from the acquired radar data, extracting one or more features representative of the shape of the estimated elevation spectrum, and determining the height of the object using the extracted one or more features.

Abstract: This document describes techniques and systems for machine-learning-based super resolution of radar data. A low-resolution radar image can be used as input to train a model for super resolution of radar data. A higher-resolution radar image, generated by an effective, but costly in terms of computing resources, traditional super resolution method, and the higher-resolution image can serve as ground truth for training the model. The resulting trained model may generate a high-resolution sensor image that closely approximates the image generated by the traditional method. Because this trained model needs only to be executed in feed-forward mode in the inference stage, it may be suited for real-time applications. Additionally, if low-level radar data is used as input for training the model, the model may be trained with more comprehensive information than can be obtained in detection level radar data.

Abstract: This document describes techniques and systems for improving accuracy of predictions on radar data using vehicle-to-vehicle (V2V) technology. V2V communications data and the matching sensor data related to one or more vehicles in the vicinity of a host vehicle are collected. The V2V data is used as label data and the radar data is used as the input data for training the model. The training may either occur onboard the host vehicle or remotely. Further, multiple host vehicles may contribute data to train the model. Once the model has been updated with the included training, the updated model is deployed to the sensor tracking system of the host vehicle. By using the dataset that includes the V2V communications data and the matching sensor data, the updated model may accurately track other vehicles and enable the host vehicle to utilize advanced driver-assistance systems safely and reliably.

Abstract: This document describes techniques and systems related to a radar system using a machine-learned model for stationary object detection. The radar system includes a processor that can receive radar data as time-series frames associated with electromagnetic (EM) energy. The processor uses the radar data to generate a range-time map of the EM energy that is input to a machine-learned model. The machine-learned model can receive as inputs extracted features corresponding to the stationary objects from the range-time map for multiple range bins at each of the time-series frames. In this way, the described radar system and techniques can accurately detect stationary objects of various sizes and extract critical features corresponding to the stationary objects.

Abstract: This document describes techniques, apparatuses, and systems for sensor fusion for object-avoidance detection, including stationary-object height estimation. A sensor fusion system may include a two-stage pipeline. In the first stage, time-series radar data passes through a detection model to produce radar range detections. In the second stage, based on the radar range detections and camera detections, an estimation model detects an over-drivable condition associated with stationary objects in a travel path of a vehicle. By projecting radar range detections onto pixels of an image, a histogram tracker can be used to discern pixel-based dimensions of stationary objects and track them across frames. With depth information, a highly accurate pixel-based width and height estimation can be made, which after applying over-drivability thresholds to these estimations, a vehicle can quickly and safely make over-drivability decisions about objects in a road.

Abstract: Techniques and apparatuses are described that implement height-estimation of objects using radar. In particular, a radar system, which is mounted to a moving platform, receives reflection signals that represent versions of a radar signal that are reflected off of objects. The radar system generates a range-elevation map based on raw data from the reflection signals, identifies an elevation bin and a range bin in the range-elevation map that corresponds to a selected object, and calculates a height for the selected object based on the range and elevation bins. The radar system then calculates a de-noised height for the selected object based on one or more previously calculated heights for the selected object. In this way, the radar system can determine accurate heights of objects at sufficiently long ranges for evasive action.

Abstract: A caries detection system and method for quantifying a probability of lesions existing in tissues are presented. Digital X-ray images are segmented and further processed to generate feature statistics inputs for a neural network. The feature statistics include colinearity measurements of candidate lesions in different tissue segments. The neural network is trained by back propagation with an extensive data set of radiographs and histologic examinations and processes the statistics to determine the probability of lesions existing in the tissues.

Abstract: A data processing system and method for solving pattern classification problems and function-fitting problems includes a neural network in which N-dimensional input vectors are augmented with at least one element to form an N+j-dimensional projected input vector, whose magnitude is then preferably normalized to lie on the surface of a hypersphere. Weight vectors of at least a lowest intermediate layer of network nodes are preferably also constrained to lie on the N+j-dimensional surface.To train the network, the system compares network output values with known goal vectors, and an error function (which depends on all weights and threshold values of the intermediate and output nodes) is then minimized. In order to decrease the network's learning time even further, the weight vectors for the intermediate nodes are initially preferably set equal to known prototypes for the various classes of input vectors.