Systems of interacting objects often evolve under the influence of underlying field effects that govern their dynamics, yet previous works have abstracted away from such effects, and assume that systems evolve in a vacuum. In this work, we focus on discovering these fields, and infer them from the observed dynamics alone, without directly observing them. We theorize the presence of latent force fields, and propose neural fields to learn them. Since the observed dynamics constitute the net effect of local object interactions and global field effects, recently popularized equivariant networks are inapplicable, as they fail to capture global information. To address this, we propose to disentangle local object interactions --which are SE(3) equivariant and depend on relative states-- from external global field effects --which depend on absolute states. We model the interactions with equivariant graph networks, and combine them with neural fields in a novel graph network that integrates field forces. Our experiments show that we can accurately discover the underlying fields in charged particles settings, traffic scenes, and gravitational n-body problems, and effectively use them to learn the system and forecast future trajectories.

Semantic segmentation is one of the popular tasks in computer vision, providing pixel-wise annotations for scene understanding. However, segmentation-based convolutional neural networks require tremendous computational power. In this work, a fully-pipelined hardware accelerator with support for dilated convolution is introduced, which cuts down the redundant zero multiplications. Furthermore, we propose a genetic algorithm based automated channel pruning technique to jointly optimize computational complexity and model accuracy. Finally, hardware heuristics and an accurate model of the custom accelerator design enable a hardware-aware pruning framework. We achieve 2.44X lower latency with minimal degradation in semantic prediction quality (−1.98 pp lower mean intersection over union) compared to the baseline DeepLabV3+ model, evaluated on an Arria-10 FPGA. The binary files of the FPGA design, baseline and pruned models can be found in github.com/pierpaolomori/SemanticSegmentationFPGA

We present AnaCoNGA, an analytical co-design methodology, which enables two genetic algorithms to evaluate the fitness of design decisions on layer-wise quantization of a neural network and hardware (HW) resource allocation. We embed a hardware architecture search (HAS) algorithm into a quantization strategy search (QSS) algorithm to evaluate the hardware design Pareto-front of each considered quantization strategy. We harness the speed and flexibility of analytical HW-modeling to enable parallel HW-CNN co-design. With this approach, the QSS is focused on seeking high-accuracy quantization strategies which are guaranteed to have efficient hardware designs at the end of the search. Through AnaCoNGA, we improve the accuracy by 2.88 p.p. with respect to a uniform 2-bit ResNet20 on CIFAR-10, and achieve a 35% and 37% improvement in latency and DRAM accesses, while reducing LUT and BRAM resources by 9% and 59% respectively, when compared to a standard edge variant of the accelerator. The nested genetic algorithm formulation also reduces the search time by 51% compared to an equivalent, sequential co-design formulation.

Predicting future events accurately is a task of great importance for autonomous vehicles. In this work we focus on lane change events. For this, we propose a novel attention mechanism on top of recurrent neural networks for the prediction task, which improves performance and yields more interpretable models. As critical corner cases are often not considered and reflected in traditional prediction metrics, we additionally introduce a new scenario-based evaluation scheme, which we posit be considered for further maneuver prediction works. Prediction and planning tasks often are correlated, usually sharing input representations and differing in expected outputs and their subsequent consideration. Here, we detail a supporting layer for planning tasks, which analyzes situations w.r.t. their suitability for lane changes and can serve as decision-making support for any planning algorithm. Exploitation of similarities between this task and the aforementioned prediction problem further improves performance of the prediction task, as well as labelling quality of the assessment task. Additionally, we extend our evaluation to urban scenarios, showcasing the generalizability of our proposed prediction models.

Intelligent, semi-autonomous prostheses take ad-vantage of combining autonomous functions and traditional myoelectric control. With the help of visual and environment sensors, intelligent prostheses achieve a level of autonomy which relieves the user from generating elaborate electromyographic (EMG) signals for grasp type and trajectory. To achieve the desired functionality, the semi-autonomous prosthesis must efficiently process the incoming environmental data at a high rate, with low power and high accuracy. In this paper, we propose Binary-LoRAX, a low-latency runtime adaptable classifier for the semi-autonomous grasping task of prosthetic hands. We offload the classification task to an efficient binary neural network accelerator which performs high-throughput XNOR operations on digital signal processing (DSP) blocks. To tailor the classifier’s performance to the current application scenario, we propose a frequency scaling approach which dynamically switches between two modes of operation, high-performance and power-saving. At high-performance, classifications are performed with a low latency of 0.45ms, high-throughput of 4999 FPS and power consumption of ∼ 2.15 W. This enables functions such as object localization and batch classification. Switching to power-saving mode, a latency of 80 ms is maintained, with up to 19% improved classifier battery-life. Our prototypes achieve a high accuracy of up to 99.82% on a 25 class problem from the YCB graspable object dataset.

Traffic sign detection is crucial for enabling autonomous vehicles to navigate in real-world streets, which must be carried out with high accuracy and in real-time. CNNs have become one of the standard approaches for traffic sign detection research in recent years. The use of CNNs has allowed the development of traffic sign detectors that are capable of achieving prediction accuracies similar to those of human drivers. However, most CNNs do not run in real-time due to the high number of computational operations involved during the inference phase. This hinders the deployment of CNNs in autonomous vehicles despite their high prediction accuracy. In this paper, we explore BNNs to tackle this problem. BNNs binarize the full-precision weights and activations of a CNN, drastically reducing the complexity of the computational operations required for inference, while at the same time maintaining the architectural parameters, as well as spatial dimensions of the input image. This reduces the memory required to run the model and enables faster inference time. We carry out in-depth studies on applying BNNs for traffic sign detection using real-world datasets. We observe an improvement of 11.63 × for normalized compute complexity, while suffering only 3.93 pp in detection accuracy on GTSDB dataset.

Modelling interactions is critical in learning complex dynamical systems, namely systems of interacting objects with highly non-linear and time-dependent behaviour. A large class of such systems can be formalized as $\textit{geometric graphs}$, $\textit{i.e.}$ graphs with nodes positioned in the Euclidean space given an $\textit{arbitrarily}$ chosen global coordinate system, for instance vehicles in a traffic scene. Notwithstanding the arbitrary global coordinate system, the governing dynamics of the respective dynamical systems are invariant to rotations and translations, also known as $\textit{Galilean invariance}$. As ignoring these invariances leads to worse generalization, in this work we propose local coordinate systems per node-object to induce roto-translation invariance to the geometric graph of the interacting dynamical system. Further, the local coordinate systems allow for a natural definition of anisotropic filtering in graph neural networks. Experiments in traffic scenes, 3D motion capture, and colliding particles demonstrate the proposed approach comfortably outperforms the recent state-of-the-art.

Model compression through quantization is commonly applied to convolutional neural networks (CNNs) deployed on compute and memory-constrained embedded platforms. Different layers of the CNN can have varying degrees of numerical precision for both weights and activations, resulting in a large search space. Together with the hardware (HW) design space, the challenge of finding the globally optimal HW-CNN combination for a given application becomes daunting. To this end, we propose HW-FlowQ, a systematic approach that enables the co-design of the target hardware platform and the compressed CNN model through quantization. The search space is viewed at three levels of abstraction, allowing for an iterative approach for narrowing down the solution space before reaching a high-fidelity CNN hardware modeling tool, capable of capturing the effects of mixed-precision quantization strategies on different hardware architectures (processing unit counts, memory levels, cost models, dataflows) and two types of computation engines (bit-parallel vectorized, bit-serial). To combine both worlds, a multi-objective non-dominated sorting genetic algorithm (NSGA-II) is leveraged to establish a Pareto-optimal set of quantization strategies for the target HW-metrics at each abstraction level. HW-FlowQ detects optima in a discrete search space and maximizes the task-related accuracy of the underlying CNN while minimizing hardware-related costs. The Pareto-front approach keeps the design space open to a range of non-dominated solutions before refining the design to a more detailed level of abstraction. With equivalent prediction accuracy, we improve the energy and latency by 20% and 45% respectively for ResNet56 compared to existing mixed-precision search methods.

Closing the gap between the hardware requirements of state-of-the-art convolutional neural networks and the limited resources constraining embedded applications is the next big challenge in deep learning research. The computational complexity and memory footprint of such neural networks are typically daunting for deployment in resource constrained environments. Model compression techniques, such as pruning, are emphasized among other optimization methods for solving this problem. Most existing techniques require domain expertise or result in irregular sparse representations, which increase the burden of deploying deep learning applications on embedded hardware accelerators. In this paper, we propose the autoencoder-based low-rank filter-sharing technique (ALF). When applied to various networks, ALF is compared to state-of-the-art pruning methods, demonstrating its efficient compression capabilities on theoretical metrics as well as on an accurate, deterministic hardware-model. In our experiments, ALF showed a reduction of 70% in network parameters, 61% in operations and 41% in execution time, with minimal loss in accuracy.

Driveable area detection is a key component for various applications in the field of autonomous driving (AD), such as ground-plane detection, obstacle detection and maneuver planning. Additionally, bulky and over-parameterized networks can be easily forgone and replaced with smaller networks for faster inference on embedded systems. The driveable area detection, posed as a two class segmentation task, can be efficiently modeled with slim binary networks. This paper proposes a novel binarized driveable area detection network (binary DAD-Net), which uses only binary weights and activations in the encoder, the bottleneck, and the decoder part. The latent space of the bottleneck is efficiently increased (×32→×16 downsampling) through binary dilated convolutions, learning more complex features. Along with automatically generated training data, the binary DAD-Net outperforms state-of-the-art semantic segmentation networks on public datasets. In comparison to a full-precision model, our approach has a ×14.3 reduced compute complexity on an FPGA and it requires only 0.9MB memory resources. Therefore, commodity SIMD-based AD-hardware is capable of accelerating the binary DAD-Net.

As the use of videos is becoming more popular in computer vision, the need for annotated video datasets increases. Such datasets are required either as training data or simply as ground truth for benchmark datasets. A particular challenge in video segmentation is due to disocclusions, which hamper frame-to-frame propagation, in conjunction with non-moving objects. We show that a combination of motion from point trajectories, as known from motion segmentation, along with minimal supervision can largely help solve this problem. Moreover, we integrate a new constraint that enforces consistency of the color distribution in successive frames. We quantify user interaction effort with respect to segmentation quality on challenging ego motion videos. We compare our approach to a diverse set of algorithms in terms of user effort and in terms of performance on common video segmentation benchmarks.

Video segmentation research is currently limited by the lack of a benchmark dataset that covers the large variety of sub problems appearing in video segmentation and that is large enough to avoid over fitting. Consequently, there is little analysis of video segmentation which generalizes across subtasks, and it is not yet clear which and how video segmentation should leverage the information from the still-frames, as previously studied in image segmentation, alongside video specific information, such as temporal volume, motion and occlusion. In this work we provide such an analysis based on annotations of a large video dataset, where each video is manually segmented by multiple persons. Moreover, we introduce a new volume-based metric that includes the important aspect of temporal consistency, that can deal with segmentation hierarchies, and that reflects the tradeoff between over-segmentation and segmentation accuracy.