Nowadays, Deep Neural Networks are considered to be one of the most powerful tools for solving many AI problems. In particular, Convolutional Neural Networks (CNN) are able to achieve state-of-the art results in image processing problems such as classification, detection, image restoration and enhancement, to name a few.
Dense 3D pose estimation from 2D images is a promising new feature for mobile devices such as modern smartphones, where it enables vast applications such as AR/VR-based navigation and entertainment systems. Recent achievements in deep learning-based computer vision (e.g. Facebook’s DensePose system, cf. http://densepose.org) indicate that CNNs are a promising framework for image-based 3D pose reconstruction. However, CNN-based solutions are very computationally and memory consuming so that inference process require both sufficient hardware resources and energy, while, at the same time, edge devices like smartphones cannot satisfy the computational demands posed by modern CNN architectures. Moreover, even the exact architecture of the computational model depends heavily on the target hardware: whether any hardware acceleration could be supported, what kind of computing and memory devices are available, and what is an input signal for a smartphone are some questions developers have to consider.
Within the scope of this project, we consider two directions of research Development of an accurate and algorithmically efficient computer vision architecture tailored specifically for the dense 3D pose estimation from 2D images on a mobile device, that has technical characteristics similar to that of a Huawei flagship device (e.g. Huawei P20). Within this direction, we plan to (1) conduct a survey into efficient neural network architectures, object detection, pose estimation, and body shape regression tasks such as [15,17,18,19], (2) develop an efficient multi-stage neural network architecture to incorporate person detection and body shape regression into a unified procedure, (3) perform additional research to test whether the overall task could be solved in a joint fashion by a single multi-output model such as .
Optimization of CNN inference running time and energy consumption Within this direction, we plan to consider two lines of approaches, identify the most promising ones, and implement those within the proposed algorithm:
Algorithmic complexity reduction of the CNN inference procedure (simplification) This includes many approaches, e.g., reducing the number of model parameters, inducing sparsity to the model , pruning neurons , merging neurons, replacing some layers by light-weight analogues , and low-rank approximation of the model parameters [4, 5]. Less amount of computations will likely result in reduced energy consumption and running times.
Hardware support and low-level engineering to perform more computations using same power within the same time period The most popular approach lays in moving CNN inference process towards using low-precision arithmetic (i.e. quantizing the 32-bit floating-point based weights of the neural network into 16bit, 8bit, or even 1bit precision, cf. [6, 7]). This approach, so called quantization, allows either to use SIMD instructions supported by most of existing hardware or develop new specific hardware for low-precision arithmetic. In the first case we can expect significant acceleration of running time, while in the second case we can benefit much in energy consumption.
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