Dominic Ward

Alistair Mackenzie, Mark Halling-Brown, Ruben van Engen et al.

In this report a framework for the collection of clinical images and data for use when training and validating artificial intelligence (AI) tools is described. The report contains not only information about the collection of the images and clinical data, but the ethics and information governance processes to consider ensuring the data is collected safely, and the infrastructure and agreements required to allow for the sharing of data with other groups. A key characteristic of the main collection framework described here is that it can enable automated and ongoing collection of datasets to ensure that the data is up-to-date and representative of current practice. This is important in the context of training and validating AI tools as it is vital that datasets have a mix of older cases with long term follow-up such that the clinical outcome is as accurate as possible, and current data. Validations run on old data will provide findings and conclusions relative to the status of the imaging units when that data was generated. It is important that a validation dataset can assess the AI tools with data that it would see if deployed and active now. Other types of collection frameworks, which do not follow a fully automated approach, are also described. Whilst the fully automated method is recommended for large scale, long-term image collection, there may be reasons to start data collection using semi-automated methods and indications of how to do that are provided.

Emad M. Grais, Hagen Wierstorf, Dominic Ward et al.

Current performance evaluation for audio source separation depends on comparing the processed or separated signals with reference signals. Therefore, common performance evaluation toolkits are not applicable to real-world situations where the ground truth audio is unavailable. In this paper, we propose a performance evaluation technique that does not require reference signals in order to assess separation quality. The proposed technique uses a deep neural network (DNN) to map the processed audio into its quality score. Our experiment results show that the DNN is capable of predicting the sources-to-artifacts ratio from the blind source separation evaluation toolkit without the need for reference signals.

Emad M. Grais, Dominic Ward, Mark D. Plumbley

Supervised multi-channel audio source separation requires extracting useful spectral, temporal, and spatial features from the mixed signals. The success of many existing systems is therefore largely dependent on the choice of features used for training. In this work, we introduce a novel multi-channel, multi-resolution convolutional auto-encoder neural network that works on raw time-domain signals to determine appropriate multi-resolution features for separating the singing-voice from stereo music. Our experimental results show that the proposed method can achieve multi-channel audio source separation without the need for hand-crafted features or any pre- or post-processing.

Emad M. Grais, Hagen Wierstorf, Dominic Ward et al.

In deep neural networks with convolutional layers, each layer typically has fixed-size/single-resolution receptive field (RF). Convolutional layers with a large RF capture global information from the input features, while layers with small RF size capture local details with high resolution from the input features. In this work, we introduce novel deep multi-resolution fully convolutional neural networks (MR-FCNN), where each layer has different RF sizes to extract multi-resolution features that capture the global and local details information from its input features. The proposed MR-FCNN is applied to separate a target audio source from a mixture of many audio sources. Experimental results show that using MR-FCNN improves the performance compared to feedforward deep neural networks (DNNs) and single resolution deep fully convolutional neural networks (FCNNs) on the audio source separation problem.