Selection of Radiomics Features based on their Reproducibility

Dimensionality reduction is key to alleviate machine learning artifacts in clinical applications with Small Sample Size (SSS) unbalanced datasets. Existing methods rely on either the probabilistic distribution of training data or the discriminant power of the reduced space, disregarding the impact of repeatability and uncertainty in features.In the present study is proposed the use of reproducibility of radiomics features to select features with high inter-class correlation coefficient (ICC). The reproducibility includes the variability introduced in the image acquisition, like medical scans acquisition parameters and convolution kernels, that affects intensity-based features and tumor annotations made by physicians, that influences morphological descriptors of the lesion.For the reproducibility of radiomics features three studies were conducted on cases collected at Vall Hebron Oncology Institute (VHIO) on responders to oncology treatment. The studies focused on the variability due to the convolution kernel, image acquisition parameters, and the inter-observer lesion identification. The features selected were those features with a ICC higher than 0.7 in the three studies.The selected features based on reproducibility were evaluated for lesion malignancy classification using a different database. Results show better performance compared to several state-of-the-art methods including Principal Component Analysis (PCA), Kernel Discriminant Analysis via QR decomposition (KDAQR), LASSO, and an own built Convolutional Neural Network

Detección de fatiga al volante

Aquest document conté originàriament altre material i/o programari només consultable a la Biblioteca de Ciència i Tecnologia

Detección de fatiga al volante

Aquest document conté originàriament altre material i/o programari només consultable a la Biblioteca de Ciència i Tecnologia

A computer vision approach to monitor activity in commercial broiler chickens using trajectory-based clustering analysis

To monitor changes in broiler behaviour related to animal health and welfare, farmers typically observe their flocks using manual observation. However, due to the labour intensive and continuous aspect of this task, the analysis of broiler behaviour could be automated using camera technology. This paper proposes a proof-of-concept camera surveillance system based on the automated detection and tracking of broilers to monitor activity bouts using unsupervised 2D trajectory clustering. Firstly, a convolutional neural network-based detector was trained and tested on our labelled dataset which resulted in a precision, recall and f score of 0.98, 0.90 and 0.94, respectively. Using a tracking-by-detection approach, the proposed system was able to track chickens across video frames with a multi-object tracking accuracy of 74.7%. A component-based feature saliency Gaussian mixture model (CFSGMM) was subsequently generated and applied to objectively cluster the trajectories based on their spatiotemporal information. Nineteen features were extracted from the trajectories, representing both static and dynamic characteristics of broiler movement, and three activity classes were identified: ‘least active/resting,’ ‘active’ and ‘highly-active.’ The proposed method was validated on one-minute monocular video sequences. CFSGMM was applied to cluster 2D trajectories relating to broiler activity bouts within the commercial rearing environment with an agreement ranging from 6.0 to 99.7% when compared to human observation. We demonstrate the potential of the computer vision system to monitor overt, short-term changes in broiler activity associated with on-farm events and discuss the opportunities of leveraging the technology to monitor longer term changes in welfare state. It is anticipated that further development of the detection and tracking systems will improve the performance of the trajectory clustering method