Evaluation of Colour Pre-processing on Patch-Based Classification of H&E-Stained Images

This paper compares the effects of colour pre-processing on the classification performance of H&E-stained images. Variations in the tissue preparation procedures, acquisition systems, stain conditions and reagents are all source of artifacts that can affect negatively computer-based classification. Pre-processing methods such as colour constancy, transfer and deconvolution have been proposed to compensate the artifacts. In this paper we compare quantitatively the combined effect of six colour pre-processing procedures and 12 colour texture descriptors on patch-based classification of H&E-stained images. We found that colour pre-processing had negative effects on accuracy in most cases – particularly when used with colour descriptors. However, some pre-processing procedures proved beneficial when employed in conjunction with classic texture descriptors such as co-occurrence matrices, Gabor filters and Local Binary Patterns

Automated Low-Cost Malaria Detection System in Thin Blood Slide Images Using Mobile Phones

Malaria, a deadly disease which according to the World Health Organisation (WHO) is responsible for the fatal illness in 200 million people around the world in 2010, is diagnosed using peripheral blood examination. The work undertaken in this research programme aims to develop an automated malaria parasite-detection system, using microscopic-image processing, that can be incorporated onto mobile phones. In this research study, the main objective is to achieve the performance equal to or better than the manual microscopy, which is the gold standard in malaria diagnosis, in order to produce a reliable automated diagnostic platform without expert intervention, for the effective treatment and eradication of the deadly disease. The work contributed to the field of mathematical morphology by proposing a novel method called the Annular Ring Ratio transform for blood component identification. It has also proposed an automated White Blood Cell and Red Blood Cell differentiation algorithm, which when combined with ARR transform method, has wide applications not only for malaria diagnosis but also for many blood related analysis involving microscopic examination. The research has undertaken investigations on infected cell identification which aids in the calculation of parasitemia, the measure of infection. In addition, an automated diagnostic tool to detect the sexual stage (gametocytes) of the species P.falciparum for post-treatment malaria diagnosis was developed. Furthermore, a parallel investigation was carried out on automated malaria diagnosis on fluorescent thin blood films and a WBC and infected cell differentiation algorithm was proposed. Finally, a mobile phone application based on the morphological image processing algorithms proposed in this thesis was developed. A complete malaria diagnostic unit using the mobile phones attached to a portable microscope was set up which has enormous potential not only for malaria diagnosis but also for the blood parasitological field where advancement in medical diagnostics using cellular smart phone technology is widely acknowledged

Applications of Deep Learning in Medical Image Analysis : Grading of Prostate Cancer and Detection of Coronary Artery Disease

A wide range of medical examinations are using analysis of images from different types of equipment. Using artificial intelligence, the assessments could be done automatically. This can have multiple benefits for the healthcare; reduce workload for medical doctors, decrease variations in diagnoses and cut waiting times for the patient as well as improve the performance. The aim of this thesis has been to develop such solutions for two common diseases: prostate cancer and coronary artery disease. The methods used are mainly based on deep learning, where the model teaches itself by training on large datasets.Prostate cancer is one of the most common cancer diagnoses among men. The diagnosis is most commonly determined by visual assessment of prostate biopsies in a light microscope according to the Gleason scale. Deep learning methods to automatically detect and grade the cancer areas are presented in this thesis. The methods have been adapted to improve the generalisation performance on images from different hospitals, images which have inevitable variations in e.g.\ stain appearance. The methods include the usage of digital stain normalisation, training with extensive augmentation or using models such as a domain-adversarial neural network. One Gleason grading algorithm was evaluated on a small cohort with biopsies annotated in detail by two pathologists, to compare the performance with pathologists' inter-observer variability. Another cancer detection algorithm was evaluated on a large active surveillance cohort, containing patients with small areas of low-grade cancer. The results are promising towards a future tool to facilitate grading of prostate cancer.Cardiovascular disease is the leading cause of death world-wide, whereof coronary artery disease is one of the most common diseases. One way to diagnose coronary artery disease is by using myocardial perfusion imaging, where disease in the three main arteries supplying the heart with blood can be detected. Methods based on deep learning to perform the detection automatically are presented in this thesis. Furthermore, an algorithm developed to predict the degree of coronary artery stenosis from myocardial perfusion imaging, by means of quantitative coronary angiography, has also been developed. This assessment is normally done using invasive coronary angiography. Making the prediction automatically from myocardial perfusion imaging could save suffering for patients and free resources within the healthcare system