A. G. Jones

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Existing Shape from Shading algorithms are not robust enough to work reliably with real images. We present a new paradigm for Shape from Shading based upon & scale space surface representation. Using this representation, the Shape from Shading problem becomes one of forming a surface from gaussian basis functions in such a way that the shading in the(More)
C-peptide is produced in equal amounts to insulin and is the best measure of endogenous insulin secretion in patients with diabetes. Measurement of insulin secretion using C-peptide can be helpful in clinical practice: differences in insulin secretion are fundamental to the different treatment requirements of Type 1 and Type 2 diabetes. This article reviews(More)
OBJECTIVE Stimulated serum C-peptide (sCP) during a mixed-meal tolerance test (MMTT) is the gold standard measure of endogenous insulin secretion, but practical issues limit its use. We assessed urine C-peptide creatinine ratio (UCPCR) as an alternative. RESEARCH DESIGN AND METHODS Seventy-two type 1 diabetic patients (age of diagnosis median 14 years(More)
Ill-posed inverse problems are widely encountered in computer vision. examples include shape from shading, surface reconstruction from sparse data and optic flow. Unique solutions to these problems are conventionally found by minimizing an objective function regularized by a smoothness constraint. However, objective functions of this form often contain many(More)
AIMS/HYPOTHESIS Classically, type 1 diabetes is thought to proceed to absolute insulin deficiency. Recently developed ultrasensitive assays capable of detecting C-peptide under 5 pmol/l now allow very low levels of C-peptide to be detected in patients with long-standing type 1 diabetes. It is not known whether this low-level endogenous insulin secretion(More)
Shape-from-shading algorithms that use a single image often find incorrect solutions because of ambiguity in the image shading. We describe a robust shape-from-shading algorithm using scale space tracking that can resolve most of these ambiguities by using two images taken from slightly different positions. Further improvements are obtained by combining(More)
BACKGROUND In patients with both Type 1 and Type 2 diabetes endogenous insulin secretion falls with time which changes treatment requirements, however direct measurement of endogenous insulin secretion is rarely performed. We aimed to assess the impact of endogenous insulin secretion on postprandial glucose increase and the effectiveness of prandial(More)
OBJECTIVE Clinicians predominantly use clinical features to differentiate type 1 from type 2 diabetes yet there are no evidence-based clinical criteria to aid classification of patients. Misclassification of diabetes is widespread (7-15% of cases), resulting in patients receiving inappropriate treatment. We sought to identify which clinical criteria could(More)
AIMS To determine the prevalence and clinical characteristics of absolute insulin deficiency in long-standing Type 2 diabetes, using a strategy based on home urinary C-peptide creatinine ratio measurement. METHODS We assessed the urinary C-peptide creatinine ratios, from urine samples taken at home 2 h after the largest meal of the day, in 191(More)
AIMS Baseline HbA1c is a major predictor of response to glucose lowering therapy and therefore a potential confounder in studies aiming to identify other predictors. However, baseline adjustment may introduce error if the association between baseline HbA1c and response is substantially due to measurement error and regression to the mean. We aimed to(More)