Out-of-focus Blur: Image De-blurring

Image de-blurring is important in many cases of imaging a real scene or object by a camera. This project focuses on de-blurring an image distorted by an out-of-focus blur through a simulation study. A pseudo-inverse filter is first explored but it fails because of severe noise amplification. Then Tikhonov regularization methods are employed, which produce greatly improved results compared to the pseudo-inverse filter. In Tikhonov regularization, the choice of the regularization parameter plays a critical rule in obtaining a high-quality image, and the regularized solutions possess a semi-convergence property. The best result, with the relative restoration error of 8.49%, is achieved when the prescribed discrepancy principle is used to decide an optimal value. Furthermore, an iterative method, Conjugated Gradient, is employed for image de-blurring, which is fast in computation and leads to an even better result with the relative restoration error of 8.22%. The number of iteration in CG acts as a regularization parameter, and the iterates have a semi-convergence property as well.Comment: 11 page

Odds-ratio for abdominal obesity according to the educational level, for adults and old adults.

<p>Odds-ratio for abdominal obesity according to the educational level, for adults and old adults.</p

Descriptive characteristics.

<p>Abbreviations: BMI, body mass index; WC, waist circumference.</p>a<p>Significant differences between gender (p<0.05).</p

Prevalence of overweight and obesity in Portuguese adult population.

<p>Data from the current study, adjusted for national education and for the education reported in the 2003–2005 survey, and prevalence from the 2003–2005 survey in the adult population.</p

Body mass index and waist circumference and prevalence of overweight, obesity and abdominal obesity in the adult population of Portugal, by sex and age category, adjusted for educational level.

<p>Abbreviations: BMI, body mass index; WC, waist circumference.</p><p>Results presented are adjusted for the weight factor for educational level.</p>a<p>Significant differences between gender (p<0.05).</p>b<p>Significant differences between adult and older adults (p<0.05).</p

Odds-ratio for overweight and obesity according to the educational level, for adults and old adults.

<p>Odds-ratio for overweight and obesity according to the educational level, for adults and old adults.</p

Relationship of the ln transformed lower limbs lean soft tissue (LST_DXA) with chronological age (CA, panel a), percentage of predicted mature stature attained at the time of study (% PMS, panel b), and <i>z</i>-score for % PMS (<i>z</i> PMS, panel c).

<p>Relationship of the ln transformed lower limbs lean soft tissue (LST_DXA) with chronological age (CA, panel a), percentage of predicted mature stature attained at the time of study (% PMS, panel b), and <i>z</i>-score for % PMS (<i>z</i> PMS, panel c).</p

Descriptive statistics (<i>n</i> = 75) for chronological age, maturity status and body composition, and results of the Kolmogorov–Smirnov test for checking the normality of the distribution.

<p>Abbreviations: PMS, predicted mature stature; DXA, dual x-ray absorptiometry; BMD, bone mineral density; BMC, Bone mineral content.</p><p>Descriptive statistics (<i>n</i> = 75) for chronological age, maturity status and body composition, and results of the Kolmogorov–Smirnov test for checking the normality of the distribution.</p

Descriptive statistics (<i>n</i> = 75) for anthropometric variables, results of the Kolmogorov–Smirnov test for checking the normality of the distribution, and bivariate correlations of anthropometry with chronological age and maturity status.

<p>Abbreviations: CA, Chronological age; PMS, predicted mature stature; <i>r</i>, Pearson's product moment correlation coefficient; 95% CI, 95% confidence interval.</p><p>Descriptive statistics (<i>n</i> = 75) for anthropometric variables, results of the Kolmogorov–Smirnov test for checking the normality of the distribution, and bivariate correlations of anthropometry with chronological age and maturity status.</p

Reproducibility of estimated optimal peak output using a force-velocity test on a cycle ergometer

<div><p>The current study aimed to examine the reproducibility of estimated peak power and estimated pedal velocity in a multi-trial 10-s all-out cycling test among adult athletes (n = 22; aged 23.50±4.73 years). Stature, sitting height and body mass were measured. Leg length was estimated as stature minus sitting height. Body volume was obtained from air displacement plethysmography and was subsequently used to calculate body density. Fat mass and fat-free mass were derived. The short-term power outputs were assessed from the force-velocity test (FVT), using a friction-braked ergometer on two separated occasions. Differences between repeated measurements were examined with paired t-test and effect sizes calculated. No significant differences were found between session 1 (898 W, 142 rpm) and session 2 (906 W, 142 rpm). Test-retest procedure showed acceptable reliability for estimated peak power output [technical error of measurement (TEM) = 31.9 W; % coefficient of variation (CV) = 3.5; intra-class correlation coefficient (ICC) = 0.986] and pedal velocity (TEM = 5.4 rpm, %CV = 3.8, ICC = 0.924). The current study demonstrated a reasonable reproducibility of estimated peak power and pedal velocity outputs in non-elite male athletes and supports that a familiarization session including a complete FVT protocol is not required.</p></div