Demonstration Platform for Visual Quality Metrics

This thesis presents two graphical user interfaces for the project DigiQ - Fusion of Digital and Visual Print Quality, a project for computationally modeling the subjective human experience of print quality by measuring the image with certain metrics. After presenting the user interfaces, methods for reducing the computation time of several of the metrics and the image registration process required to compute the metrics, and details of their performance are given. The weighted sample method for the image registration process was able to signifigantly decrease the calculation times while resulting in some error. The random sampling method for the metrics greatly reduced calculation time while maintaining excellent accuracy, but worked with only two of the metrics.

Computational visual quality of digitally printed images

The problem of understanding how humans perceive the quality of a reproduced image is of interest to researchers of many fields related to vision science and engineering: optics and material physics, image processing (compression and transfer), printing and media technology, and psychology. A measure for visual quality cannot be defined without ambiguity because it is ultimately the subjective opinion of an “end-user” observing the product. The purpose of this thesis is to devise computational methods to estimate the overall visual quality of prints, i.e. a numerical value that combines all the relevant attributes of the perceived image quality. The problem is limited to consider the perceived quality of printed photographs from the viewpoint of a consumer, and moreover, the study focuses only on digital printing methods, such as inkjet and electrophotography. The main contributions of this thesis are two novel methods to estimate the overall visual quality of prints. In the first method, the quality is computed as a visible difference between the reproduced image and the original digital (reference) image, which is assumed to have an ideal quality. The second method utilises instrumental print quality measures, such as colour densities, measured from printed technical test fields, and connects the instrumental measures to the overall quality via subjective attributes, i.e. attributes that directly contribute to the perceived quality, using a Bayesian network. Both approaches were evaluated and verified with real data, and shown to predict well the subjective evaluation results.

Improving Quality of Life of Patients With Schizophrenia In Acute Psychiatric Wards

The overall goal of this study was to identify means by which the quality of life (QoL) of patients with schizophrenia could be improved in acute psychiatric wards. First, subjective QoL of patients (n=35) was explored. Second, two different QoL instruments (EuroQoL-5D, EQ-5D; Quality of Life Enjoyment and Satisfaction Questionnaire Short Form, Q-LES-Q SF) were examined. Third, patients’ (n=35) and nurses’ (n=29) perceptions of nursing interventions to support patients’ QoL were examined. Fourth, the effect of three different patient education methods on patients’ QoL (n=311) was compared. The data were collected during the period 2005-2007. Patients named health, family, leisure activities, work or study, and social relationships most frequently as their important QoL areas. It emerged that patients’ QoL was impaired. Examination of two QoL instruments showed that the EQ-5D has moderate and the Q-LES-Q SF good internal consistency. Moreover, both instruments proved to be reasonably valid and feasible for use with patients with schizophrenia. Altogether six nursing interventions which nurses use to support patients’ QoL, and which should be further developed were identified from nurses’ descriptions: interventions related to care planning, empowering interventions, social interventions, activating interventions, security interventions, and interventions to support physical health. Evaluation of different patient education methods showed that patients’ QoL improved significantly during follow-up. No significant differences between groups were found. In light of the findings it is recommended to assess QoL of patients with schizophrenia as a basis for care planning and care evaluation in clinical settings. Valid and feasible instruments should be used in this assessment. Moreover, it is recommend that nursing interventions should be further developed to better improve patients’ QoL.