Metoda pomiaru wskaźnika UGR z wykorzystaniem kamery z detektorem CCD

W artykule opisano wyniki badań mających na celu opracowanie metody pomiaru olśnienia przykrego, wykorzystującej kamerę z matrycą CCD. Przedstawiono ogólne informacje na temat olśnienia i dotychczasowych prób jego oceny. Zaprezentowano oryginalną metodę pomiaru wielkości niezbędnych do wyznaczenia wskaźnika UGR, którą poparto wynikami badań eksperymentalnych. Dzięki temu wykazano możliwość pomiaru olśnienia przykrego za pomocą miernika w konfiguracji cyfrowej kamery otworkowej.

In the paper the results of investigations on elaboration of a discomfort glare measurement method are described. This method uses a camera with CCD matrix. In the introduction some general information about glare [1, 2, 3, 4, 5, 6] and attempts to measure it [7] are presented. Besides, the most reliable system of glare evaluation - called the unified glare rating system UGR [8, 9] - is introduced. It imposes the necessity of estimation of the following quantities: background luminance, luminance of glare sources, their angular size and spatial arrangement (Fig. 1). A novel method for measurement of these quantities and, as a result, of the UGR index is described in Paragraph 2. It uses a pinhole digital camera. In practice this method consists in taking a series of images of the analysed area in the investigated interior. These images are used to calculate the background luminance, the luminance of each source within the field of view, their Guth position indexes and solid angles [7, 8]. It is done on a basis of the brightness analysis and localization of each pixel on the image (Figs. 2 and 3). After including parameters of the imaging system these results give information about the searched quantities. In Paragraph 3 the structure and most important parameters [7, 10, 11] of the research stand (from the photometry point of view) are described. If the luminance distribution is included by the single image, the luminance distribution measurement uncertainty is 6,83%. The exemplary results of the UGR index measurements are presented in Paragraph 4. For the luminance distribution simulated in a laboratory and contained in the field of view of the imaging system the maximum error was 6,9%. In a real didactic room this error was about 28%. In conclusions the discussion of the presented results is carried out. The possible directions of later investigations are suggested.