Development of a webcam based lux meter

Abstract

The amount of light is an important issue in several scenarios ranging from scenic design, light pollution study, robots navigation, occupational health and safety, illumination engineering, agriculture, medical appliances and many more. It is typically determined by using an illumination meter. The meter, also known as lux meter is used to measure the density of light in an area which measured in lx unit. It is used in photometry as a measure of the intensity, as perceived by the human eye of light that hits or passes through a surface. As in normal meter, the lux value was obviously a displayed value, and hardly used for embedded application as well as for lighting monitoring considering its expensive price. This limits the lighting monitoring in certain critical field. Therefore, in this paper, we present our initial works on the development of a webcam based lux meter that is applicable and suitable for lighting monitoring as well as the ability to be used in embedded application. A series of controlled images are taken, and image processing is applied to the images. The results of image processing are statistically analyzed and a linear relationship between lux value and average grayscale has been obtained with satisfactory R2. The linear function is tested and the results are justified where the algorithm for low cost webcam-based digital lux meter has been successfully developed.