Open AccessEXPERIMENTAL ASSESSMENT OF THE EFFECT OF EXPOSURE LEVEL ON THE RESOLUTION OF A DIGITAL PHOTOGRAPHIC SYSTEM
Author(s) -
Diana Pivtorak
Publication year - 2021
Publication title -
vìsnik kiïvsʹkogo polìtehnìčnogo ìnstitutu. serìâ priladobuduvannâ/vìsnik kiïvsʹkogo polìtehnìčnogo ìnstitutu. serìâ priladobuduvannâ
Language(s) - English
Resource type - Journals
eISSN - 2663-3450
pISSN - 0321-2211
DOI - 10.20535/1970.61(1).2021.237079
Subject(s) - computer science , computer vision , artificial intelligence , contrast (vision) , shutter , brightness , frame (networking) , energy (signal processing) , optics , mathematics , statistics , physics , telecommunications
While photographing in a wide range of brightness within the frame, the exposure devices must provide exposure control for each elementary area of the frame, i.e., provide local exposure control. Cameras which equipped by well-known exposure devices with local exposure control is used a multiplicative, additive or multifunction method of image recording.
Using of the multiplicative method leads to energy losses in the optical channel, which requires correction of the exposure control parameters. Using of the additive method makes it possible to reduce the effective shutter speed, but reduces the contrast of small images. The multiplicative method of image registration allows to suppress low-informative low-frequency components of the spectrum of the input signal, providing less losses from the image blur according to the multiplicative method and less losses from reducing the contrast of images of small parts according to the additive method.
Comparative evaluation of cameras’ effectiveness which are equipped by exposure devices with local exposure control, which are based on different methods of image registration, is convenient to assess the criterion of "resolution averaged over the frame field". According to the developed methodology of evaluating the effectiveness of this type of cameras, the averaged field resolution can be calculated in several ways, each of which assumes a preliminary calculation or obtaining the dependence of resolution from exposure (resolvometric characteristics of the camera).
The methodology of experimental determination of the resolvometric characteristic of a photographic image recorder equipped by exposure devices of local exposure control is proposed. This methodology is illustrated by the example of measuring the resolvometric characteristics of the digital camera nex-6 for different external conditions. The good convergence of results of theoretical and experimental researches is shown. The proposed methodology can be used in studies of the impact of the process of the multifunction method of image recording on the photographing efficiency.
Keywords: image; resolution; measure; camera