KEYWORDS: Charge-coupled devices, Image processing, Signal processing, Cameras, Digital signal processing, Photodiodes, Digital cameras, Image quality, Digital image processing, CCD cameras
Recently the digital still camera (DSC) has achieved remarkable progress especially in terms of pixel numbers, and 3 mega-pixel cameras have become the main stream. This is owing to the progress of semi-conductor processing technology and DSC market demand. On the other hand, there are some problems accompanying increase of pixel numbers, for example degradation of S/N and increase of shooting interval. For the product described here we have applied miniaturization processing technology to incresing the dynamic range and have developed a Super Dynamic Range Image Processing System using a new structure CCD, in which a pair of different-type photodiodes is arranged under a micro lens that is located on the top surface. This makes it possible to capture a high contrast scene in which dynamic range is about 400%, and we have achieved distinct images of difficult scenes for a DSC to reproduce such as backlight scenes, short range stroke light photography, etc. Here, we explain the new CCD and LSIs which realize the super dynamic image processing system, and its algorithm.
Digital still cameras are getting popular not only in the professional market but also in the consumer market. In recent years, the number of pixels employed in consumer digital still cameras is increasing dramatically, resulting in that over a half of the digital still cameras currently used in the market have over 2 mega pixels. As the number of pixels increases, the ability to depict fine details is improved steadily. Although the resolution is one of the important factors of image quality, current consumer digital cameras seem to have adequate pixels if the resultant image is to be displayed on a monitor or to be printed in small size. In this paper, first we review some important aspects to improve image quality of consumer digital still cameras. Then we propose our new conceptual CCD, which enables capture of a wider dynamic range. The new technology to realize a wider dynamic is introduced and new algorithm to utilize such dynamic range is described also.
A new psychophysical experimental method is proposed for estimating image quality. The method comprises two steps; the first step is a 'categorical session' and the second step is a 'triplet comparison session' which is newly developed for this purpose. The triplet comparison method is developed, in order to improve the assessment accuracy and repeatability, without imposing excess observer stress during the visual assessment. Moreover, since the triplet comparison inevitably reduces the number of comparisons, experimenter can design psychophysical experiments using a higher number of samples, compared to the paired comparison method. A series of psychophysical experiments were conducted and performed. It is found that the proposed method gives reliable and stable results so far examined.
We have already proposed a standard portrait for the assessment of preferable skin tone. The present report describes a psycho physical experimental method, i.e., simultaneous triplet comparison that has been developed for the assessment of skin tone by using the portrait and that is characterized not only by a scalability, stability and reproducibility of the resulting scale values, but also by a reduce stress on observers. We have confirmed that the present simultaneous triplet comparison has a degree of scalability and stability almost equivalent to that of paired comparison that is most widely used for similar purposes, and that the stress on observers is about half as much as that of paired comparison.
KEYWORDS: Cameras, Photography, Printing, Computer programming, RGB color model, Digital photography, Algorithm development, Digital cameras, Data modeling, CRTs
The expansion of digital still cameras into the consumer market has provided opportunities for photographic amateurs to enjoy new digital imaging. Fuji Photo Film Co., Ltd. has started the Fiji Digital Imaging Service (F-DI) from 1997. The F-DI DSC print service is one of the features which provides photographic prints from the data obtained by digital still cameras. Below, the concept of the F-DI DSC print service is described and the algorithm adopted for printing is discussed. Since digital still cameras are developed such that the images will originally be displayed on CRT monitors, it is necessary to achieve new technical development for this particular service. New algorithms including the scene color balance algorithm and the density correction algorithm are described. The conditions necessary to obtain excellent prints are also explained.
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