The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 11, 1992
Filed:
Sep. 06, 1989
Kazutsugu Ogata, Omiya, JP;
Kazuhisa Seki, Omiya, JP;
Kouji Kaneko, Omiya, JP;
Satoshi Mikajiri, Omiya, JP;
Kiyotaka Kaneko, Tokyo, JP;
Masanori Yoshida, Tokyo, JP;
Fuji Photo Film Co., Ltd., Kanagawa, JP;
Abstract
A filter is provided which can pass therethrough only a signal component having a frequency corresponding to a secondary higher harmonic frequency component (200-240 Hz) of the fluorescent light of the output signal from a light-receiving element for receiving incident light thereto from the photograph area. Based on the signal which is passed through the filter, it is detected whether the photography area is illuminated with the fluorescent light. Since the color temperatures of sunlight (outdoors in fine weather) and fluorescent light show substantially the same value, it is difficult to distinguish two kinds of above light sources. A ripple period of the fluorescent light and the like is measured, and the output signal of a light detecting device (e.g., a color temperature sensor, photometry element, and so forth) is sampled at a plurality of times in a length of time equivalent to one period of the measured ripple period. Therefore, even for a photograph under artificial light which includes ripple components, an average of the quantity of the incident light can be detected and the white balance adjustment and the exposure control can be appropriately conducted. As a result, it is possible to distinguish between sunlight and fluorescent light and an accurate white balance adjustment can be made and the color reproducibility can be greatly improved even under fluorescent light.