Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1989-09-06
1992-02-11
Perkey, W. B.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358 29, 35821319, G03B 708
Patent
active
050879367
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.
REFERENCES:
patent: 4595946 (1986-06-01), Uehara et al.
patent: 4774588 (1988-09-01), Noda et al.
"Fundamentals of Physics", Halliday and Resnick, New York, 1981, p. 324.
"Communications Systems-An Introduction to Signals and Noise in Electrical Communication", Carlson, New York, 1988 pp. 345-347.
"Electronic Engineer's Handbook", Fifth Edition, Section 31/8-31/11, Section 36/1-36/18 and 37/1, Mazda et al.
Kaneko Kiyotaka
Kaneko Kouji
Mikajiri Satoshi
Ogata Kazutsugu
Seki Kazuhisa
Fuji Photo Film Co. , Ltd.
Perkey W. B.
Spyrou Cassandra C.
LandOfFree
Camera does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Camera, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Camera will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-784342