Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1992-09-04
1993-11-09
Perkey, W. B.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358227, G03B 1336
Patent
active
052607364
ABSTRACT:
A broad band pass filter and a narrow band pass filter are provided. The broad band pass filter detects a moving direction of the focus lens certainly and a peak of the evaluative value rapidly. And then, the band pass filter means is switched to the narrow band pass filter. The narrow band pass filter confirms whether a detected peak is correct or not. It is compared with a brightness when the evaluative value is peak and a brightness at a moment mhe the evaluative value is not peak, for example, an evaluative value is minimum. If a difference of brightness becomes large, it is not recognized as a peak and a peak detection is repeated. A gain value of the amplifier is reduced corresponding to a linear-, step- or curve characteristicline between a focus position of the focus lens and a focus distance of the zooming lens when a gain value of the automatic gain control (AGC) circuit is relatively high, so that a noise component in a high frequency part is reduced. In the case that an iris is relatively closed, a gain of the AGC is relatively high or a gain of the amplifier circuit is relatively high, a noise component becomes large so that the reference value becomes high in order to judge a peak of an evaluative value certainly. On the other hand, in the case that the iris is relatively opened, a gain value of the automatic gain control circuit is relatively low or a gain value of the amplifier circuit is relatively low, a noise component becomes low in order to detect a peak rapidly without a focus lens running over a focus point.
REFERENCES:
patent: 4383274 (1983-05-01), Inuiya
patent: 4833541 (1989-05-01), Takuma et al.
patent: 4967280 (1990-10-01), Takuma
patent: 5150217 (1992-09-01), Senuma et al.
Fuji Photo Film Co. , Ltd.
Perkey W. B.
LandOfFree
Auto focus control device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Auto focus control device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Auto focus control device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1146288