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:
Jul. 11, 1995
Filed:
Oct. 28, 1993
Masao Takuma, Toyonaka, JP;
Kiyotada Kawakami, Osaka, JP;
Sanyo Electric Co., Ltd., , JP;
Abstract
An automatic focusing apparatus includes a focus lens, an image sensing circuit, a circuit for generating a focus evaluating value in response to a video signal from image sensing circuit, a hill-climbing control circuit, a focus motor for moving focus lens in response to a control signal from hill-climbing control circuit, and a circuit for detecting the position of focus motor. The focus evaluating value generating circuit includes an A/D converter, a digital HPF, a digital integrator for integrating the level of the high frequency component in a digital luminance signal in response to a control signal from an integration period setting circuit and sequentially supplies the resultant value as a focus evaluating value to the hill-climbing control circuit for every field, and a timer circuit for producing a reset signal at H level. Thus, after passage of prescribed time period from the end of the horizontal blanking period, a reset signal is applied to digital HPF, delay register in the digital HPF is set to zero, and the digital HPF is reset. Ringing due to a rising in the horizontal blanking period disappears, part of ringing will not be integrated, and therefore accurate automatic focusing operation can be performed.