JPS6416179A - Automatic focusing device - Google Patents

Automatic focusing device

Info

Publication number
JPS6416179A
JPS6416179A JP62171067A JP17106787A JPS6416179A JP S6416179 A JPS6416179 A JP S6416179A JP 62171067 A JP62171067 A JP 62171067A JP 17106787 A JP17106787 A JP 17106787A JP S6416179 A JPS6416179 A JP S6416179A
Authority
JP
Japan
Prior art keywords
converter
value
output
substracter
detector
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP62171067A
Other languages
Japanese (ja)
Other versions
JP2701262B2 (en
Inventor
Kunihiko Yamada
Masamichi Toyama
Akihiro Fujiwara
Hiroshi Suda
Katsuji Yoshimura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Priority to JP62171067A priority Critical patent/JP2701262B2/en
Publication of JPS6416179A publication Critical patent/JPS6416179A/en
Application granted granted Critical
Publication of JP2701262B2 publication Critical patent/JP2701262B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Landscapes

  • Focusing (AREA)
  • Automatic Focus Adjustment (AREA)

Abstract

PURPOSE:To keep a bit rate at a time to A/D convert a focus evaluating value in a necessary minimum by providing a subtracting means to obtain the differential value of a prescribed component per prescribed period and minimumizing the range of an analog signal inputted to an A/D converting means. CONSTITUTION:A sample and hold circuit 34 samples the output of a detector 32 according to the signal of a timing corresponding to the vertical synchronizing signal of a video signal and holds it for an IV period. A substracter 36 substracts the hold value of the sample and hold circuit 34 from the output voltage of a detector 32 and outputs the substracted voltage. An amplifier 38 amplifies the output voltage of the substracter 38 and impresses it to an A/D converter 40. An operation processing circuit 42 adds the output of the A/D converter 40 per IV, calculates the driving direction and the driving speed of a motor 24 and outputs them to a D/A converter 44. Thus, since a little bit number can be efficiently used and a digital value can be accurately reproduced, the accuracy of a down-hill control can be enough secured.
JP62171067A 1987-07-10 1987-07-10 Automatic focusing device Expired - Fee Related JP2701262B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62171067A JP2701262B2 (en) 1987-07-10 1987-07-10 Automatic focusing device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62171067A JP2701262B2 (en) 1987-07-10 1987-07-10 Automatic focusing device

Publications (2)

Publication Number Publication Date
JPS6416179A true JPS6416179A (en) 1989-01-19
JP2701262B2 JP2701262B2 (en) 1998-01-21

Family

ID=15916431

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62171067A Expired - Fee Related JP2701262B2 (en) 1987-07-10 1987-07-10 Automatic focusing device

Country Status (1)

Country Link
JP (1) JP2701262B2 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5988976U (en) * 1982-12-06 1984-06-16 三洋電機株式会社 Auto focus control circuit
JPS63232757A (en) * 1987-03-20 1988-09-28 Victor Co Of Japan Ltd Auto-focus system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5988976U (en) * 1982-12-06 1984-06-16 三洋電機株式会社 Auto focus control circuit
JPS63232757A (en) * 1987-03-20 1988-09-28 Victor Co Of Japan Ltd Auto-focus system

Also Published As

Publication number Publication date
JP2701262B2 (en) 1998-01-21

Similar Documents

Publication Publication Date Title
EP0361452A3 (en) Digital automatic gain control apparatus and method
JPS5776974A (en) Method and apparatus for read-in of radiant rays picture information
GB2144216B (en) Opto-electronic position sensing
EP0178044A3 (en) Analogue-to-digital converting apparatus for video signals
JPS6416179A (en) Automatic focusing device
JPS56126390A (en) A-d converting circuit of video signal
FR2363940A1 (en) APPARATUS AND METHOD FOR TRANSFORMING DIGITAL SIGNALS
JPS5559411A (en) Focus point detector
JPS57138262A (en) Conversion system for main scanning line density
JPS5742282A (en) A/d converter for output video signal of vtr
JPS57203843A (en) Air-fuel ratio feedback control device
EP0062205A3 (en) Electronic weighing apparatus
JPS5744867A (en) Measuring device for charge coupled element
JPS5720078A (en) Detector for synchronizing signal
JPS56124132A (en) Tracking control circuit for optical disc
JPS57169603A (en) Strain measuring method
JPS5719804A (en) Digital servo system
JPS6449131A (en) Servo method for optical recording and reproducing device
JPS57107688A (en) Sampling pulse correcting system
JPS57173284A (en) Automatic gain controller
JPS57130753A (en) Operator for speed of fluctuation of molten metal level in mold
EP0244980A3 (en) Rate-of-change signal generator and method using sampling techniques
JPS5722211A (en) Focusing detecting system
JPS5753369A (en) Ink jet printer
KR100238262B1 (en) Digital servo control circuit in an optical disc system

Legal Events

Date Code Title Description
LAPS Cancellation because of no payment of annual fees