CA2027515A1 - Preflash measurement technique - Google Patents

Preflash measurement technique

Info

Publication number
CA2027515A1
CA2027515A1 CA 2027515 CA2027515A CA2027515A1 CA 2027515 A1 CA2027515 A1 CA 2027515A1 CA 2027515 CA2027515 CA 2027515 CA 2027515 A CA2027515 A CA 2027515A CA 2027515 A1 CA2027515 A1 CA 2027515A1
Authority
CA
Canada
Prior art keywords
electronic flash
exposure
scene
arrangement
light
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
CA 2027515
Other languages
French (fr)
Other versions
CA2027515C (en
Inventor
Judith Neely Coltman
John P. Gaewsky
Jeffrey T. Gray
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.)
Polaroid Corp
Original Assignee
Polaroid Corp
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 Polaroid Corp filed Critical Polaroid Corp
Priority to CA 2027515 priority Critical patent/CA2027515C/en
Publication of CA2027515A1 publication Critical patent/CA2027515A1/en
Application granted granted Critical
Publication of CA2027515C publication Critical patent/CA2027515C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Landscapes

  • Stroboscope Apparatuses (AREA)
  • Exposure Control For Cameras (AREA)

Abstract

An automatic exposure control system for an electronic flash camera incorporates an arrangement for measuring the reflectivity of a scene illuminated by the electronic flash prior to exposure in order to determine certain photographic scene characteristics for use in controlling a subsequent photographic exposure, an arrangement that substantially reduces the complexity and energy consumption of the electronic flash system while improving the ability of the exposure control system to accurately determine these scene characteristics. The arrangement includes the pre-exposure firing of the electronic flash to illuminate a scene with a pulse of light for a short, fixed period of time.
A reflection of this light pulse is integrated for a portion of this fixed period of time. The final integrated value of the reflected light is a measure of subject reflectivity. This integrated value is then employed to derive the desired photographic scene characteristics.
CA 2027515 1990-10-12 1990-10-12 Preflash measurement technique Expired - Fee Related CA2027515C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA 2027515 CA2027515C (en) 1990-10-12 1990-10-12 Preflash measurement technique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA 2027515 CA2027515C (en) 1990-10-12 1990-10-12 Preflash measurement technique

Publications (2)

Publication Number Publication Date
CA2027515A1 true CA2027515A1 (en) 1992-04-13
CA2027515C CA2027515C (en) 2000-07-25

Family

ID=4146148

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 2027515 Expired - Fee Related CA2027515C (en) 1990-10-12 1990-10-12 Preflash measurement technique

Country Status (1)

Country Link
CA (1) CA2027515C (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11294054B2 (en) * 2019-10-11 2022-04-05 Dell Products L.P. Information handling system infrared proximity detection with ambient light management
US11334146B2 (en) 2020-01-31 2022-05-17 Dell Products L.P. Information handling system peripheral enhanced user presence detection
US11435447B2 (en) 2019-10-11 2022-09-06 Dell Products L.P. Information handling system proximity sensor with mechanically adjusted field of view
US11435475B2 (en) 2019-10-11 2022-09-06 Dell Products L.P. Information handling system infrared proximity detection with frequency domain modulation
US11513813B2 (en) 2020-01-31 2022-11-29 Dell Products L.P. Information handling system notification presentation based upon user presence detection
US11662695B2 (en) 2019-10-11 2023-05-30 Dell Products L.P. Information handling system infrared proximity detection with distance reduction detection
US11663343B2 (en) 2020-01-31 2023-05-30 Dell Products L.P. Information handling system adaptive user presence detection

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112346110B (en) * 2020-10-30 2023-03-24 中国核工业第五建设有限公司 Handwriting mark pre-exposure cassette for automatic ray detection system

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11294054B2 (en) * 2019-10-11 2022-04-05 Dell Products L.P. Information handling system infrared proximity detection with ambient light management
US11435447B2 (en) 2019-10-11 2022-09-06 Dell Products L.P. Information handling system proximity sensor with mechanically adjusted field of view
US11435475B2 (en) 2019-10-11 2022-09-06 Dell Products L.P. Information handling system infrared proximity detection with frequency domain modulation
US11662695B2 (en) 2019-10-11 2023-05-30 Dell Products L.P. Information handling system infrared proximity detection with distance reduction detection
US11334146B2 (en) 2020-01-31 2022-05-17 Dell Products L.P. Information handling system peripheral enhanced user presence detection
US11513813B2 (en) 2020-01-31 2022-11-29 Dell Products L.P. Information handling system notification presentation based upon user presence detection
US11663343B2 (en) 2020-01-31 2023-05-30 Dell Products L.P. Information handling system adaptive user presence detection

Also Published As

Publication number Publication date
CA2027515C (en) 2000-07-25

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Legal Events

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