Image recording system and method

• US 5,006,871 A
• Filed: 05/23/1990
• Issued: 04/09/1991
• Est. Priority Date: 05/23/1990
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Noble, Stephen A.
• Primary Examiner(s): Perkey, W. B.
• Assistant Examiner(s): NOH, JAE
• Application Number:
  US07/528,000
• Time in Patent Office: 321 Days
• Field of Search: 358/909, 358/906, 358/209, 358/213.13, 358/213.19, 358/225, 358/278, 354/75, 354/76, 354/432, 354/412, 354/145.1, 354/413
• US Class Current: 348/64
• CPC Class Codes: H04N 23/00 Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means

Abstract

A system for simultaneous recording of a flash image on photographic film and video cameras in which flash operation during transfer of image out of the image sensor in the video camera is avoided by means of a simple synchronizing circuit. The synchronizing circuit generates a flash valid signal which allows the flash to be initiated only during a limited portion of the video field signal ending sufficiently far in advance of the next vertical blanking interval to assure that any flash illumination will be completed before the beginning of the next vertical blanking interval in which the video image transfer process occurs.

Claims

1. An image recording system for simultaneously recording images of a subject in electronic and photosensitive media, comprising:

a photographic camera for capturing a photographic image of said subject on said photosensitive medium, said photographic camera including means for supplying a flash request signal;

a video camera for generating a video signal comprised of alternating video image fields and vertical blanking intervals, said camera including solid state imaging means for capturing a video image of said subject and means for processing said captured image during said vertical blanking intervals into successive fields of video image signals;

means for illuminating said subject with a flash illumination of a predetermined maximum duration;

means for separating vertical blanking signals from said camera video signal; and

flash synchronizing means responsive to said separated vertical blanking signals for enabling initiation of said flash illumination only during a limited time interval following each successive vertical blanking interval, said limited time interval ending at a point in the video signal image field that assures that a flash illumination of said maximum duration initiated at any time in said limited time interval will be substantially completed before the processing of the captured image from said imaging means is initiated in the next successive vertical blanking interval.

2. The image recording system of claim 1, in which said synchronizing means includes means responsive to said vertical blanking signals for generating a flash valid signal active only during said limited time interval and means responsive to time concident occurrence of said flash valid and flash request signals to generate a flash fire signal, said flash illumination means being responsive to said flash fire signal for initiating said flash illumination.

3. The system of claim 1 further including image store means for storing video image information from at least one video image field from said video camera;

and means responsive to said flash synchronizing means for enabling said image store means to store at least the first video field following the field in which said flash is enabled.

4. The system of claim 3 in which said image store means, when enabled in response to the flash synchronizing means stores a complete frame of two successive image fields commencing with the first field following the field in which said flash is enabled.

5. Apparatus for use in synchronizing flash illumination by flash apparatus in an image recording system which simultaneously records an image of a subject in photographic film and video cameras, the apparatus comprising:

means responsive to a vertical blanking signal in the video signal from the video camera for generating a flash valid signal ending at a predetermined point prior to the next successive vertical blanking interval;

means responsive to simultaneous presence of said flash valid signal and a flash request signal from the photographic film camera for generating a flash fire signal adapted to be applied to said flash apparatus to initiate said flash illumination;

the predetermined ending point of the flash valid signal being such as to assure substantial completion of the flash illumination prior to commencement of the next successive vertical blanking interval.

6. The apparatus of claim 5 for a system further including an image store means wherein the apparatus further includes means responsive to the flash valid signal for enabling storage by the image store means of at least one full field of image information from the video camera immediately following the field in which initiation of said flash illumination occurs.

7. A method of recording an image of a subject substantially simultaneously on electronic and photosensitive mediums with a single flash illumination comprising the steps of:

initiating the recording of a photographic image of said subject on a photosensitive medium;

generating a flash request signal for the purpose of initiating a flash illumination of said subject to be effective during recording of the photographic image;

capturing a video image of said subject on an electronic image sensor of the electronic medium;

transferring the captured image from the sensor into a video signal processing circuit during vertical blanking intervals in the video signal;

synchronizing the flash illumination with the video signal by generating a flash valid signal only during a limited time interval in a video field that assures that any flash illumination on the subject will be substantially completed prior to transfer of a field of video image from the image sensor during the next successive vertical blanking interval;

generating a flash request signal; and

initiating flash illumination on the subject only during coincidence of the flash request and flash valid signals.