Eastman-Kodak Company

Richard A Shroyer

Thomas C Nutting

David Andrew Johnson

William A Martin

A method of setting recorded data bit cell length on an APS film magnetic layer in a camera of the type having apparatus for normally setting bit cell length as a function of measured film transport velocity. The method comprises detecting the occurrence of an invalid film velocity measurement and substituting a default data recording frequency that results in a recorded bit cell length on the film which ensures that a maximum number of intended data bits are recorded in a given available length of data track which might otherwise not result if the invalid film velocity measurement were used to set the recorded bit cell length. Determination of invalid velocity measurement can be made by sensing mis-positioned film in the film gate at the start of film advance, for example by detecting alignment of a perf used for velocity measurement with the velocity determining optical sensor or by detecting a delay time between start of film advance and velocity perf detection that is less than a minimum threshold delay amount associated with normal film position. Alternatively, actual film velocity may be measured and a default bit cell length set when the measured velocity is outside a range of measured velocities associated with normal film advance operation.

Method of setting bit cell length for magnetic recording of data in a

A video still camera includes a common integrating circuit for measuring light level in relation to both color balance and exposure control. An exposure photodiode generates an exposure signal from a small sample of image light diverted from the optical section of the camera. Broadly oriented red, green and blue photodiodes generate three color balance signals corresponding to the color characteristics of the illuminant. The photodiodes are selectively multiplexed into the input of the integrating circuit for the measurements. In one embodiment, the exposure photodiode remains connected to the integrating circuit for exposure measurement. The color balance measurement is unaffected because the small photocurrent from the exposure photodiode is effectively swamped by the much larger color photocurrent from a multiplexed color photodiode.

Still video camera with common circuit for color balance and exposure

A still video camera includes an electronic image sensor as a signal source either for an electronic viewfinder or for a still image processed by the camera and recorded upon a magnetic disk. Since the viewfinder operates in a movie mode (with a fixed exposure time), the light intensity required for a viewfinder display ordinarily differs from that required for a still exposure. By commonly determining the correct exposure conditions for both the viewfinder display and the still exposure, time can be saved in shifting from the movie mode to the still mode. A sample of image light in the movie mode is diverted to a microprocessor-controlled exposure circuit, which integrates the light to determine the correct diaphragm aperture for both modes of operation. The movie aperture is directly input to a diaphragm driver while the still aperture is saved until a still exposure is requested.

Exposure control apparatus for a still video camera having an electronic

A film video player includes an electronic strobe light operable for repetitively firing a flash tube, to flash illuminate a solid state image sensor via a high-intensity light pulse projected onto photographic film at the vertical retrace rate of a standard television signal. A current sink circuit is provided for drawing a flash tube simmer current, to maintain an arc in the flash tube between sensor-illuminating pulses. Sensing circuitry, coupled to a junction common to the flash tube and the current sink circuit, produces a control signal corresponding to whether or not the flash tube is conducting simmer current. Switching circuitry, responsive to the control signal at the vertical retrace rate, (1) causes the overriding of the operation of a flash tube trigger circuit when the control signal indicates that the flash tube is conducting simmer current, and (2) causes the operating of the trigger circuit when the control signal indicates that the flash tube is not conducting simmer current. By providing for the triggering of the flash tube only when the simmer current is off, electromagnetic interference, which is produced by the flash tube trigger voltage and which can adversely affect the video display signal, is minimized.

Flash tube simmer circuitry for a film video player electronic strobe

A method and apparatus for discriminating among various types of illuminants, such as fluorescent light, incandescent light and natural daylight. Such apparatus includes a photoelectric circuit for producing a signal having an amplitude which varies with intensity variations of the illuminant, a bandpass filter circuit having a bandpass centered at the fundamental frequency of the intensity variations of an illuminant energized by an alternating current source, a high-pass filter circuit that passes frequencies higher than such fundamental frequency, a pair of peak detectors for detecting the peak value of signals passed by the first and second filter circuits, and logic circuitry responsive to the outputs of the peak detectors for providing logic outputs indicative of the type of illuminant.

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Rochester, NY, United States of America

Richard A Shroyer