Fuji Photo Film Company, Limited

Satoshi Iwamatsu

Nobuo Minoura

Katsuo Nakadai

Toshikatsu Harase

Masahiro Konishi

Hitoshi Koike

Kazuo Kawamura

The white peak level and black peak level of each of three types of color signals R, G and B obtained by picking up a negative image are detected. The amplitudes and levels of the signals are adjusted in such a manner that the white peak levels of the color signals R, G and B coincide as well as the black peak levels of these color signals. Signals representing the detected white peak and black peak levels are superimposed in first-half and second-half portions of a blanking interval of each of the color signals R, G and B. The signals that result can be utilized in subsequent signal processing. Also, the input/output characteristics of a gamma correction circuit are represented by an exponential function, which is for a gamma correction, up to a fixed input range, and by a KNEE curve, whose slope is smaller than that of the exponential curve, in a range beyond the fixed input range. Variable-gain amplifier circuits are provided in the front and in the back of the gamma correction circuit, and the range of the input/output characteristic curve used in the gamma correction circuit is adjusted. As a result, video signals having a variety of tone characteristics may be processed and in addition, it is possible to realize a variable gamma for obtaining tone characteristics suited to personal preferences.

Negative-image signal processing apparatus

A horizontal synchronizing reference signal producing circuit produces an internal horizontal synchronizing reference based upon an inputted clock and a reset pulse, a phase comparator compares the phases of a given external horizontal synchronizing reference and an internal horizontal synchronizing reference outputted by the horizontal synchronizing reference and generates a voltage signal conforming to a difference between the two compared phases. A low-pass filter then passes low-frequency components of the voltage signal outputted by the phase comparator, a VCO, whose frequency is controlled by an output voltage signal from the low-pass filter, generates a clock applied to the horizontal synchronizing reference signal producing circuit, a decision circuit determines whether the phase difference between the internal and external horizontal synchronizing reference signal lies within a range in which follow up is capable of being performed by the VCO. A reset pulse generator then generates a reset pulse synchronized to a prescribed edge of the external horizontal synchronizing reference and a reset control circuit inhibits input of the reset to the horizontal synchronizing reference signal producing circuit when the decision circuit determines that the phase difference lies within the follow-up range, and applies the reset signal to the horizontal synchronizing reference signal producing circuit when the decision circuit determines that the phase difference lies outside the follow-up range.

Horizontal synchronizing signal generating circuit

An image display system in which a plurality of magnetic recording/reproducing apparatus can be controlled via interfaces by a computer. The computer is adapted to output specification data for specifying one or more magnetic recording/reproducing apparatus to be controlled as well as control data including at least data on the shift of one or more magnetic recording/reproducing heads of the magnetic recording/reproducing apparatus to be specified. Each interface decodes the data input from the computer and transmits a given piece of control data to the magnetic recording/reproducing apparatus specified. The specified magnetic recording/reproducing apparatus shifts the magnetic recording/reproducing head in the radial direction of a rotating magnetic recording medium in accordance with the data on the shift of the magnetic recording/reproducing head applied through the above interface, and records signals into an arbitrary track or reproduces signals from an arbitrary track.

Image display system

Disclosed is an apparatus for gaining high-speed random access to a track in a magnetic recording/playback system of the type in which a magnetic head is shifted to an adjacent track in response to a forward-feed/reverse-feed signal and the head is positioned at the center of this track by tracking control. When the track number of a track to be accessed is designated, the designated track number is compared with a track number at which the magnetic head is presently located. An apparatus is provided for fast-feeding the magnetic head to a track adjoining the designated track on the basis of the comparison, and for subsequently outputting the forward-feed/reverse-feed signal for the purpose of tracking control.

Track access apparatus in a magnetic recording/playback system

Disclosed is an apparatus for gaining high-speed random access to a track in an existing magnetic recording/playback system of the type in which a magnetic head is shifted one track at a time to an adjacent track in response to a forward-feed/reverse-feed signal and the head is positioned at the center of this track by tracking control. When the track number of a track to be accessed is designated, the designated track number is compared with a track number at which the magnetic head is presently located. An apparatus is provided for fast-feeding the magnetic head to a track adjoining the designated track on the basis of the comparison, and for subsequently outputting the forward-feed/reverse-feed signal for the purpose of tracking control.

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Tokyo, Japan

Satoshi Iwamatsu