Fuji Photo Film Company, Limited

Fuji Photo Optical Co., Ltd.

Fujinon Corporation

Kazutsugu Ogata

Kiyotaka Kaneko

Satoshi Mikajiri

Kazuhisa Seki

Kouji Kaneko

Motohiko Horio

Izumi Miyake

Masahiro Konishi

Masanori Yoshida

Eiichi Hayashi

Kazukiyo Tamada

Koji Kaneko

Osamu Shinohara

Yuichi Ishiyama

Isumi Miyake

Speed fluctuations at a motor supplied with a two-phase current is reduced by changing the current value ratio at each phase in the drive current to feed a drive motor for an image reader to allow a light source lamp to move, free from speed fluctuations, to scan at a constant scanning speed. The drive motor is supplied with current different in value at each phase from constant current drive circuits, which, in one embodiment, are connected with current regulating variable resistors. An acceleration detector is fixed at the drive motor to detect acceleration fluctuations in rotation of the drive motor to detect speed fluctuations. In some embodiments, thermal control of the motor drive circuit is provided and vibration proofing to isolate the light receptor from the drive motor.

Method and device for pacing an image reader at a constant scanning speed

In an image reading device, light from a source document is formed in an image by an optical image-forming system including a lens and the formed image is detected by a charged coupled device (CCD) sensor. A reading line of the image read by the optical system and the CCD sensor is scanned in a vertical scanning direction. The charge accumulated in the CCD sensor is read out through a timing circuit and an analog-to-digital converter. Light from an extension of a reading line of a position-reading pattern in or on a position-reading plate is also formed into an image and detected by the CCD sensor, based on which, misregistration of a scanning position in the vertical scanning direction is detected. The image data read out by the CCD sensor is corrected by a correction circuit, based on the misregistration of a scanning position in the vertical scanning direction.

Image reading device

An electronic still camera which photographs an object by image pickup means such as a solid image pickup element or the like and records the video signal of the object into a rotary recording medium such as a magnetic disc or the like. The electronic still camera includes a mechanical shutter and an electronic shutter function to control electrically the accumulation time of the image pickup means and it is adapted such that, when the shutter speed is slower than a predetermined value, it controls a time for exposure to the image pickup means by the mechanical shutter and, when the shutter speed is higher than the predetermined value, it controls the exposure time to the image pickup means by means of the electronic shutter function and also controls the mechanical shutter to remain open at least for the exposure time.

Electronic still camera

An electronic still camera has a mechanical diaphragm mechanism for controlling the exposure of an image surface. The diaphragm mechanism includes an exposure plate having an opening of an aperture greater than an effective aperture corresponding to an open f-stop value, and at least one opening equal to an effective aperature corresponding to an f-stop value. By shifting the diaphragm plate, it is possible to set at least two types of f-stop values which include the open f-stop value. As a result, a diaphragm function in which effective aperture is made less than 1 mm can be achieved with a high degree of accuracy.

A filter is provided which can pass therethrough only a signal component having a frequency corresponding to a secondary higher harmonic frequency component (200-240 Hz) of the fluorescent light of the output signal from a light-receiving element for receiving incident light thereto from the photograph area. Based on the signal which is passed through the filter, it is detected whether the photography area is illuminated with the fluorescent light. Since the color temperatures of sunlight (outdoors in fine weather) and fluorescent light show substantially the same value, it is difficult to distinguish two kinds of above light sources. A ripple period of the fluorescent light and the like is measured, and the output signal of a light detecting device (e.g., a color temperature sensor, photometry element, and so forth) is sampled at a plurality of times in a length of time equivalent to one period of the measured ripple period. Therefore, even for a photograph under artificial light which includes ripple components, an average of the quantity of the incident light can be detected and the white balance adjustment and the exposure control can be appropriately conducted. As a result, it is possible to distinguish between sunlight and fluorescent light and an accurate white balance adjustment can be made and the color reproducibility can be greatly improved even under fluorescent light.

Camera

In a still-video camera, a video signal representing the image of a photographed subject is written in a video floppy during one revolution of the floppy, namely during an interval between one phase pulse PG and the next. Immediately after the phase pulse PG is generated, a field-shift pulse FS for reading the video signal out of an electronic image pick-up device is outputted. Read-out from the electronic image pick-up device by the field-shift pulse FS is inhibited during the time that a shutter is open. Writing is carried out from the moment of the next phase pulse PG after read-inhibit is cancelled. If the inhibition on read-out from the electronic image pick-up device were to be cancelled between the phase pulse PG and the field-shift pulse FS, read-out of the video signal by the field-shift pulse FS would be carried out, but it would not be possible to carry out recording without waiting for the next phase pulse PG. By providing reading and writing at timings as described above, it is possible to carry out recording without waiting for the next phase pulse PG.

Still-video camera for inhibiting read-out of a video signal when the

Method and device for measuring the brightness of an object in photographing the object in flash synchronization by use of an AE sensor capable of averaged overall light reading. In the method and device, in accordance with the distance of the object and also with the focal distance of a taking lens, an area occupied by a main object or a ratio of the occupation area on the light receiving surface of the AE sensor is estimated. Then, in accordance with said estimated occupation area or occupation area ratio of the main object and also with a measurement brightness B.sub.V(AV) measured by the AE sensor, there is found a brightness correction value .DELTA.B.sub.V which provides a value that increases as the occupation area of the main object increases and the measurement brightness B.sub.V(AV) measured by the AE sensor increases. Further, the thus obtained brightness correction value .DELTA.B.sub.V is added to the measurement brightness B.sub.V(AV) by the AE sensor to thereby find an object brightness.

Methods and device for measuring the brightness of an object

The present invention is concerned with an electronic still camera for photographing a subject by use of an image sensing device such as a solid state image sensing device and the image signal thereof is recorded into a rotary recording medium such as a magnetic disc. With this electronic still camera, photographing in an electronic view finder ( EVF) mode and a movie still mode in addition to a normal mode can be performed. The EVF mode is the mode for making exposure of the image of the subject to the normally open image sensing means by use of an electronic finder to observe the subject, and subsequently, releasing an exposure device for a period of time required for the exposure to make exposure of the image of the subject to an image sensing device. The movie still mode is the mode for steadily rotating a spindle motor in synchronism with a synchronous signal generator, outputting a video signal to the outside through an interface and recording a still image into the rotary recording medium in response to an exposure command.

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Omiya, Japan

Kazutsugu Ogata