Fuji Photo Film Company, Limited

Nobutaka Fukai

Toshitaka Agano

Akira Yamaguchi

Tsutomu Kimura

Yuji Ohara

Terumi Matsuda

An image signal is read by scanning a stimulable phosphor sheet on which radiation image information is recorded, with a stimulating light beam to cause the stimulable phosphor sheet to emit light representative of the recorded radiation image information, and photoelectrically detecting the emitted light. A change in the scanning speed at which the stimulable phosphor sheet is scanned with the stimulating light beam, is determined, and a corrective signal is determined based on the determined change in the scanning speed and a corrective coefficient established by at least reading conditions employed to read the radiation image information. The image signal is corrected with the corrective signal.

Method of and apparatus for correcting image signal

An object such as a stimulable phosphor sheet on which image information is recorded is scanned by a light beam such as a laser beam, and light bearing the image information from the object is photoelectrically detected to produce an image signal representing the image information. A monitor signal representing the light beam is divided into a high-frequency component and a low-frequency component. A corrective signal is produced multiplying a ratio of the high-frequency component to the low-frequency component by a constant. The corrective signal is then subtracted from the image signal.

A cassette for erasing remnant radiation images on a stimulable phosphor sheet without the necessity of taking out the sheet includes a casing for accommodating the stimulable phosphor sheet and a cover pivotally mounted to the casing so as to be opened or closed. The cassette also includes a light reflecting member for reflecting or diffusing the light introduced from outside the cassette for irradiation on an image recording region of the sheet, or a light transmitting member for transmitting the light introduced from outside the cassette or the light from an inner light source, or a light emitting device mounted at least in register wiht the image recording area of the stimulable phosphor sheet contained in the cassette. An erasure device for a stimulable phosphor sheet employing the cassette is adapted to erase radiation energies stored in the sheet by irradiating the sheet with an erasure light, and includes a housing, a device provided in the housing for opening the cassette placed at a predetermined position within the housing and accommodating the stimulable phosphor sheet to be erased, and a light source device provided in the housing and adapted for irradiating the erasure light on the stimulable phosphor sheet within the cassette in the opened state. The arrangement is suitably applied to cases wherein the stimulable phosphor sheet is stored without being used for prolonged time, in which cases the sheet may be employed directly since the secondary erasure directly before usage of the sheet is not required.

Cassette and erasure device for stimulable phosphor sheet

A scanning read-out apparatus comprises a device for detecting the scanning speed of a light beam and generating a scanning speed signal, and a device for calculation between a read-out signal detected by scanning of a read-out objective and the scanning speed signal and for generating a corrected read-out signal representing the result of the calculation. A coefficient for correction of the read-out signal is adjusted by forcibly fluctuating the scanning speed of the light beam on a read-out objective for correction coefficient adjustment, generating a correction signal by multiplying the scanning speed signal by an arbitrary coefficient, correcting the read-out signal by using the correction signal, extracting a signal of a noise component caused by the forcible fluctuation from the corrected read-out signal, finding the coefficient at which the extracted signal becomes the minimum, and using the coefficient thus found as the correction coefficient.

Scanning read-out apparatus with scanning speed fluctuation compensating

A sawtooth voltage waveform for driving a galvanometer mirror is applied until the voltage reaches a peak value exceeding a prescribed voltage value at which the galvanometer mirror is angularly displaced through a maximum angle at one stroke end of reciprocating angular movement thereof. The voltage is then changed from the peak value to the prescribed voltage value after the galvanometer mirror has been angularly displaced through the maximum angle. The voltage is kept at the prescribed voltage value for a time interval to attain a desired period of the reciprocating angular movement of the galvanometer mirror. The voltage may be increased along a ramp or reduced along a fall toward the peak value.

Method of driving galvanometer mirror

A recording medium scanning system includes a light source for generating a scanning light beam, a light modulator for modulating the light beam with a modulating signal, and a scanner for scanning a recording medium with the modulated light beam emitted from the light modulator. The scanning speed of a light beam emitted from the scanning means is detected by a scanning speed detector which issues a scanning speed signal indicative of the detected scanning speed. An arithmetic operation such as a multiplication or a division is effected on the scanning speed signal issued from the scanning speed detector and a recording signal. The result of the arithmetic operation is applied as the modulating signal to the light modulator.

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Kanagawa, Japan

Nobutaka Fukai