Fuji Photo Film Company, Limited

Hirosi Tanaka

Nobuyoshi Nakajima

Tokukazu Saito

Nobuaki Higashi

Kazuo Horikawa

Hisatoyo Kato

Takao Komaki

In a radiation image recording and reproducing system, an image signal obtained by forming a radiation image by a radiation passing through an object and photoelectrically detecting the radiation image is subjected to frequency processing by use of a predetermined degree of enhancement. The degree of enhancement is corrected in accordance with the radiation exposure dose so that the degree of enhancement is decreased as the exposure dose decreases, thereby improving the image quality of a reproduced visible image.

Frequency processing method and apparatus for radiation image

In a radiation image recording and reproducing system wherein preliminary read-out and final read-out are conducted for detecting a radiation image stored in a stimulable phosphor sheet, a characteristic value of the radiation image information of a specific region of the stimulable phosphor sheet is calculated on the basis of the radiation image information of the specific region obtained by the preliminary read-out. Final read-out conditions and/or image processing conditions are adjusted on the basis of the characteristic value, thereby simplifying the algorithm for the adjustment.

Method of adjusting radiation image read-out conditions and/or image

A method of adjusting radiation image read-out conditions used in a radiation image recording and reproducing system wherein preliminary read-out and final read-out are conducted for detecting the radiation image stored in a stimulable phosphor sheet. The method comprises determining a histogram of the amount of light emitted by the stimulable phosphor sheet when it is exposed to stimulating rays during the preliminary read-out. From the histogram, the maximum light emission amount Smax and the minimum light emission amount Smin of a desired image information range are calculated. Read-out conditions are adjusted so that Smax and Smin correspond respectively to the maximum signal level Qmax and the minimum signal level Qmin of a desired input signal range in an image processing apparatus which are determined by the maximum density Dmax and the minimum density Dmin of a correct density range in a finally reproduced visible image.

Method of adjusting radiation image read-out conditions

In a system for reading out a radiation image stored in a stimulable phosphor sheet and processing the gradation of the image, final read-out is conducted by use of a read-out condition GP determined on the basis of image information obtained by preliminary read-out. On the basis of the image recording portion and/or image recording conditions, the system selects whether to directly subject the output of the final read-out conducted by use of a read-out condition GP to a gradation processing under a gradation processing condition GH predetermined in accordance with the image recording portion and/or image recording conditions or to subject the output to a gradation processing effected by use of a gradation processing condition A(GP)xGH where A(GP) denotes the function determined by the image recording portion and/or image recording conditions.

Radiation image read-out and gradation processing method and apparatus

A method of adjusting radiation image read-out conditions used in a radiation image recording and reproducing system wherein preliminary read-out and final read-out are conducted for detecting the radiation image stored in a stimulable phosphor sheet comprises the step of determining a histogram of the amount of light emitted by the stimulable phosphor sheet when it is exposed to stimulating rays during the preliminary read-out. Read-out conditions are adjusted on the basis of a histogram section ranging from the maximum light emission amount in the histogram to a value determined by image recording conditions.

Method of adjusting radiation image read-out condition

In a method of reading out a radiation image stored in a stimulable phosphor sheet by scanning the stimulable phosphor sheet by stimulating rays, preliminary read-out and final read-out are conducted. The read-out line density of the stimulating rays in the final read-out is detected in advance. Image read-out conditions and/or image processing conditions adjusted on the basis of image information obtained by the preliminary read-out are corrected in accordance with the read-out line density in the final read-out so that the same final read-out image information and/or the same image signal after image processing is obtained from the stimulable phosphor sheet carrying the same image information stored therein.

Radiation image read-out method

A stack of many stimulable phosphor sheets and an X-ray tube are positioned with an object intervening therebetween, and moved with respect to each other around a tomographic plane in the object so as to satisfy the linear rule and the geometric rule in the course of exposure of the object to X-rays, thereby storing images of many tomographic planes in the stimulable phosphor sheets in a single recording step. The respective stimulable phosphor sheets are then exposed to a stimulating ray to cause them to emit light, the emitted light is photoelectrically read out, and the obtained electric signals are reproduced as visible tomographic images usable in diagnosis with high efficiency and accuracy. The electric signals may be superposed one upon another and reproduced as an X-ray image of any slice thickness, particularly a slice thickness of 5 mm or more, which is free from interfering shadows.

Method of recording X-ray image

In a radiation image read-out system wherein a stimulable phosphor sheet carrying a radiation image stored therein is exposed to stimulating rays which cause it to emit light in proportion to radiation energy stored therein, and the emitted light is photoelectrically read out, preliminary read-out is conducted to investigate the image input information in the stimulable phosphor sheet by use of stimulating rays having a wavelength different from the wavelength of stimulating rays employed in final read-out.

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Kanagawa, Japan

Hirosi Tanaka