Abstract: A radiation image of an object is formed with radiation, which has passed through the object. The radiation image is then photoelectrically read out, and an image signal made up of a series of image signal components representing the radiation image is thereby obtained. Frequency processing is carried out on the image signal in accordance with a predetermined emphasis coefficient .beta.. When the frequency processing is carried out on image signal components corresponding to a peripheral region in the radiation image, which peripheral region has a predetermined width, the value of the emphasis coefficient .beta. used during the frequency processing is decreased monotonously from a value for an image signal component corresponding to a position on the radiation image, which position is closer to the middle part of the radiation image, to a value for an image signal component corresponding to a position on the radiation image, which position is closer to the exterior of the radiation image.

Abstract: A radiation image read-out apparatus comprises an automatic developing machine for carrying out a developing process on silver halide film, on which a radiation image has been recorded as a latent image, while the silver halide film is being passed through the automatic developing machine. A film digitizer is connected to the automatic developing machine such that it may directly receive the silver halide film having been fed out of the automatic developing machine. The film digitizer photoelectrically reads out the radiation image, which has been converted into a visible image during the developing process, from the silver halide film and thereby generates an image signal representing the radiation image. The radiation image read-out apparatus is free of the problems in that considerable time and labor are required to set the film manually in the film digitizer, and the film becomes stained with finger marks, dust, or the like.

Abstract: An image read-out apparatus comprises a readout section for scanning a recording medium, on which an image has been recorded, in a main scanning direction and a sub-scanning direction, and thereby generating an image signal which has been sampled with a predetermined sampling density from the image, and an input section from which information about the type of the image and a high-density sampling instructing signal can be entered.

Abstract: A radiation image read-out apparatus comprises a read-out section for photoelectrically reading out a radiation image from silver halide film, on which the radiation image has been recorded, and thereby generating an image signal representing the radiation image. A signal conversion device converts the image signal such that distortion in the image signal, which distortion is caused to occur by nonlinear characteristics of the silver halide film, may be eliminated. A corrected image signal is thereby obtained, which can be processed commonly with an image signal obtained by reading out a radiation image from a stimulable phosphor sheet, on which the radiation image has been stored.

Abstract: An image processing apparatus processes diagnostic image data bearing thereon an image through which a disease is to be diagnosed so that a visible image having a quality optimal to diagnose the disease can be obtained. The image processing apparatus includes an image processing condition storage section and an image processing section. Names of various diseases and image processing conditions for the respective diseases are stored in the image processing condition storage section. The diagnostic image data is input into the image processing section. The name of a disease which is to be diagnosed is input into the image processing condition storage section, and the image processing condition corresponding to the disease is input into the image processing section from the image processing condition storage section. The image processing section carries out image processing on the image data according to the image processing condition input thereinto and generates a processed image data.

Abstract: In a radiation image processing apparatus, signal processing for determining the shape and location of an irradiation field, adjusting read-out conditions for a final readout from a preliminary read-out image signal, adjusting image processing conditions, and/or detecting an abnormal pattern is carried out on an image signal representing a radiation image by using a neural network. After the neural network, the learning operations of which have been carried out, is incorporated into the radiation image processing apparatus, modifying information is entered from an input device into the neural network. The modifying information is used to modify the signal processing carried out by the neural network and thereby to carry out re-learning operations of the neural network.

Abstract: An abnormal pattern detecting apparatus comprises an image operating device which generates a soft tissue image signal representing a soft tissue image, a bone image signal representing a bone image, and an original image signal representing an original image from several image signals representing radiation images of an object, which radiation images have been recorded by exposing the object to at least two kinds of radiation having different energy distributions. A prospective abnormal pattern finding device finds prospective abnormal patterns, which appear in the soft tissue, bone, and original images, by processing the corresponding image signals with an abnormal pattern finding filter. A bone pattern finding device finds information about the positions of bone patterns appearing in the radiation image.

Abstract: At least two stimulable phosphor sheets are exposed to at least two kinds of radiation, which have different energy distributions, without an object intervening between the stimulable phosphor sheets and a source of the radiation. The stimulable phosphor sheets are then exposed to stimulating rays, which cause them to emit light in proportion to the amount of energy stored thereon during their exposure to the radiation. The light emitted is photoelectrically detected, and digital image signals are thereby obtained, which are to be used for compensating for nonuniformity in how the radiation is irradiated to the stimulable phosphor sheets.

Abstract: A radiation image diagnostic apparatus comprises a reader for obtaining a radiation image signal representing a radiation image of an object from a recording medium, an ID information input device for entry of ID information on the object, and a storage device for storing past radiation image signals and ID information corresponding thereto. A retrieval device retrieves a radiation image signal for comparison, which is of the same object as the object of the radiation image signal related to diagnosis obtained by the reader and which has been obtained prior to the radiation image signal related to diagnosis, from the past radiation image signals stored in the storage device based on the ID information entered from the ID information input device.

Abstract: In a temporal subtraction processing conducted by use of stimulable phosphor sheets, the difference between maximum transmitting radiation amount of digital image signals detected from the stimulable phosphor sheets carrying radiation images stored therein is calculated. The difference is added to a difference signal obtained by the subtraction processing prior to a gradation processing, or a gradation conversion table is shifted by the difference towards the high density side along the input signal coordinate axis. Or, read-out conditions in final read-out are adjusted so that the difference is eliminated. Or, a maximum frequency point signal is calculated from a histogram of the difference signal, the difference between a signal representing the standard background density of a subtraction image and the maximum frequency point signal is calculated, and correction is made so that the background density in the subtraction image becomes always the same.

Abstract: A radiation image is processed in a radiation image read-out and reproducing system wherein a read-out operation is carried out in which a stimulable phosphor sheet having a radiation image stored thereon is exposed to stimulating rays, which cause the stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon during exposure to radiation, and wherein the emitted light is photoelectrically detected and a read-out image signal which represent the radiation image is thereby obtained, said read-out image signal being used to reproduce the radiation image as a visible image. A radiation image processing method comprises the steps of calculating characteristic values, which serve as tools in the extraction of only those image signal components related to a diagnosis, or the like, from the read-out image signal, and carrying out transformation processing on the read-out image signal, the exact nature of the transformation depending on the characteristic values.

Abstract: In an energy subtraction processing for radiation images, a plurality of stimulable phosphor sheets laid one upon the other are simultaneously exposed to a radiation of high energy passing through an object, and then a different stimulable phosphor sheet is exposed to a radiation of low energy passing through the same object. Digital image signals detected from the stimulable phosphor sheets exposed to the high energy radiation are weighted and subjected to arithmetic averaging. A subtraction processing is carried out between an image signal obtained by the arithmetic averaging and an image signal detected from the stimulable phosphor sheet exposed to the low energy radiation.

Abstract: In an energy subtraction processing for radiation images conducted by use of stimulable phosphor sheets, a characteristic value of a difference signal obtained by a subtraction processing of digital image signals detected from the stimulable phosphor sheets carrying radiation images stored therein is calculated. When the difference signal is subjected to a gradation processing, the characteristic value is made to correspond to a predetermined density of a reproduced image by uniformly converting the difference signal or by correcting a gradation conversion table used for the gradation processing.

Abstract: In a method of adjusting image processing conditions for use in processing of final read-out image signals obtained by final read-out carried out for detecting the image signals used in reproduction of a visible image from a recording medium carrying a radiation image recorded thereon by limitation of an irradiation field, a histogram of the final read-out image signals obtained by the final read-out is created. Prospective edge point signals which are considered to be signals representing edge portions of the irradiation field are detected from the final read-out image signals. A region of a lever lower than the level of a characteristic value representing the prospective edge point signals is removed from the histogram, and the image processing conditions are adjusted on the basis of the histogram outside of the lower level region.

Abstract: In a method of recognizing an irradiation field, image signals at respective positions on a recording medium are detected based on image information detected from the recording medium, and X and Y axis are set along two adjacent sides of a contour of a rectangular irradiation field on the recording medium. The image signals are added up in the X and Y axis directions respectively, and Y axis positions at which levels of added-up signals in the X axis direction are equal to a threshold value and X axis positions at which levels of added-up signals in the Y axis direction are equal to the threshold value are detected. A region surrounded by straight lines passing through these positions along the X and Y axes is recognized as the irradiation field. In the method of adjusting image processing conditions, the image processing conditions are adjusted based on the image information inside of the irradiation field thus recognized.

Abstract: A radiation image which has been recorded on a recording medium is read out at predetermined sampling intervals in order to obtain an image signal. A method for generating a radiation image signal comprises the steps of, in the course of the radiation image being read out, first applying sampling intervals corresponding to a second spatial frequency fsw higher than a first spatial frequency fss, which is the maximum of a desired spatial frequency range, along at least one direction on the recording medium in order to obtain an original image signal. The original image signal is then subjected to filtering processing in order to transmit spatial frequency components below the first spatial frequency fss, and to reduce or eliminate spatial frequency components above the first spatial frequency fss. Lastly, the original image signal which has been obtained from the filtering processing is sampled at sampling intervals corresponding to the first spatial frequency fss in order to obtain an image signal.

Abstract: A method of recognizing (distinguishing) a radiation field is provided for radiation image recording and reproducing systems that utilize stimulable phosphor sheets. With respect to the process of reproducing radiation image information stored on the phosphor sheet by scanning it with stimulating rays, such as laser light, the present method allows the radiation field on the sheet to be precisely distinguished, reducing the influence of undesirable stored image energy emissions from outside the prescribed region. This enables radiation images to be obtained that are more effective for diagnostic purposes. The method can also be applied for the recognition of irregularly shaped radiation fields, which hitherto has been extremely difficult.

Abstract: A radiation image read-out apparatus comprises a read-out device for detecting a radiation image recorded on a recording medium and generating an electric image signal, an input device for entering information concerning the image recording portion of an object and the image recording method, and a control device for adjusting read-out conditions on the basis of the information entered by the input device and feeding the adjusted read-out conditions to the read-out device. A reproduction condition designating apparatus is constituted by the input device, the control device, a device for displaying the reproduction conditions adjusted by the control device, and a correction input device for correcting the reproduction conditions displayed by the display device.

Abstract: In a method of reading out a radiation image stored in a stimulable phosphor sheet, preliminary read-out for approximately detecting the image is conducted. A cumulative histogram of the image information is created, read-out conditions in the final read-out are corrected based on a characteristic value of the cumulative histogram, then the final read-out is conducted using the corrected conditions. Alternatively, a standard image information range is determined from the characteristic value, and the read-out conditions are adjusted so that the standard range corresponds to a predetermined electronic signal range. In addition, in the read-out method where gradation processing is performed for electronic image signals obtained by photoelectrically detecting the phosphor light emitted by the sheet, histogram of the image signals is created, and a desired image signal range is determined therefrom.

Abstract: A distribution of an image signal read from a stimulable phosphor sheet and bearing a transmitted radiation image of a human body is determined along a horizontal direction across the image. Signal values of the distribution along the direction are accumulated, and the rate of change of the accumulated values is determined to find the imaged posture of the image. Alternatively, the separation or the average value of the distribution is determined, or the pattern of the distribution is compared with a plurality of reference signal distribution patterns. The derivative of second order of a function approximated by the distribution pattern may be checked for its sign, or the distribution pattern may be checked to determine whether it is of a one-valley form or a two-valley form.