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: Original image signal components representing an image are subjected to component number decreasing processing wherein, along each of block lines which are set in parallel on an image, blocks each comprising a single picture element in the image are set at predetermined intervals, or blocks each comprising several picture elements are set continuously or at predetermined intervals, such that the phases of the blocks located along a block line are shifted from the phases of the blocks located along a neighboring block line. Only the respresentative image signal components determined from the image signal components representing the picture elements in the respective blocks are sampled as new image signal components. The new image signal components are classified into main components, which have been sampled at appropriate sampling intervals, and interpolated components other than the main components.

Abstract: Image signals are subjected to a first signal compression processing which is carried out with a small factor of compression. The compressed image signals, which are obtained from the first signal compression processing, are recorded on a first recording medium. When a predetermined period has elapsed after a compressed image signal obtained from the first signal compression processing was recorded on the first recording medium, or when the frequency with which the compressed image signal is read from the first recording medium has become lower than a predetermined value, the compressed image signal is read out from the first recording medium. The image signal, which has been read out from the first recording medium, is subjected to a second signal compression processing which is carried out with a large factor of compression. The compressed image signal, which is obtained from the second signal compression processing, is recorded on a second recording medium.

Abstract: A method of adjusting a read-out condition and/or an image processing condition for a radiation image comprises the steps of carrying out preliminary read out prior to carrying out final read out for obtaining an image signal which represents a radiation image stored on a stimulable phosphor sheet and which is to be used for reproducing a visible radiation image, and creating a histogram of a preliminary read-out image signal obtained by the preliminary read out. An image information range, which is necessary for reproducing the visible radiation image, is determined from the histogram. A read-out condition and/or an image processing condition is adjusted in accordance with a latitude of the image information range so that a latitude of the reproduced visible image is changed so as to widen nonlinearly when the latitude of the image information range widens.

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 a method of recognizing an irradiation field on a recording region of a recording medium on which one or more radiation image is recorded by limitation of the irradiation field, the recording region is divided into a plurality of small regions and the irradiation field is recognized for each of the small regions on the basis of image signals corresponding to the small region.

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: A method for generating a radiation image signal comprises the steps of detecting an image signal by reading out a radiation image, which has been recorded on a recording medium during an image recording operation using a grid and which comprises an object image and a striped grid image corresponding to the grid and superposed upon the object image. The image signal is sampled such that a plurality of image signal components are obtained which correspond to a plurality of discrete points on the radiation image, intervals between the discrete points varying irregularly from predetermined intervals at least along a direction intersecting the striped pattern of the grid image on the radiation image.

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: A radiation image read-out apparatus comprises a read-out component, an image processing component, and a menu item display and selection component.

Abstract: In a radiation image recording and reproducing system for recording a radiation image of an object on a recording medium, obtaining an image signal by reading out the radiation image and sampling the image information read out, carrying out image processing of the image signal, and reproducing a visible image from the processed image signal, a radiation image read-out method comprises the steps of changing the sampling density in accordance with characteristics of the recorded radiation iamge. A radiation image processing method comprises the steps of changing the magnification of the visible image in accordance with characteristics of the recorded radiation image. A radiation image reproducing method comprises the steps of changing the reproducing density, the number of visible images reproduced on a single recording sheet or the number of recoridng sheets, on which the visible image reproduced, in accordance with characteristics of the recorded radiation image.

Abstract: A stimulable phosphor sheet bearing radiation image information recorded thereon by limitation of the irradiation field is exposed to stimulating rays and light emitted by the stimulable phosphor sheet upon stimulation is photoelectrically read out to obtain image signals representing the radiation image information borne by the stimulable phosphor sheet. The irradiation field is recognized by obtaining digital image data for a plurality of positions on the stimulable phorphor sheet from the image signals, detecting prospective edge points, which are considered to be edge portions of the irradiation field on the stimulable phosphor sheet, on the basis of the image data of positions radially outwardly arranged in a plurality of directions from a predetermined point inside the irradiation field, and recognizing as the irradiation field the region surrounded by the lines passing through the prospective edge points.

Abstract: A method for recognizing the layout pattern of radiation images comprises the steps of preparing two-valued masks, each composed of a two-valued signal representing a layout pattern for radiation images which are to be stored on a stimulable phosphor sheet, and obtaining a preliminary read-out image signal by carrying out preliminary read out on a stimulable phosphor sheet on which radiation images have been stored. The layout pattern of the radiation images is recognized by converting the preliminary read-out image signal into a two-valued image signal, calculating rating values, which represent the degree of pattern matching between the two-valued image signal and the two-valued masks, finding the highest rating value that represents the highest degree of pattern matching among the rating values, and comparing the highest rating value with a predetermined value representing a predetermined degree of pattern matching.

Abstract: A radiation image read-out apparatus comprises a preliminary read-out device, a final read-out device, an image processor, and a condition adjuster. The condition adjuster is constituted of an operating section for calculating, from a preliminary read-out image signal, read-out conditions to be used in obtaining a final read-out image signal and/or image processing conditions to be used in image processing of a final read-out image signal, and carrying out image reproduction operating processes based on the preliminary read-out image signal so as to display images which would be reproduced if the calculated read-out conditions and/or the calculated image processing conditions were used. One of the images displayed is designated, and the operating section feeds a read-out condition and/or an image processing condition, which corresponds to the designated image, into the final read-out device and/or the image processor.

Abstract: A radiation image recording and read-out apparatus comprises an endless belt provided with a stimulable phosphor layer, a conveyance system for conveying the endless belt, an image recording section facing the endless belt for exposing the stimulable phosphor layer to radiation carrying an image to have the radiation image stored thereon, and an image read-out section facing the endless belt for irradiating stimulating rays to the image-recorded stimulable phosphor layer and obtaining electric image signals by detecting light emitted by the stimulable phosphor layer in proportion to the stored radiation energy when the stimulable phosphor layer is exposed to the stimulating rays. An erasing section faces the endless belt for eliminating residual radiation energy on the stimulable phosphor layer. The conveyance system is provided with adjustment section at least at two positions for variably adjusting a length of conveyance of the endless belt.

Abstract: A method of compressing radiation image signals by conducting redundancy suppression encoding processing of original image signals representing a radiation image comprises the steps of conducting pre-processing for decreasing the number of image signals of the original image signals by an appropriate method, and subjecting the image signals obtained by the pre-processing to the redundancy suppression encoding processing.

Abstract: An image enlarging or contracting method comprises the steps of obtaining groups of interpolated image signal components along every array of original picture elements so that the interpolated picture elements corresponding to the interpolated image signal components of each group are deviated in position in a predetermined direction from the interpolated picture elements corresponding to the interpolated image signal components of every other group. A mean value of the values of the interpolated image signal components corresponding to a set of the interpolated picture elements, which belong to different groups of the interpolated image signal components and which correspond to one another, is calculated. The calculation of the mean value is repeated for every other set of the interpolated picture elements, thereby to ultimately obtain a group of the interpolated image signal components, which are to be used for image enlargement or contraction, along every array of the original picture elements.

Abstract: A radiation image read-out apparatus comprises a preliminary read-out device, a final read-out device, an image processor, and a condition adjuster. The condition adjuster is constituted of an operating section for calculating, from a preliminary read-out image signal, a read-out condition for use in obtaining a final read-out image signal and/or an image processing condition for use in image processing of a final read-out image signal. A judging section judges the reliability of the read-out condition and/or the image processing condition calculated by the operating section. A displaying section indicates low reliability in cases where the judging section judges that the reliability of the read-out condition and/or image processing condition is low.

Abstract: An apparatus for photoelectrically detecting a radiation image of an object stored on a stimulable phosphor sheet by exposure to a radiation passing through the object and storing detected image signals comprises a circuit for recognizing an irradiation field on the stimulable phosphor sheet, and an image signal selection circuit for receiving irradiation field information generated by the irradiation field recognition circuit and selecting only the image signals inside of the irradiation field from the read-out image signals. Or, the apparatus comprises a section for creating a histogram of the read-out image signals, a histogram analysis section for determining a range of the read-out image signals outside of a peak region arising in the vicinity of the maximum signal value or the minimum signal value in the histogram, and an image signal selection circuit for receiving the output of the histogram analysis section and selecting only the image signals within the range from the read-out image signals.

Abstract: A high-speed image recording apparatus comprises a sheet changer for changing a stimulable phosphor sheet at an image recording position, a radiation source drive controller, and a filter changer for changing a radiation filter on a radiation passage between a radiation source and a stimulable phosphor sheet at each image recording step. The sheet changer, the radiation source drive controller and the filter changer are activated by signals sent from a controller to load the stimulable phosphor sheet to the image recording position, to change over the radiation filter, and then to emit radiation to the stimulable phosphor sheet via an object, thereby recording a high energy image and a low energy image of good energy discrimination in stimulable phosphor sheets.