Abstract: In a method for the operation of a medical X-ray installation having at least one C-arm at which a solid-state image detector is rotatably arranged and also having a control device that controls the operation thereof, whereby the control device determines an arbitrary position for the solid-state image detector relative to the C-arm, for positioning the solid-state image detector, at which the collision risk of the solid-state image detector with an object is lowest; and the image is computationally rotated dependent on the position data of the solid-state image detector after the image exposure in order to enable a perpendicular presentation of the examination region at an output medium.

Abstract: A X-ray image radiographing system, comprises a plurality of X-ray image output apparatus each of which detects X-rays having passed through an object and outputs image data of the object; a control apparatus to control the plurality of the X-ray image output apparatus; an object information input device to input object information regarding the radiographed object; and a storage device to store the image data outputted from the plurality of X-ray image output apparatus and the object information inputted from the object information input device, wherein the image data of the object is stored so as to be correlated with the object information of the object.

Abstract: A computed tomography apparatus has a gantry with an X-ray source and an x-ray detector, and at least one further, curved solid-state radiation detector that is movable into and out of the beam path of the x-ray source is provided in the gantry.

Abstract: A radiation image sensor comprises (1) an image sensor 1 having a plurality of light receiving elements arranged in one or two dimensionally, (2) scintillator 2 having columnar structure formed on the light-receiving surface of this image sensor 1 to convert radiation into light that can be detected by the image sensor 1, (3) a protective film 3 formed so as to cover and adhere to columnar structure of scintillator 2, (4) a frame 6 disposed around the scintillator to set separation distance from the scintillator and fix the protective film onto the image sensor, and (5) a radiation-transmittable plate 4 fixed opposite to the image sensor 1 by the frame 6 to sandwich the protective film 3 therebetween.

Abstract: An apparatus and method used in intra-oral dental x-ray imaging equipment provides automatic detection of the x-ray emission in order to obtain timely transition to the image integration and acquisition phase with high level of rejection of false triggering induced by blemish defects of the image sensor or by variations of the ambient and temperature conditions. A solid state imager, such as a CCD image sensor, is continually clocked during the standby phase prior to irradiation from an X-ray source, so providing on same time an output signal proportional to the accumulated dark current and the continuous removal of the same. A control unit analyses the output signal of the imager, detects the variation caused by the start of the x-ray emission using appropriate threshold levels, and automatically triggers the imager to the image integration and acquisition phases.

Abstract: A radiation detecting apparatus has a conversion element having a semiconductor layer for directly converting a radiation into a charge; and a variable voltage source for applying an electric field to the semiconductor layer, wherein the variable voltage source applies a voltage of a plurality of values as to apply at least electric fields in an identical direction and in different strengths.

Abstract: A system for spectroscopic imaging of bodily tissue in which a scintillation screen and a charged coupled device (CCD) are used to accurately image selected tissue. An x-ray source generates x-rays which pass through a region of a subject's body, forming an x-ray image which reaches the scintillation screen. The scintillation screen reradiates a apatial intensity pattern corresponding to the image, the pattern being detected by a CCD sensor. The image is digitized by the sensor and processed by a controller before being stored as an electronic image. Each image is directed onto an associated respective CCD or amorphous silicon detector to generate individual electronic representations of the separate images.

Abstract: The present invention discloses a method of aligning scintillator crystalline structures for computed tomography imaging and a system of use. Crystal seeds are deposited inside a glass melt and are then grown to form a plurality of layer crystallites. While growing the crystallites, a field is applied to align each crystallite structure in a uniform orientation. As a result, the crystallites are configured to reduce light scattering and improve the overall efficiency of the CT system. A CT system is disclosed implementing a scintillator array having a plurality of scintillators, each scintillator being formed of a plurality of uniformly aligned crystallites. Each crystallite includes a receiving surface and an exiting surface configured perpendicular to an x-ray beam. Further, the receiving surface and the exiting surface are connected by a plurality of surface walls arranged parallel to the x-ray beam.

Abstract: A technique for generating replacement values for defective pixels in a digital imaging system includes generating a base values for the defective pixels and a statistical characterizing values which provide consistent statistical relationships with other pixels. The base values may be computed as mean values of pixels surrounding the defective pixels. The statistical characterizing values may be selected to provide deviation from the mean values by a standard deviation of other selected pixels, such as pixels in the neighborhoods of the defective pixels. The technique avoids image artifacts due to inconsistent noise or other statistical characteristics in the pixel replacement values.

Abstract: A solid-state radiation detector is provided comprising a carrier, a pixel matrix arranged carrier-proximate and a scintillator arranged matrix-proximate for the conversion of the incident radiation into a radiation that can be processed by the pixel matrix. A low-absorption carrier is provided that is arranged at the beam entry side of the solid-state radiation detector.

Abstract: An image pickup device is provided that comprises: a photoelectric conversion region; a driving circuit for reading out a signal generated by photoelectric conversion from an identical pixel contained in the photoelectric conversion region for a plurality of times; and a correction circuit for extracting a noise component by calculating a difference among a plurality of signals read out by the driving circuit and removing the noise component contained in the signals from the pixel using the extracted noise component.

Abstract: A method for acquiring a radiographic image of an elongated object, comprising: positioning an elongated object between a source of x-rays and a digital image capture device having an imaging dimension which is less than a like dimension of said elongated object; wherein said image source is stationary and said source projects an x-ray pattern which encompasses said elongated object; moving said digital image capture device in a direction parallel to said known imaging dimension to sequential contiguous stationary positions to acquire a sequence of radiographic images of said elongated object; and moving an assembly of x-ray opaque material which is positioned between said source of x-rays and said elongated object, and which has an opening for allowing passage of x-rays, such that said opening is synchronized with the movement of said digital image capture device to facilitate acquisition of said sequence of radiographic images at said stationary positions.

Abstract: Since the duration of an idling drive period is not defined (not specified) in practical use, T1 is set to be longer than that in a normal photographing operation to make idling-dedicated idle read frames Fi in which the ON time of a TFT (82) is shorter than the normal read drive frame, so as to minimize read operations that impose a heavy load on a photodetector array (58) (especially, the TFT (82)).

Abstract: An x-ray system (10) include a digital detector (400) that defines two regions: a first region (404) suitable for generating data useful for creating a patient x-ray image and a second region (406) less suitable for generating such data than the first region. A source (20) transmits x-rays through a phantom (420) located between the source and the second region (406) so that the detector (400) generates test data in the second region. A processor (302) measures at least one parameter in response to the test data and stores a value of the parameter at one point of time. The processor compares the first value with a second value of the one parameter generated at a later second point in time. The processor also generates a result signal representing the results of the comparison.

Abstract: A real time data acquisition system includes a personal computer and a detector framing node cooperating to control generation of radiation and control radiographic detection. Data is acquired by a detector framing node and communicated independently of a non-real time operating system running on a host computer. The detector framing node controls events in real time according to an event instruction sequence and communicates received radioscopic data to a host memory. Data is received from a selected flat panel detector of a plurality of different flat panel detectors. The data is received as single frames or continuous frames before communication to the host memory.

Abstract: An x-ray system (10) include a digital detector (400) that defines two regions: a first region (404) suitable for generating data useful for creating a patient x-ray image and a second region (406) less suitable for generating such data than the first region. A source (20) transmits x-rays through a phantom (420) located between the source and the second region (406) so that the detector (400) generates test data in the second region. A processor (302) measures at least one parameter in response to the test data and stores a value of the parameter at one point of time. The processor compares the first value with a second value of the one parameter generated at a later second point in time. The processor also generates a result signal representing the results of the comparison.

Abstract: An image detector monitoring system includes a detector framing node and a host computer having at least one host processor and a host memory. The detector framing node acquires image data, buffers the acquired image data, and outputs the image data to the host memory according to a predetermined communication protocol. The host computer executes operations according to a non-real time operating system, and a host memory stores the image data received from the detector framing node. The detector framing node is controlled by executing a plurality of event instructions, which are stored in an event queue. Some event instructions control a radiation generation system, while others control communication with an image detection system or control the detector framing node itself. Each event instruction executed by the detector framing node includes a bit flag indicating whether the event is to be traced by the detector framing node. Traced events are stored as entries in a response log in host memory.

Abstract: The present invention provides a detector for a multi-slice CT system. The detector includes a scintillator for receiving and converting high frequency electromagnetic energy directly to electrons. The detector is further configured to directly conduct the electrons. The detector comprises a compound formed of scintillator bulk and a conducting material capable of converting high frequency energy to electrons as well as conduct electrons. The CT system also provides for a gantry having an output for projecting high frequency electromagnetic energy toward the detector and a data acquisition system for receiving electrons directly from the detector. A method to provide imaging electrons to a CT system is also provided.

Abstract: In order to realize a photoelectric conversion apparatus capable of easily switching a mode requiring a wide dynamic range in obtaining a motion image and a mode requiring a reduction in noise in obtaining a still image, a mode switching means is used, when a refresh operation is performed for each photoelectric conversion element, to switch between a mode of setting the potential of one electrode of the photoelectric conversion element to be higher than the potential of the other electrode, and a mode of setting the potential of one electrode of the photoelectric conversion element to be lower than the potential of the other electrode, thereby arbitrarily changing the refresh voltage. With this operation, desired photoelectric conversion signals for a motion image and a still image can be obtained.

Abstract: A method for acquiring an elongated radiographic image comprising: positioning an elongated object between a source of x-rays and a digital image capture device having a known imaging dimension which is less than a like dimension of said elongated object; moving said device in a direction parallel to said known imaging dimension to sequential contiguous positions to acquire a sequence of radiographic images of said elongated object; and rotating said source of x-rays about an axis perpendicular to said direction of moving said device in coordination with said moving project said x-rays from said source toward said device.

Abstract: A radiation imaging apparatus includes a plurality of spaced apart imaging elements comprising each a plurality of pixels and an external terminal for external connection, wherein a lead constituting the external terminal is extended to the side portion opposite to a light receiving surface of each of the spaced apart imaging elements through a space between the adjacent imaging elements, a first planarizing layer is formed on the light receiving surface to be positioned at the same height as the external terminal or on the incidence side based on the height of the light receiving surface, and a wavelength converter is formed on the plurality of spaced apart imaging elements through a second planarizing layer formed on the external terminal and the first planarizing layer.

Abstract: A holder for a dental X-ray image sensor is provided which enables adjustment of the position of the sensor after placement of the holder and sensor in the mouth. A flexible, deformable or elastic loop holds the sensor in place but enables manipulation of the sensor position. The elastic loop is connected to a handle member. A slot also is provided in the handle for accommodating wire leads connected to the sensor.

Abstract: An automatic exposure control for an x-ray system using a large area solid state x-ray detector (26) includes an exposure control (36, 34) arranged to generate data of interest within the data generated by the detector and to adjust the dosage of x-rays to a predetermined level in response to data of interest so that an x-ray image of a patient is generated using the predetermined level.

Abstract: Driving an X-ray imaging device by applying a high voltage signal to a photo-sensing layer, reading the stored charges that result from dark charges produced by the high voltage signal using a data reader such that stored charges are removed from the charging capacitors, performing X-ray irradiation such that X-ray induced charges are stored in a charging capacitor, and converting the stored charges to electrical signals, all while maintaining the high voltage on the photo-sensing layer. The driving method improves a contrast ratio caused by the dark charges and reduces signal variations caused by turning-off the high voltage before converting the stored charge into electrical signals. As the high voltage turned on and off only one once the driving time can be reduced.

Abstract: The motion picture quality of liquid crystal display apparatus is improved by placing a non-display period depending on the responsiveness of the liquid crystal and a backlight source. For this purpose, a sub-period is set, within one frame period, for displaying a luminance corresponding to prescribed picture data so as to provide a time integral of luminance corresponding to a maximum luminance not exceeding a certain threshold, and another sub-period for displaying a lower luminance is placed in the same one frame period.

Abstract: The invention relates to a detector for the detection of electromagnetic radiation (6, 9), including scintillators (S1-S5), a photosensor device (F1-F5) and an intermediate layer (10). The optical crosstalk due to multiple reflection in the intermediate layer is prevented in that at least parts of the intermediate layer (10) contain substances absorbing electromagnetic radiation (9).

Abstract: The invention is related to an X-ray image sensory system, including an electrode layer, a conversion layer, a gap layer and a charge collection layer. The system utilizes the “X-ray→charge” conversion layer, and operates in an electrical field to enable the “X-ray→charge→field emission electron” mechanism. The mechanism makes the field emission electrons move from the conversion layer, across the gap layer, and towards the charge collection layer. The charge collection layer is made of specific kinds of semiconductor materials. Based on the amount of the charges collected at the charge collection layer, the system is able to determine the amount of the X-ray initially emitted into the conversion layer.

Abstract: A semiconductor radiation imaging device is disclosed which includes an array of image elements, each image element of said array comprising an image element detector cell which generates charge in response to radiation incident on said image element and image element circuitry for accumulating said charge from said image element detector cell and for selectively outputting a signal representative of accumulated charge. The imaging device further includes a radiation sensor element, said radiation sensor element comprising a radiation detector cell integral with said image element detector cells for generating charge in response to incident radiation on said radiation sensor element and a radiation sensor output for continuously supplying charge from said radiation detector cell. Also disclosed is an imaging system employing image devices as described above, and a method of imaging radiation.

Abstract: A system for spectroscopic imaging of bodily tissue in which a scintillation screen and a charged coupled device (CCD) are used to accurately image selected tissue. An x-ray source generates x-rays which pass through a region of a subject's body, forming an x-ray image which reaches the scintillation screen. The scintillation screen reradiates a spatial intensity pattern corresponding to the image, the pattern being detected by a CCD sensor. The image is digitized by the sensor and processed by a controller before being stored as an electronic image. Each image is directed onto an associated respective CCD or amorphous silicon detector to generate individual electronic representations of the separate images.

Abstract: The detector materials (8, 9) of a low energy detector (5) and a high energy detector (6) are coordinated with one another to permit better separation of lower and higher energy fractions of polychromatic X-ray (X′) radiation, and consequently, create a better determination of a material of an object through which the X-rays are passed. Thus, a negligible persistence in comparison with the integration time between two detector readings is achieved.

Abstract: The invention relates to an X-ray system which includes an X-ray source and an X-ray detector for deriving an image signal. The X-ray detector includes an X-ray matrix sensor, such as an FDXD, which includes a matrix of sensor elements. Preferably, the sensor elements are light-sensitive &agr;-Si sensor elements (photodiodes) and the FDXD is provided with a scintillator layer which converts X-rays into light. The sensor elements generate electric charges that are read out in the form of an image signal that represents the X-ray image. The X-ray matrix sensor is provided with an additional array of detection elements which are arranged between the sensor elements and the X-ray source. More specifically, the detection elements are also &agr;-Si light-sensitive photodiodes. The scintillator layer is arranged between the X-ray matrix sensor and the additional array of detector elements. A partly transparent coating is disposed between the additional array of detector elements and the scintillator layer.

Abstract: A method is provided for determining source-to-image distance (SID) setpoints in a digital imaging system. SID setpoints are determined during a setup and calibration procedure which includes generating radiation beams while varying certain system parameters, such as the radiation source position, and detecting and determining the size of the radiation beams that impact on the digital detector. SID values and a separation gain constant can then be determined based on the calculated sizes of the detected radiation beams and the feedback signals which are representative of the various system parameters that were varied (e.g., source position, etc.) during the setup and calibration procedure. The separation gain constant and the calculated, empirical SID values can then be used to position the radiation source at any user-selected SID based on position sensor feedback signals. The procedure also provides for a calibrated readout of the SID, which can be displayed to a user of the imaging system.

Abstract: A radiation photographing apparatus has a radiation image receiving portion for receiving radiation transmitted through an object and obtaining a radiation transmission image, and a grid to be disposed on the object side of the radiation image receiving portion. The grid includes a scattered ray removing member or a radiation detector. The grid is constructed for movement also to the side opposite to the object side of the radiation image receiving portion.

Abstract: A CT scanner (10) includes a reconstruction processor (32) for reconstructing an image from digital signals from detector arrays (20). Each detector array includes scintillation crystals (22) arranged in an array for converting x-ray radiation into light. An array of back-illuminated photo diodes (24) is mounted beneath the scintillation crystal array for converting the light emitted from the scintillation crystals into electrical charge. The electrical charge from the back-illuminated photodiodes is transmitted via a path orthogonal to the detector array (20, 40) to signal processing circuitry (66). The back-illuminated photodiode has a backside (26) which is in optical communication with the crystal array (22) and which is optically transmissive to photons of light emanating from the crystal. The converted electrical charge leaves the photodiode via electrical connections (28) or bump bonds (62, 72) on the front side of the photodiode.

Abstract: In a method for determining row correction values for a digital image converter, with image points arranged in a matrix in rows and columns, in which a small part is protected against radiation by a covering, in order to form a dark reference zone, row correction values are formed by determining the differences of the image points in the dark reference zone in relation to their environment with defective pixels in the dark reference zone being determined and are suppressed in the determination of the row correction value.

Abstract: An automatic exposure control for an x-ray system using a large area solid state x-ray detector (26) includes an exposure control (36, 34) arranged to generate data of interest within the data generated by the detector and to adjust the dosage of x-rays to a predetermined level in response to data of interest so that an x-ray image of a patient is generated using the predetermined level.

Abstract: A technique is provided for increasing the pixel pitch without increasing the interconnect density of a digital detector. Generally, a digital detector has an array of rows and columns of pixels, read out electronics and scan electronics, that are configured to generate and transmit signals based upon radiation impacting the detector. The detector also having a plurality of scan lines, which are coupled to the plurality of rows of pixels. The present technique also provides a multiplexing circuit for selectively coupling the rows of pixels to the respective scan lines for read out of the signals.

Abstract: A technique for generating replacement values for defective pixels in a digital imaging system includes generating a base values for the defective pixels and a statistical characterizing values which provide consistent statistical relationships with other pixels. The base values may be computed as mean values of pixels surrounding the defective pixels. The statistical characterizing values may be selected to provide deviation from the mean values by a standard deviation of other selected pixels, such as pixels in the neighborhoods of the defective pixels. The technique avoids image artifacts due to inconsistent noise or other statistical characteristics in the pixel replacement values.

Abstract: A radiation image reading apparatus is provided which includes a semiconductor detector for converting radiation photons penetrated through a subject into electric signals to generate first radiation image information, and a processor for processing the first radiation image information. The processor processes the first radiation image information so that a modulation transfer function in a low density region is not higher than a modulation transfer function in a high density region, in order to generate second radiation image information. The semiconductor detector includes a substrate, a plurality of electrodes, capacitors, switching elements, a photoconductive layer and a surface electrode, which are fabricated on the substrate.

Abstract: In an X-ray imaging system comprising an X-ray source, a digital X-ray detector and a display device, an arrangement is provided for setting or establishing the dynamic range of the image at the display device. The detector is operated to provide a set of count values representing X-ray image data acquired by the detector from an object of imaging, and a set of standardized values, such as optical density values, is derived from the count values. The optical density values collectively define a range of optical density values, and the dynamic range of the display device is mapped thereto. The display device is enabled to present an image of the object which appears similar to or substantially the same as an image of the object presented by, for example, a specified analog X-ray film.

Abstract: An X-ray imaging system comprising an X-ray image sensor and an image capture controller is provided. The X-ray image sensor includes a sensor array comprising a plurality of CMOS active column sensors. The image capture controller communicates with the X-ray image sensor to read out pixel values from selected ones of the CMOS active column sensor elements. The image capture controller may randomly select reference pixels from the plurality of CMOS active column sensor elements, and compare a signal of the reference pixels to a predetermined level to determine a start of X-ray exposure. The image capture controller also may randomly select second reference pixels from the plurality of CMOS active column sensor elements, and monitor the second reference pixels to determine an end of X-ray exposure. The X-ray imaging system also may include a wireless interface for coupling the X-ray image sensor to the image capture controller. The X-ray imaging system may be used as a dental X-ray imaging system.

Abstract: A method and system for an automatic exposure control (AEC) arrangement for a matrix-addressed imaging panel having an array of sensors including use of localized regions of the imaging panel exhibiting capacitive coupling. In one embodiment, the matrix-addressed imaging panel includes one or more AEC electrode receptive field regions that provide a signal representative of exposure specific, respective AEC electrode receptive field regions. Additionally, in another embodiment, the imaging array includes data line signal monitoring regions in which capacitive coupling between electrodes in radiation sensors adjacent to the data line are read and processed to provide and AEC signal. In another embodiment, the imaging array includes both AEC electrode filed receptive regions and data line signal monitoring regions that are coupled to an AEC controller for control of the radiation source for the imaging array.

Abstract: A method is provided to identify pixels in a digital x-ray detector that experience an amount of residual charge that is sufficient to cause an image artifact. A lag artifact threshold is obtained. The lag artifact threshold identifies an amount of residual charge that, when held by the pixels in the digital x-ray detector, will cause image artifacts. A pixel lag experienced by a pixel is determined. The pixel lag may be different for each pixel. Pixels that have a pixel lag exceeding the lag artifact threshold are identified and corrected.

Abstract: An x-ray system (14) reads data from a detector array (22) including detector elements (40) arranged in rows (R1-R280) and columns (C1-C1365). A first group of rows include unneeded data (R1-R127) while a second group of rows include data of interest (R128-R1152). Activation of the detector elements in relation to the exposure of a patient to x-rays to improve efficiency with which the data of interest is read is disclosed. An exposure control (34) activates an x-ray tube (15) to expose the detector to x-rays during a first time period (E1). The first group of rows (R1-R127) are activated at least partially before or during the first time period. The second group of rows (R128-R1152) are activated after the first time period. Data is read from the second group of rows after the first time period.

Abstract: A preferred embodiment of the present invention provides a method and apparatus for correcting the offset induced by Field Effect Transistor (FET) photo-conductive effects in a solid state X-ray detector. The method and apparatus include reading out twice as many rows (scan lines) as actually exist in the X-ray detector. The additional rows may be read out between the actuation of “real” scan lines on the X-ray detector. The additional row times may be used to measure the “signal” induced by FET photo-conductivity. In a preferred embodiment, the “real” rows may be actuated during odd lines, and even lines will be used to measure the signal induced by FET photo-conductivity. To correct for the offset induced by photo-conductive FETs, an even row signal may be subtracted from the preceding odd row signal. The correction for the offset induced by photo-conductive FETs may occur in addition to normal offset correction.

Abstract: A radiation detector includes a plurality of detector modules detachably mounted on a detector base. Each of the detector modules has a plurality of element blocks permanently mounted on a module base. Each element block has a plurality of radiation detection elements formed on a signal substrate in the form of an m×n matrix. A detector module is made up of a plurality of element blocks. A radiation detector is made up of a plurality of detector modules. This makes it possible to tile many detection elements and manufacture a radiation detector with a wide field of view.

Abstract: A system for correcting exposure signals generated by a matrix-addressed x-ray imaging panel by compensating for amplifier offset and gain artifacts in integrating read-out amplifiers connected to a matrix-addressed array of photosensors in an imaging panel. An average amplifier offset is calculated in a sequence of operations tinder control of a scan line controller and is applied to the exposure signals during normal operation of the imaging panel. A base gain calibration image is obtained periodically and is updated on a real-time basis by a real-time gain determined optionally whenever exposure signals are generated during normal operation of the imaging panel. The resulting real-time adjusted gain calibration image is divided into the amplifier offset adjusted exposure signals on a pixel-by-pixel basis to yield an exposure signal compensated for offset and gain on a real-time basis.

Abstract: In an X-ray detection device having an X-ray detection element array of photo diodes for multi channels arranged with a predetermined pitch on a substrate, a plurality of scintillators adhered onto respective photo diodes, and isolation walls disposed between neighboring scintillators for respective channels an isolation band for isolating the respective channels is provided between respective light receiving portions of the photo diode array for the multi channels, and the surface of the isolation band is covered by a material having light absorbing property, and the width of the region which is covered by the material having light absorbing property is equal to a region occupied by the width of the isolation wall provided between neighboring scintillators for the respective channels.

Abstract: A method for minimizing motion artifacts in Dual Energy Subtraction digital radiographic imaging applications by minimizing the time lapse between the two x-ray exposure frames. This is accomplished by acquiring the two x-ray exposure frames relatively consecutively without a corresponding offset frame reading in-between the two x-ray frame exposures. Preferably, the offset frames are acquired following the x-ray exposure frames with a corresponding timing sequence which is correlated to the x-ray frame exposure and reading sequence.

Abstract: A color radiography system comprises a color light emission sheet having a phosphor layer that contains a phosphor emitting in a plurality of colors to radiation and emits light under irradiation of radiation transmitted through a subject to be inspected, and a color film or a color camera that detects the light emissions of the plurality of colors into the respective colors. In the phosphor layer, a phosphor is used that has a primary emission component corresponding to one emission color in a visible light region and at least one secondary emission component, the secondary emission component having an emission color different from that of the primary emission component and a ratio of light emission to radiation of the same intensity being different from that of the primary emission component. According to the present color radiography system, image information of a plurality of colors having different sensitivity characteristics can be obtained.