Shimadzu Corporation

Shoichi Okamura

Toshinori Yoshimuta

Koichi Tanabe

Susumu Adachi

Shinya Hirasawa

Keiichi Fujii

Akihiro Nishimura

Shigeya Asai

Kenji Kimura

Shigeki Kajihara

Masatomo Kaino

Akira Arakawa

Hiroshi Koyama

An image processing system of this invention includes a variation calculator for calculating a variation in pixel value of each pixel relative to adjacent pixels, and an edge degree calculating device for calculating, for one arbitrary pixel, an edge degree which expresses numerically a probability of the one pixel being an edge, based on variations of a peripheral pixel group consisting of the one pixel and surrounding pixels. According to the image processing system constructed in this way, whether edges or not can be evaluated with high accuracy even when the pixels undergoing noise.

Edge evaluation method, edge detection method, image correction method, and image processing system

A radiation image pickup device comprises temperature control means for maintaining the temperature of an X ray conversion layer to be substantially constant by performing a feedback process for controlling a voltage which is applied to the Peltier element based on the temperature of the X ray conversion layer. The temperature control means starts reading out an electric charge from each pixel (DU), then converts the electric discharge to voltage with a charge amplifier and in a period until an A/D conversion process for the voltage is completed, and restricts a variation in the voltage which is applied to the Peltier element.

Radiation image pickup device

A radiographic apparatus according to this invention stores, before an imaging event, offset images and gain correcting images corresponding to a plurality of storage times, and acquires a lag image and a radiographic image based on these stored images. Then, lag correction is carried out to remove lags, using the lag image, from the radiographic image. In this way, from the radiographic image taking into consideration the offset images and gain correcting images corresponding to the storage times, lags are removed using the lag image which similarly fakes into consideration the offset images and gain correcting images corresponding to the storage times. Lag-behind parts, including offset and gain components, are removed from radiation detection signals in a simple way.

Radiographic apparatus and radiation detection signal processing method

A radiographic apparatus according to this invention carries out lag correction by applying lag data based on a plurality of radiation detection signals acquired in time of non-irradiation before first irradiation, to both first and second radiation detection signals. Thus, lag correction is possible without acquiring lag components between the first irradiation and second irradiation. Also in the case of carrying out two radiation irradiations (first irradiation and second irradiation) for one image, lag-behind parts included in the radiation detection signals can be removed simply from the radiation detection signals.

A radiographic apparatus according to this invention, when carrying out recursive computation, pixel groups consisting of detection pixels respectively corresponding to positions on a radiation detection device are sorted into locations subjected to the recursive computation and locations exempted from the recursive computation. For the locations subjected to the recursive computation, lag-behind parts are removed by the recursive computation to obtain corrected radiation detection signals. The recursive computation is not carried out at least for the locations exempted from the recursive computation. The lag-behind parts can be removed from the radiation detection signals, with a calculation amount for the recursive computation reduced by an amount corresponding to the recursive computation excluded.

A radiographic apparatus according to this invention, when a predetermined operation relating to radiographic imaging is interposed during an emission of radiation, stops the emission temporarily, and also stops a recursive computation temporarily. With start of the predetermined operation, the emission is started again and also the recursive computation is started again. Radiation detection signals at the time of non-emission due to the temporary stop are acquired, and the recursive computation is carried out based on initial values derived from the radiation detection signals at the time of non-emission. The lag-behind parts are removed from the radiation detection signals with increased accuracy while reducing the trouble of radiographic images caused by the predetermined operation relating to radiographic imaging being interposed during an emission of radiation.

Corrected X-ray detection signals are obtained by removing lag-behind parts through a recursive computation based on initial values determined from lag signal value (step T). Thus, the lag-behind parts can be removed by taking into consideration lag signal values remaining at a starting point of the recursive computation. The lag signal values are dependent on the characteristic of an FPD (flat panel X-ray detector). By removing the lag-behind parts, with the lag signal values taken into consideration, the lag-behind parts are removed from X-ray detection signals with increased accuracy, without being influenced by the characteristic of the FPD.

A radiographic apparatus obtains lag-free radiation detection signals with lag-behind parts removed from radiation detection signals taken from a flat panel X-ray detector as X rays are emitted from an X-ray tube. The lag-behind parts are removed by a recursive computation on an assumption that the lag-behind part included in each X-ray detection signal is due to an impulse response formed of exponential functions, N in number, with different attenuation time constants. X-ray images are created from the lag-free radiation detection signals.

Radiographic apparatus that removes time lag by recursive computation

A radiographic apparatus removes lag-behind parts from radiation detection signals taken from an FPD as X rays are emitted from an X-ray tube, on an assumption that the lag-behind part included in each X-ray detection signal is due to an impulse response formed of a plurality of exponential functions with different attenuation time constants. When a single attenuation time constant and intensity are provisionally set, checking is made whether an attenuation to a noise level of X-ray detection signals occurs in an X-ray non-emission state following an X-ray emission state. When the set attenuation time constant and intensity are found appropriate (OK), the impulse response having the single exponential function is determined valid. Corrected radiation detection signals are obtained by removing the lag-behind parts using the impulse response determined.

In the radiographic apparatus according to this invention, when a radiographic mode designatordesignates a non-standard radiographic mode, a signal correctoruses defect information stored in one of non-standard image defect information memoriesB&#x2013;E for correcting X-ray detection signals outputted from an FPDSince the pixel defect information for non-standard X-ray images is acquired by a pixel defect information converterthrough a conversion from defect information for standard X-ray images stored in a standard image defect information memoryA, it is unnecessary to collect output signals for pixel defect information acquisition from the FPDall over again. As a result, abnormal X-ray detection signals due to defects of radiation detecting elements may be corrected promptly, regardless of how the radiation detecting elements are assigned to the pixels in the X-ray images.

Radiographic apparatus, and radiation detection signal processing method

An apparatus according to the invention includes a response coefficient to dose relationship memory for storing, in advance, a relationship of correspondence between intensities of an exponential function for impulse response and X-ray doses. The intensities of the exponential function determine conditions relating to an impulse response in a recursive computation performed to remove lag-behind parts from X-ray detection signals outputted from an FPD, thereby to obtain corrected X-ray detection signals. An impulse response coefficient setter sets an impulse response coefficient corresponding to an X-ray dose for an object under examination based on the relationship of correspondence between intensities of the exponential function and radiation doses. A time lag remover performs the recursive computation for time lag removal, with the intensity of an exponential function set to correspond to the X-ray dose for the object under examination. Thus, a lag-behind part is removed properly from each X-ray detection signal.

A radiographic apparatus removes lag-behind parts from radiation detection signals taken from an FPD as X rays are emitted from an X-ray tube, on an assumption that the lag-behind part included in each X-ray detection signal is due to an impulse response formed of exponential functions, N in number, with different attenuation time constants. The lag-behind parts are removed by using impulse responses corresponding to variations in the sensor temperature of the FPD. X-ray images are created from corrected radiation detection signals with the lag-behind parts removed therefrom.

Radiographic apparatus

A biomagnetism measuring method and apparatus for determining a positional relationship of an examinee with fluxmeters in a short time. A current supply unit simultaneously supplies alternating currents of different frequencies to a plurality of oscillator coils attached to the examinee, respectively. The fluxmeters detect magnetic fields simultaneously formed by the oscillator coils supplied with the currents. Field data thereby obtained are applied through a data collecting unit to a field analyzer for frequency analysis to recognize field strengths due to the respective oscillator coils for the respective fluxmeters. The field analyzer computes positions of the oscillator coils relative to the fluxmeters from the field strengths recognized for the respective oscillator coils and known values of the currents supplied to the respective oscillator coils. Based on this positional information, information indicative of positions of bioelectric current sources measured in a separate process is displayed as superposed on an MRI image of a site of interest of the examinee.

Growing community of inventors

Kyoto, Japan

Shoichi Okamura