Image analysis – Applications – Biomedical applications
Reexamination Certificate
2000-08-02
2004-09-21
Au, Amelia M. (Department: 2624)
Image analysis
Applications
Biomedical applications
C382S254000, C382S312000
Reexamination Certificate
active
06795572
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the processing of image data obtained, for example, by X-ray imaging.
2. Related Background Art
For X-ray image sensing for medical diagnosis, there has conventionally been employed a film-screen system in which a fluorescent screen and an X-ray photographic film are combined. In this method, X-rays being transmitted through an object are amplified according to the intensity thereof by the fluorescent screen and irradiate the X-ray photographic film, thereby forming an X-ray image showing information of the interior of the object.
Recently there has been introduced a digital X-ray image sensing apparatus in which X-rays converted by a fluorescent substance into visible light proportional to the intensity thereof, and such visible light is converted by a photoelectric converting element into an electrical signal and further converted into a digital signal by an A/D converter. For such photoelectric converting element there is being used amorphous silicon, which, in comparison with the digital X-ray image sensing apparatus utilizing the conventional image intensifier, allows one to form a large, thin and light sensor unit, and thereby an image sensing mode as in the conventional film-screen system is made possible.
Also, in the conventional X-ray image sensing room, the equipment includes a Bucky unit for mounting a cassette containing the film and the screen. Such a unit is available in a stand type for sensing the X-ray image of the patient in the standing position and a table type for sensing the X-ray image of the patient in the lying position, and plural units are often provided in a single X-ray image sensing room.
Also, the X-ray image sensing room is often equipped with plural X-ray generating bulbs, but only one of such plural sensor units is used for irradiation since only one patient at a time is subjected to image sensing.
In such digital X-ray image sensing systems, it is required to use a control unit and an operation unit in common and to execute the image sensing by switching between the plural sensor units.
On the other hand, the X-ray sensor unit of a cassette type can be carried manually and connected to various control portions, so that an X-ray sensor unit can be used in turn in different X-ray image sensing rooms.
However, each X-ray sensor unit has its own characteristics for the digital image sensing.
For example, the solid-state image pickup device in the X-ray sensor unit usually has 2700×2700 pixels, and certain defects in such pixels are inevitable. For this reason the pixel defect information, indicating the defective pixels, is important and the image has to be corrected according to such information before being used for diagnosis.
Also, as the sensitivity characteristics are different from pixel to pixel, the charge amount accumulated for a same amount of light fluctuates. Such fluctuation is corrected by gain correction, which is executed according to a correction table indicating the normalized output under the uniform irradiation of X-rays. The image sensing for preparing such gain correction table is called calibration imaging.
Also, in each X-ray sensor unit, the correcting conditions vary according to the image sensing method because the detachable grid, the fluorescent substance, the phototimer, etc., are changed, so that the correction process in the control unit also varies. The information of these conditions has to be entered into the control unit each time the digital X-ray sensor unit connected to the control unit is changed, and the calibration imaging has to be conducted each time. These operations are very cumbersome to the user. Also, the calibration imaging may become necessary in the course of the X-ray image sensing operation, and the waiting time of the patient becomes very long in such case.
SUMMARY OF THE INVENTION
The object of the present invention is to execute optimum image processing according to the sensor unit.
The above-mentioned object can be attained, according to aspect of the present invention, by providing an image processing apparatus that has an X-ray irradiation unit which irradiates X-rays, one or more X-ray sensor units each of which includes an X-ray sensor which converts the X-rays into an electric signal, selection means for selecting the X-ray sensor units, information obtaining means for obtaining information for a sensing environment, memory means for storing correction data corresponding to the information for the sensing environment, and correction means for correcting outputs of the X-ray sensor units using the correction data corresponding to the information obtained by the information obtaining means. In a case in which the memory means does not contain correction data corresponding to the information obtained by the information obtaining means, the correction means selects the correction data from among the correction data stored in the memory means, on the basis of one of either a serial number of the X-ray sensor or a lot number of the X-ray sensor, to effect the correction using the selected correction data.
According to another aspect of the present invention, there is also provided a control method for an image processing apparatus including memory means storing plural correction data respectively corresponding to plural sensor units, each containing a sensor for sensing the image of an object, the method including selecting the X-ray sensor units, obtaining the information for the sensing environment, and in a case in which the memory means does not contain correction data corresponding to the obtained information, selecting from among the correction data stored in the memory means, either a serial number of the X-ray sensor or a lot number of the X-ray sensor, to effect correction using the selected correction data.
According to another aspect of the present invention, there are also provided a memory medium storing a program for controlling an image processing apparatus according to the mentioned method, and a program for performing such control.
Other objects of the present invention, and the features thereof, will become fully apparent from the following description which is to be taken in conjunction with the accompanying drawings. Moreover, while additional features of the present invention are disclosed herein, the present inventor does not waive any portion of what he has disclosed.
REFERENCES:
patent: 4916640 (1990-04-01), Gasperi et al.
patent: 5400792 (1995-03-01), Hoebel et al.
patent: 5606632 (1997-02-01), Matsumoto et al.
patent: 5644610 (1997-07-01), Crawford et al.
Au Amelia M.
LaRose Colin
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