Signal correcting method for radiation image read-out apparatuses
Light emitted by a stimulable phosphor sheet, on which a radiation image has been stored, is detected with a line sensor comprising line sensor constituting units arrayed such that their certain regions overlap each other. A test image, in which edge patterns are embedded at positions corresponding to the overlapping regions of the line sensor constituting units, is read out, and test image signal components are acquired from each of the line sensor constituting units. Position matching processing is performed on radiation image signal components of a radiation image signal representing the radiation image, which have been obtained from the line sensor constituting units, and in accordance with edge pattern signal components, which represent the edge patterns and are contained in the test image signal components.
1. A signal correcting method for use in a radiation image read-out apparatus, wherein position matching processing is performed on radiation image signal components of a radiation image signal representing a radiation image, which radiation image signal components have been obtained from a plurality of line sensor constituting units in the radiation image read-out apparatus comprising:
i) a line light source for linearly irradiating stimulating rays onto an area of one surface of a stimulable phosphor sheet, on which the radiation image has been stored, the stimulating rays causing the stimulable phosphor sheet to emit light in proportion to an amount of energy stored thereon during its exposure to radiation,
ii) a line sensor for receiving light, which is emitted from the linear area of the one surface of the stimulable phosphor sheet exposed to the linear stimulating rays or from a linear area of the other surface of the stimulable phosphor sheet corresponding to the linear area of the one surface of the stimulable phosphor sheet, and performing photoelectric conversion of the received light, the line sensor comprising the plurality of the line sensor constituting units, each of which comprises a plurality of photoelectric conversion devices arrayed along a length direction of the linear area of the stimulable phosphor sheet, the plurality of the line sensor constituting units being arrayed along the length direction of the linear area of the stimulable phosphor sheet such that certain regions of adjacent line sensor constituting units overlap each other,
iii) scanning means for moving the stimulable phosphor sheet with respect to the line light source and the line sensor and in a direction different from the length direction of the linear area of the stimulable phosphor sheet, and
iv) reading means for successively reading outputs of the line sensor in accordance with the movement in order to obtain the radiation image signal, which represents the radiation image,
the method comprising the steps of:
a) reading out a test image, in which edge patterns extending in a direction different from the length direction of the linear area of the stimulable phosphor sheet are embedded at positions corresponding to the overlapping regions of the line sensor constituting units, test image signal components of a test image signal, which represents the test image, being thereby acquired from each of the line sensor constituting units, and
b) performing the position matching processing on the radiation image signal components of the radiation image signal representing the radiation image, which radiation image signal components have been obtained from the plurality of the line sensor constituting units, and in accordance with edge pattern signal components, which represent the edge patterns embedded in the test image and are contained in the test image signal components of the test image signal representing the test image,
wherein the position matching processing provides position matched radiation image signal components, said position matched components become calculated to determine a mean or an interpolated value based on data corresponding to the overlapping regions of the line sensor.
2. A method as defined in claim 1 wherein the test image is formed on said stimulable phosphor sheet, and the test image signal is acquired by reading out the test image, which has been formed on said stimulable phosphor sheet.
3. A method as defined in claim 1 wherein the stimulable phosphor sheet, on which the radiation image has been stored, is provided with a region, in which the test image has been formed, the radiation image and the test image are read out from the stimulable phosphor sheet, and the radiation image signal and the test image signal are thereby obtained simultaneously.
4. The method of claim 1 , further comprising an image reading step separate from reading out the test image.
5. A signal correcting method for use in a radiation image read-out apparatus, wherein position matching processing is performed on radiation image signal components of a radiation image signal representing a radiation image, which radiation image signal components have been obtained from a plurality of line sensor constituting units in the radiation image read-out apparatus comprising:
i) a line light source for linearly irradiating stimulating rays onto an area of one surface of a stimulable phosphor sheet, on which the radiation image has been stored, the stimulating rays causing the stimulable phosphor sheet to emit light in proportion to an amount of energy stored thereon during its exposure to radiation,
ii) a line sensor for receiving light, which is emitted from the linear area of the one surface of the stimulable phosphor sheet exposed to the linear stimulating rays or from a linear area of the other surface of the stimulable phosphor sheet corresponding to the linear area of the one surface of the stimulable phosphor sheet, and performing photoelectric conversion of the received light, the line sensor comprising the plurality of the line sensor constituting units, each of which comprises a plurality of photoelectric conversion devices arrayed along a length direction of the linear area of the stimulable phosphor sheet, the plurality of the line sensor constituting units being arrayed along the length direction of the linear area of the stimulable phosphor sheet such that certain regions of adjacent line sensor constituting units overlap each other,
iii) scanning means for moving the stimulable phosphor sheet with respect to the line light source and the line sensor and in a direction different from the length direction of the linear area of the stimulable phosphor sheet, and
iv) reading means for successively reading outputs of the line sensor in accordance with the movement in order to obtain the radiation image signal, which represents the radiation image, the method comprising the steps of:
a) reading out a test image, in which edge patterns extending in a direction different from the length direction of the linear area of the stimulable phosphor sheet are embedded at positions corresponding to the overlapping regions of the line sensor constituting units, test image signal components of a test image signal, which represents the test image, being thereby acquired from each of the line sensor constituting units, and
b) performing the position matching processing on the radiation image signal components of the radiation image signal representing the radiation image, which radiation image signal components have been obtained from the plurality of the line sensor constituting units, and in accordance with edge pattern signal components, which represent the edge patterns embedded in the test image and are contained in the test image signal components of the test image signal representing the test image,
wherein the edge pattern are provided in multiple regions of non-storable regions disposed at an edge of the stimulable phosphor, said non-storable regions disposed part-way along a length of the stimulable phosphor.