Radiation image read-out method and apparatus with transformed pixel density based on radiation image size

Abstract

A radiation image read-out method comprises the steps of obtaining an image signal, which represents a radiation image, from a solid-state radiation detector constituted of a plurality of solid-state detecting devices for detecting radiation, which are arrayed in a matrix-like form along a main scanning direction and a sub-scanning direction and each of which corresponds to one pixel. A pixel density transforming process is performed on the image signal and in accordance with a pixel size, which is determined in accordance with a desired image size. In cases where read-out processing is performed with respect to different image sizes, a read-out density of a solid-state radiation detector need not be altered, but the method can cope with narrowness of an allowable width of the number of pixels in an image reproducing apparatus or an image filing apparatus.

What is claimed is:  
     
         1 . A radiation image read-out method, comprising the steps of obtaining an image signal, which represents a radiation image, from a solid-state radiation detector constituted of a plurality of solid-state detecting devices for detecting radiation, which are arrayed in a matrix-like form along a main scanning direction and a sub-scanning direction and each of which corresponds to one pixel, 
 wherein the improvement comprises the step of performing a pixel density transforming process on the image signal and in accordance with a pixel size, which is determined in accordance with a desired image size.    
     
     
         2 . A method as defined in  claim 1  wherein said pixel density transforming process is performed in accordance with a pixel density of an output apparatus, which receives an image signal having been obtained from said pixel density transforming process.  
     
     
         3 . A method as defined in  claim 2  wherein a pixel size of each of the solid-state detecting devices falls within the range of 100tm to 200 μm, and said pixel density transforming process is performed such that a pixel size in an image outputted from said output apparatus falls within the range of 40 μm to 100 μm.  
     
     
         4 . A method as defined in  claim 3  wherein said pixel density transforming process is performed such that the pixel size in the image outputted from said output apparatus falls within the range of 70 μm to 90 μm.  
     
     
         5 . A method as defined in  claim 1 ,  2 ,  3 , or  4  wherein, as an effective image size of the solid-state radiation detector becomes large, a magnification ratio of pixel density transformation in said pixel density transforming process is set to be low with respect to each of a row direction and a column direction.  
     
     
         6 . A method as defined in  claim 1 ,  2 ,  3 , or  4  wherein said pixel density transforming process is performed such that, with respect to each of a row direction and a column direction, a magnification ratio of pixel density transformation is equal to n/m, where n represents a positive integral number and m represents a positive integral number equal to at most a number of pixels of the solid-state detecting devices along the main scanning direction or the sub-scanning direction.  
     
     
         7 . A method as defined in  claim 1  wherein said pixel density transforming process is performed by multiplying each of image signal components, which are fed out from the solid-state detecting devices corresponding to a pixel of interest and the neighboring pixels, by a predetermined coefficient, and thereafter adding values of products obtained from the multiplication.  
     
     
         8 . A radiation image read-out apparatus, comprising means for obtaining an image signal, which represents a radiation image, from a solid-state radiation detector constituted of a plurality of solid-state detecting devices for detecting radiation, which are arrayed in a matrix-like form along a main scanning direction and a sub-scanning direction and each of which corresponds to one pixel, 
 wherein the improvement comprises the provision of pixel density transforming means for performing a pixel density transforming process on the image signal and in accordance with a pixel size, which is determined in accordance with a desired image size.    
     
     
         9 . An apparatus as defined in  claim 8  wherein said pixel density transforming means performs said pixel density transforming process in accordance with a pixel density of an output apparatus, which receives an image signal having been obtained from said pixel density transforming process.  
     
     
         10 . An apparatus as defined in  claim 9  wherein a pixel size of each of the solid-state detecting devices falls within the range of 100 μm to 200 μm, and said pixel density transforming means performs said pixel density transforming process such that a pixel size in an image outputted from said output apparatus falls within the range of 40 μm to 100 μm.  
     
     
         11 . An apparatus as defined in  claim 10  wherein said pixel density transforming means performs said pixel density transforming process such that the pixel size in the image outputted from said output apparatus falls within the range of 70 μm to 90 μm.  
     
     
         12 . An apparatus as defined in  claim 8 ,  9 ,  10 , or  11  wherein said pixel density transforming means operates such that, as an effective image size of the solid-state radiation detector becomes large, a magnification ratio of pixel density transformation in said pixel density transforming process is set to be low with respect to each of a row direction and a column direction.  
     
     
         13 . An apparatus as defined in  claim 8 ,  9 ,  10 , or  11  wherein said pixel density transforming means performs said pixel density transforming process such that, with respect to each of a row direction and a column direction, a magnification ratio of pixel density transformation is equal to n/m, where n represents a positive integral number and m represents a positive integral number equal to at most a number of pixels of the solid-state detecting devices along the main scanning direction or the sub-scanning direction.  
     
     
         14 . An apparatus as defined in  claim 8  wherein said pixel density transforming means performs said pixel density transforming process by multiplying each of image signal components, which are fed out from the solid-state detecting devices corresponding to a pixel of interest and the neighboring pixels, by a predetermined coefficient, and thereafter adding values of products obtained from the multiplication.  
     
     
         15 . A solid-state radiation detector, comprising a plurality of solid-state detecting devices for detection of radiation, which are arrayed in a matrix-like form and each of which corresponds to one pixel, and having read-out functions for feeding out a detection signal, which has been detected by the solid-state detecting devices, as an image signal, 
 wherein the improvement comprises the provision of pixel density transforming means for performing a pixel density transforming process on the image signal and in accordance with a pixel size, which is determined in accordance with a desired image size.