Triggering of intraoral x-ray sensor using pixel array sub-sampling

Abstract

A method of capturing an x-ray image including providing an intraoral sensor having an array of pixels having a plurality of pixel clusters and a plurality of lines of pixels, each line of pixels having a first number of pixels different from the pixel clusters. The method may also include directing x-ray radiation toward the intraoral sensor and generating an electrical signal correlated to the x-ray radiation that impinges the pixel. The method may also include processing electrical signals generated by one or more pixels in the plurality of pixel clusters, generating at least one combined signal for at least one of the pixel clusters based on the signals from each of the pixels in the at least one of the pixel clusters, and initiating the capture of the image generated with information from each of the pixels in the array of pixels that is exposed to radiation.

What is claimed is: 
     
         1 . A method of capturing an x-ray image, the method comprising:
 providing an intraoral sensor having an array of pixels including a plurality of pixel clusters and a plurality of lines of pixels, each line of pixels having a first number of pixels different from the pixel clusters;   each of the pixel clusters including a second number of pixels that is less than the first number of pixels, the plurality of pixel clusters spaced regularly across the array;   directing x-ray radiation toward the intraoral sensor;   when the x-ray radiation impinges a pixel in the array of pixels, generating an electrical signal correlated to the x-ray radiation that impinges the pixel;   processing electrical signals generated by one or more pixels in the plurality of pixel clusters in an electronic control unit by reading the pixel clusters;   generating at least one combined signal for at least one of the pixel clusters based on the signals from each of the pixels in the at least one of the pixel clusters; and   when the at least one combined signal exceeds a predetermined threshold, initiating the capture of the image generated with information from each of the pixels in the array of pixels that is exposed to radiation.   
     
     
         2 . The method of  claim 1 , further comprising integrating values from pixels in the pixel clusters. 
     
     
         3 . The method of  claim 1 , further comprising reading the pixel clusters in a rolling-shutter mode. 
     
     
         4 . The method of  claim 3 , further comprising integrating values from pixels in the pixel clusters. 
     
     
         5 . The method of  claim 4 , further comprising performing pixel integration within a predetermined amount of time and reading each of the pixel clusters at a fraction of the predetermined amount of time. 
     
     
         6 . The method of  claim 5 , further comprising correlating signals from the pixels on a pixel-to-pixel basis prior to the pixel integration. 
     
     
         7 . The method of  claim 1 , wherein the pixel clusters include first pixel clusters and second pixel clusters, and wherein each first pixel cluster includes a predetermined number of pixels on a left-hand side of the array of pixels in a single line of pixels and each second pixel cluster includes a predetermined number of pixels on a right-hand side of the array of pixels in a single line of pixels. 
     
     
         8 . The method of  claim 1 , wherein the pixel clusters include first pixel clusters and second pixel clusters, and wherein each first pixel cluster includes a predetermined number of pixels on a left-hand side of the array of pixels in two or more lines of pixels and each second pixel cluster includes a predetermined number of pixels on a right-hand side of the array of pixels in two or more lines of pixels. 
     
     
         9 . The method of  claim 1 , further comprising performing at least one of two types of signal conditioning, double sampling and correlated double sampling. 
     
     
         10 . The method of  claim 1 , further comprising determining the predetermined threshold based on empirical information. 
     
     
         11 . The method of  claim 1 , further comprising determining the predetermined threshold using an adaptive technique. 
     
     
         12 . The method of  claim 1 , wherein each of the pixel clusters is read destructively by the electronic control unit. 
     
     
         13 . The method of  claim 1 , wherein each of the pixel clusters is read consecutively by the electronic control unit. 
     
     
         14 . The method of  claim 1 , wherein each of the pixel clusters is read non-destructively by the electronic control unit. 
     
     
         15 . An intraoral x-ray system comprising:
 an intraoral sensor having an array of pixels, the array of pixels including a plurality of pixel clusters and a plurality of lines of pixels, each line of pixels having a first number of pixels different from the pixel clusters   each of the pixel clusters including a second number of pixels that is less than the first number of pixels, the plurality of pixel clusters spaced regularly across the array, each of the pixels generating an electrical signal correlated to x-ray radiation that impinges that pixel; and   an electronic control unit connected to the array of pixels to receive electric signals from the array of pixels, and to read each pixel cluster, the electronic control unit configured to generate a combined signal for at least one of the pixel clusters and to initiate capture of an image generated with information from each of the pixels in the at least one of the pixel clusters that is exposed to radiation, when the at least one combined signal exceeds a predetermined threshold.   
     
     
         16 . The system of  claim 15 , wherein the electronic control unit is further configured to perform pixel integration. 
     
     
         17 . The system of  claim 15 , wherein pixel integration is performed within a predetermined amount of time and each of the one or more pixel clusters is read at a fraction of the predetermined amount of time. 
     
     
         18 . The system of  claim 15 , wherein the electronic control unit is further configured to correlate signals from the pixels on a pixel-to-pixel basis. 
     
     
         19 . The system of  claim 15 , wherein the electronic control unit is further configured to carry out a rolling-shutter mode scanning of the pixel clusters. 
     
     
         20 . The system of  claim 15 , wherein the pixel clusters include first pixel clusters and second pixel clusters, and wherein each first pixel cluster includes a predetermined number of pixels on a left-hand side of the array of pixels in at least one left-hand group of pixels and each second pixel cluster includes a predetermined number of pixels on a right-hand side of the array of pixels in at least one right-hand group of pixels. 
     
     
         21 . The system of  claim 15 , wherein the electronic control unit performs at least one of two types of signal conditioning, double sampling and correlated double sampling. 
     
     
         22 . The system of  claim 15 , wherein the predetermined threshold comprises at least one of: (a) an empirical threshold; and (b) a threshold determined using an adaptive technique. 
     
     
         23 . The system of  claim 15 , wherein the pixel clusters are located proximate to a perimeter of the array of pixels. 
     
     
         24 . The system of  claim 15 , wherein the electronic control unit reads each pixel cluster destructively. 
     
     
         25 . The system of  claim 15 , wherein the electronic control unit reads the pixel clusters one-at-a-time. 
     
     
         26 . The system of  claim 15 , wherein the image generated with information from the array of pixels includes information from at least one of the plurality of pixel clusters. 
     
     
         27 . The system of  claim 15 , wherein each of the pixel clusters is configured to be read non-destructively by the electronic control unit. 
     
     
         28 . A method of capturing an x-ray image, the method comprising:
 providing an intraoral sensor having an array of pixels, the array of pixels having a plurality of pixel clusters and a plurality of lines of pixels, each line of pixels having a first number of pixels different from the pixel clusters;   each of the pixel clusters including a second number of pixels that is less than the first number of pixels, the plurality of pixel clusters spaced regularly across the array;   directing x-ray radiation toward the intraoral sensor;   when the x-ray radiation impinges a pixel in the array of pixels, generating an electrical signal correlated to the x-ray radiation that impinges the pixel;   processing electrical signals generated by one or more pixels in the plurality of pixel clusters in an electronic control unit by reading the pixel clusters;   generating at least one combined signal for at least one of the pixel clusters based on signals from pixels in the at least one of the pixel clusters; and   when the at least one combined signal exceeds a predetermined threshold, initiating the capture of the image generated with information from each of the pixels in the array of pixels that is exposed to radiation.