Method and system of automatically determining when x-ray radiation has been received at a sensor

Abstract

A system and method for automatic detection of x-rays at an x-ray sensor. A source emits x-ray radiation towards an x-ray sensor, and the x-ray sensor automatically detects the x-ray radiation. The x-ray sensor automatically detects x-ray radiation by evaluating a time series and determining that a voltage threshold is crossed a certain amount of time earlier than the average time it takes the voltage threshold to be crossed from dark current and other noise.

What is claimed is: 
     
         1 . A method of automatically detecting x-ray radiation with an x-ray sensor, the x-ray sensor having a pixel array, the method comprising:
 adaptively resetting the pixel array based on a dark current; and   determining that x-ray radiation has been received at at least a portion of the pixel array when a trigger threshold is passed.   
     
     
         2 . The method of  claim 1 , wherein adaptively resetting the pixel array based on the dark current includes determining an elapsed time between a reset of the pixel array and a determination that the trigger threshold has been crossed due to the dark current. 
     
     
         3 . The method of  claim 1 , wherein the dark current indicates a temperature of the x-ray sensor. 
     
     
         4 . The method of  claim 3 , further comprising generating an error condition if the temperature of the x-ray sensor indicated by the dark current exceeds a predetermined level. 
     
     
         5 . The method of  claim 1 , wherein the trigger threshold comprises a predetermined voltage level, and wherein a predetermined amount of charge stored on the at least a portion of the pixel array causes a voltage potential at a diode to drop below the trigger threshold. 
     
     
         6 . The method of  claim 1 , further comprising:
 determining that x-ray radiation is no longer being received, and   reducing an integration time for a subsequent x-ray radiation exposure based on a duration of the x-ray radiation received at the at least a portion of the pixel array.   
     
     
         7 . An x-ray sensor that automatically detects receipt of x-rays, the x-ray sensor including a processor and a pixel array, the processor configured to:
 adaptively reset the pixel array based on a dark current;   determine that x-ray radiation has been received at at least a portion of the pixel array based on passing a trigger threshold; and   after determining that x-ray radiation has been received, output data from the pixel array to be used to generate an x-ray image.   
     
     
         8 . The x-ray sensor of  claim 7 , wherein adaptively resetting the pixel array based on the dark current includes determining an elapsed time between a reset of the pixel array and a determination that the trigger threshold has been crossed due to the dark current. 
     
     
         9 . The x-ray sensor of  claim 7 , wherein the trigger threshold comprises a predetermined voltage level, and wherein a predetermined amount of charge stored on the at least a portion of the pixel array causes a voltage potential at a diode to drop below the trigger threshold. 
     
     
         10 . The x-ray sensor of  claim 7 , wherein the processor is further configured to
 determine that x-ray radiation is no longer being received, and   reduce an integration time for a subsequent x-ray radiation exposure based on a duration of the x-ray radiation received at the at least a portion of the pixel array.   
     
     
         11 . The x-ray sensor of  claim 7 , wherein the dark current indicates a temperature of the x-ray sensor. 
     
     
         12 . The x-ray sensor of  claim 11 , wherein the processor is further configured to generate an error condition if the temperature of the x-ray sensor indicated by the dark current exceeds a predetermined level.