Method and apparatus to recover a dead pixel in digital imaging systems

A radiation detecting apparatus comprising:

• an array of elements for converting individual received radiation events into corresponding radiation event signals, one of the radiation converting defective;
• a means for digitizing the radiation event signals from at least non-defective elements;
• a means for assigning at least two of the individual radiation converting elements of the array as contributing pixels whose output signals are supplied to the defective pixel output signal generating means;
• a means for generating a radiation event signal for the defective radiation converting element based on the radiation event signals from the contributing pixels,the defective pixel output signal generating means including:
• a table having a position for each of the contributing pixels;
• a means for passing a token among the table positions;
• a means for receiving the radiation event signals from the contributing radiation converting elements and accessing the table to determine whether the corresponding table position holds the token, in response to the corresponding table position holding the token, generating the radiation event signal for the defective radiation converting element and causing the token passing means to pass the token.

A gamma camera comprising:

• a two-dimensional array of radiation detector elements which receives incident gamma radiation events and produces corresponding output signals, one of the radiation detector elements being defective;
• at least one analog-to-digital converter for converting the element output signals into a digital value indicative of spatial location on the array and energy of the incident gamma radiation event;
• and
• a virtual event generator which;
• receives the output signals from contributing radiation detecting elements of the array,
• determines whether the contributing radiation detecting elements are randomly assigned a token, and
• generates digital output signals for the defective radiation detecting element based on the output signals from contributing radiation detecting elements of the array which hold the token.

A method of detecting radiation comprising:

• receiving radiation events at an array of pixel locations and generating corresponding radiation event signals, at least one of the locations being defective;
• digitizing the radiation event signals from non-defective pixel locations;
• awarding a token to at least one of the non-defective pixel location adjacent to the defective pixel location:
• in response to receiving a radiation event signal corresponding to the non-defective pixel location with the token, generating radiation event signals for the defective pixel location based on the radiation event signals from the at least one non-defective locations with the token and transferring the token to another non-defective pixel location adjacent to the defective pixel location.

An imaging apparatus comprising:

• a detector including an array of detector elements for converting radiation events into corresponding radiation event signals;
• a means for determining defective detector elements of the array;
• a means for assigning detector elements proximate to each defective element as contributing detector elements whose outputs form the basis of the generating of the radiation event signal for the defective detector elements:
• and a means for generating radiation event signals for defective detector elements in response to receivng a radiation event signal corresponding to, a randomly selected contributing detector element, the selected contributing elements changing randomly.