Delta modulated baseline restoration for photon counting computed tomography

A method for implementing non-linear baseline restoration (“BLR”), the method comprising:

• comparing a shaper voltage output from a shaper component of a photo-counting computed tomography (PCCT) signal chain with a baseline voltage to produce a comparator voltage indicative of whether the shaper voltage is above or below the baseline voltage at a given time;
• filtering the comparator voltage;
• and
• converting the filtered voltage signal to a current signal.

A photon-counting detector (“PCD”) comprising:

• a sensor for registering an interaction with a photon received at the PCD and forwarding a pulse indicative of the interaction to a signal chain;
• and
• a baseline restoration (“BLR”) circuit connected to the signal chain, the BLR circuit comprising:
• an input comparator for comparing a voltage pulse output from the signal chain with a baseline voltage, the input comparator outputting a single bit indicative of whether the shaper voltage is above or below the baseline voltage;
• and
• a low pass filter connected to filter a voltage signal output from the input comparator.

A photon-counting computed tomography (“PCCT”) system comprising:

• an X-ray source for generating X-ray photons;
• and
• a photon-counting detector (“PCD”) comprising:
• a sensor for registering an interaction with an X-ray photon received at the PCD after passing through an object of interest and forwarding a pulse indicative of the interaction to a signal chain;
• and
• a baseline restoration (“BLR”) circuit connected to the signal chain, the BLR circuit comprising:
• an input comparator for comparing a voltage pulse output from the signal chain with a baseline voltage, the input comparator outputting a single bit indicative of whether the shaper voltage is above or below the baseline voltage;
• and
• a low pass filter connected to filter a voltage signal output from the input comparator.