Scatter in x-ray apparatus and methods of their use

An x-ray apparatus comprising an x-ray source and a pixellated x-ray detector, the apparatus further comprising:

• a first database of values representative of material types and material thicknesses,
• a second database of scatter radiation values associated with material types and material thicknesses, and
• a processor configured to perform an algorithm which:
• i) compares an output signal of the x-ray detector with values in the first database and outputs a most likely material type and thickness from the first database;
• ii) derives from the second database scatter radiation values associated with one of the material type and material thickness as output in step (i), and the material type and material thickness as identified in a previous iteration of the algorithm;
• iii) subtracts the derived scatter radiation values from the output signal of the x-ray detector to produce a modified output signal;
• iv) performs a material and thickness identification step on the modified output signal by comparing the modified signal with values in the first database;
• and
• v) utilizes the identified material and thickness in at least one further iteration of steps (ii), (iii), and (iv) of the algorithm;
• wherein iteration is halted when it is determined that the modified output signal is optimized, wherein determining whether the modified output signal is optimized comprises:
• comparing values indicative of material type and thickness identified in the current iteration with comparison values comprising one of:
• values indicative of material type and thickness identified in a previous iteration, and
• averages of values indicative of material type and thickness identified in a number of previous iterations, and
• determining whether the values indicative of material type and thickness identified in the current iteration are within a threshold limit of the comparison values;
• wherein, if the compared values are within the threshold limit, then iteration of steps (ii) to (iv) of the algorithm is halted.