Image data from computed tomography (CT) scanners are in Hounsfield Units (HU). (HU are named after the inventor of the CT scanner, Sir Godfrey Hounsfield). The radiodensity of distilled water at STP is defined as zero HU, and the radiodensity of air is defined as -1000 HU. Some types of imaging data, such as Positron Emission Tomography (PET) need to be corrected for attenuation after knowing the HU. The HU scale can be transformed into attenuation coefficients (AC) according to the graph below. Using the relationship from the figure, write a Matlab script to convert HU to AC. Part a) Test your program for the following HU value: 0 Part b) Test your program for the following HU value: 1250 Relationship between HU and AC 0.3 (3071,0.262) $ 0.25 0.2 Attenuation coefficient (AC, cm) 0.15 0.1 -(0,0.093) 0.05 0 -1000 0 3000 1000 2000 CT value (HU) Your answer should be stored in the variable AC