Illustration to show the patterns used for computing CIM1524, which is an average of 8 impedances values as shown in the figure. The 8 impedances values used are: Z1524, Z2635, Z3746, Z4857, Z5168, Z6271, Z7382, Z8413. Notice that the subscript ‘1524’ in CIM1524 is only used as an index to represent an average of data acquired for the 8 patterns shown here. These 8 patterns are ‘corresponding’ in the sense that each pattern is a rotated version of pattern 1524 (current applied through electrodes 1 and 5, and potential difference sensed across electrodes 2 and 4).