Abstract: A dual energy method for CT scanning. Scanning is carried out at low and high energy levels, S.sub.2 and S.sub.1 respectively, each at a preselected dose level. Detected electronic signals (I.sub.2,I.sub.1) are digitized. A look up table is used to generate a pair of values from each pair of signals, one a photoelectric component and the other a Compton component. Each of these values are subjected to spatial filtering by a convolution filter function for each signal specially designed to increase the signal to noise ratio in the resultant combined image by exploiting the correlation in noise in the two values.

Abstract: A transaction processing system comprises an electronic cash register machine (ECR) and a balance settling machine. The ECR includes a keyboard from which the figures for individual items in one transaction are entered, and a memory in which the cumulative records of the figures are stored. An actual amount of money temporarily paid by a customer for the purchased items is also entered from the keyboard. A balance data representing an outstanding balance of money to be returned to the customer is calculated in the ECR. A recording medium on which the appropriate identification (ID) code is recorded is handed to the customer. The cash transaction data and the appropriate balance data together with the customer's ID code are sent to the balance settling machine.When the customer inserts his or her recording medium into the balance, settling machine, the ID code on the recording medium is read.