An encoded information reading (EIR) terminal can comprise a microprocessor, a memory, an EIR device including a two-dimensional imaging device, a motion sensing device, and a communication interface. The EIR terminal can be configured, responsive to detecting a pre-defined pattern in a first plurality of values received from the motion sensing device, to store in the memory a point of origin equal to a first spatial position of the EIR terminal. The EIR terminal can be further configured, responsive to detecting a user interface command, to determine, based on a second plurality of values received from the motion sensing device, a second spatial position of the EIR terminal relative to the point of origin, and to acquire an image of the object. The EIR terminal can be further configured to determine the image scale factor based on at least the second spatial position.