Disclosed is a signal processing circuit which outputs a digital word corresponding to a current source controlled by a physical response. An appropriate bipolar stimulating configuration can also be determined. The hand held device has at least one negotiable economic credit, or associated data, stored as electronic data in a database therein. The cutting device is movable between a retracted position wherein it is positioned within the shaft and an extended position wherein it is disposed at the distal end of the shaft. Specifically, the image processing apparatus determines a range of a writing area such that the approximation error is not larger than an allowance when this obtains the pixel position of the panoramic image corresponding to each position in the writing area on the screen by using one approximation function.