Image Processing In Acoustic Microscopy

Abstract

The term “image processing” has become synonymous with computer processing because of the immense power and versatility of computer processing methods. There is a tendency, therefore, to overlook optical and analog electronic processing methods. In the field of acoustic microscopy with its high frequencies and wide bandwidth requirements, it is still attractive to consider some of the older methods of image processing, even though these methods may not offer the same flexibility and versatility of the processing software. Eight bit video digitizers operating at 30 MHz are available at nominal cost, and can be readily used for low resolution image processing; however, the 100 or 200 MHz digitizers required for higher resolution are still very costly. The optical and analog electronic processing methods offer a much higher data rate than present day digital systems can handle. It is therefore cost effective to utilize analog image processing systems in acoustic microscopy.

In this paper we will be considering various means of data presentation such as optical or acoustic spatial domain imaging in register with parametric mapping. Frequency domain imaging may be achieved using Fourier optics to characterize the spatial frequency of scatterers within the specimen. Time domain imaging is used to visualize events taking place on a time scale which is short compared to a television frame rate. The time domain imaging can be combined with time varying parametric recording. These multi-parameter imaging techniques can be of immense value in appreciating and understanding dynamic biological events.