Ultrasonic images interpretation improvement for microassembling technologies characterisation

This paper deals with two techniques for improvement of ultrasonic images interpretation based on image and digital signal processing. The first technique concerns image processing. We propose an analytical model to evaluate the effective Point Spread Function (PSF) of a reflection scanning ultrasonic system. We present the great interest of the knowledge of the PSF for deconvolution of ultrasonic images based on Lucy-Richardson algorithm. With this technique, lateral resolution is strongly improved and real dimensions of an object can be reached that is necessary to improve the understanding and interpretation of an image The second technique concerns ultrasonic images showing different nature of defects. A better understanding of these images can be realized by means of time of flight detection. This technique concerns Time-Frequency (TF) analysis to determine nature and depth of defects with accuracy. Two applications of microassembling die-attach characterisation are presented using these methods. (C) 1997 Elsevier Science Ltd.