IMAGE DATA-ANALYSIS FOR THE NA35 STREAMER CHAMBER

In the collision of relativistic heavy ions with nuclear targets at th e CERN SPS up to several hundred charged particles in the momentum ran ge of 0.1-200 GeV/c are produced. These events have been recorded on f ilm by the NA35 streamer chamber. A computer environment for the analy sis of this data was developed and became operational at the Universit y of Frankfurt. This Frankfurt Image Processing System (PIPS) is a mod ular und distributed system allowing the application of image processi ng and image understanding techniques to digitized streamer chamber im ages as well as the interactive computer-assisted measurement of photo graphic streamer chamber pictures on traditional film projection table s.Automatic track reconstruction software has been developed which in turn utilizes a multitude of image processing and image understanding techniques. The efficiency of the pattern recognition and track recons truction processes is greater than 95% with a very good momentum resol ution dP/P = root(0.0009P)(2)+(0.0018)(2). So far about 20000 of these events have been processed. Currently approximately 50 events per day are automatically analysed.