Page  153 ï~~PRISM: PAfl'ERN RECOGNT Bernard Mon t-Reynaud CCRMA Music Department Stanford University Stanford, CA 94305 AB STRACT 0 PRISM is a system for visua musical sound. Its spectral analysis front-en techniques. Its 2-D display, using log-frequel physico-acoustic representations with music and MIDI scores. The visual orientation of tl computation: pattern-matching and polyphoni processing operators chosen by the user. The'c C on the MacII) supports indexing and colox applications in sound and music; it is also "re;

Page  154 ï~~resolution results from the STFT of the original signs found useful; others could be added to the system. A si displayed views is with the point-wise gray level min does indeed appear to offer both the highest time and fr The architecture treats input acquisition, filte log-f resampling, and display as four independent procc allows interrupt- driven data collection when in line implementation will allow real-time processing with the Feature extraction using image processin extraction method discussed at greater length in [6]. equidistant harmonics Ck*F) or (k)*F on the linear ax on the log axis, (log(K*F)) or (log(k)) + log(F), but arrangement which musicians know as the harmonic s' scaled to the display resolution, sweeps all possible fur Image convolution of the spectrogram with the harmc pitch detector which operates on all times and frequc result of a pitch extraction performed on a two voice

Page  155 ï~~Sampling frequency Fs Fg/2 Time, frequency resolution,AT, AF 2AT, AFU Fg4 4AT, II AF/4 m