User's Manual - Cornell Lab of Ornithology - Cornell University

Chapter 1: Getting StartedBoxy vs. smoothspectrogramsIf you stretch the horizontal or vertical scale of a “boxy” spectrogram (thedefault display style ) much, you’ll find that the spectrogram display, whichmay have seemed smooth as it was originally drawn, becomes increasinglyjagged or boxy. Canary displays one box of a specific shade of gray for eachpoint in time-frequency space where an amplitude has been calculated fromthe signal. The height and width of the boxes are determined by theparameters set in the Spectrogram dialog box, as discussed in Chapter 3. Ifyou want the display to appear smooth at any magnification, you can selectthe Smooth display style instead of Boxy in the Spectrogram Options dialogbox.If you’ve already created a spectrogram, you can still switch back and forthbetween boxy and smoothed displays without recalculating the spectrogram.Hold down the option key while clicking on the SPG button, and theSpectrogram Options dialog box will reappear. Click on the Smooth displaystyle button (see Figure 1.4), and click OK. The spectrogram will be redrawn,with grayscale values individually interpolated for every screen pixel in thedisplay. Smoothed spectrograms take longer to redraw after any change ofscale than boxy ones. See Chapter 3 for further discussion of the use of boxyand smoothed spectrograms.Views and panesAs mentioned earlier, Canary can display three different views of a signal; eachview is shown in a separate pane of a signal window. (So far, we havediscussed only the waveform and spectrogram views; the spectrum view isdiscussed in the next section.) It is helpful to understand the distinctionbetween views and panes. A view is a representation of a signal or part of asignal. A pane is part of a window, and is simply the graphic region of awindow. A pane may show only part of a view, for example, when the timeaxis of a waveform is stretched. Double-clicking on a pane selects the entireview.Creating a spectrumClick once in the waveform pane midway through the second syllable of thesong (the constant-frequency whistle at about 600 - 750 msec). Click on thespectrum (SPK) button to create a spectrum view of the signal at this point intime. You can think of a spectrum as being like a thin “slice” through thespectrogram at one moment in time. A dialog box like the one in Figure 1.7appears.18 Canary 1.2 User’s Manual