MeasureTool » History » Version 7

Chris Cannam, 2013-03-05 10:50 AM

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h1. About the Measure tool and its limitations
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The Sonic Visualiser Help reference "describes the Measure tool":http://www.sonicvisualiser.org/doc/reference/2.0/en/#measurements like this:
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> The measure tool enables you to obtain measurements in scale units (such as time in the X coordinate, or whatever the Y coordinate of the current layer represents) corresponding to certain pixel positions. To measure a region, just click and drag a rectangle covering it, using the left mouse button with the measure tool selected ...
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> It's important to note that the measurements shown in this way are based entirely on the pixel coordinates of the measurement rectangle, not on properties of the data being displayed.
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The measure tool also has the ability to produce an automatic bounding box for a graphical feature, when double-clicked:
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> The area enclosed by the rectangle is based on the extent of similarly-coloured pixels surrounding the click position: it is entirely graphical, involving no audio analysis, and so depends on the gain and colour scheme in use in the spectrogram.
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Here's an example of what that means in terms of the practical limitations of this tool.
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This picture is a composite of three separately highlighted Measure boxes: