RESPITE: The CASA Toolkit Page: Documentation: Block Library Index:Peak


The basic operation of Peak is to take a one-dimensional frame of data and to output the height and the index of the first (i.e. lowest indexed) peak in the data. The peak's height is sent to out1 and the peak's index is sent to out2. As not every frame of data will have a peak (i.e. the data maybe monotonically increasing or decreasing, or flat), the block also outputs a bolean to indicate whether or not a peak was found. This is sent to out3.

The peak block has been generalised to work on N dimensional frame data. If there is more than one dimension to the frame then the block will operate on every one dimensional line through the data parallel to a given axis. In this case output will be frames of N-1 data. If no axis is specified then the axis of the outer dimension is taken as default.

(A peak is defined as a point, x(n), on an axis, x, such that x(n)>x(n-1) and x(n)>x(n+1).)

Inputs Meaning Sample 1-D frame $\ge$2-D frame
in1 frame data No Yes Yes

Outputs Meaning
out1 the peak heights
out2 the peak locations i.e. index values
out3 booleans indicating whether peaks exists

Parameters Type Default Meaning
AXIS String (outer) Name of axis to reduce

Documentation for CTKv1.1.4 - Last modified: Thu Jun 28 14:51:58 BST 2001