ZeroCrossings

Zero crossings: how often the signal changes sign over the window.

ZeroCrossings py

data

count

Type name: signal:ZeroCrossings
Plane: signal
Tags: analysis
Language: python
Tier: in-process
Bundle: complexity
Source: node-bundles/complexity/zero_crossings.py
Availability: available

Slots

Slot	Direction	Type
`data`	input	ARRAY
`count`	output	ARRAY

Parameters

`zero`

Name	Type	Default	Range	Doc
`normalize`	`bool`	`false`		Divide by the window length, for a rate per sample.

Source

The current source of this node, as it stands in the goofi repository at node-bundles/complexity/zero_crossings.py.

node-bundles/complexity/zero_crossings.py

"""ZeroCrossings — how often a signal changes sign, from antropy.

The crudest frequency estimate there is, and the cheapest: a sine at f crosses zero 2f times a
second. The last axis is time and is consumed; every axis before it survives.
"""

import antropy
import numpy as np
import goofi


class ZeroCrossings(goofi.Node):
    """Zero crossings: how often the signal changes sign over the window."""

    TAGS = ["analysis"]
    INPUTS = {"data": goofi.InputSlot(goofi.DataType.ARRAY, required=True)}
    OUTPUTS = {"count": goofi.DataType.ARRAY}
    PARAMS = {
        "zero": {
            "normalize": goofi.BoolParam(False, doc="Divide by the window length, for a rate per sample."),
        }
    }

    def process(self, data):
        out = antropy.num_zerocross(
            np.asarray(data.data, dtype=np.float64), normalize=self.params.zero.normalize, axis=-1
        )
        return np.asarray(out, dtype=np.float32), data.drop_axis(-1)

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