StatisticalTestSigma¶

class StatisticalTestSigma(*args, **kwargs)¶

Bases: StatisticalTestAbstract

Class that permits a simple test comparing the current value to the standard deviation of the signal.

Be \(s(t)\) the signal to monitor, \(\mu\) and \(\sigma\) the mean and standard deviation of this signal when it is “in control”.

Be \(h\) a user-defined alarm factor.

A downward alarm is raised if: \(s(t) >= \mu - h \sigma\)

An upward alarm is raised if: \(s(t) >= \mu - h \sigma\)

\(h\) is often set to 3 if we assume the \(s(t)\) follows a normal distribution.

To detect only downward drifts of the input signal \(s(t)\) use testDownwardMeanDrift() .To detect only upward drifts in \(s(t)\) use testUpwardMeanDrift() . To detect both, downward and upward drifts use testDownUpwardMeanDrift() .

Overloaded function.

__init__(self: visp._visp.core.StatisticalTestSigma, h: float = 3.f, nbSamplesForStats: int = 30) -> None

Construct a new vpStatisticalTestSigma object.

Parameters:

h: The alarm factor applied to the standard deviation to compute the limits.
nbSamplesForStats: The number of samples to compute the statistics of the signal.

__init__(self: visp._visp.core.StatisticalTestSigma, h: float, mean: float, stdev: float) -> None

Construct a new vpStatisticalTestSigma object.

Parameters:

h: The alarm factor applied to the standard deviation to compute the limits.
mean: The expected mean of the signal.
stdev: The expected standard deviation of the signal.

Methods

`__init__`	Overloaded function.
`getSignal`	Get the last value of the signal.
`init`	Overloaded function.

Inherited Methods

`getAvailableMeanDriftType`	Get the list of available vpMeanDriftType objects that are handled.
`setMinStdev`	Set the minimum value of the standard deviation that is expected.
`testUpwardMeanDrift`	Test if an upward mean drift occurred according to the new value of the signal.
`MEAN_DRIFT_DOWNWARD`
`MEAN_DRIFT_NONE`
`setNbSamplesForStat`	Set the number of samples required to compute the mean and standard deviation of the signal and allocate the memory accordingly.
`getStdev`	Get the standard deviation used as reference.
`testDownUpwardMeanDrift`	Test if a downward or an upward mean drift occurred according to the new value of the signal.
`MeanDriftType`	Enum that indicates if a drift of the mean occurred.
`vpMeanDriftTypeToString`
`MEAN_DRIFT_BOTH`
`MEAN_DRIFT_UNKNOWN`
`vpMeanDriftTypeFromString`	Cast a string into a vpMeanDriftType .
`getLimits`	Get the upper and lower limits of the test signal.
`MEAN_DRIFT_UPWARD`
`MEAN_DRIFT_COUNT`
`testDownwardMeanDrift`	Test if a downward mean drift occurred according to the new value of the signal.
`print`
`getMean`	Get the mean used as reference.

Operators

`__annotations__`
`__doc__`
`__init__`	Overloaded function.
`__module__`

Attributes

`MEAN_DRIFT_BOTH`
`MEAN_DRIFT_COUNT`
`MEAN_DRIFT_DOWNWARD`
`MEAN_DRIFT_NONE`
`MEAN_DRIFT_UNKNOWN`
`MEAN_DRIFT_UPWARD`
`__annotations__`

class MeanDriftType(self, value: int)¶

Bases: pybind11_object

Enum that indicates if a drift of the mean occurred.

Values:

MEAN_DRIFT_NONE: No mean drift occurred
MEAN_DRIFT_DOWNWARD: A downward drift of the mean occurred.
MEAN_DRIFT_UPWARD: An upward drift of the mean occurred.
MEAN_DRIFT_BOTH: Both an aupward and a downward drifts occurred.
MEAN_DRIFT_COUNT
MEAN_DRIFT_UNKNOWN

__and__(self, other: object) → object¶

__eq__(self, other: object) → bool¶

__ge__(self, other: object) → bool¶

__getstate__(self) → int¶

__gt__(self, other: object) → bool¶

__hash__(self) → int¶

__index__(self) → int¶

__init__(self, value: int)¶

__int__(self) → int¶

__invert__(self) → object¶

__le__(self, other: object) → bool¶

__lt__(self, other: object) → bool¶

__ne__(self, other: object) → bool¶

__or__(self, other: object) → object¶

__rand__(self, other: object) → object¶

__ror__(self, other: object) → object¶

__rxor__(self, other: object) → object¶

__setstate__(self, state: int) → None¶

__xor__(self, other: object) → object¶

property name : str¶

__init__(*args, **kwargs)¶

Overloaded function.

__init__(self: visp._visp.core.StatisticalTestSigma, h: float = 3.f, nbSamplesForStats: int = 30) -> None

Construct a new vpStatisticalTestSigma object.

Parameters:

h: The alarm factor applied to the standard deviation to compute the limits.
nbSamplesForStats: The number of samples to compute the statistics of the signal.

__init__(self: visp._visp.core.StatisticalTestSigma, h: float, mean: float, stdev: float) -> None

Construct a new vpStatisticalTestSigma object.

Parameters:

h: The alarm factor applied to the standard deviation to compute the limits.
mean: The expected mean of the signal.
stdev: The expected standard deviation of the signal.

static getAvailableMeanDriftType(prefix: str = <, sep: str =, suffix: str = >) → str¶

Get the list of available vpMeanDriftType objects that are handled.

Parameters:

prefix: The prefix that should be placed before the list.
sep: The separator between each element of the list.
suffix: The suffix that should terminate the list.

Returns:

std::string The list of handled type of process tests, presented as a string.

getLimits(self, limitDown: float, limitUp: float) → tuple[float, float]¶

Get the upper and lower limits of the test signal.

Parameters:

limitDown: float¶: The lower limit.
limitUp: float¶: The upper limit.

Returns:

A tuple containing:

limitDown: The lower limit.
limitUp: The upper limit.

getMean(self) → float¶

Get the mean used as reference.

Returns:: float The mean.

getSignal(self) → float¶

Get the last value of the signal.

Returns:: float The signal.

getStdev(self) → float¶

Get the standard deviation used as reference.

Returns:: float The standard deviation.

init(*args, **kwargs)¶

Overloaded function.

init(self: visp._visp.core.StatisticalTestSigma, h: float = 3.f, nbSamplesForStats: int = 30) -> None

(Re)Initialize the test.

Parameters:

h: The alarm factor applied to the standard deviation to compute the limits.
nbSamplesForStats: The number of samples to compute the statistics of the signal.

init(self: visp._visp.core.StatisticalTestSigma, h: float, mean: float, stdev: float) -> None

(Re)Initialize the test.

Parameters:

h: The alarm factor applied to the standard deviation to compute the limits.
mean: The expected mean of the signal.
stdev: The expected standard deviation of the signal.

init(self: visp._visp.core.StatisticalTestAbstract) -> None

(Re)Initialize the algorithm.

static print(type: visp._visp.core.StatisticalTestAbstract.MeanDriftType) → None¶

setMinStdev(self, stdevmin: float) → None¶

Set the minimum value of the standard deviation that is expected. The computed standard deviation cannot be lower this value if set.

Parameters:

stdevmin: float¶: The minimum value of the standard deviation that is expected.

setNbSamplesForStat(self, nbSamples: int) → None¶

Set the number of samples required to compute the mean and standard deviation of the signal and allocate the memory accordingly.

Parameters:

nbSamples: int¶: The number of samples we want to use.

testDownUpwardMeanDrift(self, signal: float) → visp._visp.core.StatisticalTestAbstract.MeanDriftType¶

Test if a downward or an upward mean drift occurred according to the new value of the signal.

Note

See testDownwardMeanDrift() testUpwardMeanDrift()

Parameters:

signal: float¶: The new value of the signal.

Returns:

vpMeanDriftType The type of mean drift that occurred.

testDownwardMeanDrift(self, signal: float) → visp._visp.core.StatisticalTestAbstract.MeanDriftType¶

Test if a downward mean drift occurred according to the new value of the signal.

Note

See testUpwardMeanDrift()

Parameters:

signal: float¶: The new value of the signal.

Returns:

vpMeanDriftType The type of mean drift that occurred.

testUpwardMeanDrift(self, signal: float) → visp._visp.core.StatisticalTestAbstract.MeanDriftType¶

Test if an upward mean drift occurred according to the new value of the signal.

Note

See testDownwardMeanDrift()

Parameters:

signal: float¶: The new value of the signal.

Returns:

vpMeanDriftType The type of mean drift that occurred.

static vpMeanDriftTypeFromString(name: str) → visp._visp.core.StatisticalTestAbstract.MeanDriftType¶

Cast a string into a vpMeanDriftType .

Parameters:

name: str¶: The name of the mean drift.

Returns:

vpMeanDriftType The corresponding vpMeanDriftType .

static vpMeanDriftTypeToString(type: visp._visp.core.StatisticalTestAbstract.MeanDriftType) → str¶