xtos_signal_p300_quality_gate

Validates P300 trial fields and summarizes detection rate, mean z, latency deviation, and passed.

On this page

Declaration

#include <xtos/signal.h>

int xtos_signal_p300_quality_gate(const struct xtos_p300_feature *trials,
                                  size_t trial_count,
                                  size_t min_valid_trials,
                                  double min_detection_rate,
                                  double min_mean_z_score,
                                  double max_latency_stddev_ms,
                                  struct xtos_p300_quality *result);

Parameters

Parameter	Type	Description
trials	const struct xtos_p300_feature *	Non-NULL trial array with at least trial_count entries.
trial_count	size_t	Number of trials, greater than zero.
min_valid_trials	size_t	Minimum valid trials required to pass, greater than zero.
min_detection_rate	double	Finite threshold in [0,1].
min_mean_z_score	double	Finite lower bound for mean z score; negative values are allowed.
max_latency_stddev_ms	double	Finite nonnegative latency standard-deviation limit in milliseconds.
result	struct xtos_p300_quality *	Non-NULL caller-provided output structure.

Output fields

Field	Type	Meaning
trials_total	size_t	Total number of input trials.
trials_valid	size_t	Number of trials that pass field-consistency checks.
trials_detected	size_t	Number of valid trials whose detected flag is 1.
trials_rejected	size_t	Number of trials rejected by validity checks.
detection_rate	double	trials_detected / trials_valid; 0 when there are no valid trials.
mean_peak_z_score	double	Mean peak_z_score across valid trials.
mean_peak_latency_ms	double	Mean peak latency across valid trials, in milliseconds.
peak_latency_stddev_ms	double	Population standard deviation of valid-trial latency, in milliseconds.
passed	int	Whether all gate conditions pass; 1 when passed, otherwise 0.

Return value

Returns 0 when arguments are valid and statistics complete, even when passed=0; returns -1 for invalid arguments.

Errors

errno	Condition
EINVAL	trials or result is NULL, a count is zero, min_detection_rate is outside [0,1], any threshold is non-finite, or max_latency_stddev_ms is negative.

Notes

Each trial is checked for finite fields, stddev, z consistency with amplitude/stddev, energy lower bound, and detected=0/1; any rejected trial makes passed=0.
Statistics use population latency standard deviation among valid trials; with no valid trial the function still returns 0 with passed=0.
The function allocates no memory and does not modify trials; the caller owns result.

Example

Source

This reference describes headers and implementation at OpenXTOS commit dd313955ad57542bcd2af8827157d1bbd0cf5e83.