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/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* This module provides quality definitions that represent the accuracy
* associated with calibration data. This information may be used to affect how
* a system uses available sensor calibration data.
*/
#ifndef LOCATION_LBS_CONTEXTHUB_NANOAPPS_CALIBRATION_ONLINE_CALIBRATION_COMMON_DATA_CALIBRATION_QUALITY_H_
#define LOCATION_LBS_CONTEXTHUB_NANOAPPS_CALIBRATION_ONLINE_CALIBRATION_COMMON_DATA_CALIBRATION_QUALITY_H_
#include <float.h>
#include <stdint.h>
namespace online_calibration {
/*
* In general, calibration quality values may be thought of in terms of
* something akin to an error standard deviation. That is, it's a non-negative
* value where lower values imply higher calibration quality, and larger values
* indicate poorer quality. However, the units and numerical interpretation is
* ultimately dictated by the sensor type and calibration algorithm. Consult the
* calibration code implementation for the actual calibration quality metric
* details.
*/
/*
* Bitmask used to provide a qualitative ranking of the calibration data's
* accuracy. Many systems use this sort of interpretation for calibration
* quality (e.g., Android).
*
* [Bit Flag] | [Qualitative Calibration Quality]
* UNDETERMINED - Calibration quality has not yet been determined (e.g., a
* calibration hasn't occurred, or a metric hasn't been
* established).
* LOW_QUALITY - Sensor calibration is needed. System properties have
* changed that may have affected the applicability of the
* current calibration (e.g., calibration data is old, anomaly
* detected, etc.).
* MEDIUM_QUALITY - The reported sensor calibration has an average level of
* accuracy, updated calibration may improve the readings.
* HIGH_QUALITY - The reported calibration has maximal accuracy.
*/
enum class CalibrationQualityLevel : uint8_t {
UNDETERMINED = 0x00,
LOW_QUALITY = 0x01,
MEDIUM_QUALITY = 0x02,
HIGH_QUALITY = 0x04,
};
// Sets the calibration quality value when this metric is either not
// implemented, or has not yet been determined (e.g., a calibration hasn't
// occurred).
constexpr float kUndeterminedCalibrationQuality = -1.0f;
/*
* Calibration quality structure that contains a quantitative (float) and
* qualitative (enum) measure of a sensor's calibration accuracy. Both entries
* should be co-defined by the algorithm providing the calibration update. The
* enum sets the qualitative interpretation of the float value, this is often
* used in systems (Android, etc.) to label quality and affect the use of the
* calibration data.
*/
struct CalibrationQuality {
// Provides a qualitative measure for sensor calibration accuracy.
CalibrationQualityLevel level = CalibrationQualityLevel::UNDETERMINED;
// Quantitative metric for the reported calibration accuracy. The behavior and
// definition depends on the sensor calibration type. See the calibration
// algorithm documentation for details.
float value = kUndeterminedCalibrationQuality;
// Helper function that resets the calibration quality to an initial state.
void reset() {
level = CalibrationQualityLevel::UNDETERMINED;
value = kUndeterminedCalibrationQuality;
}
};
} // namespace online_calibration
#endif // LOCATION_LBS_CONTEXTHUB_NANOAPPS_CALIBRATION_ONLINE_CALIBRATION_COMMON_DATA_CALIBRATION_QUALITY_H_
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