Method and apparatus for estimating odor concentration using an electronic nose

A system for obtaining an estimate of the concentration of an odor in an air sample from data obtained by evaluating the sample with a sensor-array type electronic nose, the system comprising:

• a component for processing a set of air sample data including sensor-array data obtained from evaluating the air sample with the sensor-array type electronic nose and measurements of the humidity of the air sample and clean reference air used by the electronic nose to reduce noise in the air sample data and to decrease the dimensionality of that set of data to a predetermined number of dimensions, thereby obtaining a set of the predetermined number of air sample components;
• and
• a component for applying a non-linear transformation to the set of air sample components to obtain as output an estimate of the concentration of the odor in the air sample,
• the non-linear transformation using parameters obtained by:
• using an olfactometer to obtain discrete measurements of odor concentration from each of a plurality of calibration samples of air containing the odor,
• using the sensor-array type electronic nose to obtain a discrete set of calibration data from each of the calibration samples, each set including sensor-array data and measurements of the humidity of the calibration sample and the clean reference air used by the electronic nose,
• processing each set of calibration data to reduce noise in the air sample data and to decrease the dimensionality of that set of data to a predetermined number of dimensions, thereby obtaining a discrete set of the predetermined number of calibration components, and
• applying a non-linear regression to the sets of calibration components as input data and the corresponding measured odor concentrations as expected output to obtain the parameters of a non-linear transformation.

A system for obtaining an estimate of the concentration of an odor in an air sample from data obtained by evaluating the sample with a sensor-array type electronic nose, the system comprising:

• a processor component for applying principal components analysis to a set of air sample data including sensor-array data obtained from evaluating the air sample with the sensor-array type electronic nose and measurements of the humidity of the air sample and clean reference air used by the electronic nose to obtain a predetermined number of principal components of the air sample data;
• and
• a neural network component for processing the principal components obtained from the air sample to obtain as output an estimate of the concentration of the odor in the air sample,
• the neural network using parameters obtained by:
• using an olfactometer to obtain discrete measurements of odor concentration from each of a plurality of calibration samples of air containing the odor,
• using the sensor-array type electronic nose to obtain a discrete set of calibration data from each of the calibration samples, each set including sensor-array data and measurements of the humidity of the calibration sample and the clean reference air used by the electronic nose,
• applying principal components analysis to each set of calibration data to obtain a discrete set of the predetermined number of principal components, and
• training a neural network using the sets of principal components as input data and the corresponding measured odor concentrations as expected output to obtain the parameters of a trained neural network.