Detection of targets from hyperspectral imagery

A method of determining the presence of a target substance, the method comprising:

• receiving a hyperspectral image comprising spectra of a plurality of scene pixels indicative of light and other radiation absorbed by, or emitted from, a target substance;
• determining, in a target scoring engine, for each scene pixel, a measure of spectral match between a respective spectrum of the scene pixel and a reference spectrum of the target substance;
• determining, in a target scoring engine, a measure of spectral mismatch between a respective spectrum of the scene pixel and the reference spectrum of the target substance;
• and
• detecting, in a target detector, a presence of the target substance within the hyperspectral image in response to the determined measures of spectral match and spectral mismatch, wherein detecting a presence of the target substance comprises forming a ratio of the measure of spectral match and the measure of spectral mismatch, the ratio being indicative of presence of the target substance within the scene pixel.

A method of determining the presence of a target substance, the method comprising:

• receiving, in a target scoring engine, a hyperspectral image comprising spectra of a plurality of scene pixels indicative of light and other radiation absorbed by, or emitted from, a target substance;
• determining, in a target scoring engine, for each scene pixel, a measure of spectral match between a respective spectrum of the scene pixel and a reference spectrum of the target substance;
• determining, in a non-target scoring engine, for each scene pixel, a measure of spectral mismatch between a respective spectrum of the scene pixel and the reference spectrum of the target substance;
• detecting, in a target detector, a presence of the target substance within the hyperspectral image in response to the determined measures of spectral match and spectral mismatch;
• standardizing for each scene pixel the determined measure of spectral match and the determined measure of spectral mismatch.

An apparatus for detecting the presence of a target substance, comprising:

• image storage configured to store at least a portion of a hyperspectral image comprising spectra of a plurality of scene pixels indicative of light and other radiation absorbed by or emitted from, a target substance;
• target spectra storage configured to store a reference spectrum of the target substance;
• a target scoring engine in communication with the image storage and the target spectra storage, the target scoring engine configured to determine for each scene pixel a measure of spectral match between a respective spectrum of the scene pixel and a reference spectrum of the target substance;
• a non-target scoring engine in communication with the image storage and the target spectra storage, the non-target scoring engine configured to determine for each scene pixel a measure of spectral mismatch between a respective spectrum of the scene pixel and the reference spectrum of the target substance;
• and
• a target detector in communication with the target scoring engine and the non-target scoring engine, the target detector configured to detecting presence of the target substance within the hyperspectral image in response to the determined measures of spectral match and spectral mismatch, wherein the target scoring engine comprises a filter selected from the group consisting of:
• spectral matched filters and adaptive coherence/cosine estimator (ACE) filters.

A method of determining the presence of a target substance, the method comprising:

• receiving a hyperspectral image comprising spectra of a plurality of scene pixels indicative of light and other radiation absorbed by, or emitted from, a target substance;
• applying a first filter determining for each scene pixel, a measure of spectral match between a respective spectrum of the scene pixel and a reference spectrum of the target substance and a measure of spectral mismatch between a respective spectrum of the scene pixel and the reference spectrum of the target substance;
• applying a second filter determining for each scene pixel, an estimate of a respective mixture coefficient for each spectrum of the at least one target substance, whereby a product of the respective mixture coefficients and the target spectra representing an estimate of the at least one target present within the scene pixel, and a residual spectrum indicative of that portion of the whitened pixel spectrum not in the estimate of the at least one target;
• standardizing outputs of each of the first and second filters;
• and
• combining the standardized outputs of the first and second filters, the combination indicative of a detection a presence of the target substance within the hyperspectral image, wherein applying the first filter includes applying a matched filter to the spectrum of the scene pixel or a filter adapted to measure angular deviation between the spectrum of the scene pixel and the reference spectrum of the target substance.