Apparatus and method for non-contact detection of hydrocarbon and other fluorescence materials on a surface

A method for detecting hydrocarbons on a surface, comprising:

• a. Irradiating a surface with a light source with a spectral band composition of incident wavelengths with a range of 100 nm-600 nm,
• b. Collecting fluorescence emissions and reflected light from said surface with a lens assembly with at least one convex lens and at least one optical filter, wherein said lens assembly is adjusted to create an image on an image plane located on the opposite side of said lens assembly relative to said surface, wherein said optical filter blocks transmission of all or most of said band of incident wavelengths,
• c. repeatedly measuring an intensity of light in at least one location on said image plane using at least one light sensing apparatus sensitive to visible wavelengths,
• d. determining the difference of said measured intensity of light from a baseline intensity for each measurement determining either,
• i) for each measurement if there is a high likelihood that a leak event occurred, wherein a high likelihood of said leak event is determined if the measured intensity exceeds a multiple-sigma threshold, a hydrocarbon area or volume indication threshold, or both, then updating a count of the number of occurrences of said leak event having said high likelihood during an observation interval, or
• ii) determining for each measurement a probability that a leak event has occurred, then determining a cumulative probability of a leak event having occurred during an observation interval which consists of one or more measurements described in steps a), b) and c),
• e. generating indicators for hydrocarbons leaking if a number of leak events during said observation interval exceeds a number threshold, or if said cumulative probability exceeds a threshold.