Substance or contamination detection

Abstract

A spectroscopic method and system detects the amount of one or more substances or contaminants in or on a product, such as fecal contamination on meat samples.

1 . A method for determining the amount of one or more substances or contaminants in or on an illuminated product, the method comprising the steps of:
 receiving a first signal indicative of intensity of light emitted from the product across a first waveband,   receiving a second signal indicative of intensity of light emitted from the product across a second waveband containing one or more wavelengths associated with the fluorescent properties of the contaminants or substances to be detected,   determining or predicting a value indicative of an amount of the substance or contaminant, for each of, or at least one of, the one or more substances or contaminants in or on the product, from the first and second signals and from predetermined information relating to fluorescence behaviour of a same or similar product or a main or more abundant substance of the product isolated from the substance or contaminant (hereinafter referred to as isolated product) and/or relating to the fluorescence behaviour of the substance or contaminant isolated from the product.   
     
     
         2 . The method as claimed in  claim 1  wherein the second waveband is within the first waveband. 
     
     
         3 . The method as claimed in  claim 1  wherein the second waveband is outside the first waveband. 
     
     
         4 . The method as claimed in any one of  claims 1  to  3  wherein the step of determining or predicting the value indicative of the amount of the substance or contaminant comprises:
 separating from the first signal a portion of the signal relating to the substance or contaminant based on: the second signal, the fluorescent behaviour of the substance or contaminant in isolation from the product and the fluorescent behaviour of the isolated product. 
 
     
     
         5 . The method as claimed in any one of  claims 1  to  4  further comprising determining or predicting a value indicative of an amount of a main or more abundant substance of the product by separating from the first signal a portion of the signal relating to the main substance based on: the second signal, the fluorescent behaviour of each isolated substance or contaminant and the fluorescent behaviour of the isolated product. 
     
     
         5 . The method as claimed in any one of  claims 1  to  4  wherein the predetermined information relates to:
 first and second isolated product signals indicative of the light emitted from the isolated (uncontaminated) product across the first and second wavebands respectively in response to optical excitation, and 
 for each of the one or more isolated substances or contaminants, first and second isolated substance or contaminant signals indicative of the light emitted from the isolated substance or contaminant within the first and second wavebands respectively in response to optical excitation. 
 
     
     
         6 . The method as claimed in  claim 5  wherein the predetermined information is indicative of: a strength of each of the first and second isolated product signals and for each of the one or more isolated substances or contaminants, a strength of each the first and second isolated substance or contaminant signals. 
     
     
         7 . The method as claimed in  claim 6  wherein the strength of the isolated product signal is an integral of an intensity of the isolated product signal across the relevant waveband, and the strength of the isolated substance or contaminant signal is an integral of an intensity of the isolated substance or contaminant signal across the relevant waveband. 
     
     
         8 . The method as claimed any one of  claims 5  to  7  wherein the predetermined information includes one or more of:
 a normalised strength of the first and/or second isolated product signal relative to the first isolated product signal, and 
 a normalised strength of the first and/or second isolated substance or contaminant signal relative to the first isolated substance or contaminant signal, for each of the isolated substances or contaminants. 
 
     
     
         9 . The method as claimed any one of  claims 6  to  8  wherein the step of determining or predicting the value indicative of the amount of the substance or contaminant comprises multiplying the first and second signals by the inverse of a matrix containing the strength of each of the first and second isolated product signals and the strength of each the first and second isolated substance or contaminant signals, for each of substance or contaminants. 
     
     
         10 . The method as claimed any one of  claims 1  to  9  further comprising, prior to receiving the first and second signals, the steps of:
 illuminating the product with light at an excitation wavelength outside the first and second wavebands, 
 receiving light emitted from the product in response to the illumination, and 
 filtering the emitted light into first and second filtered light signals within the first and second wavebands respectively. 
 
     
     
         11 . The method as claimed any one of  claims 1  to  10  further comprising the step of deriving the predetermined information. 
     
     
         12 . The method as claimed in  claim 11  wherein the step of deriving the predetermined information comprises:
 obtaining the first and second isolated product signals, 
 obtaining for each of the substances or contaminants, the first and second isolated substance or contaminant signal. 
 
     
     
         13 . The method as claimed in  claim 12  wherein the step of obtaining the first and second isolated product signals comprises:
 illuminating the isolated product with light at the excitation wavelength outside the first and second wavebands, 
 receiving light emitted from the product in response to the illumination, and 
 filtering the emitted light into first and second filtered light signals within the first and second wavebands respectively. 
 
     
     
         14 . The method as claimed in either  claim 12  or  claim 13  wherein the step of obtaining the first and second isolated substance or contaminant signals comprises:
 illuminating the isolated substance or contaminant with light at the excitation wavelength outside the first and second wavebands, 
 receiving light emitted from the substance or contaminant in response to the illumination, and 
 filtering the emitted light into first and second filtered light signals within the first and second wavebands respectively. 
 
     
     
         15 . The method as claimed in any one of  claims 1  to  14  wherein the product is a meat sample or carcass, and a main or more abundant substance of the product is any of or any combination of collagen, tissue and fat, and substance(s) or contaminant(s) to be determined is any of or any combination of fecal residue, fat, porphyrin, collagen and bacteria. 
     
     
         16 . The method as claimed in any one of  claims 10  to  15  wherein the excitation wavelength is between approximately 350 nm to 650 nm. 
     
     
         17 . The method as claimed in any one of  claims 10  to  16  wherein the excitation wavelength is approximately 365 nm, 405 nm, 450 nm, 532 nm or 650 nm. 
     
     
         18 . The method as claimed in any one of  claims 10  to  17  wherein the excitation wavelength is 450 nm. 
     
     
         19 . The method as claimed in any one of  claims 1  to  18  wherein the first waveband is between approximately 625 nm and 850 nm. 
     
     
         20 . The method as claimed in any one of  claims 1  to  19  wherein the second waveband is between approximately 666 nm and 676 nm. 
     
     
         21 . The method as claimed in any one of  claims 1  to  18  wherein the first waveband is approximately 450-800 nm and the second waveband is approximately 580-800 nm. 
     
     
         22 . A method for determining or predicting the amount of one or more substances or contaminants in or on an illuminated product, the method comprising the steps of:
 receiving at least one signal indicative of intensity of light emitted from the product across a waveband, and   determining or predicting the amount of each, or at least one, of the one or more substances or contaminants in or on the product by separating a portion of the emitted signal relating to the substance or contaminant from the overall signal emitted from the product based on fluorescent behaviour of the substance or contaminant in isolation from the product and/or based on the fluorescent behaviour of the product or a main or more abundant substance of the product in isolation from the substances or contaminants (hereinafter referred to as isolated product).   
     
     
         23 . The method as claimed in  claim 22  wherein the step of receiving at least one signal comprises:
 receiving a first signal indicative of intensity of light emitted from the product across a first waveband, 
 receiving a second signal indicative of intensity of light emitted from the product across a second waveband and containing one or more wavelengths associated with the fluorescent properties of the contaminants or substances to be detected, 
 
     
     
         24 . The method as claimed in either  claim 22  or  claim 23  wherein the second waveband is within the first waveband. 
     
     
         25 . The method as claimed in either  claim 22  or  claim 23  wherein the second waveband is outside the first waveband. 
     
     
         26 . The method as claimed in any one of  claims 22  to  26  wherein the step of determining or predicting the value indicative of the amount of the substance or contaminant comprises separating from the first signal a portion of the signal relating to the substance or contaminant based on: the second signal, the fluorescent behaviour of the substance or contaminant in isolation from the product and the fluorescent behaviour of the isolated product. 
     
     
         27 . The method as claimed in any one of  claims 22  to  26  wherein the method further comprises determining or predicting a value indicative of an amount of a main or more abundant substance of the product by separating from the first signal a portion of the signal relating to the main substance based on: the second signal, the fluorescent behaviour of each isolated substance or contaminant and the fluorescent behaviour of the isolated product. 
     
     
         28 . A method for determining fecal contamination in a product comprising the steps of:
 determining the amount of a contaminant in or on the product in accordance with the method as claimed in any one of  claims 1  to  27 , and   determining fecal contamination when the amount of the contaminant exceeds a predetermined threshold or thresholds.   
     
     
         29 . The method as claimed in  claim 28  wherein the method further comprises outputting a signal indicative of fecal contamination when the amount of the contaminant exceeds the predetermined threshold or thresholds. 
     
     
         30 . The method as claimed in either  claim 28  or  claim 29  including determining the amount of the contaminant based on either a value, I c , indicative of the amount of the substance or contaminant in or on the product, or a parameter, R C , indicative of the deviation of the signals associated with the product from the signals associated with the isolated product, or a combination of both. 
     
     
         31 . The method as claimed in any one of  claims 28  to  30  wherein the step of determining fecal contamination comprises determining contamination when I C  exceeds a predetermined I threshold, when R c  exceeds a predetermined R threshold, or when both I C  and R C  exceed both the I threshold and the R threshold respectively. 
     
     
         32 . A device for determining an amount of one or more substances or contaminations in or on a product, the device comprising:
 a memory component for storing data indicative of predetermined information relating to fluorescence behaviour of a same or similar product or a main or more abundant substance of the product isolated from a substance or contaminant (hereinafter referred to as isolated product) and/or relating to the fluorescence behaviour of each of the one or more substances or contaminants isolated from the product, and   a processor configured to:   receive a first signal indicative of intensity of light emitted from the product across a first waveband,   receive a second signal indicative of intensity of light emitted from the product across a second waveband and containing one or more wavelengths associated with the fluorescent properties of the contaminants or substances to be detected,   determine or predict a value indicative of an amount of each, or at least one, of the substance or contaminant, in or on the product from the first and second signals and from the predetermined information.   
     
     
         33 . The device as claimed in  claim 32  wherein the second waveband is within the first waveband. 
     
     
         34 . The device as claimed in  claim 32  wherein the second waveband is outside the first waveband. 
     
     
         35 . The device as claimed in any one of  claims 32  to  34  wherein the device further comprises a light source for generating a beam of light. 
     
     
         36 . The device as claimed in any one of  claims 32  to  35  wherein the device further comprises:
 a first band pass filter arranged to filter a light beam and having a first operative waveband associated with the first waveband, and 
 a second band pass filter arranged to filter a light beam and having a second operative waveband associated with the second waveband. 
 
     
     
         37 . The device as claimed in  claim 36  further comprising first and second photomultiplier tubes adjacent to the first and second filters respectively, for receiving filtered light beams from the first and second filters and outputting the first and second signals indicative of light intensities to the processor respectively. 
     
     
         38 . The device as claimed in either  claim 36  or  claim 37  wherein further comprising an optical fibre cable coupled to the light source for transmitting light out of the device and onto the product and for transmitted light emitted from the product to the first and second filters. 
     
     
         39 . The device as claimed in  claim 38  wherein the cable is optically coupled to a lens element adjacent the product. 
     
     
         40 . The device as claimed in  claim 39  wherein the lens is arranged to yield an excitation light beam from a central excitation fibre of the fibre cable onto a region of interest on the product in one direction and yield an emission light beam emitted from the product into emission fibres of the fibre cable in an opposite direction. 
     
     
         41 . The device as claimed in any one of  claims 35  to  40  further comprising a camera lens configured to receive light emitted from the product in response to excitation from the light source and output an image signal. 
     
     
         42 . The device as claimed in  claim 41  wherein further comprising a beam splitter configured to divide the image signal into a first and second channel. 
     
     
         43 . The device as claimed in  claim 42  wherein further comprising a first image sensor with a first optical filter associated with the first channel and a second image sensor with a second optical filter associated with the second channel, wherein a first optical filter is arranged to filter the output image signal based on a first operative waveband, and the second optical filter is arranged to filter the output image signal based on a second operative waveband, the second waveband being within the first waveband. 
     
     
         44 . A system for determining an amount of one or more substances or contaminations in or on a product, the system comprising:
 a light source for illuminating the product with excitation light, and   a light detector for determining the amount of one or more substances or contaminations in or on a product, the detector having:   a memory component for storing data indicative of predetermined information relating to fluorescence behaviour of a same or similar product or a main or more abundant substance of the product isolated from a substance or contaminant (hereinafter referred to as isolated product) and/or relating to the fluorescence behaviour of each of the one or more substances or contaminants isolated from the product, and   a processor configured to:   receive a first signal indicative of intensity of light emitted from the product across a first waveband,   receive a second signal indicative of intensity of light emitted from the product across a second waveband and containing one or more wavelengths associated with the fluorescent properties of the contaminants or substances to be detected,   determine or predict a value indicative of an amount of each, or at least one, of the substance or contaminant, in or on the product from the first and second signals and from the predetermined information.   
     
     
         45 . The system as claimed in  claim 44  wherein the second waveband is within the first waveband. 
     
     
         46 . The system as claimed in  claim 44  wherein the second waveband is outside the first waveband.