Gunshot detection system and method

Abstract

A device and a method for use in detection of a muzzle flash event is described. The device can include a Photo Detector Array (PDA), sensitive in at least a portion of the NIR and SWIR spectrum, and a filter of electromagnetic radiation selectively passing in this portion a spectral range of low atmospheric transmission, the PDA has an integration time shorter than a duration of the muzzle flash event.

1 . A method for use in detection of a muzzle flash event, the method comprising sensing electromagnetic radiation by a Photo Detector Array (PDA), sensitive in at least a portion of the NIR and SWIR spectrum, wherein said electromagnetic radiation passed through a filter of electromagnetic radiation configured and operable for selectively passing, in said at least portion of the NIR and SWIR spectrum, a spectral range of low atmospheric transmission, said sensing having an integration time shorter than a duration of the muzzle flash event. 
     
     
         2 . The method of  claim 1 , wherein said time is shorter than 10 −2  s. 
     
     
         3 - 62 . (canceled) 
     
     
         63 . The method of  claim 1 , the utilized sensing at least for a part being performed within the NIR spectrum. 
     
     
         64 . The method of  claim 1 , the utilized sensing at least for a part being performed within the SWIR spectrum. 
     
     
         65 . The method of  claim 1 , the PDA having a sensitivity maximum at a wavelength longer than 3 microns and a sensitivity cut-off at a wavelength shorter than 5 microns. 
     
     
         66 . The method of  claim 1 , the PDA having a sensitivity maximum at a wavelength shorter than 3 microns. 
     
     
         67 . The method of  claim 66 , the PDA having a sensitivity cut-off at a wavelength shorter than 5 microns. 
     
     
         68 . The method of  claim 66 , the PDA having a sensitivity cut-off at a wavelength between 1.4 μm and 1.65 μm. 
     
     
         69 . The method of  claim 66 , the PDA having a sensitivity cut-off at a wavelength 1.65 μm and 1.8 μm. 
     
     
         70 . The method of  claim 66 , the PDA having a sensitivity cut-off at a wavelength between 1.8 μm and 2.5 μm. 
     
     
         71 . The method of  claim 1 , the PDA having a sensitivity maximum at a wavelength longer than 0.75 microns. 
     
     
         72 . The method of  claim 1 , the PDA having a region of a predominant sensitivity fully within the NIR/SWIR range, said region being a region where the sensitivity is higher than 20% of a maximum PDA's sensitivity. 
     
     
         73 . The method of  claim 72 , wherein the predominant sensitivity is higher than 35% of a maximum PDA's sensitivity. 
     
     
         74 . The method of  claim 72 , wherein the predominant sensitivity is higher than 50% of the maximum PDA's sensitivity. 
     
     
         75 . The method of  claim 72 , wherein the predominant sensitivity is higher than 70% of a maximum PDA's sensitivity. 
     
     
         76 - 85 . (canceled) 
     
     
         86 . The method of  claim 1 , the sensing being substantially within a range of low atmospheric light transmission at least partially including the trough situated around 1.15 μm (micron). 
     
     
         87 . The method of  claim 1 , the sensing being substantially within a range of low atmospheric light transmission at least partially including a trough extending from 1.34 μm to 1.50 μm. 
     
     
         88 . The method of  claim 1 , the sensing being substantially within a range of low atmospheric light transmission at least partially including a trough extending from 1.80 μm to 2.00 μm. 
     
     
         89 . The method of  claim 1 , the sensing being substantially within a range of low atmospheric light transmission at least partially including a trough extending from 2.50 μm to 2.90 μm. 
     
     
         90 . The method of  claim 1 , the PDA being a CMOS PDA. 
     
     
         91 . The method of  claim 1 , the PDA being an intracavity PDA. 
     
     
         92 . The method of  claim 1 , an integration time of the sensing being between 10 −2  s and 5.0·10 −3  s. 
     
     
         93 . The method of  claim 1 , an integration time of the sensing being between 5.0·10 −3  s and 2.0·10 −3  s. 
     
     
         94 . The method of  claim 1 , an integration time of the sensing being between 2.0·10 −3  s and 5.0·10 −4  s. 
     
     
         95 . The method of  1 , an integration time of the sensing being between 5.0·10 −4  s and 10 −4  s. 
     
     
         96 . (canceled) 
     
     
         97 . A device for use in detection of a muzzle flash event, the device comprising a Photo Detector Array (PDA), sensitive in at least a portion of the NIR and SWIR spectrum, and a filter of electromagnetic radiation selectively passing in said portion a spectral range of low atmospheric transmission, the PDA having an integration time shorter than a duration of the muzzle flash event. 
     
     
         98 . The of claim  7 , wherein said integration time is shorter than 10 −2  s. 
     
     
         99 - 163 . (canceled) 
     
     
         164 . The device of  claim 97 , the PDA at least partially being sensitive within the NIR spectrum. 
     
     
         165 . The device of any one of  claim 97 , the PDA at least partially being sensitive within the SWIR spectrum. 
     
     
         166 . The device of any one of  claim 97 , the PDA having a sensitivity maximum at a wavelength longer than 3 microns and a sensitivity cut-off at a wavelength shorter than 5 microns. 
     
     
         167 . The device of  claim 97 , the PDA having a sensitivity maximum at a wavelength shorter than 3 microns. 
     
     
         168 . The device of  claim 167 , the PDA having a sensitivity cut-off at a wavelength shorter than 5 microns. 
     
     
         169 . The device of  claim 168 , the PDA having a sensitivity cut-off at a wavelength between 1.4 μm and 1.65 μm. 
     
     
         170 . The device of  claim 168 , the PDA having a sensitivity cut-off at a wavelength 1.65 μm and 1.8 μm. 
     
     
         171 . The device of  claim 168 , the PDA having a sensitivity cut-off at a wavelength between 1.8 μm and 2.5 μm. 
     
     
         172 . The device of any one of  claim 97 , the PDA having a sensitivity maximum at a wavelength longer than 0.75 microns. 
     
     
         173 . The device of  claim 97 , the PDA having a region of a predominant sensitivity fully within the NIR/SWIR range, said region being a region where the sensitivity is higher than 20% of a maximum PDA's sensitivity. 
     
     
         174 . The device of  claim 173 , wherein the predominant sensitivity is higher than 35% of a maximum PDA's sensitivity. 
     
     
         175 . The device of  claim 173 , wherein the predominant sensitivity is higher than 50% of the maximum PDA's sensitivity. 
     
     
         176 . The device of  claim 173 , wherein the predominant sensitivity is higher than 70% of a maximum PDA's sensitivity. 
     
     
         177 - 186 . (canceled) 
     
     
         187 . The device of  claim 97 , the device adapted to sense electromagnetic radiation substantially within a range of low atmospheric light transmission at least partially including the trough situated around 1.15 μm (micron). 
     
     
         188 . The device of  claim 97 , the device adapted to sense electromagnetic radiation substantially within a range of low atmospheric light transmission at least partially including a trough extending from 1.34 μm to 1.50 μm. 
     
     
         189 . The device of  claim 97 , the device adapted to sense electromagnetic radiation substantially within a range of low atmospheric light transmission at least partially including a trough extending from 1.80 μm to 2.00 μm. 
     
     
         190 . The device of  claim 97 , the device adapted to sense electromagnetic radiation substantially within a range of low atmospheric light transmission at least partially including a trough extending from 2.50 μm to 2.90 μm. 
     
     
         191 . The device of  claim 97 , the PDA being a CMOS PDA. 
     
     
         192 . The device of  claim 97 , the PDA being an intracavity PDA. 
     
     
         193 . The device of  claim 97 , an integration time of the PDA sensing being between 10 −2  s and 5.0·10 −3  s. 
     
     
         194 . The device of  claim 97 , an integration time of the PDA sensing being between 5.0·10 −3  s and 2.0·10 −3  s. 
     
     
         195 . The device of  claim 97 , an integration time of the PDA sensing being between 2.0·10 −3  s and 5.0·10 −4  s. 
     
     
         196 . The device of  claim 97 , an integration time of the PDA sensing being between 5.0·10 −4  s and 10 −4  s. 
     
     
         197 . (canceled) 
     
     
         198 . (canceled) 
     
     
         199 . (canceled) 
     
     
         200 . The device of  claim 97 , wherein said filter passes less than 50% of energy of wavelengths being outside said spectral range of low atmospheric transmission and sensed by the PDA. 
     
     
         201 . The device of  claim 97 , wherein said filter passes less than 25% of energy of wavelengths being outside said spectral range of low atmospheric transmission and sensed by the PDA. 
     
     
         202 . The device of  claim 97 , wherein said filter passes less than 10% of energy of wavelengths being outside said spectral range of low atmospheric transmission and sensed by the PDA. 
     
     
         203 . The device of  claim 97 , wherein said filter passes less than 2% of energy of wavelengths being outside said spectral range of low atmospheric transmission and sensed by the PDA. 
     
     
         204 . The device of  claim 200  having for at least one wavelength of said spectral range a sensitivity between 50% and 75% of the sensitivity of the PDA. 
     
     
         205 . The device of  claim 200  having for at least one wavelength of said spectral range a sensitivity larger than 75% of the sensitivity of the PDA. 
     
     
         206 . A processing unit for use in detection of a muzzle flash event, said processing unit being adapted to process pixel signals originating from a PDA and to generate substantially likelihoods of muzzle flash detection for pixels of the PDA, the processing unit comprising a multiplexer dividing the pixel signals between at least two branches. 
     
     
         207 - 209 . (canceled)