Laser pulse shape detection using frequency characterization
A method includes receiving a plurality of laser pulses as a pulse train on a plurality of imaging sensor pixels in an array of pixels. For each pixel in the array of pixels, the method includes receiving a respective one of the laser pulse trains, and scanning the pixels response across a range of frequencies with a bandpass filter to determine pulse shape characteristics of the respective one of the laser pulse trains. The method includes filtering out all of the laser pulse trains that do not fit a predetermined pulse shape characteristic for a true target designation pulse train, and physically adjusting trajectory of a physical resource toward a target based on location on the imaging sensor of one or more pixels receiving a laser pulse train that fits the predetermined pulse shape characteristic for the true target designation pulse train.
1 . A method comprising:
determining a pulse repetition frequency (PRF) of a train of pulses generated by a laser designator;
coordinating a capture of a sequence of images with the PRF so as to capture a single pulse of the train of pulses within each of the sequence of images captured, the images captured,
via an imaging sensor with a two-dimensional array of pixels, each located at a corresponding pixel location within the two-dimensional array of pixels;
globally configuring band-pass filtering, by an ROIC, of temporal signals generated by each of the two-dimensional array of pixels for each of the sequence of images captured, thereby generating filtered pulse data;
determining a temporal pulse shape corresponding to each of the two-dimensional array of pixels using the filtered pulse data obtained for the sequence of images captured;
identifying one or more pixels the two-dimensional array of pixels corresponding to a predetermined temporal pulse shape characteristic of a true target; and
physically adjusting trajectory of a guided munition toward the true target based on the pixel locations of the one or more pixels having the predetermined temporal pulse shape characteristic of the true target.
2 . The method as recited in claim 1 , further comprising:
globally configuring intensity thresholding, by the ROIC, of the temporal signals generated by each of the two-dimensional array of pixels during the sequence of images captured.
3 . The method as recited in claim 1 , further comprising:
reading in the filtered pulse data from the ROIC for each of the sequence of images captured.
4 . The method as recited in claim 1 , wherein the sequence of images are captured at a frequency on the order of 1 KHz.
5 . The method as recited in claim 1 , wherein globally configuring band-pass filtering, by an ROIC, of temporal signals generated by each of the two-dimensional array of pixels during the sequence of images captured includes changing a center frequency of the band-pass filtering for each of the sequence of temporal windows of image capture.
6 . A system comprising:
an imaging sensor with a two-dimensional array of pixels, each located at a corresponding pixel location within the two-dimensional array of pixels;
a read out integrated circuit (ROIC) including globally configurable band-pass filtering of temporal signals generated by each of the two-dimensional array of pixels during a capture of an image, thereby generating filtered pulse data; and
a processor operatively connected to the ROIC, wherein the processor includes machine readable instructions configured to cause the processor to:
control settings of the ROIC to globally configure the band-pass filtering of the temporal signals generated by each of the two-dimensional array of pixels during each of a sequence of images captured, each of the sequence of images captured timed to permit capture of a single pulse of a train of pulses generated by a laser designator;
determine a temporal pulse shape corresponding to each of the two-dimensional array of pixels using the filtered pulse data obtained for the sequence of images captured;
identify one or more pixels of the two-dimensional array of pixels corresponding to a predetermined temporal pulse shape characteristic of a true target; and
output control signals for physically adjusting trajectory of a guided munition toward the true target based on the pixel locations of the one or more pixels having the predetermined temporal pulse shape characteristic of the true target.
7 . The system as recited in claim 6 , further comprising the guided munition, wherein the imaging senor, the ROIC, and the processor are onboard the guided munition.
8 . The system as recited in claim 7 , further comprising optics aligned to focus images of a scene and laser pulse trains onto the array of pixels.
9 . The system as recited in claim 6 , wherein the ROIC includes globally configurable intensity thresholding of the temporal signals generated by each of the two-dimensional array of pixels during a temporal window of image capture, and the machine readable instructions are further configured to cause the processor to control settings of the ROIC to globally configure the intensity thresholding of the temporal signals generated by each of the two-dimensional array of pixels during each of a sequence of images captured.
10 . The system as recited in claim 9 , wherein the machine readable instructions are configured to cause the processor to read in the filtered pulse data from the ROIC for each of the sequence of images captured.
11 . The system as recited in claim 10 , wherein the machine readable instructions are configured to cause the processor to cause the ROIC to change a center frequency of the band-pass filtering for each of the sequence of images captured.