Patent Description:
Lasers are commonly used in observation and targeting applications, for example, in guiding laser-guided munitions or weapons to a target. Targeting systems may observe and detect the range of an object. Targeting systems may also designate a target for detection by another weapon system in order to deliver the weapon to the designated target. Such targeting systems generally use a set of devices to perform the operations described with precision, for example, global positioning systems, observation binoculars, laser rangefinders, digital magnetic compasses, and laser designators. <CIT> <CIT> and <CIT> disclose various devices, systems, and methods related to laser targeting.

Integrating multiple devices into a common device can be challenging. For example, heat generated by electronics associated with one device may influence the operation of another device, and must be removed from the system in order to allow operation of each of the devices incorporated in the system. The devices incorporated in the system can also require considerable amounts of electrical power, requiring an operator to frequently change batteries and/or provide power from an external power source. Components of each separate device must also be ruggedized in a system arrangement to ensure availability of the devices in difficult operating environments.

Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved targeting systems and methods. The present disclosure provides a solution for this need.

According to a first aspect of the present invention, an imaging method is provided as claimed in claim <NUM>.

According to a second aspect of the present invention, a handheld imaging system is provided as claimed in claim <NUM>.

An imaging method includes receiving electromagnetic radiation at a focal plane array of a handheld device. The electromagnetic radiation is processed within the handheld device, and visible images are displayed on the handheld device. The displayed visible images are indicative of a scene, and include a designator and a designator identifier when a high frequency laser pulse is in the scene. The designator and designator identifier represent the high frequency pulsed electromagnetic radiation received by the focal plane array when a high frequency pulse is present in the scene.

The electromagnetic radiation is converted into image data and high frequency pulse data. Converting the electromagnetic radiation into image data can include converting the electromagnetic radiation into pixel photocurrents. The image data is representative of integrated pixel photocurrents during a first exposure period. Converting the electromagnetic radiation into high frequency pulse data can include converting the electromagnetic radiation into pixel voltages. The high frequency pulse data is representative of presence, or lack of presence, of a high frequency laser pulse in the pixel voltages during a second exposure period.

The image data and the high frequency pulse data are acquired from a single focal plane array with a single objective lens. The second exposure period is shorter than the first exposure period. The image data and the high frequency pulse data can be acquired from electromagnetic radiation within a common waveband.

It is contemplated that, in accordance with certain embodiments, the common waveband can be an infrared waveband, a thermal waveband, a short-wavelength infrared radiation (SWIR) waveband, or a near-infrared radiation (NIR) waveband. The common waveband can be between about <NUM> and about <NUM> microns. The designator is inserted into the visible image when the high frequency pulse data indicates presence of pulsed laser illumination in the scene. The designator can be inserted in the visible image in relation to location of pulsed laser illumination of the scene. A designator identifier can be inserted into the visible image. The designator identifier is inserted into the visible image when the high frequency pulse data indicates presence of pulsed laser illumination in the scene corresponding to a predetermined pulse repetition frequency (PRF) code.

A handheld imaging system according to the invention is defined in claim <NUM>. The handheld imaging system includes a housing, a focal plane array disposed in the housing, and a display disposed in the housing. A processor is in operable communication with the focal plane array and the display, the processor being configured to process image data and high frequency laser pulse data received from the focal plane array and control the display to show visible images of the scene on the display. When the high frequency laser pulse data indicates that high frequency pulsed laser illumination is present in the scene, the processor inserts a designator into the visible image. When the high frequency laser pulse data indicates that high frequency pulsed laser illumination present in the scene has a PRF code, the processor inserts a designator identifier into the visible image.

In certain embodiments, the focal plane array can include a photodetector array arranged to receive electromagnetic radiation and convert the electromagnetic radiation into a photocurrent. A readout integrated circuit can be connected to the photodetector array to form the focal plane array. The readout integrated circuit can be arranged to convert the photocurrent into two voltages. The first voltage can be representative of the scene, and can be converted into image data. The second voltage can be representative of high frequency pulsed laser illumination present in the scene, and can be converted into high frequency pulse data.

In accordance with certain embodiments, the processor can be in operable communication with the focal plane array through first and second channels. The first channel can provide the image data. The image data includes integrated photocurrents from pixels of the focal plane array integrated over a first exposure period. The second channel can provide the high frequency pulse data. The high frequency pulse data includes voltages from pixels of the focal plane array over a second exposure period.

It is also contemplated that, in accordance with certain embodiments, the processor can be in communication with a memory. The memory can be non-transitory machine readable medium having instructions recorded on it that, when read by the processor, cause the processor to execute the above described methods.

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of an imaging system in accordance with the disclosure is shown in <FIG> and is designated generally by reference character <NUM>. Other embodiments of imaging systems and imaging methods in accordance with the disclosure, or aspects thereof, are provided in <FIG>, as will be described. The systems and methods described herein can be used to display visible images including designators and designator identifiers in a handheld short-wavelength infrared radiation (SWIR) imaging system, through the present disclosure is not limited to handheld devices or to SWIR imaging systems in general.

Referring now to <FIG>, imaging system <NUM> is shown. Imaging system <NUM> is arranged to receive electromagnetic radiation <NUM> from a scene <NUM> and display a visible image (shown in <FIG>) of the scene. It is contemplated that electromagnetic radiation <NUM> used to construct the visible image be electromagnetic radiation within thermal waveband band, a near-infrared radiation (NIR) waveband, a SWIR waveband, and/or electromagnetic radiation within a waveband between about <NUM>. <NUM> and about <NUM> microns. Electromagnetic radiation <NUM> can include pulsed electromagnetic radiation <NUM> and/or <NUM> present in scene <NUM> from one or more pulsed laser illuminators, e.g., a first laser source <NUM> and/or one or more second laser sources <NUM>. The pulsed electromagnetic radiation, e.g., pulsed electromagnetic radiation <NUM>, can include a pulse repetition frequency (PRF) code associated with a particular pulsed laser source illuminator, e.g., first laser source <NUM>.

With reference to <FIG>, imaging system <NUM> is shown. Imaging system <NUM> includes a lens <NUM>, a focal plane array <NUM>, a controller <NUM>, and a display <NUM>. Lens <NUM> is optically coupled to focal plane array <NUM> and is configured to collect electromagnetic radiation <NUM> (shown in <FIG>) and provide the electromagnetic radiation <NUM> to a surface <NUM> of focal plane array <NUM>.

Focal plane array <NUM> includes a photodetector array <NUM> with a surface <NUM> and a readout integrated circuit <NUM>. Photodetector array <NUM> has plurality of photodiode devices arranged in a plane orthogonal to an optical axis A extending between lens <NUM> and photodetector array <NUM> configured to convert incident electromagnetic radiation <NUM> (shown in <FIG> ) into pixel photocurrents, the pixel photocurrents corresponding to an intensity of short-wavelength infrared electromagnetic radiation incident upon respective photodiode.

Readout integrated circuit <NUM> is connected to photodetector array <NUM>. Readout integrated circuit <NUM> has a plurality of pixel cells corresponding to the photodiodes of the photodetector array and is configured to convert photocurrents generated within photodetector array <NUM> into image data and high frequency pulse data. In this respect readout integrated circuit <NUM> converts photocurrents generated within respective photodiodes of photodetector array <NUM> into pixel voltages by integrating the photocurrents over a first exposure period to form image data <NUM>, which readout integrated circuit <NUM> provides to controller <NUM> over a link <NUM>. Readout integrated circuit <NUM> also converts photocurrents generated within photodiodes of photodetector array <NUM> into pixel voltages, which are surveyed over a second exposure period to generate high frequency pulse data <NUM>, which readout integrated circuit <NUM> also provides to controller <NUM> over link <NUM>.

Link <NUM> has a first channel for image data <NUM> and a second channel for high frequency pulse data <NUM>, connecting readout integrated circuit <NUM> with controller <NUM>. It is contemplated that readout integrated circuit <NUM> can provide image data to controller <NUM> using a first exposure period and high frequency pulse data to controller using a second exposure period (show with a dashed/dotted line) that is equal to the first exposure period (shown in solid line), a second exposure period (shown in dashed line) that is longer than the first exposure period, or a second exposure period (shown in dotted line) that is shorter than the first exposure period.

Controller <NUM> includes a processor <NUM>, and interface <NUM>, and internal bus <NUM>, and a memory <NUM>. Processor <NUM> may include one or more of an application-specific integrated circuit (ASIC) or field-programmable gate array (FPGA) device, and is communicative with readout integrated circuit <NUM> via interface <NUM> and link <NUM>. Processor <NUM> is also communicative with memory <NUM> through internal bus <NUM>. Memory <NUM> includes a non-transitory machine readable medium having a plurality of program modules <NUM> recorded thereon. Program modules <NUM> have instructions that, when read by processor <NUM>, cause processor <NUM> to undertake certain actions. In this respect the instructions cause processor <NUM> to acquire image data <NUM> within the first exposure period and high frequency pulse data <NUM> within the second exposure period.

With reference to <FIG> and <FIG>, the instructions cause processor <NUM> to construct a visible image <NUM> using the image data, which processor <NUM> causes to be displayed on display <NUM>. When the high frequency pulse data indicates presence of high frequency laser pulse illumination in scene <NUM> (shown in <FIG>), the instructions further cause processor <NUM> to generate a designator <NUM>, which processor <NUM> causes designator <NUM> to be inserted within visible image <NUM> on display <NUM>. When the high frequency pulse data indicates presence of high frequency laser pulse illumination in scene <NUM> which is associated with a predetermined PRF code, which processor <NUM> causes a designator identifier <NUM> to be inserted within visible image <NUM> on display <NUM>. Designator <NUM> and/or designator identifier <NUM> can be inserted within visible image <NUM> in a location corresponding to the location of the high frequency laser pulse illumination within scene <NUM>.

With reference to <FIG>, display <NUM> is fixed relative to single focal plane array <NUM> within a common housing <NUM>. It is contemplated that housing <NUM> can be arranged as handheld, weapon-mounted, or helmet-mounted observation device. Display <NUM> can be, in accordance with certain embodiments, an eyepiece for presenting to a user a visible image of a scene acquired using SWIR image data, a designator in the visible image corresponding with a laser designator in the scene, and a designator identifier associated with designator and corresponding to a PRF code carried by the designator. As will be appreciated by those of skill in the art, generating a visible image and concurrently inserting and decoding a designator with a single focal plane array allows for imaging system to be relatively small and compact, and comparatively indicated by the size of imaging system <NUM> in relation to the coin shown in <FIG>.

With continuing reference to <FIG>, memory <NUM> may include any combination of one or more computer readable medium(s). Memory <NUM> may be a computer readable signal medium or a computer readable storage medium. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages.

Aspects of the present disclosure are described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention.

A related imaging method includes receiving electromagnetic radiation, e.g., electromagnetic radiation <NUM> (shown in <FIG>) at a focal plane array, e.g., focal plane array <NUM> (shown in <FIG>), of a handheld device, e.g., imaging system <NUM> (shown in <FIG>). The electromagnetic radiation is processed within the handheld device, and visible images, e.g., visible image <NUM> (shown in <FIG>) are displayed on the handheld device. The displayed visible images are indicative of a scene, e.g., scene <NUM> (shown in <FIG>). A designator, e.g., designator <NUM> (shown in <FIG>), can be inserted into the scene when a high frequency laser pulse is in the scene. A designator identifier, e.g., designator identifier <NUM> (shown in <FIG>), can be inserted into the scene when the high frequency laser pulse is modulated with a PRF code.

The electromagnetic radiation is converted into image data, e.g., image data <NUM> (shown in <FIG>), and high frequency pulse data, e.g., high frequency pulse data <NUM> (shown in <FIG>). Converting the electromagnetic radiation into image data includes converting the electromagnetic radiation into pixel voltages, which is representative of integrated pixel photocurrents during a first exposure period (shown in solid line in <FIG>). The image data and the high frequency pulse data can be converted from electromagnetic radiation acquired by the focal plane array from within a common waveband, e.g., from a SWIR waveband or a waveband between <NUM> and <NUM> microns.

Converting the electromagnetic radiation into high frequency pulse data includes converting the electromagnetic radiation into pixel voltages. The high frequency pulse data is representative of presence, or lack of presence, of a high frequency laser pulse in the pixel voltages during a second exposure period. In certain embodiments the high frequency pulse data is a binary bitmap of the scene with high bits and low bits. High bits within the bitmap can indicate the presence of designator high frequency pules at the bitmap location. Low bits within the bitmap can indicate the lack of presence within at bitmap locations.

The image data and the high frequency pulse data can be acquired from a common focal plane array, e.g., focal plane array <NUM> (shown in <FIG>). The second exposure period can have a duration (shown in dotted/dashed line in <FIG>) that is the same duration as the first exposure period. The second exposure period can have a duration that is different than duration of the first exposure period. The second exposure period can have a duration (shown in dotted line in <FIG>) that is shorter than the first exposure period. The second exposure period can have a duration (shown in dashed line in <FIG>) that is longer than the first exposure period.

The designator can be inserted into the visible image when the high frequency pulse data indicates presence of pulsed laser illumination in the scene. The designator can be inserted in the visible image in relation to location of pulsed laser illumination of the scene, for example, in registration with a location wherein pulsed laser illumination appeared during the second time period. A designator identifier can be inserted into the visible image. The designator identifier can be inserted into the visible image when the high frequency pulse data indicates presence of pulsed laser illumination in the scene corresponding to a predetermined PRF code.

The systems and methods described herein, therefore, disclose a handheld system that creates a short-wavelength infrared radiation image with the ability to see lasers with wavelengths between <NUM> microns and <NUM> microns. The techniques described above are customizable for particular applications, and may be used for <NUM> nanometer pulsed lasers and/or <NUM> nanometer pulsed lasers. Moreover, the handheld unit can have a single photodetector array and a single objective lens to capture SWIR imagery, create imagery that is transferrable to a visible display for creating a visible representation of the SWIR image, as well as show a visible location of the laser energy within the visible image, and additionally display a PRF code associated with the visible location of the laser image in the visible image.

The foregoing description has been directed to specific embodiments. It will be apparent, however, that other variations and modifications may be made to the described embodiments, with the attainment of some or all of their advantages. For instance, it is expressly contemplated that the components and/or elements described herein can be implemented as software being stored on a tangible (non-transitory) computer-readable medium (e.g., one or more media such as disks/CDs/RAM/EEPROM/etc.) having program instructions executing on a computer, hardware, firmware, or a combination thereof. Accordingly this description is to be taken only by way of example and not to otherwise limit the scope of the embodiments herein. Therefore, it is the object of the appended claims to cover all such variations and modifications as come within the true spirit and scope of the embodiments herein.

Claim 1:
An imaging method, comprising:
receiving electromagnetic radiation (<NUM>) at a focal plane array (<NUM>) of a handheld device (<NUM>);
processing the received electromagnetic radiation within the handheld device; and
displaying visible images (<NUM>) on the handheld device indicative of a scene (<NUM>) including a designator (<NUM>) and a designator identifier (<NUM>), the designator and designator identifier being representative of pulsed electromagnetic radiation (<NUM>, <NUM>) received by the focal plane array; the method characterised by
the step of processing the received electromagnetic radiation comprising converting the electromagnetic radiation into image data (<NUM>) and into high frequency pulse data (<NUM>) using the focal plane array (<NUM>) as a single focal plane array with a single objective lens;
wherein the image data includes pixel photocurrents integrated over a first exposure period;
wherein the high frequency pulse data includes voltages representative of presence, or lack of presence, of high frequency laser illumination within a second exposure period;
wherein the second exposure interval has a shorter duration than the first exposure interval; and
wherein the method further comprises:
constructing a visible image (<NUM>) using the image data (<NUM>); and
generating the designator (<NUM>) and/or the designator (<NUM>) identifier using the high frequency pulse data (<NUM>), wherein the designator (<NUM>) is inserted into the visible image (<NUM>) when the high frequency pulse data (<NUM>) indicates the presence of pulsed laser illumination, and the designator identifier (<NUM>) is inserted into the visible image (<NUM>) when the high frequency pulse data (<NUM>) corresponds to a predetermined pulse repetition frequency code.