Patent Application
20130148104
Targeting systems and surveillance systems are designed to identify intended targets. Target identification is complicated by the fact that one or both of the targeting system and the target may be moving (e.g., airborne), and because a target typically changes in time and space. Consequently, actual targets have spatial features (e.g., shape) and spectral features (e.g., color) that change dynamically. Development of targeting and surveillance systems can be problematic due to the difficulty in simulating targets to test the system's ability to correctly identify targets. Current target simulators are typically not accurate in terms of spatial content and spectral content.
This document relates generally to targeting and surveillance systems and, in particular, to simulating target objects.
A method example includes receiving incident light onto a surface including movable micro-mirrors, and arranging one or more of the micro-mirrors to project a spatial image using the incident light and to generate spectral content for the formed spatial image. The spectral content includes light having one or more wavelengths outside a range of wavelengths for visible light. The method also includes extracting spectral image information from the spectral content, and further arranging one or more of the micro-mirrors using the extracted spectral image information to adjust the generated spectral content based on the extracted spectral image information.
A system example includes a micro-minor device including a surface having a plurality of micro-mirrors movable to reflect light incident to the micro-mirrors in at least a first direction and a second direction, a control circuit configured to arrange the micro-minors to project a spatial image using the incident light and to generate spectral content for the formed spatial image, and a spectrometer circuit configured to extract spectral image information from the generated spectral content and provide the spectral image information to the control circuit. The spectral content includes light having one or more wavelengths outside a range of wavelengths for visible light, and the control circuit is configured to rearrange one or more micro-minors of the micro-minor device to adjust spectral content based on the extracted spectral image information.
This section is intended to provide an overview of subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application.
In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.
This document discusses systems and methods for simulating targets to test the ability of a targeting system or portions of a targeting system to recognize targets. Target objects can be identified using spatial features of the object (e.g., the physical shape of the target) and using spectral features (e.g., as object color or a heat signature of the target). Typically, target simulators do not model both spatial features and spectral features of virtual targets accurately. Current simulators only provide a coarse approximation of a target. For instance, one way tong wave infrared (LWIR) is simulated is by presenting a pinhole target object against blackbody radiation. This may coarsely simulate a target at a distance, but omits spatial and spectral information about a target that may be critical. Another method is to use a resistive array to simulate a target in a scene. However, the spatial and spectral information provided by the resistive array is only a coarse approximation. The resolution of the scene is poor and is difficult to control in approximating a moving target in a scene.
It is desirable to generate target models having finer detail with regard to spatial content and spectral content than a target seeker system can resolve. This would allow more accurate assessment of the target seeker system's ability to recognize a target. Spatial content can include information related to shape and size of the target. Spectral content can include image data at specific frequencies or a range of frequencies across the electromagnetic spectrum. Spectral content can include frequencies in the visible range of tight (e.g., blue, green, and red wavelengths), the ultraviolet range of light, and the infrared rang of light (e.g., near infrared, mid-infrared, and thermal infrared).
A digital micro-mirror device (DMD) includes an array of small mirrors (micro-mirrors). The arrays of micro-mirrors can be of different shapes and sizes, such as square arrays (e.g., 400×400 mirrors, 1000×1000 mirrors, etc.) or rectangle arrays (e.g., 800×600, 1024×768 mirrors, 1400×1050 mirrors, etc.). A single micro-minor may be 13 micrometers (μm) across. The minors can be individually moved (e.g., rotated ±10 to 12 degrees) to an on state and an off state. The DMD can be fabricated on a single integrated circuit (IC) and an individual micro-minor can be referred to as a pixel. A DMD can include an array of static random access memory (SRAM) with an SRAM cell allocated for each pixel. The mirrors are held in place with a bias voltage. To move the minors, the SRAM cell array is loaded with position information. The bias voltage is removed allowing the contents of an SRAM cell to move its corresponding micro-minor. The bias voltage is then reapplied to hold the micro-mirror. A device having micro-mirrors such as a DMD can be used to generate a programmable target model.
At block 210, one or more of the micro-minors are arranged to project a spatial image using the incident light and to generate spectral content for the formed spatial image. The spectral content generated includes light having one or more wavelengths outside a range of wavelengths for visible light, such as wavelengths in one or both of the ultraviolet spectrum and the infrared spectrum.
At block 215, spectral image information is extracted from the spectral content. The spectral image information can be analyzed to determine if the spectral image matches a desired spectral image for the target model. At block 220, one or more of the micro-mirrors are further arranged using the extracted spectral image information to adjust the generated spectral content based on the extracted spectral image information. In this way, feedback can be incorporated into the process of generating a target model to arrive at a desired target model.
The system 300 also includes a control circuit 315 electrically coupled to the micro-minor device 305. The control circuit 315 can include a processor such as a microprocessor, a digital signal processor, application specific integrated circuit (ASIC), or other type of processor, interpreting or executing instructions in software modules or firmware modules. The control circuit 620 includes other circuits or sub-circuits to perform the functions described. These circuits may include software, hardware, firmware or any combination thereof. Multiple functions can be performed in one or more of the circuits or sub-circuits as desired.
The control circuit 315 arranges the micro-minors to project a spatial image using the incident light and to generate spectral content for the formed spatial image. In some examples, the micro-mirror device includes a memory array circuit. The control circuit 315 can set the position of the micro-mirrors by writing the contents of the memory array. The spectral content generated includes light having one or more wavelengths outside a range of wavelengths for visible light. This allows the system 300 to generate a target model that includes spectral image information in one or more of the ultraviolet spectrum band in the infrared spectrum band, including thermal infrared. Thus, the generated target model includes more spectral information than just the visible spectrum and produces a target model that includes more than just color information and spatial information.
To provide feedback in the system 300, a spectrometer circuit 320 is included to extract spectral image information from the generated spectral content and provide the spectral image information to the control circuit 315. In certain examples, the spectrometer circuit 320 measures the intensity of light in one or more different specified wavelength bands (including spectral band s of non-visible light) and provides an indication of the intensity or intensities to the control circuit 315.
In some examples, the spectrometer circuit 320 extracts spectral image information in one or more of the near-infrared (NIR) region of light, the short wavelength infrared (SWIR) region of light, and the mid-wavelength infrared region of light (MWIR). In certain examples, the spectrometer circuit 320 extracts spectral image information in the long-wavelength infrared region (LWIR) of light. This is sometimes referred to as the thermal imaging region. The spectrometer circuit 320 provides one or more of the NIR, SWIR, MWIR, and the LWIR spectral image information to the control circuit.
Based on the extracted spectral image information, the control circuit 315 rearranges one or more micro-mirrors of the micro-mirror device to adjust the spectral content. This feedback enables the control circuit 315 to adjust the target model towards a desired target model. In some examples, the system 300 includes a memory circuit 325 integral to, or coupled to, the control circuit 315 and configured to store target spectral image information. The control circuit 315 adjusts the one or more micro-mirrors to adjust the extracted spectral image information towards the stored target spectral image information.
The control circuit 415 can include a processor to execute instructions to perform image processing on image information including spectral image information provided by the spectrometer circuit 420. The image processing by the control circuit 415 generates a pattern to position the micro-mirrors, such as a bit pattern that is written to the memory array of the micro-mirror device 405. The pattern is used to create a target image. In some examples, the control circuit 415 recurrently updates the position of one or more of the micro-mirrors to change the formed spatial image and spectral content in real time. This allows the target image to be updated to form a target model that changes in real time. In some examples, the pattern of the micro-mirror device can be updated at a rate of 8000 Hertz (Hz).
In the system 400, light from a light source (e.g. a white lamp) is focused by a lens 430 or lenses to a slit and then applied to an optical grating 435. The optical grating 435 spreads the incident tight into bands of specified wavelengths. In certain examples, a collimator is used to direct the light from the lamp. The light bands are then applied to the mirror-mirror device 405. In certain examples, the light bands are focused onto the micro-mirrors using a tens. A light band can be applied to one or more columns (or alternatively rows) of the micro-mirrors. The control circuit 415 activates specified mirrors (e.g., specified columns) of the micro-mirror device to filter the light into the separate light frequencies. This creates a light profile of light intensity versus wavelength.
In some examples, the micro-mirrors may be biased in one of two positions (e.g., +12° and −12°, or ±12° and 0°). Light of unwanted wavelengths is applied to micro-mirrors in the first position and reflected to a beam dump device 440, where photons from light of unwanted wavelengths are simply trapped. Light that is applied to micro-mirrors in the second position are used to create the desired light profile. An example is shown in
In some examples, the system 400 of
The second micro-mirror device can be coupled to the same control circuit 315, 415 or a different control circuit as the first micro-mirror device 305, 405 of
The system 600 allows fully dynamic scenes to be created using wavelengths of non-visible light. For instance, the second micro-mirror device 655 can combine thermal information from the background source with the target model information generated by the STI system 400 to generate a target scene with a warm target (e.g., a missile) in front of a cold or cool background. The system can generate target scenes having a number of targets and can reconfigure the size, shape, and spectral information of the targets and background. Target scenes may be reconfigured at a rate limited by the DMD reconfiguration rate (e.g., up to 8000 Hz).
The systems described herein allow for more accurate testing and simulation of targeting devices, such as targeting devices used in interceptor systems. Alternatively, the systems can be used to generate target scenes to defeat targeting devices. The systems may be used for any application that uses radiometric or spectral calibration, such as a satellite-deployed tracking system for example.
The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples,” All publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference(s) should be considered supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document controls.
In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc, are used merely as labels, and are not intended to impose numerical requirements on their objects.
Method examples described herein can be machine or computer-implemented at least in part. Some examples can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples. An implementation of such methods can include code, such as microcode, assembly language code, a higher-level language code, or the like. Such code can include computer readable instructions for performing various methods. The code can form portions of computer program products. Further, the code can be tangibly stored on one or more volatile or non-volatile computer-readable media during execution or at other times. These computer-readable media can include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memories (RAM's), read only memories (ROM's), and the like.
The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
