Systems, devices, and methods for protecting optics

Abstract

Provided is a system, device and method for protecting optics. The system includes an optical head (200) comprising a micro electro mechanical system (310) including an array of independently steerable micromirrors (114) in an optical path of the optical head (200) and a sensor (308) for sensing light, wherein the micro electro mechanical system (310) reflects light onto the sensor (308) for imaging.

Description

SYSTEMS, DEVICES, AND METHODS FOR PROTECTING OPTICSTechnical Field

[0001] The following relates generally to protecting optics, and more particularly to systems, devices, and methods for providing blinding protection for optics.Introduction

[0002] Ground-based lasers are being used to dazzle or damage overflying earthobservation satellites. Much like having a torch shone directly into your eyes, this creates image saturation, blooming and flaring, which degrades or completely stops the satellite from imaging the earth.

[0003] Future threats may expand this to include even higher power lasers shone from the ground maybe able to permanently damage earth observation satellites.

[0004] Future threats may expand this to include lasers mounted on spacecraft maybe able to permanently follow around an earth-observation satellite and permanently disrupt its ability to successfully image.

[0005] Accordingly, there is a need for an improved system and method for protecting optics that overcomes at least some of the disadvantages of existing systems and methods.Summary

[0006] Provided is a system for protecting optics. The system includes an optical head comprising a micro electro mechanical system (MEMS) including an array of independently steerable micromirrors in an optical path of the optical head, and a sensor for sensing light, wherein the MEMS reflects light onto the sensor for imaging.

[0007] The MEMS may include a digital micromirror device (DMD) to filter out dazzling laser light to protect the optical head.

[0008] The system may further include a satellite orbiting the earth having an imager including the optical head. The imager may take images of the earth and other objects in space.

[0009] A threat device may include laser emitter that emits the dazzling laser light towards the optical head.

[0010] The threat device may be on the earth or is mounted on a spacecraft.

[0011] The sensor may be an opto-electronic image sensor.

[0012] The system may further include a computer system configured to determine which micromirror corresponds to the dazzling laser light source.

[0013] The computer system may be configured to switch or steer the micromirrors to reflect the dazzling laser light into a beam dump.

[0014] The micromirrors may continuously reflect a percentage of the light to the sensor for the purpose of monitoring.

[0015] The micromirrors may be controlled independently to create a series of patterns that reflect excess light to the outside of the sensing area of the sensor.

[0016] The computer system may be configured to determine a general location of the dazzling laser light, estimating a location of the dazzling laser light due to a distribution of saturated pixels in the digital micromirror device, determine the location of the dazzling laser light by cycling through a sequence of on / off patterns of micromirrors of the DMD; and divert the dazzling laser light source away from the sensor by switching a corresponding micromirror within the DMD array.

[0017] The computer system may be configured to divert the dazzling laser source into a series of baffles or beam dumps designed to absorb the laser light.

[0018] The general location of the dazzling laser may be determined by predicting the laser’s location due to intelligence.

[0019] The general location of the dazzling laser may be determined by known laser installations or previous dazzling events.

[0020] Provided is a method for protecting optics. The method includes determining a general location of a dazzling laser, estimating a location of the dazzling laser due to a distribution of saturated pixels in a digital micromirror device (DMD) having micromirrors, determine the location of the dazzling laser by cycling through a sequenceof on / off patterns of micromirrors of the DMD, and diverting the dazzling laser source away from the image sensor by switching a corresponding micromirror within the DMD array.

[0021] The method may further include diverting the dazzling laser source into a series of baffles or beam dumps designed to absorb the laser light.

[0022] The method may further include cycling through a sequence of on / off patterns of micromirrors until an optical power meter determines that the image is no longer dazzled.

[0023] The method may further include re-assessing intensity of the dazzling laser and position of the dazzling laser.

[0024] Other aspects and features will become apparent to those ordinarily skilled in the art, upon review of the following description of some exemplary embodiments.Brief Description of the Drawings

[0025] The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the present specification. In the drawings:

[0026] Figure 1 is a block diagram of a system for protecting optics, in accordance with an embodiment;

[0027] Figures 2A and 2B are perspective and detailed views, respectively, of a digital micromirror device, in accordance with an embodiment;

[0028] Figure 3 is a diagram of a conventional optical head;

[0029] Figure 4 is a diagram of a optical head device for protecting optics, in accordance with an embodiment; and

[0030] Figure 5 is a flow chart of a method for protecting optics, in accordance with an embodiment.Detailed Description

[0031] Various apparatuses or processes will be described below to provide an example of each claimed embodiment. No embodiment described below limits anyclaimed embodiment and any claimed embodiment may cover processes or apparatuses that differ from those described below. The claimed embodiments are not limited to apparatuses or processes having all of the features of any one apparatus or process described below or to features common to multiple or all of the apparatuses described below.

[0032] One or more systems described herein may be implemented in computer programs executing field programmable gate arrays (FPGA), microcontroller, edge compute platform or spacecraft on-board computers. The computer may include at least one processor, a data storage system (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device.

[0033] Each program is preferably implemented in a high level procedural or object oriented programming and / or scripting language to communicate with a computer system. In any case, the language may be a compiled or interpreted language. Each such computer program is preferably stored on a storage media or a device readable by a general or special purpose programmable computer for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein.

[0034] A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary a variety of optional components are described to illustrate the wide variety of possible embodiments of the present invention.

[0035] Further, although process steps, method steps, algorithms or the like may be described (in the disclosure and I or in the claims) in a sequential order, such processes, methods and algorithms may be configured to work in alternate orders. In other words, any sequence or order of steps that may be described does not necessarily indicate a requirement that the steps be performed in that order. The steps of processes described herein may be performed in any order that is practical. Further, some steps may be performed simultaneously.

[0036] When a single device or article is described herein, it will be readily apparent that more than one device / article (whether or not they cooperate) may be used in placeof a single device I article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it will be readily apparent that a single device I article may be used in place of the more than one device or article.

[0037] Figure 1 illustrates a system 100 for protecting optics, in accordance with an embodiment. The system 100 includes a satellite 102 orbiting the earth 104, or another celestial body. The satellite 102 may be an earth observation satellite that includes an imager 106 having an optical system or optics. The imager 106 takes images along an optical path 101 of the earth 106 and other objects in space.

[0038] The system 100 includes a threat device 108 that includes a laser 110 that emits dazzling light. The laser 110 emits laser light into the imager 106 to attempt to blind or disable the imager 106. The threat device 108 may be on the earth 104. The threat device 108 may be mounted on a spacecraft 112. The threat device 108 may be controlled by actors intent on degrading or damaging the performance of the imager 106.

[0039] The system 100 includes a digital micromirror device (DMD) 114 to filter out such laser 110 dazzling sources to protect the imager 106. The DMD 114 may enable continuous imaging by the imager 106.

[0040] Figures 2A and 2B illustrate a digital micromirror Device (DMD) 150, in accordance with an embodiment. The DMD 150 may be the DMD 114 of Figure 1. The DMD includes an array 152 of micromirrors 154. Each micromirror or pixel 154 is configured to pivot independently from the other micromirrors 154 in the array 152.

[0041] Referring again to Figure 1 , the system 100 includes a computer system 116 configured to determine which micromirror 154 corresponds to the dazzling light source 110. The computer system 116 is configured to switch or steer the micromirror 154 to reflect the laser light 110 into a beam dump so as to minimize specular reflections. The computer system 116 may be located on the satellite 102 or at another location in computational communication with the satellite 102.

[0042] The system 100 may be applicable to all opto-electronics used for observation or detection. The system 100 may be applicable for visible light cameras. The system 100 may be applicable to infra red and avalanche photo diodes used for laserranging systems. Conventional techniques may have only been used to reflect light onto sensors for spectroscopy purposes but not for imaging.

[0043] The system 100 may address risk of damaging high sensitivity optoelectronics 106 due to reduced control over spacecraft during detumbling.

[0044] The system 100 may be applied in space, aerial, and terrestrial optics considered critical or defense-sensitive.

[0045] The DMD arrays 152 may naturally act as blaze diffraction gratings. The blaze diffraction grating deflects coherent light (such as laser light) off into a set of different ‘blaze’ angles; whilst incoherent light is reflected normally. This blaze effect may be used to deflect dazzling laser light sources harmlessly away.

[0046] The system 100 may advantageously be largely wavelength independent, so can be used to filter out a wide range of laser dazzling sources. Whereas a blaze diffraction technique may only work for particular wavelengths.

[0047] The system 100 may advantageously use fewer optical elements, which may result in less optical power loss.

[0048] Referring to Figure 3, illustrated therein is a conventional optical head device 200 that does not protect optics, in accordance with an embodiment. A light source 202 passes through a lens 204 to create focused light 206 which passes on to a sensor 208. In conventional photograph systems the incoming light 202 may be controlled by a shutter or baffle assembly. Conventional systems 200 may use special selective coatings on optics as well as hope to avoid excessive expose to direct sunlight. Conventional systems 200 may neglect military aspects.

[0049] Referring to Figure 4, illustrated therein is an optical head device 300 for protecting optics, in accordance with an embodiment. The device 300 includes a lens 304 that focuses received light 302 to create focuses light 306.

[0050] The device 300 includes a micro electro mechanical system (MEMS) 310. The MEMS 310 includes an array of micromirrors (e.g., Digital Mirror Device (DMD) 150, having micromirrors 154 of Figure 2A) in the optical path of the optical head 300.

[0051] The focused light 306 is focused on a MEMS mirror array 310, or DMD. The MEMS mirror array 310 reflects the light 312 onto a sensor 308. The MEMS 310 reflects light onto the sensor 308 for imaging.

[0052] The light 306 is focused onto the DMD array 310, and then may be refocused onto the sensor 308. There may be another lens between the DMD array 310 and the sensor 308 in order to perform refocusing.

[0053] The steerable MEMS mirror array 310 is situated between the optoelectronic sensor 308 and the first optics 304 of the optical head 300.

[0054] When not in use, the mirrors 310 reflect the light away from the sensor 308 to protect the sensor 308 from strong light 302 that could cause damage or excessive inertia of the sensor 308 due to saturation. The saturation may be due to the device 300 facing directly or indirectly into the Sun. The saturation may be due to malicious activities, such as dazzling observational satellites from the ground (e.g., 108) or in orbit (e.g., 112).

[0055] The mirror 310 may be set to continuously reflect a percentage of the light 312 to the sensor 308 for the purpose of monitoring. The mirror 310 may switch to full, none, or any other mode for the actual operation of the optical head 300.

[0056] The optical device 300 may be protected from blinding via use of fast acting reduction of the exposure to the optical input (i.e. light). The optical device may offer fast reaction and avoid reduction of the field of view of the sensor 308.

[0057] Each micromirror (e.g., 154) can be controlled independently. The device 300 creates a series of patterns that reflects excess light to the outside of the sensing area of the sensor 308. These patterns utilize a variety of locations of the micro mirrors (154), so to cover discretely all the image area, or selected sections.

[0058] Turing to Figure 5, illustrated therein is a method 400 for protecting optics, in accordance with an embodiment. The method 500 may be performed by the computer system 116 of Figure 1.

[0059] At 402, a general location of a dazzling laser is determined. The general location of the dazzling laser may be determined by predicting the laser’s location due tointelligence. The general location of the dazzling laser may be determined by known laser installations or previous dazzling events.

[0060] At 404, the location of the laser is estimated due to the distribution of the saturated pixels in the DMD, blooms or flares. The system determines the presence of high intensity light being emitted from an object to indicate dazzling. The position of the object with respect to the protection system is determined. An estimated location of the source of the disruption is determined from the observed line of sight of the object.

[0061] The method may include re-assessment of the conditions (intensity of the light and position of the object). The re-assessment of the conditions may advantageously allow the protective system to be fast acting and allow for periodic resumption of normal reflection.

[0062] The high light intensity detected on the whole sensing area of the sensor would be the indication of direct exposure to intensive light. Partial high intensity exposure may also be used to estimate the location of the disrupting source.

[0063] At 406, the location of the laser is determined by cycling through a sequence of on / off patterns of micromirrors of the DMD.

[0064] The method may include cycling through a sequence of on / off patterns of micromirrors until the image is no longer dazzled.

[0065] The method may include cycling through a sequence of on / off patterns of micromirrors until a separate optical power meter determines that the image is no longer dazzled. This has the advantage of being able to react faster and search the space quicker, than can be performed using the camera and image processing.

[0066] The method may blend together two independent parameters the location of the dazzling laser and the location of the sensor pixels that are exposed to the elevated light input. The location of the dazzling laser is a position in three-dimensional space.

[0067] The method includes various modes of operation by applying various patterns of reflection to the DMD.

[0068] For example, the method may include evenly spaced (e.g., 30%) of the DMD reflecting the light to the sensor, preventing all the sensing pixels from saturationfrom dazzling, while still operating and gathering images. The method may cycle through all mirrors, so the full sensor’s exposure is even over time. The method may reduce the risk of getting dead pixels.

[0069] In case of observing Earth at night, the method may include DMD patterns that are adaptive to the received image. The method may include determining the areas with low light input that need high amplifications of the detected signal. By blocking the light from brighter places of the image, the method may safely maximize the amplification.

[0070] There may be a plurality of usual patterns that are applied in various scenarios. Having such a capability is the enabler for further applications.

[0071] At 408, the dazzling laser source is diverted away from the image sensor. The dazzling laser source may be diverted into a series of baffles or beam dumps designed to absorb the laser light safely (and without creating further stray-light effects). The diversion happens by switching the corresponding micromirror within the DMD array.

[0072] While the above description provides examples of one or more apparatus, methods, or systems, it will be appreciated that other apparatus, methods, or systems may be within the scope of the claims as interpreted by one of skill in the art.

Claims

Claims:1 . A system for protecting optics, the system comprising: an optical head comprising: a micro electro mechanical system (MEMS) including an array of independently steerable micromirrors in an optical path of the optical head; and a sensor for sensing light, wherein the MEMS reflects light onto the sensor for imaging.

2. The system of claim 1 , wherein the MEMS includes a digital micromirror device (DMD) to filter out dazzling laser light to protect the optical head.

3. The system of claim 1 further comprising: a satellite orbiting the earth having an imager including the optical head, wherein the imager takes images of the earth and other objects in space.

4. The system of claim 2, wherein a threat device includes a laser emitter that emits the dazzling laser light towards the optical head.

5. The system of claim 4, wherein the threat device is on the earth or is mounted on a spacecraft.

6. The system of claim 1 , wherein the sensor is an opto-electronic image sensor.

7. The system of claim 2 further comprising: a computer system configured to determine which micromirror corresponds to the dazzling laser light source.

8. The system of claim 7, wherein the computer system is configured to switch or steer the micromirrors to reflect the dazzling laser light into a beam dump.

9. The system of claim 1 , wherein the micromirrors continuously reflect a percentage of the light to the sensor for the purpose of monitoring.

10. The system of claim 1 , wherein each micromirror is controlled independently to create a series of patterns that reflects excess light to the outside of the sensing area of the sensor.11 . The system of claim 7, wherein the computer system is configured to: determine a general location of the dazzling laser light; estimate a location of the dazzling laser light due to a distribution of saturated pixels in the digital micromirror device; determine the location of the dazzling laser light by cycling through a sequence of on / off patterns of micromirrors of the DMD; and divert the dazzling laser light source away from the sensor by switching a corresponding micromirror within the DMD array.

12. The system of claim 11 , wherein the computer system is further configured to divert the dazzling laser source into a series of baffles or beam dumps designed to absorb the laser light.

13. The system of claim 11 , wherein the general location of the dazzling laser is determined by predicting the laser’s location due to intelligence.

14. The system of claim 11 , wherein the general location of the dazzling laser is determined by known laser installations or previous dazzling events.

15. A method for protecting optics, the method comprising: determining a general location of a dazzling laser; estimating a location of the dazzling laser due to a distribution of saturated pixels in a digital micromirror device (DMD) having micromirrors; determine the location of the dazzling laser by cycling through a sequence of on / off patterns of micromirrors of the DMD; and diverting the dazzling laser source away from the image sensor by switching a corresponding micromirror within the DMD array.

16. The method of claim 15 further comprising: diverting the dazzling laser source into a series of baffles or beam dumps designed to absorb the laser light.

17. The method of claim 15, wherein the general location of the dazzling laser is determined by predicting the laser’s location due to intelligence.

18. The method of claim 15, wherein the general location of the dazzling laser is determined by known laser installations or previous dazzling events.

19. The method of claim 15 further comprising: cycling through a sequence of on / off patterns of micromirrors until an optical power meter determines that the image is no longer dazzled.

20. The method of claim 15 further comprising: re-assessing intensity of the dazzling laser and position of the dazzling laser.

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