Gapless detector mosaic imaging systems and methods

Imaging systems and methods that enable multiple detectors to be used to capture multiple component images that can be fused to create a composite image of a scene, without introducing gaps in that composite image in areas corresponding to the boundaries of the detectors, are provided. The system includes imaging optics, such as a telescope, that at least in part define an optical path extending between an exit pupil and a focal plane. Field segmentation optics are located within the optical path, to create multiple, partially overlapping component images. At least one detector is provided to produce an image signal representing each of the component images. A composite image is then formed by registering and fusing the component images.

FIELD

Systems and methods for forming images using multiple detector arrays are provided. More particular, systems and methods for forming images using multiple detector arrays, without suffering the effects of gaps introduced in areas between adjacent detector arrays, are provided.

BACKGROUND

In the broad field of optical imaging, light emanating from objects of interest is projected onto a focal plane by imaging optics. The light may be ordinary visible light, infrared, or other, such as ultraviolet or even radio waves. The imaging optics may consist of lenses, mirrors, or other combinations, including diffractive optics. In most situations, a detector array serves as the light-sensing element in the imaging system. This detector array typically consists of a light-sensing material, usually a semiconductor, which is divided into a number of picture elements, or pixels, each of which senses the light falling locally on a small area. Imaging systems can also utilize photographic film or any other ‘staring’ type detector array.

The total number of pixels available in any single detector array is often a limiting factor in the design of an imaging system that provides the desired amount of image information or resolution. Also, in telescope applications, the physical size of the detector array, and in particular the area of the detector array, can also be a limiting factor. In particular, a single detector having a desired minimum physical area and resolution may not be available, or may be cost prohibitive. A common solution is to place a number of detector arrays at the focal plane of the optics, forming a “mosaic” detector in which the individual detector arrays together provide multiple times more pixels than can be achieved with any single detector array. But mosaics come at the cost of gaps between the individual detector arrays or array modules, since there must be space surrounding the detector elements for readout circuitry, electrical interfaces, and mechanical support features. Even the most sophisticated detector packaging schemes are unable to provide a continuous array of pixels without gaps between detector modules.

Accordingly, it would be desirable to enable the use of multiple detector arrays, without a loss of image information in areas between adjacent detector arrays.

SUMMARY

The present disclosure provides imaging systems and methods that enable the collection of image information using multiple detector arrays, without the loss of information from areas at or corresponding to the boundaries between adjacent detector arrays. An imaging system in accordance with embodiments of the present disclosure includes imaging optics, field segmentation optics, and multiple detector arrays. The field segmentation optics are located between the imaging optics and the focal plane of the imaging optics, and form multiple component images or image segments corresponding to different sub-areas within a field of view of the imaging optics. Each component image is directed to one of the detector arrays. In accordance with embodiments of the present disclosure, each component image formed by the field segmentation optics encompasses a sub-area of a scene that at least partially overlaps an adjacent or neighboring sub-area of the scene encompassed by another one of the component images. Accordingly, systems in accordance with embodiments of the present disclosure collect multiple overlapping component images. A composite image is formed by registering and fusing the multiple overlapping image segments. In accordance with embodiments of the present disclosure, the composite image can be formed without a loss of image information in areas of overlap as compared to non-overlapping areas of the composite images.

In embodiments of the present disclosure, the “mosaic gap” problem is solved by placing field segmentation optics within an optical path of the imaging system. The field segmentation optics can be located nearer to the focal plane of the imaging optics than to the exit pupil of the imaging optics, and can be in the form of one or more mirrors. Alternatively or in addition, the field segmentation optics can be in the form of a multi-faceted prism. Each detector is located at a component focal plane on which a corresponding component image is focused. Accordingly, the detectors can be located on different physical planes.

Methods in accordance with embodiments of the present disclosure include collecting light from a scene using imaging optics that focus the collected light to form image information. The light collected by the imaging optics is divided into multiple overlapping component images by positioning field segmentation optics between the exit pupil and the focal plane of the imaging optics. Moreover, each component image is focused onto a component focal plane. The image information within each image component is detected by a detector located at each of the component focal planes. The image information thus collected is then registered and fused to create a composite image.

Additional features and advantages of embodiments of the present disclosure will become more readily apparent from the following description, particularly when considered together with the accompanying drawings.

DETAILED DESCRIPTION

FIG.1depicts an imaging scenario incorporating an imaging system104in accordance with an exemplary embodiment of the present disclosure. In this example, the imaging system104is carried on a platform108. Although the platform108is shown as a satellite, embodiments of the present disclosure are not so limited, for example, the imaging system104can be associated with a platform108in the form of any sort of vehicle or stationary structure, such as an airplane, balloon, spacecraft, truck, car, ship, tower, tripod, etc. In accordance with still other embodiments, the imaging system104need not be associated with a platform. For instance, the imaging system104can be hand held. In general, the imaging system104has a field of view112from within which light reflected or originating from an area116of a scene120can be collected to form an image. In accordance with embodiments of the present disclosure, the light can be of various wavelengths, such as but not limited to visible light, infrared light, and ultraviolet light.

An imaging system104in accordance with embodiments of the present disclosure divides an area116of the scene120in the field of view112of the system104into multiple different sub-areas124. Each sub-area124at least partially overlaps a neighboring or adjacent sub-area124within an overlap region or area128. As discussed in greater detail elsewhere herein, the imaging system104includes multiple detectors, with a different detector assigned to creating an image, hereinafter referred to as a sub-image or component image, of each sub-area124. Because each sub-area124overlaps each neighboring sub-area124, and thus each component image encompassing a sub-area124partially overlaps a component image encompassing a neighboring sub-area124, a composite image of the entire area116within the field of view112of the system104can be formed, while avoiding the undesirable effects typically encountered by systems incorporating multiple detectors to collect images of a scene within a common integration period.

FIGS.2A and2Bdepict components of an imaging system104in accordance with embodiments of the present disclosure. The imaging system104generally includes imaging optics204, field segmentation optics208, and a plurality of detectors212. In addition, as can be appreciated by one of skill in the art after consideration of the present disclosure, an imaging system104in accordance with embodiments of the present disclosure can include a shutter, aperture, control system, power supply, support structure, and other ancillary components typical of an electronic or digital imaging system.

The imaging optics204collect light from within the field of view112of the imaging system104, and focus the collected light onto a focal plane216. As an example, but without limitation, the imaging optics204can be configured as a telescope. Moreover, the imaging optics204can include refractive, reflective, or combinations of refractive and reflective elements.

The field segmentation optics208are located in an optical path220defined at least in part by the imaging optics204. More particularly, the field segmentation optics208are located between the exit pupil224of the imaging optics204, and the focal plane216. In accordance with embodiments of the present disclosure, the field segmentation optics208are located closer to the focal plane216than to the exit pupil224. The field segmentation optics208divide the light collected by the imaging optics204, and in particular define multiple sub-images232corresponding to the multiple sub-areas124included in the area116within the field of view112of the system104. Moreover, neighboring sub-images232defined by the field segmentation optics208encompass sub-areas124that overlap one another in an overlap area or areas128. The field segmentation optics208in the example configuration illustrated inFIGS.2A and2Binclude two facets228that divide the light passed along the optical path220of the imaging system104into two component or sub-images232. Accordingly, the focal plane216in this example is a split focal plane that includes a first component focal plane216aand a second component focal plane216b.More particularly, a first one of the facets228adirects a first one of the component images232aonto the first component focal plane216aand a second one of the facets228bdirects a second one of the component images232bonto the second component focal plane216b.Each of the component focal planes216aand216bare the same focal distance from the imaging optics204. As shown, the facets228can be in the form of reflective or mirrored planar surfaces. In accordance with other embodiments of the present disclosure, the facets228can be in the form of prisms or prism facets.

In accordance with embodiments of the present disclosure, one detector212is provided for each component image232formed by the field segmentation optics208. Accordingly, in the example imaging system104ofFIGS.2A and2B, the plurality of detectors212includes first212aand second212bdetectors. As an example, but without limitation, the detectors212can include detector arrays or image sensors214having two-dimensional arrays of photosensitive sites or pixels that generate an electric charge in response to exposure to light. Accordingly, the detectors212can include detector arrays214in the form of charge coupled devices (CCD), complementary metal oxide semiconductor (CMOS) devices, organic photodetectors, or other solid-state imaging devices. In accordance with still other embodiments of the present disclosure, the detectors212can include sheets or rolls of photographic film. The detectors212are located such that light sensitive surfaces of the detectors212are coincident with the component focal planes216aand216bdefined by the imaging optics204and the field segmentation optics208.

As can be appreciated by one of skill in the art after consideration of the present disclosure, the placement of the field segmentation optics208between the exit pupil224and the focal plane216creates component images or sub-images232that partially overlap one another. As illustrated inFIG.3, light included in a sub-image or a component image232collected from a sub-area124includes at least one overlapping light portion304and a non-overlapping light portion308. The light in the overlapping light portion or portions304is light collected from the overlapping area or areas128of the sub-area124, while the light in the non-overlapping light portion308is light collected from the non-overlapping portion of the sub-area124. In a two detector212imaging system104in accordance with embodiments of the present disclosure, the overlapping portion of light304aincluded in the first component image232aand the overlapping portion of light304bincluded in the second component image232bare collected from the same area128within the field of view112of the imaging system104. The nonoverlapping portions of light308are unique to the respective component images232. That is, the non-overlapping portion of light308ain the first component image232aincludes light collected from a different portion of the scene120than the nonoverlapping portion of light308bin the second component image232b.For example, and with reference again toFIG.1, the first sub-image232aformed on a surface of the first detector212aincludes image information from the first sub-area124a,while the second sub-image232bformed on a surface of the second detector212bincludes image information from the second sub-area124b.Moreover, the first sub-image232aincludes image information304afrom the overlapping area128, in addition to image information308acollected from a non-overlapping portion of the area124a,while the second sub-image232bincludes image information304bfrom the overlapping area128, in addition to image information308bcollected from a non-overlapping portion of the area124b.

FIG.4is a graph illustrating the relative illumination of the detectors212in an example two-detector imaging system104in accordance with embodiments of the present disclosure. The first plot404depicts the relative intensity of light at different field angles within a selected plane within the field of view112of the imaging system104received at the first detector212a,while the second plot408depicts the relative intensity of light at different field angles within the selected plane within the field of view112of the imaging system104received at the second detector212b.In this example, the light included in the first nonoverlapping portion308ais collected from a first sub-area124awithin a field angle of about −5° to about −1°, and has a relative intensity at the first detector212aof 1. No light within the first nonoverlapping portion308ais delivered to the second detector212b,thus the corresponding intensity of the light received at the second detector212bat the field angles encompassing the first sub-area124ais zero. The light included in the overlapping portions304aand304bis collected from the overlap area128, which in this example is within a field angle of about −1° to about 1°. As the field angle increases from about −1° to about 1°, the intensity of the light received at the first detector212adecreases from 1 to 0, while the intensity of the light received at the second detector212bincreases from 0 to 1. The light included in the second nonoverlapping portion308bis collected from a sub area within a field angle of about 1° to about 5°, and has a relative intensity at the first detector212bof 1. No light within the second nonoverlapping portion308bis delivered to the first detector212a,thus the corresponding intensity of the light received at the first detector212aat the field angles encompassing the second sub-area124bis zero. As demonstrated by the example relative illumination values, by adding the image information or signals collected from the overlapping portions304aand304b,the resulting relative illumination is constant or about constant (e.g. within +/−5%) across the entire field of view112.

Imaging systems104in accordance with embodiments of the present disclosure can form different numbers of sub-images232, and can include a corresponding number of detectors212. For example,FIGS.5A and5Bdepict a four detector212imaging system104in accordance with embodiments of the present disclosure. In this example, the field segmentation optics208, depicted inFIG.6, can include a faceted mirror having four mirror segments228a-dlocated along the optical path220of the imaging system104, with each mirror segment228a-ddirecting light collected from within a different sub-area124to a corresponding detector212a-d.In this example, each of the component focal planes214corresponding to the locations of the light sensitive surfaces or planes of the detectors212are in different planes.

FIG.7depicts component images232collected by a four detector212imaging system104in accordance with embodiments of the present disclosure. More particularly, the component images232a-d,as imaged onto corresponding detectors212a-dhaving light sensitive surfaces located at the respective component focal planes216a-d,are depicted. In this example, the light included in each of the component images232a-dincludes a first overlapping light portion704shared with a horizontally adjacent component image232, and a second overlapping light portion708shared with a vertically adjacent component image. In addition, a third overlapping light portion712that includes both a portion of the first704overlapping light portion704and the second overlapping light portion708is included in each of the component images232a-d.Portions of component images232not included in any overlapping portion704,708, or712are part of non-overlapping light portions308, each of which is unique to the component image232in which it is included.

FIG.8depicts a composite image804formed from the component images232a-dreceived at the detectors212in the example ofFIG.7. More particularly, the composite image804is a result of combining or fusing image information from the different component images232collected at the different imaging system104detectors212a-d.In general, fusing the image information includes registering the overlapping component images232a-d(i.e., the component images232a-dencompassing overlapping sub-areas124of the imaged area116), and adding the intensity information within the component images232a-dencompassing the overlap region or regions128. In accordance with embodiments of the present disclosure, the portions of the composite image804corresponding to the various overlapping light portions704,708, and712formed from combining signals from two or more detectors212are indistinguishable from the portions of the composite image804formed from signals supplied by only one of the detectors212.

FIGS.9A and9Bdepict a sixteen component image imaging system104in accordance with embodiments of the present disclosure. As depicted in this example, the field segmentation optics208can include a multi-faceted mirror, with sixteen facets228intersecting a portion of the light collected by the imaging optics204and passed along the optical path220. Moreover, the facets228at which collected light is received can be disposed in a roughly semicircular configuration. In this example, sixteen detectors212are disposed to receive the sixteen component images232formed by the facets228, in a 1:1 relationship. An active surface of each detector212is at the same focal distance from the imaging optics204. Due to the placement of the field segmentation optics208within the optical path220, and closer to the focal plane216than to the exit pupil224, each component image formed at each detector212encompasses a sub-area of the scene that partially overlaps the sub-area included in the component image formed at neighboring detectors212. Accordingly, a composite image that does not vary in image quality across the image can be formed by fusing the component images.

FIGS.10A and10Bdepict imaging systems in accordance with embodiments of the present disclosure having prisms as field segmentation optics208. In general, the prisms1004are located along the optical path220, and are closer to the focal plane216than to the exit pupil224. Moreover, the prisms1004divide the light in the optical path220into multiple, partially overlapping fields. As shown inFIG.10B, a second set of prisms1008can be included. The second set of prisms1008have a wedge angle opposite the first set of prisms1004, to redirect the field segments back to focus on a common focal plane. This configuration separates component images, while allowing the component focal planes214, and thus the different detectors212, to be located on a common physical plane. As can be appreciated by one of skill in the art after consideration of the present disclosure, while the detectors212are physically separated from one another, they receive component images232consisting of light collected from sub-areas124of the area116within the field of view112of the system104that partially overlap adjacent sub-areas124. In accordance with at least some embodiments of the present disclosure, each prism1004,1008can be replaced by an achromatic prism pair, which can partially correct for chromatic aberrations. Aberrations can also be reduced by introducing cylindrical or spherical surfaces on the prisms.

FIGS.11A,11B,11C and11Ddepict the imaging surfaces of detectors212, and in particular depict overlap regions704,708, and712and non-overlap regions308of a composite image804in multiple component image imaging systems104in accordance with embodiments of the present disclosure. The number of overlap regions in different schemes involving imaging systems104having 2, 4, 9, and 16 detectors212respectively are illustrated. Each array segment is labeled with the number of edges that are shared with neighbor arrays: 1, 2, 3, or 4. Note that overlap regions712that encompass light included in more than two component images232only occur in imaging systems104having more than two detectors212.

FIG.12is a graph depicting relationships between a required amount of pixel overlap versus number of component images232at different optical system speeds in accordance with embodiments of the present disclosure. In particular, the required fraction of each detector212dedicated to overlap regions204or208is plotted, under some simplifying assumptions as to the position of the field segmentation optics208, to ensure a constant or near-constant resolution and relative illumination across the entire composite image. For example, a near constant illumination can be an illumination that varies by less than 5% across the system field of view112. The graph gives an indication of the amount of overlap “overhead” incurred in choosing to spread the field of view112of the imaging system104across a certain number of detector arrays212. The amount of detector212area that needs to be dedicated to the overlap regions increases with number of detectors212and with the optical ‘speed’, or lower f-number, of the imaging system104. In general, the overlap is increased as the field segmentation optics are moved closer to the exit pupil224of the imaging optics204. Note that the case that uses nine detector arrays212(as inFIG.11C) involves a single detector212array at the center of the field. In this situation, the field segmentation optics208may consist of a square aperture surrounded by eight mirror facets. Light heading toward the central detector212would pass through the aperture without reflection, while the other field segments would reflect off of mirror facets onto their respective detectors.

FIGS.13A and13Bdepict a three component image232a-cimaging system104in accordance with embodiments of the present disclosure. More particularly, a configuration that combines three detectors212in a single row, using field segmentation optics208that include a central aperture region and two mirrors228. Accordingly, for the central detector212cthere is no mirror between the exit pupil224and the detector212. The mirrors228aand228bon either side of the central detector212cdefine the field segments, reflecting light headed to those segments onto the top212aand bottom212bdetectors. The cross-fade effect that happens at the border between the component images232aand232bdirected by the mirrors228to the detectors212aand212band the component image232cthat is not reflected by the mirrors228(depicted inFIG.13B) is the same as or similar to the cross fade between adjacent component images232defined by mirrors having intersecting edges.

Variations on this approach include as few as two detectors and a single mirror, to any number of alternating pairs of reflected-transmitted field segments. The same reflection-transmission concept applies to two-dimensional arrays of detectors as well. For example, in a nine-detector configuration central field segment is an open segment, with the eight surrounding segments defined by mirror facets. The number of possible detectors that can be arrayed in this fashion is unlimited in principle.

FIGS.14A,14B,14C, and14Ddepict a multiple component image imaging system104in accordance with further embodiments of the present disclosure. In particular, a configuration optimized for scanning-type imaging systems104is illustrated. Scanning systems are commonly used when high resolution is needed. The detectors212in such embodiments can consist of linear arrays of detection elements, or wide-aspect-ratio arrays with a limited number of rows in the along-track direction and many pixels in the cross-track direction. Typically, a number of detectors212are laid out at the focal plane in a staggered arrangement with some overlap in coverage in the cross-track direction. In this example, the array layout is similarly staggered, but two of the arrays are mounted on a secondary focal plane, with mirrors228aand228bdirecting a portion of the field to the secondary plane.FIG.14Dshows how the virtual component images232aand232bof the detectors208aand208bon the secondary plane line up with the component images232c-eof the detectors208c-eon the primary plane to form a continuous linear array, with overlapping seams. The advantage of this arrangement is that the along-track field of view (FOV) of the optics can be reduced significantly. This FOV can often be the limiting factor in the design of scanning optics. Accordingly, higher performing, lower size, weight, and power (SWAP) systems are enabled. Another advantage is that all detector modules are imaged simultaneously, whereas in the traditional staggered array there is a small difference in time and view angle between the rows of detector modules. Variations on the linear approach include expanding to any number of modules in the cross-track direction. The mirrors do not need to be at 45 degrees as shown, but can be at any convenient angle.

FIGS.15A,15B and15Cdepict design considerations for a multiple component image imaging system104in accordance with embodiments of the present disclosure.FIG.15Ashows a single detector module212of outer dimension D. The inner region of size P marks the pitch at which detector elements or pixels are arrayed. There is an overlap region of size O/2 on either side of the inner region boundary (D=P+O). InFIG.15B, four detectors are arrayed in overlapping fashion, on replication pitch P. The overlap region extends ±O/2 on either side of the boundary. This overlapping configuration represents the effective combination of the reflections of four detectors from four mirror facets. The facet tilt is in a direction away from the central axis, along a plane defined by the central axis and the center of the detector module. The edge of each mirror facet is delineated by the intersection of the mirror plane with the guide rays as shown. The rays that define the mirror corners are chief rays from the center of the exit pupil to the corners of the inner region P. For mirror corners not on a boundary, where the detector area can be used, the rays that define the outer boundaries are from the edge of the pupil to the edge of the full detector D.FIG.15Ashows the four physical detectors, located so that their virtual images form the desired continuous, overlapping focal plane. The example shown with four mirrors and four detectors, can be expanded to any N×M array of detector modules, which may be of uniform or differing sizes.

In accordance with further embodiments of the present disclosure, the imaging system104can be configured with a curved focal plane. Optical designs can be significantly more compact if a curved focal plane is allowed. Fabrication of detector modules with curved surface figures are possible, although costly. It is an advantage to be able to use a mosaic of relatively small detector modules with curved surfaces covering a portion of the field, rather than one large curved module. Without the use of curved detector modules, a mosaic of flat modules that piecewise approximate a curved focal plane, each spanning a limited field segment, can fall within acceptable focus limits.

FIG.16is a block diagram of an imaging system104in accordance with embodiments of the present disclosure. The imaging system104generally includes imaging optics204, field segmentation optics208, a plurality of detectors212, imaging or focal plane electronics1604, and host system electronics1608. As also discussed elsewhere herein, the imaging optics204operate to collect light from within a field of view112of the imaging system104, and focuses that light onto a focal plane. The imaging optics204can, for example, comprise a telescope. In accordance with at least some embodiments of the present disclosure, the imaging optics204can include various additional optical elements, including but not limited to filters, shutters, and apertures. Moreover, the imaging optics204can have a fixed or variable focal length.

The field segmentation optics208are located between the exit pupil224of the imaging optics204and the focal plane, and can include one or more mirrors, one or more multifaceted prisms, or combinations of mirrors or prisms and open apertures or paths. The field segmentation optics204operate to divide the collected image information into multiple sub-images or component images, and further establish a set of component focal planes, with each sub-image focused on a different one of the component focal planes. Each of component image partially overlaps at least one other component image.

The plurality of detectors212include at least one detector212for each of the component images, and are located at the component focal planes. The detectors212can include a digital focal plane array or detector array214. Accordingly, the detectors212can include detector arrays incorporating a plurality of pixels disposed in one or more rows and columns. As an example, but without limitation, each detector212in the plurality of detectors212can include a backside illuminated CMOS image sensor having a 1024×1024 two-dimensional array of pixels. As can be appreciated by one of skill in the art after consideration of the present disclosure, in addition to a focal plane array formed from a plurality of photosensitive sites or pixels, the detectors212can incorporate or be associated with driver and analog-to-digital conversion (ADC) circuitry, enabling the detectors212to provide a digital output representative of an amplitude or intensity of light detected at each pixel within the detector array. In accordance with other embodiments of the present disclosure, the detectors212can be implemented as photographic films.

Each of the detectors212is operatively connected to the imaging electronics1604. The imaging electronics1604generally include memory1612, data storage1616, and one or more processors1620. The imaging electronics memory1612can include volatile or non-volatile solid-state memory, such as DRAM, SDRAM, or the like. The memory1612can provide short or long term storage for application or operating instructions1624that are executed by the processor1620to implement imaging operations or functions of the imaging system104. The memory1612can also store image data, interim image data, configurable parameters, operating system instructions, intermediate data products, output data, and the like. In accordance with further embodiments of the present disclosure, the application instructions1624can include instructions for operating the detectors212, performing image data fusion operations, and the like. The imaging electronics data storage1616generally includes non-volatile data storage, such as flash memory, solid-state drives, hard disk drives, optical disk drives, erasable programmable ROM, and the like. The data storage1616can provide short or long term storage for application instructions that are executed by the imaging electronics processor1620, configurable parameters, intermediate data products, output data, and the like. The processor1620can include one or more multi-threaded processors, graphics processing units (GPUs), general purpose processors, field-programmable gate arrays, or the like. For example, the processor1620can be formed from a multi-threaded processor in combination with multiple GPUs. In accordance with further embodiments of the present disclosure, the processor1620can include a plurality of boards or cards, with each board including memory and a GPU or other processor.

Accordingly, the imaging electronics1604can provide control signals for operation of the detectors212. As can be appreciated by one of skill in the art after consideration of the present disclosure, examples of control signals provided to the detectors212include signals enabling the conversion of incident light into electronic charge at some or all of the pixels, signals controlling integration times, signals controlling amplification levels, and the like. The operations performed by the imaging electronics1604can also include initiating and handling readout operations, including the temporary or long-term storage of component image information. The imaging electronics1604can additionally perform image fusing operations, in which component image information collected by the multiple detectors212is fused to create a composite image. Moreover, the composite image formed from the fusion of multiple component images is free from the effects of gaps present in typical systems incorporating multiple detectors to obtain image information.

The host system1608can include a processor1628, memory1632, data storage1636, and a communications interface1640. The processor1628can include a general purpose programmable processor or the like. The memory1632can include, for example, volatile or non-volatile memory, and can provide short or long-term storage for application programming or instructions, control parameters, intermediate data products, data, or the like. The memory1632can provide short or long term storage for application or operating instructions1644that are executed by the processor1628to implement imaging operations or functions of the imaging system104. The memory1632can also store image data, interim image data, configurable parameters, operating instructions, intermediate data products, output data, and the like. In accordance with further embodiments of the present disclosure, the application instructions1644can include instructions for operating the detectors212, performing image data fusion operations, operations associated with the operation of the platform108, and the like. The data storage1636generally includes non-volatile storage for application programming or instructions, control parameters, intermediate data products, data, or the like. In addition to supporting the passing of commands to and the receiving of data from the imaging electronics1604, the communications interface1640can support communications between the imaging system104and remote systems or communication nodes. Moreover, the communications system1640or other host system1608components can provide a user interface for a human operator.

In operation, the host system1608sends commands to the imaging electronics1604. The imaging electronics1604in turn provide instructions to the detectors212that configure the detectors212appropriately, and that operates the detectors212to obtain component images232in accordance with the host system1608instructions. Moreover, the host system1608and/or the imaging electronics1604, for example through execution of application programming1624or1644, can operate to fuse component images232obtained by different detectors212into a composite image, where a composite image is an image that incorporates multiple component images. Moreover, the composite image can be a complete image, where a complete image encompasses all of the component images232received at all of the detectors212within the imaging system104during any one image integration period. For example, a complete image can encompass an entire area116within the field of view112of the imaging system104. The host system1608can also perform functions related to operation of the platform108and/or the imaging system104, including but not limited to: operations relating to the positioning of the platform108; receiving and acting on instructions from a command center or user; transmitting component images collected by the imaging system104; transmitting the results of image fusion performed by the imaging electronics1604or the host system1608; and performing actions, including but not limited to actions concerning the positioning of the platform108, autonomously and/or in response to commands received from a remote authority through the communication interface1640.

FIG.17is a flow chart depicting aspects of a method of collecting a composite image formed from multiple component images232in accordance with embodiments of the present disclosure. The method includes collecting multiple overlapping component images232from a selected area116within a scene120. In accordance with at least some operating modes of embodiments of the present disclosure, the component images232for inclusion in a particular composite image are all collected during the same integration period. In accordance with further operating modes of at least some embodiments of the present disclosure, the component images232included in a particular composite image are collected during overlapping integration periods. Initially, the method includes pointing an imaging system104so that a field of view112of the imaging system104encompasses a desired area116of a scene120(step1704). Light from within the field of view112is divided into multiple component images232by field segmentation optics208located between the exit pupil224and the focal plane216of the imaging system104(step1708). The different component images232are directed along different component optical paths, and imaged onto detectors212that are each located at the same focal distance from the exit pupil224. Moreover, the different detectors212can be located on different component focal planes216. The detectors212are then operated to capture the component images (step1712), which may be configured such that all component images are captured simultaneously. For example, the electrical signals generated by arrays of pixels included in the detectors212are stored as representations of the component images.

The multiple component images are then combined to create a composite image. In particular, the stored component images obtained from the detectors212are registered (step1716). Registering the component images can include aligning the component images232relative to one another, including the operations of reorienting the image data (horizontal and/or vertical flip), lateral shifting, rotation, and dimensional compression or expansion. Pre-processing of component images can also include scaling of the image brightness or color data to match signal levels between component images. The registered component images232can then be fused (step1720). Fusing the component images232can include adding image data collected by detector pixels from within overlapping areas128within the imaged area112. The resulting composite image can then be provided as an imaging system104output (step1724). A determination can then be made as to whether operation of the imaging system104should continue (step1728). If operation is to continue, the process can return to step1604. Otherwise, the process can end.

In accordance with at least some embodiments of the present disclosure, the registration and fusion of the multiple image components to generate a composite image can be performed through the execution of application programming1624by the imaging electronics1604processor1620provided as part of the imaging system104, and/or by the execution of application programming1644by the host system1608processor1628. In accordance with further embodiments, some or all of the processing steps can be performed by a system that is separate from the imaging system104.

In accordance with embodiments of the present invention, the process of combining component images232to obtain a composite image can be performed for all or selected portions of the imaged area112. For example, processing time can be reduced by only processing the source pixels contributing signals that will eventually be displayed in a selected viewport or area within the larger imaged area112, as opposed to combining all of the component images232and then extracting a viewport encompassing a selected portion of the larger imaged area112. Alternatively or in addition, the image data included in the component images232can be combined using the entire available image resolution, or at a reduced resolution.

The foregoing discussion of the disclosed systems and methods has been presented for purposes of illustration and description. Further, the description is not intended to limit the disclosed systems and methods to the forms disclosed herein. Consequently, variations and modifications commensurate with the above teachings, within the skill or knowledge of the relevant art, are within the scope of the present disclosure. The embodiments described herein are further intended to explain the best mode presently known of practicing the disclosed systems and methods, and to enable others skilled in the art to utilize the disclosed systems and methods in such or in other embodiments and with various modifications required by the particular application or use. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art.