Space optical remote sensor is to the computer simulation system of actual atural object imaging
Technical field
The present invention relates to a kind of computer simulation system that auxiliary space optical sensor optical property detects in the SPACE APPLICATION field, especially can or stare the system that the formula space optical remote sensor carries out emulation to the atural object imaging process of dimensional topography fluctuating push-broom type under the various spatial attitudes.
Background technology
Space optical remote sensor imaging simulation over the ground is that space optical remote sensor manufactures and designs the important step in the work.At present; To space optical remote sensor over the ground the emulation of imaging process mainly take hardware means: base area revolutions and remote sensor are in the relative motion relation between optical sensor and the terrain object between rail sporting flying state computation clearancen; According to this kinematic relation; Use the relative motion between method virtual space optical sensor such as cylinder, three air floating platforms or pivot arm and the terrain object; The target of space optical remote sensor (or only replacing space optical remote sensor with CCD and some simple optical elements) with the simulation terrain object is installed on the analogue means, realizes the simulation hardware imaging.
But the simulation hardware imaging means has following limitation:
1. owing to limited by physical construction; Remote sensor track and attitude parameter variation range that the simulation hardware platform is simulated are narrower; Under the prerequisite of not revising Design of Mechanical Structure; The space optical remote sensor that is difficult to simulate multiple track and attitude forms images over the ground, especially is difficult to simulate on the elliptical orbit remote sensor imaging process over the ground.
2. because the synchronization accuracy of the machining precision of mechanical part and electronics element limits, the synchronisation mismatch of simulation hardware platform, mechanical vibration equal error are to be difficult to ignore with unavoidable to the interference of simulation imaging.In addition; The simulation hardware platform often is difficult to simulate the influence of the triaxial ellipsoid face face of land of the earth to the image plane surface imaging: most emulation platforms use plane target drone; Some platforms use the template that has three-dimensional rugged topography as the imaging target; But still be difficult to reflect the accurate projection relation of each point scenery position on the image planes each point and the ellipsoid face of land, push away the scope of sweeping because of the ellipsoid face of land that receives the earth influences the pattern distortion situation of change and the atural object that cause thereby be difficult to simulate remotely sensed image.Therefore, the functional limitation of simulation imaging platform is in being main to use planar strip line target to detect the remote sensor image quality at present, and using scenery target checking remote sensor imaging effect is the stage of assisting, and has limited the application of emulation platform in wider field.
3. remote sensing forms images the simulation hardware platform over the ground for satisfying remote sensor and target source layout needs, generally has bigger labyrinth, and has the movable part simulation remote sensor that guarantees one degree of freedom at least and move at rail.If platform has the colourful attitude imaging simulation of remote sensor function, then movable part is more.The complicated machinery parts that have movable part have proposed high requirement to crudy and maintenance work.In addition, the further upgrading to platform is also relatively more difficult.
Summary of the invention
The technical matters that the present invention will solve provides a kind of can the imaging over the ground with any attitude to the space optical remote sensor on the various tracks and carries out emulation, be easy to simultaneously to safeguard and the space optical remote sensor of upgrading to the computer simulation system of actual atural object imaging.
In order to solve the problems of the technologies described above, space optical remote sensor of the present invention comprises target source matching module, remote sensor emulation module, analogue system clock unit, scan module and scanning information molded tissue block to the computer simulation system of actual atural object imaging;
The target source matching module: with atural object brightness data and region altitude figures is input; Atural object ratio adjustment arithmetical unit by inside will be planned to the planning luminance matrix that distributes according to solid angle coordinate in space in the terrestrial coordinate system again according to the atural object brightness data of nature range ring; Elevation matching operation device by inside is planned to and plans the elevation distribution matrix that luminance matrix is supporting with the region altitude figures; To plan that then luminance matrix and elevation distribution matrix merge, and obtain having the atural object brightness and the spatial information integrated data of three-dimensional topography profile information; Atural object brightness and spatial information integrated data offer scan module;
Said remote sensor emulation module comprises orbital simulation unit, attitude-simulating unit, simulation of optical systems unit and imageing sensor analogue unit; The orbital simulation unit is that scan module provides the remote sensor orbit parameter; The attitude-simulating unit is that scan module provides remote sensor at the rail attitude parameter; The simulation of optical systems unit is the focal length that scan module provides the remote sensor optical system, and the point spread function that calculates each sub-visual field of remote sensor optical system according to the remote sensor optical system structure is provided for the scanning information molded tissue block; The imageing sensor analogue unit is the imageing sensor physical parameter that scan module and scanning information molded tissue block provide remote sensor;
Analogue system clock unit: for scan module and scanning information molded tissue block provide time synchronization information;
Said scan module comprises scanning sequence controller, pixel mapping unit, elevation effect coupling unit and exposure analogue unit;
Scanning sequence controller: the imageing sensor physical parameter of utilizing time synchronization information that the analogue system clock unit provides and imageing sensor analogue unit to provide; Obtain the imaging time sequence of each pixel of imageing sensor in the remote sensing of the earth process, and the imaging time sequence of each pixel is offered the pixel mapping unit;
Pixel mapping unit: the imageing sensor physical parameter that the remote sensor orbit parameter that provides according to the orbital simulation unit, the remote sensor attitude parameter that the attitude-simulating unit provides, remote sensor optical system focal length that the simulation of optical systems unit provides and imageing sensor analogue unit provide; Concern the space geometry relation between each pixel of computed image sensor and the ground scenery according to the image space geometry, obtain each pixel at the omnidistance corresponding atural object coordinate sequence of remote sensing process; The imaging time sequence of each pixel of imageing sensor that provides according to planning luminance matrix and the scanning sequence controller of each pixel in the omnidistance corresponding atural object coordinate sequence of remote sensing process, atural object brightness and spatial information integrated data obtains the corresponding ground article coordinate brightness time series of each pixel of imageing sensor; The ground article coordinate brightness time series that each pixel is corresponding offers elevation effect coupling unit;
Elevation effect coupling unit: with elevation distribution matrix in the spatial information integrated data brightness data in the corresponding ground article coordinate brightness time series of each pixel of imageing sensor is carried out interpolation according to atural object brightness; Realize the elevation correction, obtain revising ground article coordinate brightness time series; Revise ground article coordinate brightness time series and offer the exposure analogue unit;
The exposure analogue unit: the each point brightness value carries out the analogue exposure computing in the correction ground article coordinate brightness time series that the imageing sensor physical parameter that provides according to the imageing sensor analogue unit provides elevation effect coupling unit, obtains the image coordinate gray scale time series of each pixel of imageing sensor; The image coordinate gray scale time series of each pixel offers the scanning information molded tissue block;
Scanning information molded tissue block: the image coordinate gray scale time series of each pixel of imageing sensor that time synchronization information, the imageing sensor physical parameter that the imageing sensor analogue unit provides and the analogue unit that makes public that provides according to the analogue system clock unit provides; Arrange out image over the ground; The point spread function convolution of each visual field of optical system that again image of arranging out over the ground and simulation of optical systems unit is provided obtains imaging simulation brightness of image matrix over the ground.
Said pixel mapping unit: utilize formula (1) confirm the spatial attitude of the relative satellite of oblique ray of connector picture (ξ, η);
ζ wherein
0, ξ
0, η
0Be respectively satellite driftage, roll, pitch attitude angle, (x
0, y
0) be each cell coordinate of imageing sensor, F is the optical system focal length of remote sensor;
Utilize formula (2) to calculate oblique ray and satellite---the angle theta of substar line of connector picture;
tan
2θ=tan
2ξ+tan
2η (2)
Utilize formula (3) to calculate between the image apart from l:
Wherein R is an earth radius, and H is that the satellite rail is high; The target model can simulate three-dimensional landform based on the ellipsoid face of land
Utilize formula (4) to calculate the subtended angle
that the face of land connects the airline of substar and scenery
Spatial attitude (ξ according to the relative satellite of oblique ray of
and connector picture; η); Utilize the spherical angle formula to calculate the longitude and latitude that obtains atural object, thereby confirm the space geometry relation between each pixel of imageing sensor and the ground scenery.
Comprise scenery place landform altitude information in the said elevation distribution matrix and on the sphere land-based to the elevation update information on the earth ellipsoid face of land.
Beneficial effect of the present invention:
Can on the wild trajectory arbitrarily the space optical remote sensor of attitude over the ground imaging process carry out emulation.
2. get rid of machinery and electronics error that the simulation hardware platform is introduced, can accurately calculate under the rail environment each corresponding relation of remote sensor image planes each point and atural object constantly; Can carry out imaging simulation to three-dimensional scenery with artificial regulation topographic relief.The target model that adopts can be simulated the three-dimensional landform based on the ellipsoid face of land; The target landform altitude customized justice that distributes, range of choice is wide.Because the every bit of simulation imaging image all calculates acquisition based on the projection relation of three-dimensional landform and image planes, therefore can the projection distortion of atural object on image planes be reflected, and provide accurate imaging scope.Permission defines a plurality of imaging regions on image planes, polylith CCD layout on image planes is carried out emulation.Like this; The present invention not only can provide the simulation scanning image of checking remote sensor image quality; And can provide accurate remote sensor ground surface imaging coverage and atural object projection distortion information; And the scanning result of taking various CCD placement schemes; For the multiple application such as topological design, the exploitation of many scapes remote sensing images splicing and MTFC technological development on image planes of track selection, design of Optical System, imageing sensor provide the simulating, verifying function, widened remote sensor imaging simulation The Application of Technology scope over the ground.
3. module is clear, and compact conformation is easy to upgrade in the face of actual scientific research demand.
Said target source matching module: when the planning luminance matrix, image is adapted to the stretching of image corresponding region longitude and latitude scope at north and south and east-west direction.The simulation result that like this, can prevent the high-latitude area is influenced by the parallel reduced distances and produces distortion.
The imageing sensor physical parameter that said imageing sensor analogue unit provides comprises CCD physical parameter and TDI-CCD physical parameter.
Said scanning information molded tissue block comprises push-broom type imaging OU and stares formula imaging OU; The image coordinate gray scale time series that the time synchronization information that push-broom type imaging OU provides according to the analogue system clock unit, the TDI-CCD physical parameter that the imageing sensor analogue unit provides and analogue exposure unit are produced; Arrange out image over the ground; Point spread function (PSF) convolution of each visual field of optical system that again image of arranging out over the ground and simulation of optical systems unit is provided obtains TDI-CCD imaging simulation brightness of image matrix over the ground; Stare the image coordinate gray scale time series that time synchronization information that formula imaging OU provides according to the analogue system clock unit, CCD physical parameter that the imageing sensor analogue unit provides and analogue exposure unit are produced; Arrange out image over the ground; The point spread function convolution of each visual field of optical system that again image of arranging out over the ground and simulation of optical systems unit is provided obtains CCD imaging simulation brightness of image matrix over the ground.
The imaging mode of space optical remote sensor of the present invention can and be stared between the formula and select at push-broom type, for the push-broom type imaging, can realize the imaging of synchronous scanning accurately, is easy to simultaneously safeguard and upgrading.Be applicable to that TDI-CCD push-broom type and area array CCD stare the emulation of imaging process over the ground of formula remote sensor.
Description of drawings
Below in conjunction with accompanying drawing and embodiment the present invention is described further.
Fig. 1 is the computer simulation system structured flowchart of space optical remote sensor of the present invention to actual atural object imaging.
Fig. 2 target source matching module structured flowchart.
Fig. 3 remote sensor emulation module structured flowchart.
Fig. 4 scan module structured flowchart.
Fig. 5 scanning information molded tissue block structured flowchart.
1. target source matching modules among the figure, 2. remote sensor emulation module, 3. scan module, 4. scanning information molded tissue block; 8. analogue system clock unit, 10. atural object ratio adjustment arithmetical unit, 11. elevation matching operation devices, 12. orbital simulation unit; 13. the attitude-simulating unit, 14. simulation of optical systems unit, 15. imageing sensor analogue units; 16. the scanning sequence controller, 17. pixel mapping unit, 18. elevation effect coupling units; 21. the exposure analogue unit, 19. push-broom types imaging OU, 20. stare formula imaging OU.
Fig. 6 is that the space geometry between each pixel of remote sensor and the ground scenery concerns synoptic diagram.
L is a distance between the image among the figure; R is an earth radius; H is that the satellite rail is high; θ is the oblique ray and the satellite of connector picture---the angle of substar line,
connect the subtended angle of the airline of substar and scenery for the face of land.
Embodiment
As shown in Figure 1, space optical remote sensor of the present invention comprises target source matching module 1, remote sensor emulation module 2, scan module 3, scanning information molded tissue block 4, analogue system clock unit 8 to the computer simulation system of actual atural object imaging.
As shown in Figure 2, said target source matching module 1 comprises atural object ratio adjustment arithmetical unit 10, elevation matching operation device 11.
Target source matching module 1 is input with atural object brightness data and region altitude figures; The form of atural object brightness data for can compatible remote sensing, take photo by plane or manual simulation's two-dimensional image; Image is according to the nature range ring; From brightness of image matrix numerical precision aspect, can be gray bitmap or floating number matrix; From the image spectrum quantitative aspects, can be single spectrum, multispectral or high spectrum.The atural object brightness data can obtain from image file, and the region altitude figures obtains with computer-solution to image.
In target source matching module 1; The atural object brightness data is handled through atural object ratio adjustment arithmetical unit 10: according to the face of land, atural object brightness data place longitude and latitude scope; Again plan the luminance matrix coordinate according to longitude and latitude; Use interpolation algorithm to obtain each point brightness value in the luminance matrix, obtain planning luminance matrix.At planning luminance matrix coordinate time, image is adapted to the stretching of image corresponding region longitude and latitude scope at north and south and east-west direction, like this, the simulation result that can prevent the high-latitude area is influenced by the parallel reduced distances and produces distortion.
The form of region altitude figures is planned to the elevation distribution matrix supporting with luminance matrix for pressing the two-dimentional elevation matrix that natural length engineer's scale or longitude and latitude engineer's scale distribute through elevation matching operation device 11.
Planning luminance matrix and elevation distribution matrix are coupled as atural object brightness and spatial information integrated data.
The atural object brightness data of remote sensing target area and region altitude figures are input in the target source matching module 1; Through ratio adjustment and elevation matching process; Again plan according to space solid angle coordinate in the terrestrial coordinate system; To satisfy the data processing demand in the scan module 3, obtain each point brightness and integrated atural object brightness and the spatial information integrated data of elevation information in the remote sensing target area.
As shown in Figure 3, remote sensor emulation module 2 comprises orbital simulation unit 12, attitude-simulating unit 13, simulation of optical systems unit 14 and imageing sensor analogue unit 15.
Orbital simulation unit 12 adopts semi-major axis of orbit a, orbital eccentricity e, right ascension of ascending node Ω
N, orbit inclination i, polar angle ω
NWith satellite through perigee t constantly
pSix orbital elements definition satellites state of flight in orbit, in the inertial coordinates system of equator, satellite position is at any one time defined by following system of equations:
Wherein f is a true anomaly, and E is an eccentric anomaly, and t is for calculating the moment of satellite position.μ is a geocentric gravitational constant, μ=G * M
e=398600.44km
3/ s
2, G is a universal gravitational constant, M
eBe two body earth equivalent masss, be approximately earth quality.
Attitude-simulating unit 13 uses Euler's square parallactic angle definition remote sensor in the rail attitude.
The optical texture of the 14 pairs of remote sensor optical systems in simulation of optical systems unit carries out emulation, and uses CODEV optical analysis software, calculates the point spread function (PSF) of each sub-visual field of optical system of remote sensor according to the remote sensor optical system structure.
15 couples of CCD of imageing sensor analogue unit and TDI-CCD carry out emulation; For scan module 3 and scanning information molded tissue block 4 provide physical parameters such as CCD fabric width, pixel dimension, line frequency, quantum efficiency, signal to noise ratio (S/N ratio), the inferior physical parameter of fabric width, pixel dimension, line frequency, quantum efficiency, signal to noise ratio (S/N ratio) and integration stages of TDI-CCD is provided for scan module 3 and scanning information molded tissue block 4 perhaps.
Remote sensor emulation module 2 can carry out emulation to the motion feature and the physical characteristics of remote sensor track, attitude, optical system and imageing sensor (comprising CCD and TDI-CCD).Wherein orbital simulation unit 12 can provide remote sensor orbit parameter, remote sensor attitude parameter for scan module 3 with attitude-simulating unit 13.The simulation of optical systems unit can provide the optical system focal length for scan module 3, and the point spread function (PSF) of each sub-visual field of optical system of remote sensor is provided for scanning information molded tissue block 4.Imageing sensor analogue unit 15 provides the imageing sensor physical parameter for scan module 3, comprises fabric width, pixel dimension, line frequency, quantum efficiency, the signal to noise ratio (S/N ratio) of gazing type CCD; The fabric width of TDI-CCD, pixel dimension, line frequency, integration stages time, quantum efficiency, signal to noise ratio (S/N ratio); For scanning information molded tissue block 4 provides fabric width, pixel dimension, the line frequency of gazing type CCD, the fabric width of TDI-CCD, line frequency, pixel dimension, integration stages time.
Analogue system clock unit 8 provides unified benchmark sweep time over the ground for scan module 3 and scanning information molded tissue block 4.
As shown in Figure 4, scan module 3 comprises scanning sequence controller 6, pixel mapping unit 17, elevation effect coupling unit 18 and exposure analogue unit 21.
Scan module 3 obtains the optical system focal length of remote sensor orbit parameter, remote sensor attitude parameter, remote sensor and the physical parameter of imageing sensor from remote sensor emulation module 2, sets up in the whole remote sensing of the earth imaging process each brightness data one-to-one relationship in each point and atural object brightness and the spatial information integrated data constantly of image planes.
Scanning sequence controller 16: the imageing sensor physical parameter that time synchronization information that use analogue system clock unit 8 is provided and imageing sensor analogue unit 15 provide (fabric width, pixel dimension, line frequency, the integration stages that comprise fabric width, pixel dimension, line frequency and the TDI-CCD of CCD are inferior); According to constantly---the rule discharge of staring formula CCD pixel ranks coordinate (or each integration stages cell coordinate of TDI-CCD) concerns the sequence of calculation at the image space geometry of omnidistance each pixel of remotely sensed image process, obtains the imaging time sequence of each pixel of imageing sensor in the remote sensing of the earth process.
Pixel mapping unit 17: the CCD physical parameter (fabric width, the pixel dimension that comprise CCD and TDI-CCD) that the remote sensor orbit parameter that provides according to orbital simulation unit 12, the remote sensor attitude parameter that attitude-simulating unit 13 provides, optical system focal length that simulation of optical systems unit 14 provides and imageing sensor analogue unit 15 provide; Calculate the space geometry relation between each pixel of remote sensor and the ground scenery according to image space geometry relation, obtain each pixel at the omnidistance corresponding atural object coordinate sequence of remote sensing process; The imaging time sequence of each pixel that provides according to planning luminance matrix and the scanning sequence controller 16 of each pixel in omnidistance corresponding atural object coordinate sequence, atural object brightness and the spatial information integrated data of remote sensing process obtains the ground article coordinate brightness time series of each pixel correspondence.
As shown in Figure 6, the space geometry relation between each pixel of remote sensor and the ground scenery (is cell coordinate (x on the image planes
0, y
0) and the longitude and latitude of scenery between the space geometry relation) by following system of equations decision:
Wherein l is a distance between the image; R is an earth radius; H is that the satellite rail is high; θ is the oblique ray and the satellite of connector picture---the angle of substar line,
connect the subtended angle of the airline of substar and scenery for the face of land.
The spatial attitude of the relative satellite of oblique ray of connector picture (ξ, η) confirm by following formula:
(ζ wherein
0, ξ
0, η
0) be satellite driftage, roll, pitch attitude angle, (x
0, y
0) be cell coordinate on the CCD image planes, F is the focal length of remote sensor optical system.
Spatial attitude (ξ according to the relative satellite of oblique ray of
and connector picture; η), utilize the spherical angle formula can calculate the longitude and latitude that obtains atural object.
Elevation effect coupling unit 18: with elevation distribution matrix in the spatial information integrated data brightness data in the corresponding ground article coordinate brightness time series of each pixel of imageing sensor is carried out interpolation according to atural object brightness; Realize the elevation correction, obtain the corresponding ground article coordinate brightness time series of revised CCD pixel.
Exposure analogue unit 21: the quantum efficiency, the signal to noise ratio (S/N ratio) that are provided according to imageing sensor analogue unit 15; The each point brightness value carries out the analogue exposure computing in the corresponding ground article coordinate brightness time series of the revised CCD pixel that elevation effect coupling unit 18 is provided; Realize opto-electronic conversion, obtain the image coordinate gray scale time series that each pixel of CCD is gathered.
As shown in Figure 5, scanning information molded tissue block 4 comprises push-broom type imaging OU 19 and stares formula imaging OU 20; Push-broom type imaging OU 19 and two kinds of imaging modes staring the corresponding remote sensor of formula imaging OU 20 difference.The image coordinate gray scale time series that the time synchronization information that push-broom type imaging OU 19 provides according to analogue system clock unit 8, the CCD fabric width that imageing sensor analogue unit 15 provides, line frequency, pixel dimension, integration stages time and analogue exposure unit 21 are produced; Arrange out image over the ground; Point spread function (PSF) convolution of each visual field of optical system that again image of arranging out over the ground and simulation of optical systems unit is provided; Obtain TDI-CCD imaging simulation brightness of image matrix over the ground, i.e. the simulation imaging file.Stare the image coordinate gray scale time series that time synchronization information that formula imaging OU 20 provides according to analogue system clock unit 8, CCD fabric width, line frequency, pixel dimension and analogue exposure unit that the imageing sensor analogue unit provides are produced; Arrange out image over the ground; Point spread function (PSF) convolution of each visual field of optical system that again image of arranging out over the ground and simulation of optical systems unit is provided; Obtain CCD imaging simulation brightness of image matrix over the ground, i.e. the simulation imaging file.