Disclosure of the invention
The embodiment of the invention aims to provide a space heterodyne interference imaging method and device based on a coded aperture, which improve the stability and high flux of spectral imaging
The purpose of the embodiment of the invention is realized by the following technical scheme:
a space heterodyne interference imaging method based on a coded aperture comprises the following steps:
a1, the interference imaging platform drives the imaging system to move relative to the scenery;
a2, sequentially passing through a front mirror, a collimating mirror, a grating, an imaging mirror, a coding template, an imaging mirror and a detector;
a3, making the interference spectrum data cube of the scenery enter a coding template for modulation after passing through an imaging mirror L2, and traversing the interferogram line by the coding template;
a4, the encoded interference pattern passes through an imaging mirror L3 and then is detected by a detector to obtain encoded interference data.
The utility model provides a space heterodyne interference imaging device based on coded aperture, including imaging platform and with the fixed imaging system of platform, imaging system is including the leading warp that sets gradually, collimating mirror, grating, coding template, imaging mirror and detector, imaging system with imaging platform is fixed, and imaging platform is used for driving the relative scenery of imaging system and carries out horizontal migration.
According to the technical scheme provided by the embodiment of the invention, the imaging system is formed by the front lens, the collimating lens, the beam splitter, the grating, the coding template, the imaging lens and the detector, the imaging system is fixed on the spectral imaging platform, no moving part is arranged in the platform, and the push-broom type interference imaging system is formed.
(V) detailed description of the preferred embodiments
The technical solutions in the embodiments of the present invention will be described below in detail and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments.
As shown in fig. 1, the spatial heterodyne interference imaging method based on a coded aperture in the embodiment of the present invention includes:
a1, the interference imaging platform drives the imaging system to move relative to the scenery;
a2, sequentially passing through a front mirror, a collimating mirror, a grating, an imaging mirror, a coding template, an imaging mirror and a detector;
a3, making the interference spectrum data cube of the scenery enter a coding template for modulation after passing through an imaging mirror L2, and traversing the interferogram line by the coding template;
a4, the encoded interference pattern passes through an imaging mirror L3 and then is detected by a detector to obtain encoded interference data.
One skilled in the art will appreciate that the optical axis of the imaging system may be the axis of symmetry of the system.
The imaging system and the pre-lens, the collimating lens, the beam splitter, the grating, the coding template, the imaging lens and the detector included in the imaging system can be understood by referring to the prior art, for example, the target light can be converged to a primary image surface after passing through the pre-lens, and then is split into two beams of interference light after passing through the beam splitter, and the two beams of interference light are superposed and enter the plane of the coding template to coincide with each other, and the target image reaches the imaging lens after being coded and modulated by the coding template, and then is imaged by the detector after being imaged by the imaging lens, so that the interference spectrum data modulated by the coding template can be obtained.
The interference imaging platform can be a flat plate type or a frame type, and the like, and the technical personnel in the field can understand that the interference imaging platform is used for installing and rotating a fixed imaging system, the interference imaging platform drives the imaging system to push and sweep relative scenery, the structure of the interference imaging platform is not limited, the installation mode of the interference imaging platform and the imaging system is not limited, the spectrum imaging platform is used for installing and rotating the fixed imaging system, the imaging system can be directly installed and is installed on the interference spectrum imaging platform through a frame.
According to the technical scheme provided by the embodiment of the invention, the imaging system is composed of the front mirror, the collimating mirror, the beam splitter, the grating, the coding template, the imaging mirror and the detector, the imaging system is fixed on the interference imaging platform, no moving part is arranged in the platform, and the push-broom interference imaging system is formed.
The embodiment of the invention discloses a space heterodyne interference imaging method based on a coded aperture, which solves the problem that the existing space heterodyne interference imaging spectrometer is low in stability and reliability. The embodiment of the invention designs and perfects the motion form and the imaging mode of the system based on the spatial heterodyne interference imaging method of the coded aperture, so that a coded template, a grating, a detector and related optical elements (a front warp, a collimating warp, an imaging mirror and the like) jointly form an imaging system, and the imaging system is installed and an imaging platform, thereby realizing the integral push-broom imaging of the platform and improving the stability and the reliability of the system.
As shown in fig. 2, corresponding to the spatial heterodyne interference imaging method based on coded aperture in the foregoing embodiment, an embodiment of the present invention provides a spatial heterodyne interference imaging apparatus based on coded aperture, which includes an interference imaging platform and an imaging system fixed thereto, where the imaging system includes a front mirror, a coding template, a collimating mirror, a grating, an imaging mirror and a detector, which are arranged at one time, the imaging system is fixed to the interference imaging platform, and the interference imaging platform is configured to drive the imaging system to move horizontally with respect to a scene.
One skilled in the art will appreciate that the optical axis of the imaging system may be the axis of symmetry of the system.
The imaging system and the front mirror, the collimating mirror, the beam splitter, the grating, the coding template, the imaging mirror and the detector included in the imaging system can be understood by referring to the prior art, for example, the imaging system can be understood by referring to the prior spatial heterodyne interference imaging spectrometer, for example, a target light is converged to a primary image surface after passing through the front mirror, is divided into two beams of interference light after passing through the beam splitter, is superposed and enters the coding template plane for superposition, a target image is coded and modulated by the coding template, reaches the imaging mirror, is imaged by the imaging mirror and then is imaged by the detector, and interference pattern data modulated by the coding template are obtained.
The interference imaging platform can be a flat plate or a frame, and the like, and the technical personnel in the field can understand that the interference imaging platform is used for installing and rotating a fixed imaging system, the interference imaging platform drives the imaging system to push and sweep relative scenery, the structure of the interference imaging platform is not limited, the installation mode of the interference imaging platform and the imaging system is not limited, the interference imaging platform is used for installing and rotating the fixed imaging system, the imaging system can be directly installed, and the interference imaging platform is installed on the interference imaging platform through the frame.
According to the technical scheme provided by the embodiment of the invention, the imaging system is composed of the front lens, the collimating lens, the beam splitter, the grating, the coding template, the imaging lens and the detector, the imaging system is fixed on the interference imaging platform, no moving part is arranged in the platform, and the push-broom interference imaging system is formed.
Optionally, the interference direction of the grating is the same as the row direction of the encoding template, or the interference direction of the grating is the same as the column direction of the encoding template.
It will be appreciated by those skilled in the art that the interference direction of the grating coincides with the row or column direction of the encoding template, but only one direction can be selected to remain coincident to ensure interference superposition in only one direction.
Optionally, the moving direction of the imaging system is perpendicular to the interference direction of the grating.
Those skilled in the art will appreciate that the interference angle can be changed by rotating the grating along the optical axis, which is not described in detail herein.
The purpose of the change of the interference angle is to ensure that the interference angle is vertical to the overall moving direction of the imaging system, at the moment, the coding template moves synchronously with the system, so that the relative movement between each line of the coding template and a target can be ensured, and the interference influence on other lines can not be generated.
Specifically, when the interference direction of the grating is consistent with the row direction of the encoding template, the interference data cube of the scenery traverses line by line along the encoding template, and interference data are obtained on the detector after the grating, which may include:
the interference data cube moves 1 line along the direction vertical to the grating, the line N-1 of the interference data cube is modulated by the line N of the corresponding coded template, and the coded interference data is formed on the line N of the detector, wherein N is larger than or equal to 2.
The space heterodyne interference imaging device based on the coded aperture of the embodiment of the invention solves the defects of low stability and reliability of the existing space heterodyne spectrum imager, designs and perfects the system motion form and the imaging mode, so that a coded template, a grating, a detector and corresponding optical elements (a front lens, a collimating lens, an imaging lens and the like) jointly form an imaging system, a residual imaging platform is installed, the integral push-broom imaging of the platform is realized, and the stability and reliability of the system are improved.
As shown in fig. 3, in the embodiment of the present invention, in a detection process of a spatial heterodyne interference imaging apparatus based on a coded aperture:
the coding template, the detector and related optical elements (a front lens, a collimating lens, an imaging lens and the like) jointly form an imaging system, and a spectrum subjected to grating interference is modulated by the coding template to obtain a required modulated data cube. I.e. a series of interference patterns obtained by continuous push-broom, and recoded by the coding template to obtain and store the required image sequence.
The push-broom coded aperture-based spatial heterodyne interference imaging system can realize the transformation of different coding modes through the whole push-broom platform, the coding template is fixed in the system, and all parts in the imaging system do not need to move, so that the stability of the whole imaging system is higher.
The above description shows that the spatial heterodyne interference imaging method and device based on the coded aperture mainly solve the problem that the current spatial heterodyne interference imager needs staring imaging and is difficult to apply to the field of space remote sensing while keeping the advantages of high throughput, high signal-to-noise ratio and the like, and improve the internal structure of the system by adjusting the imaging mode, thereby improving the stability and universality of the spectral imaging system.
Compared with the existing spatial heterodyne interference imaging system, the spatial heterodyne interference imaging method and device based on the coded aperture in the embodiment of the invention have the following characteristics:
(1) interference direction change
The interference direction is changed by rotating the light splitting element along the optical axis, the purpose is to ensure that the interference direction is vertical to the integral moving direction of the imaging system, in addition, the coding template moves synchronously with the system, the relative movement between each line of the coding template and the target can be ensured, and the interference aliasing influence on other lines can not be generated.
(2) Coded imaging modality change
And the data obtained on the detector is subjected to one-time superposition of signals obtained by line-by-line push scanning to form aliasing two-dimensional data, and finally, the aliasing data is subjected to inversion and reconstruction to recover and obtain a three-dimensional spectral data cube. For the N-dimensional coding template, each frame of observation result corresponds to one N-element linear equation, the coding mode is changed by pushing and sweeping the imaging system, so that multiple times of coding modulation are carried out, and multiple groups of N-element linear equations are obtained through observation. When the coefficient matrix corresponding to the coding template is an orthogonal matrix, the map data can be completely reconstructed; when the coefficient matrixes are not completely orthogonal, the optimal solution can be solved by adding limiting conditions through some algorithms, so that a high-quality map is reconstructed, and the method has flexible selectivity.
Although the present invention has been described in detail with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims. The techniques, shapes, and structural parts not described in detail in the present invention are all known techniques.