CN115793348A - Target enhancement up-conversion imaging method and system - Google Patents
Target enhancement up-conversion imaging method and system Download PDFInfo
- Publication number
- CN115793348A CN115793348A CN202211542509.XA CN202211542509A CN115793348A CN 115793348 A CN115793348 A CN 115793348A CN 202211542509 A CN202211542509 A CN 202211542509A CN 115793348 A CN115793348 A CN 115793348A
- Authority
- CN
- China
- Prior art keywords
- light
- fourier lens
- target
- fourier
- conversion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Landscapes
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
The invention discloses a target enhancement up-conversion imaging method and a target enhancement up-conversion imaging system, relates to the field of optics, and is used for solving the problem that the signal-to-noise ratio of target information in the existing image communication is low. The target enhancement up-conversion imaging method comprises the following steps: carrying out Fourier transform on infrared light carrying target information, and taking a result after the Fourier transform as signal light; the method comprises the following steps of taking a super-Gaussian structure light beam with a central hole positioned in an infrared light wave band as pump light; injecting signal light and pump light into a nonlinear crystal to generate nonlinear action, and realizing low-frequency trapping of the signal light through the nonlinear action so as to excite and generate an up-conversion optical field of a visible light wave band; and performing inverse fourier transform on the up-converted light field to obtain a target enhanced target light field in the visible light band. A target enhanced up-conversion imaging system is used to implement the above method. The above-described techniques of the present invention can be used to enhance the signal-to-noise ratio of target information in image communications.
Description
Technical Field
The invention relates to the technical field of optics, in particular to a target enhancement up-conversion imaging method and a target enhancement up-conversion imaging system.
Background
Infrared imaging technology has important applications in many popular fields, including biomedical detection, aerospace remote sensing monitoring, military reconnaissance, agricultural product detection, security monitoring systems, automotive night vision systems, and the like. It can be seen that the above applications require, without exception, the processing of background (temperature) noise in the natural environment in order to make the observed target clearer. However, in the existing infrared imaging or communication technology field, the signal-to-noise ratio obtained by the technology is relatively low, and therefore, there is a need to provide a technology capable of improving the signal-to-noise ratio of the target information in the infrared imaging or communication.
Disclosure of Invention
To this end, the present invention provides a target enhanced up-conversion imaging method and system, which aim to solve or at least alleviate the problem of low signal-to-noise ratio of target information in the existing infrared imaging or image communication.
According to a first aspect of the present invention, there is provided a method of target enhanced up-conversion imaging, the method comprising: fourier transformation is carried out on infrared light carrying target information, and the result of Fourier transformation on the infrared light carrying the target information is used as signal light; the method comprises the following steps of taking a super-Gaussian structure light beam with a central cavity positioned in an infrared light wave band as pump light; injecting the signal light and the pump light into a nonlinear crystal to generate a nonlinear effect, and realizing low-frequency trapping of the signal light through the nonlinear effect to excite and generate an up-conversion optical field of a visible light wave band; and performing inverse Fourier transform on the up-converted light field to obtain a target enhanced target light field of the visible light band.
Further, the method is realized based on a target enhanced up-conversion imaging system, which comprises a first phase type spatial light modulator, a second phase type spatial light modulator, a nonlinear crystal, a first Fourier lens, a second Fourier lens, a third Fourier lens, a fourth Fourier lens, a fifth Fourier lens, a sixth Fourier lens, a seventh Fourier lens, a reflecting mirror and a detector; the signal light is loaded with target information after passing through the first phase type spatial light modulator, is imaged by the first Fourier lens and the second Fourier lens, is transmitted by the first dichroic mirror and then is subjected to standard Fourier transform by the sixth Fourier lens to obtain signal light for entering the nonlinear crystal; the pump light is incident to the nonlinear crystal after passing through two 4f imaging systems consisting of a third Fourier lens, a fourth Fourier lens, a fifth Fourier lens and a sixth Fourier lens; and the pump light and the signal light generate a second-order nonlinear effect in the nonlinear crystal to obtain an up-conversion light field, the up-conversion light field is separated from the pump light and the signal light through a second dichroic mirror, and the separated up-conversion light field is subjected to space Fourier inverse transformation through a seventh Fourier lens to obtain a target light field after target enhancement so as to be received through a detector.
Further, the signal light wavelength is 1550nm, and the pump light wavelength is 780nm; the working wavelength of the first phase type spatial light modulator is matched with the wavelength of the signal light, and the working wavelength of the second phase type spatial light modulator is matched with the wavelength of the pump light.
Further, the target information is image information for communication.
According to a second aspect of the present invention, there is also provided a target enhanced up-conversion imaging system, comprising: the phase-type spatial light modulator comprises a first phase-type spatial light modulator, a second phase-type spatial light modulator, a nonlinear crystal, a first Fourier lens, a second Fourier lens, a third Fourier lens, a fourth Fourier lens, a fifth Fourier lens, a sixth Fourier lens, a seventh Fourier lens, a reflector and a detector; the signal light is loaded with target information after passing through the first phase type spatial light modulator, is imaged by the first Fourier lens and the second Fourier lens, is transmitted by the first dichroic mirror and then is subjected to standard Fourier transform by the sixth Fourier lens to obtain signal light for entering the nonlinear crystal; the pump light is incident to the nonlinear crystal after passing through two 4f imaging systems consisting of a third Fourier lens, a fourth Fourier lens, a fifth Fourier lens and a sixth Fourier lens; and the pump light and the signal light generate a second-order nonlinear effect in the nonlinear crystal to obtain an up-conversion light field, the up-conversion light field is separated from the pump light and the signal light through a second dichroic mirror, and the separated up-conversion light field is subjected to space Fourier inverse transformation through a seventh Fourier lens to obtain a target light field after the target is enhanced so as to be received through a detector.
Further, the signal light wavelength is 1550nm, and the pump light wavelength is 780nm; the working wavelength of the first phase type spatial light modulator is matched with the wavelength of the signal light, and the working wavelength of the second phase type spatial light modulator is matched with the wavelength of the pump light.
Further, the target information is image information for communication.
According to the target enhanced up-conversion imaging method and system, a structural light field with an infrared band with a special spatial morphology, which is constructed by a complex amplitude modulation means (such as a spatial light modulator or a binary optical element), is used as pump light, a Fourier light field (namely a frequency spectrum plane) obtained after spatial Fourier transform is performed on light beams which are also located in the infrared band and carry target information is used as signal light, so that second-order nonlinear sum frequency effect occurs in a nonlinear crystal in two light beams, the pump light performs intensity modulation for realizing low-frequency trap effect on the signal light, and an up-conversion light field located in a visible light band is excited; and then, after the Fourier lens is used for carrying out space Fourier inverse transformation on the up-conversion light field, a target light field with space background noise removed can be obtained on a focal plane behind the lens, and therefore the signal to noise ratio of target information is improved.
Drawings
To the accomplishment of the foregoing and related ends, certain illustrative aspects are described herein in connection with the following description and the annexed drawings, which are indicative of various ways in which the principles disclosed herein may be practiced, and all aspects and equivalents thereof are intended to be within the scope of the claimed subject matter. The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description read in conjunction with the accompanying drawings. Throughout this disclosure, like reference numerals generally refer to like parts or elements.
FIG. 1 is a flow chart illustrating one possible process of a target enhanced up-conversion imaging method according to an embodiment of the present invention;
FIG. 2 is a schematic diagram showing the principle of denoising, denoising based on up-conversion imaging technique, and target-enhanced up-conversion imaging technique in a linear imaging process;
FIG. 3 is a demonstration experiment light path diagram showing a target enhanced up-conversion imaging method;
fig. 4 is a schematic diagram showing experimental results of a target enhanced up-conversion imaging method.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
An embodiment of the present invention provides a target enhanced up-conversion imaging method, including: fourier transformation is carried out on infrared light carrying target information, and a result obtained after Fourier transformation is carried out on the infrared light carrying the target information is used as signal light; the method comprises the following steps of taking a super-Gaussian structure light beam with a central cavity positioned in an infrared light wave band as pump light; injecting signal light and pump light into a nonlinear crystal to generate nonlinear action, and realizing low-frequency trapping of the signal light through the nonlinear action so as to excite and generate an up-conversion optical field of a visible light wave band; and performing inverse fourier transform on the up-converted light field to obtain a target enhanced target light field in the visible light band.
Fig. 1 shows a flow chart of a method of target enhanced up-conversion imaging according to an embodiment of the invention.
As shown in fig. 1, in step S1, the infrared light carrying the target information is fourier-transformed, and the transformed light is used as signal light; the pump light is a super-gaussian structured beam with a central cavity in the infrared light band.
In step S2, the signal light and the pump light are incident into the nonlinear crystal to generate a nonlinear effect, and a low-frequency notch is implemented on the signal light through the nonlinear effect, so as to excite and generate an upconversion optical field in the visible light band.
In step S3, the up-converted light field is subjected to an inverse fourier transform to obtain a target enhanced target light field in the visible wavelength band.
The second-order optical nonlinearity sum frequency effect refers to an effect that two monochromatic lights with different frequencies simultaneously enter a nonlinear medium and excite an upconversion optical field with a frequency equal to the sum of the frequencies of the two light beams (that is, the frequency of the upconversion optical field is equal to the sum of the frequencies of the two light beams). In a Cartesian coordinate system { x, y, z }, under phase matching conditions (i.e., ω is satisfied) 3 ＝ω 1 +ω 2 ) Frequency of ω 1 And omega 2 The two beams of monochromatic light generate a frequency omega 3 The sum frequency effect of the upconversion optical field of (a) can be expressed as:
where E (x, y, ω) is the spatial complex amplitude of the corresponding beam, e.g., E S (x,y,ω 1 ) (i.e., E (x, y, ω) shown in FIG. 3 1 ) ) represents the frequency ω 1 Corresponding to the spatial complex amplitude of the beam, E P (x,y,ω 2 ) (i.e., E (x, y, ω) shown in FIG. 3 2 ) ) represents the frequency ω 2 Corresponding to the spatial complex amplitude of the beam, and E SFG (x,y,ω 3 ) (i.e., E (x, y, ω) shown in FIG. 3 3 ) ) represents the frequency ω 3 The spatial complex amplitude of the corresponding beam; i represents an imaginary unit. Wherein the lower subscript S denotes corresponding to the signal light, the lower subscript P denotes corresponding to the pump light, and the lower subscript SFG denotes corresponding to the up-conversion optical field.
L is the effective nonlinear length, k 3 The wavevector of the up-converted optical field, c the speed of light in vacuum,
is the second order effective nonlinear susceptibility.
In actual space, an image generally has background (temperature) noise with little fluctuation, the noise is represented as low-frequency information concentrated near the center in a frequency spectrum of the image, and the signal to noise ratio of the target information can be improved by operating the frequency spectrum of the target image and properly filtering the low-frequency part of the target image, so that the imaging effect of target enhancement is realized.
Fig. 2 is a schematic diagram illustrating the principle of denoising, denoising based on up-conversion imaging technique, and target enhancement up-conversion imaging technique in the linear imaging process.
Referring to fig. 2, a conventional process of removing background noise in linear imaging is shown in fig. 2 (a), which filters out low frequencies, for example, by using a dark field method or the like, and does not involve frequency conversion. As shown in fig. 2 (a), the original image complex amplitude is represented by E (x, y, ω) (that is, the image before processing corresponds to the light frequency ω), and after fourier transform, a spatial frequency spectrum is obtained
And then filtering a low-frequency part by the operation and performing inverse Fourier transform to obtain a denoised image, wherein the complex amplitude is represented by E' (x, y, omega) (namely the frequency of light corresponding to the finally obtained image after processing is also omega).
The process of removing spatial noise in upconversion imaging according to the present invention is shown in fig. 2 (b), and the operation of enhancing a target image can be achieved while performing wavelength conversion by using an optical nonlinear effect and a structural pump light. As shown in fig. 2 (b), the original image restoration amplitude is E (x, y, ω) 1 ) Representation (i.e. the frequency of light corresponding to the image before processing is ω 1 ) And complex amplitude E (x, y, ω) 2 ) (corresponding to a light frequency of ω 2 ) Exciting an up-conversion light field after the pump light generates sum frequency effect, and obtaining a denoised image through inverse Fourier transform, wherein the complex amplitude is E' (x, y, omega) 3 ) Representation (i.e. the frequency of the light corresponding to the image finally obtained after processing is ω 3 )。
The spatial intensity distribution of the pump light with the structure used in the present invention is shown as (c 3) in fig. 2, and is an ultra-gaussian light beam with a central cavity, when the signal light spectrum shown as (c 2) in fig. 2 and the pump light generate sum frequency effect in the nonlinear crystal, the pump light beam can modulate the intensity of the signal light spectrum, and the cavity has a smoothly varying edge with gaussian distribution characteristics, and will not generate extra frequency oscillation while playing the effect of "low frequency notch", so that the up-conversion optical field loses a part of low frequency information (i.e. bottom noise is removed). The obtained up-converted optical field is subjected to inverse spatial fourier transform, and an image subjected to the target enhancement processing is obtained, as shown in (c 5) in fig. 2.
As an example, the above-mentioned target enhanced up-conversion imaging method of the present invention can be implemented based on a target enhanced up-conversion imaging system, which can adopt a structure as shown in fig. 3. As shown in fig. 3, the system includes a first phase-type spatial light modulator SLM1, a second phase-type spatial light modulator SLM2, a nonlinear crystal PPKTP, a first fourier lens L1, a second fourier lens L2, a third fourier lens L3, a fourth fourier lens L4, a fifth fourier lens L5, a sixth fourier lens L6, a seventh fourier lens L7, a mirror M, a first dichroic mirror DM1, a second dichroic mirror DM2, and a detector CCD.
Non-linear crystals include, for example, but are not limited to, PPKTP (periodically poled potassium titanyl phosphate crystal), and the detector may be a CCD detector, or other types of photodetectors.
The signal light (the wavelength of which is 1550nm, for example) is subjected to loading of target information by the first phase type spatial light modulator SLM1, imaging by the first fourier lens L1 and the second fourier lens L2, transmission by the first dichroic mirror DM1, and then standard fourier transform by the sixth fourier lens L6, so as to obtain the signal light for the incident nonlinear crystal. Wherein E (x, y, ω) is shown in FIG. 3 1 ) Representing the spatial complex amplitude of the signal light.
The pump light (whose wavelength is, for example, 780 nm) passes through two 4f imaging systems including a third fourier lens L3, a fourth fourier lens L4, a fifth fourier lens L5, and a sixth fourier lens L6, and then is incident on the nonlinear crystal PPKTP.
That is, referring to fig. 3, 780nm infrared light is modulated by the SLM2 to obtain desired structured light, such as a super-gaussian structured beam with a central hole, as pump light; after the pump light passes through a 4f imaging system composed of a third Fourier lens L3 and a fourth Fourier lens L4, the pump light is transmitted by a fifth Fourier lens L5, reflected by a reflector M and reflected by a first dichroic mirror DM1 in sequence, and then is incident to a sixth Fourier lens L6, namely, the pump light passes through a 4f imaging system composed of the fifth Fourier lens L5 and the sixth Fourier lens L6, and is imaged into a nonlinear crystal PPKTP.
Wherein E (x, y, ω) is shown in FIG. 3 2 ) Representing the spatial complex amplitude of the pump light.
The pump light and the signal light generate a second-order nonlinear effect in the nonlinear crystal to obtain an up-conversion light field, the up-conversion light field is separated from the pump light and the signal light through a second dichroic mirror DM2, the separated up-conversion light field is subjected to space Fourier inverse transformation through a seventh Fourier lens L7 to obtain a target light field after target enhancement, and the target light field is received through a CCD (charge coupled device) (as an example of a detector). Wherein E (x, y, ω) 3 ) Representing the complex amplitude of the upconverted light field at a wavelength of 520nm corresponding to the sum frequency light.
For example, the signal light wavelength is 1550nm, and the pump light wavelength is 780nm; the working wavelength of the first phase type spatial light modulator is matched with the wavelength of the signal light, and the working wavelength of the second phase type spatial light modulator is matched with the wavelength of the pumping light.
As an example, the target information may include, but is not limited to, image information for communication, for example.
Embodiments of the present invention also provide a target enhanced up-conversion imaging system, including: the phase-type spatial light modulator comprises a first phase-type spatial light modulator, a second phase-type spatial light modulator, a nonlinear crystal, a first Fourier lens, a second Fourier lens, a third Fourier lens, a fourth Fourier lens, a fifth Fourier lens, a sixth Fourier lens, a seventh Fourier lens, a reflector and a detector; the signal light is loaded with target information after passing through the first phase type spatial light modulator, is imaged by the first Fourier lens and the second Fourier lens, is transmitted by the first dichroic mirror and then is subjected to standard Fourier transform by the sixth Fourier lens to obtain signal light for entering the nonlinear crystal; the pump light is incident to the nonlinear crystal after passing through two 4f imaging systems formed by a third Fourier lens, a fourth Fourier lens, a fifth Fourier lens and a sixth Fourier lens; and the pump light and the signal light generate a second-order nonlinear effect in the nonlinear crystal to obtain an up-conversion light field, the up-conversion light field is separated from the pump light and the signal light through the second dichroic mirror, the separated up-conversion light field is subjected to space inverse Fourier transform through the seventh Fourier lens to obtain a target light field after the target is enhanced, and the target light field is received through the detector. The target enhanced up-conversion imaging system may have the same structure as the target enhanced up-conversion imaging system described above with reference to fig. 3, and can achieve similar effects, which are not described herein again.
As an example, the signal light wavelength is 1550nm, and the pump light wavelength is 780nm; the working wavelength of the first phase type spatial light modulator is matched with the wavelength of the signal light, and the working wavelength of the second phase type spatial light modulator is matched with the wavelength of the pump light.
As an example, the target information is image information for communication.
A technical demonstration example based on a liquid crystal phase modulation type-spatial light modulator will be described below with reference to fig. 2 to 4 as a preferred embodiment of the present invention.
As shown in fig. 3, the optical path core component of the demonstration apparatus includes a phase type Spatial Light Modulator (SLM) (e.g., includes a first phase type spatial light modulator SLM1 and a second phase type spatial light modulator SLM 2), a nonlinear crystal PPKTP, and a fourier lens. The laser beams with wavelength of 1550nm and 780nm, and beam waist radius of 1.1mm are used as light source, wherein 1550nm is used as signal light, 780nm is used as pump light, and the two beams of light are respectively incident (such as reflected by a reflector, not shown in the figure) to the SLM surface with working wavelength at corresponding wavelength.
After the signal light passes through the SLM1 and is loaded with object information (i.e., the target information described above), a magic cube image with background noise can be selected as the object information, and the light intensity distribution thereof is shown in (c 1) of fig. 2, and the complex amplitude thereof is e.g. target (x′,y′,ω 1 ). Then, the signal light is imaged by two fourier lenses (i.e., a first fourier lens L1 and a second fourier lens L2), transmitted by a first dichroic mirror DM1, and then subjected to standard fourier transform by a fourier lens (i.e., a sixth fourier lens L6)The inner lobe is transformed to obtain the signal light of the incident nonlinear crystal
Wherein the content of the first and second substances,
the operation means fourier transform of light having complex amplitude a, where coordinates (x ', y') represent spatial coordinates before fourier transform and coordinates (x, y) represent frequency domain coordinates after fourier transform. The light intensity distribution is shown in (c 2) of fig. 2, and a dB coordinate is adopted for the light intensity distribution in order to make the Fourier light field structure clearly visible. The lower-footer target represents target information, e.g. E target (x′,y′,ω 1 ) The complex amplitude of the signal light before fourier transform, which carries the target information, is represented.
The spatial profile of the pump light is shown in (c 3) of FIG. 2, and the complex amplitude is recorded as E P (x,y,ω 2 ) The nonlinear crystal is incident after passing through two 4f imaging systems (namely, a third Fourier lens L3 and a fourth Fourier lens L4 form one 4f imaging system, and a fifth Fourier lens L5 and a sixth Fourier lens L6 form the other 4f imaging system). Wherein M is a mirror. In fig. 2 (c 3), the ordinate represents the normalized optical field intensity (dimensionless) and the abscissa represents the optical field transverse dimension (in mm), which schematically represents the pump light profile.
As shown, the SLM2 complex amplitude modulates (including both amplitude and phase, or may just modulate amplitude) the pump light to become the desired structured light. The SLM1 performs pure intensity modulation (no phase) on the signal light so that its spatial intensity distribution becomes the desired object shape.
The pump light is imaged into the nonlinear crystal (without fourier transform) through two 4f imaging systems. The sixth lens is designed to have an optical path distance so that the sixth lens can not only serve as the last lens of the second 4f system of the pump light, but also play a role in performing standard fourier transform on the signal light. The sixth lens is shared by the signal light and the pump light, but the respective functions are different, and the signal light is subjected to the standard fourier transform, and the pump light exists as the last lens of the 4f system.
The pump light and the signal light generate second-order nonlinear effect in the nonlinear crystal, and an up-conversion light field E is excited according to the relation shown in formula (1) SFG (x,y,ω 3 ) The light intensity distribution is shown in (c 4) of fig. 2, and the dB coordinate thereof is also used.
The second dichroic mirror DM2 is used for separating the up-conversion light field from the signal light and the pump light (the signal and the pump light are received by a trap TR1 in the figure), the seventh Fourier lens L7 is used for carrying out space Fourier inverse transformation on the obtained up-conversion light field, and the target light field after target enhancement and the complex amplitude thereof are obtained
The light intensity distribution is shown in figure 2 (c 5),
the operation means that light with complex amplitude a is subjected to inverse fourier transform. The spatial intensity distribution of the upconverted light field was observed using a CCD camera (i.e. a CCD as described earlier) and the experimental results are shown in fig. 4.
Referring to fig. 4, (a) of fig. 4 is an experimentally generated light intensity distribution of the target object, that is, target information loaded on the signal light, and it can be seen from (a) of fig. 4 that there is obviously a background noise of a circular area around the magic cube; and (b) of fig. 4 is the light intensity distribution of the experimentally generated up-converted light field. By comparing (b) and (a) in fig. 4, it can be seen that the background noise in the upconverted light field is significantly reduced.
It can be seen from the above demonstration example that the upconversion imaging method for realizing target enhancement provided by the invention can effectively filter background noise of a target object in upconversion imaging while converting an infrared band into a visible light wavelength, so that the signal-to-noise ratio of the target object is enhanced.
According to the technology, the pumping light beam with a specific spatial complex amplitude (including intensity and phase) structure is utilized to perform frequency up-conversion operation (namely, second-order nonlinear sum frequency) on the Fourier spectrum surface of a signal image, so that background noise is filtered while up-conversion is realized, and the signal-to-noise ratio of target information is enhanced. The infrared detector can break through the limitation bottleneck of performance and application of the infrared detector, and converts an infrared band into a visible band (an up-conversion imaging technology) by utilizing a second-order optical nonlinear effect and then performs photoelectric conversion detection. The technology can realize high signal-to-noise ratio detection on the infrared target by utilizing a visible silicon-based detector with low cost and high performance in a non-refrigeration environment.
In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
As used herein, unless otherwise specified the use of the ordinal adjectives "first", "second", "third", etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this description, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Furthermore, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter.
Claims (7)
1. A method of target enhanced up-conversion imaging, the method comprising:
fourier transformation is carried out on infrared light carrying target information, and the result of Fourier transformation on the infrared light carrying the target information is used as signal light; the method comprises the following steps of taking a super-Gaussian structure beam with a central cavity and positioned in an infrared light wave band as pump light;
injecting signal light and pump light into a nonlinear crystal to generate nonlinear action, and realizing low-frequency trapping of the signal light through the nonlinear action so as to excite and generate an up-conversion optical field of a visible light wave band; and
performing an inverse Fourier transform on the upconverted light field to obtain a target enhanced target light field in the visible light band.
2. The method for enhanced up-conversion imaging of an object according to claim 1, wherein the method is implemented based on an enhanced up-conversion imaging system of an object, the system comprising a first phase-type spatial light modulator, a second phase-type spatial light modulator, a nonlinear crystal, a first fourier lens, a second fourier lens, a third fourier lens, a fourth fourier lens, a fifth fourier lens, a sixth fourier lens, a seventh fourier lens, a mirror, a first dichroic mirror, a second dichroic mirror, and a detector;
the signal light is loaded with target information after passing through the first phase type spatial light modulator, is imaged by the first Fourier lens and the second Fourier lens, is transmitted by the first dichroic mirror and then is subjected to standard Fourier transform by the sixth Fourier lens to obtain signal light for entering the nonlinear crystal;
the pump light is incident to the nonlinear crystal after passing through two 4f imaging systems formed by a third Fourier lens, a fourth Fourier lens, a fifth Fourier lens and a sixth Fourier lens;
and the pump light and the signal light generate a second-order nonlinear effect in the nonlinear crystal to obtain an up-conversion light field, the up-conversion light field is separated from the pump light and the signal light through a second dichroic mirror, and the separated up-conversion light field is subjected to space Fourier inverse transformation through a seventh Fourier lens to obtain a target light field after the target is enhanced so as to be received through a detector.
3. The method of target enhanced up-conversion imaging according to claim 2, wherein the signal light wavelength is 1550nm, and the pump light wavelength is 780nm; the working wavelength of the first phase type spatial light modulator is matched with the wavelength of the signal light, and the working wavelength of the second phase type spatial light modulator is matched with the wavelength of the pump light.
4. The method of claim 2 or 3, wherein the target information is image information for communication.
5. A target enhanced up-conversion imaging system, comprising:
the phase-type spatial light modulator comprises a first phase-type spatial light modulator, a second phase-type spatial light modulator, a nonlinear crystal, a first Fourier lens, a second Fourier lens, a third Fourier lens, a fourth Fourier lens, a fifth Fourier lens, a sixth Fourier lens, a seventh Fourier lens, a reflector and a detector;
the signal light is loaded with target information after passing through the first phase type spatial light modulator, is imaged by a first Fourier lens and a second Fourier lens, is transmitted by a first dichroic mirror and then is subjected to standard Fourier transform by a sixth Fourier lens to obtain signal light for entering the nonlinear crystal;
after passing through two 4f imaging systems consisting of a third Fourier lens, a fourth Fourier lens, a fifth Fourier lens and a sixth Fourier lens, pump light is incident to the nonlinear crystal;
and the pump light and the signal light generate a second-order nonlinear effect in the nonlinear crystal to obtain an up-conversion light field, the up-conversion light field is separated from the pump light and the signal light through a second dichroic mirror, and the separated up-conversion light field is subjected to space Fourier inverse transformation through a seventh Fourier lens to obtain a target light field after target enhancement so as to be received through a detector.
6. The target enhanced up-conversion imaging system of claim 5, wherein:
the wavelength of the signal light is 1550nm, and the wavelength of the pump light is 780nm;
the working wavelength of the first phase type spatial light modulator is matched with the wavelength of the signal light, and the working wavelength of the second phase type spatial light modulator is matched with the wavelength of the pump light.
7. The target enhanced up-conversion imaging system of claim 5 or 6, wherein the target information is image information for communication.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211542509.XA CN115793348B (en) | 2022-12-03 | 2022-12-03 | Target enhanced up-conversion imaging method and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211542509.XA CN115793348B (en) | 2022-12-03 | 2022-12-03 | Target enhanced up-conversion imaging method and system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115793348A true CN115793348A (en) | 2023-03-14 |
| CN115793348B CN115793348B (en) | 2023-07-14 |
Family
ID=85445273
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211542509.XA Active CN115793348B (en) | 2022-12-03 | 2022-12-03 | Target enhanced up-conversion imaging method and system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115793348B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111650800A (en) * | 2020-05-13 | 2020-09-11 | 哈尔滨理工大学 | Brillouin signal space frequency spectrum regulation and control noise filtering method and device |
| US10824049B1 (en) * | 2017-10-06 | 2020-11-03 | Hrl Laboratories, Llc | Optical-frequency up-converting spectrometric imager |
| CN213069366U (en) * | 2020-06-17 | 2021-04-27 | 青岛鲲腾量子应用技术有限公司 | Up-conversion imaging processing device based on field of view and edge enhancement |
| US20210389644A1 (en) * | 2020-09-15 | 2021-12-16 | Shan Dong University | Parametric Light Generation Method and Its Application |
| CN114486788A (en) * | 2021-09-29 | 2022-05-13 | 华东师范大学重庆研究院 | Large-view-field ultra-sensitive intermediate infrared frequency up-conversion imaging technology and device |
-
2022
- 2022-12-03 CN CN202211542509.XA patent/CN115793348B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10824049B1 (en) * | 2017-10-06 | 2020-11-03 | Hrl Laboratories, Llc | Optical-frequency up-converting spectrometric imager |
| CN111650800A (en) * | 2020-05-13 | 2020-09-11 | 哈尔滨理工大学 | Brillouin signal space frequency spectrum regulation and control noise filtering method and device |
| CN213069366U (en) * | 2020-06-17 | 2021-04-27 | 青岛鲲腾量子应用技术有限公司 | Up-conversion imaging processing device based on field of view and edge enhancement |
| US20210389644A1 (en) * | 2020-09-15 | 2021-12-16 | Shan Dong University | Parametric Light Generation Method and Its Application |
| CN114486788A (en) * | 2021-09-29 | 2022-05-13 | 华东师范大学重庆研究院 | Large-view-field ultra-sensitive intermediate infrared frequency up-conversion imaging technology and device |
Non-Patent Citations (1)
| Title |
|---|
| HAO-RAN YANG 等: "Parametric upconversion of Ince–Gaussian modes", 《OPTICS LETTERS》, vol. 45, no. 11, pages 3034 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115793348B (en) | 2023-07-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Bradburn et al. | Realizations of focus invariance in optical–digital systems with wave-front coding | |
| Lu et al. | Implementation of a non-zero-order joint-transform correlator by use of phase-shifting techniques | |
| US5111515A (en) | Image deconvolution by a logarithmic exponential nonlinear joint transform process | |
| US20080151391A1 (en) | Imaging system and method for providing extended depth of focus, range extraction and super resolved imaging | |
| Rai et al. | Depth-of-field engineering in coded aperture imaging | |
| CN111780681B (en) | Vector nonlinear optical spatial filter | |
| US5943170A (en) | Adaptive or a priori filtering for detection of signals corrupted by noise | |
| CN108227187A (en) | A kind of method and system of expansion optical Depth of field | |
| Hoffmire et al. | Deep learning for anisoplanatic optical turbulence mitigation in long-range imaging | |
| CN115793348B (en) | Target enhanced up-conversion imaging method and system | |
| Hardie et al. | Application of tilt correlation statistics to anisoplanatic optical turbulence modeling and mitigation | |
| Wei et al. | Low-cost and simple optical system based on wavefront coding and deep learning | |
| CN116485829A (en) | Image edge detection method and device based on complex amplitude filtering topological space differential operation and complex amplitude modulation module | |
| Javidi et al. | Image deconvolution by nonlinear signal processing | |
| Ishikawa et al. | Deep sound-field denoiser: optically-measured sound-field denoising using deep neural network | |
| JPS63127223A (en) | Image processor | |
| Xu et al. | Implementing the edge enhancement with vortex filter in both linear and nonlinear optics | |
| Sakurai et al. | Phase Distortion Suppression by Deep Neural-Network-Based Single-Pixel Imaging | |
| Considine et al. | Optical image enhancement and image restoration | |
| US5594586A (en) | Photorefractive limiting quadratic processor | |
| Zhao et al. | Edge enhancement of phase objects through complex media by using transmission-matrix-based spiral phase contrast imaging | |
| Juvells et al. | Implementation of real filters in a joint transform correlator using a positive-only display | |
| Arrasmith et al. | Novel wavelength diversity technique for high-speed atmospheric turbulence compensation | |
| Liu et al. | Meta-lenses for differential imaging based on weak measurement | |
| Weeks et al. | Nonlinear image transformations implemented with spatial light modulators |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |