Method and device for predicting passive laser emission effect

Abstract

The invention relates to the technical field of image processing, in particular to a passive laser emission effect prediction method and device, and the method comprises the steps: obtaining an influence distribution field of turbulence on an image according to an obtained actual far-field image; transforming a light spot far-field distribution image output by the laser according to the influence distribution field to obtain a laser distribution function; and determining the light intensity distribution at any position of the target by using the total laser power and the laser distribution function at the target position. The method for predicting the passive laser emission effect aims at solving the problem that the real-time prediction of the atmospheric visibility condition is poor.

Description

Technical Field

[0001] The present invention relates to the technical field of image processing, and in particular to a method and device for predicting passive laser emission effects. Background Art

[0002] At present, the image-based atmospheric visibility detection method has been widely used in the field of road video monitoring, such as "Visibility detection method based on road condition monitoring video (CN101382497B)", but for systems that actively emit lasers, such as laser countermeasures, laser photometry, and laser communication, the typical method is still to use discrete visibility and atmospheric turbulence test equipment to abstract the current atmospheric conditions into a few parameters such as visibility and atmospheric turbulence, and calculate the effect through experience or formulas, such as "A method for converting the equivalent action distance of photoelectric sensors under different atmospheric visibilities (CN110926515B)". This method not only requires more equipment support, but the calculation process usually takes more than a few minutes, at which time the atmospheric conditions may have partially changed, and cannot meet the real-time requirements of the above fields.

[0003] Therefore, the inventor provides a method and device for predicting the effect of passive laser emission. Summary of the invention

[0004] (1) Technical issues to be solved

[0005] The embodiments of the present invention provide a method and device for predicting the effect of passive laser emission, which solve the technical problem of poor real-time prediction of atmospheric visibility conditions.

[0006] (2) Technical solution

[0007] A first aspect of the present invention provides a method for predicting the effect of passive laser emission, which is applied to a transmitting and receiving common optical path optical system, and the method comprises the following steps:

[0008] Based on the actual far-field image obtained, the distribution field of the influence of turbulence on the image is obtained;

[0009] According to the impact distribution field, the far-field distribution image of the light spot output by the laser is transformed to obtain a laser distribution function;

[0010] The light intensity distribution at any position of the target is determined by using the total laser power at the target position and the laser distribution function.

[0011] Furthermore, obtaining the distribution field of the influence of turbulence on the image based on the actual far-field image obtained specifically includes the following steps:

[0012] Acquiring an actual far-field image distorted by turbulence, wherein the actual far-field image changes in real time with changes in atmospheric turbulence;

[0013] The distortion of the actual far-field image is calculated by an image de-turbulence algorithm, thereby obtaining an image without turbulence, and the influence distribution field is obtained by distorting the image.

[0014] Furthermore, the influence distribution field of turbulence on the image is obtained based on the actual far-field image obtained, specifically:

[0015] The impact distribution field is obtained from the actual far-field image distorted by turbulence through an image restoration model based on an unsupervised neural network.

[0016] Furthermore, the far-field distribution image of the light spot output by the laser is transformed according to the impact distribution field to obtain the laser distribution function, which is specifically:

[0017] The light spot far-field distribution image is transformed according to the impact distribution field to obtain the laser distribution function.

[0018] Furthermore, the total laser power at the target position is positively correlated with the total power at the laser outlet and the transmission distance, and the total laser power at the target position is negatively correlated with the atmospheric extinction coefficient.

[0019] Furthermore, the expression of the light intensity distribution I(x, y) at any position of the target is:

[0020] I(x,y)=P0·exp[-σ(λ)L]·I N (x,y);

[0021] Where P0 is the total power at the laser outlet, L is the laser transmission distance, σ(λ) is the atmospheric extinction coefficient at wavelength λ, exp(x) is the natural exponential function, and I N (x, y) is the laser distribution function.

[0022] Furthermore, the determination of the atmospheric extinction coefficient specifically includes the following steps:

[0023] The mean shift is used to accurately segment the sky area, and the local entropy is used to estimate the atmospheric light intensity value in the sky area;

[0024] The initial transmittance of the image is obtained using the dark color prior, and bilateral filtering is used for optimization to obtain the atmospheric extinction coefficient.

[0025] Furthermore, the laser distribution function I N (x, y) satisfies the following conditions:

[0026] ∫∫I N (x,y)dxdy=1.

[0027] A second aspect of the present invention provides a prediction device for a passive laser emission effect, the prediction device comprising:

[0028] An image acquisition unit, used to obtain the distribution field of the influence of turbulence on the image according to the acquired actual far-field image;

[0029] An image transformation unit, used for transforming the far-field distribution image of the light spot output by the laser according to the impact distribution field to obtain a laser distribution function;

[0030] The light intensity calculation unit is used to determine the light intensity distribution at any position of the target by using the total laser power at the target position and the laser distribution function.

[0031] Furthermore, the image acquisition unit is specifically used for:

[0032] Acquiring an actual far-field image distorted by turbulence, wherein the actual far-field image changes in real time with changes in atmospheric turbulence;

[0033] The distortion of the actual far-field image is calculated by an image de-turbulence algorithm, thereby obtaining an image without turbulence, and the influence distribution field is obtained by distorting the image.

[0034] (3) Beneficial effects

[0035] In summary, the present invention can characterize the actual power distribution by obtaining the laser distribution function at the target position, and does not need to add visibility, atmospheric turbulence testing equipment and other devices. The calculation is simple and the accuracy is higher, thereby achieving quasi-real-time strike effect evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments of the present invention are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 It is a flow chart of a method for predicting a passive laser emission effect provided by an embodiment of the present invention;

[0038] Figure 2 It is a structural schematic diagram of a transmitting and receiving common optical path optical system;

[0039] Figure 3 It is a schematic diagram of the structure of a passive laser emission effect prediction device provided by an embodiment of the present invention.

[0040] In the figure:

[0041] 1-Laser; 2-Camera; 3-Dichroic mirror; 4-Optical system; 5-Atmospheric transmission; 6-Far-field target; 7-Light spot; 8-Laser; 9-Visible light. DETAILED DESCRIPTION

[0042] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention, that is, the present invention is not limited to the described embodiments, and covers any modification, replacement and improvement of parts, components and connection modes without departing from the spirit of the present invention.

[0043] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0044] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the products of the present invention are conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0045] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting" and "installation" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] Figure 1 is a flow chart of a method for predicting a passive laser emission effect provided by an embodiment of the present invention, see Figure 1 , the method may include the following steps:

[0047] S100 , obtaining a distribution field of influence of turbulence on the image according to the acquired actual far-field image.

[0048] Specifically, step S100 includes the following steps:

[0049] S101, acquiring an actual far-field image distorted by turbulence, wherein the actual far-field image changes in real time with changes in atmospheric turbulence;

[0050] S102, calculating the distortion of the actual far-field image by using an image de-turbulence algorithm, thereby obtaining an image without turbulence, and obtaining an impact distribution field by using the distorted image.

[0051] After the actual far-field object is transmitted through the atmosphere, a set of images distorted by turbulence is formed on the detector. Since the image set can change in real time with the atmospheric turbulence, the distortion of the current image can be calculated by the Gunner-Farneback dense optical flow method, thereby obtaining an image without turbulence, and obtaining the distribution of the influence of turbulence on the image through the distorted image. In addition, an image restoration model based on an unsupervised neural network, including a grid deformer that generates an estimated distortion field and an image generator that estimates a turbulence-free image, can be used to obtain both a turbulence-free image and the distribution of the influence of turbulence on the image directly from a single or multiple images distorted by turbulence.

[0052] S200, transforming the far-field distribution image of the light spot output by the laser according to the impact distribution field to obtain a laser distribution function.

[0053] Specifically, in an ideal situation without turbulence, the imaging of the far-field distribution of the spot output by the laser on the camera can be obtained a priori through the optical system parameters, similar to the calculation method of the diffraction divergence angle of the light beam in the traditional method. By transforming this distribution according to the field affected by turbulence on the image, the far-field distribution of the laser in the case of turbulence can be obtained, and the laser distribution function can be obtained.

[0054] Among them, the laser distribution function I N (x, y) satisfies the condition: ∫∫I N (x,y)dxdy=1.

[0055] S300, using the total laser power and the laser distribution function at the target position, determine the light intensity distribution at any position at the target.

[0056] Specifically, the total laser power at the target position is positively correlated with the total power at the laser outlet and the transmission distance, and the total laser power at the target position is negatively correlated with the atmospheric extinction coefficient.

[0057] As an optional implementation, the expression of the light intensity distribution I(x, y) at any position of the target is: I(x, y) = P0·exp[-σ(λ)L]·I N (x,y);

[0058] Where P0 is the total power at the laser outlet, L is the laser transmission distance, σ(λ) is the atmospheric extinction coefficient at wavelength λ, exp(x) is the natural exponential function, and I N (x, y) is the laser distribution function.

[0059] Furthermore, the determination of the atmospheric extinction coefficient specifically includes the following steps:

[0060] The mean shift is used to accurately segment the sky area, and the local entropy is used to estimate the atmospheric light intensity value in the sky area;

[0061] The initial transmittance of the image is obtained using the dark color prior, and bilateral filtering is used for optimization to obtain the atmospheric extinction coefficient.

[0062] This prediction method can be applied to Figure 2 In the optical system for transmitting and receiving in a common optical path, the optical system 4 (which can be a transmission or reflection optical system) can not only converge the visible light 9 into the camera 2, so that the camera 2 can image the far-field target 6, but also project the laser light 8 output by the laser 1 to the target position to form a light spot 7. The dichroic mirror 3 has a high reflectivity for the wavelength of the laser light 8, and projects the wavelength band of other visible light 9, thereby realizing the design of transmitting and receiving in a common optical path.

[0063] Since the visible light 9 and the laser 8 are transmitted through the long-distance atmosphere 5 together, the attenuation and distortion of the image received by the camera 2 caused by the atmospheric transmission 5 can be used to characterize the attenuation and distortion of the light spot 7 caused by the atmospheric transmission 5 .

[0064] Figure 3 is a schematic diagram of a passive laser emission effect prediction device provided by an embodiment of the present invention, see Figure 3 , the prediction device may include:

[0065] An image acquisition unit 301 is used to obtain a distribution field of the influence of turbulence on the image according to the acquired actual far-field image;

[0066] An image transformation unit 302 is used to transform the far-field distribution image of the light spot output by the laser according to the impact distribution field to obtain a laser distribution function;

[0067] The light intensity calculation unit 303 is used to determine the light intensity distribution at any position of the target by using the total laser power and the laser distribution function at the target position.

[0068] As an optional implementation manner, the image acquisition unit 303 is specifically used for:

[0069] Acquire the actual far-field image distorted by turbulence, and the actual far-field image changes in real time with the change of atmospheric turbulence;

[0070] The distortion of the actual far-field image is calculated by the image de-turbulence algorithm to obtain an image without turbulence, and the impact distribution field is obtained through the distorted image.

[0071] It should be clear that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. In addition, for the sake of brevity, a detailed description of known methods and technologies is omitted here.

[0072] The above are only embodiments of the present application and are not limited to the present application. For those skilled in the art, the present application may have various changes and variations without departing from the scope of the present invention. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for predicting the effect of passive laser emission, characterized in that: Applied to a common optical path optical system for transmitting and receiving, the method comprises the following steps: Based on the actual far-field image obtained, the distribution field of the influence of turbulence on the image is obtained; According to the impact distribution field, the far-field distribution image of the light spot output by the laser is transformed to obtain a laser distribution function; The light intensity distribution at any position of the target is determined by using the total laser power at the target position and the laser distribution function.

2. The method for predicting the passive laser emission effect according to claim 1, characterized in that: The method of obtaining the influence distribution field of turbulence on the image based on the actual far-field image obtained specifically includes the following steps: Acquiring an actual far-field image distorted by turbulence, wherein the actual far-field image changes in real time with changes in atmospheric turbulence; The distortion of the actual far-field image is calculated by an image de-turbulence algorithm, thereby obtaining an image without turbulence, and the influence distribution field is obtained by distorting the image.

3. The method for predicting the passive laser emission effect according to claim 1, characterized in that: The influence distribution field of turbulence on the image is obtained based on the actual far-field image obtained, specifically: The impact distribution field is obtained from the actual far-field image distorted by turbulence through an image restoration model based on an unsupervised neural network.

4. The method for predicting the effect of passive laser emission according to claim 1, characterized in that: The far-field distribution image of the light spot output by the laser is transformed according to the impact distribution field to obtain the laser distribution function, which is specifically: The light spot far-field distribution image is transformed according to the impact distribution field to obtain the laser distribution function.

5. The method for predicting the passive laser emission effect according to claim 1, characterized in that: The total laser power at the target position is positively correlated with the total power at the laser outlet and the transmission distance, and the total laser power at the target position is negatively correlated with the atmospheric extinction coefficient.

6. The method for predicting the passive laser emission effect according to claim 5, characterized in that: The expression of the light intensity distribution I(x, y) at any position of the target is: I(x,y)=P0·exp[-σ(λ)L]·I N (x,y); Where P0 is the total power at the laser outlet, L is the laser transmission distance, σ(λ) is the atmospheric extinction coefficient at wavelength λ, exp(x) is the natural exponential function, and I N (x, y) is the laser distribution function.

7. The method for predicting the passive laser emission effect according to claim 5, characterized in that: The determination of the atmospheric extinction coefficient specifically includes the following steps: The mean shift is used to accurately segment the sky area, and the local entropy is used to estimate the atmospheric light intensity value in the sky area; The initial transmittance of the image is obtained using the dark color prior, and bilateral filtering is used for optimization to obtain the atmospheric extinction coefficient.

8. The method for predicting the passive laser emission effect according to claim 1, characterized in that: The laser distribution function I N (x, y) satisfies the following conditions: ∫∫I N (x,y)dxdy=1.

9. A device for predicting the effect of passive laser emission, characterized in that: include: An image acquisition unit, used to obtain the distribution field of the influence of turbulence on the image according to the acquired actual far-field image; An image transformation unit, used for transforming the far-field distribution image of the light spot output by the laser according to the impact distribution field to obtain a laser distribution function; The light intensity calculation unit is used to determine the light intensity distribution at any position of the target by using the total laser power at the target position and the laser distribution function.

10. The passive laser emission effect prediction device according to claim 9, characterized in that: The image acquisition unit is specifically used for: Acquiring an actual far-field image distorted by turbulence, wherein the actual far-field image changes in real time with changes in atmospheric turbulence; The distortion of the actual far-field image is calculated by an image de-turbulence algorithm, thereby obtaining an image without turbulence, and the influence distribution field is obtained by distorting the image.

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