Method for express determination of range and probability of recognition of objects during aerial reconnaissance

Abstract

FIELD: technical physics.SUBSTANCE: invention can be used in flight (full-scale) tests of aviation optical-electronic systems and their qualimetry based on the analysis and processing of images of ground-based aerial reconnaissance objects and line targets of the visible range. The method consists of placing on the terrain line targets and ground-based aerial reconnaissance objects equipped with a radio frequency identification tag, measuring the range Dm to ground-based aerial reconnaissance objects when performing aerial photography with an optical-electronic system with a priori specified values of the altitude and flight course of the aircraft, determining the contrast of ground objects by measuring on the ground the brightness of the ground object and the background on which the ground object is located, during aerial photography by an optoelectronic system, selecting at least 20 digital aerial photographs with images of ground objects, analysing and decoding the obtained images of aerial reconnaissance objects at an automated workstation of image visualization tools, determining the probability of recognizing ground objects presented for recognition, calculating an estimate of the probability of recognizing typical objects as the arithmetic mean of the values of the estimates, the average obtained by all decoders for all decoded images.EFFECT: expansion of the functional capabilities for determining the probability of recognizing ground objects of aerial reconnaissance by an optoelectronic system of manned and unmanned aerial vehicles for processing information, ensuring a reduction in the number of full-scale experiments.1 cl, 1 dwg

Description

[0001] The invention relates to technical physics and can be used in conducting flight (full-scale) tests of aviation optical-electronic systems and their qualimetry based on the analysis and processing of images of ground-based aerial reconnaissance objects and line targets of the visible range.

[0002] A known method for detecting optical and optoelectronic devices (RU Patent No. 2133485) involves probing the ground with scanned pulsed laser radiation, receiving optical signals from a specified range, converting the received signals into a video signal, threshold selection of the received signals, probing the spatial volume at a fixed frequency, encoding the emitted sequence of laser pulses, and detecting an alarm signal. The disadvantages of this method include the low probability of correctly detecting optical devices with simple threshold processing (selection) of the received signal at a fixed wavelength from the monitored spatial volume, as well as the inability to determine the belonging of the detected optical device to a specific class of optoelectronic devices, i.e., to recognize the detected objects.

[0003] A known method for detecting optical and optoelectronic surveillance equipment and a device for implementing it (patent RU 2524450) involves receiving natural background radiation signals, measuring the spectral distribution of the radiation, and determining the ratio between the intensities of its spectral components at three selected wavelengths. These values ​​are used to generate a spectral profile of the retroreflectivity index, which is used to detect and recognize optical and optoelectronic surveillance equipment. The technical result of this method is to increase the probability of detecting and recognizing optical and optoelectronic devices and surveillance equipment, and to determine their membership in known classes of optoelectronic devices. The disadvantages of this method include the large number of full-scale experiments required, as well as the length and complexity of conducting full-scale experiments.

[0004] The closest analogue known from the prior art is a method for expressly determining the probability of recognizing objects when conducting aerial reconnaissance (patent for invention RU 2836102), which consists of placing line targets and ground-based aerial reconnaissance objects equipped with a radio frequency identification tag on the terrain, aerial photography with an optoelectronic system of line targets and ground-based aerial reconnaissance objects at a priori specified values ​​of the altitude and flight course of the aircraft, determining the actual modulation contrast of the line targets and the contrast of ground objects, decoding the images of the line targets displayed on the automated workstation of the visualization equipment by at least three decoder operators, based on the results of which recognized groups of lines are determined, in which all lines are observed separately along their entire length and the smallest group of lines in width,In a system in which all lines are distinguished separately along their entire length and there is a visual perception of the difference in gray level on the screen between each light stripe and its adjacent dark stripes along their entire length, the recognition probability of ground aerial reconnaissance targets is determined using the established experimental relationship between the recognition probability and the linear resolution of the terrain. A disadvantage of this method is the failure to take into account the recognition range using the established experimental relationship with the recognition probability.

[0005] The technical objective of the claimed invention is to develop methods for determining the probability of recognizing ground-based aerial reconnaissance objects by simplifying the process of processing the information obtained without performing additional full-scale experiments.

[0006] The solution to the technical problem is achieved by placing typical aerial reconnaissance objects on the ground along and across the flight path of an aircraft equipped with an optical-electronic system, then, with a priori specified values ​​for the altitude and flight course of the aircraft, aerial photography is carried out of areas of the terrain with the placed ground-based aerial reconnaissance objects, while simultaneously measuring the range during the aerial photography. mto ground-based aerial reconnaissance objects, process the images, calculate the ranges and probabilities of recognition of ground-based aerial reconnaissance objects by the optical-electronic system of the aircraft as the arithmetic mean of the values ​​of range estimates and the probability of recognition of a typical aerial reconnaissance object obtained by all decoder operators for all images, determining the actual contrast of a typical aerial reconnaissance object based on the results of on-the-ground measurements of the brightness of the object and the background on which the ground object is located, at the time of aerial photography by the optical-electronic system, in accordance with the expression ,K n =(K об -K ф ) / TO об , whereK об andK ф – results of measurements of the brightness of the object and background at the time of aerial photography, cd / m 2 , calculate the probabilities of recognition of ground objects P = n1 / n2, where n1 is the number of correctly recognized objects, n2 is the number of objects presented for recognition, the arithmetic mean value of the probability of recognizing typical objects is calculated, obtained by all decoders for all decoded images , determining the probability of recognizing ground objects up to the classification levels of ground objects: “type”, “class”, “subclass” and “type” depending on the obtained range , where D m – the obtained object recognition range based on the results of field experiments (aerial photography), D m 0 – the worst value of the object recognition range, D p – theoretical (calculated) value of the object recognition range, m L – mathematical expectation, σ– standard deviation.

[0007] The technical result achieved by the set of features of the claimed invention consists in expanding the functional capabilities of determining the probability of recognizing ground-based aerial reconnaissance objects by an optical-electronic information processing system of manned and unmanned aerial vehicles, ensuring a reduction in the number of full-scale experiments.

[0008] The essence of the invention lies in the following sequence of operations.

[0009] 1. Set up ground-based aerial reconnaissance facilities on the ground.

[0010] 2. Conduct aerial photography of the terrain with ground-based aerial reconnaissance targets using an optoelectronic (aerial photography) system at specified altitude and flight path values ​​of the aircraft (manned or unmanned). Simultaneously, during the aerial photography, the range is measured. m to ground-based aerial reconnaissance targets.

[0011] 3. The aircraft flight course is selected so that ground aerial reconnaissance objects are within ±10° of the lines perpendicular and parallel to the flight direction, respectively.

[0012] The lateral distance of the aircraft's path from ground objects located on the earth's surface is selected in such a way that the images of ground objects fall in the center of the aerial photograph.

[0013] Flights are conducted in the absence of clouds and fog in the atmospheric layer between the aircraft flight path and the earth's surface on which ground objects are located.

[0014] 4. Determine the contrast of ground objects by measuring the brightness of the ground object and the background on which the ground object is located on the ground during aerial photography using an optical-electronic (aerial photographic) system. The contrast of a ground object is determined by the formula

[0015] ,K n =(K об -K ф ) / TO об ,

[0016] whereKоб andK ф – results of measurements of the brightness of the object and background at the time of aerial photography, cd / m 2 Measurement of brightness and ground objects is carried out simultaneously with aerial photography during aircraft flights over ground objects, at no less than five measurement points.

[0017] 5. To calculate the recognition range estimate and the recognition probability of aerial reconnaissance objects of the optical-electronic system, it is necessary to obtain at least 20 images of aerial reconnaissance objects.

[0018] 6. Perform analysis of the received images by at least three decoder operators.

[0019] 7. Conduct an analysis of the obtained images of aerial reconnaissance objects on the automated workstation of image visualization equipment.

[0020] 8. Select digital aerial photographs obtained with aircraft angular oscillations not exceeding permissible values, with ground reconnaissance targets located at the center of the aerial photograph or at distances no greater than 20% of the transverse and longitudinal dimensions of the aerial photograph, respectively, along the horizontal and vertical sides. At least 20 digital aerial photographs containing ground targets will be selected.

[0021] 9. Conduct deciphering of selected images of aerial reconnaissance objects.

[0022] 10. Determine the probabilities of ground object recognition. The recognition probability P is defined as the frequency of correct object recognition:

[0023] P=n1 / n2,

[0024] where n1 is the number of correctly recognized objects, n2 is the number of objects presented for recognition.

[0025] 11. The final probability of recognizing typical objects is to be taken as the arithmetic mean value obtained by all decoders for all decoded images:

[0026] ,

[0027] where m is the total number of decryption results.

[0028] 12. Determine the relationship between the probability and range of object recognition. Assuming that random variables obey the normal Gaussian distribution, the recognition probability can be determined from an expression whose parameters are D p andD m determined by calculation and based on the results of field experiments (aerial photography):

[0029] , where D m – the obtained object recognition range based on the results of field experiments (aerial photography), D m0 – the worst value of the object recognition range, D p – theoretical (calculated) value of the object recognition range, m L– mathematical expectation, σ– standard deviation.

[0030] 13. Based on the obtained dependencies, determine the probabilities of object recognition up to the ground object classification levels: “type”, “class”, “subclass” and “type”, depending on the required (specified) object recognition range, as illustrated by the figure.

[0031] The presence of radio frequency identification (RFID) tags on ground objects simplifies the search for the location of objects when planning the flight path of an aircraft.

[0032] The distinctive feature of the claimed method is that, when it is implemented, the values ​​of the probabilities of recognition of ground-based aerial reconnaissance objects are obtained according to a previously established experimental dependence of the value of the recognition probability on the recognition range, which simplifies the process of obtaining results, reduces the number of full-scale experiments, and does not require conducting additional full-scale flight experiments.

[0033] Table 1 presents the results of decoding the objects received by the OETS-LPC of the Orlan-30 UAV system with H=500 m and slant range D=1500 m. The OETS-LPC of the Orlan-30 UAV system with a flight altitude of H=500 m and slant range D=1500 m provides a recognition range of D=10.8…17.5 km. At this range, detection and recognition is ensured down to the "type" level: aircraft with a probability of 0.6…0.69, automotive vehicles with a probability of 0.57…0.65, motor vehicles with a probability of 0.71, and armored vehicles with a probability of 0.35. In this case, the "type" and "class" of objects are recognized confidently, but the "type" is not entirely possible to determine.

[0034] Table 1 – Results of deciphering objects obtained by the OESP-LPTs complex with the Orlan-30 UAV with H=500 m and slant range D=1500 m

[0035] Item No. Name of the object Background Contrast Kobjectbackground / Kobjectshadow Recognition probability Range, km view Class subclass type 1 Su-27 Concrete 0,46 / 0,64 1 1 0,98 0,67 17,5 2 Su-17 Soil with grass 0,28 / 0,49 1 1 0,9 0,69 16 3 MiG-31 Concrete 0,42 / 0,74 1 1 0,92 0,6 14 4 Gazelle car Concrete 0,43 / 0,84 1 1 0,95 0,65 14,7 5 Lada Granta car Concrete 0,35 / 0,69 1 1 0,83 0,57 12,1 6 MTZ tractor Soil with grass 0,52 / 0,84 1 1 0,82 0,71 12 7 Armored vehicles (Osa air defense missile system) Concrete 0,47 / 0,77 1 0,97 0,75 0,35 10,8 8 Ural 4320 car Soil with grass 0,36 / 0,75 1 1 0,88 0,63 12,6

[0036] Table 2 presents the results showing the effect of applying the proposed method

[0037] Table 2 – Comparison of the existing and declared methods for determining the probability of object recognition

[0038] Number of test flights to determine the probability of object recognition Existing Declared to the point of view 2 0 to class 2 0 to subclass 2 0 to type 2 2 Reliability of determining the probability of object recognition 95,0 % 93,6%

[0039] Analysis of the results presented in Table 2 shows that the effect of implementing the claimed method for determining the probability of object recognition:

[0040] reducing the number of test flights to evaluate the FPM of digital image processing equipment (according to the test program - 8 flights, 2 flights completed) while maintaining high reliability of test results (93.6%);

[0041] reducing the time for preparation, planning and conducting field experiments to 15 days.

[0042] The technical result achieved by the set of features of the claimed invention consists in expanding the functional capabilities of determining the probability of recognizing ground-based aerial reconnaissance objects by an optical-electronic information processing system of manned and unmanned aerial vehicles, ensuring a reduction in the number of full-scale experiments.

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