CN112484692B - Visual detection method and device for relative height of aircraft and cloud layer - Google Patents
Visual detection method and device for relative height of aircraft and cloud layer Download PDFInfo
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- CN112484692B CN112484692B CN202011228039.0A CN202011228039A CN112484692B CN 112484692 B CN112484692 B CN 112484692B CN 202011228039 A CN202011228039 A CN 202011228039A CN 112484692 B CN112484692 B CN 112484692B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C5/00—Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels
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Abstract
The invention provides a relative height visual detection method and device of an aircraft and a cloud layer, wherein the method comprises the following steps: acquiring an image shot by an imaging system on an aircraft servo frame; detecting the upper boundary and the lower boundary of a cloud layer in the image by using a cloud layer image detection algorithm; determining a horizontal position line in the image according to the pitch angle of the attitude of the aircraft and the pitch angle of the servo frame; and determining the relative height of the aircraft and the cloud layer according to the horizontal position line and the position relation between the upper boundary and the lower boundary of the cloud layer. According to the method and the device for visually detecting the relative height of the aircraft and the cloud layer, the relative height of the aircraft and the cloud layer can be detected by using the self-contained optical imaging system and the servo frame, and a detection basis is provided for the aircraft to actively avoid the cloud layer from shielding a target.
Description
Technical Field
The invention belongs to the technical field of vision measurement, and particularly relates to a method and a device for visually detecting the relative height of an aircraft and a cloud layer.
Background
In the field of vision measurement, a cloud base height detection technology is adopted, and the height of a cloud base relative to the ground can be measured.
However, when the aircraft flies, the relative height between the aircraft and the cloud layer cannot be directly and rapidly determined only according to the height of the cloud base relative to the ground, and the thickness of the cloud layer cannot be determined in the prior art, so that the judgment of the relative height between the aircraft and the cloud layer is influenced.
Disclosure of Invention
The purpose of the invention is as follows: the invention provides a method and a device for visually detecting the relative height of an aircraft and a cloud layer, which solve the problem that the relative height of the aircraft and the cloud layer cannot be quickly and accurately judged in the prior art.
The technical scheme of the invention is as follows:
the invention provides a relative height visual detection method of an aircraft and a cloud layer, which comprises the following steps:
acquiring an image shot by an imaging system on an aircraft servo frame;
detecting the upper boundary and the lower boundary of a cloud layer in the image by using a cloud layer image detection algorithm;
determining a horizontal position line in the image according to the pitch angle of the attitude of the aircraft and the pitch angle of the servo frame;
and determining the relative height of the aircraft and the cloud layer according to the horizontal position line and the position relation between the upper boundary and the lower boundary of the cloud layer.
Optionally, determining a horizontal position line in the image according to the pitch angle of the aircraft attitude and the pitch angle of the servo frame includes:
determining the number of pixels of deviation between a horizontal position line in the image and a central horizontal position line of the image according to the pitch angle of the attitude of the aircraft and the pitch angle of the servo frame;
when the number of the deviation pixels is positive, determining that the horizontal position line is positioned below a central horizontal position line, and the distance from the horizontal position line to the lower part of the central horizontal position line is the number of the deviation pixels;
and when the number of the deviation pixels is negative, determining that the horizontal position line is above the central horizontal position line, and the distance from the horizontal position line to the lower part of the central horizontal position line is the absolute value of the number of the deviation pixels.
Optionally, the number of offset pixels = (fsin θ)/(pixel × cos γ);
wherein theta is the sum of the pitch angle of the attitude of the aircraft and the pitch angle of the servo frame; f is the focal length of the optical imaging system, pixel is the pixel size of a detector in the optical imaging system, and gamma is the included angle between the central horizontal position line and the ground horizontal plane.
Optionally, the method further includes:
if the cloud layer is not detected in the image by using a cloud layer image detection algorithm, changing a course angle and/or a pitch angle of a servo frame of the imaging system to obtain a new image;
and determining the relative height of the aircraft and the cloud layer according to the new image.
Optionally, the method further includes:
and if the cloud layer is not detected in the images shot at all angles of the servo frame of the imaging system by using a cloud layer image detection algorithm and the total gray level change of each image is within a preset range, determining that the flying height of the aircraft is equivalent to the height of the cloud layer.
Optionally, the determining the relative height of the aircraft and the cloud layer according to the horizontal position line and the position relationship between the upper boundary and the lower boundary of the cloud layer includes:
when the horizontal position line is above the upper boundary of the cloud layer, determining that the flying height of the aircraft is higher than the height of the cloud layer;
when the horizontal position line is below the lower boundary of the cloud layer, determining that the flying height of the aircraft is lower than the height of the cloud layer;
when the horizontal position line is between the upper cloud boundary and the lower cloud boundary, determining that the flying height of the aircraft is equivalent to the cloud height.
The invention also provides a relative height visual detection device of the aircraft and the cloud layer, which comprises:
the image acquisition module is used for acquiring an image shot by an imaging system on the aircraft servo frame;
the boundary acquisition module is used for detecting the upper boundary and the lower boundary of a cloud layer in the image by using a cloud layer image detection algorithm;
the horizontal position line determining module is used for determining a horizontal position line in the image according to the pitching angle of the attitude of the aircraft and the pitching angle of the servo frame;
and the relative height determining module is used for determining the relative height of the aircraft and the cloud layer according to the horizontal position line and the position relation between the upper boundary and the lower boundary of the cloud layer.
Optionally, the horizontal position line determining module is specifically configured to:
determining the number of pixels of deviation between a horizontal position line in the image and a central horizontal position line of the image according to the pitch angle of the attitude of the aircraft and the pitch angle of the servo frame;
and determining a horizontal position line in the image according to the deviation pixel number and the central horizontal position line of the image.
The invention has the advantages that:
the invention provides a relative height visual detection method and device of an aircraft and a cloud layer, which can detect the relative height of the aircraft and the cloud layer by using an optical imaging system and a servo frame, and provide a detection basis for the aircraft to actively avoid the cloud layer from shielding a target.
Drawings
FIG. 1 is a schematic flow chart of a relative altitude visual inspection method for an aircraft and a cloud layer provided by the invention;
FIG. 2 is a schematic diagram of the sum of the horizontal position line and the pitch angle in the image provided by the present invention;
fig. 3 is a schematic diagram of the detection of the relative heights of the aircraft and the cloud layer provided by the invention.
Detailed Description
The present invention is described in further detail below with reference to the attached drawings.
Fig. 1 is a schematic flow chart of a method for visually inspecting the relative altitude of an aircraft and a cloud layer provided by the present invention, and as shown in fig. 1, the method for visually inspecting the relative altitude of an aircraft and a cloud layer provided by the present invention includes the following steps:
s1, mounting a servo frame on an aircraft, mounting an optical imaging system with a focal length f on the servo frame, and enabling the sum of a pitch angle of an aircraft attitude and a pitch angle of the servo frame to be 0 degree when an optical axis of the optical system is in a horizontal state; marking a central horizontal position line in the image; the center-horizontal position line passes through the image center point, see fig. 2.
S2, flying the aircraft, and clearly imaging in real time by the optical imaging system;
it will be appreciated that both the pitch angle of the attitude of the aircraft and the pitch angle of the servo frame may change during flight.
And S3, searching a cloud layer in an imaging image of the optical imaging system, and detecting the upper boundary and the lower boundary of the cloud layer.
S4, marking a horizontal position line in an image imaged by the optical imaging system, wherein the relation between the pixel number of the position line moving relative to the central horizontal position line and the sum theta of the pitch angles is (fsin theta)/(pixel multiplied by cos gamma) pixels;
wherein theta is the sum of the pitch angle of the attitude of the aircraft and the pitch angle of the servo frame; f is the focal length of the optical imaging system, pixel is the pixel size of a detector in the optical imaging system, and gamma is the included angle between the central horizontal position line and the ground horizontal plane.
When the number of the deviation pixels is positive, determining that the horizontal position line is positioned below a central horizontal position line, and the distance from the horizontal position line to the lower part of the central horizontal position line is the number of the deviation pixels;
and when the number of the deviation pixels is negative, determining that the horizontal position line is above the central horizontal position line, and the distance from the horizontal position line to the lower part of the central horizontal position line is the absolute value of the number of the deviation pixels.
And S5, determining the relative height according to the horizontal position line and the upper boundary and the lower boundary of the cloud layer.
For example, referring to fig. 3, when the horizontal position line is above the upper boundary of the cloud layer, the aircraft flies above the cloud layer, and the flying height of the aircraft is higher than the cloud layer height;
when the horizontal position line is below the lower boundary of the cloud layer, the aircraft flies below the cloud layer, and the flying height of the aircraft is lower than the height of the cloud layer;
when the horizontal position line is between the upper boundary and the lower boundary of the cloud layer, the aircraft flies in the height range of the cloud layer, and the flying height of the aircraft is equivalent to the height of the cloud layer.
Optionally, when the cloud layer is not searched in S3, the pitch frame angle and the heading frame angle of the servo frame are changed to search for the cloud layer around the aircraft. It can be understood that the cloud layer cannot be searched, the total gray level change of the image in each searching direction is not obvious, and the gray level distribution of the image is relatively uniform, which indicates that the aircraft flies in the cloud layer at the moment, and the flying height of the aircraft is equivalent to the height of the cloud layer.
Optionally, the method for obtaining the image captured by the imaging system on the servo frame of the aircraft may be simplified by removing the servo frame to fixedly mount the imaging system on the aircraft, at this time, the pitch angle of the servo frame is replaced by the fixedly mounted pitch angle, and the θ is the sum of the pitch angle of the attitude of the aircraft and the fixedly mounted pitch angle.
Finally, it should be noted that the above examples are only illustrative of the implementation of the present invention and are not limiting. Although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical proposal described in the embodiments can be modified, or some technical features can be equally replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the present invention, and are intended to be included within the scope of the appended claims.
Claims (6)
1. A relative height visual detection method of an aircraft and a cloud layer is characterized by comprising the following steps:
acquiring an image shot by an imaging system on an aircraft servo frame;
detecting the upper boundary and the lower boundary of a cloud layer in the image by using a cloud layer image detection algorithm;
determining a horizontal position line in the image according to the pitch angle of the attitude of the aircraft and the pitch angle of the servo frame;
determining the relative height of the aircraft and the cloud layer according to the horizontal position line and the position relation between the upper boundary and the lower boundary of the cloud layer;
determining a horizontal position line in the image according to the pitch angle of the aircraft attitude and the pitch angle of the servo frame, comprising:
determining the number of pixels of deviation between a horizontal position line in the image and a central horizontal position line of the image according to the pitch angle of the attitude of the aircraft and the pitch angle of the servo frame;
when the number of the deviation pixels is positive, determining that the horizontal position line is positioned below a central horizontal position line, and the distance from the horizontal position line to the lower part of the central horizontal position line is the number of the deviation pixels;
when the number of the deviation pixels is negative, determining that the horizontal position line is above the central horizontal position line, and the distance from the horizontal position line to the lower part of the central horizontal position line is the absolute value of the number of the deviation pixels;
the center-horizontal position line is a horizontal position line passing through the center point of the image.
2. The method according to claim 1, characterized in that the number of offset pixels = (fsin θ)/(pixel);
wherein theta is the sum of the pitch angle of the attitude of the aircraft and the pitch angle of the servo frame; f is the focal length of an optical imaging system on an aircraft servo frame, and pixel is the pixel size of a detector in the optical imaging system.
3. The method of claim 1, further comprising:
if the cloud layer is not detected in the image by using a cloud layer image detection algorithm, changing a course angle and/or a pitch angle of a servo frame of the imaging system to obtain a new image;
and determining the relative height of the aircraft and the cloud layer according to the new image.
4. The method of claim 3, further comprising:
and if the cloud layer is not detected in the images shot at all angles of the servo frame of the imaging system by using a cloud layer image detection algorithm and the total gray level change of each image is within a preset range, determining that the flying height of the aircraft is equivalent to the height of the cloud layer.
5. The method of claim 1, wherein determining the relative altitude of the aircraft and the cloud layer according to the position relationship between the horizontal position line and the upper and lower boundaries of the cloud layer comprises:
when the horizontal position line is above the upper boundary of the cloud layer, determining that the flying height of the aircraft is higher than the height of the cloud layer;
when the horizontal position line is below the lower boundary of the cloud layer, determining that the flying height of the aircraft is lower than the height of the cloud layer;
when the horizontal position line is between the upper cloud boundary and the lower cloud boundary, determining that the flying height of the aircraft is equivalent to the cloud height.
6. A relative altitude visual inspection device of aircraft and cloud cover, characterized by includes:
the image acquisition module is used for acquiring an image shot by an imaging system on the aircraft servo frame;
the boundary acquisition module is used for detecting the upper boundary and the lower boundary of a cloud layer in the image by using a cloud layer image detection algorithm;
the horizontal position line determining module is used for determining a horizontal position line in the image according to the pitching angle of the attitude of the aircraft and the pitching angle of the servo frame;
the relative height determining module is used for determining the relative height of the aircraft and the cloud layer according to the horizontal position line and the position relation between the upper boundary and the lower boundary of the cloud layer; the horizontal position line determining module is specifically configured to:
determining the number of pixels of deviation between a horizontal position line in the image and a central horizontal position line of the image according to the pitch angle of the attitude of the aircraft and the pitch angle of the servo frame;
when the number of the deviation pixels is positive, determining that the horizontal position line is positioned below a central horizontal position line, and the distance from the horizontal position line to the lower part of the central horizontal position line is the number of the deviation pixels;
when the number of the deviation pixels is negative, determining that the horizontal position line is above the central horizontal position line, and the distance from the horizontal position line to the lower part of the central horizontal position line is the absolute value of the number of the deviation pixels;
the center horizontal position line is a horizontal position line passing through the center point of the image.
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