A ground marker for hyperspectral aerial photography

Abstract

The main problem that the present invention solves is how to make ground signs clearly imaged in all bands of hyperspectral aerial photography. A ground sign for hyperspectral aerial photography is characterized by comprising a light source, a scattering lens, and a shell, wherein the scattering lens is in the shape of an elongated strip, the light source comprises a visible light source and a near-infrared light source, the light source is located directly below the scattering lens, the width of the light source is smaller than the length of the scattering lens, and the light emitted by the light source passes through the scattering lens and then diverges to both sides of the length direction of the scattering lens. The beneficial effect is that when hyperspectral aerial photography is performed, the length of the scattering lens photographed is much larger than the width of the light source, which can meet the imaging requirements of low-resolution hyperspectral aerial photography, and the linear light source can be more clearly imaged than the point-shaped light source, which is convenient for high-precision positioning.

Description

Technical Field

[0001] The present invention relates to the field of hyperspectral technology, in particular to a ground marker used for hyperspectral aerial photography. Background Art

[0002] During aerial imaging, ground landmarks are obvious and clear positioning identification marks on the image. Currently, road intersections, river crossings, building boundaries, farmland boundaries, etc. are commonly used. However, for hyperspectral aerial photography, there are usually hundreds of bands, and the wavelength range of each band is only a few nanometers. Since each band is imaged separately, only the light within the wavelength range can be imaged in the band. Therefore, the above-mentioned ground landmarks may not have clear images in many bands. For example, in a certain band of visible red light in the hyperspectral spectrum, only the red light within the band can be imaged, and the ground landmarks within the above-mentioned visible light wavelength range may not be clearly imaged. For example, in a certain band of near-infrared light in the hyperspectral spectrum, only the near-red light within the band can be imaged, and the ground landmarks within the above-mentioned visible light wavelength range may not be clearly imaged. Summary of the Invention

[0003] The main problem solved by the present invention is how to enable clear imaging of ground signs in all wavebands of hyperspectral aerial photography.

[0004] A ground marker for hyperspectral aerial photography, characterized in that it includes a light source, a scattering lens, and a shell. The scattering lens is in the shape of an elongated strip. The light source includes a visible light source and a near-infrared light source. The light source is located directly below the scattering lens. The width of the light source is less than the length of the scattering lens. The light emitted by the light source passes through the scattering lens and then diverges to both sides of the length direction of the scattering lens. The shell fixes the relative position of the light source and the scattering lens. The shell is provided with a mounting end, which can fix the ground marker on the ground. The shell also includes two reflectors, which form a V-shape. The reflective surfaces are located on the left and right outsides of the V-shape. The reflectors are located directly below the scattering lens and directly above the light source.

[0005] The beneficial effect is that the width of the light source is smaller than the length of the scattering lens, and the light emitted by the light source diverges to both sides of the length direction of the scattering lens after passing through the scattering lens. Therefore, when hyperspectral aerial imaging is performed, the length of the scattering lens captured is much larger than the width of the light source, which can meet the imaging requirements of hyperspectral aerial photography (because hyperspectral aerial photography has many bands and its spatial resolution is usually low, a sufficient length is required for clear imaging). Moreover, a linear light source can be more clearly imaged than a point light source, which facilitates high-precision positioning. Moreover, since the light source is located directly below the scattering lens, the midpoint of the scattering lens captured in the length direction is the position of the ground mark, which is accurately positioned. The two reflectors can block the area directly above the light source, which is equivalent to dividing the scattering lens into two sections, so that the midpoint of the scattering lens is the darkest during hyperspectral aerial imaging, which facilitates identification and positioning. Secondly, the reflector can reflect the light emitted by the light source below it to the scattering lenses on both sides, making full use of the light emitted by the light source, while enhancing the intensity of the light scattered from both sides of the scattering lens, further improving the recognition accuracy of hyperspectral aerial photography. The light source includes visible and near-infrared light sources, such as the widely used tungsten lamp. This allows the ground markers to be imaged across most hyperspectral bands. Within the visible and near-infrared bands, when geometrically correcting two images taken at different times and in different bands (including image correction between hyperspectral and multispectral images), the ground markers can be simultaneously identified. The greater the number of ground markers, the better. These markers are distributed on the ground at a certain density, resulting in better geometric correction of the hyperspectral aerial imagery and more accurate matching of the actual geographic coordinates of each ground point.

[0006] Hyperspectral aerial photography, as described in this invention, refers to aerial photography performed using a hyperspectral camera mounted on an aircraft or satellite, referred to as hyperspectral airborne aerial photography and hyperspectral satellite aerial photography, respectively. Because satellites are farther from the ground, the resolution of hyperspectral satellite aerial photography is typically lower than that of hyperspectral airborne aerial photography. Therefore, when using the marker for hyperspectral satellite aerial photography, its size should be appropriately increased to ensure clear imaging.

[0007] The cross section of the scattering lens is semicircular, with the arc surface facing upward.

[0008] The beneficial effect is that the semicircle allows the light emitted by the light source to diverge in all directions after passing through the scattering lens, so that clear images can be obtained during hyperspectral aerial photography at different angles.

[0009] The length direction of the scattering lens is toward the north-south or east-west direction of the geographical coordinates.

[0010] The beneficial effect is that, accordingly, the perpendicular bisector of the length direction of the scattering lens faces east-west or north-south, so the ground marker has directionality, so that the ground marker has direction reference and correction functions during hyperspectral aerial imaging.

[0011] It also includes a power supply and a switch. The power supply, the switch and the light source form an electrical circuit. When hyperspectral aerial photography is being taken, the switch is turned on and the light source is illuminated.

[0012] The beneficial effect is that the light source is only turned on when hyperspectral aerial photography is needed, which can save energy. The power supply can be a solar power source, using daytime sunlight to store energy, and the light can be turned on and off remotely by remote control at any time.

[0013] The light source covers the spectral range of hyperspectral imaging, including ultraviolet light source, visible light, near-infrared light source, and mid- and far-infrared light source. Among them, the ultraviolet light source is a deuterium lamp, the visible light and near-infrared light source are tungsten lamps, and the mid- and far-infrared light source are silicon carbide rods.

[0014] The beneficial effect is that the light source covers the spectral range of hyperspectral imaging, so the ground marker can be imaged in almost all hyperspectral bands. When geometric correction is performed on two images captured at different times and in different bands (including image correction between hyperspectral and multispectral images), the ground marker can be simultaneously identified. The deuterium lamp, tungsten lamp, and silicon carbide rod can basically cover the spectral range of hyperspectral imaging, making the combination simple and highly practical. The deuterium lamp mainly functions as an ultraviolet light source, emitting light with a wavelength generally ranging from 190 to 400 nm, a continuous spectral band. The operating principle of the deuterium lamp is mainly based on plasma discharge, that is, the deuterium lamp is always kept in a stable deuterium (D2 or deuterium) arc state. When powered, the cathode plasma discharge generates electron emission. The high-speed electrons collide and react with atoms in the high-purity deuterium gas, generating a continuous ultraviolet spectral band with a wavelength range of 190 to 400 nm. The wavelength range of the tungsten lamp mainly covers the visible spectrum and the near-infrared region. Tungsten lamps are one of the most commonly used light sources in hyperspectral analysis. As the most commonly used visible light source, tungsten lamps offer high brightness, high stability, and a long lifespan. They can emit a continuous spectrum with a wavelength of 325 to 2500 nm, and therefore can also be used as a near-infrared light source. When heated by electricity, silicon carbide rods emit near-blackbody radiation in the wavelength range of 2000 to 20,000 nm, representing a mid- to far-infrared light source.

[0015] A ground marker for hyperspectral aerial photography comprises a light source, a scattering lens, and a shell. The scattering lens is in the shape of an elongated strip. There are two scattering lenses that intersect to form a cross. The light source comprises a visible light source and a near-infrared light source. The light source is located directly below the scattering lens. The width of the light source is less than the length of the scattering lens. Light emitted by the light source passes through the scattering lens and then diverges to both sides in the length direction of the scattering lens. The shell fixes the relative position of the light source and the scattering lens. The shell is provided with a mounting end that can fix the ground marker on the ground. The shell also comprises four reflectors, which are respectively located on the four sides of a tetrahedron. The tetrahedron is located directly below the scattering lens and directly above the light source. The tetrahedron is inverted.

[0016] The beneficial effect is that there are two scattering lenses, which cross each other to form a cross shape. Therefore, the center point of the cross is the position of the ground mark, and the positioning is more accurate during hyperspectral aerial imaging. In addition, the width of the light source is smaller than the length of the scattering lens. The light emitted by the light source passes through the scattering lens and diverges to both sides of the length direction of the scattering lens. Therefore, during hyperspectral aerial imaging, the length of the scattering lens photographed is much larger than the width of the light source, which can meet the imaging requirements of low-resolution hyperspectral aerial photography. Moreover, the linear light source can be more clearly imaged than the point light source, which is convenient for high-precision positioning. The tetrahedron can block the light source directly above, which is equivalent to dividing the scattering lens into 4 sections, so that the center point of the scattering lens is the darkest during hyperspectral aerial imaging, which is convenient for identification and positioning. Secondly, the reflector can reflect the light emitted by the light source below it to the scattering lenses on both sides, making full use of the light emitted by the light source, while enhancing the light intensity scattered from both sides of the scattering lens, further improving the recognition accuracy of hyperspectral aerial photography. The light source includes visible and near-infrared light sources, such as the widely used tungsten lamp. This allows the ground markers to be imaged across most hyperspectral bands. Within the visible and near-infrared bands, when geometrically correcting two images taken at different times and in different bands (including image correction between hyperspectral and multispectral images), the ground markers can be simultaneously identified. The greater the number of ground markers, the better. These markers are distributed on the ground at a certain density, resulting in better geometric correction of the hyperspectral aerial imagery and more accurate matching of the actual geographic coordinates of each ground point.

[0017] The upper surface of the shell is provided with light absorbing material except for the position where the scattering lens is located.

[0018] The beneficial effect is that the light-absorbing material absorbs the vast majority of the light emitted by the light source, resulting in the upper surface of the housing scattering almost no light except where the scattering lens is located. This surface appears black to the human eye and appears black in all hyperspectral bands, creating a sharp contrast with the location of the scattering lens, facilitating clearer imaging. The light-absorbing material refers to materials capable of absorbing ultraviolet, visible, and infrared light, including black paint, carbon fiber, carbon nanotubes, and the like.

[0019] The cross section of the scattering lens is semicircular, with the arc surface facing upward; the cross shape points to the east, south, west and north directions of the geographical coordinates.

[0020] The beneficial effect is that the semicircle allows the light emitted by the light source to diverge in all directions after passing through the scattering lens, so that clear images can be obtained during hyperspectral aerial photography at different angles; the ground mark has directionality, so that the ground mark has direction reference and correction functions during hyperspectral aerial imaging.

[0021] It also includes a power supply and a switch. The power supply, the switch and the light source form an electrical circuit. When hyperspectral aerial photography is being taken, the switch is turned on and the light source is illuminated.

[0022] The beneficial effect is that the light source is only turned on when hyperspectral aerial photography is needed, which can save energy. The power supply can be a solar power source, using daytime sunlight to store energy, and the light can be turned on and off remotely by remote control at any time.

[0023] The light source covers the spectral range of hyperspectral imaging, including ultraviolet light source, visible light, near-infrared light source, and mid- and far-infrared light source. Among them, the ultraviolet light source is a deuterium lamp, the visible light and near-infrared light source are tungsten lamps, and the mid- and far-infrared light source are silicon carbide rods.

[0024] The beneficial effect is that the light source covers the spectral range of hyperspectral imaging, so the ground marker can be imaged in almost all hyperspectral bands. When geometrically correcting two images captured at different times and in different bands (including image correction between hyperspectral and multispectral images), the ground marker can be simultaneously identified, ensuring that the two images share a common ground marker. Geometric correction can be achieved by matching the common ground marker. Furthermore, when geometrically correcting images captured at different bands during the same time period by the same hyperspectral camera, since the images in different bands also share a common ground marker, geometric distortion correction is also facilitated. The deuterium lamp, tungsten lamp, and silicon carbide rod can essentially cover the spectral range of hyperspectral imaging, providing a simple combination and high practicality. The deuterium lamp primarily serves as a source of ultraviolet light, emitting light with a wavelength generally ranging from 190 to 400 nm, a continuous spectral band. The deuterium lamp operates primarily on the principle of plasma discharge, which means that the deuterium lamp is always maintained in a stable deuterium (D2 or deuterium) arc state. When powered, cathode plasma discharges, generating electron emission. These high-speed electrons collide and react with atoms in the high-purity deuterium gas, producing a continuous ultraviolet spectrum with a wavelength range of 190 to 400 nm. Tungsten lamps primarily cover the visible and near-infrared regions. Tungsten lamps are one of the most commonly used light sources in hyperspectral analysis. As the most commonly used visible light source, tungsten lamps offer high brightness, high stability, and a long lifespan. They emit a continuous spectrum with a wavelength range of 325 to 2500 nm, making them suitable for near-infrared applications. When heated by electrical current, silicon carbide rods emit near-blackbody radiation in the 2000 to 20,000 nm wavelength range, representing a mid- to far-infrared source. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 . A schematic diagram of the overall structure of an embodiment;

[0026] Figure 2 .Schematic diagram of the scattering lens structure;

[0027] Figure 3 .Schematic diagram of the reflector and light source structure;

[0028] Figure 4 .Schematic diagram of ground landmark imaging during hyperspectral aerial photography;

[0029] Figure 5 . A schematic diagram of the overall structure of an embodiment;

[0030] Figure 6 .Schematic diagram of the scattering lens structure;

[0031] Figure 7 .Schematic diagram of the reflector and light source structure;

[0032] Figure 8. Schematic diagram of ground landmark imaging during hyperspectral aerial photography.

[0033] In the figure: 1. light source, 2. scattering lens, 3. housing, 4. reflector. DETAILED DESCRIPTION

[0034] Example

[0035] like Figure 1-4 As shown, a ground marker for hyperspectral aerial photography is characterized by including a light source, a scattering lens, and a shell. The scattering lens is in the shape of an elongated strip. The light source includes a visible light source and a near-infrared light source. The light source is located directly below the scattering lens. The width of the light source is smaller than the length of the scattering lens. The light emitted by the light source passes through the scattering lens and then diverges to both sides of the length direction of the scattering lens. The shell fixes the relative position of the light source and the scattering lens. The shell is provided with a mounting end, and the mounting end can fix the ground marker on the ground. The shell also includes two reflectors, which form a V shape. The reflective surfaces are located on the left and right outsides of the V shape. The reflectors are located directly below the scattering lens and directly above the light source.

[0036] The cross section of the scattering lens is semicircular, with the arc surface facing upward.

[0037] The length direction of the scattering lens is toward the north-south or east-west direction of the geographical coordinates.

[0038] It also includes a power supply and a switch. The power supply, the switch and the light source form an electrical circuit. When hyperspectral aerial photography is being taken, the switch is turned on and the light source is illuminated.

[0039] The light source covers the spectral range of hyperspectral imaging, including ultraviolet light source, visible light, near-infrared light source, and mid- and far-infrared light source. Among them, the ultraviolet light source is a deuterium lamp, the visible light and near-infrared light source are tungsten lamps, and the mid- and far-infrared light source are silicon carbide rods.

[0040] Example

[0041] like Figure 5-8As shown, a ground marker for hyperspectral aerial photography includes a light source, a scattering lens, and a shell. The scattering lens is in the shape of an elongated strip. There are two scattering lenses that cross each other to form a cross. The light source includes a visible light source and a near-infrared light source. The light source is located directly below the scattering lens. The width of the light source is smaller than the length of the scattering lens. The light emitted by the light source passes through the scattering lens and then diverges to both sides of the length direction of the scattering lens. The shell fixes the relative position of the light source and the scattering lens. The shell is provided with a mounting end, and the mounting end can fix the ground marker on the ground. The shell also includes 4 reflectors, which are respectively located on the 4 sides of a tetrahedron. The tetrahedron is located directly below the scattering lens and directly above the light source. The tetrahedron is inverted.

[0042] The upper surface of the shell is provided with light absorbing material except for the position where the scattering lens is located.

[0043] The cross section of the scattering lens is semicircular, with the arc surface facing upward; the cross shape points to the east, south, west and north directions of the geographical coordinates.

[0044] It also includes a power supply and a switch. The power supply, the switch and the light source form an electrical circuit. When hyperspectral aerial photography is being taken, the switch is turned on and the light source is illuminated.

[0045] The light source covers the spectral range of hyperspectral imaging, including ultraviolet light source, visible light, near-infrared light source, and mid- and far-infrared light source. Among them, the ultraviolet light source is a deuterium lamp, the visible light and near-infrared light source are tungsten lamps, and the mid- and far-infrared light source are silicon carbide rods.

Claims

1. A ground marker for hyperspectral aerial photography, characterized by: The ground sign comprises a light source, a scattering lens, and a shell. The scattering lens is in the shape of an elongated strip. The light source comprises a visible light source and a near-infrared light source. The light source is located directly below the scattering lens. The width of the light source is smaller than the length of the scattering lens. The light emitted by the light source passes through the scattering lens and diverges to both sides of the length direction of the scattering lens. The shell fixes the relative position of the light source and the scattering lens. The shell is provided with a mounting end, and the mounting end can fix the ground sign on the ground. The shell also comprises two reflectors. The two reflectors form a V shape, and the reflective surfaces thereof are located on the left and right outer sides of the V shape. The reflectors are located directly below the scattering lens and directly above the light source. The width of the light source is smaller than the length of the scattering lens. The light emitted by the light source passes through the scattering lens and then diverges to both sides of the length direction of the scattering lens. Therefore, during hyperspectral aerial imaging, the length of the scattering lens captured is greater than the width of the light source.

2. A ground marker for hyperspectral aerial photography according to claim 1, characterized in that: The cross section of the scattering lens is semicircular, with the arc surface facing upward.

3. The ground marker for hyperspectral aerial photography according to claim 1, characterized in that: The length direction of the scattering lens is toward the north-south or east-west direction of the geographical coordinates.

4. The ground marker for hyperspectral aerial photography according to claim 1, characterized in that: It also includes a power supply and a switch. The power supply, the switch and the light source form an electrical circuit. When hyperspectral aerial photography is being taken, the switch is turned on and the light source is illuminated.

5. The ground marker for hyperspectral aerial photography according to claim 1, characterized in that: The light source covers the spectral range of hyperspectral imaging, including ultraviolet light source, visible light, near-infrared light source, and mid- and far-infrared light source. Among them, the ultraviolet light source is a deuterium lamp, the visible light and near-infrared light source are tungsten lamps, and the mid- and far-infrared light source are silicon carbide rods.

6. A ground marker for hyperspectral aerial photography, comprising a light source, a scattering lens, and a shell. The scattering lens is in the shape of an elongated strip. There are two scattering lenses that cross each other to form a cross. The light source comprises a visible light source and a near-infrared light source. The light source is located directly below the scattering lens. The width of the light source is smaller than the length of the scattering lens. The light emitted by the light source passes through the scattering lens and then diverges to both sides of the length direction of the scattering lens. Therefore, during hyperspectral aerial photography, the length of the scattering lens photographed is greater than the width of the light source. The shell fixes the relative position of the light source and the scattering lens. The shell is provided with a mounting end, which can fix the ground marker on the ground. The shell also comprises four reflectors, which are respectively located on the four sides of a tetrahedron. The tetrahedron is located directly below the scattering lens and directly above the light source. The tetrahedron is inverted.

7. A ground marker for hyperspectral aerial photography according to claim 6, characterized in that: The upper surface of the shell is provided with light absorbing material except for the position where the scattering lens is located.

8. The ground marker for hyperspectral aerial photography according to claim 6, characterized in that: The cross section of the scattering lens is semicircular, with the arc surface facing upward; the cross shape points to the east, south, west and north directions of the geographical coordinates.

9. The ground marker for hyperspectral aerial photography according to claim 6, characterized in that: It also includes a power supply and a switch. The power supply, the switch and the light source form an electrical circuit. When hyperspectral aerial photography is being taken, the switch is turned on and the light source is illuminated.

10. The ground marker for hyperspectral aerial photography according to claim 6, characterized in that: The light source covers the spectral range of hyperspectral imaging, including ultraviolet light source, visible light, near-infrared light source, and mid- and far-infrared light source. Among them, the ultraviolet light source is a deuterium lamp, the visible light and near-infrared light source are tungsten lamps, and the mid- and far-infrared light source are silicon carbide rods.

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