Image quality screening method based on solar incident angle

Abstract

An image quality screening method based on a sun incident angle comprises the following steps: determining shooting time of a picture according to picture information of the picture to be screened; calculating the zenith angle, the azimuth angle, the declination angle and the hour angle of the sun according to the latitude and longitude of the shot picture and the shooting time; according to the zenith angle, the azimuth angle, the declination angle and the hour angle of the sun, analyzing the irradiation angle of the sunlight by using an analysis tool; through inputting latitude and longitude, date and time, a current sunlight irradiation angle is simulated by using a GIS tool, and pictures meeting conditions are screened out. According to the method, the sun incident angle is adopted to screen the image quality, the situation that light rays irradiate the earth surface at a more inclined angle due to the small sun elevation angle is avoided, the shadow area is increased, the definition and color saturation of the image are reduced, and it is avoided that in the areas with multiple rugged topographies and tall ground features, the image quality is improved. And data acquisition and processing can be optimized in a high-latitude region, so that satellite images with higher quality can be obtained.

Description

Technical Field

[0001] The invention relates to the technical field of image quality screening, and in particular to an image quality screening method based on the sun's incident angle. Background Art

[0002] The solar incidence angle is the angle between the direct sunlight and the wall normal. The solar incidence angle changes with the solar altitude angle, azimuth, wall azimuth, and wall inclination. The solar incidence angle is needed to implement the image quality screening process, so an image quality screening method based on the solar incidence angle is needed. In the prior art, the images screened out by the traditional image quality screening method have poor clarity, severe shadow effects, and cannot adapt to special terrain conditions, resulting in poor quality of satellite images. Therefore, an image quality screening method based on the solar incidence angle is urgently needed to solve this problem. Summary of the invention

[0003] In view of the above problems, the present invention is proposed to provide an image quality screening method based on the solar incident angle, which overcomes the above problems or at least partially solves the above problems.

[0004] In order to solve the above technical problems, the embodiments of the present application disclose the following technical solutions:

[0005] The embodiment of the present invention discloses an image quality screening method based on the solar incident angle, comprising:

[0006] S100. Determine the shooting time of the picture according to the picture information of the picture to be screened;

[0007] S200. Calculate the solar zenith angle, azimuth angle, solar declination angle and hour angle according to the longitude and latitude of the captured image and the shooting time;

[0008] S300. Analyze the angle of sunlight using an analysis tool according to the solar zenith angle, azimuth angle, solar declination angle and hour angle;

[0009] S400. By inputting the longitude and latitude, date and time, using GIS tools to simulate the sunlight angle at that time, filter out the pictures that meet the conditions.

[0010] Furthermore, in S100, the shooting time of the picture is determined according to the picture information of the picture to be screened, and the specific method includes:

[0011] The shooting time can be inferred by obtaining metadata in the image information or judging by the natural light and shadow in the image. If the direction and length of the shadow of the object in the image are consistent with the local time, the shooting time can be inferred. First, by observing the position of the sun in the image, the approximate time period of the shooting can be preliminarily judged. Then, the shooting time can be inferred by measuring the angle and length of the shadow in the image, combined with the changing patterns of the sun's altitude and azimuth angles.

[0012] Furthermore, in S200, the solar zenith angle is the angle between the sun's rays and the vertical line of the ground, the azimuth angle is the angle between the projection of the sun's rays on the horizontal plane and the south direction; the solar declination angle is the angle between the earth's equatorial plane and the line connecting the sun and the center of the earth; the solar hour angle is the angular distance from the celestial meridian circle of the observation point along the celestial equator to the hour circle where the sun is located. When the time is 12 o'clock, the solar hour angle is 0°, and then every 1 hour, the hour angle increases by 15°.

[0013] Furthermore, the solar zenith angle ranges from 0° to 180°, and the solar zenith angle calculation formula is:

[0014] Solar zenith angle = 90°-θ, θ is the solar altitude angle;

[0015] The calculation formula of the solar altitude angle θ is:

[0016] cos(θ)=sin(δ)sin(φ)+cos(δ)cos(φ)cos(H);

[0017] Among them, θ is the solar altitude angle, δ is the solar declination, φ is the latitude of the location, and H is the solar hour angle; the solar declination is the angle of the sun relative to the Earth's equator, which is +23.5° at the summer solstice, -23.5° at the winter solstice, and 0° at the vernal and autumnal equinoxes; the solar hour angle is the angle of the sun relative to the local meridian. The solar hour angle calculation formula is H=15*(t-12)+λ, where t is the local standard time and λ is the local longitude.

[0018] Furthermore, in S300, an analysis tool is used to analyze the angle of sunlight. The specific method includes: using the analysis tool Ecotect to simulate sunlight exposure conditions, analyzing the impact of sunlight exposure angles on buildings at different times and seasons, and by inputting a simple model, Ecotect provides a digital visual analysis diagram.

[0019] Furthermore, in S400, a GIS tool is used to simulate the sunlight angle at that time and select the pictures that meet the conditions. The specific method includes:

[0020] S401. Converting the vector data of the object height into raster data;

[0021] S402. Reclassify the converted raster data, and change the "NoData" value of the edge of the object to 0, so as to ensure that the elevation value of the edge of the object can be correctly calculated in the subsequent aspect calculation;

[0022] S403. Use the "Aspect" tool in the Spatial Analyst tool to calculate the aspect of the original DEM data. After obtaining the aspect raster data, use the "Reclassify" tool to reclassify the aspect raster data according to the statistical geological disaster information or other relevant standards. Reclassification is the process of reclassifying the pixel values ​​in the original raster data into new categories or ranges for better subsequent analysis or application. Finally, the aspect of the reclassified raster data is obtained through calculation;

[0023] S404. Obtain the solar altitude angle and solar azimuth angle, wherein the solar altitude angle is the angle between the solar ray and the horizontal plane, that is, the solar incidence angle θ, and the solar azimuth angle is the angle between the solar ray projected onto the horizontal plane and the true north direction, that is, the latitude φ;

[0024] S405. Using the solar altitude angle and azimuth angle to calculate the illumination, by setting the preset time and location in the GIS software, calculate the solar altitude angle and azimuth angle at that moment, and then simulate the shadow range of the object;

[0025] S406. Generate a sunshine map within a specific time period through S401-S405.

[0026] Furthermore, in step S401, the specific operation of converting the vector data of the object height into raster data includes: using the "Convert to Raster" tool in ArcMap to convert the vector data of the object height into raster data.

[0027] Furthermore, in step S404, the solar altitude angle and the solar azimuth angle are expressed in a spherical coordinate system, wherein the solar incidence angle θ represents the angle rotated clockwise from the z-axis to the azimuth of the object, and the dimension φ represents the angle rotated counterclockwise from the x-axis to the azimuth of the object.

[0028] Furthermore, in the step S405, if the shadow range of the simulated object is not blocked within the shadow range at 12 noon, it is considered that the object spacing meets the sunlight requirement.

[0029] Furthermore, the calculation formula of the sunlight irradiation angle is:

[0030] Cosθ1=sinα*cosh*cosA+cosα*sinh

[0031] Among them, θ1 is the solar incidence angle, α is the front roof angle of the greenhouse, h is the solar altitude angle, and A is the solar azimuth angle;

[0032] For a tilted solar device, the relationship between the solar incident angle θ1 and the solar altitude angle h is θ1 = 90°-h; when the wall is upright, the calculation formula for the solar incident angle is:

[0033] cosi=cosh*cosA-sinh*sinA

[0034] Among them, i is the solar incidence angle, h is the solar altitude angle, and A is the solar azimuth angle on the wall.

[0035] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0036] The present invention discloses an image quality screening method based on the solar incident angle, comprising: determining the shooting time of the image according to the image information of the image to be screened; calculating the solar zenith angle, azimuth angle, solar declination angle and hour angle according to the longitude and latitude of the image and the shooting time; using an analysis tool to analyze the irradiation angle of sunlight according to the solar zenith angle, azimuth angle, solar declination angle and hour angle; simulating the irradiation angle of sunlight at that time by inputting the longitude and latitude, date and time, and screening out the images that meet the conditions. The present invention uses the solar incident angle to screen the image quality to avoid the situation that a smaller solar altitude angle causes the light to irradiate the surface at a more inclined angle, increasing the shadow area, thereby reducing the clarity and color saturation of the image, and preventing the smaller solar altitude angle from causing the shadow area to expand in areas with undulating terrain and more tall objects, thereby affecting the accuracy of object classification and stereoscopic projects, and can optimize data collection and processing in high-latitude areas, thereby obtaining higher-quality satellite images.

[0037] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0039] Figure 1 This is a flow chart of an image quality screening method based on the solar incidence angle in Example 1 of the present invention. DETAILED DESCRIPTION

[0040] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0041] In order to solve the problems existing in the prior art, an embodiment of the present invention provides an image quality screening method based on the solar incident angle.

[0042] Example 1

[0043] The present invention discloses a method for screening image quality based on the sun's incident angle. Figure 1 ,include:

[0044] S100. Determine the shooting time of the picture according to the picture information of the picture to be filtered; in S100 of the present embodiment, determine the shooting time of the picture according to the picture information of the picture to be filtered, and the specific method includes: obtaining through metadata in the picture information or judging through natural light and shadow in the picture, if the direction and length of the shadow of the object in the picture are consistent with the local time, infer the shooting time; first, by observing the position of the sun in the picture, preliminarily judge the approximate time period of the shooting, and then measure the angle and length of the shadow in the picture, combined with the change law of the sun's altitude angle and azimuth angle, to infer the shooting time.

[0045] Specifically, the shooting time of the picture in step S100 is determined by obtaining metadata of the picture or judging by natural light and shadow in the picture; if the direction and length of the shadow of the object in the picture are consistent with the local time, the shooting time can be inferred;

[0046] First, by observing the position of the sun in the picture, you can preliminarily determine the approximate time period of the photo. For example, when the sun is at the highest point in the sky, it is usually noon; when the sun is close to the horizon, it may be early morning or evening.

[0047] Secondly, the shadow of the object in the picture is also an important basis for judging the shooting time. The angle and length of the shadow are closely related to the altitude and azimuth of the sun. As the sun moves in the sky, the direction and length of the shadow will also change. Therefore, by measuring the angle and length of the shadow in the picture, combined with the changing patterns of the altitude and azimuth of the sun, the shooting time can be inferred.

[0048] S200. Calculate the sun's zenith angle, azimuth angle, solar declination angle and hour angle according to the longitude and latitude of the taken picture and the shooting time; in S200 of the present embodiment, the sun's zenith angle is the angle between the sun's rays and the vertical line of the ground, the azimuth angle is the angle between the projection of the sun's rays on the horizontal plane and the south direction; the solar declination angle is the angle between the earth's equatorial plane and the line connecting the sun and the center of the earth; the solar hour angle is the angular distance from the celestial meridian circle of the observation point along the celestial equator to the hour circle where the sun is located, when the time is 12 o'clock, the solar hour angle is 0°, and then every 1 hour, the hour angle increases by 15°.

[0049] In this embodiment, the zenith angle of the sun ranges from 0° to 180°, and the calculation formula for the zenith angle of the sun is:

[0050] Solar zenith angle = 90°-θ, θ is the solar altitude angle;

[0051] The calculation formula of the solar altitude angle θ is:

[0052] cos(θ)=sin(δ)sin(φ)+cos(δ)cos(φ)cos(H);

[0053] Among them, θ is the solar altitude angle, δ is the solar declination, φ is the latitude of the location, and H is the solar hour angle; the solar declination is the angle of the sun relative to the Earth's equator, which is +23.5° at the summer solstice, -23.5° at the winter solstice, and 0° at the vernal and autumnal equinoxes; the solar hour angle is the angle of the sun relative to the local meridian. The solar hour angle calculation formula is H=15*(t-12)+λ, where t is the local standard time and λ is the local longitude.

[0054] S300. Analyze the angle of sunlight using an analysis tool according to the solar zenith angle, azimuth angle, solar declination angle and hour angle;

[0055] In S300 of this embodiment, an analysis tool is used to analyze the angle of sunlight. The specific method includes: using the analysis tool Ecotect to simulate sunlight exposure conditions, analyzing the impact of sunlight exposure angles on buildings at different times and seasons, and by inputting a simple model, Ecotect provides a digital visual analysis diagram.

[0056] S400. By inputting the longitude and latitude, date and time, using GIS tools to simulate the sunlight angle at that time, filter out the pictures that meet the conditions.

[0057] In S400 of this embodiment, a GIS tool is used to simulate the sunlight angle at that time and to screen out pictures that meet the conditions. The specific method includes:

[0058] S401. Converting the vector data of the object height into raster data;

[0059] S402. Reclassify the converted raster data, and change the "NoData" value of the edge of the object to 0, so as to ensure that the elevation value of the edge of the object can be correctly calculated in the subsequent aspect calculation;

[0060] S403. Use the "Aspect" tool in the Spatial Analyst tool to calculate the aspect of the original DEM data. After obtaining the aspect raster data, use the "Reclassify" tool to reclassify the aspect raster data according to the statistical geological disaster information or other relevant standards. Reclassification is the process of reclassifying the pixel values ​​in the original raster data into new categories or ranges for better subsequent analysis or application. Finally, the aspect of the reclassified raster data is obtained through calculation;

[0061] S404. Obtain the solar altitude angle and solar azimuth angle, wherein the solar altitude angle is the angle between the solar ray and the horizontal plane, that is, the solar incidence angle θ, and the solar azimuth angle is the angle between the solar ray projected onto the horizontal plane and the true north direction, that is, the latitude φ;

[0062] S405. Using the solar altitude angle and azimuth angle to calculate the illumination, by setting the preset time and location in the GIS software, calculate the solar altitude angle and azimuth angle at that moment, and then simulate the shadow range of the object;

[0063] S406. Generate a sunshine map within a specific time period through S401-S405.

[0064] In some preferred embodiments, in step S401, the specific operation of converting the vector data of the object height into raster data includes: using the "Convert to Raster" tool in ArcMap to convert the vector data of the object height into raster data.

[0065] In some preferred embodiments, in step S404, the solar altitude angle and the solar azimuth angle are expressed in a spherical coordinate system, wherein the solar incidence angle θ represents the angle rotated clockwise from the z-axis to the azimuth of the ground object, and the dimension φ represents the angle rotated counterclockwise from the x-axis to the azimuth of the ground object.

[0066] In some preferred embodiments, in the step S405, if the shadow range of the simulated object is not blocked within the shadow range at 12 noon, it is considered that the object spacing meets the sunlight requirement.

[0067] In some preferred embodiments, the calculation formula of the sunlight irradiation angle is:

[0068] Cosθ1=sinα*cosh*cosA+cosα*sinh

[0069] Among them, θ1 is the solar incidence angle, α is the front roof angle of the greenhouse, h is the solar altitude angle, and A is the solar azimuth angle;

[0070] For a tilted solar device, the relationship between the solar incident angle θ1 and the solar altitude angle h is θ1 = 90°-h; when the wall is upright, the calculation formula for the solar incident angle is:

[0071] cosi=cosh*cosA-sinh*sinA

[0072] Among them, i is the solar incidence angle, h is the solar altitude angle, and A is the solar azimuth angle on the wall.

[0073] The present embodiment discloses a method for screening image quality based on the sun's incident angle, including: determining the shooting time of the image according to the image information of the image to be screened; calculating the sun's zenith angle, azimuth angle, solar declination angle and hour angle according to the longitude and latitude of the image and the shooting time; using analysis tools to analyze the angle of sunlight according to the sun's zenith angle, azimuth angle, solar declination angle and hour angle; by inputting the longitude and latitude, date and time, using GIS tools to simulate the angle of sunlight at that time, and screening out images that meet the conditions. The present invention uses the sun's incident angle to screen image quality to avoid the situation that a smaller sun altitude angle causes light to illuminate the surface at a more inclined angle, increasing the shadow area, thereby reducing the clarity and color saturation of the image, and preventing the smaller sun altitude angle from causing the shadow area to expand in areas with undulating terrain and more tall objects, thereby affecting the accuracy of object classification and stereoscopic projects, and can optimize data collection and processing in high-latitude areas, thereby obtaining higher-quality satellite images.

[0074] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0075] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0076] Those skilled in the art will also appreciate that the various illustrative logic blocks, modules, circuits, and algorithmic steps described in conjunction with the embodiments herein can all be implemented as electronic hardware, computer software, or a combination thereof. In order to clearly illustrate the interchangeability between hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above around their functions. Whether such functions are implemented as hardware or software depends on specific applications and the design constraints imposed on the entire system. A skilled person can implement the described functions in an alternative manner for each specific application, but such implementation decisions should not be interpreted as departing from the scope of protection of the present disclosure.

[0077] The steps of the method or algorithm described in conjunction with the embodiments herein may be directly embodied as hardware, a software module executed by a processor, or a combination thereof. The software module may be located in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a mobile disk, a CD-ROM, or any other form of storage medium well known in the art. An exemplary storage medium is connected to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Of course, the storage medium may also be an integral part of the processor. The processor and the storage medium may be located in an ASIC. The ASIC may be located in a user terminal. Of course, the processor and the storage medium may also be present in a user terminal as discrete components.

[0078] For software implementation, the techniques described in this application can be implemented with modules (e.g., procedures, functions, etc.) that perform the functions described in this application. These software codes can be stored in a memory unit and executed by a processor. The memory unit can be implemented within the processor or outside the processor. In the latter case, it is coupled to the processor in a communication manner via various means, which are well known in the art.

[0079] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

Claims

1. An image quality screening method based on solar incidence angle, characterized in that: include: S100. Determine the shooting time of the picture according to the picture information of the picture to be screened; S200. Calculate the solar zenith angle, azimuth angle, solar declination angle and hour angle according to the longitude and latitude of the captured image and the shooting time; S300. Analyze the angle of sunlight using an analysis tool according to the solar zenith angle, azimuth angle, solar declination angle and hour angle; S400. By inputting the longitude and latitude, date and time, using GIS tools to simulate the sunlight angle at that time, filter out the pictures that meet the conditions.

2. The image quality screening method based on solar incident angle according to claim 1, characterized in that: In S100, the shooting time of the picture is determined according to the picture information of the picture to be screened. The specific method includes: obtaining it through the metadata in the picture information or judging by the natural light and shadow in the picture, if the direction and length of the shadow of the object in the picture are consistent with the local time, the shooting time is inferred; first, by observing the position of the sun in the picture, the approximate time period of the shooting is preliminarily judged, and then by measuring the angle and length of the shadow in the picture, combined with the change law of the altitude angle and azimuth angle of the sun, the shooting time is inferred.

3. The image quality screening method based on solar incident angle according to claim 1, characterized in that: In S200, the solar zenith angle is the angle between the sun's rays and the vertical line of the ground, the azimuth angle is the angle between the projection of the sun's rays on the horizontal plane and the south direction; the solar declination angle is the angle between the earth's equatorial plane and the line connecting the sun and the center of the earth; the solar hour angle is the angular distance from the celestial meridian circle of the observation point along the celestial equator to the hour circle where the sun is located. When the time is 12 o'clock, the solar hour angle is 0°, and then every 1 hour, the hour angle increases by 15°.

4. The image quality screening method based on solar incident angle according to claim 3, characterized in that: The solar zenith angle ranges from 0° to 180°, and the solar zenith angle calculation formula is: Solar zenith angle = 90°-θ, θ is the solar altitude angle; The calculation formula of the solar altitude angle θ is: cos(θ)=sin(δ)sin(φ)+cos(δ)cos(φ)cos(H); Among them, θ is the solar altitude angle, δ is the solar declination, φ is the latitude of the location, and H is the solar hour angle; the solar declination is the angle of the sun relative to the Earth's equator, which is +23.5° at the summer solstice, -23.5° at the winter solstice, and 0° at the vernal and autumnal equinoxes; the solar hour angle is the angle of the sun relative to the local meridian. The solar hour angle calculation formula is H=15*(t-12)+λ, where t is the local standard time and λ is the local longitude.

5. The image quality screening method based on solar incident angle according to claim 1, characterized in that: In S300, analysis tools are used to analyze the angle of sunlight. The specific methods include: using the analysis tool Ecotect to simulate sunlight exposure conditions, analyzing the impact of sunlight exposure angles on buildings at different times and seasons, and by inputting a simple model, Ecotect provides a digital visual analysis diagram.

6. The image quality screening method based on solar incident angle according to claim 1, characterized in that: In S400, GIS tools are used to simulate the sunlight angle at that time and select the pictures that meet the conditions. The specific methods include: S401. Converting the vector data of the object height into raster data; S402. Reclassify the converted raster data and change the "NoData" value of the object edge to 0 to ensure that the elevation value of the object edge can be correctly calculated in the subsequent slope aspect calculation; S403. Use the "Aspect" tool in the Spatial Analyst tool to calculate the aspect of the original DEM data. After obtaining the aspect raster data, use the "Reclassify" tool to reclassify the aspect raster data according to the statistical geological disaster information or other relevant standards. Reclassification is the process of reclassifying the pixel values ​​in the original raster data into new categories or ranges for better subsequent analysis or application. Finally, the aspect of the reclassified raster data is calculated; S404. Obtain the solar altitude angle and solar azimuth angle, wherein the solar altitude angle is the angle between the solar ray and the horizontal plane, that is, the solar incidence angle θ, and the solar azimuth angle is the angle between the solar ray projected onto the horizontal plane and the true north direction, that is, the latitude φ; S405. Using the solar altitude angle and azimuth angle to calculate the illumination, by setting the preset time and location in the GIS software, calculate the solar altitude angle and azimuth angle at that moment, and then simulate the shadow range of the object; S406. Generate a sunshine map within a specific time period through S401-S405.

7. The image quality screening method based on solar incident angle according to claim 6, characterized in that: In the step S401, the vector data of the height of the object is converted into raster data. The specific operation includes: using the "Convert to Raster" tool in ArcMap to convert the vector data of the height of the object into raster data.

8. The image quality screening method based on solar incident angle according to claim 6, characterized in that: In step S404, the solar altitude angle and the solar azimuth angle are expressed in a spherical coordinate system, wherein the solar incidence angle θ represents the angle from the z-axis rotated clockwise to the azimuth of the object, and the dimension φ represents the angle from the x-axis rotated counterclockwise to the azimuth of the object.

9. The image quality screening method based on solar incident angle according to claim 6, characterized in that: In the step S405, if the shadow range of the simulated object is not blocked within the shadow range at 12 noon, it is considered that the object spacing meets the sunlight requirement.

10. The image quality screening method based on solar incident angle according to claim 1, characterized in that: The calculation formula of the sunlight irradiation angle is: Cosθ1=sinα*cosh*cosA+cosα*sinh Among them, θ1 is the solar incidence angle, α is the front roof angle of the greenhouse, h is the solar altitude angle, and A is the solar azimuth angle; For a tilted solar device, the relationship between the solar incident angle θ1 and the solar altitude angle h is θ1 = 90°-h; when the wall is upright, the calculation formula for the solar incident angle is: cosi=cosh*cosA-sinh*sinA Among them, i is the solar incidence angle, h is the solar altitude angle, and A is the solar azimuth angle on the wall.

Images