KR102577435B1 - Method for mitigation of topographic effect in infrared images taken from geostationary orbit imaging system and Apparatus Thereof - Google Patents

Abstract

The present invention relates to a method and device for reducing altitude effects in geostationary orbit infrared images. More specifically, the present invention relates to a ground temperature image based on an infrared channel image taken from a satellite operating in geostationary orbit, and the estimated ground temperature. This relates to a method and device for reducing altitude effects in geostationary infrared images to minimize the effects of altitude changes shown in images.

Description

Method for mitigation of topographic effect in infrared images taken from geostationary orbit imaging system and Apparatus Thereof}

The present invention relates to a method and device for reducing the effect of altitude in geostationary infrared images, and more specifically, to obtain a ground temperature image from an infrared channel image captured by a satellite operating in geostationary orbit, and to change altitude in the ground temperature image. It relates to methods and devices for minimizing the impact of

Earth observation satellites that observe the Earth from space have the advantage of being able to monitor human activities and changes in the natural environment by periodically acquiring information about the Earth's surface by traveling around the Earth along the satellite's orbit.

Among various satellite orbits, geostationary orbit is a circular orbit at an altitude of 35,786 km. Geostationary satellites are satellites that take pictures of the Earth's surface in geostationary orbit. Since the satellite's orbital speed and the Earth's rotation speed are the same, they have the advantage of being able to continuously take pictures of the same area. Therefore, because it is possible to quickly respond to weather conditions, ocean currents, and natural disasters that change in real time, advanced countries using satellite images such as the United States, Japan, and Taiwan are operating geostationary satellites, and Korea is also planning to operate geostationary satellites. It is in

Unlike polar orbiting satellites, geostationary satellites have relatively low spatial resolution due to their high orbital altitude, but have the advantage of being able to provide channel images in various wavelength bands.

Just as the rate of temperature decreasing with altitude is defined and utilized as the air temperature lapse rate, the rate of surface temperature decreasing with altitude is defined as the land surface temperature lapse rate and used in infrared images. Research and methods used have been continuously conducted. Related patents include Korean Patent No. 10-1404430, “Method for estimating surface temperature lapse rate using infrared imaging,” and Korean Patent No. 10-1378774, “Method for monitoring time series surface temperature using thermal infrared imaging.” It has been achieved.

However, the methods for estimating altitude effects in satellite imaging systems developed to date are suitable for high-resolution polar orbit satellite imaging systems and are effective for estimating altitude effects in local areas. However, due to the nature of the low-resolution geostationary satellite imaging system that captures the entire Earth, there are limitations in estimating altitude effects in local areas. This is because most areas that appear in geostationary satellite images belong to lowlands, and when the surface temperature lapse rate is estimated in a situation where lowlands are emphasized, it converges close to 0 K/km.

Therefore, in order to reduce the altitude effect in a geostationary satellite imaging system, a surface temperature lapse rate estimation method suitable for geostationary satellite images is required, and a technology that can reduce the altitude effect from the estimated surface temperature lapse rate is needed.

The purpose of the present invention is to reduce the altitude effect that appears in geostationary infrared images.

The purpose of the present invention is to reduce the altitude effect by effectively estimating the altitude effect that appears in geostationary infrared images.

The purpose of the present invention is to estimate the surface temperature lapse rate at the image shooting time and reduce the altitude effect.

The purpose of the present invention is to reduce the altitude effect that appears in geostationary infrared images by using the estimated surface temperature lapse rate.

The purpose of the present invention is to produce a surface temperature image with reduced altitude influence, rather than an actual surface temperature image, by reducing the altitude effect using the estimated surface temperature lapse rate.

The purpose of the present invention is to contribute to the field of infrared satellite image utilization, including forest fire detection, volcanic eruption monitoring, and urban heat island phenomenon monitoring, by producing surface temperature images with reduced altitude effects.

The purpose of the present invention is to improve the performance of algorithmic techniques that can monitor forest fires, volcanic eruptions, etc. by producing surface temperature images with reduced altitude effects.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below. You will be able to.

According to an embodiment of the present invention, an altitude effect reduction device in a geostationary satellite can be provided. At this time, the altitude effect reduction device in the geostationary satellite is the geostationary satellite image acquisition unit, digital elevation model acquisition unit, cloud area removal unit, surface temperature image production unit, sample data selection unit, surface temperature lapse rate estimation unit, and altitude impact reduction unit. May include wealth.

Additionally, the following embodiments can be commonly applied to an altitude effect reduction device in a geostationary orbit satellite and a altitude effect reduction method in a geostationary orbit satellite.

According to an embodiment of the present invention, the image acquisition unit can acquire a geostationary satellite image taken from a geostationary satellite system.

According to an embodiment of the present invention, the digital elevation model acquisition unit may acquire a digital elevation model having the same coordinate system as the geostationary satellite image.

According to an embodiment of the present invention, the cloud area removal unit can detect and remove cloud areas present in the image using the satellite image acquired by the geostationary satellite image acquisition unit.

According to one embodiment of the present invention, the surface temperature image production unit produces a surface temperature image using the infrared satellite image acquired by the geostationary satellite image acquisition unit.

According to an embodiment of the present invention, the sample data selection unit selects sample surface temperature and altitude information for estimating the surface temperature lapse rate from the surface temperature image produced by the surface temperature image production department and the digital elevation model obtained from the digital elevation model acquisition department. It can be obtained.

According to an embodiment of the present invention, the surface temperature lapse rate estimation unit estimates the surface temperature lapse rate using the surface temperature and altitude information samples selected by the sample data selection unit.

According to an embodiment of the present invention, the altitude effect reduction unit can reduce the altitude effect that appears in the surface temperature image produced by the surface temperature image production unit using the surface temperature lapse rate estimated by the surface temperature lapse rate estimation unit.

According to the present invention, it is possible to estimate the ground temperature lapse rate corresponding to the image shooting time from the ground temperature image provided in the geostationary infrared image.

The present invention has the effect of being able to estimate the global surface temperature lapse rate corresponding to the image shooting time from the global surface temperature image that can be provided by geostationary infrared images.

The present invention has the effect of reducing the influence of terrain altitude that appears on the surface temperature image that can be provided from a geostationary infrared image by using the surface temperature lapse rate.

The present invention has the effect of reducing the influence of terrain altitude on surface temperature images and can be applied to fields such as forest fire detection and volcanic eruption monitoring.

The present invention has the effect of improving the performance of algorithms utilizing surface temperature images, such as forest fire detection and volcanic eruption monitoring, by reducing the influence of terrain altitude that appears in surface temperature images.

The present invention is a technology that can be generally used in various fields of observing surface temperature information, and has effects that can be applied to the civilian field, including the military field, such as image classification, target detection, vegetation monitoring, and object recognition including soil moisture extraction. there is.

Among foreign commercial satellite image processing software, there is a lack of examples of altitude effect reduction techniques for geostationary infrared satellite images being installed as software modules, so the original technology of the present invention can be installed in satellite image processing software developed domestically. Therefore, the present invention has the effect of contributing to increasing the use of satellite images and expanding the national satellite industry through commercialization of the original technology.

The present invention can be applied to domestic geostationary satellites, including communication ocean meteorological satellites and next-generation geostationary meteorological satellites capable of acquiring infrared images, and has the effect of maximizing the utilization of domestic satellite image data.

The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below. will be.

Figure 1 is a diagram showing the configuration of an altitude effect reduction device in geostationary infrared images.
Figure 2 is a diagram showing an example of a geostationary satellite image and a digital elevation model.
Figure 3 is a diagram showing an example of a surface temperature image.
Figure 4 is a diagram showing an example of a method for selecting sample data.
Figure 5 is a diagram showing an example of the estimated surface temperature lapse rate.
Figure 6 is an image showing an example before and after altitude effect correction.
Figure 7 is a diagram showing an example of the use of surface temperature images.
Figure 8 is a flowchart of a method for reducing altitude effects in geostationary infrared images.

Terms or words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it is.

Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, so at the time of filing this application, various alternatives are available to replace them. It should be understood that equivalents and variations may exist.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are intended to indicate the presence of one or more other It should be understood that this does not exclude in advance the presence or addition of features, numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. In describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted. Additionally, in describing embodiments of the present invention, specific numbers are merely examples.

The present invention relates to a method and device for reducing altitude effects in geostationary infrared images. More specifically, the surface temperature image is estimated based on the infrared channel image captured from a satellite operating in geostationary orbit, and the altitude effect on the geostationary infrared image is used to minimize the effect of altitude changes shown in the estimated surface temperature image. It relates to reduction methods and devices.

The invention will be described below in the order of the drawings.

Figure 1 is a diagram showing the configuration of an altitude effect reduction device in geostationary infrared images.

At this time, Figures 2 to 7 are diagrams showing embodiments of image processing according to the present invention's apparatus and method for reducing altitude effects in geostationary infrared images. If the embodiment of FIGS. 2 to 7 corresponds to an embodiment of the corresponding configuration of the device of FIG. 1, the configuration of the device of FIG. 1 will be described with reference to FIGS. 2 to 7.

Referring to Figure 1, the method and device for reducing altitude effects in geostationary infrared images of the present invention include a geostationary satellite image acquisition unit 110, a digital elevation model acquisition unit 120, a cloud area removal unit 130, It includes a surface temperature image production unit 140, a sample data selection unit 150, a surface temperature lapse rate estimation unit 160, and an altitude effect reduction unit 170.

The geostationary satellite image acquisition unit 110 acquires geostationary satellite images taken from a geostationary satellite system. More specifically, the geostationary satellite image acquisition unit 110 is a part that acquires satellite images taken from a geostationary satellite system. In general, geostationary satellite systems, unlike polar orbit satellite systems, have small spatial resolution because they observe the Earth's surface from a very high altitude of 35,786 km.

On the other hand, geostationary satellite systems have the advantage of being able to collect radiant energy in various wavelength bands. Channel images provided by most geostationary satellite systems range from visible wavelengths to near-infrared, mid-infrared, and thermal-infrared wavelengths. Among these, mid-infrared and thermal infrared channel images are recorded by sensors and stored as images of radiant energy emitted from the surface. The geostationary satellite image acquisition unit 110 acquires geostationary channel images of various wavelength bands, including infrared channel images, which are the target of the present invention.

In the field to which the present invention pertains, infrared images refer to images related to radiant energy emitted from the ground, such as mid-infrared rays and thermal infrared rays. Since infrared imaging has the advantage of being able to obtain surface temperature information from the radiant energy emitted from the surface recorded in infrared imagery, it has the advantage of being able to be used for monitoring volcanic activity, forest fires, and urban heat island phenomenon, which require temperature information on the Earth's surface. do.

At this time, in order to perform time series monitoring using a geostationary satellite system that can acquire images in near real time, it is effective to reduce the impact that may occur depending on the shooting time and regional characteristics. In general, regional influences that appear in infrared images include the influence of latitude changes, the influence of topographic slope changes, and the influence of topographic altitude. This is because surface radiation energy is emitted differently depending on latitude, slope, and altitude. Among these, the biggest regional characteristic that appears in infrared channel images is the radiant energy emitted from the ground, which varies depending on terrain altitude. In other words, the surface radiant energy in lowlands and the surface radiant energy in highlands appear differently even at the same latitude and slope. As the altitude increases, the amount of radiant energy emitted from the surface decreases, resulting in a lower surface temperature. At the top of a mountain at a very high altitude, the surface temperature is very low, causing a natural phenomenon in which snow that falls in winter does not melt easily. do.

The digital elevation model acquisition unit 120 acquires a digital elevation model having the same coordinate system as the geostationary satellite image. More specifically, the digital elevation model acquired from the digital elevation model acquisition unit 120 is an image representing height information about the ground surface, and the digital elevation model acquisition unit 120 obtains from the geostationary satellite image acquisition unit 110. Obtain a digital elevation model with the same coordinate system as the geostationary satellite image.

At this time, the digital elevation model acquired by the digital elevation model acquisition unit 120 must have the same coordinate system as the geostationary satellite image acquired by the geostationary satellite image acquisition unit 110, and the spatial resolution must also be similar to that of the geostationary satellite image acquisition unit 110. It is desirable to use a digital elevation model with the same spatial resolution.

If the acquired digital elevation model has a different coordinate system from the acquired geostationary satellite image, it must be converted to have the same coordinate system through coordinate transformation. Additionally, if the obtained digital elevation model has a different spatial resolution from the acquired geostationary satellite image, the digital elevation model must be converted to have the same spatial resolution using an interpolation technique. Coordinate transformation and interpolation techniques can use existing technologies.

Figure 2 is a diagram showing an example of a geostationary satellite image and a digital elevation model.

More specifically, Figure 2 shows an example of a geostationary satellite image acquired by the geostationary satellite image acquisition unit 110 and a digital elevation model acquired by the digital elevation model acquisition unit 120 in an embodiment of the present invention. will be.

Here, Figure 2 (a) shows a geostationary satellite image taken from the HIMAWARI-8 satellite, and Figure 2 (b) is a digital elevation model with the same coordinate system and spatial resolution as the geostationary satellite image.

According to Figure 2 (a), the entire Earth is represented by a geostationary satellite image.

At this time, because the entire Earth is imaged, one of the biggest characteristics of geostationary satellite images is that some areas show day time and some areas show night time depending on the relationship between the sun and the Earth. Since images in the visible light wavelength band can be acquired only during daytime hours and images in the infrared wavelength band can be acquired without influence day or night, Figure 2 (a) well explains the characteristics of geostationary satellite images. there is.

Figure 2(b) is a digital elevation model created from SRTM DEM. In Figure 2(b), coordinate transformation was performed to provide surface elevation information for the same area as the HIMAWARI-8 satellite image, and an interpolation technique was applied to have the same spatial resolution.

The cloud area removal unit 130 uses the satellite image acquired by the geostationary satellite image acquisition unit 110 to detect and remove cloud areas present in the image. The cloud area removal unit 130 can detect and remove cloud areas that may affect surface temperature lapse rate estimation and altitude effect reduction. To explain in more detail, the cloud area removal unit 130 is designed to remove cloud areas, so it can freely remove cloud areas at the user's discretion, and removes cloud areas using cloud area detection techniques developed to date. You may.

Most cloud area detection techniques developed to date perform detection using characteristics of cloud areas. Cloud areas have the characteristics of having very high reflectivity information and very low surface temperature information. Using these characteristics, techniques have been developed to remove cloud areas using reflectivity information from visible light images only in the daytime area, and to remove cloud areas using surface temperature information from infrared images only in the night area. Recently, techniques have been developed to remove cloud areas using various information such as image recording time, satellite sensor shooting angle, and solar zenith angle, in addition to reflectivity information from visible light images and surface temperature information from infrared images. Therefore, it is preferable that the cloud area removal unit 130 removes the cloud area by applying the cloud detection technique developed to date rather than the user directly removing the cloud area. This method of detecting and removing cloud areas can use existing technologies.

The surface temperature image production unit 140 produces a surface temperature image using the infrared satellite image acquired by the geostationary satellite image acquisition unit 110. To explain in more detail, the surface temperature image production unit 140 converts the surface emission radiant energy obtained from the geostationary satellite image acquisition unit 110 into surface temperature.

The commonly used conversion method is the radiative transfer equation (RTE) based on Planck’s function. The Earth Radiation Model equation based on the Planck function converts the surface emission radiant energy into surface temperature information using the wavelength band information of radiant energy, atmospheric upward and downward radiation amount, atmospheric transmittance information, and Planck coefficient. Since each coefficient is provided during the sensor calibration process, the infrared image can be converted into a surface temperature image using each coefficient. This method of producing surface temperature images can use existing technologies.

Meanwhile, Figure 3 is a diagram showing an example of a surface temperature image.

More specifically, Figure 3 shows an example of a ground temperature image produced by the ground temperature image production unit 140 as an embodiment of the present invention.

Figure 3 is an example of a surface temperature image at 6-hour intervals from 0:00 to 18:00 International Standard Time on May 6, 2017. Figure 3 (a) is 0:00 International Standard Time on May 6, 2017, Figure 3 (b) is 6:00 International Standard Time on May 6, 2017, and Figure 3 (c) is May 6, 2017. 12:00 International Standard Time, (d) in Figure 3 is the surface temperature image at 18:00 International Standard Time on May 6, 2017. According to Figure 3, the produced surface temperature image uses the absolute temperature unit as the unit of pixel value. These surface temperature images provide various information depending on the image recording time and characteristics of the surface.

According to Figure 3, most of the surface of the Australian continent, located in the southern hemisphere, consists of desert, so the surface temperature varies greatly over time, while the ocean area shows a small surface temperature deviation due to its high specific heat. Additionally, very low surface temperatures are observed in cloud areas and high altitude areas such as the Himalayas. Therefore, through Figure 3, it can be seen that removal of cloud areas is necessary when estimating the surface temperature lapse rate.

The sample data selection unit 150 provides sample surface temperature and altitude information for estimating the surface temperature lapse rate from the surface temperature image produced by the surface temperature image production unit 140 and the digital elevation model acquired by the digital elevation model acquisition unit 120. obtain.

To explain in more detail, the sample data selection unit 150 acquires surface temperature information and surface altitude information at the same location. Surface temperature information at the same location is obtained from a surface temperature image, and surface elevation information is obtained from a digital elevation model. Here, the same position means the same position coordinates in the image coordinate system. For example, the meaning of the (400,500) position in image coordinates is the 400th position in the line direction (vertical direction) and the 500th position in the pixel direction (horizontal direction), with the upper left corner of the image as the origin (0,0). it means. In other words, when the location information is set to (400,500), the sample data contains the pixel value (surface temperature) corresponding to the (400,500) location in the surface temperature image and the pixel value (surface altitude) corresponding to (400,500) in the digital elevation model. it means.

To explain in more detail, the sample data selection unit 150 acquires sample data on surface temperature and surface altitude suitable for estimating the surface temperature lapse rate. Here, the meaning of the surface temperature lapse rate is the ratio of the surface temperature that decreases when the altitude increases, so it is appropriate to select sample data that clearly shows the surface temperature lapse rate. In other words, suitable sample data for estimating the surface temperature lapse rate are areas with various changes in altitude, and mountainous areas are typically suitable.

To explain in more detail, the sample data selection unit 150 acquires sample data on surface temperature and surface altitude for estimating the surface temperature lapse rate based on mountainous areas. Here, the sample data is not simply to obtain surface temperature information and surface altitude information, but it is appropriate to obtain ‘difference’ information in surface temperature and ‘difference’ information in surface altitude. Since the surface temperature lapse rate is defined as the ratio of the surface temperature that changes as the altitude changes, it is more appropriate to use relative information about the surface temperature and surface altitude rather than using absolute information about the surface temperature and surface altitude. This applies to the method of estimating .

For this purpose, one reference point is selected, a target point is selected within the area surrounding the reference point, and the relative altitude difference information and relative surface temperature difference information of the selected pair (reference point and target point) are obtained and used as sample data. It is desirable to select At this time, if the location difference between the selected pair is small, the difference between the altitude difference and the surface temperature also appears very small, so if the location difference is small, it is desirable to select the target point again. Additionally, if either the reference point or the target point exists within the cloud area, it must be excluded from the sample data.

To explain in more detail, the sample data selection unit 150 acquires a large amount of sample data on surface temperature and surface altitude to estimate the surface temperature lapse rate based on mountainous areas. By selecting multiple target points from one reference point, a large amount of altitude difference and surface temperature difference samples can be obtained.

For example, by selecting 100 target points per reference point, altitude difference and surface temperature difference information for 100 pairs can be obtained. If the reference point is a total of 100 points, the number of sample data for estimating the surface temperature lapse rate is 10,000 data. In order to estimate the global surface temperature lapse rate, it is desirable to secure sample data of more than 5,000 points from about 500 or more reference points.

Meanwhile, Figure 4 is a diagram showing an example of a method for selecting sample data.

More specifically, Figure 4 shows an example of a sample data selection method of the sample data selection unit 150 according to an embodiment of the present invention.

Here, Figure 4(a) shows a method of selecting the reference point 410 as part of the digital elevation model, and Figure 4(b) shows an enlarged view of the red box area 420 in Figure 4(a). This shows a method of selecting the target point 440.

According to (a) of FIG. 4, the reference points 410 for estimating the surface temperature lapse rate are expressed as white dots, and it can be confirmed that they are located in a mountainous area where surface altitude changes are severe on the digital elevation model. According to (b) of Figure 4, the target points 440 expressed as red dots were selected within the target points area 450, and the target points area 450 area is represented in the drawing as a red box. . Target points area 450 refers to an area a certain distance away from the reference point 430, and a target point 440 can be selected within the area.

The surface temperature lapse rate estimation unit 160 estimates the surface temperature lapse rate using the surface temperature and altitude information samples selected by the sample data selection unit 150. At this time, the surface temperature lapse rate estimation unit 160 estimates the global surface temperature lapse rate using the surface temperature difference and altitude difference information of the samples obtained from the sample data selection unit 150. The surface temperature lapse rate estimation unit 160 performs linear regression analysis using a large amount of sample data.

To explain in more detail, the surface temperature lapse rate estimation unit 160 calculates the surface temperature lapse rate through Equation 1 below: Estimate .

At this time, means the surface temperature in the sample data, represents the surface altitude in the sample data, represents the surface temperature lapse rate that can explain the relationship between surface altitude and surface temperature.

According to Equation 1 above, as an independent variable, It is the same as the linear regression model passing through the origin with as the independent variable. In other words, estimating the surface temperature lapse rate is the same as the method of estimating the slope in a linear regression model passing through the origin, and the slope at which the sum of squares of the residuals is minimum can be defined as the surface temperature lapse rate.

Figure 5 is a diagram showing an example of the estimated surface temperature lapse rate.

More specifically, Figure 5 is an example of the surface temperature lapse rate estimated through the surface temperature lapse rate estimation unit 160. Figure 5 shows the surface temperature lapse rate estimated from mid-infrared and thermal infrared surface temperature images taken at 18:00 on May 6, 2017. Figure 5(a) shows the surface temperature lapse rate estimated from the mid-infrared surface temperature image, and Figure 5(b) shows the surface temperature lapse rate estimated from the thermal infrared surface temperature image. As can be seen in Figure 5, the surface temperature lapse rate can be estimated from mid-infrared and thermal infrared surface temperature images, respectively.

In Figure 5, the x-axis of the graph represents altitude difference information in the sample data, and the y-axis represents surface temperature difference information in the sample data. As can be seen in Figure 5, each sample data shows a very diverse distribution, and the surface temperature lapse rate that can represent the entire Earth is calculated by estimating the slope by applying the optimal linear model between the two variables through Equation 1 above. can be estimated.

According to (a) of Figure 5, in the mid-infrared surface temperature image, it can be seen that the surface temperature changes by 4.21K when the altitude increases by 1 km, and according to (b) of Figure 5, in the thermal infrared surface temperature image, the altitude increases by 1 km. You can see that the surface temperature changes by 3.26K.

The altitude effect reduction unit 170 uses the surface temperature lapse rate estimated by the surface temperature lapse rate estimation unit 160 to reduce the altitude effect that appears in the surface temperature image produced by the surface temperature image production unit 140.

To explain in more detail, the altitude effect reduction unit 170 applies the estimated surface temperature lapse rate to the original surface temperature image to obtain a surface temperature image with reduced altitude influence. By reducing the influence of altitude, low surface temperatures in highlands have the effect of increasing, and high surface temperatures in lowlands have the effect of decreasing.

To explain in more detail, the altitude influence reduction unit 170 is a surface temperature image with altitude influence reduced through Equation 2 below: obtain.

At this time, represents the surface temperature image with reduced altitude influence, and represents the image coordinates of the line direction and pixel direction, respectively. represents the surface temperature image produced by the surface temperature image production department, represents the digital elevation model obtained from the digital elevation model acquisition unit. represents the surface temperature lapse rate estimated by the surface temperature lapse rate estimation unit, means the reference altitude. Here, the reference altitude can be freely set by the user.

if If the value is 0, the surface temperature image with reduced altitude effect represents the surface temperature image at an altitude of 0 m above sea level. On the other hand If the value is 500, the surface temperature image with reduced altitude effect represents the surface temperature image at an altitude of 500m above sea level.

Meanwhile, Figure 6 is an image showing an example before and after altitude effect correction.

Figure 6 is a surface temperature image produced from a mid-infrared channel image, and Figure 6 reduces the altitude effect in the surface temperature image at 18:00 on May 6, 2017 using the surface temperature lapse rate in Figure 5.

Figure 6(a) shows the surface temperature image before altitude impact reduction, and Figure 6(b) shows the surface temperature image after altitude impact reduction. According to (a) of Figure 6, it can be seen that Baekdu Mountain and the Gaema Plateau area 610 in the northern part of the Korean Peninsula exhibit low surface temperatures. In addition, it can be seen that the area near Seoraksan Mountain in Gangwon-do (620) also shows low surface temperatures. These areas are mountainous areas with high altitudes and therefore have low surface temperatures. At this time, it can be seen that the altitude of the Baekdu Mountain area is higher than that of Gangwon-do, so the surface temperature is lower. Figure 6(b) is a surface temperature image in which the altitude effect on the surface temperature image was reduced using the estimated surface temperature lapse rate of 4.21K/km.

When comparing Figure 6 (a) and Figure 6 (b), it can be seen that as a result of reducing the influence of altitude, the surface temperature in the highland area increases and has information similar to that of the surrounding area. In particular, the area around Mt. Baekdu and Gaema Plateau in the northern part of the Korean Peninsula in Figure 6 (a) and the area around Mt. Seorak in Gangwon-do (620) and the area around Mt. Baekdu and Gaema Plateau in the northern part of the Korean Peninsula in Figure 6 (b) and around Mt. Seorak in Gangwon-do (630). When comparing 640), it can be seen that the surface temperature (630) in the Baekdu Mountain and Gaema Plateau area in the northern part of the Korean Peninsula has increased further and has a surface temperature similar to that in the Gangwon-do area (640).

Meanwhile, Figure 7 is a diagram showing an example of the use of a surface temperature image.

More specifically, Figure 7 is an enlarged image before and after altitude effect correction, showing an example of improved forest fire detection possibility, which is one of the areas of use of surface temperature images. Figure 7 is a surface temperature image near Samcheok, Gangwon-do at 18:00 on May 6, 2017.

Figure 7(a) shows before the altitude impact is reduced, and Figure 7(b) shows after the altitude impact is reduced. According to Figure 7, the pixels (710, 730) displayed in yellow in the center of the image show a very high surface temperature of about 300K even though it is 3 a.m. local time, and while the image was being filmed, a forest fire actually broke out in Samcheok, Gangwon-do. Since it occurred, it is very likely that it was a forest fire. Most forest fire detection techniques use surface temperature information of pixels surrounding a forest fire suspicious pixel to determine whether a suspicious pixel is a forest fire pixel, and as key indicators, the difference in surface temperature between the suspected forest fire pixel and surrounding pixels and the volatility of the surface temperatures of surrounding pixels are used as key indicators. Use . At this time, as the volatility of surrounding pixels decreases, the possibility of identifying a suspected forest fire pixel as a forest fire pixel improves.

When comparing (a) of FIG. 7 with (b) of FIG. 7, the index of the surrounding pixels of FIG. 7 (b) has a reduced altitude effect compared to the surface temperature 720 of the surrounding pixels of FIG. 7 (a). It can be confirmed that the temperature 740 has a more uniform surface temperature. Therefore, the possibility of forest fire detection can be improved by reducing the altitude effect through the present invention.

The method and device for reducing altitude effects in geostationary infrared images according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., singly or in combination. Program instructions recorded on the medium may be specially designed and constructed for the present invention or may be known and usable by those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, and ROM and RAM. It includes specially configured hardware devices to store and perform programs audfudd, such as flash memory, etc. Examples of program instructions include machine language code, such as that produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

Figure 8 is a flowchart of a method for reducing altitude effects in geostationary infrared images.

First, geostationary satellite images and digital elevation models with the same coordinate system and resolution are acquired (S810). Then, the cloud area appearing in the geostationary satellite image is removed (S820). A surface temperature image is produced from the infrared image (S830), and sample data for estimating the surface temperature lapse rate is constructed by acquiring surface temperature information and altitude information at the same location (S840). Using the surface temperature information and altitude information constructed as sample data, the surface temperature lapse rate at the video shooting time is estimated (S850). Lastly, the altitude effect appearing in infrared satellite images can be reduced (S860) using the estimated surface temperature lapse rate.

As described above, the present invention has been described with specific details such as specific components and limited embodiments and drawings, but this is only provided to facilitate a more general understanding of the present invention, and the present invention is not limited to the above embodiments. , those skilled in the art can make various modifications and variations from this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and the scope of the patent claims described below as well as all modifications that are equivalent or equivalent to the scope of this patent claim shall fall within the scope of the spirit of the present invention. .

110: Geostationary satellite image acquisition unit
120: Digital elevation model acquisition unit
130: Cloud area removal unit
140: Surface temperature image production department
150: Sample data selection unit
160: Surface temperature lapse rate estimation unit
170: Altitude impact reduction unit

Claims (10)

In the altitude effect reduction device using geostationary infrared imaging,
A surface temperature image production department that generates a surface temperature image based on the acquired geostationary infrared image;
a sample data selection unit that acquires surface temperature information and altitude information of a sample based on a digital elevation model of the surface temperature image and the geostationary infrared image;
a surface temperature lapse rate estimation unit that estimates a surface temperature lapse rate using the surface temperature information and the altitude information of the sample; and
It includes an altitude effect reduction unit that reduces the altitude effect that appears in the generated surface temperature image based on the estimated surface temperature lapse rate,
The sample includes a reference point and a target point on the geostationary infrared image based on a mountainous area,
The surface temperature information includes a surface temperature difference between the reference point and the target point of the sample,
The altitude information includes an altitude difference between the reference point and the target point of the sample,
The surface temperature lapse rate is estimated through linear regression analysis using the surface temperature information and the altitude information of the sample. delete delete delete According to claim 1,
An altitude impact reduction device that performs at least one of forest fire detection, volcanic eruption monitoring, and urban heat island phenomenon monitoring based on the surface temperature image with the altitude impact reduced.
According to claim 1,
The geostationary infrared image is,
An altitude effect reduction device, which is an image from which cloud areas have been removed using cloud detection techniques.
delete According to claim 1,
The digital elevation model is,
An altitude effect reduction device having the same coordinate system and the same spatial resolution as the geostationary infrared image.
In the altitude effect reduction method using geostationary infrared imaging,
Generating a surface temperature image based on the acquired geostationary infrared image;
Obtaining surface temperature information and altitude information of a sample based on a digital elevation model of the surface temperature image and the geostationary infrared image;
estimating a surface temperature lapse rate using the surface temperature information and the altitude information of the sample; and
Reducing the altitude effect appearing in the generated surface temperature image based on the estimated surface temperature lapse rate,
The sample includes a reference point and a target point on the geostationary infrared image based on a mountainous area,
The surface temperature information includes a surface temperature difference between the reference point and the target point of the sample,
The altitude information includes an altitude difference between the reference point and the target point of the sample,
A method for reducing altitude influence, wherein the surface temperature lapse rate is estimated through linear regression analysis using the surface temperature information and the altitude information of the sample.
In a computer program stored on a non-transitory computer readable medium,
On your computer,
Generating a surface temperature image based on the acquired geostationary infrared image;
Obtaining surface temperature information and altitude information of a sample based on a digital elevation model of the surface temperature image and the geostationary infrared image;
estimating a surface temperature lapse rate using the surface temperature information and the altitude information of the sample; and
Reducing the altitude effect appearing in the generated surface temperature image based on the estimated surface temperature lapse rate; executing,
The sample includes a reference point and a target point on the geostationary infrared image based on a mountainous area,
The surface temperature information includes a surface temperature difference between the reference point and the target point of the sample,
The altitude information includes an altitude difference between the reference point and the target point of the sample,
The surface temperature lapse rate is estimated through linear regression analysis using the surface temperature information and the altitude information of the sample, a computer program stored in the medium.

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