JP2018151775A - Physical quantity distribution map creation method and physical quantity distribution map creation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a prior art has, specifically to provide a physical quantity distribution map creation method and a physical quantity distribution map creation device that can prepare a physical quantity distribution map without positioning actively such as the GNSS positioning.SOLUTION: A physical quantity distribution map creation method according to the present invention is a method for preparing a physical quantity distribution map comprising a travelling measurement process, a physical quantity setting process, ortho-image preparation process, and a distribution map preparation process. The physical quantity setting process adds a representative physical quantity to each ground image based on a physical quantity obtained by the travelling measurement process. The ortho-image preparation process prepares an ortho-image of a subject range based on a plurality of ground images. Then, the distribution map preparation process prepares a physical quantity distribution map by displaying the representative image on the ortho-image.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technique for creating a physical quantity distribution map such as a radiation dose rate in a target region, and more specifically, a physical quantity distribution map can be created without requiring special positioning means. The present invention relates to a method and apparatus.

  In recent years, environmental destruction caused by global warming has progressed, and the preservation of the global environment has become a global problem. In 1997, the Kyoto Protocol was signed, and many countries are actively tackling this issue, including the establishment of greenhouse gas reduction targets. In Japan as well, measures to reduce greenhouse gases have been implemented by public and private sectors, one of which is nuclear power generation. In addition to the power generated by nuclear power generation, the amount of greenhouse gas emissions is much smaller than that of so-called fossil energy generation, so a shift from the previous power generation method to this method has been made.

  On the other hand, Japan is known as a country where earthquakes occur frequently, and major earthquakes such as the Tohoku-Pacific Ocean Earthquake, the Hyogoken-Nanbu Earthquake, and the Niigata-ken Chuetsu Earthquake have occurred and have suffered enormous damage each time. In the previous Great East Japan Earthquake, there was an accident in which a large amount of radioactive material leaked due to the damage caused by the tsunami and further damage to the reactor at the Fukushima nuclear power plant.

  The radioactive material leaked from the nuclear power plant spread not only in the vicinity but also in a wide area. This is thought to be due to the radioactive substance adhering to the aerosol or the like, and the aerosol or the like becomes a transporter that entrains the radioactive substance far away and descends to the ground due to rainwater or the like. In any case, the effects of accidents at nuclear power plants are wide-ranging, and the Special Measures Act on Radioactive Substance Contamination Measures Concerning the Environmental Pollution Status of Accident-derived Radioactive Substances More than 100 municipalities are designated as “Region”.

  Even if radioactive materials are diffused over a wide area, the radiation dose varies depending on the location, and some regions show extremely high radiation doses, while others show radiation doses that do not affect the environment. In areas with high radiation doses, the effects on the human body must be considered. Each residential area is restricted using the annual radiation dose (mSv / year) as an index. 50mSv or more is a difficult return home area, 20mSv or more is a residential restriction area, and 1mSv or more is an evacuation order cancellation preparation area. Several municipalities still apply. It is an urgent issue to take appropriate decontamination measures for such restricted areas and to release all restrictions at an early stage.

  By the way, although the whole area does not show a very high radiation dose, there are cases where it shows a very high radiation dose locally. Or the case where a low radiation dose is partially shown even if it is a residence restriction area is also considered. It is extremely important for life safety to extract a spot that shows a high radiation dose locally compared to the surrounding area (hereinafter referred to as “hot spot”). Extraction of the point indicating the dose occurs in a situation where the decontamination work is reduced and there are not enough places to store the contaminated soil generated by the decontamination (such as temporary storage and intermediate storage facilities). As a result, the amount of contaminated soil is reduced, which is extremely beneficial.

  As described above, when the local radiation dose is grasped, a method is used in which partial measurement is performed by dividing into a narrow range, not the entire measurement by an aircraft or the like. In fact, in Fukushima Prefecture, more than 200,000 houses are surveyed one by one, and decontamination measures are being promoted according to the results. When measuring the radiation dose of a house, follow the “Guidelines for Handling Locally Contaminated Sites with Radioactive Substances—Ministry of the Environment” (hereinafter simply referred to as “Guidelines for Handling Contaminated Sites”). After extracting a predicted part (hereinafter referred to as “contamination predicted part”), the measurement is performed mainly on the part. This is to find “locally contaminated spots” that are actually contaminated as soon as possible, and examples of the predicted rain spots include rain gutters, drain outlets, gutters / drains, and rain gutters of buildings.

  However, the extraction of the predicted contamination location is performed by human judgment, and the extraction accuracy depends on the knowledge and experience of the investigator. Considering a large number of research houses, a large number of investigators will make measurements, and therefore, the extraction criteria for the predicted contamination location will be uneven, and as a result, the localized contamination location may not be found correctly. In addition, if the measurement results are not recorded together with the position information, appropriate decontamination measures cannot be implemented. However, while measuring the radiation dose, the position measurement is performed at the same time, and the measurement value and the position information are recorded in association with each other. It is not so easy to do. Actually, the actual measurement position is written on the prepared paper drawing, and as a result, an error or a record omission may occur, but this cannot be confirmed later.

  When investigating the radiation dose for the outdoors, it is conceivable to use a satellite positioning system (GNSS: Global Navigation Satellite System) to record the measurement value and the positional information in association with each other. By measuring the position coordinates of the survey point with GNSS, the measurement value and the position information can be recorded as a set. However, it is known that an error of about 10 m is caused by independent positioning by GNSS, and when there is a fault such as a roof or a garden tree, a point greatly deviated from the site may be output as coordinates.

  Therefore, Patent Document 1 proposes a radiation distribution measurement technique using both positioning by GNSS and positioning by autonomous navigation. According to this technology, it is possible to record the measurement value and the positional information in association with each other while improving the positioning accuracy by correcting using the results of the GNSS positioning and the autonomous navigation positioning.

Japanese Patent Application Laid-Open No. 2015-175803

  According to the technique of Patent Document 1, since two types of positioning are used in combination, it is possible to acquire position coordinates with higher accuracy than the result of only GNSS positioning, but it is known that errors are accumulated in autonomous navigation positioning. In addition, since single positioning by GNSS may cause a large error as described above, it may be impossible to acquire highly accurate position coordinates at some measurement points in the case of positioning a multipoint number. Moreover, when surveying both outdoors and indoors, since GNSS positioning cannot be used indoors, it also takes time to replace the positioning means used outdoors and indoors.

  Therefore, the inventors of the present invention have not determined the location of the measurement point without actively positioning like GNSS positioning in grasping the distribution of the physical quantity within the range to be investigated (hereinafter referred to as “target range”). An object of the present invention is to provide a technique capable of creating a physical quantity distribution map (hereinafter referred to as a “physical quantity distribution chart”) by associating a physical quantity with position information. Here, “physical quantity” means any attribute that shows different values depending on the location, such as radiation dose rate, geomagnetism, temperature, and various gas concentrations.

  In order to solve the above-mentioned problems, the inventors of the present invention decided to create an orthographic image of a target range from a plurality of images obtained by copying the ground (outdoor ground surface, indoor floor surface, etc.). Usually, in order to create an orthographic image from only an image, a large number of overlapping images are required, and therefore image acquisition means (camera, video camera, etc.) that can be photographed at high speed (for example, 30 fps) are used. As a result, a large amount of images are acquired, that is, an orthographic image is created using a large amount (more than necessary) of images, and the creation (analysis) takes considerable time and cost. . Accordingly, providing a technique capable of reducing the creation time and cost when creating an orthographic image from only the image is also an object of the present invention.

  As described so far, the subject of the present invention is to solve the problems of the prior art, that is, a physical quantity distribution diagram that can create a physical quantity distribution chart without actively positioning like GNSS positioning. And a physical quantity distribution map creating apparatus. It is also an object of the present invention to provide a technique capable of reducing the orthographic image creation time and cost.

  The present invention focuses on creating an orthographic image of a target range from a ground image acquired while moving, and creating a physical quantity distribution map by assigning a physical quantity to the ground image. It is an invention made based on an idea that did not exist.

  The physical quantity distribution map creation method of the present invention is a method of creating a physical quantity distribution map of a target range, and includes a movement measurement process, a physical quantity setting process, an orthographic image creation process, and a distribution map creation process. In the movement measurement step, while moving the target range, the ground is imaged so that adjacent images overlap to obtain a plurality of ground images, and a physical quantity is measured. In the physical quantity setting step, a representative physical quantity is assigned to each ground image based on the physical quantity obtained in the movement measurement process. In the orthographic image creation step, an orthographic image of the target range is created based on a plurality of ground images. In the distribution map creation step, the physical quantity distribution map is created by displaying the representative physical quantity on the orthographic image.

  The physical quantity distribution map creation method of the present invention can be a method of measuring a radiation dose rate as a physical quantity. In this case, a representative radiation dose rate is given to the ground image in the physical quantity setting step, and the representative radiation dose rate is displayed on the orthographic image in the distribution map creation step.

  The physical quantity distribution map creation method of the present invention may be a method of creating a physical quantity distribution map using a part of the acquired ground image. In this case, in the movement measurement step, it is determined whether or not the ground image is used for creating the orthographic image based on the speed of moving the target range, and in the physical quantity setting step, it is determined that the ground image is used for creating the orthographic image. A representative physical quantity is assigned to the ground image (hereinafter referred to as “use ground image”), and in the orthographic image creation step, an orthographic image of the target range is created based on the use ground image. Further, based on the degree of overlapping of adjacent images instead of the moving speed, it can also be determined whether or not the ground image is used for creating an orthogonal image. The degree of overlapping of adjacent images can be obtained based on the movement distance moved in the target range.

  The physical quantity distribution map creation method of the present invention can also be a method of photographing the ground with image acquisition means fixed at a substantially constant height from the ground. In this case, in the orthographic image creation step, the scale of the ground image is obtained based on the distance between the image acquisition means and the ground, and the orthographic image is created using the orthographic image to which this scale is applied.

  The physical quantity distribution map creating method of the present invention may be a method of photographing the ground with an image acquisition unit fixed to a support column and measuring a physical quantity with a measurement unit fixed to the support column.

  The physical quantity distribution map creation method of the present invention can be a method further comprising a positioning step of acquiring planar coordinates of two or more points within the target range. In this case, in the orthographic image creation process, an orthographic image in which a predetermined coordinate system is set is created based on the plane coordinates acquired in the positioning process.

  The physical quantity distribution diagram creation device of the present invention is a device that creates a physical quantity distribution diagram of a target range, and includes an image acquisition means, a measurement means, a physical quantity setting means, an orthographic image creation means, and a distribution map creation means. is there. The image acquisition means is fixed at a substantially constant height from the ground, and can acquire a ground image obtained by photographing the ground while moving the target range. The measurement means measures a physical quantity within the target range. is there. Further, the physical quantity setting means gives a representative physical quantity to the ground image based on the physical quantity measured by the measuring means, and the orthographic image creating means is based on a plurality of ground images in which adjacent images overlap. Create an orthographic image of the range. The distribution map creating means creates a physical quantity distribution map by displaying the representative physical quantity on the orthographic image.

  The physical quantity distribution map creating apparatus of the present invention may further include a speed measuring unit, an image selecting unit, and an image storing unit. The speed measuring means acquires a moving speed when moving in the target range. The image sorting means sorts the ground image into either a used ground image or an unused ground image based on the moving speed acquired by the speed measuring means. The image storage means stores only the use ground image selected by the image selection means. The orthographic image creation means in this case creates an orthographic image of the target range based on the ground image used.

The physical quantity distribution map creation method and physical quantity distribution map creation apparatus of the present invention have the following effects.
(1) Since an orthogonal image composed of a plurality of ground images is used, a physical quantity distribution diagram with high positional accuracy (in an arbitrary coordinate system) can be created.
(2) Compared to the conventional method, the time required for completion is reduced, that is, it is completed in a short period of time, so that a physical quantity distribution diagram with high freshness can be created. Moreover, since a physical quantity distribution map can be created in a short period of time, it is possible to plan rough measures (such as decontamination) on site at an early stage.
(3) Since GNSS positioning is not essential, a physical quantity distribution map in which indoors are measured can also be created.

(A) is a model diagram for explaining a ground image acquired with the passage of time, (b) is a model diagram for explaining a physical quantity acquired with the passage of time, and (c) is a model diagram for explaining the passage of time. The model figure explaining the moving speed acquired. The flowchart which shows the flow of the main processes of the preparation method of the physical quantity distribution map of this invention. The model figure which shows the column physical-quantity distribution map creation apparatus of a support column (pole) form. (A) is a model figure explaining the adjacent image overlapped moderately, (b) is a model figure explaining the adjacent image overlapped excessively. The model figure explaining the specification which sets a physical quantity to a ground image. The model figure explaining the specification which extracts a ground image regularly. The model figure explaining the specification which classify | selects a ground image into either a use ground image or a non-use ground image based on a moving speed. The flowchart explaining the specification which classifies a ground image into either a use ground image or a non-use ground image based on a moving speed. ( _A ) is a model diagram showing an image range P _A (n) and an allowable overlapping range L _A (n) of the n-th acquired ground image, and (b) is an allowable overlapping range L _A (n) and other The model figure which compared the image range of the ground image. The block diagram which shows the main structures of the physical quantity distribution map creation apparatus of this invention.

  An example of an embodiment of a physical quantity distribution diagram creation method and a physical quantity distribution diagram creation apparatus according to the present invention will be described with reference to the drawings.

1. Definitions In describing examples of embodiments of the present invention, definitions of main terms used here will be given first.

(Scope)
The range to be surveyed as described above is referred to as “target range” here. For example, the target range includes various areas including the outdoors and indoors, such as a house or school site, or a predetermined range in a facility.

(Ground image)
One feature of the present invention is that an orthographic image (ortho image) is used as a plan view (so-called base diagram) serving as a basis for representing the measurement position of the measured physical quantity. This orthographic image is obtained by photographing a substantially horizontal plane representing a plane position, and “substantially horizontal plane” is defined as “ground” here. Accordingly, examples of the ground include an outdoor ground surface, a water surface, and an indoor floor surface. An image obtained by photographing the ground is herein referred to as a “ground image”.

In the present invention, the ground image is acquired periodically (for example, at intervals of 1/30 seconds), intermittently, or continuously while the investigator (or moving body) moves. That is, after moving, the ground image is sequentially acquired as time passes. FIG. 1A is a model diagram for explaining a ground image acquired as time passes. As shown in this figure, where for distinguishing each ground image, P ₁ on the obtained _forward, P 2, _{P 3,} timing the · · · P _n with a name of each ground image, respectively to get the ground image _Let (timing) be Tp ₁ , Tp ₂ , Tp ₃ ,... Tpn.

(Physical quantity)
As described above, any attribute indicating a value (linked to a position) that varies depending on a location such as a radiation dose rate, geomagnetism, temperature, and various gas concentrations is referred to as a “physical quantity” herein. In the present invention, as with the ground image, the physical quantity is acquired periodically (for example, at intervals of 1 second), intermittently, or continuously while the investigator moves. That is, after moving, the physical quantity is acquired sequentially with time. FIG. 1B is a model diagram illustrating physical quantities that are acquired over time. As shown in this figure, here, in order to distinguish each physical quantity, R ₁ , R ₂ , R ₃ ,... R _n are named as physical quantities in the order of acquisition, and the timing (timing) at which each physical quantity is acquired. Are Tr ₁ , Tr ₂ , Tr ₃ ,... Tr _n .

(Moving Speed)
As will be described later, in order to extract a ground image when creating an orthographic image (in other words, to thin out an extra ground image), it is also possible to measure the speed at which the investigator moves. Here, the moving speed is referred to as “moving speed”. The moving speed is also acquired periodically (for example, at intervals of 1/5 second), intermittently or continuously while the investigator moves. That is, after moving, the moving speed is sequentially acquired as time passes. FIG.1 (c) is a model figure explaining the moving speed acquired with time progress. As shown in this figure, where for distinguishing the moving speed of each, V ₁ to the obtained _order, V 2, _{V 3,} timing the · · · V _n is the name of the moving speed, obtained respectively moving speed _Let (timing) be Tr ₁ , Tr ₂ , Tr ₃ ,... Tr _n .

2. Next, a method for creating a physical quantity distribution diagram of the present invention will be described with reference to FIG. FIG. 2 is a flowchart showing the flow of the main steps of the method for creating a physical quantity distribution diagram of the present invention. In addition, here, for the sake of convenience, the case where the investigator conducts the survey while walking will be described, but the present invention is carried out while moving on a mobile body (car, flying object, robot, etc.) equipped with necessary equipment in addition to the researcher You can also

  As shown in FIG. 2, first, the movement measurement of the target range is performed (Step 100). The movement measurement is a process in which an investigator acquires a ground image while walking (Step 111) and measures a physical quantity (Step 121). Further, the moving speed (that is, walking speed) can be measured while moving (Step 131), and the position coordinates can be measured (GNSS positioning or indoor positioning) while moving. By using GNSS positioning or indoor positioning, by obtaining the plane coordinates of two or more points in the target range, an orthographic image of the target range in which a predetermined coordinate system (for example, the world geodetic system) is set is created. be able to.

  Since the device used for the movement measurement needs to move with the investigator, it is preferable to use an integrated device so that the investigator can easily carry the device. For example, as shown in FIG. 3, it is possible to carry a portable measuring device in which an image acquisition means 111 and a measuring means 121 are fixed to a support pillar 190 (pole), and carry it for investigation. When the portable measuring device shown in this figure is used, the distance from the image acquisition unit 111 to the ground (that is, the height of the image acquisition unit 111) is kept substantially constant, and as a result, the scale of the acquired ground image is obtained. In other words, the scale of the orthographic image created from the ground image can also be grasped. Of course, the portable measuring device is not limited to the support pole (pole) type, but can be in various forms such as a backpack type and a helmet fixing type.

  Only one measuring means 121 can be carried or a plurality of measuring means 121 can be carried. When using a plurality of measuring means 121, it is preferable to change the height (that is, the fixed position) to be measured as shown in FIG. It is also possible to simultaneously measure two or more types of physical quantities (for example, radiation dose rate and gas concentration) while moving two or more types of measuring means 121 on the support column 190 and moving.

  In addition to the image acquisition unit 111 and the measurement unit 121, a speed measurement unit 131 such as an accelerometer or a DMI (Distance Measurement Indicator) and a positioning unit 140 such as a GNSS receiver can be attached to the supporting unit 190. The carrying measurement apparatus shown in FIG. 3 further includes a monitor that displays the ground image and the measured amount of material on the spot, and a backpack that houses control units and batteries of various devices.

  For example, the investigator walks so as to cover the target range with a portable measuring device as shown in FIG. 3, and acquires a ground image and a physical quantity or a moving speed at each point in the target range. Note that the ground image, the physical quantity, and the moving speed are measured periodically, intermittently, continuously, or automatically. However, since the timings of measurement are different, the survey points do not necessarily match.

The ground image and the physical quantity acquired in the movement measurement process, or the moving speed are stored in association with the acquired time each time measurement is performed (that is, in real time). If the ground image associated P _n and Tp _n shown in FIG. 1 (a) (as a set) are stored, also a physical quantity in the case if Fig 1 (b) in the storage associated with it R _m and Tr _m showing If it is a moving speed, V _k and Tv _k shown in FIG. 1C are stored in association with each other.

  When the ground image and the physical quantity can be acquired in the movement measurement process, an orthogonal image is created (Step 200), and the physical quantity is set (Step 300). In the orthographic image creation step (Step 200), a plurality of ground images are synthesized to create an orthographic image of the target range. Specifically, an orthographic image of the target range is created using the SfM (Structure from Motion) technique in which feature points stored between adjacent ground images are combined (matched) and synthesized. Therefore, in the ground image acquisition step (Step 111), as shown in FIG. 4A, the ground image is acquired so that two adjacent images (hereinafter referred to as “adjacent images”) are appropriately overlapped (wrapped). .

In the physical quantity setting step (Step 300), physical quantities are set for the acquired individual ground images. FIG. 5 is a model diagram illustrating specifications for setting a physical quantity in a ground image. As shown in this figure, one physical quantity is set (associated) with each ground image. In this case, the physical quantity R _m which is set on the ground image P _n, the amount of physical acquired by the time closest to the time Tp _n acquired ground image P _n R _m is selected. With reference to FIG. 5, for example, the closest physical quantity acquisition time to the time acquired ground image P ₂ Tp ₂ is Tr _2, therefore a physical quantity R ₂ with respect to the ground image P ₂ is set.

If the time interval for acquiring the ground image is shorter than the acquisition of the physical quantity, the number of ground images is larger than the acquired physical quantity. In this case, as shown in FIG. 5, one physical quantity (R ₃ ) may be set to a plurality of ground images (P ₃ , P ₄ , P ₅ ), or the ground image closest to the time when the physical quantities are acquired. It may be set only to (→). In the case where one physical quantity is set to one ground image, a ground image for which no physical quantity is set can be complemented (interpolated) with a physical quantity set to another ground image. For example, in the case of FIG. 5, the physical quantity R ₃ is set only in the ground image P ₄ , and the physical quantity set in the ground image P ₃ is complemented based on the physical quantity R ₂ and the physical quantity R ₃ and set in the ground image P _5. The physical quantity is supplemented based on the physical quantity R ₃ and the physical quantity R ₄ .

  An orthographic image of the target range is created (Step 200), and when a physical quantity is set for each ground image (Step 300), a physical quantity distribution map is created (Step 400). The physical quantity distribution diagram is a diagram showing the value of the physical quantity at each point with an orthographic image of the target range as a base diagram. Since a physical quantity is set for each ground image constituting the orthographic image of the target range, a physical quantity distribution map can be created. The plane position indicating the physical quantity can be a predetermined specific point such as the image center point of the corresponding ground image.

  By the way, it has been described that the orthographic image of the target range is created by combining the feature points of the overlapping adjacent images. In order to acquire an image while walking (moving) and overlapping adjacent images, an image acquisition means (especially a video camera) capable of shooting at high speed (for example, 30 fps) is used. That is, the photograph is acquired at a high speed (short time interval) with respect to the walking speed, and as a result, a large amount of ground images are acquired and stored. In this case, as shown in FIG. 4B, most of the adjacent images overlap, but it is not necessary to overlap so much to create a composite image.

  Therefore, it is conceivable to use only images that are appropriately extracted (that is, thinned out) instead of using all acquired ground images. For example, as shown in FIG. 6, only the ground image extracted periodically may be stored and used. In this figure, a ground image to be used (hereinafter referred to as “used ground image”) is represented by a black circle, and a ground image not to be used (hereinafter referred to as “unused ground image”) is represented by a white circle, which is obtained six times. In this example, the ground image used is extracted and stored each time. By extracting (thinning out) the ground image used, it is possible to reduce the area for storing the image, and it is possible to reduce the analysis cost when creating an orthographic image.

  Even if the ground images can be periodically reduced, if the investigator's walking speed is extremely reduced or stopped, an overlapping image is obtained as shown in FIG. 4B. End up. Therefore, an extra speed ground image can be eliminated by measuring the moving side as the movement measuring step (Step 131). FIG. 7 is a model diagram for explaining a specification for selecting a ground image to be a used ground image or a non-use ground image based on the moving speed, and FIG. 8 is a flowchart for explaining the specification. Hereinafter, this will be described in detail with reference to FIGS.

  As shown in FIG. 7, the average speed calculation period t is set in a period shorter than the acquisition interval of the used ground image (extraction interval of the extracted image), and the average speed Va during that period is obtained. Then, as shown in FIG. 8, when the average speed is smaller than a preset threshold value, the used ground image acquired next is repositioned as “unused ground image” and discarded and not stored. On the other hand, when the average speed is greater than a preset threshold value, the next-use ground image acquired is stored as it is and used for orthographic image creation. As a result, when the investigator is walking too slowly or stopped, it is preferable not to store an extra image and to reduce the analysis cost when creating an orthographic image. .

The determination of the unused ground image can also be performed based on the degree of overlap between adjacent images. FIG. 9A is a model diagram showing the image range P _A (n) and the allowable overlap range L _A (n) of the n-th acquired ground image, and FIG. 9B is the allowable overlap range L _A (n ) And image ranges P _A (n + 1) and P _A (n + 2) of other ground images. When an image range or an allowable overlap range (or a center point described later) in the nth ground image is indicated, n is indicated in parentheses such as the image range P _A (n) and the allowable overlap range L _A (n). and then, when referring to the image area and the allowable overlap range of common ground image is simply an image range P _a, and is represented by the allowable overlap range L _a.

Image area P _A is a range that is acquired by the image acquisition unit 111, for example, when using a video camera can be determined magnitude and angle of view of the imaging device, a focal length, from the distance to the video camera and the surface . Alternatively, it is also possible to have defined the image area P _A of the image acquisition unit 111 by previously measured. The allowable overlap range L _A is the reference range for determining that an overlapping range required orthoimage synthesis, i.e. orthographic if the center point of adjacent images are in the allowable overlap range L _A picture It can be determined that the degree of overlap is sufficient to create a composition. In should be noted FIG. 9 (a), the circle relative to the center point P _O of the image area P _A is the allowable overlap range L _A but similar shape of the image area P _A is not limited thereto (e.g., rectangular) to such , it is possible to set the allowable overlap range L _a in any shape.

Hereinafter, the specification for determining the used ground image or the unused ground image based on the overlapping degree of the adjacent images will be described with reference to FIG. First, a distance from the position at which the image range P _A (n) is acquired to the position at which the image range P _A (n + 1) is acquired (hereinafter referred to as “movement distance L”) is acquired. At this time, means (apparatus) that can measure the distance while moving may be used. For example, the travel distance L is obtained by using an acceleration sensor that measures acceleration, an autonomous navigation system obtained by combining an acceleration sensor with a gyro that measures an angle, or a DMI that measures distance from the rotation of a wheel (tire). can do. Alternatively, the distance between two points may be obtained by GNSS positioning, and this may be acquired as the movement distance. Note that the movement distance L may be measured as long as a suitable accuracy can be obtained within a time range or a movement distance range in which the degree of overlap of related image ranges can be grasped. It may be much lower than. When the movement distance L is obtained, a center point P _O (n + 1) moved by the movement distance L is calculated from the center point P _O (n) of the image range P _A (n), and this center point P _O (n + 1) is calculated. ) Is in the allowable overlap range L _A (n), it is determined that the overlap is satisfied, and otherwise it is determined that the overlap is insufficient.

In addition, in order to thin out excessively duplicated ground images, if the ground image after the image range P _A (n) is continuously determined to be sufficient, only the ground image immediately before the ground image determined to be insufficiently overlapped is used. The ground image is selected as a ground image, and other ground images determined to be sufficient are discarded as unused ground images. For example, the center point P _O (n + k) of the n + k-th image range P _A (n + k) shown in FIG. 9B is within the image range P _A (n), and the center of the next image range P _A (n + k + 1). Since the point P _O (n + k + 1) is outside the image range P _A (n), in this case, the n + k-th ground image is selected as the use ground image. In this case, even if the ground images between the nth and n + kths have sufficient overlap, these ground images are thinned out to be unused ground images.

3. Physical Quantity Distribution Diagram Creating Device Next, the physical quantity distribution diagram creating device of the present invention will be described with reference to FIG. The physical quantity distribution map creating apparatus of the present invention can be used when the physical quantity distribution map creating method of the present invention is performed, and therefore, the contents described in “2. A duplicate description will be avoided here, and only the contents peculiar to the physical quantity distribution map creation device of the receiver will be described. That is, the contents not described here are the same as those described in “2. Method of creating physical quantity distribution diagram”. Of course, the terms defined in advance are applied in the explanation here as well as in “2. Method of creating physical quantity distribution diagram”.

  FIG. 10 is a block diagram showing the main configuration of the physical quantity distribution map creating apparatus 100 of the present invention. As shown in this figure, the physical quantity distribution map creation device 100 includes an image acquisition means 111, a measurement and measurement means 121, an orthographic image creation means 150, a physical quantity setting means 160, and a distribution map creation means 170. In addition, the image extracting unit 112, the physical quantity storing unit 122, the speed measuring unit 131, the moving speed storing unit 132, the image selecting unit 113, the image storing unit 114, the positioning unit 140, and the output unit 180 may be provided. . In addition, it can be set as the carrying measuring apparatus mentioned above collectively the means enclosed within the broken line shown in this figure.

  The physical quantity acquired by the measuring unit 121 is stored in the physical quantity storage unit 122, and the moving speed acquired by the speed measuring unit 131 is stored in the moving speed storage unit 132. As for the ground image acquired by the image acquiring unit 111, only the used ground image extracted by the image extracting unit 112 is stored in the image storage unit 114 as shown in FIG. Alternatively, only the used ground image selected by the image selecting unit 113 among the used ground images extracted by the image extracting unit 112 can be stored in the image storage unit 114. As shown in FIGS. 7 and 8, the image selecting means 113 is a means for further selecting the selected used ground image into the used ground image or the unused ground image based on the moving speed (by comparing with the threshold value). It is. The positioning means 140 is a means that can measure planar position coordinates such as GNSS positioning and indoor positioning.

  The orthographic image creation means 150 is a means for creating an orthographic image of the target range by reading the use ground image stored in the image storage means 114, and the physical quantity setting means 160 reads the physical quantity from the physical quantity storage means 122. This is means for reading the ground image used and setting the physical quantity (FIG. 5). Then, the distribution map creation means 170 creates a physical quantity distribution image based on the orthographic image of the target range and each use ground image in which the physical quantity is set, and outputs this physical quantity distribution image by the output means 180 such as a display or a printer. .

  The physical quantity distribution chart creation method and physical quantity distribution chart creation device of the present invention are used to create distribution maps of various physical quantities indoors, such as in houses and schools, as well as outdoors such as farmland, orchards, and forests. Available. Considering that a portion showing a high radiation dose can be extracted with certainty, the present invention is not only industrially usable but also a great social contribution.

DESCRIPTION OF SYMBOLS 100 Physical quantity distribution map creation apparatus 111 Image acquisition means 112 Image extraction means 113 Image selection means 114 Image storage means 121 Measurement means 122 Physical quantity storage means 131 Speed measurement means 132 Movement speed storage means 140 Positioning means 150 Orthogonal image creation means 160 Physical quantity setting means 170 Distribution diagram creating means 180 Output means

Claims (9)

A method of creating a distribution map of different physical quantities for each location within a target range,
While moving the target range, while capturing a plurality of ground images by capturing the ground so that adjacent images overlap, a movement measurement step of measuring a physical quantity,
Based on the physical quantity obtained in the movement measurement step, a physical quantity setting step for giving a representative physical quantity to each of the ground images,
An orthographic image creating step of creating an orthographic image of the target range based on a plurality of the ground images;
A distribution map creating step of creating a physical quantity distribution map by displaying the representative physical quantity on the orthographic image;
A method of creating a physical quantity distribution map, comprising: In the movement measurement step, the radiation dose rate is measured as a physical quantity,
In the physical quantity setting step, a representative radiation dose rate is given to the ground image,
In the distribution map creating step, the representative radiation dose rate is displayed on the orthogonal image.
The method of creating a physical quantity distribution chart according to claim 1. In the movement measurement step, based on the speed of moving the target range, it is determined whether to use the acquired ground image to create the orthographic image,
In the physical quantity setting step, a representative physical quantity is given to the ground image determined to be used for creating the orthographic image in the movement measurement step,
In the orthographic image creation step, the orthographic image of the target range is created based on the ground image determined to be used for creating the orthographic image in the movement measurement step.
The method of creating a physical quantity distribution diagram according to claim 1 or claim 2, wherein In the movement measurement step, the movement distance obtained by moving the target range is acquired, the degree of overlap of adjacent images is obtained based on the movement distance, and the acquired ground image is calculated based on the degree of overlap. Decide whether to use it to create an orthographic image,
In the physical quantity setting step, a representative physical quantity is given to the ground image determined to be used for creating the orthographic image in the movement measurement step,
In the orthographic image creation step, the orthographic image of the target range is created based on the ground image determined to be used for creating the orthographic image in the movement measurement step.
The method for creating a physical quantity distribution map according to any one of claims 1 to 3, wherein In the movement measurement step, the ground is photographed by an image acquisition means fixed at a substantially constant height from the ground,
In the orthographic image creation step, the scale of the ground image is obtained based on the distance between the image acquisition means and the ground, and the orthographic image is created using the orthographic image to which the scale is applied.
The method for creating a physical quantity distribution diagram according to any one of claims 1 to 4, wherein In the movement measurement step, the ground is imaged by the image acquisition means fixed to the support pillar, and the physical quantity is measured by the measurement means fixed to the support pillar.
The method for creating a physical quantity distribution diagram according to any one of claims 1 to 5, wherein: A positioning step of acquiring plane coordinates of two or more points within the target range,
In the orthographic image creation step, based on the plane coordinates acquired in the positioning step, create the orthographic image in which a predetermined coordinate system is set,
The method for creating a physical quantity distribution map according to any one of claims 1 to 6, A physical quantity distribution diagram creation device that creates a distribution map of physical quantities that differ from place to place within a target range,
Image acquisition means fixed at a substantially constant height from the ground, and capable of acquiring a ground image obtained by photographing the ground while moving the target range;
Measuring means for measuring a physical quantity within the target range;
A physical quantity setting means for giving a representative physical quantity to the ground image acquired by the image acquisition means based on the physical quantity measured by the measurement means;
Orthogonal image creation means for creating an orthographic image of the target range based on a plurality of the ground images that overlap adjacent images;
A distribution map creating means for creating a physical quantity distribution map by displaying the representative physical quantity on the orthographic image;
An apparatus for creating a physical quantity distribution diagram, comprising: Speed measuring means for acquiring a moving speed when moving the target range;
Based on the moving speed acquired by the speed measuring means, the image selecting means for selecting the ground image acquired by the image acquiring means as either a used ground image or an unused ground image;
Image storage means for storing the use ground image selected by the image selection means, and
The orthographic image creating means creates the orthographic image of the target range based on the use ground image selected by the image selecting means;
The physical quantity distribution diagram creating apparatus according to claim 8.

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