JP2006011832A - Analytic operation supporting device for aerial photographing image and method for same, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technology to more accurately specify different spots in an aerial photographic image group obtained by photographing the same region at different points of time, and to support an operation to grasp the transition of a photographic region by comparing and observing the aerial photographic image group. <P>SOLUTION: This analysis supporting device for comparing and observing an aerial photographic group obtained by photographing the same region at different points of time, and for supporting an operation to analyze the transition of a photographic region is provided with: a first storage means for storing a first aerial photographic image; a second storage means for storing a second aerial photographic image obtained by photographing the same region as the first aerial photographic image at different point of time; a first specifying means for specifying the shade range of the first aerial photographic image stored in the first storage means; a second specifying means for specifying the shade range of the second aerial photographic image stored in the second storage means; a third specifying means for specifying the range included in only one of the shade range specified by the first specifying means and the shade range specified by the second specifying means; and a display means for displaying the range specified by the third specifying means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for supporting a process of analyzing a transition of a shooting region by comparing and observing a pair of aerial images taken at different points in time in the same region, and in particular, extracting differences between the pair of aerial images. It is related with the technology which supports the work analyzed by.

For example, in order to analyze land use changes in urbanized areas and topographic changes in areas where natural disasters occurred, a pair of aerial images (for example, aerial photographs and satellite images) taken at different times are compared and observed. There is known a technique for extracting the different points and analyzing the transition of the shooting area.
The task of comparatively observing aerial images and extracting differences depends on manual work by the operator, for example, acquired special skills to observe a pair of aerial images independently with the left and right eyes. Professionals are active. In other words, the work of extracting fine differences from a pair of aerial images is extremely difficult and requires a great deal of labor and time.
In view of this, techniques for extracting different points in the aerial image group using image processing techniques have been developed. For example, Patent Document 1 specifies a range in which a building is photographed from a pair of aerial images obtained by photographing the same area at different times, and extracts a change in the range in which the building is photographed. A technique for identifying a point where a building has been changed, such as a new construction, disappearance, or deformation, is described. In this technique, conditions of color and brightness corresponding to a building are set, and it is determined that the building is photographed in a range that satisfies the condition.
JP 2000-222565 A

In the aerial image, buildings of various colors and shapes are photographed. Furthermore, the same building may be photographed in different colors depending on the weather conditions and the like. Therefore, in the method of specifying buildings by color or lightness, it is not possible to set conditions that can specify all buildings, but loose conditions are set to specify more buildings. And many noises other than buildings will be included. The building on the aerial image cannot be accurately specified, and the point where the building has changed cannot be accurately specified.
For example, in natural terrain such as a mountainous area, the colors of trees, soils, and the like vary greatly depending on the season and the climate, so that changes in color and brightness cannot be associated with changes in terrain.
The present invention solves the above problems. The present invention provides a technique for more accurately identifying different points in a pair of aerial images taken at different points in time in the same region, and comparatively observes a pair of aerial images to change the shooting region. Support the analysis work.

The present invention provides an apparatus that supports a work of comparing and observing a pair of aerial images taken at different points in time in the same area and analyzing changes in the shooting area. The analysis support apparatus provided by the present invention includes a first storage unit that stores a first aerial image, and a second aerial image obtained by shooting the same area as the first aerial image at different times. Second storage means stored, first specifying means for specifying a shadow range of the first aerial image stored in the first storage means, and second aerial photography stored in the second storage means Second specifying means for specifying a shadow range of the image, third specifying means for specifying a range included in only one of the shadow range specified by the first specifying means and the shadow range specified by the second specifying means Display means for displaying the range specified by the third specifying means.
The aerial image means an image taken from a high place such as an aerial photograph, a satellite image, or an image obtained by photographing the ground surface from a camera provided on a steel tower.

In the aerial image, the shadows formed by them are photographed together with the buildings etc. For example, when a building etc. is newly established, the shadow is also newly formed, and if the building etc. disappears, the shadow will also disappear . Further, if the building or the like is deformed, the shadow is also deformed, and even if the terrain on which the shadow is projected is deformed, the shadow is deformed. Therefore, by identifying the range where the shadows are captured from aerial images taken at different times in the same area, and extracting changes in the range where the shadows are captured, for example, buildings and topography It is possible to identify the point where the change occurred.
In this apparatus, instead of specifying a range where a building or the like is photographed, a range where a shadow formed by the building or the like is photographed is specified. In the aerial image, there is a sufficient brightness difference between the shadow range and the other range (sunlight range), and the shadow range can be identified accurately from the other ranges. Further, when the building is deformed in the height direction, the range in which the building is photographed is not changed, but the range in which the shadow is photographed is changed. Although the change cannot be extracted by the method of specifying the range where the building or the like is photographed, the change can be extracted by this apparatus. In addition, the shade range can be specified even in natural terrain such as a mountainous area.
According to this apparatus, it is possible to more accurately identify and display different points in a pair of aerial images taken at different points in time in the same region. Can support the work of analyzing the transition of

The third specifying means distinguishes and specifies a range included only in the shadow range specified by the first specifying means and a range included only in the shadow range specified by the second specifying means. Preferably, the display means distinguishes and displays the range identified by the third identifying means.
For example, if the second aerial image is captured later than the first aerial image, and the shadow captured in the first aerial image is not captured in the second aerial image, the first aerial image is captured. It can be inferred that the building, the terrain, etc. that formed the shadow disappeared between the time when the captured image was captured and the time when the second aerial image was captured. In addition, if a shadow that has not been captured in the first aerial image is captured in the first aerial image, the shadow is captured between when the first aerial image is captured and when the second aerial image is captured. It can be inferred that the buildings and topography that formed the Alternatively, if the second aerial image is captured earlier than the first aerial image, the reverse can be estimated.
By distinguishing between the range included only in the shadow range of the first aerial image and the range included only in the shadow range of the first aerial image, from the time of shooting the first aerial image It is possible to grasp the transition of buildings, topography and the like up to the first aerial image.

The shadow range specified by the first specifying means and / or the second specifying means is corrected based on the solar altitude at the time of shooting the first aerial image and the sun altitude at the time of shooting the second aerial image. Preferably it is.
The shade formed by buildings and the like changes depending on the direction of the sun and the altitude (the elevation angle from the horizontal plane). The direction in which buildings and the like are illuminated changes depending on the time of shooting, and the altitude at which the buildings etc. are illuminated changes depending on the calendar at the time of shooting. Strictly speaking, for example, even the same building is the same It is only once a year that the sun is formed.
The inventor of the present invention pays attention to the fact that the solar altitude change width is small compared to the solar direction change width, and the shadow is complicatedly deformed depending on the sun direction, but the shadow deformation due to the solar altitude change is simple. And found that it can be corrected.
If the identified shadow range is corrected based on the solar altitude at the time of shooting of the first aerial image and the second aerial image, it is permitted that the calendars at the time of shooting of the aerial image group are different. The conditions for the shooting time of the aerial image are greatly relaxed, and more aerial images can be used.

The present invention also provides a new and useful method for supporting the work of comparatively observing a pair of aerial images taken at different points in time in the same area and analyzing changes in the shooting area. In this method, a first storage step for storing the first aerial image and a second aerial image obtained by capturing the same area as the first aerial image at different times are stored. A specifying step for specifying a range included only in one of the storage step, the shadow range of the first aerial image stored in the first storage step, and the shadow range of the second aerial image stored in the second storage step And a display step for displaying the range specified in the specific step.
According to this method, it is possible to more accurately identify and display different points in a pair of aerial images taken at different points in time in the same region, and compare and observe a pair of aerial images. Work to analyze the transition of the is supported.

The technology created by the present invention is also embodied in a program that supports a work of comparing and observing a pair of aerial images taken at different points in time in the same region and analyzing changes in the shooting region. The support program stores, in the electronic computer, a first storage unit that stores the first aerial image and a second aerial image obtained by photographing the same area as the first aerial image at different times. A first specifying process for accessing the second storage means, specifying the shadow range of the first aerial image, a second specifying process for specifying the shadow range of the second aerial image, and the first specifying A third specifying process for specifying a range included in only one of the shadow range specified in the process and the shadow range specified in the second specifying process, and a display process for displaying the range specified in the third specifying process are executed. It is a program to let you.
By running this program on a computer, it is possible to more accurately identify and display different points in a pair of aerial images taken at different times in the same region, and compare aerial image groups. The work of observing and analyzing changes in the shooting area is supported.

The technology according to the present invention provides an image that supports a work of comparing and observing a pair of aerial images taken at different points in time in the same region and analyzing changes in the shooting region. The image includes a range included only in one of the shadow range of the first aerial image and the shadow range of another aerial image captured at the same time in the same region as the second aerial image. Is extracted and displayed.
When performing a comparative observation of a pair of aerial images and analyzing the transition of the shooting region, the comparative analysis of the image is supported together with the image to support the operation of analyzing the transition of the shooting region.

  According to the present invention, there is provided a technique for more accurately identifying a point that is different in a pair of aerial images obtained by photographing the same region at different points in time. Analysis work is supported.

First, the main features of the embodiments described below are listed.
(Embodiment 1) The support device includes an image scanner that reads an image or the like printed on a printing medium on a printing medium or the like as electronic information.
(Mode 2) The support apparatus includes an image processing unit that binarizes an image based on pixel brightness.
(Mode 3) The support device includes a storage unit that stores the relationship between the date and time and the sun position (direction and altitude).
(Mode 4) The support apparatus includes a printer that prints an image or the like on a print medium on photographic paper or the like.

Embodiment 1 Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings.
This embodiment uses a technique of the present invention to provide a device that supports the work of analyzing changes in buildings, topography, etc. by comparing and observing a pair of aerial images taken at the same position at different times. This is an example. The aerial image referred to here means an image obtained by photographing an aerial photograph, a satellite image, or a ground surface photographed by a camera installed at a high place such as a steel tower from a high place.
Further, the image includes an image displayed on a display or the like, a printed matter or a photograph printed on a print medium.
FIG. 1 shows the configuration of the support device 10 of the present embodiment. The support device 10 includes a storage unit 20, a processing unit 30, an image scanner 12 that converts an image printed on a print medium such as photographic paper into electronic information, and a display that displays various types of information to the user of the support device 10. The apparatus 14 includes a printer 16 that prints an image or the like on a printing medium such as photographic paper. The support device 10 can be configured using, for example, a general-purpose personal computer, a general-purpose image image scanner, a general-purpose printer, or the like. In this embodiment, a general-purpose personal computer is used and is not shown, but includes an input interface such as a keyboard and a mouse, and an apparatus for inputting and outputting electronic information such as an optical disk drive.

  The storage unit 20 includes a first image information storage unit 21 and a second image information storage unit 22. The first and second image information storage units 21 and 22 can store, for example, aerial images converted into electronic information. The first and second image information storage units 21 and 22 can store color image information describing color information for each pixel. The first and second image information storage units 21 and 22 of the support apparatus 10 may store monochrome image information that describes only brightness information for each pixel. The 1st, 2nd image information storage parts 21 and 22 can memorize | store together the imaging | photography date of the stored aerial image. In addition, the storage unit 20 can store image information and the like generated by the processing unit 20 in processing to be described later.

The processing unit 30 includes an input processing unit 32, a binarization processing unit 34, a shadow correction processing unit 36, a comparison processing unit 38, an output processing unit 40, and the like.
The input processing unit 32 performs processing for inputting an aerial image prepared by the user and the shooting date and time of the aerial image to the support apparatus 10. The binarization processing unit 34 performs a process of specifying a shadow range captured in the aerial image from the aerial image information stored in the storage unit 20. The shadow correction processing unit 36 performs processing for correcting the shadow range specified by the binarization processing unit 34 based on the solar altitude of the shooting date and time. The comparison processing unit 38 compares the shadow ranges specified from the two aerial images and modified as necessary, and performs a process of extracting a range included only in one of the shadow ranges. The output processing unit 40 displays the range or the like extracted by the comparison processing unit 38 on the display device 14 or instructs the printer 16 to print and display it on a print medium.

  Next, the operation of the support apparatus 10 will be described in detail. In the following, description will be given by taking as an example an operation of using the support device 10 to compare and observe two aerial images taken at different times at the same position and identify changes in buildings, topography, and the like. . FIG. 2 is a flowchart showing the operation flow of the support apparatus 10. In the following description, for two aerial images prepared by the user, the aerial image captured first is referred to as a first aerial image, and the aerial image captured later is referred to as a second aerial image.

In step S <b> 2 of FIG. 2, the user teaches the support device 10 with the first aerial image. The input processing unit of the support apparatus 10 includes 32, for example, a driver for operating the image scanner 12, and the image scanner 12 converts the first aerial image into electronic information and reads the image information of the first aerial image. Are stored in the first image information storage unit 21. At this time, the first aerial image may be stored as a color image or may be stored as a monochrome image. It is only necessary that the brightness is described for each pixel. The input processing unit 32 also includes a driver for operating an optical disk drive, for example, and can read image information described in a recording medium such as an optical disk and store it in the storage unit 20. Therefore, the aerial image prepared by the user may be an aerial image printed on photographic paper or the like, or may be an aerial image already converted to electronic information.
FIG. 3 illustrates the first aerial image 50 stored in the first image information storage unit 21. As shown in FIG. 3, for example, a T-junction 52 is captured in the first aerial image 50. In addition, the waste disposal factory 54 and its shadow 54a are photographed. A chimney 56 and a shadow 56a of the waste treatment factory 54 are photographed. Also, a one-storied house 62 and its shadow 62a are photographed. In addition, the building 60 under construction and its shadow 60a are photographed. Note that the first aerial image 50 is taken, for example, at “1:30 pm on April 1, 1999”.
In step S4, the user inputs the shooting date and time of the first aerial image 50. The shooting date and time can be input using an input interface such as a keyboard. At this time, the user inputs, for example, “April 1, 1999 1:30 pm” or the like. The input processing unit 32 stores the input shooting date / time in the first image information storage unit 21.

In step S6, the second aerial image is taught to the support apparatus 10 in the same manner as in step S2.
FIG. 4 illustrates a second aerial image 70 stored in the second image information storage unit 21. As shown in FIG. 4, the second aerial image 70 is an image of the same area as the first aerial image 50. For example, a T-junction 52 is captured. In addition, the waste disposal factory 54 and its shadow 54a are photographed. A chimney 56 and a shadow 56a of the waste treatment factory 54 are photographed. In addition, a piled waste group 58 is photographed below the waste factory 54, and a shadow 56 a of the chimney 56 extends to the waste group 58. The building 61 and its shadow 61a are photographed. Also, a two-story house 63 and its shadow 63a are photographed. In addition, the houses for sale 72, 74, 76 and their shadows 72a, 74a, 76a are photographed. It is assumed that the second aerial image 70 was taken at, for example, “1:30 pm on June 1, 2004”.
In step S8, the user inputs the shooting date and time of the second aerial image 70 in the same manner as in step S4. At this time, the user inputs, for example, “1:30 pm on June 1, 2004”.

In step S <b> 10, a process of specifying the shadow range captured in the first aerial image 50 is performed by the process of the binarization processing unit 34. The process of step S10 will be described.
The binarization processing unit 34 calculates the brightness for each pixel of the first aerial image 50 stored in the first image information storage unit 21. Next, the calculated brightness of the pixel is compared with a threshold corresponding to the brightness of the shadow range. That is, threshold processing is performed. As the threshold used at this time, a value stored in advance by the binarization processing unit 34 can be used, or for example, a user of the support apparatus 10 can set the threshold. When the user sets a threshold value corresponding to the brightness of the shadow range, for example, the support device 10 displays the first aerial image 50 on the display device 14, and the user determines the shadow range on the displayed image. When instructed with a mouse or the like, the brightness of the position may be set as a threshold value. The binarization processing unit 34 assigns a value of “0 (zero)” or “1” for each pixel based on the comparison result. For example, “0” is assigned if the brightness of the pixel is greater than the threshold, and “1” is assigned if the brightness of the pixel is less than the predetermined threshold. As a result, “0” is assigned to the pixels located in the sunny range, and “1” is assigned to the pixels located in the shaded range. In the first aerial image 50 shown in FIG. 3, the shadow 54a of the waste processing factory 54, the shadow 56a of the chimney 56 of the waste processing factory 54, the shadow 60a of the building 60 under construction, the shadow 62a of the house 62, etc. “1” is assigned to pixels located in the range where the image is captured, and “0” is assigned to pixels located in other ranges. By the processing in step S10, a binarized image 81 shown in FIG. 5 is generated. In FIG. 5, the range of pixels to which “1” is assigned is indicated by hatching, and corresponds to the shadow range of the first aerial image 50 shown in FIG. The binarized image 81 is an image that describes only the shadow range from the first aerial image 50. In FIG. 5, buildings and the like are indicated by broken lines, but this is for the purpose of clarifying the illustration and is not described in the binarized image 81. Hereinafter, the binarized image 81 is referred to as a first shadow image 81. In an aerial image, there is a large difference between the brightness of the sunny range and the brightness of the shade range. Therefore, by performing threshold processing on the brightness, the sunny range and the shade range can be correctly distinguished.
Hereinafter, the value of the pixel located at (i row, j column) in the first shadow image 81 may be described as A (i, j). As is clear from the above, A (i, j) has a value of “0” or “1”. If A (i, j) = 1, it means that the pixel located in (i row, j column) of the first aerial image 50 is located in the shadow range.

In step S12, the shadow range captured in the second aerial image is specified. In step S12, substantially the same processing as in step S10 is performed, and a second binarized image 82 shown in FIG. 6 is generated. As shown in FIG. 6, the range of pixels to which “1” is assigned in the second binarized image 82 (hatched portion in FIG. 6) is the shadow range of the second aerial image 70 shown in FIG. Correspond. A binarized image 82 shown in FIG. 6 is an image that describes only the shadow range of the second aerial image 70. Hereinafter, this binarized image 82 is referred to as a second shadow image 82.
Hereinafter, the value of the pixel located at (i row, j column) in the second shadow image 82 may be described as B (i, j). As is clear from the above, B (i, j) has a value of “0” or “1”. If B (i, j) = 1, it means that the pixel located in (i row, j column) of the second aerial image 70 is located in the shadow area.

In step S14, the shadow correction processing unit 36 processes the shadow range of the first aerial image 50 specified in step S10 and the shadow range of the second aerial image specified in step S12. A process for correcting an error based on the difference in solar altitude is performed. For example, since the first aerial image 50 was taken in April and the second aerial image 70 was taken in June, the first aerial image 50 is taken even at the same time. The altitude of the sun is higher when shooting the second aerial image 70 (here, the northern hemisphere is used as a reference). Therefore, the shadow of the second aerial image 70 is shorter than the first aerial image 50 with respect to the building having the same height. In step S14, the error due to the difference in solar altitude is eliminated.
The process of step S14 will be described with reference to FIG. 7 is an arrow view of the waste treatment factory 54 and its chimney 56 as viewed from the direction of the arrow X shown in FIG. The arrow X direction is a horizontal direction and a direction perpendicular to the direction of the sun. The right side of the drawing in FIG. 7 is the direction of the sun, and a shadow 56 a of the chimney 56 is projected on the ground surface 4. In FIG. 7, an arrow 1 indicates the incident direction of sunlight when the first aerial image 50 is captured. An angle θ <b> 1 formed by the arrow 1 and the horizontal plane 3 indicates the solar altitude at the time of shooting the first aerial image 50. An arrow 2 indicates the incident direction of sunlight when the second aerial image 70 is captured. An angle θ2 formed by the arrow 2 and the horizontal plane 3 indicates the solar altitude when the second aerial image 70 is captured.

As shown in FIG. 7, when the solar altitude is the angle θ1 and the length of the shadow 56a of the chimney 56 is L1, if the height of the chimney 56 is H,
H = L1 · tan θ1 (1);
It is expressed. The length of the shadow here means the length that the shadow extends in the direction opposite to the direction of the sun as generally understood.
On the other hand, when the height of the chimney 56 is H and the solar altitude is the angle θ2, if the length of the shadow 56a formed at that time is L2,
L2 = H / tan θ2 (2);
It is expressed. From the above equations (1) and (2),
L2 = L1 · (tan θ1 / tan θ2) (3);
It is expressed. From the above equation (3), the length L1 of the shadow 56a of the chimney 56 captured in the first aerial image 50, the solar altitude θ1 at the time of capturing the first aerial image 50, and the second aerial image The length L2 of the shadow 56a formed when the chimney 56 at the time of photographing the first aerial image 50 is illuminated by the sun at the time of photographing the second aerial image 70 is calculated from the solar altitude θ2 at the time of photographing 70. can do. The shadow correction processing unit 36 uses this algorithm.

The shadow correction processing unit 36 reads the shooting date and time of the first and second aerial images 50 and 70 from the first and second image information storage units 21 and 22, and stores the date and sun position (direction and sun position) stored in advance. The sun position (direction 3 and solar altitudes θ1 and θ2) at the time of shooting the first and second aerial images 50 and 70 is specified by referring to the relationship of altitude. Next, for example, the shadow correction processing unit 36 sets a shadow range (range of A (i, j) = 1) described in the first shadow image 81 in a direction opposite to the identified sun direction (tan θ1 / tan θ2) is expanded and contracted to generate a third binarized image. Hereinafter, this third binarized image is referred to as a first modified shadow image.
FIG. 8 illustrates the first modified shadow image 86. The length L1 of the shadow range of the first shadow image 81 shown in FIG. 5 and the length L2 of the shadow range of the first corrected shadow image 86 shown in FIG. 8 are L2 / L1 = (tan θ1 / tan θ2). It becomes the relationship. The first modified shadow image 86 describes a shadow formed when the sun at the time of photographing the second aerial image 70 illuminates the building or the terrain in the state at the time of photographing the first aerial image 50. ing. By the processing in step S14, it is allowed that the solar altitude is different between the first aerial image 50 and the second aerial image 70 (that is, the calendar at the time of shooting is different).
The above processing may be performed on, for example, the second shadow image 82, or, for example, a reference value for the solar altitude is determined, and the first and second shadow images 81, 82 are determined based on the reference altitude. It may be performed for both.
Hereinafter, the value of the pixel located at (i row, j column) in the first modified shadow image 86 may be described as C (i, j). As is apparent from the above, C (i, j) has a value of “0” or “1”. If C (i, j) = 1, the pixel located in (i row, j column) of the first aerial image 50 indicates the building, topography, etc. in the state at the time of shooting the first aerial image 50. This means that the second aerial image 70 is located in the shaded range formed when the sun is illuminated.

In subsequent steps S16, S18, S20, S22, S24, S26, and S28, the comparison processing unit 36 describes the shadow range described by the first corrected shadow image 86 and the shadow range described by the second shadow image 82. Are compared, and a range included in only one of these ranges is extracted. The process of these step S16-step S28 is demonstrated.
In step S16, the pixel position (i row, j column) is determined, and the value C (i, j) of the first modified shadow image 86 is compared with the value B (i, j) of the second shadow image 82. If they are equal, the process proceeds to step S18, and if they are different, the process proceeds to step S20.
In step S18, it is determined whether or not the value C (i, j) of the first corrected shadow image 86 is “0”. If the value C (i, j) of the first modified shadow image 86 is “0”, the process proceeds to step S22, and if not, the process proceeds to step S24.
In step S <b> 22, a value “0” is assigned to the pixel position (i row, j column) and stored in the storage unit 20. In step S <b> 24, a value “1” is assigned to the pixel position (i row, j column) and stored in the storage unit 20.

On the other hand, when proceeding from step S16 to step S20, it is determined whether or not the value C (i, j) of the first corrected shadow image 86 is “1”. If the value C (i, j) of the first modified shadow image 86 is “1”, the process proceeds to step S26, and if not, the process proceeds to step S28.
In step S <b> 26, a value “2” is assigned to the pixel position (i row, j column) and stored in the storage unit 20. In step S <b> 28, a value “3” is assigned to the pixel position (i row, j column) and stored in the storage unit 20.
The processes in steps S16 to S28 are performed for all pixel positions. Thereby, the storage unit 20 is a four-value in which any one of the values “0”, “1”, “2”, and “3” is described for the pixel position (i row, j column). Image information is generated. FIG. 9 shows a quaternized image 88 generated by the processes in steps S16 to S28. In FIG. 9, a range P in which a point sequence pattern is written indicates a range to which the value “1” is assigned. A range Q in which horizontal stripes are marked in FIG. 9 indicates a range to which the value “2” is assigned. A range R (R1 to R5) in which vertical stripes are marked in FIG. 9 indicates a range to which the value “3” is assigned. The white blank range in FIG. 9 indicates a range to which the value “0” is assigned. This quaternized image 88 is referred to as a “shadow change image 88”.
Hereinafter, the value of the pixel located at (i row, j column) in the shadow transition image 88 may be described as D (i, j). As is clear from the above, D (i, j) takes one of the values “0”, “1”, “2”, and “3”.

If D (i, j) = 0 in the shadow transition image 88, C (i, j) = 0 in the first modified shadow image 86 and B (i, j) in the second shadow image 82. = 0. This is because the range indicated by white in FIG. 9 is not included in the shadow range described by the first modified shadow image 86 but is included in the shadow range described by the second shadow image 82. Means not. That is, the range indicated by white spots in FIG. 9 is not included in the corrected shadow range of the first aerial image 50 and is not included in the shadow range of the second aerial image 70. Means that.
If D (i, j) = 1 in the shadow transition image 88, C (i, j) = 1 in the first modified shadow image 86 and B (i in the second shadow image 82. , J) = 1. That is, the range P shown in FIG. 9 is included in the corrected shadow range of the first aerial image 50 and is also included in the shadow range of the second aerial image 70. .
On the other hand, when D (i, j) = 2 in the shadow transition image 88, C (i, j) = 1 in the first modified shadow image 86 and B (i, j) in the second shadow image 82. j) means 0. That is, the range Q shown in FIG. 9 indicates a range that is included in the corrected shadow range of the first aerial image 50 but is not included in the shadow range of the second aerial image 70. Yes. This is because, in the vicinity of the position indicated by the range Q of the shadow transition image 88, the building or the like that existed when the first aerial image 50 was captured does not exist when the second aerial image 70 was captured. It is shown that. Alternatively, at the position indicated by the range Q of the shadow transition image 88, the ground surface or the like has been deformed between the time when the first aerial image 50 is captured and the time when the second aerial image 70 is captured (the construction has been newly established). Also included).
Further, when D (i, j) = 3 in the shadow transition image 88, C (i, j) = 0 in the first modified shadow image 86 and B (i, j) in the second shadow image 82. j) = 1. That is, the range R shown in FIG. 9 is not included in the corrected shadow range of the first aerial image 50, but is included in the shadow range of the second aerial image 70. Yes. This is because, in the vicinity of the position indicated by the range R of the shadow transition image 88, a building or the like that does not exist when the first aerial image 50 is captured exists when the second aerial image 70 is captured. It shows that. Or, the position indicated by the range Q of the shadow transition image 88 indicates that the ground surface or the like has been deformed between the time when the first aerial image 50 is captured and the time when the second aerial image 70 is captured.

In subsequent steps S30 and S32, the processing result of the above steps is displayed to be observable to the user or the like by the processing of the output processing unit 40.
In step S <b> 30, the user instructs a range to be displayed on the support device 10. For example, in the first aerial image 50 and the second aerial image 70, the user changes the range from the shaded range to the sunny range (range Q in FIG. 9) or changes from the sunny range to the shaded range. Range (range R in FIG. 9), a range in which both are shaded ranges (range P in FIG. 9), a range in which both are in the sunny range (range of white spots in FIG. 9), etc. It is possible to instruct to display one or more of the ranges at the same time. When a plurality of ranges are displayed at the same time, it can be instructed whether to display all the ranges separately or whether to display the plurality of ranges without distinction. Here, for example, in the first aerial image 50 and the second aerial image 70, for example, the range in which the shadow range changes from the shade range to the sunny range, and the range in which the range changes from the sunny range to the shade range. Suppose that a range that is a range is specified to be displayed separately.
In step S <b> 32, based on the operator's instruction in step S <b> 30, the output processing unit 40 displays the shadow transition image 88 stored in the storage unit 20 on the display 14. Alternatively, it is printed on a print medium by the printer 16 and displayed. When displaying the shadow transition image 88, the output processing unit 40 sets a display color for each pixel value (here, “0” to “3”), and can display, for example, a four-color image. it can. Further, for example, the same color can be set for different pixel values, and the shadow transition image 88 can be displayed as, for example, a single-color image or a two-color image. Here, based on the instruction in the previous step S30, if D (i, j) = 0 for the pixel located at (i row, j column), the first color is set, and D (i, j ) = 1 to set the second color, D (i, j) = 2 to set the third color, and D (i, j) = 3 to set the fourth color. To do. At this time, when colors having different color tones (for example, opposite colors) are employed as the first to fourth colors, the operator can easily observe the displayed image. The displayed image is, for example, an image in which the shadow transition image 88 shown in FIG. 9 is expressed in four colors. At this time, for example, the shadow transition image 88 may be superimposed and displayed on the second aerial image 70. When displayed in this way, the range in which the shadow range has changed is displayed on the second aerial image 70 in a color-coded manner, which is easy for the operator to observe.

When the shadow transition image 88 shown in FIG. 9 is displayed, the operator can easily specify the position where the shadow range is changing in the first aerial image 50 and the second aerial image 70. . If the position where the shadow range is changing can be identified, it can be known that there has been some change in the building, topography, etc. in the vicinity. For example, paying attention to the fact that the ranges R1, R2, and R3 are displayed in the shadow transition image 88 shown in FIG. 9, comparing the first aerial image 50 and the second aerial image 70, the condominium 72, It can be easily found that 74 and 76 are newly provided. Further, when the first and second aerial images 50 and 70 are compared and observed focusing on the range R4 displayed in the shade transition image 88, the one-storied house 62 is changed to a two-story house 63. Can easily find out. It can be inferred that the second-floor part was added to the one-storied house 62. In addition, when the first and second aerial images 50 and 70 are compared and observed by paying attention to the range R5 displayed in the shade transition image 88, the building 60 under construction changes to a completed building 61. Can be easily found. Thus, it can be easily found that the height direction of a building or the like is changed.
On the other hand, when the first and second aerial images 50 and 70 are compared and observed focusing on the display of the range Q in the shadow transition image 88, the waste group 58 is piled up in the vicinity of the waste treatment factory 54. Can be easily found. Thus, even if there is no change in the chimney 56 that forms the shadow, it is possible to find a change in the topography and the like on which the shadow 56a is projected from the change in the shadow 56a of the chimney 56.
As described above, the support device 10 of the present embodiment is used in the work of comparing and observing a pair of aerial images taken at different times at the same position and grasping the transition of buildings, topography, and the like. Then, it is possible to easily find a building, a terrain, or the like that changes between the two aerial images.

As mentioned above, although embodiment of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
In the above-described embodiment, the case where a change in a building in an urban area is specified has been described as an example. However, the support device 10 of the present embodiment is also effective in specifying a landslide in a mountainous area, for example. is there.
In addition, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technology illustrated in this specification or the drawings achieves a plurality of objects at the same time, and achieving one of the objects itself has technical utility.

The figure which shows the structure of a assistance apparatus. The flowchart which shows the flow of operation | movement of a assistance apparatus. The figure which shows a 1st aerial image. The figure which shows a 2nd aerial image. The figure which shows a 1st shadow extraction image. The figure which shows a 2nd shadow extraction image. The figure which shows a 1st correction shadow image. The figure which shows the relationship between the solar height and the length of the shadow formed. The figure which shows a shadow change image.

Explanation of symbols

10. Support device 12 Image scanner 14 Display device 16 Printer 20 Storage unit 21 First image information storage unit 22 Second image information storage unit 30 Processing unit 50 First aerial image 70 .. Second aerial image 81.. First shadow image 82. Second shadow image 86. First modified shadow image 88.

Claims (6)

It is a device that supports the work of comparatively observing a pair of aerial images taken at different times in the same area and analyzing the transition of the shooting area,
First storage means for storing a first aerial image;
Second storage means for storing a second aerial image obtained by photographing the same area as the first aerial image at a different time point;
First specifying means for specifying a shadow range of the first aerial image stored in the first storage means;
Second specifying means for specifying the shadow range of the second aerial image stored in the second storage means;
A third specifying means for specifying a range included only in one of the shadow range specified by the first specifying means and the shadow range specified by the second specifying means;
Display means for displaying the range specified by the third specifying means;
A support apparatus comprising: The third specifying means distinguishes between a range included only in the shadow range specified by the first specifying means and a range included only in the shadow range specified by the second specifying means. And
The support device according to claim 1, wherein the display unit distinguishes and displays the range identified by the third identification unit.   The shadow range specified by the first specifying means and / or the second specifying means is corrected based on the solar altitude at the time of shooting the first aerial image and the sun altitude at the time of shooting the second aerial image. The support device according to claim 1, wherein the support device is a device. It is a method that supports the work of comparing and observing a pair of aerial images taken at different times in the same area and analyzing changes in the shooting area.
A first storage step for storing a first aerial image;
A second storage step of storing a second aerial image obtained by photographing the same area as the first aerial image at a different time point;
A specifying step for specifying a range included in only one of the shadow range of the first aerial image stored in the first storage step and the shadow range of the second aerial image stored in the second storage step;
A display process for displaying the range specified in the specific process;
A support method comprising: A program that supports the work of comparatively observing a pair of aerial images taken at different times in the same area and analyzing the changes in the shooting area.
Access to the first storage means storing the first aerial image and the second storage means storing the second aerial image of the same area as the first aerial image taken at different times. And
A first specifying process for specifying a shadow range of the first aerial image;
A second specifying process for specifying the shadow range of the second aerial image;
A third specifying process for specifying a range included only in one of the shadow range specified in the first specifying process and the shadow range specified in the second specifying process;
A display process for displaying the range identified in the third identification process;
Support program that runs It is an image that supports the work of comparatively observing the first aerial image and the second aerial image taken at different times in the same region and analyzing the transition of the imaged region,
An image in which a range included in only one of the shadow range of the first aerial image and the shadow range of the second aerial image is extracted and displayed.

Images