JP5572053B2 - Orientation estimation apparatus and program - Google Patents

Description

  The present invention relates to a technique for estimating an azimuth using sunlight.

  An apparatus that estimates a direction using a geomagnetic sensor or GPS (Global Positioning System) is known. However, when a geomagnetic sensor is used, the apparatus cannot accurately measure the direction because the geomagnetism is disturbed when there is a magnetic substance nearby, in a building street, near a railroad crossing, on a railway bridge, on a subway, or indoors. Further, when estimating the azimuth using GPS, the azimuth is estimated from the moving direction. Therefore, such an apparatus needs to be moved, and the azimuth cannot be measured in a stationary state. Furthermore, since the GPS receives radio waves from satellites and specifies the position, the accuracy of measurement of such a device decreases in a building district or indoors.

  On the other hand, a technique for detecting the direction of the sun based on the polarization characteristics of sunlight has been developed. Patent Document 1 discloses a technique for calculating the solar direction at the initial launch of an artificial satellite. Patent Document 2 discloses a technique for controlling the emission of photographing auxiliary light by acquiring images through two polarizing plates provided at different angles and detecting the position of the sun from the difference value of each image. Has been.

JP 7-248225 A JP 2004-117478 A

  However, the technique disclosed in Patent Document 1 relates to detecting the direction of the sun as viewed from an artificial satellite in outer space, and the technique disclosed in Patent Document 2 is related to the relationship between the camera and the sun, such as backlight. It is only to detect a general directional relationship. Neither document estimates the orientation on the earth's surface.

  An object of the present invention is to estimate the azimuth using sunlight on the ground surface.

  In order to solve the above-described problems, an azimuth estimation apparatus according to the present invention includes astronomical information acquisition means for acquiring celestial information indicating the motion of the sun with respect to the earth, date / time information acquisition means for acquiring date / time information, Each of the light intensity from the position information acquisition means for acquiring the position information indicating the light intensity and the detection means for separating the sunlight irradiated to the device into a plurality of polarization components and detecting the light intensity of each of the separated polarization components. Light intensity information acquisition means for acquiring light intensity information indicating the position, attitude information acquisition means for acquiring attitude information indicating the attitude of the device relative to a certain direction, and the celestial body acquired by the celestial body information acquisition means With reference to the information, on the date and time indicated by the date and time information acquired by the date and time information acquisition means, the direction of the sun in horizon coordinates with the position indicated by the position information acquired by the position information acquisition means as the origin Based on each light intensity indicated by the light intensity information acquired by the first estimation means to be determined, the light intensity information acquisition means, and the attitude information acquired by the attitude information acquisition means, the self apparatus is used as a reference. Second estimation means for estimating the direction of the sun, and orientation estimation for estimating the orientation in the horizontal coordinates with the position of the device as the origin, according to each direction estimated by the first estimation means and the second estimation means Means.

  Further, the azimuth estimation apparatus according to the present invention acquires celestial information acquisition means for acquiring celestial information indicating the movement of the sun with respect to the earth, date / time information acquisition means for acquiring date / time information, and position information indicating the position of the own apparatus. Light intensity information indicating the respective light intensities from the position information acquisition means for detecting and the detecting means for separating the sunlight irradiated to the device into a plurality of polarization components and detecting the light intensity of each of the separated polarization components. With reference to the celestial information acquired by the light intensity information acquisition means to acquire, the attitude information acquisition means for acquiring the attitude information indicating the attitude of the own device with reference to a certain direction, the celestial information acquisition means, First estimating means for estimating the direction of the sun in horizon coordinates with the position indicated by the position information acquired by the position information acquiring means as the origin at the date and time indicated by the date and time information acquired by the date and time information acquiring means; Second estimation means for estimating the direction of the sun with reference to the device according to each light intensity indicated by the light intensity information acquired by the light intensity information acquisition means; the first estimation means; and the second estimation means. Azimuth estimating means for estimating the direction in the horizontal coordinate with the position of the own apparatus as the origin in accordance with each direction estimated by the estimating means and the attitude information acquired by the attitude information acquiring means. And

  Preferably, the second estimating means estimates the sun direction according to the difference in light intensity.

  Preferably, the detection unit includes an imaging unit that performs imaging through a plurality of polarization filters having different polarization directions, and the light intensity information acquisition unit is configured to capture each image captured by the imaging unit through each of the polarization filters. Lightness information indicating the lightness of the image may be acquired as the light intensity information.

  Preferably, the detection unit includes an imaging unit that performs imaging through a filter in which a plurality of polarization filters having different polarization directions are arranged, and the light intensity information acquisition unit is configured to capture the image captured by the imaging unit. Lightness information indicating a lightness arrangement pattern may be acquired as the light intensity information.

  Preferably, the detection unit includes an imaging unit that performs imaging through a polarization filter, and a rotation driving unit that rotates the polarization filter to change a polarization component that is transmitted to the imaging unit.

  Preferably, the detection means includes an image pickup means for picking up an image through a liquid crystal, and a liquid crystal control means for changing a polarization component transmitted by the liquid crystal by changing an applied voltage.

  In addition, the program according to the present invention stores storage means for storing astronomical information indicating the movement of the sun with respect to the earth, a clock for outputting date and time information, and measures the position of the own device and outputs position information indicating the position. Positioning means, detection means for separating sunlight irradiated to the apparatus into a plurality of polarized components, and detecting the light intensity of each separated polarization component, and the attitude of the apparatus with respect to a certain direction A computer comprising posture detecting means for detecting; from the storage means; astronomical information acquisition means for acquiring the celestial information; from the clock; date / time information acquisition means for acquiring the date / time information; from the positioning means; The position information acquisition means for acquiring position information, the light intensity information acquisition means for acquiring light intensity information indicating each light intensity from the detection means, and the attitude detection means indicate the attitude of the device itself. Reference is made to the posture information acquisition means for acquiring the trend information and the celestial information acquired by the celestial information acquisition means, and the position information acquisition means acquires the date and time indicated by the date and time information acquired by the date and time information acquisition means. First estimation means for estimating the direction of the sun in horizon coordinates with the position indicated by the position information as the origin, each light intensity indicated by the light intensity information acquired by the light intensity information acquisition means, and the attitude information acquisition means According to the posture information acquired by the second estimation means for estimating the direction of the sun with reference to the own device, and according to each direction estimated by the first estimation means and the second estimation means, This is a program for functioning as azimuth estimation means for estimating the azimuth in the horizon coordinate with the position of its own device as the origin.

  According to the present invention, it is possible to estimate the azimuth using sunlight on the ground surface.

It is a figure which shows the structure of the azimuth | direction estimation apparatus which concerns on 1st Embodiment. It is a figure which shows the external appearance of an azimuth | direction estimation apparatus. It is a figure which shows the functional structure of an azimuth | direction estimation apparatus. It is the schematic which shows the horizon coordinate system which makes the origin the position of an azimuth | direction estimation apparatus. It is a figure explaining the relative direction of the sun. It is a figure showing the change of the brightness difference with respect to the angle which the imaging direction forms with respect to the sun direction. It is the figure which illustrated two images when the brightness difference increased most. It is a figure which shows the functional structure of the azimuth | direction estimation apparatus which concerns on 2nd Embodiment. It is a figure explaining that a relative direction estimation part estimates the relative direction of the sun. It is a figure showing the apparatus coordinate system with respect to a ground plane. It is a figure explaining the relative direction of the sun estimated by the relative direction estimation part. It is a figure explaining the azimuth | direction angle of the imaging direction calculated by the azimuth | direction estimation apparatus. It is a figure which shows an example of the polarizing filter in a modification. It is a figure which shows another example of the polarizing filter in a modification.

Hereinafter, modes for carrying out the present invention will be described.
1. First embodiment 1-1. Configuration 1-1-1. Configuration of Orientation Estimation Device FIG. 1 is a diagram illustrating a configuration of an orientation estimation device 1 according to the first embodiment of the present invention. The azimuth estimation device 1 can be mounted on various devices such as a digital still camera, a mobile phone, an electronic book display, a game machine, a portable music player, and a portable video player. Here, the azimuth estimation device 1 is a mobile phone.

  The control unit 11 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and the CPU stores a boot loader stored in the ROM and a computer program stored in the storage unit 12. Each part of the azimuth estimation apparatus 1 is controlled by reading (hereinafter simply referred to as a program) and executing the RAM as a work area.

  The storage unit 12 is a large-capacity storage unit such as an EEPROM (Electrically Erasable Programmable Read Only Memory), and stores a program read by the CPU of the control unit 11. In addition, the storage unit 12 stores astronomical information 121 that is information indicating movements such as rotation and revolution of solar system celestial bodies including the earth.

  The operation unit 13 includes an operation element for inputting various instructions. The operation unit 13 receives an operation by a user and supplies a signal corresponding to the operation content to the control unit 11. The display unit 14 displays an image in response to an instruction from the control unit 11. The display unit 14 includes, for example, a display body such as a liquid crystal display.

  The clock unit 15 measures the date and time and outputs date and time information indicating the measured date and time. The clock unit 15 may be a so-called radio clock having a function of receiving a standard radio wave and correcting an error in date and time.

  The communication unit 16 has a wireless communication function, reads the identification information of the wireless base station, identifies the position of the azimuth estimation apparatus 1, and outputs position information indicating this position. This position information is information indicating the communication area of the radio base station identified by the identification information. This position information describes the latitude and longitude assigned to the representative point in this communication area.

The image capturing unit 17 includes two optical members 171a and 171b (hereinafter referred to as “optical elements”) that receive light from a target and an image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor. When there is no need for distinction, these are expressed as an optical member 171). The optical member 171 includes a polarizing filter in addition to a lens, a reflecting mirror, a prism, and the like. In each optical member 171, the polarizing filters are provided so that their polarization directions are different from each other. For example, the angle formed by the polarization directions of the polarization filters of the optical members 171a and 171b is 90 degrees.
And the imaging part 17 outputs the image data which show each image Pa and Pb imaged through the polarizing filter with which these two optical members 171a and 171b were equipped.

  The posture detection unit 18 is a three-axis acceleration sensor, and measures the angle formed by each coordinate axis of the device coordinate system, which is a coordinate system defined along each configuration of the orientation estimation device 1, with respect to the direction of gravity. The orientation of the orientation estimation device 1 is detected, and orientation information indicating this orientation is output.

  Here, the apparatus coordinate system will be described. FIG. 2 is a diagram illustrating an appearance of the azimuth estimation device 1. As shown in FIG. 2A, two optical members 171 a and 171 b of an operation unit 13, a display unit 14, and an imaging unit 17 are arranged on one surface of the azimuth estimation device 1. The display body of the display unit 14 has an outline conforming to a rectangle, and the x axis and the y axis are defined along two sides of the rectangle orthogonal to each other. A z axis is defined in a direction orthogonal to the x axis and the y axis. The orthogonal coordinate system represented by the x-axis, y-axis, and z-axis is the apparatus coordinate system. The origin of the device coordinate system is, for example, the center of gravity of the orientation estimation device 1.

  Hereinafter, in the figure, a symbol in which “•” is written inside “◯” is a symbol indicating a direction from the back to the front of the page. The direction in which the component in the x-axis direction increases is referred to as the x (+) direction, and the direction in which the component in the x-axis direction decreases is defined as the x (−) direction (the same applies to the y-axis and z-axis). That is, the orthogonal coordinate system represented by x, y, z in the figure is a right-handed system.

  Each optical member 171 is oriented in a direction perpendicular to the display surface on which the display body of the display unit 14 displays an image. Therefore, the imaging direction of the imaging unit 17 is the z (+) direction. The directional component Da shown in FIG. 2A is a directional component along the y-axis direction, and the polarizing filter included in the optical member 171a has a polarization characteristic that allows linearly polarized light having the directional component Da to pass therethrough. Similarly, the direction component Db is a direction component along the x-axis direction, and the polarization filter included in the optical member 171b has a polarization characteristic that allows linearly polarized light having the direction component Db to pass therethrough. Therefore, the direction component Da and the direction component Db are orthogonal to each other.

  When the azimuth estimation device 1 estimates the azimuth, a compass diagram representing the estimated azimuth is displayed on the display unit 14 as shown in FIG. In this compass diagram, for example, a compass diagram drawn on the ground plane is orthogonally projected onto the display surface of the display unit 14 by parallel rays perpendicular to the ground plane. For example, it is assumed that a line is drawn from the center point of the compass diagram toward the point displayed as “north”. When this line is orthogonally decomposed into a first component parallel to the ground plane and a second component parallel to the direction of the zenith as viewed from the origin O, the decomposed first component points to “north”.

  In addition, the azimuth estimation device 1 that is a mobile phone includes a microphone that converts a user's voice into a voice signal, a speaker that emits the voice of the other party converted based on the received voice signal, and digital / analog of the voice signal. It has a converter for conversion. The communication unit 16 exchanges these audio signals using a communication function.

1-1-2. Functional Configuration of Orientation Estimation Device FIG. 3 is a diagram illustrating a functional configuration of the orientation estimation device 1 according to the first embodiment. By executing the program, the control unit 11 performs astronomical information acquisition unit 111, date and time information acquisition unit 112, position information acquisition unit 113, brightness information acquisition unit 114, posture information acquisition unit 115, absolute direction estimation unit 116, relative direction. It functions as the estimation unit 117 and the direction estimation unit 118.

  The astronomical information acquisition unit 111 acquires the astronomical information 121 from the storage unit 12. The date information acquisition unit 112 acquires date information from the clock unit 15. The position information acquisition unit 113 acquires position information from the communication unit 16. The lightness information acquisition unit 114 receives image data indicating the images Pa and Pb from the imaging unit 17 and acquires lightness information indicating the respective lightness. The posture information acquisition unit 115 acquires posture information from the posture detection unit 18.

  The absolute direction estimation unit 116 determines the absolute direction of the sun based on the celestial information 121 acquired by the celestial information acquisition unit 111, the date / time information acquired by the date / time information acquisition unit 112, and the position information acquired by the position information acquisition unit 113. presume. The absolute direction of the sun is the direction of the sun in the horizon coordinate system with the position of the azimuth estimation device 1 indicated by the position information as the origin, and is represented by, for example, an azimuth angle A and an altitude h.

  FIG. 4 is a schematic diagram showing a horizon coordinate system in which the position of the azimuth estimation apparatus 1 is the origin O. As shown in the figure, the direction of the sun Sn is expressed as a position on the celestial sphere in the horizon coordinate system. Here, the azimuth A is an angle formed by a great circle passing through the zenith and the sun Sn and a meridian, and is measured from true north to east. The altitude h is an angle from the horizon to the sun Sn along the great circle.

  In the celestial body information 121, information indicating movements such as rotation and revolution of solar system celestial bodies including the earth is described. Based on the astronomical information 121, the absolute direction estimation unit 116 represents the movement of the sun with respect to the earth, for example, in an equator coordinate system. Then, the absolute direction estimation unit 116 specifies the date and time based on the acquired date and time information, and calculates the position of the sun in the equator coordinate system at the specified date and time. Then, based on the acquired position information, the absolute direction estimation unit 116 determines the latitude and longitude of the azimuth estimation device 1, and the position of the sun Sn in the equator coordinate system is represented by the determined latitude and longitude. Convert to a horizontal coordinate system with the position as the origin O. Note that the celestial body information 121 may be a function in which the motion of the sun with respect to the earth is expressed in a predetermined celestial coordinate system with the date and position as independent variables, and for each combination of a plurality of dates and times and positions, It may be a table in which movement information such as the coordinates and speed of the sun is associated with.

  The relative direction estimation unit 117 estimates the relative direction of the sun based on the brightness information acquired by the brightness information acquisition unit 114. The relative direction of the sun is the relative direction of the sun with reference to the azimuth estimation device 1, and is the direction of the sun in the device coordinate system described above.

  FIG. 5 is a diagram for explaining the relative direction of the sun. In the same figure, the azimuth estimation device 1 is located at the origin O, and the image capturing direction by the image capturing unit 17 is directed to the arrow z (+) direction. Assuming that the angle between the line connecting the sun Sn and the origin O and the z (+) direction is ψ, the line Cv shown in FIG. It is a line connecting each intersection with the spherical surface.

  The sunlight itself obtained by directing the imaging direction to the sun (ψ = 0 degrees) includes light of all polarization components. Moreover, since reflected light of sunlight can be obtained even when the imaging direction is directed in the direction opposite to the sun (ψ = 180 degrees), the light obtained includes light of any polarization component. On the other hand, it is known that sunlight scattered by the atmosphere (hereinafter referred to as scattered light) has a polarization characteristic along a line Cv shown in FIG. Therefore, as the value of ψ which is the imaging direction approaches 90 degrees, the proportion of the polarization component along the line Cv in the light received by the imaging unit 17 becomes stronger than the proportion of the polarization component perpendicular to the line Cv. The intensity of light of the polarization component (hereinafter referred to as light intensity) has a correlation with the brightness of the image generated by the imaging unit 17 when the polarization component is received. That is, as the value of ψ approaches 90 degrees, each polarization component The difference in brightness of the images corresponding to (hereinafter referred to as brightness difference) increases.

  FIG. 6 is a diagram illustrating a change in brightness difference with respect to an angle formed by an imaging direction with respect to the sun direction. The horizontal axis is the value of the angle ψ, and the vertical axis is the brightness difference or an index value according to the brightness difference (for example, a quadratic function or a logarithmic function of the brightness difference). Thus, the lightness difference increases as the value of ψ is closer to 90 degrees. For example, when sunlight is irradiated from the side to the azimuth estimation apparatus 1 that captures the direction along the horizontal plane, the imaging direction From the front side, a polarization component in the direction perpendicular to the ground plane is obtained, and a polarization component in the horizontal direction with respect to the ground plane is difficult to obtain. For this reason, the closer the polarization direction of the polarizing filter is to the vertical direction with respect to the ground plane, the brighter the captured image is when the sunlight is irradiated from the side along the ground plane. The captured image becomes darker as it approaches the horizontal direction with respect to the plane. This tendency becomes stronger as the angle ψ formed by the imaging direction with respect to the sun direction approaches 90 degrees. Such polarization characteristics of sunlight are described in the program, and the relative direction estimation unit 117 calculates a brightness difference from the acquired brightness information, and estimates the corresponding angle ψ as the relative direction of the sun.

  Returning to FIG. The posture information acquisition unit 115 obtains an angle formed by the direction of gravity and the z-axis of the apparatus coordinate system from the posture information acquired from the posture detection unit 18, and specifies the elevation angle φ shown in FIG. The elevation angle φ is an angle formed by the imaging direction (that is, the z (+) direction) with the ground plane. That is, the attitude information acquisition unit 115 is an example of an attitude information acquisition unit that acquires attitude information indicating the attitude of the own apparatus (azimuth estimation apparatus 1) based on a certain direction. In this case, the certain direction is the direction of gravity (G in FIG. 4) or the normal direction of the ground plane.

  The azimuth estimation unit 118 is based on information indicating the absolute direction of the sun estimated by the absolute direction estimation unit 116, information indicating the relative direction of the sun estimated by the relative direction estimation unit 117, and the acquired posture information. The azimuth | direction of the azimuth | direction estimation apparatus 1 is estimated from the elevation angle which the information acquisition part 115 specified. Specifically, the azimuth estimation unit 118 acquires the azimuth angle A and altitude h as information indicating the absolute direction of the sun, acquires the angle ψ as information indicating the relative direction of the sun, and the elevation angle in the imaging direction as posture information. Get φ. Then, the azimuth estimation unit 118 identifies the z axis that satisfies the elevation angle φ with respect to the ground plane and the angle ψ with respect to the sun irradiation direction, and in which direction the identified z axis is in the horizon coordinates The azimuth angle θ indicating the angle is obtained with reference to the azimuth angle A indicating the absolute direction of the sun and the altitude h.

1-2. Operation Next, the operation of direction estimation by the direction estimation device 1 of the first embodiment will be described.
The user determines the z-axis that is the imaging direction and points the optical member 171 of the imaging unit 17 of the orientation estimation apparatus 1. On the display unit 14, two images Pa and Pb captured by the imaging unit 17 are displayed. The image Pa is an image captured through the optical member 171a, and the image Pb is an image captured through the optical member 171b. Therefore, the image Pa is an image generated by receiving polarized light having the direction component Da, and the image Pb is an image generated by receiving polarized light having the direction component Db. Therefore, when the direction component Da decreases in the light from the imaging direction, the image Pa becomes dark, and when the direction component Db decreases, the image Pb becomes dark.

  When the user rotates the azimuth estimation apparatus 1 around the determined z axis, the brightness difference between the two images Pa and Pb varies. The control unit 11 acquires brightness information of each image from the imaging unit 17 (brightness information acquisition unit 114), and stores the brightness difference in the RAM when the brightness difference has increased most.

  The control unit 11 estimates the angle ψ from the brightness difference stored in the RAM (relative direction estimation unit 117). FIG. 7 is a diagram exemplifying two images when the above-described brightness difference has increased most. As shown in FIG. 7A, when there is no brightness difference between the images Pa and Pb, the angle ψ indicating the relative direction of the sun is 0 degree or 180 degrees. That is, in the case of imaging toward the sun or when imaging with the back to the sun, each optical member 171 of the imaging unit 17 emits not only the scattered light of sunlight but also direct light or reflected light. Since the light is received, the received light has little polarization, and there is no difference in brightness between the two captured images Pa and Pb.

  On the other hand, as shown in FIGS. 7B to 7D, as the angle ψ increases to 30 degrees, 60 degrees, and 90 degrees, or decreases to 150 degrees, 120 degrees, and 90 degrees and approaches 90 degrees, The brightness difference between the images Pa and Pb increases. Since the relationship between the brightness difference and the angle ψ as shown in FIG. 6 is described in advance in the program, the control unit 11 estimates the angle ψ from the acquired brightness difference by executing this program. . At this stage, the control unit 11 may estimate two types of angles ψ (for example, 30 degrees and 150 degrees).

  Further, the control unit 11 acquires date and time information (date and time information acquisition unit 112) from the clock unit 15 and position information (position information acquisition unit 113) from the communication unit 16 and stores the astronomical information stored in the storage unit 12. 121 (the celestial body information acquisition unit 111) estimates the position of the sun in the horizon coordinates with the origin of the position of the azimuth estimation device 1 indicated by the acquired position information as the absolute direction at the date and time indicated by the acquired date and time information. (Absolute direction estimation unit 116).

  The control unit 11 acquires posture information from the posture detection unit 18 (posture information acquisition unit 115), the acquired posture information (elevation angle φ), the estimated relative direction of the sun (angle ψ), and the absolute direction (azimuth angle). From A and altitude h), the imaging direction of the azimuth estimation device 1 is specified, its azimuth angle θ (see FIG. 4) is calculated, and the position of the azimuth estimation device 1 is defined as the origin based on the calculated azimuth angle θ. The azimuth in the horizontal coordinate to be estimated is estimated (azimuth estimation unit 118), and a compass diagram corresponding to the azimuth is displayed on the display unit 14.

  The imaging direction (z (+) direction) in which the angle formed with the sun direction is an angle ψ and the angle formed with the ground plane is the elevation angle φ is a side surface of a cone having the origin O as an apex and an axis in the solar direction. In this case, since it is on a line intersecting the side surface of the cone having the origin O as an apex and having an axis in the zenith direction, one may be specified, but two may be specified. In this case, the control unit 11 estimates the two azimuth angles θ representing these azimuths using the two specified imaging directions as candidates, and displays compass diagrams based on the two azimuth angles θ estimated on the display unit 14. It may be displayed.

  With the above configuration, the azimuth estimation apparatus 1 according to the first embodiment can estimate the azimuth without using geomagnetism or GPS.

2. Second Embodiment An azimuth estimation apparatus 1 according to a second embodiment of the present invention will be described. In the second embodiment, description of matters common to the first embodiment is omitted. The azimuth estimation apparatus 1 according to the second embodiment is characterized in that, as information indicating the relative direction of the sun, the direction orthogonal to the direction of the strongest polarization component among the light received by the imaging unit 17 is specified with reference to the ground plane. This is different from the first embodiment.

2-1. Configuration The configuration of the azimuth estimation apparatus 1 according to the second embodiment is the same as the configuration of the azimuth estimation apparatus 1 according to the first embodiment, and is part of the function realized by the control unit 11 executing the program. There is a difference.
FIG. 8 is a diagram illustrating a functional configuration of the azimuth estimation apparatus 1 according to the second embodiment. The control unit 11 executes the program, so that the astronomical information acquisition unit 111, the date / time information acquisition unit 112, the position information acquisition unit 113, the brightness information acquisition unit 114, the posture information acquisition unit 115, which are common to the first embodiment, and In addition to functioning as an absolute direction estimation unit 116, it functions as a relative direction estimation unit 117a and a direction estimation unit 118a described later.

  The relative direction estimation unit 117a estimates the relative direction of the sun based on the lightness information acquired by the lightness information acquisition unit 114 and the posture information acquired by the posture information acquisition unit 115. In 2nd Embodiment, the relative direction of the sun is calculated | required as a position on the celestial sphere which the azimuth | direction estimation apparatus 1 exists in the center of a ground plane. For example, when a line is drawn with respect to this celestial sphere in the direction specified by the strongest polarization component of the light received by the imaging unit 17 (hereinafter referred to as a specific direction), a concentric circle centered on the sun is drawn (FIG. 5). In the above celestial sphere, the sun is located on an orthogonal line orthogonal to the line drawn in this specific direction. In other words, in the above celestial sphere, the direction from one point on the line drawn in the specific direction to an orthogonal line passing through the point and orthogonal to the line is the relative direction of the sun. The relative direction estimation unit 117a refers to the posture information acquired by the posture information acquisition unit 115 in order to estimate the relative direction of the sun based on the ground plane.

  FIG. 9 is a diagram illustrating that the relative direction estimation unit 117a according to the second embodiment estimates the relative direction of the sun. As shown in the figure, the relative direction estimation unit 117a identifies the angle formed by the specific direction and the direction component Db based on the two images Pa and Pb captured by the image capturing unit 17, and thereby the relative direction of the sun. Is estimated.

  For example, as illustrated in FIG. 9A, when the lightness of the image Pa is darker than the lightness of the image Pb, the light received by the image capturing unit 17 from the image capturing direction has the direction component Db more than the linearly polarized light having the direction component Da. It can be seen that it contains a lot of linearly polarized light. Accordingly, the angle formed by the direction component Db, that is, the x-axis direction and the line Cv along the specific direction in the celestial sphere is estimated to be at least less than 45 degrees. Furthermore, for example, when a condition such that the brightness difference between the image Pa and the image Pb exceeds a threshold is satisfied, the angle formed by the direction component Db and the line Cv is estimated to be 0 degree.

  As shown in FIG. 9B, when the brightness of the image Pa is substantially the same as the brightness of the image Pb, the light received by the imaging unit 17 from the imaging direction is linearly polarized light having the direction component Da and the direction component Db. It can be seen that it contains linearly polarized light having a substantially equal ratio. Therefore, the angle formed by the direction component Db (x-axis direction) and the line Cv is estimated to be approximately 45 degrees.

  Further, as shown in FIG. 9C, when the brightness of the image Pa is brighter than the brightness of the image Pb, the light received by the imaging unit 17 from the imaging direction has a direction component Da more than linearly polarized light having the direction component Db. It can be seen that it contains a lot of linearly polarized light. Therefore, the angle formed by the direction component Db and the line Cv is estimated to exceed 45 degrees. Furthermore, for example, when a condition such that the brightness difference between the image Pa and the image Pb exceeds a threshold is satisfied, the angle formed by the direction component Db and the line Cv is estimated to be 90 degrees.

  As described above, when the angle formed by the direction component Db and the line Cv is estimated from the brightness difference pattern of the images Pa and Pb, the relative direction estimation unit 117a refers to the posture information acquired by the posture information acquisition unit 115, and A direction orthogonal to the line Cv is estimated with reference to the ground plane. That is, the relative direction estimation unit 117a obtains the inclination of the directional component Db that is the x-axis direction with respect to the ground plane by referring to the posture information, and further, the angle formed by the direction component Db and the line Cv, the obtained inclination, Based on the above, the direction orthogonal to the above-mentioned line Cv when the ground plane is used as a reference is estimated. In addition, although the direction orthogonal to the line Cv is estimated on the basis of the horizon, the relative direction estimation unit 117a does not specify the relationship between this direction and the azimuth in the horizon coordinate system. That is, the “direction perpendicular to the line Cv” estimated as the relative direction of the sun by the relative direction estimation unit 117 a is a direction based on the direction estimation device 1.

  The azimuth estimation unit 118a is based on information indicating the absolute direction of the sun estimated by the absolute direction estimation unit 116 and information indicating the relative direction of the sun estimated by the relative direction estimation unit 117a. Is estimated. That is, the azimuth estimating unit 118a estimates the relationship between the relative direction of the sun and the azimuth in the horizon coordinate system using the absolute direction of the sun. Specifically, the azimuth estimation unit 118a is azimuthally oriented so that the position of the sun indicated by the absolute direction of the sun exists on a line drawn in the “direction perpendicular to the line Cv” indicated by the relative direction of the sun. The azimuth | direction when the estimation apparatus 1 is arrange | positioned is estimated.

2-2. Operation Next, the operation of direction estimation by the direction estimation device 1 according to the second embodiment will be described.
The user determines the z-axis that is the imaging direction and points the optical member 171 of the imaging unit 17 of the orientation estimation apparatus 1. FIG. 10 is a diagram illustrating an apparatus coordinate system with respect to the ground plane. In the second embodiment, the orientation of the orientation estimation device 1 is adjusted by the user so that the x (+) direction of the device coordinate system is included in the ground plane. For example, when the control unit 11 of the azimuth estimation apparatus 1 refers to the posture information detected by the posture detection unit 18 and determines that the x (+) direction is not included in the ground plane, the control unit 11 notifies the display unit 14 to that effect. A warning is given and the direction estimation operation is suspended until the orientation of the direction estimation device 1 is adjusted by the user. Note that the x (+) direction being included in the horizontal plane means that the angle formed by the x (+) direction and the horizontal plane does not exceed a threshold (for example, 2 degrees). Therefore, as shown in the figure, the angle formed by the x (+) direction and the gravity direction G is approximately 90 degrees (for example, 88 to 92 degrees), and the horizontal plane of the direction component Db that is the x-axis direction. The inclination with respect to is approximately 0 degrees (for example, ± 2 degrees).

FIG. 11 is a diagram for explaining the relative direction of the sun estimated by the relative direction estimation unit 117a. When the angle formed by the direction component Db and the line Cv is estimated to be 0 degrees from the brightness difference pattern of the captured images Pa and Pb as shown in FIG. 9A, the relative direction estimation unit 117a As shown in FIG. 11A, a line L ₁ perpendicular to the tangent line T ₁ parallel to the x axis is specified at a point z where the celestial sphere and the z axis intersect. There are an infinite number of lines Cv passing through the point z and forming a specific angle with the direction component Db, but the tangent at the point z of these lines Cv is only the tangent T ₁ shown in FIG. The tangent line T ₁ is included in a plane defined by the x axis and the z axis (hereinafter referred to as the xz plane) because the angle formed by the direction component Db and the line Cv is 0 degree. Since the line L ₁ orthogonal to the tangent line T ₁ at the point z is also orthogonal to the line Cv at the point z, the relative direction estimation unit 117a converts the line L ₁ orthogonal to the tangent line T _{1 at the} point z Estimated as relative direction.

In addition, when the angle formed by the direction component Db and the line Cv is estimated to be 45 degrees as shown in FIG. 9B, the relative direction estimation unit 117a has the above-mentioned points as shown in FIG. In z, a tangent line T ₂ having an angle of 45 degrees with the xz plane is specified, and a line L ₂ perpendicular to the tangent line T ₂ is specified as the relative direction of the sun. In this way, the relative direction estimation unit 117a identifies the line L (L ₁ , L ₂ ) on the celestial sphere according to the angle formed by the direction component Db and the line Cv, and determines the direction along this relative to the sun. Estimated as direction.

Then, the azimuth estimation unit 118a specifies the imaging direction (z (+) direction) of the azimuth estimation device 1 from the estimated relative direction (line L) and absolute direction (azimuth angle A and altitude h) of the sun, The azimuth angle θ is calculated.
FIG. 12 is a diagram for explaining the azimuth angle θ in the imaging direction calculated by the azimuth estimation apparatus 1. The azimuth estimation unit 118a acquires the absolute direction estimated by the absolute direction estimation unit 116, that is, the azimuth angle A and altitude h of the sun in the horizon coordinate system with the position of the azimuth estimation device 1 as the origin. Then, as shown in FIG. 11 (a), when the relative direction estimation unit 117a has estimated the line L ₁ as the relative direction of the sun, direction estimation unit 118a passes the line L _1, and advanced from the horizon The position of h is specified as the position of the sun Sn. For example, as shown in FIG. 12A, the azimuth estimation unit 118a identifies a curve Lh connecting points on the celestial sphere located at a position of altitude h from the horizon, and this curve Lh and the line L The intersection with ₁ is specified as the position of the sun Sn. Then, the azimuth estimating unit 118a identifies the azimuth indicating north based on the identified position of the sun Sn and the azimuth angle A, and calculates the azimuth angle θ in the imaging direction with reference to the north.

Similarly, as shown in FIG. 11 (b), when the relative direction estimation unit 117a has estimated the line L ₂ as the relative direction of the sun, as shown in FIG. 12 (b), the orientation estimating section 118a is The position of the altitude h from the horizon passing through the line L ₂ is specified as the position of the sun Sn. Then, the azimuth estimating unit 118a identifies the azimuth indicating north based on the identified position of the sun Sn and the azimuth angle A, and calculates the azimuth angle θ in the imaging direction with reference to the north.

  As described above, when the azimuth estimation unit 118a calculates the azimuth angle θ in the imaging direction, it estimates the azimuth in the horizon coordinates with the position of the azimuth estimation device 1 as the origin based on the calculated azimuth angle θ, and the azimuth A compass diagram corresponding to is displayed on the display unit 14.

In addition, as shown in FIG. 12, two points may be specified as the intersection between the curve Lh and the line L (L ₁ , L ₂ ). In this case, the control unit 11 estimates the azimuth angle θ based on the two specified points as the sun position candidates, and displays a compass diagram based on the two azimuth angles θ estimated on the display unit 14. Each may be displayed.

  With the above configuration, the azimuth estimation apparatus 1 according to the second embodiment can estimate the azimuth without using geomagnetism or GPS.

3. Modification The above is the description of the embodiment, but the contents of this embodiment can be modified as follows. Further, the following modifications may be combined.
3-1. In the first embodiment described above, the user rotates the azimuth estimation apparatus 1 about the z-axis, but may rotate each optical member 171 of the imaging unit 17. This rotation may be performed by a driving unit (not shown) controlled by the control unit 11.

  The control unit 11 may rotate each optical member 171 of the imaging unit 17 according to the inclination of the apparatus coordinate system with respect to the ground plane with reference to the posture information detected by the posture detection unit 18. Thereby, the azimuth estimation device 1 can link the direction component Da and the direction component Db of the polarization filter with the directions of the y-axis and the x-axis.

3-2. In the above-described embodiment, two optical members 171 are provided in the imaging unit 17, but three or more optical members 171 may be provided, or only one may be provided. When only one optical member 171 is provided in the imaging unit 17, the optical member 171 is configured to be periodically rotated by the drive unit, and the control unit 11 has a plurality of predetermined numbers within the rotation cycle. The relative direction of the sun may be estimated by performing image capturing at the timing of and comparing the brightness of the image according to each timing.

3-3. In the above-described embodiment, the angle formed by the polarization directions of the polarizing filters provided on the optical member 171a and the optical member 171b is 90 degrees, but this angle is not limited to 90 degrees. There is a difference in the polarization direction of each polarizing filter, and the two need not be parallel.

3-4. In the first embodiment described above, the control unit 11 acquires the brightness information of two images obtained by rotating the azimuth estimation apparatus 1 or the optical member 171. When the brightness difference increases most, the brightness difference is obtained. In the RAM, the angle ψ that is the relative direction of the sun was estimated from the stored brightness difference, but the brightness information of the two images obtained without rotating the azimuth estimation device 1 or the optical member 171 was acquired, The angle ψ may be estimated based on the brightness difference. In this case, the direction of the line Cv connecting the z (+) directions shown in FIG. 5 may not coincide with any of the direction components Da and Db corresponding to the two images Pa and Pb, respectively. For example, FIG. 9B described above is a diagram illustrating an example of the brightness difference between two images in this modification. As shown in the figure, when both the angles formed by the line Cv with respect to the direction components Da and Db are 45 degrees, the amounts of the polarization components absorbed by the optical members 171a and 171b are equal to each other. Both Pb become dark and no brightness difference occurs. Even in such a case, the control part 11 should just estimate the relative direction of the sun with the following methods.

(1) When the program describes the relationship between the angle ψ and the maximum brightness difference, as well as the relationship between the brightness itself and the angle ψ, the control unit 11 calculates the brightness itself of each image and the calculated brightness difference. The key ψ may be specified from these patterns described in the program.

(2) The control unit 11 specifies the x-axis or y-axis direction of the apparatus coordinate system from the posture information acquired by the posture information acquisition unit 115, and the specified x-axis or y-axis direction and the relative direction of the sun Sn And the angle ψ may be corrected in accordance with the inclination. Specifically, this processing is as follows. The control unit 11 calculates the angle ψ, which is the relative direction of the sun, assuming that the brightness difference between the images is the maximum brightness difference. Then, the control unit 11 calculates the azimuth angle θ in the imaging direction from the relative direction of the sun, the absolute direction of the sun, and the elevation angle φ obtained from the posture information. Next, the control unit 11 specifies the x (+) direction or the y (+) direction of the apparatus coordinate system with respect to the gravity direction from the posture information, and specifies the specified direction and the z (+) direction illustrated in FIG. An angle ζ formed with the direction of the connecting line Cv is obtained. Then, the angle ψ is corrected so that the angle ζ is reduced, and the above calculation is repeated. Note that various optimization calculation algorithms can be applied to this processing.

(3) The imaging unit 17 may further include an optical member 171c that does not have a polarizing filter, and may capture an image Pc captured through the optical member 171c. Since the image Pc is an image generated by light that has not passed through the polarizing filter, the influence on the brightness of the image through the polarizing filter is specified by comparing with the image Pa and the image Pb. Thereby, in addition to the lightness difference obtained by comparing the lightness between the image Pa and the image Pb, the lightness difference between the image Pa and the image Pb with respect to the image Pc is specified, thereby improving the accuracy of the direction estimation.

3-5. In the above-described embodiment, the imaging unit 17 has the imaging direction only in the z (+) direction, but may have a plurality of imaging directions. In this case, a plurality of optical members 171 may be provided in each of a plurality of imaging directions, and each optical member 171 may be provided with a polarizing filter having a different polarization direction. Thereby, the azimuth estimation apparatus 1 has images Pa and Pb obtained by imaging the z (+) direction and a direction different from the z (+) direction (for example, 1 from the z (+) direction to the x (+) direction in the xz plane). The images Pc and Pd obtained by imaging the direction misaligned) are acquired. Then, the direction estimation apparatus 1 uses the angle ψc and the line Lc estimated from the set of the images Pc and Pd when the angle ψa and the line La estimated from the set of the images Pa and Pb cannot be narrowed down to one. These may be narrowed down to one. The imaging direction is not limited to two or less, and may be three or more.

  The reason why the relative direction of the sun cannot be narrowed down to one is that the specific direction is symmetric with respect to the irradiation direction of sunlight. For example, when the sun is located on the west horizon, when imaging the horizon in the northwest (direction 45 degrees from west to north), and in the southwest (direction 45 degrees from west to south) In both cases, the specific direction is perpendicular to the horizon, and the angle shifted from the west, which is the irradiation direction of sunlight, is equal to 45 degrees. As in the above-described modification, when there are two or more candidates for the relative direction of the sun specified by the image captured in the first imaging direction, the second imaging that is different from the first imaging direction In some cases, one of the two or more candidates can be selected by using an image obtained by imaging the direction.

(1) Specifically, according to the above example, when the azimuth estimation device 1 images the southeast and the direction deviated 10 degrees clockwise from the southeast as viewed from the zenith, the latter is more preferable than the former. However, the brightness difference increases. The latter is because the direction is 55 degrees from south to east. On the other hand, when the azimuth estimation device 1 images the southwest and the direction shifted 10 degrees clockwise from the southwest as viewed from the zenith, the brightness difference is lower in the latter than in the former. The latter is because the direction is 35 degrees from south to west. Therefore, when a certain direction and a direction deviated from a certain direction are imaged, it is determined whether the lightness difference in the deviated direction is larger or smaller than the lightness difference in the certain direction. By doing so, the azimuth estimation device 1 can narrow down this certain direction to one.

(2) In addition, by causing the user to change the orientation of the azimuth estimation device 1 or to move the direction of the optical member 171 of the imaging unit 17 by a driving unit (not shown), the imaging unit 17 can have a different imaging direction. You may make it image-capture and the direction estimation apparatus 1 may acquire the image which imaged the several imaging direction. The control unit 11 of the azimuth estimation apparatus 1 may narrow down the relative direction of the sun to one by comparing the images in the plurality of imaging directions obtained in this way. Even in this case, since the posture only changes, it is not necessary to move the position (for example, the center of gravity) of the azimuth estimation apparatus 1 from the origin O. And compared with the case where a several direction is imaged simultaneously, the number of parts of the direction estimation apparatus 1 can be suppressed.

3-6. In the above-described embodiment, the two optical members 171a and 171b of the imaging unit 17 are provided with polarization filters having different polarization directions, but one optical member 171 is provided with a plurality of types of polarization filters having different polarization directions. It may be done.

(1) FIG. 13 is a diagram showing an example of a polarizing filter in this modification. As shown in FIG. 13A, the polarizing filter is divided into a plurality of regions by a plurality of lines parallel to the y-axis direction, and the plurality of divided regions are configured to have different polarization directions alternately. ing. By using this polarizing filter, as shown in FIG. 13B and FIG. 13C, a brightness difference is generated in each region according to the received polarization component, and the captured image is bright and dark for each region. Pattern occurs. The pattern shown in FIG. 13B is bright at both ends in the x-axis direction, and the pattern shown in FIG. 13C is dark at both ends in the x-axis direction. Thus, it is only necessary to identify the received polarization component from the pattern difference and to estimate the relative direction of the sun based on the estimation result. In this case, the number of optical members 171 may be one.

(2) Moreover, FIG. 14 is a figure which shows another example of the polarizing filter in this modification. As shown in FIG. 14A, this polarizing filter is a regular octagon, and is divided into eight regions R1 to R8 by eight line segments connecting the center of the regular octagon and each vertex. The region R1 and the region R5 are polarizing filters having a polarization direction parallel to the x (+) direction. The region R3 and the region R7 are polarization filters having a polarization direction parallel to the y (+) direction. The regions R2 and R6 are polarizing filters having a polarization direction of −45 degrees with respect to the x (+) direction, and the regions R4 and R8 are +45 degrees with respect to the x (+) direction. A polarization filter having a polarization direction. Thus, the polarizing filter shown in FIG. 14 is partitioned into regions each having four types of polarization directions.

  As shown in FIG. 14B, the image captured through the polarizing filter described above is “region R1 and region R5 are the darkest, region R2 and region R6, and region R4 and region R8 are the next darkest, When the pattern of “R3 and region R7 is brightest” is shown, the direction (specific direction) of the strongest linearly polarized light received by the direction estimation device 1 from this imaging direction is a direction parallel to the y-axis direction. Therefore, as shown in FIG. 14B, it can be seen from this pattern that the above-described line Cv is arranged in a direction parallel to the y-axis direction. That is, for example, a line connecting the centers of gravity of the region R1 and the region R5 overlaps the line Cv described above.

  Further, as shown in FIG. 14C, the image picked up through the polarizing filter is “region R4 and region R8 are the darkest, region R1 and region R5, and region R3 and region R7 are the next darkest. , The direction of the strongest linearly polarized light (specific direction) received by the azimuth estimation apparatus 1 from this imaging direction is −45 with respect to the x (+) direction. The direction of the degree. Therefore, as shown in FIG. 14B, it can be seen from this pattern that the above-described line Cv is arranged in the direction of −45 degrees with respect to the x (+) direction. That is, for example, a line connecting the centers of gravity of the region R4 and the region R8 overlaps the above-described line Cv.

  Further, as shown in FIG. 14C, the image picked up through the polarizing filter described above is “region R3 and region R7 are the darkest, region R2 and region R6, and region R4 and region R8 are the next darkest. When the pattern indicating that the region R1 and the region R5 are the brightest is indicated, the direction (specific direction) of the strongest linearly polarized light received from the imaging direction by the direction estimation device 1 is a direction parallel to the x-axis direction. Therefore, as shown in FIG. 14C, it can be seen from this pattern that the above-described line Cv is arranged in a direction parallel to the x-axis direction. That is, for example, a line connecting the centers of gravity of the region R3 and the region R7 overlaps the above-described line Cv.

  In this way, the polarization direction of the polarizing filter is increased from the two types of x and y axes to four types configured so that the phases are different by 45 degrees, so that the direction of the strongest linearly polarized light received from the imaging direction (specific Direction) can be improved. Furthermore, the precision of the azimuth | direction estimation by the azimuth | direction estimation apparatus 1 improves by making a phase difference fine and increasing the kind of polarization direction with which a polarizing filter is provided. In addition, the polarization direction with which a polarizing filter is provided is not limited to 2 types and 4 types, What is necessary is just two or more types. In the above-described example, the polarizing filter is a regular octagon, and the polarization directions of two opposing regions among the eight regions R1 to R8 partitioned by eight line segments connecting the center of the regular octagon and each vertex. However, the form of the polarizing filter is not limited to this, and when the polarizing filter is partitioned, for example, all the polarization directions of the partitioned areas may be different.

3-7. In the above-described embodiment, the lightness information acquisition unit 114 receives image data from the imaging unit 17 and acquires lightness information indicating the lightness. However, light intensity information indicating the light intensity of the polarization component instead of the lightness information. May be obtained from other configurations. For example, the azimuth estimation apparatus 1 may include a light intensity sensor that detects two light intensities obtained via two polarization filters, instead of the imaging unit 17. In this case, the brightness information acquisition unit 114 acquires the intensity of two lights from the light intensity sensor as light intensity information, and the relative direction estimation unit 117 estimates the angle ψ from the light intensity difference that is the difference between them. Good. In short, the azimuth estimation device 1 obtains light intensity information indicating each light intensity from detection means that separates sunlight irradiated on the device into a plurality of polarization components and detects the light intensity of each separated polarization component. It may be configured as possible.

  In the above-described embodiment, the lightness information acquisition unit 114 receives image data indicating the images Pa and Pb from the imaging unit 17 and acquires lightness information indicating the respective lightnesses. However, as described above, the polarization component Therefore, the brightness information acquired by the brightness information acquisition unit 114 is light indicating the light intensity of each polarization component. Used as intensity information. That is, the lightness information acquisition unit 114 separates the sunlight irradiated to the own device into a plurality of polarization components, and detects light intensity information indicating each light intensity from a detection unit that detects the light intensity of each separated polarization component. It functions as a light intensity information acquisition means for acquiring.

3-8. In the above-described embodiment, the imaging unit 17 includes the polarizing filter, but may include a liquid crystal instead of the polarizing filter. In this case, the control unit 11 controls the voltage applied to the liquid crystal to change the polarization characteristics of the liquid crystal, and the imaging unit 17 may perform imaging according to the changed polarization characteristics. That is, the control unit 11 functions as a liquid crystal control unit that changes the polarization component transmitted by the liquid crystal by changing the applied voltage.

3-9. In the above-described embodiment, the communication unit 16 identifies the position of the azimuth estimation device 1 by reading the identification information of the radio base station, and outputs position information indicating the position. Configurations other than the communication unit 16 May output position information. For example, a positioning unit using GPS may specify the position of the orientation estimation device 1. Even in this case, the user does not need to move the azimuth estimation apparatus 1 in order to estimate the azimuth.

3-10. Note that the azimuth estimation apparatus 1 may include a geomagnetic sensor. In this case, the azimuth estimation device 1 evaluates the reliability of the azimuth estimation by the geomagnetic sensor based on the sensor sensing result, and when the evaluation value indicating the evaluation falls below a predetermined threshold, the above azimuth You may make it display the azimuth | direction estimated by the estimation part 118. FIG. Further, when there are a plurality of azimuth estimation results by the azimuth estimation unit 118, an estimation result closer to the azimuth estimation result by the geomagnetic sensor may be displayed on the display unit 14, or the azimuth estimation by the geomagnetic sensor may be performed. The result itself may be displayed on the display unit 14.

3-11. In the above-described embodiment, a compass diagram representing the estimated orientation is displayed on the display unit 14 as shown in FIG. 2B. However, the display unit 14 displays parallel rays perpendicular to the ground plane. When the azimuth estimating apparatus 1 is in such a posture that the display surfaces are parallel, as described above, the orthographic projection of the compass diagram drawn on the ground plane cannot be displayed on the display unit 14. In this case, the display unit 14 may display the orientation in the direction opposite to the imaging direction (that is, the z (−) direction). For example, the display unit 14 may display a semicircle portion of the compass diagram viewed from the center point of the compass diagram, or may display a character string such as “northeast” or “southwest”.

3-12. Each program executed by the control unit 11 of the azimuth estimation apparatus 1 can be read by a computer device such as a magnetic recording medium such as a magnetic tape or a magnetic disk, an optical recording medium such as an optical disk, a magneto-optical recording medium, or a semiconductor memory. It can be provided in a state stored in a recording medium. It is also possible to download this program via a network such as the Internet. Various devices other than the CPU can be applied as the control means exemplified by the control unit 11. For example, a dedicated processor may be used.

3-13. In the above-described embodiment, the storage unit 12 stores the celestial information 121, and the celestial information acquisition unit 111 acquires the celestial information 121 from the storage unit 12. Astronomical information may be acquired from the configuration. Examples of other configurations include a server device that supplies astronomical information upon request. That is, the astronomical information acquisition unit 111 may transmit a request for astronomical information to the server device via the communication unit 16 and acquire the astronomical information requested from the server device. In this case, the storage unit 12 may not store the astronomical information 121.

3-14. In the first embodiment described above, the brightness difference information acquisition unit 114 acquires the brightness information of each image from the imaging unit 17 and stores the brightness difference in the RAM. However, instead of the brightness difference, the brightness difference of each image is stored. The ratio may be stored.

3-15. In the second embodiment described above, the orientation of the azimuth estimation device 1 has been adjusted by the user so that the x (+) direction of the device coordinate system is included in the ground plane. However, the orientation need not be adjusted. In this case, the control unit 11 of the azimuth estimation apparatus 1 refers to the posture information detected by the posture detection unit 18 to acquire the inclination with respect to the ground plane in the x (+) direction, and the direction component Db that is the x-axis direction. The angle of the line Cv with respect to the ground plane may be calculated by adding this inclination to the angle formed by the line Cv. Then, the relative direction estimation unit 117a may identify the line L on the celestial sphere based on the angle of the line Cv with respect to the ground plane and the elevation angle φ in the z (+) direction.

3-16. The relative direction estimation unit 117 of the first embodiment described above acquires the angle ψ, and the relative direction estimation unit 117a of the second embodiment acquires the line L that is orthogonal to the line Cv or the tangent line T at the point z, respectively. Although the relative direction of the sun has been estimated, the relative direction estimation unit 117 (117a) may acquire both the angle ψ and the line L to estimate the relative direction of the sun. The angle ψ clarifies the relative angle of the imaging direction with respect to the sunlight irradiation direction, and the line L clarifies the angle of the direction of light received from the imaging direction (specific direction) with respect to the ground plane. In combination, the relative direction of the sun can be estimated more accurately.

DESCRIPTION OF SYMBOLS 1 ... Direction estimation apparatus, 11 ... Control part, 111 ... Astronomical information acquisition part, 112 ... Date information acquisition part, 113 ... Position information acquisition part, 114 ... Brightness information acquisition part, 115 ... Attitude information acquisition part, 116 ... Absolute direction Estimating unit, 117 ... Relative direction estimating unit, 118 ... Direction estimating unit, 12 ... Storage unit, 121 ... Astronomical information, 13 ... Operation unit, 14 ... Display unit, 15 ... Clock unit, 16 ... Communication unit, 17 ... Imaging unit , 171 (171a, 171b) ... optical member, 18 ... attitude detection unit

Claims (8)

Celestial information acquisition means for acquiring celestial information indicating the movement of the sun with respect to the earth;
Date and time information acquisition means for acquiring date and time information;
Position information acquisition means for acquiring position information indicating the position of the own device;
Light intensity information acquisition means for acquiring light intensity information indicating each light intensity from detection means for separating the sunlight irradiated on the device into a plurality of polarization components and detecting the light intensity of each separated polarization component When,
Attitude information acquisition means for acquiring attitude information indicating the attitude of the own apparatus with reference to a certain direction;
With reference to the celestial information acquired by the celestial information acquisition means, the horizon with the position indicated by the position information acquired by the position information acquisition means as the origin at the date indicated by the date information acquired by the date information acquisition means. First estimating means for estimating the direction of the sun in coordinates;
A second method for estimating the direction of the sun with reference to the device according to each light intensity indicated by the light intensity information acquired by the light intensity information acquisition means and the attitude information acquired by the attitude information acquisition means; An estimation means;
Azimuth estimation means comprising: azimuth estimation means for estimating an azimuth in horizon coordinates with the position of the own apparatus as an origin in accordance with each direction estimated by the first estimation means and the second estimation means. apparatus. Celestial information acquisition means for acquiring celestial information indicating the movement of the sun with respect to the earth;
Date and time information acquisition means for acquiring date and time information;
Position information acquisition means for acquiring position information indicating the position of the own device;
Light intensity information acquisition means for acquiring light intensity information indicating each light intensity from detection means for separating the sunlight irradiated on the device into a plurality of polarization components and detecting the light intensity of each separated polarization component When,
Attitude information acquisition means for acquiring attitude information indicating the attitude of the own apparatus with reference to a certain direction;
With reference to the celestial information acquired by the celestial information acquisition means, the horizon with the position indicated by the position information acquired by the position information acquisition means as the origin at the date indicated by the date information acquired by the date information acquisition means. First estimating means for estimating the direction of the sun in coordinates;
Second estimating means for estimating the direction of the sun with reference to the device according to each light intensity indicated by the light intensity information acquired by the light intensity information acquiring means;
An azimuth that estimates the azimuth in the horizon coordinate with the position of the own device as the origin, according to each direction estimated by the first estimation means and the second estimation means and the attitude information acquired by the attitude information acquisition means An azimuth estimation apparatus comprising: an estimation means. The azimuth estimation apparatus according to claim 1, wherein the second estimation unit estimates the direction of the sun according to the difference in the light intensity. The detection means includes imaging means for imaging through a plurality of polarization filters having different polarization directions,
4. The light intensity information acquisition unit acquires, as the light intensity information, lightness information indicating the lightness of each image captured by the imaging unit through each of the polarizing filters. 5. The azimuth estimation apparatus according to 1. The detection unit includes an imaging unit that performs imaging through a filter in which a plurality of polarization filters having different polarization directions are arranged,
The azimuth according to any one of claims 1 to 3, wherein the light intensity information acquisition unit acquires lightness information indicating a lightness arrangement pattern of an image captured by the imaging unit as the light intensity information. Estimating device. The detection unit includes: an imaging unit that performs imaging through a polarizing filter; and a rotation driving unit that rotates the polarizing filter to change a polarization component that is transmitted to the imaging unit. The azimuth estimation apparatus according to any one of 3. The said detection means is provided with the imaging means which images through a liquid crystal, and the liquid crystal control means which changes the polarization component which the said liquid crystal permeate | transmits by changing the applied voltage. The azimuth estimation apparatus described. Storage means for storing astronomical information indicating the movement of the sun with respect to the earth, a clock for outputting date and time information, positioning means for measuring the position of the own apparatus and outputting position information indicating the position, and irradiation to the own apparatus A computer comprising: detection means for separating sunlight to be separated into a plurality of polarization components; detecting the light intensity of each of the separated polarization components; and attitude detection means for detecting the attitude of the device with respect to a certain direction. The
Celestial information acquisition means for acquiring the celestial information from the storage means;
Date and time information acquisition means for acquiring the date and time information from the clock;
Position information acquisition means for acquiring the position information from the positioning means;
Light intensity information acquisition means for acquiring light intensity information indicating each light intensity from the detection means;
Attitude information acquisition means for acquiring attitude information indicating the attitude of the device itself from the attitude detection means;
With reference to the celestial information acquired by the celestial information acquisition means, the horizon with the position indicated by the position information acquired by the position information acquisition means as the origin at the date indicated by the date information acquired by the date information acquisition means. First estimating means for estimating the direction of the sun in coordinates;
A second method for estimating the direction of the sun with reference to the device according to each light intensity indicated by the light intensity information acquired by the light intensity information acquisition means and the attitude information acquired by the attitude information acquisition means; An estimation means;
A program for functioning as an azimuth estimation unit that estimates an azimuth in horizon coordinates with the position of its own device as an origin according to each direction estimated by the first estimation unit and the second estimation unit.

Images