Floor surface state detection device, distance measurement device equipped with the same, floor surface state detection method, and floor surface state detection program

Abstract

To provide a floor surface condition detection device, a distance measuring device including the same, a floor surface condition detection method, and a floor surface condition detection program, which can accurately detect the condition of a floor surface.SOLUTION: A control section 10 is a device for detecting the condition of a floor surface FL on which an object 30 is placed, and comprises a distance calculation section 11 and an object detection section 18. The distance calculation section 11 calculates information on distance to the object 30 according to the amount of reflection of light emitted from a lighting device 21 toward the object 30. The object detection section 18 detects the condition of the floor surface FL on which the object 30 is placed on the basis of the distance information acquired by the distance calculation section 11.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to, for example, a floor surface state detection device that detects the state of a floor surface such as unevenness or obstacles on the floor surface, a distance measurement device equipped with the same, a floor surface state detection method, and a floor surface state detection program.

Background Art

[0002] In recent years, for example, a distance measurement device that generates a distance image including distance information to a measurement object for each pixel has been used by using a TOF (Time of Flight) sensor that receives reflected light of light irradiated from an LED (Light Emitting Diode) as a light source toward the measurement object and measures the distance to the measurement object. For example, Patent Document 1 discloses a coordinate calibration method for a human measurement system that configures the coordinate system of a distance image obtained by a depth camera into a laboratory coordinate system based on data of an indoor plane part included in the distance image.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above conventional human measurement system has the following problems. That is, although the above publication discloses a method for accurately analyzing the movements and postures of a human by calibrating the coordinate system of a distance image obtained by a depth camera into a laboratory coordinate system, the state of the floor surface where the human is located is not considered.

[0005] For example, when a depth camera detects a person while moving on the floor surface, it is very important to recognize the state of the floor surface on which it travels. An object of the present invention is to provide a floor surface state detection device capable of accurately detecting the state of a floor surface, a distance measurement device equipped with the same, a floor surface state detection method, and a floor surface state detection program.

Means for Solving the Problems

[0006] The floor surface state detection device according to the first invention is a floor surface state detection device that detects the state of a floor surface on which an object is placed, and includes a distance information acquisition unit and a state detection unit. An angle information acquisition unit, a three-dimensional coordinate conversion unit, a plane detection unit, a height calculation unit, a coordinate rotation calculation unit, a concavity and convexity detection unit, a threshold setting unit, The distance information acquisition unit acquires distance information to the object by receiving the reflected light of the electromagnetic wave irradiated from the lighting device to the object. and based on the phase difference between the reflected wave of the electromagnetic wave and the electromagnetic wave, The state detection unit detects the state of the floor surface on which the object is placed based on the distance information acquired by the distance information acquisition unit. The angle information acquisition unit acquires angle information corresponding to each pixel included in the distance image. The three-dimensional coordinate conversion unit converts the distance information acquired by the distance information acquisition unit into three-dimensional coordinates based on the angle information acquired by the angle information acquisition unit. The plane detection unit detects the floor surface on which the object is placed. The height calculation unit calculates the installation height of the distance measuring device based on the distance information on the floor surface detected by the plane detection unit and based on the three-dimensional coordinates converted by the three-dimensional coordinate conversion unit. The coordinate rotation calculation unit calculates a rotated coordinate obtained by rotating the three-dimensional coordinates converted from the distance information and the angle information in the three-dimensional coordinate conversion unit around an axis. The concavity and convexity detection unit compares the height-direction coordinate of the rotated coordinate calculated by the coordinate rotation calculation unit with the installation height calculated by the height calculation unit, and when detecting an object having a positive or negative dimension in the height direction, detects the object as a concavity and convexity on the floor surface. The threshold setting unit sets first, second, and third thresholds as predetermined thresholds used when detecting concavity and convexity in the concavity and convexity detection unit. Then, the height calculation unit calculates the average value of the coordinate values in the optical axis direction of a plurality of coordinate values obtained again by rotating the orthogonal coordinate system of the distance measuring device around the axis by the angle formed by the perpendicular line of the floor surface detected by the plane detection unit and the optical axis of the distance measuring device as the installation height, and the concavity and convexity detection unit determines that there is an object on the floor surface when the dimension in the height direction from the floor surface is larger than the first threshold, determines that there is a hole in the floor surface when the dimension in the height direction from the floor surface is smaller than the second threshold, and determines that there is a slope on the floor surface when the amount of change in the dimension in the height direction from the floor surface of adjacent pixels is larger than the third threshold.

[0007] Here, for example, using the distance information to the object acquired from a TOF (Time-of-Flight) sensor that measures the distance to the measurement object by receiving the reflected light of the light irradiated from an LED (Light emitting diode) as a light source toward the object, the state of the floor surface is detected. Here, the detected state of the floor surface includes, for example, recesses such as holes formed in the floor surface, protrusions such as obstacles placed on the floor surface, and the like.

[0008] This floor surface state detection device may be provided, for example, inside a distance measurement device such as a TOF sensor, or may be provided outside the distance measurement device. The electromagnetic wave irradiated from the lighting device includes, for example, light in a broad sense (ultraviolet light, visible light, infrared light), γ (gamma) rays with a wavelength shorter than light, X-rays, microwaves with a wavelength longer than light, radio waves for broadcasting (short waves, medium waves, long waves), ultrasonic waves, elastic waves, quantum waves, and the like.

[0009] Note that the distance information acquisition unit may be configured to detect the reflection of electromagnetic waves and calculate the distance information, or may be configured to acquire the distance information from, for example, a distance sensor provided as an external device. Thereby, for example, even when the distance measuring device is mounted on a transport device or the like capable of traveling on the floor surface, the state of the traveling floor surface can be detected, so that operations such as conveyance can be performed while avoiding unevenness such as holes and obstacles. As a result, the state of the floor surface can be accurately detected, and operations such as conveyance can be efficiently performed. In addition, since concavities and convexities such as holes and obstacles formed on the floor surface can be accurately detected, operations such as conveyance can be efficiently performed. Furthermore, for example, in a configuration in which the distance measuring device includes, as a light receiving unit, a light receiving lens and an imaging element that detects the amount of electromagnetic waves received through the light receiving lens, the angle with respect to the subject is determined for each pixel of the imaging element by the light receiving lens, so that angle information corresponding to each pixel can be acquired. In addition, the distance information can be converted into three-dimensional coordinates (X, Y, Z) using the angle information corresponding to each pixel. Also, as a preliminary step to detecting the unevenness actually formed on the floor surface, by detecting the floor surface, when detecting the presence or absence of an object, the distance (height) from the floor surface to the distance measuring device can be used as a reference value. Also, when calculating the installation height of the distance measuring device from the position of the floor surface and detecting the unevenness of the floor surface, the distance (height) from the floor surface to the distance measuring device can be used as a reference value. Also, regarding the distance to the floor surface measured by the distance measuring device, by rotating the orthogonal coordinate system of the distance measuring device around the axis by the angle formed between the perpendicular to the floor surface and the optical axis of the distance measuring device, the coordinate value in the optical axis direction of the coordinate value obtained again can be calculated as the installation height of the distance measuring device. That is, for example, by rotating around the axis by the angle formed between the perpendicular to the floor surface and the optical axis of the distance measuring device so that the Z-axis corresponding to the optical axis of the distance measuring device faces the vertical direction, the installation height can be calculated so as to obtain distance information equivalent to the case where the distance measuring device irradiates light directly downward and receives the reflected light. Also, by obtaining the average value of the coordinate values (distances) from the plane recognized as the floor surface and calculating this average value as the installation height, for example, even when there are minute unevenness or the like on the floor surface, the installation height of the distance measuring device from the floor surface can be accurately calculated. Also, when actually detecting the state of the floor surface, by calculating the rotation coordinates obtained by rotating the three-dimensional coordinates converted from the distance information and the angle information in the three-dimensional coordinate conversion unit around the axis, the presence or absence of unevenness on the floor surface can be detected. That is, by using the calculated rotation coordinates, it is possible to measure the distance in the height direction (depth of the hole, height of the obstacle, etc.) measured in a state of looking directly from above the unevenness substantially. Also, by comparing the installation height to the floor surface and the height of the object (coordinate in the height direction), it is possible to easily detect whether there is unevenness on the floor surface according to whether there is a change in the dimension in the height direction with respect to the surface of the floor. Also, when detecting the state (unevenness, etc.) of the floor surface, when comparing the installation height to the floor surface and the height of the unevenness (coordinate in the height direction), if the difference in height is greater than or less than a predetermined threshold value, by detecting the object as the unevenness of the floor surface, false detection of the unevenness can be suppressed.

[0021] The 2 floor surface state detection device according to the 1 invention further includes an output information selection unit that selects and outputs the distance information of each pixel including the unevenness detected by the state detection unit. Thereby, by selectively outputting the distance information corresponding only to the pixels including the unevenness on the floor surface among all the pixels of the imaging device, the amount of data to be output can be significantly reduced, and the output load can be reduced.

[0022] The 3 distance measuring device according to the Or in the second invention invention includes the floor surface state detection device according to the first IlluminationThe apparatus includes a device and a light-receiving unit that detects the amount of reflection of electromagnetic waves irradiated from the lighting device. As a result, since the floor surface state detection device described above is provided inside the distance measurement device including the lighting device and the light-receiving unit, a distance measurement device capable of accurately detecting the state of the floor surface can be obtained.

[0023] The 4 distance measurement device according to the invention of No. 3 further includes a storage unit that stores at least one of distance information, angle information corresponding to each pixel included in the distance image, the orthogonal coordinate system of the distance measurement device, the installation height, the rotation coordinates obtained by rotating around an axis by the three-dimensional coordinates converted from the distance information and the angle information, the threshold value used when detecting the object, and the coordinate value of the pixel that is the output target. As a result, by storing distance information, angle information, orthogonal coordinate system, installation height, rotation coordinates, threshold value, coordinate values of pixels that are output targets, etc. in the distance measurement device, it is possible to perform processing for significantly reducing the amount of data to be output using the stored various data.

[0024] The 5 distance measurement device according to the invention of No. 3 or the invention of No. 4 further includes an output unit that outputs the distance information corresponding to the pixel to an external device. As a result, for example, by outputting only the distance information corresponding to the pixel determined and selected to include the object from the output unit to the external device, the amount of data of the information including the distance information output from the distance measurement device can be significantly reduced.

[0025] The 6 output control method according to the invention of No. is an output control method for controlling the output of information included in a distance image including distance information to an object, and includes a distance information acquisition step and an output information selection step. An angle information acquisition step, a three-dimensional coordinate conversion step, a plane detection step, a height calculation step, a coordinate rotation calculation step, a concavity and convexity detection step, a threshold setting step, The distance information acquisition step irradiates the object with electromagnetic waves from the lighting device and based on the phase difference between the reflected wave of the electromagnetic wave and the electromagnetic waveObtain the distance information to the object. The state detection step detects the state of the floor surface on which the object is placed based on the distance information acquired by the distance information acquisition unit. The angle information acquisition step acquires angle information corresponding to each pixel included in the distance image. The three-dimensional coordinate conversion step converts the distance information acquired by the distance information acquisition unit into three-dimensional coordinates based on the angle information acquired by the angle information acquisition unit. The plane detection step detects the floor surface on which the object is placed. The height calculation step calculates the installation height of the distance measuring device based on the distance information on the floor surface detected by the plane detection unit and the three-dimensional coordinates converted by the three-dimensional coordinate conversion unit. The coordinate rotation calculation step calculates the rotation coordinates obtained by rotating the three-dimensional coordinates converted from the distance information and the angle information in the three-dimensional coordinate conversion unit around an axis. The concavity and convexity detection step compares the height-direction coordinates of the rotation coordinates calculated in the coordinate rotation calculation unit with the installation height calculated in the height calculation unit, and when detecting an object having a positive or negative dimension in the height direction, detects the object as concavity and convexity on the floor surface. The threshold setting step sets first, second, and third thresholds as predetermined thresholds used when detecting concavity and convexity in the concavity and convexity detection unit. Then, the height calculation step calculates the average value of the coordinate values in the optical axis direction of a plurality of coordinate values obtained again by rotating the orthogonal coordinate system of the distance measuring device around an axis by the angle formed by the perpendicular line of the floor surface detected in the plane detection step and the optical axis of the distance measuring device as the installation height, and the concavity and convexity detection step determines that there is an object on the floor surface when the dimension in the height direction from the floor surface is larger than the first threshold, determines that there is a hole in the floor surface when the dimension in the height direction from the floor surface is smaller than the second threshold, and determines that there is a slope on the floor surface when the change amount of the dimension in the height direction from the floor surface of adjacent pixels is larger than the third threshold.

[0026] Here, for example, using the distance information to the object obtained from a TOF (Time-of-Flight) sensor that measures the distance to the measurement object by receiving the reflected light of the light irradiated from an LED (Light emitting diode) as a light source toward the object, the state of the floor surface is detected. Here, the detected state of the floor surface includes, for example, recesses such as holes formed in the floor surface, protrusions such as obstacles placed on the floor surface, and the like.

[0027] This floor surface state detection method may be implemented, for example, within a distance measuring device such as a TOF sensor, or may be implemented outside the distance measuring device. The electromagnetic waves irradiated from the lighting device include, for example, light in a broad sense (ultraviolet light, visible light, infrared light), γ (gamma) rays with a wavelength shorter than light, X-rays, microwaves with a wavelength longer than light, radio waves for broadcasting (short waves, medium waves, long waves), ultrasonic waves, elastic waves, quantum waves, and the like.

[0028] Note that in the distance information acquisition step, the distance information may be calculated by detecting the reflection of electromagnetic waves, or the distance information may be acquired from, for example, a distance sensor provided as an external device. Thereby, for example, even when the distance measuring device is mounted on a transport device or the like that can travel on the floor surface, the state of the traveling floor surface can be detected, so that operations such as transportation can be carried out while avoiding unevenness such as holes and obstacles. As a result, the state of the floor surface can be accurately detected, and operations such as transportation can be efficiently carried out. In addition, since concavities and convexities such as holes and obstacles formed on the floor surface can be accurately detected, operations such as conveyance can be efficiently performed. Furthermore, for example, in a configuration where the distance measuring device includes, as a light receiving unit, a light receiving lens and an imaging element that detects the amount of electromagnetic waves received through the light receiving lens, since the angle with respect to the subject is determined for each pixel of the imaging element, angle information corresponding to each pixel can be obtained. Also, using the angle information corresponding to each pixel, the distance information can be converted into three-dimensional coordinates (X, Y, Z). Also, as a pre-step for actually detecting the unevenness formed on the floor surface, when detecting the presence or absence of an object by detecting the floor surface, the distance (height) from the floor surface to the distance measuring device can be used as a reference value. Also, when calculating the installation height of the distance measuring device from the position of the floor surface and detecting the unevenness of the floor surface, the distance (height) from the floor surface to the distance measuring device can be used as a reference value. Also, regarding the distance to the floor surface measured by the distance measuring device, by rotating the orthogonal coordinate system of the distance measuring device around the axis by the angle formed between the perpendicular to the floor surface and the optical axis of the distance measuring device, the coordinate value in the optical axis direction of the coordinate value obtained again can be calculated as the installation height of the distance measuring device. That is, for example, by rotating around the axis by the angle formed between the perpendicular to the floor surface and the optical axis of the distance measuring device so that the Z-axis corresponding to the optical axis of the distance measuring device faces the vertical direction, the installation height can be calculated so as to obtain the same distance information as when the distance measuring device irradiates light directly downward and receives the reflected light. Also, by obtaining the average value of the coordinate values (distances) from the plane recognized as the floor surface and calculating this average value as the installation height, for example, even when there are minute unevenness or the like on the floor surface, the installation height of the distance measuring device from the floor surface can be accurately calculated. Also, when actually detecting the state of the floor surface, by calculating the rotation coordinates obtained by rotating the three-dimensional coordinates converted from the distance information and the angle information around the axis in the three-dimensional coordinate conversion unit, the presence or absence of unevenness on the floor surface can be detected. That is, by using the calculated rotation coordinates, substantially, the distance in the height direction (such as the depth of a hole, the height of an obstacle, etc.) measured in a state of looking from directly above the unevenness can be measured. Also, by comparing the installation height to the floor surface and the height of the object (coordinate in the height direction), it is possible to easily detect whether there are unevenness on the floor surface according to whether there is a change in the dimension in the height direction with respect to the surface of the floor surface. Also, when detecting the state of the floor surface (such as unevenness), when comparing the installation height to the floor surface and the height of the unevenness (coordinates in the height direction), if the difference in height is greater than or less than a predetermined threshold value, the object can be detected as the unevenness of the floor surface, thereby suppressing the false detection of unevenness.

[0029] No. 7 The floor state detection program according to the invention of 7 is a floor state detection program for detecting the state of the floor on which an object is placed, and According to the sixth invention causes a computer to execute each step of the floor state detection method.

[0030] Here, for example, using the distance information to the object obtained from a TOF (Time-of-Flight) sensor that measures the distance to the measurement object by receiving the reflected light of the light irradiated from an LED (Light emitting diode) as a light source toward the object, the state of the floor is detected. Here, the detected state of the floor includes, for example, recesses such as holes formed in the floor, protrusions such as obstacles placed on the floor, and the like.

[0031] This floor state detection method may be implemented, for example, within a distance measuring device such as a TOF sensor, or may be implemented outside the distance measuring device. The electromagnetic waves irradiated from the lighting device include, for example, light in a broad sense (ultraviolet light, visible light, infrared light), γ (gamma) rays with a wavelength shorter than light, X-rays, microwaves with a wavelength longer than light, radio waves for broadcasting (short waves, medium waves, long waves), ultrasonic waves, elastic waves, quantum waves, and the like.

[0032] Note that in the distance information acquisition step, the distance information may be calculated by detecting the reflection of electromagnetic waves, or the distance information may be acquired from, for example, a distance sensor provided as an external device.

[0033] Thereby, The same effects as those achieved by the floor surface state detection method according to the above-described sixth invention For example, even when a distance measuring device is mounted on a conveying device or the like that can travel on a floor surface, since the state of the floor surface being traveled can be detected, operations such as conveyance can be performed while avoiding unevenness such as holes and obstacles. such as the effect that the state of the floor surface can be accurately detected and operations such as conveyance can be efficiently performed.

Advantages of the Invention

[0034] According to the floor surface state detection device according to the present invention, the state of the floor surface can be accurately detected.

Brief Description of the Drawings

[0035]

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Embodiments for Carrying Out the Invention

[0036] (Embodiment 1) The distance measurement device 20 provided with the control unit (floor surface detection device) 10 according to an embodiment of the present invention will be described as follows with reference to FIGS. 1 to 16. (1) Configuration of the distance measurement device 20 As shown in FIG. 1, the distance measurement device 20 according to the present embodiment receives the reflected light of the light L1 (an example of electromagnetic wave) irradiated from the lighting device 21 provided on the surface of the main body 20a toward the object 30 through the light receiving lens 22 in the imaging element 23, and obtains distance information calculated according to the flight time of the light from when the light L1 is irradiated until it is received.

[0037] And as shown in FIG. 2, the distance measurement device 20 includes a lighting device 21, a light receiving lens 22, an imaging element 23, a control unit (floor surface detection device) 10, a storage unit 25, and an output unit 26. The lighting device 21 has, for example, an LED and irradiates the object 30 with light having a desired wavelength. Note that the lighting device 21 is provided with a projection lens (not shown) that condenses the light irradiated from the LED and guides it in the direction of the object 30.

[0038] The light-receiving lens 22 is provided to receive the reflected light that is irradiated from the lighting device 21 to the object 30 and reflected by the object 30, and guide it to the imaging element 23. The imaging element 23 has a plurality of pixels, receives the reflected light received by the light-receiving lens 22 at each of the plurality of pixels, photoelectrically converts it into an electrical signal, and transmits the electrical signal to the control unit 10. Further, the electrical signal corresponding to the amount of received reflected light detected by the imaging element 23 is used by the control unit 10 to calculate the distance information at each pixel.

[0039] As shown in FIG. 2, the control unit 10 is connected to the lighting device 21, the imaging element 23, and the storage unit 25. Then, the control unit 10 reads the lighting control program stored in the storage unit 25 and controls the lighting device 21 that irradiates light to the object 30. More specifically, the control unit 10 controls the lighting device 21 so as to irradiate optimal light according to the properties of the object such as the distance, shape, and color to the object 30 to which light is irradiated. Further, the control unit 10 calculates the distance information to the object 30 for each pixel based on the electrical signal corresponding to each pixel received from the imaging element 23. Note that the principle of distance measurement to the object 30 by the distance measurement device 20 will be described in detail in the following section.

[0040] As shown in FIG. 2, the storage unit 25 is connected to the control unit 10, and stores data such as a control program for controlling the lighting device 21 and the imaging element 23, the amount of light of the reflected light detected by the imaging element 23, the light reception timing, and the distance information calculated based on the amount of light of the reflected light. Further, the storage unit 25 stores information such as distance information, angle information, rectangular coordinate system, installation height, rotation coordinates, threshold value, and coordinate values of pixels to be output, which will be described later. The output unit 26 outputs the distance information corresponding to the pixels selected by the output information selection unit 19 (see FIG. 3) described later to an external device. The distance information corresponding to each pixel output from the output unit 26 is limited to the information corresponding to a selected part of the pixels, rather than all the pixels. Therefore, the output load can be reduced, and the load of post-processing in the external device that is the output destination can also be reduced.

[0041] (2) Configuration of the control unit 10 As shown in FIG. 3, the control unit 10 includes a distance calculation unit (distance information acquisition unit) 11, an angle information acquisition unit 12, a three-dimensional coordinate conversion unit 13, a plane detection unit 14, a height calculation unit 15, a coordinate rotation calculation unit 16, a threshold setting unit 17, an object detection unit (state detection unit) 18, and an output information selection unit 19.

[0042] Based on the distance measurement principle of the TOF (Time of Flight) method described later, the distance calculation unit 11 calculates the distance information to the object 30 corresponding to each pixel of the grayscale image captured by the imaging element 23. For the plurality of pixels constituting the distance image generated in the imaging element 23 that receives the reflected light through the light receiving lens 22, since the incident angle of the reflected light with respect to the subject is determined, the angle information corresponding to each pixel is acquired by the angle information acquisition unit 12.

[0043] The three-dimensional coordinate conversion unit 13 converts the distance information acquired by the distance calculation unit 11 into three-dimensional coordinates (X, Y, Z) in the orthogonal coordinate format based on the angle information acquired by the angle information acquisition unit 12 (see FIG. 7). The plane detection unit 14 detects the floor surface FL by designating the pixel range for detecting the floor surface FL on which the object 30 is placed as a reference when measuring the distance to the object 30 (calibration process).

[0044] The height calculation unit 15 calculates the installation height h of the distance measuring device 20 from the floor surface FL based on the three-dimensional coordinates (X, Y, Z) converted by the three-dimensional coordinate conversion unit 13 for the distance information (height) on the floor surface FL detected by the plane detection unit 14. More specifically, the height calculation unit 15 rotates the orthogonal coordinate system (X, Y, Z) of the distance measuring device 20 around the axis by the angle θ formed by the perpendicular to the floor surface FL and the optical axis of the distance measuring device 20, and calculates the coordinate value Zr in the optical axis direction among the coordinate values (X, Yr, Zr) obtained again as the installation height h (see Fig. 6).

[0045] In this embodiment, the height calculation unit 15 calculates the average value of the coordinate values in the Z direction of a plurality of coordinate values (Xr, Yr, Zr) obtained again by rotating the orthogonal coordinate system (X, Y, Z) of the distance measuring device 20 around the axis as the installation height h. The coordinate rotation calculation unit 16 calculates a rotation coordinate (orthogonal coordinate rotation format) obtained by rotating the three-dimensional coordinates (orthogonal coordinate format) converted from the distance information and the angle information by the three-dimensional coordinate conversion unit 13 around the axis (see Fig. 6).

[0046] The threshold setting unit 17 sets a predetermined threshold used when the object detection unit 18 detects the object 30. Note that the threshold set by the threshold setting unit 17 may be appropriately set to different values according to the form, shape, size, etc. of the detected object 30. When the object detection unit 18 compares the coordinate z in the height direction of the rotation coordinate calculated by the coordinate rotation calculation unit 16 with the installation height h calculated by the height calculation unit 15 and detects an object having a dimension in the height direction, the object detection unit 18 detects this object as the object 30 placed on the floor surface FL.

[0047] The output information selection unit 19 selects and outputs only the distance information corresponding to the pixels including the object 30 among the plurality of pixels constituting the distance image including the object 30 detected based on the distance information calculated by the distance calculation unit 11 as the output target.

[0048] <Principle of distance measurement by the distance measuring device 20> The principle of distance measurement to an object by the distance measuring device 20 of this embodiment will be described as follows with reference to FIG. 4. That is, in this embodiment, the control unit 10 (distance calculation unit 11) of the distance measuring device 20 calculates the distance to the object 30 based on the phase difference Φ (see FIG. 4) between the light emission wave of the light irradiated from the lighting device 21 and the light reception wave of the light received by the imaging element 23. Here, the phase difference Φ is represented by the following relational expression (1). Φ = atan(y / x) ·····(1) (x = a2 - a0, y = a3 - a1, a0 to a3 are the amplitudes at the points where the light reception wave is sampled 4 times at 90-degree intervals)

[0049] And the conversion formula from the phase difference Φ to the distance D is represented by the following relational expression (2). D = (c / (2×f LED ))×(Φ / 2π) + D OFFSET ·····(2) (c is the speed of light (≈3×10 8 m / s), f LED is the frequency of the light emission wave of the LED, D OFFSET is the distance offset.) Thereby, by receiving the reflected light of the light irradiated from the lighting device 21 and comparing the phase difference, the distance calculation unit 11 can easily calculate the distance to the object 30 using the speed of light c.

[0050] <Process of selecting the output target> The method of selecting the output target by the control unit 10 of the distance measuring device 20 of this embodiment will be described as follows with reference to the drawings. That is, in this embodiment, as shown in FIG. 5, it is assumed that the distance measuring device 20 is attached to the upper end of the support column P1 with a height h installed on the floor surface FL at an obliquely downward mounting angle, and there is an object 30 placed on the floor surface FL.

[0051] In this case, in the distance measuring device 20, the distances to the objects (the target object 30, the floor surface FL, etc.) reflected in all the pixels of the imaging element 23 are calculated, and as distance information corresponding to each pixel, three-dimensional coordinates (X, Y, Z) with the distance measuring device 20 as the origin are stored. The distance measuring device 20 of the present embodiment performs the following output control process in order to selectively output only the distance information of the pixels corresponding to the position where the target object 30 is located among the distance information corresponding to these respective pixels.

[0052] First, as preparation in advance, the distance measuring device 20 performs calibration to calculate the installation height h from the floor surface FL. Specifically, as shown in FIG. 5, the distance measuring device 20 measures distances in the orthogonal coordinate system (X, Y, Z) on the floor surface FL and acquires the measured result (X, Y, Z) coordinate values for each pixel.

[0053] Next, the distance measuring device 20 performs plane detection on the acquired results within a specified pixel range and obtains the coefficients a, b, c, d of the equation aX + bY + cZ + d = 0 of the plane α. Note that plane detection and the derivation of a, b, c, d can be performed by utilizing existing technologies. For example, it can be obtained using the sample code of plane detection (Plane model segmentation) presented in the Point Cloud Library (see, for example, http: / / pointclouds.org / documentation / tutorials / planar_segmentation.html, etc.).

[0054] Next, the distance measuring device 20 obtains the angle θ formed by the perpendicular to the floor surface FL and the Z axis of the orthogonal coordinate system of the distance measuring device 20. Here, the angle θ formed by the plane α shown in FIG. 6 and the Z axis (z + t = 0) of the orthogonal coordinate system of the distance measuring device 20 is obtained by the following relational expression (1). θ = cos-1(|a×0 + b×0 + c×1|÷((a 2 + b 2 + c 2 )1 / 2×(0 2 + 0 2 + 12 ))) ·····(1) By measuring the distance again using a rectangular coordinate rotation system obtained by rotating the rectangular coordinate system by θ degrees around the X axis, the coordinate values of the measurement results (Xr, Yr, Zr) of the rectangular coordinate rotation system at each pixel can be obtained.

[0055] Next, the distance measuring device 20 calculates the average value of Zr within the plane range where the plane α is detected, and calculates this average value as the height h from the floor surface FL. Regarding the process of converting the measured distance values at each pixel of the imaging element 23 into three-dimensional coordinates based on the angle information, it is as follows when explained with reference to FIG. 7. That is, as shown in FIG. 7, the distance measuring device 20 converts the measured distance value r corresponding to each pixel into three-dimensional coordinates X, Y, Z using the angles θ and φ.

[0056] Note that r, θ, φ and X, Y, Z shown in FIG. 7 are defined as follows. X = r × sin θ cos φ Y = r × sin θ sin φ Z = r × cos θ (The measured value r is the magnitude of the distance vector r, the angle θ is the angle formed by the direction of the distance vector r and the Z axis, and the angle information φ is the angle formed by the projection vector of the distance vector r onto the X-Y plane and the X axis.) Next, regarding the process of converting the three-dimensional coordinates (X, Y, Z) obtained by converting the measured distance values corresponding to each pixel into a significant coordinate rotation system by rotating around the X axis, Y axis, and Z axis respectively, it will be explained with reference to FIG. 8.

[0057] Here, the distance measuring device 20 specifies the rotation angles around the X axis, Y axis, and Z axis, and calculates the rotated coordinate values Xr, Yr, Zr for the X, Y, Z coordinates of all pixels using the following relational expression (2).

[0058]

Equation

[0059] For example, as shown in FIG. 8, when the three-dimensional coordinate values of a certain pixel are (X, Y, Z) = (0, 1, 0), and there is no rotation around the X-axis and no rotation around the Y-axis and Z-axis, the coordinates after rotation (Xr, Yr, Zr) = (0, 0, 1). Subsequently, after obtaining the installation height h of the distance measuring device 20 by the calibration process as described above, as shown in FIG. 9, the distance to the actual object 30 is actually measured. That is, the distance is measured in the orthogonal coordinate rotation form rotated by θ degrees around the X-axis, and the measurement results (Xr, Yr, Zr) of the distance at each pixel of the imaging element 23 are obtained. At this time, in the distance measuring device 20, a predetermined threshold value S1 for detecting the object 30 is set by the threshold value setting unit 17.

[0060] Then, the distance measuring device 20 compares the value of Zr among the coordinates (Xr, Yr, Zr) obtained as the measurement result with the value of the installation height h calculated in the calibration process. If the magnitude of the difference exceeds a predetermined threshold value S1, it is determined that the object 30 is included in that pixel, and the coordinates (Xr, Yr, Zr) of the measurement result corresponding to that pixel are selected as the output target.

[0061] In the distance measuring device 20 of the present embodiment, for example, as shown in FIG. 9, an object 30 placed on the floor surface FL is detected, and the distance information to the object 30 is selected and output. At this time, the threshold value S1 is set as the threshold value for detecting the object 30 placed on the floor surface FL. Then, paying attention to Zr of the distance measurement result (Xr, Yr, Zr) obtained in the orthogonal coordinate rotation form, the calculation of the difference (h - Zr) is performed for each pixel of the imaging element 23.

[0062] Here, if the difference (h - Zr)>S1, it is determined that the object 30 is present at that pixel position, and the distance information corresponding to that pixel is selected and output. In the distance measurement device 20 of this embodiment, as described above, using the distance information and angle information to the object 30 acquired by the TOF method, the measured distance information is converted into the orthogonal coordinate rotation format. Then, the distance measurement device 20 compares the installation height h and the Zr value to distinguish the position where there is an object with a height difference from the floor surface FL of a predetermined threshold S1 or more and the position of only the floor surface without an object, and can detect the position where there is an object as a pixel where the object 30 exists.

[0063] Thereby, by selecting and outputting only the distance information corresponding to the pixel where the object 30 is detected, it is possible to avoid outputting unnecessary information such as the distance information to the position of the floor surface without the object 30, and the amount of data to be output can be significantly reduced. Next, the processing when the object detected using the distance information as described above is the hole 130a formed in the floor surface FL will be described with reference to FIG. 10.

[0064] Here, as shown in FIG. 10, the hole 130a formed in the floor surface FL is detected, and only the measurement result thereof is selected and output. Specifically, after obtaining the installation height h of the distance measurement device 20 by the above-described calibration process, as shown in FIG. 10, the distance to the actual object (hole 130a) is measured.

[0065] That is, the distance is measured in the orthogonal coordinate rotation format rotated by θ degrees around the X axis, and the measurement results (Xr, Yr, Zr) of the distances at the respective pixels of the imaging element 23 are acquired. At this time, in the distance measurement device 20, a predetermined threshold S2 for detecting the hole 130a is set by the threshold setting unit 17. Then, the distance measurement device 20 compares the value of Zr among the coordinates (Xr, Yr, Zr) of all the pixels acquired as the measurement results with the value of the installation height h calculated in the calibration process, and if the difference (h - Zr) is less than the predetermined threshold S2, it is determined that the hole 130a is included in that pixel, and the coordinates (Xr, Yr, Zr) of the measurement result corresponding to that pixel are selected as the output target.

[0066] Accordingly, as the state of the floor surface FL, it is possible to easily detect the position where the hole 130a is located, and by selecting and outputting only the distance information corresponding to the pixel where the hole 130a is detected, it is possible to avoid the output of unnecessary information such as the distance information to the position of the floor surface FL without the hole 130a, and the amount of data to be output can be significantly reduced. Next, the processing when the object detected using the distance information as described above is the slope 130b with a changing height formed on the floor surface FL will be described with reference to FIG. 11.

[0067] Here, as shown in FIG. 11, a slope 130b with a changing height is detected on the floor surface FL, and only the ranging result thereof is selected and output. Specifically, after obtaining the installation height h of the distance measuring device 20 by the calibration process described above, as shown in FIG. 11, the distance to the actual object (slope 130b) is actually measured.

[0068] That is, the distance is measured in the orthogonal coordinate rotation format rotated by θ degrees around the X axis, and the distance measurement results (Xr, Yr, Zr) at each pixel of the imaging element 23 are obtained. At this time, in the distance measuring device 20, a predetermined threshold value S3 for detecting the slope 130b is set by the threshold setting unit 17. Then, the distance measuring device 20 focuses on the value of Zr among the coordinates (Xr, Yr, Zr) of all the pixels obtained as the measurement results, and obtains the change amount (ΔZr / ΔXr)+(ΔZr / ΔYr) between the adjacent upper, lower, left, and right pixels.

[0069] And when (ΔZr / ΔXr)+(ΔZr / ΔYr) is larger than the predetermined threshold value S3, it is selected and output as the ranging result corresponding to the pixel where the slope 130b is detected. As a result, as the state of the floor surface FL, by selecting and outputting only the distance information corresponding to the pixels where the slope 130b is detected, it is possible to avoid outputting unnecessary information such as the distance information to the position of the floor surface FL without the slope 130b, and significantly reduce the amount of data to be output.

[0070] <Flow of processing of floor surface state detection method> With the above configuration, the distance measuring device 20 of the present embodiment implements a floor surface state detection method according to the flowcharts shown in FIGS. 12 to 16. That is, in FIG. 12, as described above, as a stage before measuring the distance to the actual object 30, a calibration process is performed.

[0071] In step S11, the distance calculation unit 11 of the distance measuring device 20 calculates distance information from the phase difference information at all pixels of the imaging element 23. Next, in step S12, based on the distance information for each pixel calculated in step S11 and the angle information corresponding to each pixel acquired by the angle information acquisition unit 12, the three-dimensional coordinate conversion unit 13 converts the distance information into three-dimensional coordinates (X, Y, Z) in orthogonal coordinate form.

[0072] Next, in step S13, the plane detection unit 14 performs a plane detection process on a predetermined plane range on the floor surface FL where the distance measuring device 20 is installed. Next, in step S14, the height calculation unit 15 calculates the angle θ (see FIG. 6) formed by the Z axis of the three-dimensional coordinates of the distance measuring device 20 and the perpendicular line to the floor surface FL. Next, in step S15, the coordinate rotation calculation unit 16 calculates coordinates (Xr, Yr, Zr) in orthogonal coordinate rotation form obtained by rotating the three-dimensional coordinates by the specified angle θ around the three axes at all pixels.

[0073] Next, in step S16, the height calculation unit 15 obtains the average value of Zr in a predetermined plane range of the floor surface FL and sets this as the installation height h. In the distance measurement device 20 of this embodiment, as a pre - step of measuring the distance to the actual object 30, calibration processing is performed to set the installation height h of the distance measurement device 20, which is used as a reference for detecting the position of the object 30, by the above - described processing.

[0074] Subsequently, in FIG. 13, after performing the calibration processing shown in FIG. 12, a step of measuring the distance to the actual object 30 is carried out. That is, in step S21, the distance calculation unit 11 calculates the distance information to the object corresponding to each of a plurality of pixels using the phase difference information acquired at all the pixels of the imaging device 23.

[0075] Next, in step S22, the three - dimensional coordinate conversion unit 13 converts the distance information calculated at all the pixels of the imaging device 23 into three - dimensional coordinates (X, Y, Z) in orthogonal coordinate form based on the angle information for each pixel acquired by the angle information acquisition unit 12. Next, in step S23, the coordinate rotation calculation unit 16 rotates the three - dimensional coordinates corresponding to all the pixels by a predetermined angle θ around the three axes of X, Y, and Z to calculate the rotated coordinates (Xr, Yr, Zr).

[0076] Next, in step S24, in order to check one by one whether each pixel of the imaging device 23 is a pixel having distance information to be output, for example, in order to start from the lower - left end of all the pixels of the imaging device 23, i = 0 and j = 0 are set. Next, in step S25, the Z - axis coordinate value Zr after rotation of the pixel (i, j) is compared with the installation height h, and the coordinates (Xr, Yr, Zr) are saved as selection targets for the pixels determined to have a difference greater than or equal to predetermined thresholds S1, S2, S3 set according to the object 30 to be detected.

[0077] Note that the content of the processing in step S25 varies depending on the type of the object 30, and thus the details of the processing will be described in detail later. Next, in step S26, set i = i + 1, and check whether the adjacent pixel is a pixel with distance information to be output. Next, in step S27, determine whether the condition i < Max_i is satisfied. That is, in step S27, check whether the pixels of the image sensor 23 have been verified from end to end in the horizontal direction.

[0078] Here, if it is determined that the verification has not yet been performed up to the end (MAX) in the horizontal direction, return to step S25, and verify whether the pixel has distance information to be output. On the other hand, if it is determined that the verification has been performed up to the end (MAX) in the horizontal direction, move to step S28. Next, in step S28, since it is determined in step S27 that the verification has been performed up to the pixel at the maximum position (end) in the horizontal direction, set i = 0 and j = j + 1 to move to the pixels in the row above.

[0079] Next, in step S29, determine whether the condition j < Max_j is satisfied. That is, in step S29, check whether the pixels of the image sensor 23 have been verified from end to end in the vertical direction. Here, if it is determined that the verification has not yet been performed up to the end (MAX) in the vertical direction, return to step S25, and verify whether the pixel has distance information to be output. On the other hand, if it is determined that the verification has been performed up to the end (MAX) in the vertical direction, move to step S30.

[0080] Next, in step S30, since the verification of all the pixels of the image sensor 23 is completed, based on the result of the verification in step S25, output the coordinates (Xr, Yr, Zr) corresponding to the selected pixel. Thereby, by selecting and outputting only the distance information corresponding to the pixels where the object 30 is detected, it is possible to avoid outputting the distance information for all the pixels corresponding to the position of the floor surface FL without the object 30, and significantly reduce the amount of data to be output.

[0081] <When the detection target is the object 30> Here, a process of verifying whether each pixel of the imaging element 23 in step S25 of FIG. 13 described above has distance information to be output will be described in detail with reference to FIG. 14, particularly the process when the object 30 is an object placed on the floor surface FL. That is, in step S31, the coordinate Zr value corresponding to the vertical direction in the orthogonal coordinate rotation system of the target pixel (i, j) is subtracted from the height h from the floor surface FL obtained by the calibration process shown in FIG. 12 to calculate (h - Zr).

[0082] Next, in step S32, it is determined whether the result (h - Zr) of the subtraction process in step S31 is greater than a predetermined threshold value S1 set by the threshold setting unit 17 in order to determine the presence or absence of the object 30 placed on the floor surface FL. Here, if it is determined that the result (h - Zr) of the subtraction process is greater than the threshold value S1, it is recognized that the object 30 included in the target pixel is an object having a height dimension from the floor surface FL equal to or greater than the threshold value, and the process proceeds to step S33.

[0083] On the other hand, if it is determined that the result (h - Zr) of the subtraction process is smaller than the threshold value S1, it is recognized that the object 30 included in the target pixel is an object having almost no height dimension from the floor surface FL or the floor surface FL, and the process proceeds to step S35. Next, in step S33, since it was recognized in step S32 that the object 30 included in the target pixel has a height dimension from the floor surface FL equal to or greater than the threshold value, the object detection unit 18 determines that there is an object 30 on the floor surface FL.

[0084] Next, in step S34, the output information selection unit 19 selects the coordinates (Xr, Yr, Zr) of the target pixel (i, j) determined to have the object 30 and its object ID (01) as the output targets. Next, in step S35, since it was recognized in step S32 that the object 30 included in the target pixel is an object having almost no height dimension from the floor surface FL or the floor surface FL, it is determined that there is no object at the position on the floor surface FL corresponding to that pixel, and the process proceeds to step S26. Thus, it is possible to easily determine whether or not a target object 30 placed on the floor surface FL is included in a target pixel by using a threshold value S1 set to determine the presence or absence of an object (target object 30) placed on the floor surface FL.

[0085] <When the detection target is the hole 130a> Here, a process of verifying whether or not each pixel of the imaging element 23 in step S25 of FIG. 13 described above has distance information to be an output target, particularly, a process in the case where the target object 30 is a hole 130a (see FIG. 10) formed in the floor surface FL will be described in detail with reference to FIG. 15.

[0086] That is, in step S41, a coordinate Zr value corresponding to the vertical direction in the orthogonal coordinate rotation system of the target pixel (i, j) is subtracted from the height h from the floor surface FL obtained by the calibration process shown in FIG. 12 to calculate (h - Zr). Next, in step S42, it is determined whether or not the result (h - Zr) of the subtraction process in step S41 is smaller than a predetermined threshold value S2 set by the threshold value setting unit 17 in order to determine the presence or absence of the hole 130a formed in the floor surface FL.

[0087] That is, when the target object is the hole 130a, the distance information of the corresponding pixel acquired by the distance measuring device 20 becomes larger than the installation height h to the floor surface FL. Therefore, here, based on the fact that the value of (h - Zr) becomes a negative value for the pixel corresponding to the hole 130a, it is determined whether or not it becomes smaller than the threshold value S2 set for determination. Here, when it is determined that the result (h - Zr) of the subtraction process is smaller than the threshold value S2, it is recognized that the target object 30 included in the target pixel is the hole 130a below the floor surface FL, and the process proceeds to step S43.

[0088] On the other hand, when it is determined that the result (h - Zr) of the subtraction process is larger than the threshold value S2, it is recognized that the target object 30 included in the target pixel is an object having almost no depth dimension from the floor surface FL or the floor surface FL, and the process proceeds to step S45. Next, in step S43, in step S42, since it is determined that the height dimension of the object 30 included in the target pixel from the floor surface FL is smaller than the threshold value S2, the object detection unit 18 determines that there is a hole 130a in the floor surface FL.

[0089] Next, in step S44, the output information selection unit 19 selects the coordinates (Xr, Yr, Zr) of the target pixel (i, j) determined to have the hole 130a and its object ID (02) as the output targets. Next, in step S45, in step S42, since the object included in the target pixel is recognized as an object with almost no depth dimension from the floor surface FL or the floor surface FL, it is determined that there is no hole 130a at the position on the floor surface FL corresponding to the pixel, and the process proceeds to step S26. Thereby, it is possible to easily determine whether or not the target pixel includes the hole 130a formed in the floor surface FL by using the threshold value S2 set for determining the presence or absence of the hole 130a formed in the floor surface FL.

[0090] <When the detection target is the slope 130b> Here, a process of verifying whether each pixel of the imaging element 23 in step S25 of FIG. 13 described above has distance information to be an output target, particularly, a process when the object 30 is the slope 130b (see FIG. 11) on the floor surface FL will be described in detail with reference to FIG. 16.

[0091] That is, in step S51, in order to determine the presence or absence of the slope 130b whose dimension in the height direction changes, the change amount ΔZr / ΔXr of Zr between a certain pixel position (i, j) and the pixel position (i-1, j) adjacent to it in the minus lateral direction is calculated. Further, the change amount ΔZr / ΔYr of Zr between a certain pixel position (i, j) and the pixel position (i, j-1) adjacent to it in the minus vertical direction is calculated.

[0092] Next, in step S52, it is determined whether the sum of ΔZr / ΔXr and ΔZr / ΔYr calculated in step S51 is greater than a predetermined threshold S3 set by the threshold setting unit 17 in order to determine the presence or absence of the slope 130b on the floor surface FL, that is, whether the conditional expression {(ΔZr / ΔXr)+(ΔZr / ΔYr)}>threshold S3 is satisfied. That is, when the object is the slope 130b, based on the fact that the change amounts in the height direction with respect to the pixels adjacent in the horizontal and vertical directions become equal to or greater than a predetermined value, it is determined whether the sum of the vertical and horizontal of the change amounts is greater than the threshold S3 set for determination.

[0093] Here, if the determination result is determined to be greater than the threshold S3, it is recognized that the object 30 included in the target pixel may be the slope 130b, and the process proceeds to step S53. On the other hand, if the determination result is determined to be smaller than the threshold S3, it is recognized that the slope 130b is not included in the target pixel, and the process proceeds to step S57. Next, in step S53, the change amount ΔZr / ΔXr of Zr between a certain pixel position (i,j) and the pixel position (i+1,j) adjacent to it on the plus side in the horizontal direction is calculated. Further, the change amount ΔZr / ΔYr of Zr between a certain pixel position (i,j) and the pixel position (i,j+1) adjacent to it on the plus side in the vertical direction is calculated.

[0094] Next, in step S54, it is determined whether the sum of ΔZr / ΔXr and ΔZr / ΔYr calculated in step S53 is greater than the threshold S3, that is, whether the conditional expression {(ΔZr / ΔXr)+(ΔZr / ΔYr)}>S3 is satisfied. Here, if the determination result is determined to be greater than the threshold S3, it is recognized that the object 30 included in the target pixel is the slope 130b, and the process proceeds to step S55.

[0095] On the other hand, if the determination result is determined to be smaller than the threshold S3, it is recognized that the slope 130b is not included in the target pixel, and the process proceeds to step S57. Next, in step S55, since in step S54 it is determined that the sum of ΔZr / ΔXr and ΔZr / ΔYr is greater than the threshold value S3, the object detection unit 18 determines that there is a slope 130b on the floor surface FL.

[0096] Next, in step S56, the output information selection unit 19 selects, as output targets, the coordinates (Xr, Yr, Zr) of the target pixel (i, j) for which it is determined that there is a slope 130b and its object ID (03). Next, in step S57, since in step S54 it is determined that the sum of ΔZr / ΔXr and ΔZr / ΔYr is less than the threshold value S3, it is recognized that there is almost no change in the dimension of the object in the height direction between adjacent pixels. Therefore, it is determined that there is no slope on the floor surface and the process proceeds to step S26. Thereby, it is possible to easily determine whether or not the target pixel includes the slope 130b placed on the floor surface FL by using the threshold value S3 set for determining the presence or absence of the slope 130b on the floor surface FL.

[0097] <Detection process of the state of the floor surface FL> As described above, the distance measuring device 20 of the present embodiment can select and output only the distance information of the target pixel including the object by determining whether or not all the pixels included in the imaging element 23 include an object (object, hole, slope, etc.) by using the distance information.

[0098] Also, the distance measuring device 20 of the present embodiment can further detect the state of the floor surface FL by continuously executing the flowcharts of FIGS. 14 to 16. Specifically, regarding the process of step S25 in FIG. 13, by continuously executing the flowcharts shown in FIGS. 14 to 16, it is possible to detect the presence or absence of an object, the presence or absence of a hole, the presence or absence of a slope, etc. as the state of the floor surface FL by using three threshold values S1, S2, and S3.

[0099] Therefore, first, determination processing is performed using the threshold value S1 according to the flowchart shown in FIG. 14. If an object having a height dimension is detected on the floor surface FL, it is determined that there is an object 30 placed on the floor surface FL. If no object is detected, determination processing is performed according to the flowchart shown in FIG. 15. Then, determination processing is performed using the threshold value S2 according to the flowchart shown in FIG. 15. If a hole 130a having a depth dimension is detected on the floor surface FL, it is determined that there is a hole 130a formed on the floor surface FL. If no hole 130a is detected, determination processing is performed according to the flowchart shown in FIG. 16.

[0100] Finally, determination processing is performed using the threshold value S3 according to the flowchart shown in FIG. 16. If a slope 130b is detected on the floor surface FL, it is determined that there is a slope 130b on the floor surface FL. If no slope 130b is detected, the state detection process of the floor surface FL is terminated, and the process proceeds to step S26. As a result, by performing determination processing using different threshold values S1, S2, and S3, for example, even when the distance measuring device 20 is mounted on a transport device capable of traveling on the floor surface FL, the presence or absence of unevenness such as the hole 130a on the floor surface FL and the presence or absence of obstacles can be accurately determined, and the transport operation can be smoothly performed.

[0101] [Other Embodiments] As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention. (A) In the above embodiment, an example in which the present invention is realized as a floor surface state detection device and a floor surface state detection method has been described. However, the present invention is not limited to this.

[0102] For example, the present invention may be realized as a floor surface state detection program that causes a computer to execute the floor surface state detection method of the above-described floor surface state detection device. This floor surface state detection program is stored in a memory (storage unit) mounted on the floor surface state detection device, and the CPU reads the floor surface state detection program stored in the memory and causes the hardware to execute each step. More specifically, by the CPU reading the program and executing the above-described distance information acquisition step and state detection step, the same effects as described above can be obtained. Further, the present invention may also be realized as a recording medium storing the floor surface state detection program of the floor surface state detection device.

[0103] (B) In the above embodiment, as the distance information acquisition unit, the distance calculation unit 11 that calculates the distance information corresponding to each pixel of the distance image by the TOF method has been described as an example. However, the present invention is not limited thereto.

[0104] For example, a configuration may be adopted in which the distance information corresponding to each pixel of the distance image obtained by the TOF method is acquired from an external distance measuring device. That is, the output control device of the present invention may be provided separately from the distance measuring device, and may be configured to acquire distance information from the distance measuring device, select and output the distance information corresponding to the pixel to be output.

[0105] (C) In the above embodiment, an example in which the mounting angle θ of the distance measuring device 20 is calculated by arithmetic operation has been described. However, the present invention is not limited thereto. For example, when the mounting angle of the distance measuring device is known in advance, a configuration may be adopted in which the installation height or the like is obtained using the mounting angle θ.

[0106] (D) In the above embodiment, an example in which the reflected light of the light irradiated from the lighting device 21 to the object is detected to measure the distance to the object has been described. However, the present invention is not limited thereto. For example, in addition to light in the broad sense (ultraviolet light, visible light, infrared light) from a lighting device to an object, electromagnetic waves such as γ (gamma) rays, X-rays with wavelengths shorter than light, microwaves with wavelengths longer than light, and radio waves for broadcasting (short waves, medium waves, long waves) may be irradiated, and the distance to the object may be measured by detecting the reflection thereof. That is, the light irradiated to the object may be other electromagnetic waves having the property that the reflection amount thereof attenuates in inverse proportion to the square of the distance.

[0107] (E) In the above embodiment, as the objects detected using the distance information, an object placed on the floor surface FL, the hole 130a, and the slope 130b have been described as examples. However, the present invention is not limited thereto.

[0108] For example, the detectable object may be an object other than the above. In this case, by using the threshold values set according to the form, size, shape, etc. of each object, the presence or absence of each object can be detected.

Industrial Applicability

[0109] Since the distance measuring device of the present invention has the effect of being able to reduce the data amount of the information including the output distance information, it is widely applicable to distance measuring devices such as TOF sensors, for example.

Explanation of Signs

[0110] 10 Control unit (floor detection device) 11 Distance calculation unit (distance information acquisition unit) 12 Angle information acquisition unit 13 Three-dimensional coordinate conversion unit 14 Plane detection unit 15 Height calculation unit 16 Coordinate rotation calculation unit 17 Threshold setting unit 18 Object detection unit (state detection unit) 19 Output information selection unit 20 Distance measuring device 20a Body part 21 Lighting device 22 Light-receiving lens 23 Image sensor 25 Memory unit 26 Output unit 30 Object 130a Hole 130b Slope D Distance FL Floor surface L1 Light P1 Support pillar

Claims

1. A floor state detection device that detects the state of the floor surface on which an object is placed, comprising: a distance information acquisition unit that acquires distance information to the object based on a phase difference between an electromagnetic wave irradiated from an illumination device to the object and a reflected wave of the electromagnetic wave; a state detection unit that detects the state of the floor surface on which the object is placed based on the distance information acquired by the distance information acquisition unit; an angle information acquisition unit that acquires angle information corresponding to each pixel included in a distance image; a three-dimensional coordinate conversion unit that converts the distance information acquired by the distance information acquisition unit into three-dimensional coordinates based on the angle information acquired by the angle information acquisition unit; a plane detection unit that detects the floor surface on which the object is placed; a height calculation unit that calculates the installation height of the distance measuring device based on the distance information on the floor surface detected by the plane detection unit and based on the three-dimensional coordinates converted by the three-dimensional coordinate conversion unit; a coordinate rotation calculation unit that calculates a rotated coordinate obtained by rotating the three-dimensional coordinates converted from the distance information and the angle information by the three-dimensional coordinate conversion unit around an axis; an unevenness detection unit that compares the coordinate in the height direction of the rotated coordinate calculated by the coordinate rotation calculation unit with the installation height calculated by the height calculation unit, and when detecting an object having a positive or negative dimension in the height direction, detects the object as an unevenness on the floor surface; a threshold setting unit that sets first, second, and third thresholds as predetermined thresholds used when detecting the unevenness by the unevenness detection unit; and comprising: the height calculation unit calculates, as the installation height, an average value of coordinate values in the optical axis direction of a plurality of coordinate values obtained by rotating the orthogonal coordinate system of the distance measuring device around an axis by an angle formed by a perpendicular to the floor surface detected by the plane detection unit and the optical axis of the distance measuring device; when the dimension in the height direction from the floor surface is greater than the first threshold, the unevenness detection unit determines that there is an object on the floor surface, when the dimension in the height direction from the floor surface is less than the second threshold, the unevenness detection unit determines that there is a hole in the floor surface, and when a change amount of the dimension in the height direction from the floor surface of an adjacent pixel is greater than the third threshold, the unevenness detection unit determines that there is a slope on the floor surface Floor state detection device.

2. further comprising an output information selection unit that selects and outputs the distance information of each pixel including the unevenness detected by the state detection unit. The floor surface state detection device according to claim 1.

3. The floor surface state detection device according to claim 1 or 2, An illumination device that irradiates the object with electromagnetic waves, A light receiving unit that detects the amount of reflection of the electromagnetic waves irradiated from the illumination device, A distance measuring device provided with.

4. The distance information, the angle information corresponding to each pixel included in the distance image, the orthogonal coordinate system of the distance measuring device, the installation height, the rotation coordinates obtained by rotating the three-dimensional coordinates converted from the distance information and the angle information around an axis, the threshold value used when detecting the object, and a storage unit that stores at least one of the coordinate values of the pixels to be output, further provided. The distance measuring device according to claim 3.

5. It further includes an output unit that outputs the distance information corresponding to the pixel to an external device. The distance measuring device according to claim 3 or 4.

6. A floor surface state detection method for detecting the state of the floor surface on which an object is placed, A distance information acquisition step of acquiring distance information to the object based on the phase difference between the electromagnetic waves irradiated from the illumination device to the object and the reflected waves of the electromagnetic waves, A state detection step of detecting the state of the floor surface on which the object is placed based on the distance information acquired in the distance information acquisition step, An angle information acquisition step of acquiring angle information corresponding to each pixel included in the distance image, A three-dimensional coordinate conversion step of converting the distance information acquired in the distance information acquisition step into three-dimensional coordinates based on the angle information acquired in the angle information acquisition step, A plane detection step of detecting the floor surface on which the object is placed, A height calculation step of calculating the installation height of the distance measuring device based on the distance information on the floor surface detected in the plane detection step and the three-dimensional coordinates converted in the three-dimensional coordinate conversion step, A coordinate rotation calculation step of calculating rotation coordinates obtained by rotating the three-dimensional coordinates converted from the distance information and the angle information in the three-dimensional coordinate conversion step around an axis, When an object having a positive or negative dimension in the height direction is detected by comparing the coordinate in the height direction of the rotation coordinates calculated in the coordinate rotation calculation step with the installation height calculated in the height calculation step, an unevenness detection step of detecting the object as an unevenness on the floor surface. A threshold setting step of setting first, second, and third threshold values as a predetermined threshold value used when detecting the unevenness in the unevenness detection step; comprising The height calculation step calculates, as the installation height, an average value of coordinate values in the optical axis direction of a plurality of coordinate values obtained again by rotating the orthogonal coordinate system of the distance measuring device around the axis by an angle formed by a perpendicular line of the floor surface detected in the plane detection step and the optical axis of the distance measuring device. In the unevenness detection step, when the dimension in the height direction from the floor surface is larger than the first threshold value, it is determined that the object is on the floor surface. When the dimension in the height direction from the floor surface is smaller than the second threshold value, it is determined that there is a hole in the floor surface. When the amount of change in the dimension in the height direction from the floor surface of the adjacent pixel is larger than the third threshold value, it is determined that there is a slope on the floor surface. Floor surface state detection method. **Claim 7** A floor surface state detection program for detecting the state of a floor surface on which an object is placed, A floor surface state detection program that causes a computer to execute each step of the floor surface state detection method according to claim 6.

Images