JP5482032B2 - Distance measuring device and distance measuring method - Google Patents

Description

  The present invention relates to a distance measuring device and a distance measuring method.

  Conventionally, a technique for measuring a distance to a measurement target is known. In such a technique, a non-periodic projection pattern is generated using a random number, and this is irradiated onto a measurement target by a projector, and the measurement target irradiated with the projection pattern is set to a reference camera at a different position. And the reference camera and the reference camera and the reference camera are associated with the irradiated light, and the distance to the measurement object is measured using the parallax of each pixel of the associated reference camera and reference camera. The technique to do is known (refer patent document 1).

JP 2001-91232 A

  However, in the prior art, since the two cameras, the standard camera and the reference camera, are used for imaging, there is a difference in the direction of the measurement target viewed from these two cameras and the distance to the measurement target. It will end up. In the prior art, due to such a difference, the projection pattern irradiated to the measurement object has a distortion and a difference in size, and as a result, irradiation of images captured by the reference camera and the reference camera is performed. There is a problem in that an error occurs in the light association, which causes a decrease in distance measurement accuracy.

  The problem to be solved by the present invention is to provide a distance measuring device and a distance measuring method capable of appropriately measuring a distance to a measurement target.

The present invention irradiates light with a light projection pattern composed of a plurality of light projection dots on the measurement target, and measures the distance to the measurement target by imaging the measurement target irradiated with the light. A plurality of light projection dots constituting the light projection pattern are grid lines which are a plurality of lines parallel to a straight line connecting an irradiation position of the light and an imaging position on a plane perpendicular to the optical axis of the light. Each of the plurality of light projection dots is different from each other in the combination of the light projection grid lines each having a predetermined pair of grid lines as both ends and demarcating the both ends. , Based on the position of the grid line defining both ends of the projection dot and the position of the imaging dot on the imaging screen, the imaging dot and the projection dot are associated with each other. Based on the projected dot There by measuring the distance to the measurement target, solving the above problems.

  According to the present invention, each of the plurality of projection dots forming the projection pattern has a predetermined pair of grid lines as both ends. Therefore, the correspondence between the projection dot and the corresponding imaging dot As a result, it is possible to appropriately measure the distance to the measurement target.

FIG. 1 is a block diagram illustrating a configuration of a vehicle 1 according to the present embodiment. FIG. 2 is a diagram for explaining the distance measuring method according to the present embodiment. FIG. 3 is a diagram for explaining the distance measuring method according to the present embodiment. FIG. 4 is a diagram for explaining the distance measuring method according to the present embodiment. FIG. 5 is a diagram for explaining the distance measuring method according to the present embodiment. FIG. 6 is a diagram illustrating an example of a light projection pattern according to the present embodiment. FIG. 7 is a diagram for explaining a reading processing order of signals accumulated in the imaging pixels arranged on the imaging element provided in the imaging device 30. FIG. 8 is a diagram for explaining the relationship between the installation positions of the projector 20 and the imaging device 30. FIG. 9 is a diagram for explaining the relationship between the installation positions of the projector 20 and the imaging device 30. FIG. 10 is a flowchart showing distance measurement processing according to the present embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration of a vehicle 1 according to the present embodiment. As shown in FIG. 1, the vehicle 1 according to the present embodiment includes a controller 10, a projector 20, and an imaging device 30. Each of these components is connected by an in-vehicle LAN such as a CAN (Controller Area Network) and can exchange information with each other.

  The light projector 20 irradiates the measurement object existing in front of the vehicle 1 with light with a predetermined light projection pattern toward the front of the vehicle 1. As will be described later, the projector 20 includes at least a light source and a light projection pattern slide 21 disposed in front of the light source (see FIG. 2).

  The imaging device 30 includes an imaging device in which a plurality of imaging pixels are arranged, takes a luminance image with the imaging device, and converts this to image data. As such an imaging device 30, for example, a device having a CCD (Charge Coupled Devices), a CMOS (Complementary Metal Oxide Semiconductor), or the like as an imaging device can be cited.

  The projector 20 and the imaging device 30 may be installed so that light can be emitted in front of the vehicle 1 or so that the front of the vehicle 1 can be imaged. The installation position is arbitrary, but for the reason described later. It is desirable that the arrangement direction of the imaging pixels constituting the imaging device provided in the imaging device 30 is set in a direction parallel to the straight line connecting the projector 20 and the imaging device 30.

  The controller 10 controls the projector 20 and the imaging device 30 to execute processing for measuring the distance to the measurement object existing in front of the vehicle 1. The controller 10 is accessible to a ROM (Read Only Memory) storing a program for executing the distance measurement processing according to the present embodiment and a CPU (Central Processing Unit) executing the program stored in the ROM. RAM (Random Access Memory) functioning as a storage device.

  Here, before describing specific processing executed by the controller 10, a distance measuring method according to the present embodiment will be described. FIG. 2 is a diagram for explaining the distance measuring method according to the present embodiment.

  FIG. 2 shows a scene in which light from the light source of the projector 20 is applied to the measurement object 100a via the projection pattern slide 21 provided in the projector 20. The light projection pattern slide 21 transmits a part of the light from the light source of the light projector 20 and blocks a part thereof in order to set a pattern of light emitted from the light projector 20 (light projection pattern). And arranged so as to be perpendicular to the optical axis of the light from the light source of the projector 20. In addition, the light projection pattern set by the light projection pattern slide 21 includes a portion that transmits light on the light projection pattern slide 21 and a portion that blocks light. In this embodiment, the portion that transmits light. Is “projection dot”.

  And in FIG. 2, a specific light projection dot is shown with the code | symbol "22a" among the some light projection dots which comprise a light projection pattern, and the irradiation light based on this light projection dot 22a is set to the measurement object 100a. It shows the irradiated scene. As shown in FIG. 2, the irradiation light based on the projection dot 22a is irradiated to the measurement object 100a, and the reflective dot 101a is produced on the measurement object 100a.

  On the other hand, in this embodiment, the imaging object 30 images the measurement object 100a on which the irradiation light based on the projection dots 22a is projected. As shown in FIG. 2, an image based on the reflective dots 101 a generated on the measurement object 100 a is picked up as indicated by reference numeral “102 a” in FIG. 2 on the imaging screen 31 of the imaging device 30. It will be. In the present embodiment, an image based on such a reflective dot imaged on the imaging screen 31 of the imaging device 30 is referred to as an “imaging dot”.

  In the scene shown in FIG. 2, the position of the projection dot 22 a on the projection pattern slide 21 of the projector 20 (that is, the irradiation direction of the irradiation light based on the projection dot 22 a) and the imaging screen 31 of the imaging device 30. The object to be measured from the vehicle 1 by performing distance measurement by triangulation from the position of the imaging dot 102a in the image (that is, the imaging direction on the imaging device 30) and the geometric positional relationship between the projector 20 and the imaging device 30. The distance to the object 100a can be measured.

  In FIG. 2, for the sake of simplicity, only a single projection dot 22a and an imaging dot 102a based thereon are shown. Therefore, in the scene shown in FIG. It can be clearly understood that it corresponds to the projection dot 22a. However, unlike the case of FIG. 2 which is a simplified example, the light projection pattern of the light irradiated by the light projector 22 of the present embodiment includes a plurality of light projection dots and corresponds to this. Since there are a plurality of reflection dots and imaging dots, it is necessary to associate them. Hereinafter, a method of associating the projection dots with the corresponding reflection dots and imaging dots in the present embodiment will be described.

  FIG. 3 is a diagram for explaining the distance measurement method according to the present embodiment. In FIG. 3, a plurality of measurement objects 100a and 100a ′ having different distances from the projector 20 (projection pattern slide 21) are shown. , 100a ″, shows the scenes irradiated with the irradiation light based on the projection dots 22a.

  As shown in FIG. 3, when the measurement object 100a is irradiated with the irradiation light based on the projection dot 22a, the reflection dot 101a is generated on the measurement object 100a as in the case of FIG. This is detected as the imaging dot 102 a on the imaging screen 31 of the imaging device 30.

  Similarly, when the measurement object 100a ′ is irradiated with the irradiation light based on the projection dot 22a, the reflection dot 101a ′ is generated on the measurement object 100a ′, and this is reflected on the imaging screen 31 of the imaging device 30. Will be detected as the imaging dot 102a '. Further, when the measurement object 100 a ″ is irradiated with the irradiation light based on the projection dot 22 a, the reflection dot 101 a ″ is generated on the measurement object 100 a ″, which is the imaging screen 31 of the imaging device 30. In the above, it is detected as an imaging dot 102a ''.

  In this way, as shown in FIG. 3, the reflection dots 101a, 101a ′, and 101a ″ of the measurement objects 100a, 100a ′, and 100a ″ having different distances from the projector 20 (projection pattern slide 21), respectively. The imaging dots 102a, 102a ′, 102a ″ corresponding to are detected at different positions on the imaging screen 31 of the imaging device 30. However, on the other hand, as is apparent from FIG. 3, the imaging dots 102a, 102a ′, 102a ″ corresponding to the reflective dots 101a, 101a ′, 101a ″ of these measurement objects 100a, 100a ′, 100a ″. Are arranged on one straight line A. In other words, the imaging dots 102a, 102a ', 102a "based on the irradiation light based on the single projection dot 22a have a property that they are arranged on the same straight line.

  As shown in FIG. 4, this is because the angle of the measurement object with respect to the light projection pattern slide 21 of the projector 20 is different, and as a result, the reflective dots generated on the measurement objects 100b, 100b ′, 100b ″. Even when the sizes of 101b, 101b ′, and 101b ″ change, the same tendency is observed.

  In addition, as shown in FIG. 4, even when the size of the reflective dots 101b, 101b ′, 101b ″ generated on the measurement objects 100b, 100b ′, 100b ″ is changed, the image on the imaging screen 31 of the imaging device 30 is changed. The upper end position and the lower end position of the imaging dots 102b, 102b ′, 102b ″ detected at the same time are located on the same straight line. That is, the upper end positions of the imaging dots 102b, 102b ′, 102b ″ on the imaging screen 31 are all located on the straight line indicated by the reference numeral “33b” in FIG. Both are located on a straight line indicated by reference numeral “33c”. The upper end position and the lower end position of the imaging dots 102b, 102b ′, 102b ″ are the upper end position of the light projection dot 22b on the light projection pattern slide 21 (that is, the position on the straight line indicated by the symbol “23b”) and the lower end. It corresponds to the position (that is, the position on the straight line indicated by reference numeral “23c”). That is, the projected dots on the projected pattern slide 21 and the imaging dots based on the projected dots have a relationship such that the upper end position and the lower end position thereof correspond to each other.

  Therefore, in the present embodiment, by utilizing such a property, a plurality of lines parallel to a straight line connecting the projector 20 and the imaging device 30 are arranged on the projection pattern slide 21 with the projection grid lines 23a, 23b, On the other hand, on the imaging screen 31, a plurality of lines parallel to the straight line connecting the projector 20 and the imaging device 30 are set as imaging grid lines 33a, 33b, 33c, and 33d. These are used to associate the projection dots with the imaging dots.

  That is, in the scene shown in FIG. 4, taking the imaging dot 102b as an example, the imaging dot 102b has its upper end defined by the imaging grid line 33b and its lower end position defined by the imaging grid line 33c. Therefore, in this embodiment, the light projection dots 23b and 23c corresponding to the imaging grid lines 33b and 33c are extracted, and the light projection dots are used as the light projection dots having the light projection grid lines 23b and 23c as upper and lower end positions. 22b can be detected, so that the imaging dot 102b and the projection dot 22b can be associated with each other. In FIG. 4, imaging grid lines 33a, 33b, 33c, and 33d correspond to the light projecting grid lines 23a, 23b, 23c, and 23d, respectively (the same applies to FIG. 5 described later). In FIG. 4, an example in which each of the imaging grid lines and the projection grid lines is four is shown, but the number of the grid lines is not particularly limited and can be set as appropriate.

  Further, for example, in the scene shown in FIG. 5, the imaging dot 102c corresponding to the reflective dot 101c generated on the measurement object 100c is defined at the upper end by the imaging grid line 33a, and the lower end position is the imaging grid line. 33b. The projection dots corresponding to the imaging grid lines 33a and 33b and having the projection grid lines 23a and 23b at the upper and lower end positions are the projection dots 22c. Thus, the projection dots 22c become the imaging dots 102c. It will be detected as a corresponding projection dot.

  Similarly, in the scene shown in FIG. 5, the imaging dot 102d corresponding to the reflective dot 101d generated on the measurement object 100d is delimited by the imaging grid line 33a at the upper end, and the lower end position by the imaging grid line 33c. It is defined. The projection dots corresponding to the imaging grid lines 33a and 33c and having the projection grid lines 23a and 23c at the upper and lower end positions are the projection dots 22d. Accordingly, the projection dots 22d become the imaging dots 102d. It will be detected as a corresponding projection dot.

  As described above, in the present embodiment, the imaging dots and the projection dots are associated with each other.

  The position of the associated projection dot 22c on the projection pattern slide 21 (that is, the irradiation direction of the irradiation light based on the projection dot 22c) and the position of the imaging dot 32c on the imaging screen 31 (that is, the imaging device). The distance from the vehicle 1 to the measurement object 100c can be measured by performing distance measurement by triangulation from the image pickup direction on 30) and the geometric positional relationship between the projector 20 and the image pickup device 30. . Similarly, from the position of the corresponding projection dot 22d on the projection pattern slide 21, the position of the imaging dot 32d on the imaging screen 31, and the geometrical positional relationship between the projector 20 and the imaging device 30, a triangle is obtained. By measuring the distance by surveying, the distance from the vehicle 1 to the measurement object 100d can be measured.

  As described above, in this embodiment, the distance to the measurement object is measured.

Returning to FIG. 1, the controller 10 provided in the vehicle 1 has various functions described below in order to execute the association process and the distance measurement process described above.
That is, the controller 10 has a light projection pattern generation function for generating a projection pattern of irradiation light by the projector 20, a projector control function for controlling the projection of irradiation light to the projector 20, and a captured image captured by the imaging device 20. Extraction function for extracting an image based on the reflection dot generated on the measurement object as an imaging dot, and an association function for associating the extracted dot extracted by the extraction function with the projection dot constituting the projection pattern And a distance measurement function for measuring the distance to the measurement object based on the associated projection dots and extraction dots.

  The light projection pattern generation function of the controller 10 is a function for generating a light projection pattern for controlling the light projection pattern slide 21 provided in the light projector 20. FIG. 6 shows an example of the light projection pattern set by the light projection pattern generation function. In FIG. 6, there are 14 light projection grid lines, and each light projection dot constituting the light projection pattern has different combinations of the light projection grid lines as the upper end and the lower end. That is, in the example shown in FIG. 6, when generating the light projection pattern, the upper end position and the lower end position are set so that there is no light projection dot. As described above, each projection dot constituting the projection pattern has a different combination of projection grid lines having an upper end and a lower end, so that each projection dot and the imaging screen 31 of the imaging device 30 are displayed. The imaging dots detected in step 1 can be made to correspond to each other with high accuracy.

Therefore, A _1, A 2 from the top fourteen projection grid _lines, and · · · A _14, the projection grid lines defining the upper end of each projection dots and A _n, projection grid defining a lower end line a when the a _m, the light projecting dots and thus identified by _{(a n,} a _m). In other words, there is nothing that has the same (A _n , A _m ).

  The projector control function of the controller 10 is a function for determining the projection illuminance of the projector 20 and controlling the projection operation of the projector 20.

  The extraction function of the controller 10 is a function for extracting, from the captured image captured by the imaging device 30, an image based on the reflection dots generated on the measurement target of the irradiation light irradiated from the projector 20, as the imaging dots. is there.

  The association function of the controller 10 is a function for associating the imaging dots extracted by the extraction function with the projection dots constituting the projection pattern of the projector 20. Specifically, the association function detects the imaging grid lines at the upper and lower ends of the imaging dots, detects the projection dots corresponding to the imaging grid lines, and performs the association.

For example, when the imaging screen 31 of the imaging device 30 has 14 imaging grid lines as in the example shown in FIG. 6, the 14 imaging grid lines are assigned to B ₁ , B ₂ ,. When B ₁₄ is set, B _x is an imaging grid line that defines the upper end of the imaging dot, and B _y is an imaging grid line that defines the lower end, the imaging dot is represented as (B _x , B _y ). It will be. Then, the associating function assumes that each of the projected dots represented by (A _n , A _m ) is a projected dot corresponding to x = n and y = m, and associates these correlated dots. Do.

  The distance measurement function of the controller 10 is a function for measuring the distance to the measurement object based on the projected light dots and the extracted dots that are associated by the association function. Specifically, the distance measurement function is configured such that the position of the associated projection dot on the projection pattern slide 21 (that is, the irradiation direction of the irradiation light based on the projection dot) and the position of the imaging dot on the imaging screen 31. The distance from the vehicle 1 to the measurement object is measured by performing distance measurement by triangulation from the geometrical positional relationship between the projector 20 and the imaging device 30 (that is, the imaging direction on the imaging device 30). To do.

  The distance measurement function calculates an angle with respect to the imaging grid line for each imaging dot detected on the imaging screen 31. Specifically, the distance measurement function calculates the angle between the imaging grid line that defines the upper and lower ends of the imaging dot, the line connecting the contact points with the imaging dot, and the imaging grid line, and calculates this angle. Is the angle to. By calculating the angle with respect to the imaging grid line for each imaging dot, it is possible to detect the inclination of the measurement object corresponding to each imaging dot with respect to the imaging grid line.

  As described above, the controller 10 includes the above-described functions in order to execute the distance measurement process according to the present embodiment.

  Next, the relationship between the installation positions of the projector 20 and the imaging device 30 will be described. FIG. 7 is a diagram for explaining a reading processing order of signals accumulated in the imaging pixels arranged on the imaging element provided in the imaging device 30. As shown in FIG. 7, the signals accumulated in the pixels arranged on the image sensor provided in the imaging device 30 are indicated by the arrows shown in FIG. 7 in order from the position indicated by (1) in FIG. Reading is performed along the direction, and then reading is performed in the direction of the arrow shown in FIG. 7 in order from the positions shown in (2) to (6).

  Therefore, in this embodiment, as shown in FIG. 8, the installation positions of the projector 20 and the imaging device 30 are accumulated in the pixels arranged on the imaging elements included in the imaging device 30 as shown in FIG. Set to the same direction as the reading direction of the received signal. By setting the direction of the imaging grid line to the same direction as the reading direction of the signals accumulated in the pixels arranged on the imaging device, the imaging dot is directed only in one direction from top to bottom on the image. Therefore, it is possible to extract the imaging dots by performing the connecting process from the top to the bottom where the image sensor is read. In other words, since the concatenation process can be performed by the sequential process that is performed each time the signal accumulated in the pixels arranged on the image sensor is read out, it is possible to extract the imaging dots with a small processing load.

  On the other hand, as shown in FIG. 9, the installation position of the projector 20 and the imaging device 30 is determined based on the reading direction of the signals accumulated in the pixels arranged on the imaging elements provided in the imaging device 30. If the dots are arranged in different directions, the imaging dots will move in various directions from top to bottom and from bottom to top on the image, which increases the processing load when extracting the imaging dots. This is not preferable. Therefore, in the present embodiment, as shown in FIG. 8, the installation positions of the projector 20 and the imaging device 30 are accumulated in the pixels arranged on the imaging elements provided in the imaging device 30 in the direction of the imaging grid line. Set to the same direction as the reading direction of the received signal.

  Next, the operation of this embodiment will be described. FIG. 10 is a flowchart showing distance measurement processing according to the present embodiment.

  First, in step S1, the projection pattern generation function of the controller 10 generates and generates a projection pattern composed of a plurality of projection dots for controlling the projection pattern slide 21 provided in the projector 20. The projection pattern is sent to the projector 20. And based on this, the light projection pattern which consists of the light projection dot produced | generated by the light projection pattern production | generation function is set to the light projection pattern slide 21 with which the light projector 20 was equipped.

  In step S <b> 2, a signal for irradiating irradiation light from the projector 20 is sent out by the projector control function of the controller 10. Then, the light projector 20 starts irradiating irradiation light including a light projection pattern including a plurality of light projection dots set in step S1.

  In step S <b> 3, the imaging device 30 captures an image of the front of the vehicle 1 in a state where the projection light 20 is irradiated with irradiation light including a projection pattern including a plurality of projection dots. Then, the image data captured by the imaging device 30 is transmitted to the controller 10.

  In step S4, a signal for ending irradiation of irradiation light by the projector 20 is sent out by the projector control function of the controller 10, and the projector 20 ends irradiation of irradiation light.

  In step S <b> 5, the front of the vehicle 1 is imaged by the imaging device 30 in a state where irradiation light is not irradiated by the projector 20. Then, the image data captured by the imaging device 30 is transmitted to the controller 10.

  In step S <b> 6, the extraction function of the controller 10 performs processing for extracting an image based on the reflection dots generated on the measurement target of the irradiation light irradiated from the projector 20 as an imaging dot. Specifically, the extraction function includes the image data in a state where the irradiation light composed of the projection pattern imaged in step S3 is irradiated and the state where the irradiation light imaged in step S5 is not irradiated. And the difference between the pixels constituting the image data is calculated, and the pixel where the difference is detected is extracted. Then, by performing inter-pixel connection processing on the extracted pixels, it is determined that the region where the pixels from which the difference is detected is continuous is the region where the image based on the reflective dots is captured, and this is captured. Extract as dots.

  In step S7, the association function of the controller 10 associates each imaging dot extracted in step S6 with the light projection dots constituting the light projection pattern set in step S1. Specifically, the association function detects the imaging grid lines that define the upper and lower ends of each imaging dot extracted in step S6, and then detects the projection dot corresponding to this, These are associated with each other.

  In step S8, by the distance measurement function of the controller 10, in step S7, the position of the associated projection dot on the projection pattern slide 21 (that is, the irradiation direction of the irradiation light based on the projection dot) and the imaging dot. The object to be measured from the vehicle 1 by performing distance measurement by triangulation from the position on the imaging screen 31 (that is, the imaging direction on the imaging device 30) and the geometric positional relationship between the projector 20 and the imaging device 30. The distance to the object is measured. At this time, the angle with respect to the imaging grid line is calculated for each imaging dot detected on the imaging screen 31 by the distance measurement function.

  As described above, the distance measurement processing according to the present embodiment is performed.

  In the present embodiment, a straight line connecting the projector 20 and the imaging device 30 on the projection pattern slide 21 when the measurement target is irradiated with light having a projection pattern composed of a plurality of projection dots. A plurality of lines parallel to the projection dots are set as projection grid lines for defining the upper and lower ends of the projection dots. On the other hand, the projector 20 and the imaging device 30 are similarly connected on the imaging screen 31. A plurality of lines parallel to the straight line are set as imaging grid lines, and these are used to associate the projection dots with the imaging dots. Therefore, according to the present embodiment, the projection dots and the imaging dots can be reliably associated with a small processing load, and as a result, the distance to the measurement object can be appropriately measured. .

  In addition, according to the present embodiment, each projection dot constituting the projection pattern is detected on the imaging screen 31 of the imaging device 30 in order to have a different combination of projection grid lines having an upper end and a lower end. It is possible to make a one-to-one correspondence between the imaging dots and the light projection dots with high accuracy.

  Furthermore, according to the present embodiment, as shown in FIG. 8, the direction of the imaging grid line is the same as the reading direction of the signals accumulated in the pixels arranged on the imaging device provided in the imaging device 30. Since the connection processing can be performed by sequential processing that is performed every time the signal accumulated in the pixels arranged on the image sensor is read out, the distance measurement processing can be performed with a small processing load. it can.

  In addition, according to the present embodiment, for each imaging dot detected on the imaging screen 31, the angle with respect to the imaging grid line is calculated. Therefore, the inclination of the measurement object corresponding to each imaging dot with respect to the imaging grid line Can be detected.

  In the above-described embodiment, the projector 20 is the light projecting unit of the present invention, the imaging device 30 is the image capturing unit of the present invention, the extraction function of the controller 10 is the extraction unit of the present invention, and the light projection pattern generation of the controller 10 is performed. The function corresponds to the projection pattern generation means of the present invention, the association function of the controller 10 corresponds to the association means of the present invention, and the distance measurement function of the controller 10 corresponds to the distance measurement means of the present invention.

  As mentioned above, although embodiment of this invention was described, these embodiment was described in order to make an understanding of this invention easy, and was not described in order to limit this invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Vehicle 10 ... Controller 20 ... Floodlight 30 ... Imaging device

Claims (5)

A light projecting means for irradiating the measurement target with light in a predetermined light projecting pattern;
Imaging means for imaging the measurement object;
An extraction means for extracting, as an imaging dot, an area in which the light irradiated to the measurement object by the light projecting means is imaged from the captured image captured by the imaging means;
A plane perpendicular to the optical axis of the light projecting unit is set as a light projecting surface, and a plurality of lines parallel to a straight line connecting the light projecting unit and the imaging unit are set as a light projecting grid line on the light projecting surface. In this case, among the plurality of grid lines, a pattern composed of a plurality of projection dots having a predetermined pair of projection grid lines as both ends is generated as a projection pattern for irradiating light by the projection unit. A light projection pattern generating means;
Association means for associating the imaging dots with the light projection dots based on the positions of the imaging dots extracted by the extraction means on the imaging screen;
Based on the positions of the imaging dots associated with each other on the imaging screen and the positions of the projection dots in the projection pattern, the irradiation direction of the irradiation light by the projection unit, and the imaging direction of the imaging unit, A distance measuring means for measuring the distance to the measurement object ,
The light projecting pattern generating means is characterized in that the plurality of light projecting dots constituting the light projecting pattern have different combinations of light projecting grid lines defining both ends thereof. Distance measuring device. The distance measuring device according to claim 1 ,
On the imaging screen of the imaging means, when a plurality of lines parallel to a straight line connecting the light projecting means and the imaging means are set as imaging grid lines,
The association unit extracts a pair of projection grid lines corresponding to a pair of imaging grid lines defining both ends of the imaging dots, and detects the projection dots defined by the pair of projection grid lines. Thus, the distance measuring device is configured to associate the imaging dots with the projection dots. The distance measuring device according to claim 2 ,
The imaging means includes an imaging element composed of a plurality of imaging pixels,
The distance measuring device according to claim 1, wherein the light projection grid line and the imaging grid line are set to be parallel to a reading direction of the imaging pixel of the imaging element. In the distance measuring device according to claim 2 or 3 ,
The distance measuring means calculates a straight line connecting the contact points of the imaging dot and a pair of imaging grid lines defining both ends of the imaging dot, and based on an angle of the straight line with respect to the pair of imaging grid lines A distance measuring device that detects an inclination state of the measurement object. Irradiate light with a light projection pattern consisting of multiple light projection dots on the measurement target,
A distance measurement method for measuring a distance to the measurement object by imaging the measurement object irradiated with the light,
The light projecting pattern is configured when a plurality of lines parallel to a straight line connecting the light irradiation position and the imaging position are set as grid lines on a light projecting surface that is a surface perpendicular to the optical axis of the light. The plurality of light emitting dots are a plurality of grid lines, each of which has a predetermined pair of light projecting grid lines as both ends , and a combination of the light projecting grid lines defining the both ends is the plurality of light emitting dots . The projection dots shall be different from each other among the projection dots, and based on the positions of the grid lines defining both ends of the projection dots and the positions of the imaging dots on the imaging screen, The measurement is performed based on the position of the associated imaging dot on the imaging screen, the position of the projection dot in the projection pattern, the irradiation direction of the light, and the imaging direction. versus Distance measuring method for measuring the distance to.

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