JP5764888B2 - Distance measuring device and distance measuring method - Google Patents

Description

  The present invention relates to a distance measuring apparatus and a method for measuring a distance to a measurement object by being mounted on a moving object and irradiating light.

  Conventionally, a distance measurement technique for measuring a three-dimensional shape of a measurement object by irradiating the measurement object with light and capturing the image with a camera has been developed.

  Such distance measurement technology irradiates irregular projection patterns with different dot sizes, line thicknesses and positions, and matches the same projection pattern between two images captured by cameras installed at different positions. The distance was measured by searching and triangulation.

  Patent Document 1 is disclosed as an example of such a three-dimensional shape measuring apparatus. In Patent Document 1, an irregular projection pattern is generated using a random number and irradiated from a projector, and the projection pattern is irradiated. The captured subject was imaged with a standard camera and a reference camera. And the correlation process between the image imaged with the reference | standard camera and the image imaged with the reference camera was performed, and the distance image was produced | generated using the parallax of each matched image.

JP 2001-91232 A

 However, in the above-described conventional technology, an irregular projection pattern is generated using random numbers and irradiated from the projector, so when mounted on a moving object such as a robot or a vehicle, the movement of the moving object The projected light pattern to be irradiated sometimes deviates from the measurement object. Then, since the irregular projection pattern is divided between the measurement object and the background, there is a problem that the projection pattern cannot be associated and the distance cannot be measured. In addition, even when the measurement object moves, there is a problem that the distance measurement cannot be performed because the projection pattern does not hit the measurement object.

 Therefore, the present invention has been proposed in view of the above-described circumstances, and provides a distance measuring apparatus and method capable of accurately measuring a distance without interruption while moving even when mounted on a moving object. For the purpose.

Distance measuring device according to the present invention includes an imaging unit for capturing an image of a moving object forward, a light projecting unit for irradiating a projected pattern in front of the moving objects, an imaging measurement object from an image captured by the unit An irradiation light extraction unit that extracts dots of the projection pattern irradiated to the irradiation light; an irradiation direction calculation unit that calculates an irradiation direction of the projection pattern extracted by the irradiation light extraction unit; and an irradiation direction and an imaging direction of the imaging unit. A distance measuring unit that measures the distance from the geometric relationship to the measurement object using the distance between the light projecting unit and the imaging unit, and the projected light projection pattern is captured by the imaging unit. The above-described problem is solved by a configuration in which a plurality of dots are arranged so as to be aligned on a straight line radiated from the vanishing point on the image to be displayed.

According to the distance measuring apparatus and a distance measuring method according to the present invention, the measurement object by irradiating the projection pattern in which a plurality of dots so as to be aligned on a straight line emanating from the vanishing point on the image captured Therefore, even if it is mounted on a moving object such as a robot or a vehicle, the distance can always be measured without interruption.

It is a block diagram which shows the structure of the distance measuring device which concerns on 1st Embodiment to which this invention is applied. It is a figure which shows an example at the time of mounting the distance measuring device which concerns on 1st Embodiment to which this invention is applied to a vehicle. It is a flowchart which shows the process sequence of the distance measurement process by the distance measuring device which concerns on 1st Embodiment to which this invention is applied. It is a figure which shows an example of the light projection pattern irradiated with the distance measuring device which concerns on 1st Embodiment to which this invention is applied. It is a figure for demonstrating the distance measuring method by the distance measuring device which concerns on 1st Embodiment to which this invention is applied. It is a flowchart which shows the process sequence of the distance measurement process by the distance measuring device which concerns on 2nd Embodiment to which this invention is applied. It is a figure which shows an example of the light projection pattern irradiated with the distance measuring device which concerns on 2nd Embodiment to which this invention is applied. It is a figure for demonstrating the distance measuring method by the distance measuring device which concerns on 2nd Embodiment to which this invention is applied.

  Hereinafter, first and second embodiments to which the present invention is applied will be described with reference to the drawings.

[First Embodiment]
[Configuration of distance measuring device]
FIG. 1 is a block diagram showing a configuration of a distance measuring apparatus according to this embodiment.

  As shown in FIG. 1, the distance measuring apparatus 1 according to the present embodiment captures a light projecting unit 2 that irradiates a light projecting pattern in which a plurality of dots are arranged, and an image in a direction in which the light projecting pattern is irradiated. The imaging unit 3, the irradiation light extraction unit 4 that extracts dots of the projection pattern irradiated to the measurement object from the image captured by the imaging unit 3, and the irradiation of the projection pattern extracted by the irradiation light extraction unit 4 An irradiation azimuth calculating unit 5 that calculates the azimuth and a distance measuring unit 6 that measures the distance to the measurement object are provided.

  Here, the distance measuring device 1 according to the present embodiment is mounted on a moving object such as a robot or a vehicle, and the light projection pattern irradiated to the measurement object is imaged by the imaging unit 3, and the light projection pattern is irradiated. The distance from the geometric relationship to the measurement object is measured using the irradiated direction, the imaging direction of the imaging unit 3, and the distance between the light projecting unit 2 and the imaging unit 3.

The light projection unit 2 includes a light projection pattern generation unit 21 that generates a light projection pattern in which a plurality of dots are arranged, a light projection pattern control unit 22 that controls irradiation / non-irradiation of the light projection pattern, and a light projection pattern. And a projector 23 for irradiating the measurement object. The irradiated light projection pattern has a configuration in which a plurality of dots are arranged on a straight line radiated from a vanishing point on an image captured by the imaging unit 3 .

  The projection pattern generation unit 21 reads a projection pattern created in advance based on the arrangement of the projector 23 and the imaging unit 3 from a storage device such as a memory, and transmits the projection pattern to the projection pattern control unit 22.

  The light projecting pattern control unit 22 controls the light projector 23 by outputting an irradiation control signal for controlling irradiation / non-irradiation of the light projecting pattern.

  The projector 23 is a light emitting device for irradiating a projection pattern, and irradiates the projection pattern in the moving direction of the moving object.

  The imaging unit 3 is a video camera or the like that captures an image in the moving direction of a moving object, and continuously captures an image of a region irradiated with a light projection pattern.

  Based on the irradiation control signal output from the projection pattern control unit 22, the irradiation light extraction unit 4 extracts a region where the image luminance value of the image captured by the imaging unit 3 changes brightly as a projection pattern. .

  The irradiation azimuth calculation unit 5 compares the projection pattern dots extracted by the irradiation light extraction unit 4 with the projection pattern generated by the projection pattern generation unit 21, and projects the projection onto the measurement object. The irradiation azimuth is calculated by determining in which direction the dot of the pattern is irradiated.

  The distance measurement unit 6 performs triangulation from a geometrical relationship using the irradiation direction of the projection pattern irradiated to the measurement object, the imaging direction of the imaging unit 3, and the distance between the projector 23 and the imaging unit 3. The distance to the measurement object is measured.

  Next, with reference to FIG. 2, the arrangement of each part constituting the distance measuring apparatus 1 according to the present embodiment will be described. As shown in FIG. 2, when the distance measuring device 1 according to the present embodiment is mounted on a vehicle as an example of a moving object, the projector 23 is incorporated in a door mirror and is configured with a plurality of dots toward the front of the vehicle. Irradiated with a light projection pattern. The imaging unit 3 is installed beside the projector 23 and is incorporated in the door mirror together with the projector 23. And the imaging part 3 images continuously the vehicle front, and images the area | region illuminated by the light projection pattern irradiated from the light projector 23. FIG. The arithmetic unit 25 is disposed in the vehicle interior and measures the distance to the measurement object irradiated with the light projection pattern by performing processing such as distance measurement processing described below.

  Note that FIG. 2 illustrates an example in which the vehicle is mounted on a vehicle. However, the distance measuring device 1 according to the present embodiment is mounted on any moving object that moves in space as long as it is not a vehicle but a robot or the like. It is possible to do.

[Distance measurement procedure]
Next, the procedure of distance measurement processing by the distance measurement apparatus 1 according to the present embodiment will be described with reference to the flowchart of FIG.

  As shown in FIG. 3, in step S <b> 101, a projection pattern created in advance according to the arrangement of the projector 23 and the imaging unit 3 is read from a storage device such as a memory and generated.

Here, the light projection pattern of this embodiment is demonstrated with reference to FIG. As shown in FIG. 4, the projection pattern has a configuration in which a plurality of identification dots are arranged on a plurality of straight lines radiated from vanishing points on the image captured by the imaging unit 3 . In this case, it is composed of dots for specifying in various shapes such as upper and lower triangular patterns (▼, ▲) and square patterns (■). By arranging in this way a specific dot on the straight line which is the vanishing point or et radiation on the image captured by the imaging unit 3, the dot light is sequentially irradiated to even the measurement object as a vehicle moves become.

  Further, the specifying dots are the only patterns that can be discriminated when imaged by the imaging unit 3 with different colors and shapes. In Fig. 4, various specific dots are arranged, including upper and lower triangular patterns (▼, ▲), square patterns (■), and round patterns (●), and all the specific dots can be distinguished. This is the only pattern. In this way, by configuring all the dots for identification with a unique pattern that can be discriminated, it is possible to discriminate in which direction the dot light irradiated to the measurement object is irradiated, and from the captured image An irradiation direction and an imaging direction can be calculated.

  Next, in step S102, the projection pattern generated in step S101 is irradiated in the moving direction of the moving object by turning on the lamp of the projector 23. Then, when the projection pattern is irradiated, the imaging unit 3 captures an image in a state where the projection pattern is irradiated in step S103.

  Next, when the projector 23 is turned off in step S104, the imaging unit 3 captures an image in a state where the projection pattern is not irradiated in step S105. When the image irradiated with the projection pattern and the image not irradiated are captured in this manner, the image when the projection pattern is irradiated is compared with the image when the projection pattern is not irradiated in step S106. To calculate the difference of each pixel. In step S107, the dots for specifying the light projection pattern reflected by the object to be measured are extracted based on the difference calculated in step S106.

Here, the processing described above will be described with reference to FIG. FIG. 5 is a diagram for explaining how the measurement target object is irradiated with the specifying dots when the projection pattern shown in FIG. 4 is irradiated from the vehicle. FIG. 5 shows the relative positional relationship between the vehicle moving from time T0 to time T5 and the measurement object. At time T0, the upper triangular pattern (▲) at the top of the projection pattern. Is irradiated to the measurement object, and then at time T3, the square pattern (■) in the middle of the projection pattern is sequentially irradiated to the measurement object. At time T5, a round pattern (●) in the lower stage of the light projection pattern is sequentially irradiated onto the measurement object. This is because the moving direction of the measurement object on the projection surface is determined by the vehicle mounting position of the projector 23 and the movement of the vehicle, and the identification dot is emitted from the vanishing point on the image captured by the imaging unit 3. By arranging them on the straight line, the measurement object is sequentially irradiated with the specifying dots as the moving object moves.

  Next, in step S108, the identification dot extracted in step S107 is discriminated to calculate the irradiation direction of the identification dot. Since each specifying dot has a different shape, it is possible to easily distinguish and calculate the irradiation direction. Since the irradiation direction of the specifying dot can be calculated from the captured image in this way, distance measurement without interruption is possible.

  When the irradiation direction is thus calculated, in step S109, the imaging direction of the specifying dot is calculated from the captured image position, and the imaging direction, the irradiation direction calculated in step S108, and the projector 23 and the imaging unit 3 are calculated. Measure the distance by triangulation from the geometric arrangement between.

  More specifically, assuming that the irradiation azimuth is θc, the imaging direction is θp, and the distance between the imaging unit 3 and the projector 23 is d, a perpendicular line extends from the measurement object to the straight line A connecting the imaging unit 3 and the projector 23. Lower B. If the distance from the projector 23 to the contact point between the perpendicular B and the straight line A is dc, and the distance from the imaging unit 3 to the contact point between the perpendicular B and the straight line A is dp, the length of the perpendicular B, that is, the measurement object The distance L can be expressed by the following equation.

d = dc + dp
dc = L · tan θc
dp = L · tanθp
Therefore, by solving this equation, the distance L to the measurement object can be calculated.

  When the distance to the measurement object is calculated in this way, the distance measurement process by the distance measurement apparatus 1 according to the present embodiment is completed.

[Effect of the first embodiment]
As described above in detail, according to the distance measuring apparatus according to the first embodiment to which the present invention is applied, the projection pattern in which a plurality of specifying dots are arranged on a straight line radiated from the vanishing point is irradiated. Since the distance to the measurement object is measured by this, even if this distance measurement device is mounted on a moving object such as a robot or a vehicle, the measurement object is sequentially irradiated with dot light, and the distance can always be measured without interruption. it can.

  In addition, according to the distance measuring device, because the dots for identification are configured with a unique pattern that can be distinguished from each other, it is possible to reliably discriminate the dot light irradiated to the measurement object, and to measure accurately. The distance to the object can be measured.

[Second Embodiment]
Next, a second embodiment to which the present invention is applied will be described with reference to the drawings. The configuration of the distance measuring apparatus according to the present embodiment is the same as that of the first embodiment described above, and detailed description thereof is omitted.

[Distance measurement procedure]
The procedure of distance measurement processing by the distance measuring apparatus according to the present embodiment will be described with reference to the flowchart of FIG.

  As shown in FIG. 6, in step S <b> 201, a projection pattern created in advance according to the arrangement of the projector 23 and the imaging unit 3 is read from a storage device such as a memory and generated.

  Here, the light projection pattern of this embodiment is demonstrated with reference to FIG. As shown in FIG. 7, the light projection pattern of this embodiment has a configuration in which measurement dots are further arranged in addition to the specifying dots described in the first embodiment.

As shown in FIG. 7, a plurality of measurement dots are arranged for each of the specifying dots, arranged on a straight line radiated from a vanishing point on the image taken by the imaging unit 3, and the imaging unit 3 has the size of the unit pixel of the image captured. For example, in FIG. 7, six measurement dots S1 to S6 are arranged for one identification dot T. In addition, at least one measurement dot S is arranged below the specification dot T, and the width W of the specification dot T has a width that allows at least two measurement dots S to enter.

  Next, in step S202, the projection pattern generated in step S201 is irradiated in the moving direction of the moving object by turning on the lamp of the projector 23. Then, when the light projection pattern is irradiated, the imaging unit 3 captures an image in a state where the light projection pattern is irradiated in step S203.

  Next, when the projector 23 is turned off in step S204, the imaging unit 3 captures an image in a state where the projection pattern is not irradiated in step S205. When the image irradiated with the projection pattern and the image not irradiated are captured in this way, in step S206, the image when the projection pattern is irradiated is compared with the image when the projection pattern is not irradiated. To calculate the difference of each pixel. In step S207, based on the difference calculated in step S206, the light projection pattern reflected by the measurement object is extracted.

  Next, in step S208, the dot light constituting the extracted light projection pattern is discriminated into a specifying dot and a measurement dot according to the size.

  Here, the processing described above will be described with reference to FIG. FIG. 8 is a diagram for explaining a state in which the light projection pattern is irradiated on the measurement object when the light projection pattern shown in FIG. 7 is irradiated from the vehicle. In FIG. 8, when the vehicle moves from the time T0 to the time T2, a state where the light projection pattern is irradiated to the upright measuring object 80 is shown. At time T0, the specifying dot T and the measuring dots S1, S2 are irradiated to the measuring object 80, and at time T1, a part of the specifying dot T is detached from the measuring object 80 and the measuring dots S1 to S3 are set. The measurement object 80 is sequentially irradiated. At time T2, the specifying dot T and the measuring dot S1 are removed from the measuring object 80, and the measuring dots S2 to S4 are sequentially irradiated onto the measuring object 80.

  As described above, when the measurement dot is sequentially irradiated with the specifying dot and the measurement dot, and the specifying dot and the measurement dot reflected by the measurement target are discriminated, the identification discriminated in step S208 in step S209. For the dot for measurement and the dot for measurement, the identification process with the dot for specification and the dot for measurement one frame before is performed.

  More specifically, the position of the extracted identification dot is identified and associated with the position in the image one frame before, and the transition of the identification dot is traced. At this time, since the specifying dots are formed in a unique pattern that can be discriminated, the specifying dots captured in the image one frame before can be specified. When the specifying dot is specified, each of the measurement dots is discriminated and specified according to the order from the specifying dot. Then, the position where the measurement dot discriminated in step S208 is imaged one frame before is identified and associated, and the transition of the measurement dot is traced.

Next, in step S210, the irradiation direction of the measurement dots associated in step S209 is calculated and held as irradiation direction information. At this time, the newly observed measurement dots have their irradiation directions determined by the adjacent measurement dots arranged on a straight line radiated from the vanishing point on the image picked up by the image pickup unit 3 or by the specifying dots existing above. Identify and hold.

  When the irradiation direction is thus calculated, in step S211, the imaging direction of the measurement dot is calculated from the captured image position, and the imaging direction, the irradiation direction calculated in step S210, the projector 23, and the imaging unit 3 are calculated. Measure the distance by triangulation from the geometric arrangement between.

  When the distance to the measurement object is calculated in this way, the distance measurement process by the distance measurement device according to the present embodiment is completed.

[Effects of Second Embodiment]
As described above in detail, according to the distance measuring device according to the second embodiment to which the present invention is applied, the distance measuring device further includes a measurement dot having a size of a unit pixel of an image captured by the imaging unit, Since a plurality of dots are arranged for each of the specific dots, even when the specific dots are divided and irradiated on the measurement object, the measurement dots are always irradiated to the measurement object, The distance can always be measured without interruption.

  Further, according to the distance measuring device, the specifying dot has a width in which at least two measuring dots are included, and at least one measuring dot is arranged below the specifying dot. Based on the position, the position of the measurement dot arranged below the specification dot can be specified, and thereby the distance to the measurement object can be accurately measured.

  Furthermore, according to this distance measuring device, the dots for measurement and the dots for measurement are discriminated according to the size of the dots, and the dots for measurement are discriminated according to the order from the dots for specification, and each measurement dot is irradiated. Since the irradiation direction is calculated, the position of each measurement dot can be specified, and thereby the distance to the measurement object can be accurately measured.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and even if it is a form other than this embodiment, as long as it does not depart from the technical idea according to the present invention, the design and the like Of course, various modifications are possible.

DESCRIPTION OF SYMBOLS 1 Distance measuring device 2 Light projection part 3 Imaging part 4 Irradiation light extraction part 5 Irradiation direction calculation part 6 Distance measurement part 21 Light projection pattern production | generation part 22 Light projection pattern control part 23 Light projector 25 Calculation unit 80 Measurement object

Claims (6)

A distance measurement device that measures a distance between a measurement object mounted on a moving object that moves on a road surface and installed on the road surface ,
Imaging means for imaging an image in front of the moving object;
A light projecting unit that irradiates the road surface with a light projecting pattern in which a plurality of dots are arranged so as to be arranged on a straight line radiated from a vanishing point on an image captured by the image capturing unit;
Irradiation light extraction means for extracting the dots of the projection pattern irradiated on the measurement object from the image captured by the imaging means;
Irradiation azimuth calculating means for calculating the irradiation azimuth irradiated with the dots of the projection pattern from the dots of the projection pattern extracted by the irradiation light extraction means;
Distance measuring means for measuring the distance from the geometric relationship to the measurement object using the irradiation direction, the imaging direction of the imaging means, and the distance between the light projecting means and the imaging means. A distance measuring device characterized by being.   The distance measurement according to claim 1, wherein the plurality of dots arranged so as to be aligned on a straight line radiated from the vanishing point are identification dots each configured by a unique pattern that can be distinguished. apparatus.   The plurality of dots arranged so as to be arranged on a straight line radiated from the vanishing point further includes a measurement dot having a size of a unit pixel of an image captured by the imaging unit, and the measurement dot is the The distance measuring device according to claim 2, wherein a plurality of the dots for identification are arranged.   4. The distance according to claim 3, wherein the identification dot has a width in which at least two of the measurement dots are included, and at least one measurement dot is disposed below the identification dot. 5. Measuring device.   The irradiation direction calculating means discriminates the specifying dot and the measuring dot according to the size of the dot, discriminates each of the measuring dots according to the order from the specifying dot, and discriminates the measured dot The distance measuring device according to claim 3 or 4, wherein an irradiation direction irradiated with dots is calculated. A distance measuring device including an imaging unit that captures an image in front of a moving object that moves on a road surface and a light projecting unit that irradiates the front of the moving object is used to measure the moving object and a measurement object installed on the road surface . A distance measuring method for measuring the distance between
Projection pattern irradiation step of irradiating the road surface from the projection unit with a projection pattern in which a plurality of dots are arranged so as to be aligned on a straight line radiated from a vanishing point on the image captured by the imaging unit When,
An imaging step of imaging an image ahead of the moving object from the imaging means;
An irradiation light extraction step for extracting dots of the projection pattern irradiated on the measurement object from the image captured in the imaging step;
An irradiation azimuth calculating step for calculating an irradiation azimuth irradiated with the dots of the projection pattern from the dots of the projection pattern extracted in the irradiation light extraction step;
A distance measuring step of measuring a distance from the geometric relationship to the measurement object using the irradiation direction, the imaging direction of the imaging means, and the distance between the light projecting means and the imaging means. A distance measurement method characterized by

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