JP4276360B2 - Stereo imaging system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stereo image capturing system, and more particularly to a stereo image capturing system capable of easily obtaining information and measurement data necessary for obtaining three-dimensional data from a stereo image.
[0002]
[Prior art]
In recent years, line drawings of measurement sites have been created by a combination of a surveying instrument represented by an electronic flat plate and a portable computer. In such a conventional electronic flat plate, a line drawing is drawn on a portable computer using a surveying instrument such as a total station or GPS. Then, when plotting the measurement site, it was charted while looking at the current situation at the site, or separately photographed and charted at the office while looking at them. In aerial photography, etc., the images were taken from stereo images using an analysis plotter. In terrestrial photogrammetry, when three-dimensional measurement is performed from a stereo image, conventionally, photographing, analysis, and measurement are performed with a stereo camera in which the base line length and the camera direction are strictly fixed.
[0003]
[Problems to be solved by the invention]
However, in the conventional technology, the base line length and the like of the stereo camera are fixed, and the imaging range and accuracy (object) are limited. Also, in the past, if measurement was to be performed without fixing the base line or the like, when performing stereo imaging and performing three-dimensional analysis, an image that can be analyzed in stereo can be obtained even when two images are overlapped and captured. It was difficult. That is, in most cases, the image cannot be analyzed, is unstable even if it can be analyzed, has poor accuracy, and is extremely low in reliability. In particular, when a camera is mounted on a balloon, a car, or other moving body, it is very difficult to obtain a highly reliable and analyzable image.
[0004]
[Means for Solving the Problems]
According to the solution of the present invention,
A camera that captures an image of an object by a timing signal indicating timing, and a movable photographing unit on which a reflecting member is mounted;
A measuring unit that is placed at a position away from the imaging unit, emits measurement light toward the reflecting member of the imaging unit, and measures the position of the imaging unit based on the reflected light reflected from the reflecting member;
A shooting position calculation unit that calculates shooting position data based on shooting condition data related to the shooting target;
A driving unit that moves the photographing unit to a predetermined position based on the photographing position data calculated by the photographing position calculating unit;
A movement control unit for controlling the driving unit;
A timing signal is output to the camera of the photographing unit when the position data indicating the position of the photographing unit measured by the measuring unit and the photographing position data calculated by the photographing position calculating unit match or substantially match. A stereo image shooting system including a shooting control unit is provided.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 1 shows a configuration diagram of a first embodiment of a stereo image capturing system. In this embodiment, the photographing unit 10, the image data storage unit 30, the signal processing unit 200, the measurement unit 100, the condition setting unit 70, the photographing position calculation unit 40, the photographing control unit 50, the movement control unit 80, and the driving unit 90 are provided. Prepare.
[0006]
The imaging unit 10 includes a camera that captures an image and an all-around prism. The image data storage unit 30 stores the image data captured by the camera of the imaging unit 10 and the position data measured by the measurement unit 100 in association with each other. The signal processing unit 200 performs three-dimensional measurement / analysis based on stereo imaged image data and position data. The measuring unit 100 uses a total station or the like as a surveying instrument, and measures the position data (measured value) using the prism on the photographing unit 10 as a collimation. Here, automatic measurement is performed by using an automatic collimation total station. The condition setting unit 70 sets shooting conditions such as a shooting range, accuracy, camera standard value, and the like. The shooting position calculation unit 40 calculates an appropriate shooting position based on the shooting target range and required accuracy set by the condition setting unit 70, and shooting conditions such as a camera and a lens. Further, based on the preliminary measurement result of the measurement unit 100, the planned shooting position is calculated and determined. The imaging control unit 50 moves the movement control unit 80 so that the position data (measured value) of the imaging unit 10 measured by the measurement unit 100 and the imaging position data calculated by the imaging position calculation unit 40 match or substantially match. The photographing unit 10 is moved by the driving unit 90. Then, when the measured position data and the calculated shooting position data match or substantially match, a timing signal for shooting is output to the shooting unit 10 and the measurement unit 100. In addition, the imaging control unit 50 gives position data (measurement value) at the timing of imaging to the image data storage unit 30. At this time, the image data photographed from the photographing unit 10 is stored in the image data storage unit 30. The movement control unit 80 gives the movement amount of the photographing unit 10 to the driving unit 90. The drive unit 90 enables the photographing unit 10 to move.
[0007]
FIG. 2 shows a configuration diagram of the photographing unit 10. As the camera 1, a commercially available film camera, digital camera, measurement camera, or the like is used. A large number of prisms are attached in each direction so that the position of the all-round prism 2 can be measured by the measuring unit 100 from anywhere. Further, the photographing unit 10 can be moved by the driving unit 90.
[0008]
Next, FIG. 3 shows a configuration diagram of the drive unit. For example, as shown in FIG. 3A, the drive unit 90 is attached to a car, a caterpillar, a balloon as shown in FIG. can do. Further, the camera 1 of the photographing unit 10 can be provided with a photographing posture position correcting unit as described later, and the obtained acceleration and angular velocity can be cumulatively calculated using a gyro sensor and an inclinometer used there.
[0009]
At least a photographing unit 10 is mounted on a platform for photographing, and an image data storage unit 30, a signal processing unit 200, and the like can be appropriately mounted. Between the platform and the measurement unit 100, signals such as a position for measurement command, measurement data, and the like are transmitted and received by a transmitter / receiver provided in each. These transceivers are attached to the photographing unit 10, the image data storage unit 30, and other appropriate positions. The transmitter / receiver can use an appropriate wireless or wired transmission method in addition to transmission by optical communication using the optical transmitter / receiver.
[0010]
As an example of mounting each component, for example, when a component other than the measuring unit 100 is mounted on the platform, a timing signal and measured position data are transmitted between the platform and the measuring unit 100 by a transceiver. . As another example, the imaging unit 10, the drive unit 90, the movement control unit 80, the image data storage unit 30, and the signal processing unit 200 are mounted on the platform, and the imaging control unit 50, the imaging position calculation unit 40, the condition The setting unit 70 may be mounted on the measurement unit 100 side. In this case, the timing signal, the measured position data, and the control signal of the movement control unit 80 are transmitted between the platform and the measurement unit side by the transceiver. Furthermore, as another example, an appropriate component may be mounted as a block other than the platform and the measurement unit 100 side. In this case, for example, the imaging unit 10, the driving unit 90, and the movement control unit 80 are provided on the platform, while the imaging control unit 50, the imaging position calculation unit 40, the condition setting unit 70, the image data storage unit 30, and the other blocks are provided. The signal processing unit 200 can also be mounted.
[0011]
FIG. 4 is an explanatory diagram showing a state of measurement. As shown in this figure, the photographing unit 10 performs photographing from at least two places in order to perform stereo photographing. Then, using the all-round prism 2 mounted on the photographing unit 10, each photographing position is measured by the surveying instrument of the measuring unit 100. Further, if at least one reference point is arranged on the measurement object, the positional relationship between the camera 1 position up to the object and the photographing unit 10 and the measurement unit 100 can be measured accurately.
[0012]
Next, the automatic measurement operation will be described according to the flowchart. FIG. 5 is a flowchart of automatic measurement. Furthermore, FIG. 6 is an explanatory diagram of a shooting position by automatic measurement.
First, the measurement unit 100 and the platform (imaging unit 10) are installed (S100). The measuring unit 100 is installed at a position where the photographing position of the photographing unit 10 can be seen through the measurement target and does not get in the way. For example, the position shown in the measurement unit 100 of FIG. In addition, it becomes more efficient if it is in the approximate photographing start position. Next, a measurement range (reference position) of an object to be measured, for example, positions a and b in FIG. 6 is measured by the measurement unit 100 (S110). Further, the position of the all-round prism 2 of the photographing unit 10 is measured by the measuring unit 100 (S110). Then, the measurement unit 100 transfers these measurement data to the imaging control unit 50. The condition setting unit 70 sets shooting condition data related to the shooting target in the shooting position calculation unit 40 (S120). Here, the angle of view θ of the lens, the focal length f, the pixel pitch δp of the digital camera, the necessary accuracy δxy in the plane direction, the required accuracy δz in the depth direction, and the like are set. The shooting position calculation unit 40 calculates shooting position data based on these conditions (S130). Here, calculation of shooting position data will be described. For simplicity, it is assumed that the digital camera is parallel to the measurement object. The photographing position calculation unit 40 calculates the photographing position based on the pixel size δp of the digital camera attached to the photographing unit 10, the focal length f of the lens, the angle of view θ, and the required accuracy set in step S 120.
[0013]
For example, assuming that the required accuracy δxy in the plane direction of the measurement object is the shooting distance H,
H = δxy × f / δp (1)
If the depth direction is δz, the baseline length B is
B = H × H × δp / (f × δz) (2)
The shooting range R is
R = 2Htan (θ / 2) (3)
Is calculated by The overlap range O is
O = R−B ▲ 4 ▼
It becomes.
[0014]
From these, the number of shots is
If n = area / O remainder ≠ 0, then n + 1 (5)
It becomes.
Therefore, the total shooting range is
if remainder = 0, all areas = O × n + 2B (6)
if remainder ≠ 0, all areas = O × (n + 1) + 2B (7)
In the measurement ranges a and b, the shooting positions are determined by setting them as overlap regions. When the remainder is not 0, it is not limited to the equation (7). Also, the overlap method is not limited to this. In steps S120 and S130, if the photographing range is known in advance, conditions may be set in advance and roughly calculated in a step prior to this step. When it is desired to select a lens or a camera based on the required accuracy or on-site conditions, the optimum conditions are determined and determined from these conditions before the field work.
[0015]
Returning to the flowchart, the description will be continued. When the shooting position data is calculated in step S130, the shooting control unit 50 compares the previously measured position data of the platform (shooting unit 10) with the shooting position data calculated by the shooting position calculation unit 40 (S140). If both match or substantially match, it is determined that the imaging signal is appropriate (OK), and the process proceeds to step S180. If not OK, the process proceeds to the next step S145. In step S <b> 145, the photographing control unit 50 calculates a displacement (movement amount) between the measured position data (measured value) of the platform including the photographing unit 10 and the planned photographing position calculated by the photographing position calculation unit 40. Next, the imaging control unit 50 sends the movement amount to the movement control unit 80. The movement control unit 80 moves the photographing unit 10 to the photographing position by the driving unit 90 based on an instruction from the photographing control unit 50 (S150). When the movement is completed, the movement control unit 80 sends a movement end signal to the imaging control unit 50 as necessary. Next, the measurement unit 100 measures the position of the platform (imaging unit 10) (S160). The imaging control unit 50 compares the received position data (measured value) of the platform (imaging unit 10) with the imaging position data (calculated value) calculated by the imaging position calculation unit 40 (S170). If both match or substantially match, it is determined that the imaging signal is appropriate (OK), and the process proceeds to step S180. If not OK, the process proceeds to step S145. If the photographing position is OK in step S140 or S170, photographing is performed by the photographing unit 10 (S180). At this time, if the image data storage unit 30 has a system configuration, the captured image data and the position data (measurement value) are simultaneously written in the image data storage unit 30. Next, if the number of shots satisfies the condition, the shooting is terminated, and if the next shooting is necessary, the process proceeds to step S145 (S190). When shooting is finished, the signal processing unit 200 performs three-dimensional measurement. As described above, a stereo image can be automatically captured.
[0016]
Here, FIG. 7 shows a detailed flowchart of the position measurement of the photographing unit 10 in steps S110 and S160 in the flowchart of automatic measurement.
[0017]
When moving to the shooting position in step S100 or S150 of FIG. 5, a timing signal is sent from the platform side to the measurement unit 100 in accordance with the shooting timing (S41). Next, the position of the photographing unit 10 is measured by the measuring unit 100 (S45). That is, the measurement unit 100 that has received the position measurement command signal automatically collimates and measures the position of the all-round prism 2 of the imaging unit 10. After measuring the position, the measurement unit 100 sends measurement position data to the platform side (S46). The image data storage unit 30 receives the measurement position data and stores it in association with the imaged image data (S48). The above operations can be performed automatically.
[0018]
Here, the basic principle of the three-dimensional measurement by the stereo method is shown. FIG. 8 shows an explanatory diagram of the stereo method. Here, for the sake of simplicity, two identical CCD cameras are used. Each optical axis is parallel and the distance a from the principal point of the camera lens to the CCD surface is equal. Further, it is assumed that the CCD is placed at a right angle to the optical axis. The principle of the stereo method will be described below using these conditions.
[0019]
Let L be the distance between the two optical axes (base line length). The following relationship exists between the coordinates of the points P ₁ (x ₁ , y ₁ ) and P ₂ (x ₂ , y ₂ ) on the object.
x ₁ = ax / z (1)
y ₁ = y ₂ = ay / z (2)
x ₂ −x ₁ = a × L / z (3)
However, the origin of the entire coordinate system (x, y, z) is taken as the lens principal point of the camera 1. Z is obtained from equation (3). From these results, x and y are obtained from the equations (1) and (2).
[0020]
When performing stereo shooting, the shooting must be such that a stereo model can be formed from the two acquired images (overlapping images). Furthermore, in order to improve the measurement accuracy, it is necessary to shoot under conditions that are as appropriate as possible. For this purpose, the camera 1 on the photographing unit 10 is controlled in three axial directions of x, y, and z, and can be further moved up and down, and the photographing posture position correcting unit 6 having a variable lens magnification is provided on the photographing unit 10. It can be provided in the camera 1.
[0021]
FIG. 9 is a configuration diagram of a photographing unit having a photographing posture position correcting unit. This configuration includes a camera 1 and a photographing posture position correction unit 6.
The photographing posture position correcting unit 6 measures the posture and orientation of the camera 1 with a sensor (such as a gyroscope) and corrects the posture and orientation. As a result, it is possible to perform highly reliable measurement with the data of the photographing data position maintained so that stereo measurement can be easily performed on the measurement object. Alternatively, automatic three-dimensional measurement can be performed by measuring the posture and orientation of the camera 1 with these sensors and calculating and correcting the posture and orientation in the signal processing unit 200. Further, the photographing posture position correction unit 6 includes a sensor unit that measures the triaxial direction (azimuth and tilt angle) and a movable unit that is variable in the triaxial and vertical directions, and can also control the magnification of the camera lens. .
[0022]
The measurement in the three-axis direction is performed by using various posture sensors such as an inclinometer and a direction meter. Alternatively, the triaxial direction may be corrected by placing the camera 1 of the photographing unit 10 on the leveling table. For the vertical direction and magnification correction, these sensors can be used, or the GPS 500 or the like can be used. However, by using the measurement value of the measurement unit 100, it can be corrected with higher accuracy.
[0023]
These are described below. FIG. 10 is an explanatory diagram for vertical correction. As shown in FIG. 10A, when there is a difference in height between two shooting positions, the upper and lower ranges to be shot are different, resulting in an image that is defective in measurement. When the position of the imaging unit 10 is measured by the measurement unit 100, the height difference is known. The photographing posture position correcting unit 6 moves the camera 1 to an appropriate height as shown in FIG. 10B by moving the camera 1 up and down based on the three-dimensional data.
[0024]
FIG. 11 is an explanatory diagram for correction in the horizontal (left / right) direction. As shown in FIG. 11 (a), the overlapping portion decreases as it moves in the horizontal direction. It is only necessary that the photographing unit 10 can be controlled well at a predetermined position. However, when the photographing unit 10 cannot be held at an appropriate position for some reason, the camera 1 is directed toward a predetermined measurement range and photographing is performed (FIG. 11B). Since the orientation can be known by the gyro of the imaging position correction unit 6, an appropriate direction is calculated based on this and the imaging position measured by the measurement unit 100, and the camera 1 of the imaging unit 10 is directed in that direction.
[0025]
FIG. 12 is an explanatory diagram for correcting the swing direction (tilt). When the traveling direction is tilted up and down or left and right, the photographed images are as shown in FIGS.
The up-down direction is a case where the photographing unit 10 is in a state as illustrated in FIG.
In order to avoid these problems, the tilt of the camera 1 is measured by an inclinometer in the up-down and left-right directions of the photographing posture position correction unit 6 and corrected for photographing.
[0026]
FIG. 13 is an explanatory diagram for correcting the magnification. As shown in FIG. 13A, a problem occurs when the magnifications of the two images are different. For example, when the second image has to be photographed at the positions of the photographing unit 10 and the photographing unit 10 ′ in FIG. 13B, it cannot be photographed at the photographing unit 10 ′ for some reason, and the photographing unit 10 ′. There are cases where you come to the position of '. In this case, since the distance from the photographing unit 10 to the measurement object is known by the measuring unit 100, the photographing posture position correcting unit 6 adjusts the magnification of the lens of the camera 1. As a result, the difference in magnification between the two images is corrected, and shooting is performed with the measurement range appropriately set.
[0027]
As described above, by providing the photographing posture correction unit 6 in the camera 1 of the photographing unit 10 and using the measurement values of the various posture sensors and the measurement unit, it is possible to obtain photographing conditions suitable for stereo photographing.
[0028]
Next, obstacle detection will be described. When there is an obstacle at the photographing position in the range to be measured, the non-prism total station (TS) is used in the measurement unit 100, and it is possible to shoot while avoiding the obstacle by the following procedure.
[0029]
FIG. 14 shows a measurement flowchart for obstacle detection. FIG. 15 is an explanatory diagram of obstacle detection. This obstacle detection process can be appropriately executed before or during the automatic measurement process. Hereinafter, a description will be given according to the flowchart of FIG.
First, the measurement unit 100 and the platform (imaging unit 10) are set to appropriate positions (S200). The condition setting unit 70 sets shooting conditions (S210). At this time, in addition to the imaging parameters set in step S110 of FIG. 5, the measurement target ranges a to b (see FIG. 6) are roughly input. The reference position of the measurement range is measured by the non-prism TS (S220). As long as the measurement target ranges a to b are input, the reference position of the measurement range may be either one or both as long as the start point and the end point are distinguished. Furthermore, in order to ensure the measurement, the position of the photographing unit 10 is also measured here. However, when there is no reflective object as large as the prism in the measurement object, the position of the imaging unit 10 may be measured by automatic scanning in the next step S230. The position of the imaging unit 10 is detected by the all-round prism 2 where the light received by the non-prism TS is the strongest. However, the work can be shortened (scanning detection time) by measuring the position of the platform (photographing unit 10). Next, the non-prism TS is automatically scanned within the measurement range (S230). At this time, the obstacle position (area 300 in FIG. 15) is automatically detected. Obstacle detection can be performed based on a point where the distance measurement values by the non-prism TS are greatly discontinuous (lines c and d in FIG. 15) and the continuity of the distances. Next, the shooting position is calculated from the shooting conditions and the measurement range reference position (S240). After the photographing position is calculated, it is calculated whether the obstacle detection range and the photographing position are not overlapped, and further, there is no obstacle on the planned moving route. If the shooting position and the obstacle overlap, an equivalent shooting position is determined from the shooting position and the lens magnification (for example, the position 10 ′ of the shooting unit in FIG. 15). Adjust to the wide-angle side when approaching the object and to the telephoto side when moving away. When the adjustment cannot be completed, the angle of the camera 1 in the horizontal direction is further calculated, and the camera 1 is moved in the horizontal direction as shown in FIG. If there is an obstacle on the shooting position movement route, the vehicle is moved by setting the route before the obstacle as an avoidance route. The subsequent processing is the same as the processing from step S140 of the automatic measurement flowchart of FIG.
[0030]
As described above, according to the present invention, it has become possible to easily and reliably perform what has been difficult to perform stereo photography for three-dimensional measurement, and can be further automated.
[0031]
【The invention's effect】
According to the present invention, as described above, when three-dimensional measurement is performed with a normal camera, a stereo image that is stable, reliable, and accurate can be easily acquired.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of automatic measurement.
FIG. 2 is a configuration diagram of a photographing unit.
FIG. 3 is a configuration diagram of a drive unit.
FIG. 4 is an explanatory diagram of a state of measurement.
FIG. 5 is a flowchart of automatic measurement.
FIG. 6 is an explanatory diagram of a shooting position.
FIG. 7 is a flowchart of position measurement.
FIG. 8 is an explanatory diagram of a stereo method.
FIG. 9 is a configuration diagram of a camera of a photographing unit.
FIG. 10 is an explanatory diagram of vertical direction correction.
FIG. 11 is an explanatory diagram of left-right direction correction.
FIG. 12 is an explanatory diagram of swing direction (tilt) correction.
FIG. 13 is an explanatory diagram of magnification correction.
FIG. 14 is a flowchart of obstacle detection.
FIG. 15 is an explanatory diagram of measurement when an obstacle is detected.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Image | photographing part 30 Image data memory | storage part 40 Image | photographing position calculating part 50 Image | photographing control part 70 Condition setting part 80 Movement control part 90 Drive part 100 Measuring part 200 Signal processing part

Claims (11)

A movable photographing unit on which a camera for capturing an image of an object by a timing signal indicating timing and a reflecting member are mounted;
A measuring unit that is placed at a position away from the imaging unit, emits measurement light toward the reflecting member of the imaging unit, and measures the position of the imaging unit based on the reflected light reflected from the reflecting member;
A shooting position calculation unit that calculates shooting position data based on shooting condition data related to the shooting target;
A driving unit that moves the photographing unit to a predetermined position based on the photographing position data calculated by the photographing position calculating unit;
A movement control unit for controlling the driving unit;
A timing signal is output to the camera of the photographing unit when the position data indicating the position of the photographing unit measured by the measuring unit and the photographing position data calculated by the photographing position calculating unit match or substantially match. A stereo image shooting system including a shooting control unit. The stereo image capturing system according to claim 1,
The camera of the above shooting unit performs stereo shooting in at least two places,
The above-mentioned measurement part measures the position of the photoed at least 2 places, The system for stereo image photography characterized by the above-mentioned. The stereo image shooting system according to claim 1 or 2,
The camera of the photographing unit can change the photographing condition of at least one of direction, up / down, and magnification so as to maintain a condition suitable for stereo photographing according to the movement of the driving unit. Stereo image shooting system further equipped with. The stereo image shooting system according to any one of claims 1 to 3,
The camera of the photographing unit is configured to be capable of adjusting the vertical direction of the camera as a photographing condition so as to maintain conditions suitable for stereo photographing according to the level of movement by the driving unit. A featured stereo image shooting system. The stereo image shooting system according to any one of claims 1 to 4,
The camera of the photographing unit is configured to be capable of adjusting a horizontal direction of the camera as a photographing condition so as to maintain a condition suitable for stereo photographing according to a distance moved by the driving unit. Stereo image shooting system. The stereo image capturing system according to any one of claims 1 to 5,
The camera of the photographing unit is configured to be able to adjust the direction of the swing direction of the camera as a photographing condition so as to maintain conditions suitable for stereo photographing according to the inclination of the photographing unit when moved by the driving unit Stereo image shooting system characterized by the above. The stereo image capturing system according to any one of claims 1 to 6,
The camera of the photographing unit is configured to be capable of adjusting a magnification of the camera as a photographing condition so as to maintain a condition suitable for stereo photographing according to a distance from the photographing target to the camera. Image shooting system. The stereo image capturing system according to any one of claims 1 to 7,
The measurement unit is configured to perform preliminary measurement to detect an obstacle near the shooting target range and the shooting position, and based on the result of the preliminary measurement, the shooting position calculation unit calculates and determines the planned shooting position. Stereo image shooting system characterized by the above. The stereo image shooting system according to any one of claims 1 to 8,
The stereo image capturing system, wherein the measuring unit is further configured to send position data of the measured capturing position to the capturing unit side. The stereo image shooting system according to any one of claims 1 to 9,
A stereo image capturing system further comprising an image storage unit for storing the position data measured by the measuring unit and the captured image data captured by the camera of the capturing unit in association with each other. The stereo image capturing system according to any one of claims 1 to 10,
At least the photographing unit, the driving unit, and the movement control unit are mounted on a platform for photographing,
A stereo image capturing system further comprising a transceiver for transmitting data between the platform and the measurement unit.

Images