Camera device and manufacturing system for selective outputting of images based on rotational position of the camera device

A camera device is equipped with at least one imaging unit for imaging a subject, a rotary motor for rotating the imaging unit at a prescribed rotation speed, an output unit for outputting images taken by the imaging unit, and a body which incorporates the imaging unit, the rotary motor, and the output unit. The output unit outputs at least one image, among the images, taken at an imaging position where the imaging unit and the subject are approximately parallel with each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2019-103209 filed on May 31, 2019, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a camera device for imaging a subject and a manufacturing system.

BACKGROUND ART

A imaging element is known that is employed in a manufacturing system such as a factory line and is equipped with an imaging unit for imaging a work passing through an imaging range being conveyed by a conveying machine, an illumination unit for illuminating the work passing through the imaging range with light, and a control unit for controlling the imaging unit and the illumination unit (refer to Patent document 1, for example). This imaging element is equipped with a first illumination unit having an opening and a second illumination unit having an opening that is smaller than the opening of the first illumination unit. The imaging element captures a moving work by executing a first imaging process of acquiring an image including a portion formed by reflection light coining from a mark provided in the work from an image taken by turning on only the second illumination unit and a second imaging process of acquiring an image including the work from an image taken by turning on only the first illumination unit on the basis of a result of the first imaging process.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

However, the imaging element disclosed in above Patent document 1 is large in size because it is equipped with the plural illumination units. Furthermore, in the above imaging element, since the imaging unit has a high shutter speed, a large number of images are taken, image processing takes long time, and a heavy computation load occurs. As a result, a manufacturing system using such an imaging element may suffer a problem that a cycle time is made long (e.g., a line operation speed is made slow).

The concept of the present disclosure has been made in view of the above circumstances and an object of the disclosure is therefore to provide a camera device and a manufacturing system capable of performing image processing efficiently and acquiring a clear image simply in a short time and thereby increasing the production efficiency.

This disclosure provides a camera device including at least one imaging unit which captures a subject; a rotary motor which rotates the imaging unit at a prescribed rotation speed; an output unit which outputs images captured by the imaging unit; and a body which incorporates the imaging unit, the rotary motor, and the output unit. The output unit outputs at least one image, among the images, captured at an imaging position where the imaging unit and the subject are approximately parallel with each other.

The disclosure also provides a manufacturing system including a camera for imaging a subject and an image processing device which is communicably connected to the camera. The camera transmits at least one image taken at an imaging position where the subject and at least one imaging unit being rotated at a prescribed rotation speed are approximately parallel with each other; and the image processing device analyzes a state of the subject on the basis of the at least one image received from the camera and outputs an analysis result.

The disclosure makes it possible to acquire a clear image simply in a short time and thereby increase the production efficiency.

DESCRIPTION OF EMBODIMENTS

Background of Conception of First Embodiment

Patent document 1 discloses an imaging element that is employed in a manufacturing system such as a factory line and obtains an image of a subject (work) having a marker that reflects light shining on it by imaging the subject having the marker by illuminating the subject passing through an imaging range with light. An imaging unit of this imaging element has a high shutter speed. This imaging element can image many subjects being conveyed by a conveying machine and performs image processing on them. However, in the imaging element, because of a large number of images to be subjected to the image processing, a long time is taken to perform the image processing, that is, the imaging element suffers a heavy computation load. As a result, a manufacturing system using such an imaging element may suffer a problem that a cycle time is made long (e.g., a line operation speed is made slow).

The concept of the present disclosure has been made in view of the above circumstances and an object of the disclosure is therefore to provide a camera device and a manufacturing system capable of performing image processing efficiently and acquiring a clear image simply in a short time and thereby increasing the production efficiency.

Camera devices and manufacturing systems according to specific embodiments of the disclosure will be hereinafter described in detail by referring to the drawings when necessary. However, unnecessarily detailed descriptions may be avoided. For example, already well-known items may be refrained from being described in detail and constituent elements having substantially the same ones already described may be refrained from being described redundantly. This is to prevent the following description from becoming unnecessarily redundant and thereby facilitate its understanding by those skilled in the art. The following description and the accompanying drawings are provided to allow those skilled in the art to understand this disclosure sufficiently and they are not intended to restrict the subject matter described in the claims.

First Embodiment

FIG. 1is a perspective view of an example inspection device according to a first embodiment. A manufacturing system according to the first embodiment is configured so as to include an inspection cart10which is the example inspection device. The inspection cart10is equipped with a camera unit30as an example camera device and moves on a rail80.

The inspection cart10can move freely along the rail80which extends straightly. The rail80may be a running lane. For example, the rail may be an inspection lane installed alongside a factory line, a conveyance lane dedicated to loads, a lane of a road, a railroad, or the like. The rail is not limited to a straight one, that is, may be curved. The rail80is laid in the longitudinal direction of the lane at its center.

The inspection cart10performs inspection while imaging the rail80or subjects Wk (e.g., works) disposed on the rail80while moving on the rail80. Equipped with a drive device inside, the inspection cart10is a self-propelled cart that runs by driving wheels. The inspection cart10may be a cart that runs by driving wheels that are kept in contact with the rail80by sandwiching the rail80from both sides. Alternatively, the inspection cart10may be moved being driven by an external drive device.

The inspection cart10inspects states of the rail80(e.g., finds presence/absence of a scratch, a deteriorated portion, or a damaged portion formed on the rail80). The inspection cart10has an approximately box-shaped case10z. Devices necessary for inspection of the rail80are provided inside the case10z. It goes without saying that the shape of the case10zis not limited to a box-like shape as mentioned above.

FIG. 2is a perspective view showing an E-E cross section of the inspection cart10shown inFIG. 1.FIG. 3is an E-E sectional view of the inspection cart10shown inFIG. 1. The inspection cart10is connected to a camera control unit50so as to be able to communicate with it and is configured so as to include, inside the case10z, a camera unit30, an encoder60, wheels65, etc.

Directions as coordinate axes are defined as follows. The X direction is defined as a movement direction of the inspection cart10(may be the camera unit30or the subjects Wk). The Y direction is defined as a direction that is perpendicular to the X direction in a surface that is captured by the camera unit30. The Z direction is a direction that is perpendicular to the surface that is captured by the camera unit30. Coordinate axes will be defined in similar manners in following embodiments.

A camera control unit50as an example image processing device, which serves to control the camera unit30, is configured using, for example, a CPU (central processing unit). an MPU (micro processing unit), or a DSP (digital signal processor). The camera control unit50generates, at a prescribed frame rate (e.g., 60 fps or 120 fps), data (frames) of an image taken in the form of RGB (red, green, and blue) signals, YUV (luminance and color differences) signals, or the like that can be recognized by humans by performing prescribed signal processing on an image signal received from the camera unit30. The camera control unit50performs image processing on the basis of a received image, taken by the camera unit30, of a surface of the rail80or subjects Wk (e.g., works) disposed on the rail80. The camera control unit50judges whether an abnormality exists in the rail80or a subject Wk (e.g., a scratch, a deteriorated portion, or a damaged portion formed on a surface) and outputs a judgment result.

The encoder60is an encoder for detection of a speed that detects a rotational position of a rotation axis of one wheel65of the inspection cart10and detects a speed of the inspection cart10on the basis of the number of revolutions per unit time. The encoder60can also detect a position of the inspection cart10corresponding to a pre-specified distance of the rail80on the basis of a rotational position of the rotation axis of the wheel65. The encoder60may be either an absolute encoder capable of detecting an absolute rotational position or an incremental rotary encoder capable of detecting a relative rotational position. The camera unit30may be equipped with a speed sensor in place of the encoder60.

FIG. 4is a side view showing an example appearance of the camera unit30.FIG. 5is an F-F sectional view of the camera unit30shown inFIG. 4. The camera unit30is configured in such a manner that a drum31, a wireless power reception unit32, and a wireless power supply unit34are laid on one on another coaxially.

In a side wall (circumferential wall) pf the drum31, openings are formed. A camera head35is disposed in the opening of the drum31. A camera head35is disposed in the opening of the drum31. The camera head35is disposed so as to be able to capture the rail80or the subject Wk through the opening formed in the circumferential wall of the drum31. The camera head35captures the subject Wk at a high shutter speed.

The wireless power reception unit32has a recess which is a recessed central portion. On the other hand, the wireless power supply unit34has a projection which is a projected central portion. The projection of the wireless power supply unit34is fitted in the recess of the wireless power reception unit32, whereby wireless power supply to each of an illumination unit33, the camera head35, and a rotary motor37is made possible. The thickness of the camera unit30can be reduced because the wireless power reception unit32and the wireless power supply unit34have the above structures. The wireless power reception unit32and the wireless power supply unit34transmit and receive signals such as a drive signal for the drum31and an image signal of the camera head35. Having the above configuration, the camera unit30employed in the first embodiment prevents a harness43(seeFIGS. 8 and 9) for electrical connection of the camera head35and power-supply-side members from being twisted by rotation of the drum31.

FIG. 6is a perspective view showing an example rotation direction of the drum31. The drum31employed in the first embodiment may be shaped like either a circular ring having a central hole or a cylinder having flat side surfaces. The drum31can rotate around its rotation axis with respect to the wireless power reception unit32and the wireless power supply unit34. A drive mechanism for rotating the drum31may be provided either inside or outside the camera unit30. For example, the drum31may be connected to the shaft of a motor (not shown) directly or via gears and driven rotationally as the motor rotates. Alternatively, the drum31may either be in contact with a member vibrated by ultrasonic waves and driven rotationally by vibration produced by an ultrasonic motor or be formed as a rotor of a motor and driven rotationally by its stator.

Although a case that the drum31in the first embodiment will be described as one that is rotated in one direction, the drum31may be one that is rotated in the normal direction and the reverse direction repeatedly.

FIG. 7is a perspective view showing an example appearance of a camera unit30A. The camera unit30A shown inFIG. 7is configured in such a manner as to include the illumination unit33in an integrated component in addition to the camera unit30. Alternatively, the illumination unit33may be provided on the inspection cart10so as to be able to illuminate an imaging range of the camera head35.

The lighting unit33is formed in a substantially rectangular plate shape, and illuminates an imaging range of the camera head35. The illumination unit33provides LED (light-emitting diode) illumination, IR (infrared) illumination, or the like. The illumination unit33illuminates a subject to be captured by the camera head35. The illumination unit33is not limited to the case of providing LED illumination or IR illumination and may employ an EL (electroluminescence) device, a fluorescent lamp, a white lamp, a halogen lamp, a xenon lamp, or the like.

The wireless power reception unit32and the wireless power supply unit34of the camera unit30A shown inFIG. 7transmit and receive signals such as a drive signal for the drum31and an image signal of the camera head35by wireless power supply. Having this configuration, the camera unit30A prevents a harness of the camera head from being twisted by rotation of the drum31. The wireless power supply method may be any of an electromagnetic coupling method, a magnetic resonance method, and an electromagnetic induction method.

FIG. 8is a perspective view showing an example internal structure of the camera head35.FIG. 9is a side view showing the example internal structure of the camera head35. The camera head35as an example imaging unit is housed in a lens barrel (not shown) and is configured so as to include an imaging lens41, an imaging element42, and a harness43. The camera head35shown inFIGS. 8 and 9has an air layer between the imaging lens41and the imaging element42, whereby the focal length is adjusted. The camera head35is not limited to a visible light camera, and may be an infrared camera that can emit near infrared light and receive resulting reflection light to enable imaging, for example, during the nighttime or in a dark place.

The imaging lens41focuses light coming from outside the camera unit30(camera head35) through an opening of the drum31and images it on a prescribed imaging surface of an image sensor (imaging element42). The imaging lens41may be either a fixed lens having a constant focal length or a zoom lens whose focal length is adjustable.

The imaging element42is a solid-state imaging element such as a CCD (charge-coupled device) or a CMOS (complementary metal-oxide semiconductor) sensor. The imaging element42converts the focused and imaged optical image into an electrical signal and outputs a resulting video signal.

The harness43connects the camera head35and the wireless power reception unit32to each other electrically. The harness43supplies power to the camera head35and transmits various signals such as a control signal and a video signal (image taken) to and from the imaging element42. The harness43may be either plural signal lines or a flexible wiring board (FPC: flexible printed circuits).

FIG. 10is a block diagram showing an example internal configuration of a manufacturing system according to the first embodiment. The manufacturing system according to the first embodiment is configured so as to include the inspection cart10as an inspection device and a camera control unit50. Units and components relating to control such as wheels for driving the inspection cart10are omitted inFIG. 10.

The inspection cart10incorporates a camera unit30for imaging an inspection subject, that is, a rail80or a subject Wk on the rail80. The inspection cart10is configured so as to include an encoder60and the camera unit30. The inspection cart10may further be equipped with a Hall element capable of detecting a current position of the inspection cart10in a movement range (i.e., inspection range), set in advance by a user, of the rail80.

The encoder60detects a movement speed of the inspection cart10and transmits it to the camera control unit50.

The camera unit30is installed in the inspection cart10in such a manner as to be able to capture the rail80or subjects Wk on the rail80by means of the camera head35. Although the camera unit30employed in the first embodiment is movable being mounted in the inspection cart10, the concept of the disclosure is not limited to this case. For example, the camera unit30may be equipped with a motor as a moving means for imaging rail80or subjects Wk on the rail80. The camera unit30is configured so as to include a rotary motor37, a power supply unit40, an imaging lens41, and an imaging element42.

The rotary motor37rotationally drives the camera unit30at a prescribed rotation speed around the rotation axis shown inFIGS. 6 and 7. A rotation speed of e rotary motor37is calculated and set by the camera control unit50.

The power supply unit40is configured so as to include a wireless power reception unit32and a wireless power supply unit34. The power supply unit40supplies power to an illumination unit33(not shown), the camera head35, the rotary motor37, etc.

The camera control unit50controls the inspection cart10and the camera unit and acquires an image taken (image signal) from the camera unit30. The camera control unit50is configured so as to include a motor control unit51, a camera control unit52, an LED control unit53, and a power source unit54.

The motor control unit51transmits a control signal for controlling the movement speed of the inspection cart10to a motor (not shown) for driving the inspection cart10. The motor control unit51receives detected speed information of the inspection cart10from the encoder60. The motor control unit51compares the received speed information with a movement speed indicated by the transmitted control signal and manages the movement speed of the inspection cart10. The motor control unit51may transmit a control signal that is set by the user.

The motor control unit51transmits a control signal for controlling the rotation speed of the camera unit30to the rotary motor37. As for the motor control unit51, a frame rate of the camera head35and a distance between the camera head35and a subject Wk are set by the user in advance. The motor control unit51calculates a rotation speed of the rotary motor37so that the relative speed between the camera head35and the subject Wk becomes equal to 0 on the basis of these set values, a movement direction and speed of the inspection cart10, and a movement direction and speed of the subject Wk. The motor control unit51transmits a control signal generated on the basis of the calculated rotation speed to the rotary motor37.

The camera control unit52controls the shutter speed, the imaging start timing, and the imaging end timing of the camera head35. The camera control unit52receives an image signal of an image taken by the camera head35. The camera control unit52performs image processing on the basis of an image taken (image signal) received from the camera unit30. The camera control unit52judges whether a portion of the rail80or a subject Wk existing in an image taken has an abnormality (e.g., scratch, fatigue, or foreign substance) and outputs a judgment result.

The camera control unit50may measure a current position of the inspection cart10on the basis of movement information received from the encoder60and a movement range (e.g., inspection range) that was set by the user in advance. Where the inspection cart10is equipped with a component such as a Hall element capable of detecting current position information, the camera control unit50may estimate a current position of the inspection cart10on the basis of this position information. Where the position of subjects Wk is fixed, the camera control unit50may control the imaging timing of the camera head35(i.e., an image to be received) on the basis of a current position of the inspection cart10measured or estimated on the basis of a movement range or position information.

The LED control unit53controls an illumination unit33provided in or for the inspection cart10or the camera head35.

When turned on by the user, the power source unit54supplies power to the individual units and components of the camera control unit50and the camera unit30.

FIG. 11is a diagram showing an example of how a subject Wk is captured by the camera head35. In the example of imaging shown inFIG. 11, the inspection cart10is moving straightly in a direction MV1. The camera unit30is rotating in a direction MM1around the rotation axis of the drum31. A position Oj (described later) on the subject Wk being captured by the camera head35is a position at which the camera head35is focused. As the inspection cart10moves and the camera unit30rotates, the camera head35is moved so as to form a trace that is shaped like a cycloid curve. The inspection cart10is omitted inFIG. 11to describe positional relationships between the drum31, the subject Wk, and the camera head35that is imaging the subject Wk.

The imaging lens41of the camera head35focuses, with a prescribed angle of view Ar, light coming from the subject Wk and forms an optical image of the subject Wk located at the position Oj on the imaging surface of the imaging element42. The camera unit30starts transmitting an image of the subject Wk to the camera control unit50when or immediately before the relative speed between the camera head35and the subject Wk becomes equal to 0. A time during which the camera unit30transmits images of the subject Wk to the camera control unit50is from immediately before the above-mentioned relative speed becomes equal to 0 to a time when it can no longer be regarded as being equal to 0. That is, images transmitted from the camera head35are ones that are taken while the camera head35can be regarded as being parallel with the subject Wk (in other words, the relative speed between the camera head35and the subject Wk is approximately equal to 0).

The camera head35may transmit images taken according to a signal indicating imaging timing received from the camera control unit50.

The subject Wk shown inFIG. 11may be one other than the rail80along which the inspection cart10can move, such as a work that is conveyed by a belt conveyor (described later). That is, the movement speed of the subject Wk need not be equal to 0.

FIG. 12is a diagram showing an example of how the angle of view of the camera head35varies as it moves in a time taken by imaging. Referring toFIG. 12, the inspection cart10(not shown) moves in a direction MV1. InFIG. 12, as inFIG. 11, The inspection cart10and the rail80are omitted to describe positional relationships between the drum31, the subject Wk, and the camera head35that is imaging the subject Wk.

A locus of a point at which the camera head35is focused (i.e., a position Oj that is located on the subject Wk when the relative speed between the camera head35and the subject Wk is equal to 0) is what is called a cycloid curve. The camera head35becomes parallel with the subject Wk on the rail80(the relative speed between them becomes approximately equal to 0) at time t0when the camera head35is located at the lowest position of its locus. The camera head35transmits, to the camera control unit50, images from an image taken at time t0or a time immediately before time t0when imaging is started to an image taken at time t2.

At time t0, the camera head35is in a state that its speed relative to the subject Wk is equal to 0. The camera unit30transmits an image of the subject Wk taken at time t0to the camera control unit50. At this time point, the position Oj on the subject Wk is located at the center of an angle of view Ag0. At time t1, the camera head35is in a state that its speed relative to the subject Wk is approximately equal to 0. The camera unit30transmits an image of the subject Wk taken at time t1to the camera control unit50. At this time point, the position Oj on the subject Wk is located at the center of an angle of view Ag1. At time t2, the camera head35is in a state that its speed relative to the subject Wk is approximately equal to 0. The camera unit30transmits an image of the subject Wk taken at time t2to the camera control unit50. At this time point, the position Oj on the subject Wk is located at the center of an angle of view Ag2. After time t2, the transmission of an image of the subject Wk is not transmitted.

As described above, the camera head35which is incorporated in the inspection cart10starts imaging at time t0and finishes the imaging at time t2. The camera head35moves by a distance ΔL in the direction MV1from time t0to time t2. During that time, the position Oj where the camera head35is focused (i.e., the position on the subject Wk in the angle of view of the imaging by the camera head35) does not vary irrespective of the movement distance ΔL of the camera head35, that is, the position Oj which is located in the angles of view corresponding to images taken at times t0, t1, and t2does not vary. The relative speed between the subject Wk and the camera head35is kept approximately equal to 0 from time t0to time t2. Peripheral portions of an image taken by the camera head35are distorted because the movement distance of the camera head35itself is long.

The relative speed between the camera head35and the subject Wk is kept equal to 0 or can be regarded as being kept approximately equal to 0 from time t0to time t2. The time during which the relative speed can be regarded as being kept approximately equal to 0 is a time slot during which images can be taken that allow the camera control unit50to perform image processing on them and image analysis for, for example, detection of an abnormality of the subject Wk. The time from time t0to time t2varies depending on the movement speed of the inspection cart10, the rotation speed of the camera head35, the movement speed of the subject Wk, the imaging distance between the camera head35and the subject Wk, etc. Thus, the time from time t0to time t2may be either set automatically by the camera control unit50on the basis of the above values or set by the user.

FIG. 13is a flowchart showing an example operation procedure of the camera control unit50employed in the first embodiment. The example operation procedure of the camera control unit50shown inFIG. 13is directed to the example of imaging shown inFIG. 11. In the example operation procedure shown inFIG. 13, the subject Wk shown inFIG. 11does not move, that is, its movement speed is equal to 0.

At step S1, the motor control unit51receives and acquires speed information of the inspection cart10from the encoder60. For example, the speed information of the inspection cart10is a movement speed V (km/h) of the inspection cart10.

At step S2, the motor control unit51calculates a rotation speed of the rotary motor37, that is, the number of revolutions per unit time of the drum31, on the basis of the received speed information according to Equation (1). A method for calculating a rotation speed R of the rotary motor37will be described below.

A rotation speed R (rps) of the rotary motor37is calculated according to Equation (1) so that the relative speed between the camera head35which moves at the movement speed V together with the inspection cart10and the subject Wk (or rail80). That is, Equation (1) is an equation for calculating a rotation speed R of the rotary motor37that makes equal to 0 the relative speed between the movement speed (in the X direction) of the surface of the subject Wk to be captured by the camera head35and the movement speed of the camera head35of the inspection cart10at a position where the subject Wk and the camera head35are parallel with and closest to each other. A distance r1(mm) between the camera head35and the subject Wk and a radius r2(mm) of rotation of the camera head35(i.e., the radius of the drum31,31A) may be set by the user in advance.

Using Equation (1), a rotation speed R (rps) of the camera head35shown inFIG. 11can be calculated to be 52 (rps) when, for example, V=70 km/h (19.4 m/s), r1=30 mm, and r2=30 mm. The movement sped of the subject Wk shown inFIG. 11is equal to 0. Thus, where the subject Wk is moved, it is necessary to calculate a rotation speed R (rps) of the rotary motor37further on the basis of a movement direction of the subject Wk, a movement direction of the inspection cart10, and a rotation direction of the camera head35.

At step S3, the motor control unit51generates a control signal to be used for rotating the rotary motor37on the basis of the calculated rotation speed R and transmits the generated control signal to the rotary motor37. The rotary motor37is driven rotationally at the rotation speed R on the basis of the received control signal.

At step S4, the camera control unit52detects, as an exposure start position (exposure start timing), timing at which the relative speed between the camera head35and the subject Wk becomes equal to 0, that is, a position where the camera head35and the subject Wk becomes parallel with each other. Although the term “exposure start position” is used above, it is noted that the imaging element42continues to receive light coming from the subject Wk (optical image) and output an image signal after an inspection start manipulation was made by the user.

Upon detecting an exposure start position at step S4, at step S5the camera control unit52receives an image signal that is transmitted from the imaging element42.

At step S6, the camera control unit50judges whether the inspection cart10has completed a prescribed imaging process that was set by the user. For example, the camera control unit50may finish the imaging either when the inspection cart10has passed an inspection interval set by the user or when an inspection finishing manipulation is made by the user.

If judging that the imaging has not been completed yet (S6: no), the camera control unit50returns to step S1.

On the other hand, if judging that the imaging has been completed (S6: yes), the camera control unit50finishes the inspection process.

As described above, while the inspection cart10employed in the first embodiment runs along the rail80, the camera head35which is disposed in the circumferential surface of the rotating drum31captures the rail80and the subject Wk on the rail80continuously at an imaging position where the camera head35is approximately parallel with the rail80or the subject Wk on the rail80. That is, timing at which the imaging element42starts to be exposed to light (in other words, timing at which the imaging element42starts transmitting data of an image taken to the camera control unit50) is timing at which the relative speed between the movement speed of the subject Wk to be captured by the camera head35and that of the camera head35becomes equal to 0. Since in this state the rail80or the subject Wk on the rail80is stopped relative to the camera head35, a blur of the rail80or the subject Wk on the rail80existing in an image taken by the imaging element42can be made small. As a result, the camera head35can produce a clear image of the rail80or the subject Wk even if the inspection cart10is moving along the rail80at high speed.

Thus, the camera control unit50can detect (make a judgment about) an abnormality (e.g., a scratch, a deteriorated portion, or a damaged portion formed on its surface) of the rail80or the subject Wk in a shorter time on the basis of data of images taken.

Although in the above-described manufacturing system according to the embodiment the camera control unit50has functions of an image processing device, an image processing device may be provided separately from the camera control unit50. In this case, the image processing device performs analysis about presence/absence of an abnormality (e.g., a scratch, a deteriorated portion, or a damaged portion formed on its surface) of the rail80or the subject Wk by doing image analysis on data of images taken that are received from the camera control unit50and outputs an analysis result to a monitor, an alarm lamp, or the like.

First Modification of First Embodiment

The manufacturing system according to the first embodiment is such that the inspection cart10captures a subject Wk while the inspection cart10is moving. A manufacturing system100A according to a first modification of the first embodiment will be described below in which a camera unit30A captures each of plural subjects Wk that are moving. In the first modification of the first embodiment, the same constituent elements as in the first embodiment will be given the same reference symbols and will not be described in detail.

FIG. 14is a rough view of an example manufacturing system1004that includes a camera unit30A according to the first modification of the first embodiment. In the manufacturing system100A according to the first modification of the first embodiment, the camera unit30A that is installed fixedly captures subjects Wk moving at a constant speed. The subjects Wk may be moved either being conveyed by a conveying machine such as a belt conveyor110(seeFIG. 14) or being driven by moving means provided in themselves. The manufacturing system100A is configured so as to include the camera unit30A and a camera control unit50A. The camera head35is configured similarly to the camera unit30employed in the first embodiment and is disposed in the circumferential surface of a drum31which is rotated.

The camera unit30A according to the first modification of the first embodiment captures each of the plural subjects Wk being conveyed by a belt conveyor110. Like the camera unit30or30A according to the first embodiment, the camera unit30A captures each subject Wk with such timing that the relative speed between the camera head35and the subject Wk becomes equal to 0 (in other words, the camera head35and the subject Wk become approximately parallel with each other).

Imaging targets of the camera unit30A according to the first modification of the first embodiment are not limited to plural subjects Wk that are conveyed at a constant speed so as to be arranged at the same interval as shown inFIG. 14. Where the plural subjects Wk are neither arranged at the same interval nor conveyed at a constant speed, the camera control unit50A may be configured so as to be able to capture the subjects Wk by calculating a movement speed of each subject Wk on the basis of a variation of the position of the subject Wk detected by a Hall element (not shown) or a variation of the position of the subject Wk existing in at least two images (frames) taken immediately before and rotating the rotary motor37according to the calculated movement speed.

FIG. 15is a block diagram showing an example internal configuration of the manufacturing system100A according to the first modification of the first embodiment. The manufacturing system100A is configured so as to include the camera unit30A and a camera control unit50A.

The camera unit30A is configured so as to include a work speed detection sensor45in addition to the imaging lens41, the imaging element42, the rotary motor37, and the power supply unit40which were described in the first embodiment. The imaging lens41, the imaging element42, the rotary motor37, and the power supply unit40will not be described in detail because they have the same functions and operate in the same manners as in the first embodiment.

The work speed detection sensor45detects a movement speed of each of the subjects (works) Wk being conveyed by the belt conveyor110. The work speed detection sensor45is, for example, a Hall element, which detects a position of each of the subjects Wk on the basis of a magnetic field variation caused by a magnet attached to the subject Wk. The work speed detection sensor45detects a movement speed of each of the subjects Wk on the basis of detected positions of the respective subjects Wk.

Alternatively, the work speed detection sensor45may be a fixed-point camera. The fixed-point camera detects a movement speed of each of the subjects (works) Wk by measuring a position variation of the subject Wk existing in at least two images (frames) taken by performing image analysis on the at least two images. In this case, a movement speed of each of the subjects Wk can be detected easily without using additional electronic device such as a Hall element.

The work speed detection sensor45transmits the detected movement speed information of each of the subjects (works) Wk to the camera control unit50A. The camera control unit50A may calculate a rotation speed R of the rotary motor37adaptively on the basis of the received movement speed of each subject Wk. The camera control unit50A transmits the calculated rotation speed R to the camera unit30A. As a result, the camera unit30A can change the rotation speed R when necessary according to a movement speed of a subject Wk and hence can capture the subject Wk in a state that the relative speed between the camera head35and the subject Wk is made approximately equal to 0.

Imaging targets of the camera unit30A according to the first modification of the first embodiment are not limited to plural subjects Wk that are conveyed being arranged at the same interval as shown inFIG. 14. Thus, the camera unit30A may have such an angle of view that plural subjects Wk exist in one image taken.

The camera control unit504is configured so as to include a motor control unit51A, a camera control unit52, an LED control unit53, and a power source unit54. The motor control unit51A calculates a rotation speed R of the rotary motor37on the basis of received speed information of a subject Wk and generates a control signal for controlling the rotary motor37.

The camera control unit50A may have an external input interface and receive a conveyance speed of the belt conveyor110via the external input interface. In this case, the camera control unit50A may infer that a movement speed of the subjects Wk is equal to that of the belt conveyor110: the work speed detection sensor45can be omitted.

An operation procedure of the manufacturing system100A shown inFIGS. 14 and 15will be described with reference toFIG. 16.FIG. 16is a flowchart showing an example operation procedure of the manufacturing system100A according to the first modification of the first embodiment.

At step S1A, the motor control unit51A receives and acquires speed information of a subject Wk from the work speed detection sensor45. For example, the speed information may be a conveyance speed that is set for the belt conveyor110.

At step S2A, the motor control unit51A calculates a rotation speed R of the rotary motor37, that is, the number of revolutions per unit time of the drum31, on the basis of the received speed information according to Equation (2). The movement speed VA(m/s) in Equation (2) is the movement speed of the subject Wk.

Equation (2) is an equation for calculating a rotation speed R of the rotary motor37that makes equal to 0 the relative speed between the movement speed (in the X direction) VAof the surface of the subject Wk to be captured by the camera head35and the movement speed of the camera head35at a position where the camera head35is closest to the moving subject Wk (i.e., a position where the camera head35and the subject Wk are parallel with each other).

At step S3A, the motor control unit51A generates a control signal to be used for rotating the rotary motor37on the basis of the calculated rotation speed R and transmits the generated control signal to the rotary motor37. The rotary motor37is driven rotationally at the rotation speed R on the basis of the received control signal.

Steps S4to S6will not be described in detail because they are the same as in the operation procedure of the manufacturing system according to the first embodiment.

As described above, in the manufacturing system100A according to the first modification of the first embodiment, plural subjects Wk being conveyed by the belt conveyor110are captured by the camera head35continuously. Timing at which the imaging element42starts to be exposed to light (in other words, timing at which data of an image taken is transmitted to the camera control unit50A) is timing at which the relative speed between the movement speed of each subject Wk to be captured by the camera head35and that of the camera head35of the inspection cart10becomes equal to 0. Since in this state the subject Wk on the belt conveyor110is stopped relative to the camera head35, a blur of the subject Wk existing in an image taken by the imaging element42can be made small. As a result, the camera head35can produce a clear image of the subject Wk even if the belt conveyor110is conveying the subject Wk at a conveyance speed that is higher than a conventional conveyance speed.

Thus, the camera control unit50A can detect (make a judgment about) an abnormality (e.g., a scratch, a deteriorated portion, or a damaged portion formed on its surface) of each subject Wk in a shorter time on the basis of data of images taken.

Second Embodiment

The camera unit30according to the first embodiment has one camera head35which is disposed in the circumferential surface of the drum31. Provided with only one camera head35, the camera unit30according to the first embodiment is restricted in the imaging-possible angle of view and the imaging timing. Since it is preferable that a subject Wk be captured so as to included in the angle of view in its entirety, it is difficult to shorten the imaging distance between the camera head35and the subject Wk. In the camera unit30according to the first embodiment, the resolution of an image taken is low because it employs the same kind of illumination (illumination unit33) as in conventional cases to prevent its size increase. Furthermore, in the camera unit30according to the first embodiment, since the camera head35performs imaging while rotating, peripheral portions of an image taken may be distorted more than its central portion.

In view of the above, in a camera unit309according to a second embodiment, plural camera heads are provided in the peripheral surface of a drum31A. In the camera unit30B according to the second embodiment, since the number of camera heads is increased, the number of timings at which the relative speed between a camera head and a subject Wk is made equal to 0 (i.e., a camera head and a subject Wk become parallel with each other) can be increased. In this manner, in the camera unit30B according to the second embodiment, the number of images taken to be transmitted to the camera control unit50for each subject Wk can be increased. Furthermore, since the increase in the number of images taken makes it unnecessary to capture each subject Wk in such a manner that it is included in an angle of view, it becomes possible to capture each subject Wk from a position closer to it. Still further, in the camera control unit50according to the second embodiment, since the resolution of an image taken of one subject Wk can be increased by adding its plural images pixel by pixel, data of an image taken can be generated in which peripheral portions are reduced in distortion.

The camera unit30B according to the second embodiment can be applied to both of the case that the camera unit30B performs imaging while being moved by the inspection cart10or the like (first embodiment) and the case that the camera unit30B is fixed and subjects Wk are moved (first modification of the first embodiment).

In the following description of the second embodiment, constituent elements having the same ones in the first embodiment or the first modification of the first embodiment will be given the same reference symbols as the latter and will not be described in detail.

The drum31A employed in the second embodiment will be described below with reference toFIGS. 17 and 18.FIG. 17is a perspective view showing an example appearance of the drum31A employed in the second embodiment.FIG. 18is a sectional view showing an example arrangement of four camera heads35A,35B,35C, and35D provided in the drum31A. Although in this example the four camera heads35A,35B,35C, and35D are disposed in the circumferential surface of the drum31A, it goes without saying that the number of camera heads is not limited to four and may be two or larger than two.

Four openings are formed in the circumferential surface of the drum31A at intervals of 90°. The four openings are openings that allow the imaging elements42of the four camera heads35A,35B,35C, and35D to capture subjects Wk, respectively. Each of the four openings may be fitted with a transparent member. Each of the four camera heads35A,35B,35C, and35D has the same configuration as the camera head35employed in the first embodiment and the first modification of the first embodiment.

FIG. 19is a diagram showing an example of how the four camera heads35A,35B,35C, and35D perform imaging. In the camera unit30B shown inFIG. 19, each of the four camera heads35A,35B,35C, and35D captures subjects TgA and TgB as the drum314is moved in a direction MV2while being rotated in a direction MM2.

The four camera heads35A,35B,35C, and35D have respective angles of view Ag21, Ag22, Ag23, and Ag24. The four camera heads35A,35B,35C, and35D capture the subjects TgA and TgB in such a manner their angles of view Ag21, Ag22, Ag23, and Ag24overlap with each other and each of the subjects TgA and TgB is captured by plural ones of the camera heads35A,35B,35C, and35D. In the camera unit30B shown inFIG. 19, the angle of view Ag21of the camera head354and the angle of view Ag22of the camera head35B cover the subject TgA. The angle of view Ag22of the camera head35B, the angle of view Ag23of the camera head35C, and the angle of view Ag24of the camera head35D cover the subject TgB.

With the above measure, in the camera unit30B, even if the angle of view of a camera head facing the subject side (e.g., the angle of view Ag21of the camera head35A) does not fully cover the subject TgA, the angle of view of the camera head that faces the subject side next (e.g., the angle of view Ag22of the camera head35B) also covers the subject TgA. In this manner, in the camera unit30B, each of the plural subjects TgA and TgB can be captured in such a manner that corresponding ones of the plural camera heads35A to35D are brought close to it. The distance from the camera head35to the subject (distance to subject) is set at 40 mm, for example. The camera control unit50can perform pixel-by-pixel addition in peripheral portions of plural images taken of one subject because the peripheral portions can overlap with each other. As a result, the camera control unit50can increase the resolution of peripheral portions of each image taken.

FIG. 20is a diagram showing an example of imaging by a single camera head35. The camera unit30shown inFIG. 20has one camera head35like the camera unit30according to the first embodiment does. In the camera unit30shown inFIG. 20, the camera head35captures each of subjects TgA and TgB as the drum31is moved in a direction MV2while being rotated in a direction MM2.

As shown inFIG. 20, the camera unit30having the single camera head35should preferably capture subjects TgA and TgB in such a manner that its angle of view covers each of the subjects TgA and TgB fully, even preferably in such a manner that each of the subjects TgA and TgB is located at a central portion of the angle of view. In this case, the camera head35is disposed at a position that is far from the subjects Tg and captures each of the subjects TgA and TgB in such a manner that it is covered by the angle of view. For example, to allow the camera head35to capture each of the subjects TgA and TgB in the same manner as in the case where the four camera heads35A to35D are provided, the distance from the camera head35to each of the subjects TgA and TgB (distance to subject) needs to be set two times as long as a distance of the case that the four camera heads35A to35D are provided. More specifically, where the camera head35performs high-speed imaging under conditions that the frame rate is 120 (fps), the diagonal angle of view is 120°, and the movement speed is 100 km/h, an imaging interval to the next frame is equal to 277.8 mm. Thus, a distance of about 80 mm is necessary between the camera head35and each of the subjects TgA and TgB.

On the other hand, in the camera unit30B according to the second embodiment, the four camera heads35A to35D are disposed in the peripheral surface of the drum31A at intervals of 90°. Thus, each of the four camera heads35A to35D can capture each subject Tg from a closer position. As a result, in performing high-speed imaging on each subject Tg, the resolution of an image taken by the camera unit30B according to the second embodiment can be made higher. Furthermore, in the camera unit30B according to the second embodiment, imaging is performed so that peripheral portions of images taken overlap with each other and pixel-by-pixel addition is performed in the overlap, whereby distortion of the images can be suppressed and the peripheral portions of the images can be increased in resolution.

First Modification of Second Embodiment

FIG. 21is a diagram showing an example internal configuration of a camera unit30C according to a first modification of the second embodiment. In the camera unit30C, four openings are formed in the peripheral surface of a drum31B. Each of the four openings is formed at a position that is deviated by a distance B from one of two lines (indicated by chain lines inFIG. 21) that divide the camera unit30C into four equal parts. Four camera heads35E,35F,35G, and35H are disposed like the blades of a windmill at positions that are deviated by a distance B from the two lines that divide the camera unit30C into four equal parts. With this structure, the four camera heads35E to35H and four imaging elements42E,42F,42G, and42H can be located at positions that are closer to the rotation axis of the camera unit30C than in the camera unit30B shown inFIG. 18having the four camera heads35A to35D.

As a result, the size (diameter) of the camera unit30C according to the first modification of the second embodiment can be made smaller. Furthermore, in the camera unit30C, since the four camera heads35E to35H are deviated by the distance B from the above two lines passing through the rotation axis, the degree of distortion in peripheral portions of each image taken can be lowered (refer to paragraph 0053).

Second Modification of Second Embodiment

FIG. 22is a diagram showing an example internal configuration of a camera unit30D according to a second modification of the second embodiment. In the camera unit30D, four openings are formed in the peripheral surface of a drum31C at intervals of an angle 90°. Two camera heads35I and35K are disposed in such a manner that they are opposed to each other and their center lines coincide with one of two lines that divide the camera unit30D into four equal parts. Likewise, two imaging units42I and42K are disposed in such a manner that they are opposed to each other and their center lines coincide with the one of the two lines that divide the camera unit30D into four equal parts. A camera head35J and an imaging element42J are arranged parallel with and directed oppositely to the camera head35K and the imaging element42K. A camera head35L and an imaging element42L are arranged parallel with and directed oppositely to the camera head35I and the imaging element42I.

The camera head35J has an imaging lens41J for focusing light reflected by a mirror46J which reflects light coming from an opening44J by 90° and the imaging element42J for converting an optical image formed by the imaging lens41J into an image signal. Likewise, the camera head35L has an imaging lens41L for focusing light reflected by a mirror46L which reflects light coming from an opening44L by 90° and the imaging element42L for converting an optical image formed by the imaging lens41L into an image signal. Each of the four openings may be fitted with a transparent member.

In the camera unit30D according to the second modification of the second embodiment, the optical axes of the four imaging elements42I to42L are arranged parallel with each other because of the intervention of the two mirrors46J and46L. With this measure, in camera unit30D according to the second modification of the second embodiment, the four camera heads35I to35L can be disposed closer to the rotation axis of the camera unit30D than the four camera heads35A to35D of the camera unit30B shown inFIG. 18are to its rotation axis.

Where a camera unit is equipped with mirrors, an improvement may be made so that the number of images is increased that are taken with a subject located at the center of the angle of view of imaging by rotating each mirror by a very small angle according to a rotation speed of the camera unit and thereby changing the center line of imaging in which the subject is located right in front of the camera head. Each mirror provided in a camera unit is not limited to a planar mirror; for example, a prism may be provided instead of the planar mirror to enable selection of an input wavelength.

As such, the size (diameter) of the camera unit30D according to the second modification of the second embodiment can be made smaller.

Third Modification of Second Embodiment

FIG. 23is a diagram showing an example internal configuration of a camera unit30E according to a third modification of the second embodiment. The camera unit30E is equipped with two drums31D1and31D2and is thus about two times as thick as in the case where the drum31or31B is employed.

In the drum31D1, four camera heads35M,35N, . . . are formed in its circumferential surface at the same intervals. In the drum31D2, four camera heads35O,35P, are formed in its circumferential surface at the same intervals. The four camera heads35M,35N, . . . and the four camera heads35O,35P, . . . are deviated so as not to be located at the same positions in the circumferential direction of the drums31D1and31D2(i.e., in the rotation direction of the camera unit30E).

Although in the example shown inFIG. 23the four camera heads35M,35N, . . . are deviated from the four respective camera heads35O,35P, by 45° (staggered arrangement), the manner of deviation is not limited to this; the camera heads35M,35N, . . . may be deviated from the respective camera heads35O,35P, . . . by 20° or 30°. The number of camera heads provided in each of the drums31D1and31D2is not limited to four and may be two, for example. Furthermore, the numbers of camera heads provided in the respective drums31D1and31D2need not always be identical.

As described above, in the camera unit30E according to the third modification of the second embodiment, since the camera heads are arranged in two levels, the number of camera heads can be increased without increasing the diameter of the camera unit30E. In the camera unit30E according to the third modification of the second embodiment, the degree of freedom of arrangement of camera units can be increased. Thus, the camera unit30E can capture subjects reliably by virtue of an increased number of camera heads even in the case where the camera heads capture the subjects while the camera unit30E is moving or rotating at high speed. Furthermore, in the camera unit30E, the number of images taken by plural respective camera heads can be increased and, at the same time, the number of overlaps between the ranges of angles of view can be increased. As a result, the camera control unit50can increase the resolution of peripheral portions of each image corresponding to peripheral portions of the range of each angle of view by performing addition on a pixel-by-pixel basis.

Fourth Modification of Second Embodiment

FIG. 24is a diagram showing an example internal configuration of a camera unit30F according to a fourth modification of the second embodiment. As in the camera unit30E according to the third modification of the second embodiment, a drum31E of the camera unit30F according to the fourth modification of the second embodiment is about two times as thick as the drums31and31B. In the camera unit30F, four camera heads35Q,35R, . . . are formed in a lower part of the circumferential surface of the drum31E and four camera heads35S,35T, . . . are formed in an upper part of the circumferential surface of the drum31E. The four camera heads35Q,35R, . . . and the four camera heads35S,35T, . . . are formed at the same positions in the circumferential direction (i.e., the rotation direction of the camera unit30F), respectively.

As described above, in the camera unit30F according to the fourth modification of the second embodiment, since the camera heads are arranged in two levels, the number of camera heads can be increased without increasing the diameter of the camera unit30F. In the camera unit30F according to the fourth modification of the second embodiment, the degree of freedom of arrangement of camera units can be increased. Thus, the camera unit30F can capture subjects reliably by virtue of an increased number of camera heads even in the case where the camera heads capture the subjects while the camera unit30F is moving or rotating at high speed. Furthermore, in the camera unit30F, the number of images taken by plural respective camera heads can be increased and, at the same time, the number of overlaps between the ranges of angles of view can be increased. As a result, the camera control unit50can increase the resolution of peripheral portions of each image corresponding to peripheral portions of the range of each angle of view by performing addition on a pixel-by-pixel basis.

Third Embodiment

In the first and second embodiments, the camera heads are disposed in the peripheral surface of the drum. In a third embodiment, a camera head is disposed in a side surface of the drum. The third embodiment is directed to a case that the camera head captures a subject while being moved. In the following description of the camera device according to the third embodiment, constituent elements having the same ones in the first or second embodiment will be given the same reference symbols as the latter and will not be described in detail.

FIG. 25is a perspective view showing an example appearance of the camera unit30G according to the third embodiment. In the camera unit30G according to the third embodiment, a camera head35U is disposed in an opening formed in a side surface of a ring-shaped drum31G. The optical axis of the camera head35U is parallel with the rotation axis of the drum31G. The camera head35U is rotated in a direction MM3around the rotation axis.

FIG. 26is a view showing an example manner of imaging by the camera unit30G. A subject TgC is suspended on a rail180. The camera unit30G is disposed under the rail180and captures the subject TgC from under the subject TgC as the camera unit30G is moved at a prescribed speed in a direction MV3alongside the rail180while being rotated in the direction MM3of the drum31G. The camera head35U is rotated around the rotation axis of the drum31G. Although the camera unit30G shown inFIG. 26is moved by an inspection cart10, the inspection cart10is omitted inFIG. 26to simplify the description. Where the subject TgC is moved, it may be conveyed by the rail180serving as part of a conveying machine.

The positional relationship between the camera unit30G and the subject TgC may be opposite to that shown inFIG. 26. That is, the camera unit30G may be suspended on the rail180and capture the subject TgC disposed under the camera unit30G.

FIG. 27is a diagram showing an example of how the camera unit30G according to the third embodiment captures the subject TgC. The drum31G shown inFIG. 27is moved in the direction MV3. The camera unit30G according to the third embodiment transmits, to the camera control unit50, an image of the subject TgC that was taken while being moved in the X direction by a movement distance ΔL1.

The camera head35U employed in the third embodiment is moved while being rotated so as to form, with respect to the subject TgC, a trace that is shaped like a cycloid curve. That is, the subject TgC is captured so that its locus in plural images taken with respective view ranges likewise becomes a cycloid curve.FIG. 27shows a view range Ag31of the camera head35U and a corresponding position of the subject TgC at timing of a start of exposure as well as a view range Ag32of the camera head35U and the corresponding position of the subject TgC at timing of an end of the exposure.

At the timing of the start of exposure, the relative speed between the X component of the rotation speed of the camera head35U and the movement speed of the camera head35U is made equal to zero. The time during which the relative speed between the camera head35U and the subject TgC is kept equal to 0 is long because the camera head35U is disposed so that its optical axis is parallel with the rotation axis of the drum31G and hence the position variation of the subject TgC moving relative to the view range is made smaller.

As a result, the camera unit30G according to the third embodiment can capture the subject TgC for a longer time. That is, the camera control unit50employed in the third embodiment can receive more images for the single subject TgC and the variation of the position of the single subject TgC with respect to the center of a view range is made smaller. Thus, the camera control unit50can generate data of clearer images taken. Furthermore, capable of receiving many images taken that are suitable for addition for image quality improvement, the resolution corresponding to a peripheral portion of a view range can be made higher.

In a fourth embodiment, a camera head35W is disposed in the circumferential surface of a drum31H and performs imaging being always directed to one direction (i.e., the direction of a subject TgD) while the drum31H is moved (rotation is caused in the drum31H). In the following description of a camera unit34H according to the fourth embodiment, constituent elements having the same ones in the control unit30or30A according to the first embodiment will be given the same reference symbols as the latter and will not be described in detail.

FIG. 28is a perspective view showing an example appearance of the camera unit34H according to the fourth embodiment. The camera unit34H has a drum31H which is thicker than the drum31employed in the first embodiment. The circumferential surface of the drum31H is formed with an opening that allows a camera head35W to capture a subject TgD.

FIG. 29is a perspective view showing an example internal mechanism of the drum31H.FIG. 30is a diagram showing an example operation of a first gear131and a second gear132. The drum31H is equipped with a gear mechanism130which has the first gear131and the second gear132.

The first gear131is supported pivotally by a rotary motor37, for example, and is driven rotationally in a direction MM4aat a rotation speed R. The first gear131is in mesh with the second gear132with a speed reduction ratio 1 and transmits rotational power to the second gear132.

The second gear132supports the camera head35W pivotally. The second gear132is rotated in a direction MM4bby the rotational power transmitted from the first gear131(speed reduction ratio: 1). That is, the second gear132is in mesh with the first gear131and rotates on its axis while circling around the first gear131. Thus, the camera head35W which is supported by the second gear132pivotally can perform imaging in such a manner as to be always directed in the same direction (−Z direction inFIG. 30).

FIG. 31is a diagram showing an example of how a subject TgD is captured by the camera unit30H according to the fourth embodiment. As described above with reference toFIGS. 29 and 30, the camera head35W and its angle of view Ag40are always directed toward the subject TgD (i.e., in the −Z direction).

The camera head35W according to the fourth embodiment is controlled by the camera control unit50in such a manner that rotation is caused in the drum31H at a rotation speed that makes approximately equal to 0 the relative speed between a movement speed (in the X direction) of the subject TgD and a movement speed of the camera head35W at a position where the distance between the camera head35W and the subject TgD is smallest. With this measure, the camera head35W can capture the subject TgD by starting exposure at such timing that the distance to the subject TgD becomes smallest (i.e., the imaging distance to the subject TgD becomes smallest).

FIG. 32is another diagram showing an example of how the subject TgD is captured by the camera unit30H according to the fourth embodiment. The camera unit30H is moved in a direction MV4. The camera head35W employed in the fourth embodiment starts exposure from a position where the distance between the camera head35W and the subject TgD is smallest (in other words, starts transmission of an image taken to the camera control unit50). An angle of view Ag42of the camera head35W at timing when the relative speed between the camera head35W and the subject TgD can be regarded as being equal to 0 is made larger than an angle of view Ag41at timing when the relative speed between the camera head35W and the subject TgD is equal to 0 according to a movement distance of the camera head35W in the Z direction per an imaging time of the camera head35W.

As described above, in the camera unit30H according to the fourth embodiment, since the camera head35W performs imaging being always directed toward the subject TgD, the variation, from the center of the angle of view, of the position of the subject TgD in each of plural images taken that are transmitted to the camera control unit50is much smaller than in the other embodiments. As a result, in the camera unit30H according to the fourth embodiment, the deviation of the imaging position of the subject TgD of each of plural images taken that are transmitted to the camera control unit50can be made small and data of images taken that are high in resolution in peripheral portions of an angle of view can be generated by performing pixel-by-pixel addition using many images. Furthermore, by performing pixel-by-pixel addition, the camera control unit50can suppress distortion of an image due to a difference in distance between a peripheral portion of a subject-side view range and a peripheral portion of a camera-side view range that occurs when the subject TgD is captured obliquely.

Fifth Embodiment

In the above-described camera units according to the first to fourth embodiments, a subject can be captured by making the relative speed between the camera head and a subject approximately equal to 0 by rotating the drum (or causing rotation in the drum). In a camera unit according to a fifth embodiment to be described below, a piston mechanism is provided and a subject is captured in such a manner that the relative speed between the camera head and the subject is made approximately equal to 0 by driving the piston mechanism.

In the following description of the camera unit according to the fifth embodiment, constituent elements having the same ones in the third embodiment will be given the same reference symbols as the latter and will not be described in detail. The camera unit30J according to the fifth embodiment can be applied to not only a case of a moving subject TgE but also a case that the camera unit30J performs imaging while being moved.

The configuration and a moving mechanism of the camera unit30J according to the fifth embodiment with reference toFIGS. 33 to 36.FIG. 33is a perspective view showing an example appearance of the camera unit30J according to the fifth embodiment.FIG. 34is a perspective view showing an example appearance of the camera unit30J as viewed from below inFIG. 33.FIG. 35is a front view showing an example drive mechanism of the camera unit30J as viewed from an arrowed line H-H inFIG. 33.FIG. 36is a perspective view showing the example drive mechanism of the camera unit30J as viewed from the arrowed line H-H inFIG. 33.

The camera unit30J is configured so as to have two guide plates151and161, a drive shaft152, two cams153and163, two connecting rods154, and164, two bearings155zand165z, two sensors158and168, and two camera heads35Z and35V. In the camera unit30J, rotational drive power of a rotary motor37is transmitted to the two cams153and163by the drive shaft152to rotate them. Rotational drive power of the two cams153and163is transmitted to the two connecting rods154, and164, whereby the two camera heads35Z and35V which are provided on the side of one end portions of the connecting rods154, and164are reciprocated, respectively. That is, the camera unit30J is equipped with a piston mechanism150for reciprocating the camera head35Z and a piston mechanism160for reciprocating the camera head35V. The two piston mechanisms150and160are disposed adjacent to each other.

The piston mechanism150has the guide plate151which is approximately shaped like an ellipse. A hole151zis formed through the guide plate151so as to extend in its longitudinal direction. The piston mechanism160has the guide plate161which is approximately shaped like an ellipse. A hole161zis formed through the guide plate161so as to extend in its longitudinal direction.

Two circular-disc-shaped cams153and163facing the confronting surfaces of the guide plates151and161are supported rotatably by the guide plates151and161, respectively.

Rotational drive power of a rotary motor (not shown) is transmitted to the drive shaft152, whereby the two cams153and163which are connected to the drive shaft152are rotated. The cam153is provided with, at one point in the circumferential direction, an engagement portion153zthat is engaged with the other end portion of the connecting rod154. The cam163is provided with, at one point in the circumferential direction, an engagement portion163zthat is engaged with the other end portion of the connecting rod164.

The one end portion of the connecting rod154is provided with a head portion155, and the one end portion of the connecting rod164is provided with a head portion165.

The head portion155has the bearing155zthat is inserted slidably in the longitudinal hole151zof the guide plate151. Likewise, the head portion165has the bearing165zthat is inserted slidably in the longitudinal hole161zof the guide plate161. The camera heads35Z and35V are attached to the respective head portions155and165.

In the piston mechanism150, when the drive shaft152is rotated being driven rotationally by the rotary motor, rotational drive power of the rotary motor is transmitted to the cam153, whereby the cam153is rotated. The connecting rod154which is connected to the engagement portion153zof the cam153advances and retreats in the X direction as the cam153is rotated. The camera head35Z which is attached to the head portion155which is moved in link with the connecting rod154advances and retreats in the X direction as the cam153is rotated. The sensor158capable of detecting an imaging start position (i.e., exposure start timing) is provided at the cam-153-side end of the longitudinal hole151z. A Hall element or a proximity switch, for example, is used as the sensor158and detects approach of, for example, a magnet attached to the end portion of the connecting rod154.

Likewise, the piston mechanism160, when the drive shaft152is rotated being driven rotationally by the rotary motor, rotational drive power of the rotary motor is transmitted to the cam163, whereby the cam163is rotated. The connecting rod164which is connected to the engagement portion163zof the cam163advances and retreats in the X direction as the cam163is rotated. The camera head35V which is attached to the head portion165which is moved in link with the connecting rod164advances and retreats in the X direction as the cam163is rotated. The sensor168capable of detecting an imaging start position (i.e., exposure start timing) is provided at the cam-163-side end of the longitudinal hole161z. A Hall element or a proximity switch, for example, is used as the sensor168and detects approach of, for example, a magnet attached to the end portion of the connecting rod164.

FIG. 37is a diagram for description of an example imaging operation of the camera unit30J according to the fifth embodiment. In the camera unit30J according to the fifth embodiment, the two piston mechanisms150and160cause the camera heads35Z and35V to advance and retreat alternately in the X direction which is the same as a movement direction MVS of subjects TgF. In the camera unit30J according to the fifth embodiment shown inFIG. 37, the camera head35Z captures plural subjects TgF. InFIG. 37, the two guide plates151and161are omitted to simplify the description.

The camera head35Z starts exposure (i.e., starts transmitting an image taken to the camera control unit50) as soon as the rear end of the connecting rod154is detected by the sensor158(i.e., an imaging start position is detected). Timing at which the relative speed between the camera head35Z and a subject TgF becomes 0 is timing at which the distance between camera head35Z and the subject TgF becomes smallest. When the connecting rod154reaches the end that is opposite to the sensor158, the camera head35Z stops the imaging (i.e., transmission of an image taken to the camera control unit50is stopped).

At timing when the camera head35Z stops imaging, an imaging start position is detected is detected by the sensor168and the camera head35V starts exposure (i.e., starts transmitting an image taken to the camera control unit50). Timing at which the relative speed between the camera head35V and the next subject (not shown) becomes approximately equal to 0 is timing at which the distance between camera head35V and the next subject becomes smallest. When the connecting rod164reaches the end that is opposite to the sensor168, the camera head35V stops the imaging (i.e., transmission of an image taken to the camera control unit50is stopped).

Where the camera unit30J moves in the direction MV5and plural subjects are stopped, each of the two camera heads35Z and35V captures a subject while moving in the −X direction. In this case, the relative speed between each of the two camera heads35Z and35V and a subject becomes approximately equal to 0 at timing when the distance between the camera head35Z or35V and the subject becomes smallest.

The same operation as described above is performed repeatedly. In the camera unit30J according to the fifth embodiment, the relative speed between each of the camera heads35Z and35V and a subject TgF becomes approximately equal to 0 at timing when the two engagement portions153zand163zreach a position P1. At this time, a rotation speed of the rotary motor37is calculated on the basis of a movement speed of the subject TgF, a movement speed of the camera unit30J, and movement speeds of the two camera heads35Z and35V so that the relative speed between each of the camera heads35Z and35V and the subject TgF becomes approximately equal to 0.

In the camera unit30J according to the fifth embodiment, angles of view of the camera heads35Z and35V overlap with each other because the piston mechanisms150and160are adjacent to each other and the camera heads35Z and35V are located close to each other.

FIG. 38is a flowchart showing an example operation procedure of a manufacturing system according to the fifth embodiment. A description will be made with reference toFIG. 18with an assumption that subjects TgF are moving subjects.

At step S1B, the motor control unit51A receives and acquires speed information of subjects TgF from the work speed detection sensor45. Where the camera unit30J is moved, the motor control unit51A receives movement speed information of the camera unit30J.

At step S2B, the motor control unit51A calculates, on the basis of the received speed information of the subjects TgF, a rotation speed R of the rotary motor37for causing the cams153and163to be driven rotationally so that relative speed between each of the two camera heads35Z and35V and a subject TgF becomes equal to 0.

At step S3B, the motor control unit51A generates a control signal to be used for rotating the rotary motor37on the basis of the calculated rotation speed R and transmits the generated control signal to the rotary motor37. The rotary motor37is driven rotationally at the rotation speed R on the basis of the received control signal.

At step S4B, the camera control unit52detects timing when the camera head35Z or35V is to start imaging on the basis of detection information of each of the two sensors158and168.

If at step S4B the camera control unit52detects timing when the camera head35Z is to start imaging on the basis of detection information of each of the two sensors158and168(S4B: camera head1on), at step S5B the camera control unit52starts reception of images taken by the camera head35Z.

If at step S4B the camera control unit52detects timing when the camera head35V is to start imaging on the basis of detection information of each of the two sensors158and168(S4B: camera head2on), at step S6B the camera control unit52starts reception of images taken by the camera head35V.

At step S7B, the camera control unit50A judges whether the camera unit30J has completed a prescribed imaging process that was set by the user. For example, the camera control unit50A may finish the imaging either when an inspection interval set by the user has passed or when an inspection finishing manipulation is made by the user.

If judging that the imaging has not been completed yet (S7B: no), the camera control unit50A returns to step S1B.

On the other hand, if judging that the imaging has been completed (S7B: yes), the camera control unit50A finishes the inspection process.

As described above, the camera unit30J according to the fifth embodiment in which the camera head35Z and the camera head35V advance and retreat alternately, plural subjects TgF can be captured successively. As a result, the camera control unit50A can suppress image blurring in a direction opposite to the movement direction of the subjects TgF.

Although the various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not restricted to those embodiments. It is apparent that those skilled in the art would be able to conceive various changes and modifications without departing from the scope of the claims, and they should naturally be construed as belonging to the technical scope of the disclosure.

For example, although the camera unit30A of the manufacturing system100A according to the first modification of the first embodiment is installed fixedly whereas the plural subjects Wk are conveyed by the belt conveyor110, the camera unit30A may be installed on the inspection vehicle10and capture each of the subjects Wk while moving. As a result, the manufacturing system1004can be increased in imaging speed.

As described above, the camera unit30(camera device) is equipped with the at least one camera head35(imaging unit) which captures the rail80(subject), the rotary motor37(rotary motor) which rotates the camera head35at a prescribed rotation speed a harness43(output unit) which outputs images taken by the camera head35, the drum31(body) which incorporates the camera head35, the rotary motor37, and the harness43. The harness43outputs at least one image, among the images, taken at an imaging position where the camera head35and a surface of the rail80are approximately parallel with each other. With the above configuration, the camera unit30can produce a clear image by imaging the rail80(subject) can acquire a clear image simply in a short time and hence increase the production efficiency.

The camera head35is installed so as to be capable of imaging in a direction that is perpendicular to a rotation axis of the drum31. This makes it possible to produce a clear image by imaging the rail80(subject) consecutively.

The camera head35is installed so as to be capable of imaging in a direction that is parallel with a rotation axis of the drum31. With this measure, the camera head35can capture the subject in such a state that the angle of view deviation from the center in an imaging duration is small, whereby image blurring can be suppressed.

The four camera heads35A,35B,35C, and35D (plural imaging units) are disposed in the same circumferential surface that is perpendicular to the rotation axis of the drum31. With this measure, each camera head35can capture the subject from a position that is close to the subject. Furthermore, the resolution of images taken can be increased when the camera head35captures a subject that is moving at a high speed. Still further, the distortion of each image can be suppressed because peripheral portions of each image are taken so as to overlap with each other, whereby the resolution of overlap portions of each image can be increased.

The camera unit30D is further equipped with the at least one mirror46J and46L and at least one opening44J through which light coming from the imaging position passes to shine on the mirrors46J and46L. Among the four camera heads35I,35J,35K, and35L, each the camera heads35J and35L (at least one imaging unit) captures a subject on the basis of light reflected by the mirror46J or46L. As a result, with the intervention of the mirrors46J and46L, the four imaging elements are arranged so that their optical axes are arranged parallel with each other. Furthermore, the four camera heads35I,35J,35K, and35L are disposed close to each other near the center of the drum31C, In a central portion of the drum31C, a small empty space remains and the two image devices and the two mirror46J or46L are arranged densely. This configuration accelerates miniaturization of the camera unit30D.

The camera unit30H is further equipped with the first gear131which is coupled with the rotary motor37and transmits rotational power of the rotary motor37and the second gear132which is coupled with the first gear131and transmits rotational power from the first gear131to the camera head35W. The camera head35W is rotated via the first gear131and the second gear132so that its imaging direction always coincides with a direction at the imaging position. With this measure, a subject can be captured without blurring of the camera head35W. Furthermore, a subject can be captured from right above from a start to an end of imaging. As a result, the number of images can be increased that can be captured squarely and a high-resolution image can be obtained by pixel-by-pixel addition using many images taken.

The camera unit30J is further equipped with two connecting rods154and164each of which has a camera head35Z or35V on the side of its one end, two cams153and163connected to the other ends of the connecting rods154and164, respectively; and a drive shaft152which is connected to the rotary motor37and transmits rotational power of the rotary motor37to the two cams153and163. The camera heads35Z and35V capture the subject alternately. With this measure, since the two camera heads35Z and35V advance and retreat alternately, one of them is moved in the same direction as a subject is. One of the camera heads35Z and35V can capture a subject at timing when the relative speed between a movement speed of the subject and a movement speed of the one camera head35Z or35V is made equal to 0.

The camera unit30A is further equipped with the subject speed detection sensor45(subject speed detection unit) which detects a movement speed of the work Wk (subject) on the basis of images taken. With this measure, a speed of a work can be detected easily without using an additional electronic component by performing image analysis on the images taken.

The motor control unit51calculates and sets a rotation speed of the rotary motor37that makes a relative speed between the camera head35and the subject located at the imaging position equal to 0. With this measure, the camera head35can capture a subject in a state that the subject is stationary relative to the camera head35. This makes it possible to suppress image blurring in the direction opposite to the moving direction that is prone to occur when the camera head35captures a moving subject.

In the manufacturing system100, the camera unit30(camera) which is installed in an inspection cart10captures a subject such as the rail80. The inspection cart10and the image processing device are connected to each other by a wired or wireless network so as to be able to communicate with each other. The camera unit30transmits at least one image taken at an imaging position where the subject and the camera head35being rotated at a rotation speed R (prescribed rotation speed) of the rotary motor37are approximately parallel with each other. The image processing device analyzes a state of the subject on the basis of the received at least one image and outputs an analysis result. This configuration increases the production efficiency.

The manufacturing system100is equipped with the inspection cart10(conveying device) which moves the camera unit30at a prescribed movement speed. The motor control unit51A calculates and sets, for the rotary motor37, a rotation speed that makes a relative speed between the camera head135and the subject located at the imaging position equal to 0 on the basis of the movement speed of the inspection cart10. With this measure, the camera head135can capture a subject in a state that the subject is stationary relative to the camera head35. This makes it possible to suppress image blurring in the direction opposite to the moving direction that is prone to occur when the camera head35captures a moving subject.

Although the various embodiments have been described above with reference to the drawings, the present disclosure is not restricted to those embodiments. It is apparent that those skilled in the art would be able to conceive various changes, modifications, replacements, additions, deletions, and equivalents without departing from the scope of the claims, and they should naturally be construed as belonging to the technical scope of the disclosure. Furthermore, constituent elements of some of the above-described various embodiments may be combined in a desired manner without departing from the spirit and scope of the disclosure.

INDUSTRIAL APPLICABILITY

The present disclosure is useful in providing camera devices and manufacturing systems capable of acquiring a clear image simply in a short time and thereby increasing the production efficiency.