Image measuring apparatus

Abstract

To provide an image measuring apparatus that can improve work efficiency without requiring any operation to start measurement.SOLUTION: An image measuring apparatus 1 comprises: a mounting table 2 on which an object to be measured is mounted; image capturing means 3 that is disposed facing the mounting table 2 and captures the image of the object to be measured; control means 4 that controls the image measuring apparatus; and storage means 5 that stores at least the shape of the object to be measured and a measuring method corresponding to the object to be measured in association with each other. The control means 4 includes: a mounting determination section 41 that determines whether the object to be measured is mounted on the mounting table 2 so as to be measured on the basis of the image captured by the image capturing means 3; and a measurement performing section 42 that selects the measuring method corresponding to the object to be measured on the basis of the shape of the object to be measured appearing in the image and performs the measurement when the mounting determination section 41 determines that the object to be measured is mounted so as to be measured.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an image measuring machine. [Background technology]

[0002] Vision measuring machines have been known as devices for measuring the dimensions of measurement objects (see, for example, Patent Document 1). Vision measuring machines use an imaging device to capture an image of a measurement object placed on a mounting table and illuminated by an illumination device, and measure the dimensions of each part using the image of the state of the measurement object obtained from the imaging device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-169584 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional image measuring machines, a user must manually operate the image measuring machine, for example by pressing a measurement start button, in order to start measurement and capture an image using an imaging device. In addition, the user may need to adjust the position of the measurement target before starting the measurement so that the measurement target is accurately measured. For this reason, conventional image measuring machines have the problem that it may take time and effort to start performing a measurement.

[0005] An object of the present invention is to provide an image measuring instrument that does not require any operation to start measurement execution, thereby improving work efficiency. [Means for solving the problem]

[0006] The image measuring instrument of the present invention includes a mounting table on which a measurement object is placed, an imaging means disposed opposite the mounting table and imaging an image of the measurement object, a storage means for storing at least the shape of the measurement object and a measurement method corresponding to the measurement object in association with each other, and a control means for controlling the image measuring instrument. The control means includes a mounting determination unit for determining whether the measurement object is placed on the mounting table in a measurable state based on the image captured by the imaging means, and a measurement execution unit for selecting a measurement method corresponding to the measurement object based on the shape of the measurement object shown in the image and executing the measurement when the mounting determination unit determines that the measurement object is placed in a measurable state.

[0007] According to the present invention, measurement can be started simply by placing the measurement object appropriately on the mounting table. Therefore, the image measuring instrument does not require a separate operation to start measurement, and the work efficiency can be improved.

[0008] The placement determination unit may constantly monitor changes in the image acquired by the imaging means, and if the image acquired by the imaging means is in a changing state, issue an interrupt end event to end the measurement by the measurement execution unit. The measurement execution unit may then divide the measurement into a plurality of measurement processes and execute them in sequence, and each time it executes one measurement process, determine whether or not it has received an interrupt end event, and if it has received an interrupt end event, end the measurement being executed.

[0009] With this configuration, if there is a change in the image acquired by the imaging means during measurement, the measurement can be quickly terminated, and as a result, the next measurement can be started immediately when a new static image is acquired.

[0010] In the present invention, when multiple measurement objects are captured in an image acquired by the imaging means, the measurement execution unit may perform measurements on each of the measurement objects. The storage unit may store shapes and measurement methods for multiple types of measurement objects in association with each other. When multiple types of measurement objects are captured in an image acquired by the imaging means, the measurement execution unit may select a measurement method corresponding to each measurement object based on the shape of each measurement object and perform the measurement. The measurement execution unit may also perform parallel processing of detection of multiple types of measurement objects captured in the image using multiple cores or threads of a processor (arithmetic processing device) that realizes the measurement execution unit, thereby further improving the responsiveness of simultaneous measurements.

[0011] According to such a configuration, a plurality of objects or a plurality of types of objects to be measured can be measured simultaneously.

[0012] It is preferable that the placement determination unit constantly monitors changes in the image acquired from the imaging means, detects whether the image has changed from a moving state to a stationary state, and determines that the object to be measured has been placed on the placement table in a measurable state if the object to be measured is captured in the stationary image in a measurable state.

[0013] According to this configuration, the image measuring instrument starts measurement when the object to be measured comes to rest on the mounting table, so that measurement can be started reliably without any operation by the user. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a diagram showing the appearance of an image measuring instrument. [Diagram 2] FIG. 2 is a schematic diagram showing an internal structure of the image measuring device. [Diagram 3] FIG. 2 is a functional block diagram of the image measuring machine. [Figure 4] 13 is a flowchart showing a processing procedure of a placement determination processing thread. [Diagram 5] 13 is a flowchart showing a processing procedure of a measurement program thread. [Figure 6] FIG. 4 is a diagram showing an initial screen displayed on a display unit of the image measuring device. [Figure 7] 13A and 13B are diagrams showing a state during judgment by a placement judgment unit displayed on a display unit of the image measuring device. [Figure 8] 13A and 13B are diagrams showing the results of measurement performed by the measurement execution unit and displayed on a display means of the image measuring machine. [Figure 9] 13A and 13B are diagrams showing other examples of measurement execution results by the measurement execution unit displayed on the display means of the image measuring machine. [Figure 10] FIG. 13 is a diagram showing the state when pausing, resuming, or canceling the measurement execution displayed on the display unit of the image measuring instrument. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. Fig. 1 is a schematic diagram showing the appearance of an image measuring machine 1 according to a first embodiment. Fig. 2 is a schematic diagram showing the internal structure of the image measuring machine 1. Fig. 3 is a functional block diagram of the image measuring machine 1. As shown in Figs. 1 to 3, the image measuring machine 1 includes a mounting table 2, an imaging means 3, a control means 4, a storage means 5, a display means 6, a telecentric optical system 7, an illumination means 8, and an operation means 10. The image measuring machine 1 captures an image of a measurement object (not shown) placed on the mounting table 2 using the imaging means 3, and calculates the captured image using the control means 4 to measure the dimensions of the measurement object, etc.

[0016] As shown in FIG. 1, the mounting table 2 has a top plate 21 on which a measurement object is placed and which transmits light near the center. The imaging means 3 is provided opposite the mounting table 2 and captures an image of the measurement object. The imaging means 3 has an image sensor. The image sensor converts the brightness of the image formed on its light receiving surface into an electric signal to generate image data. The image sensor may be a semiconductor solid-state imaging element such as a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The telecentric optical system 7 forms an image on the light receiving surface of light from, for example, the direction of the mounting table 2. The telecentric optical system 7 may have a large-diameter objective lens 71 that can include the entire range of the mounting table 2 within its field of view.

[0017] The illumination means 8 irradiates the measurement object with illumination light. The illumination means 8 may include, for example, a transmitted illumination 81, a ring illumination 82, a coaxial epi-illumination 83, and the like.

[0018] 2, the transmitted light 81 irradiates light from below the top plate 21 toward the imaging means 3. The ring light 82 is provided on the periphery of the objective lens. The coaxial epi-illumination 83 interrupts the telecentric optical system via a beam splitter and irradiates illumination light toward the mounting table 2. When imaging with the imaging means 3, the illumination to be used and its illuminance are appropriately selected so that a clear image is obtained without any unnecessary shadows on the object to be measured.

[0019] The storage means 5 is composed of, for example, a hard disk drive, a RAM, etc. The storage means 5 stores a program executed by the control means 4 to control each part in the image measuring machine 1, various data required for measurement, measurement results by the image measuring machine 1, etc. The storage means 5 stores at least the shape of the measurement object and the measurement method corresponding to the measurement object in association with each other. The shape of the measurement object is, for example, CAD (Computer Aided Design) data of the measurement object, an image of the actual measurement object, etc. The measurement method corresponding to the measurement object is, for example, a measurement program (part program) that specifies the location where the dimensions of the corresponding measurement object are to be measured, the allowable dimensional tolerance, etc. The storage means 5 may store the shapes and the measurement methods for multiple types of measurement objects in association with each other. When there are three types of parts A, B, and C with different shapes, the storage means 5 may store CAD data, which is data on the shapes of the parts A, B, and C, respectively, and may store part programs corresponding to the parts A, B, and C, respectively.

[0020] The control means 4 controls each unit in the image measuring instrument 1 to realize imaging and measurement by the image measuring instrument 1. The control means 4 may be realized by, for example, an arithmetic processing device such as a CPU (Central Processing Unit) executing a program stored in the storage means 5. In this embodiment, the control means 4 includes a placement determination unit 41 and a measurement execution unit 42.

[0021] The placement determination unit 41 executes a placement determination process thread that acquires an image captured by the imaging means 3 and determines whether or not the measurement object is placed on the placement table 2 in a measurable state based on the image. Specifically, the placement determination unit 41 constantly monitors changes in the image acquired by the imaging means 3 and detects whether or not the image has changed from a moving state to a stationary state. For example, the placement determination unit 41 may determine that the image acquired by the imaging means 3 has become stationary when there is no change for a predetermined time (e.g., 1 second). Then, when the measurement object is captured in a measurable state in the stationary state image, the placement determination unit 41 determines that the measurement object is placed on the placement table 2 in a measurable state. In the placement determination process thread, the placement determination unit 41 issues a measurement start event that triggers the measurement execution unit 42 to start a measurement program thread and an interrupt end event that interrupts the measurement program thread being executed. A detailed procedure of the placement determination process thread will be described later.

[0022] Note that "the measurement target is shown in the image in a measurable state" refers to the measurement target being shown in the image in a state where it can be measured as specified in the part program described below. For example, a state where only a part of the measurement target is shown in the image or a state where multiple measurement targets are shown overlapping each other does not fall under "shown in a measurable state."

[0023] The measurement execution unit 42 executes the measurement program thread when a measurement start event is issued in the placement determination processing thread. A detailed procedure of the measurement program thread will be described later. The placement determination processing thread by the placement determination unit 41 and the measurement program thread by the measurement execution unit 42 can be executed in parallel or in parallel as separate threads.

[0024] In the measurement program thread, a measurement method (part program) corresponding to the measurement object is selected based on the shape of the measurement object shown in the image captured by the imaging means 3, and measurement is performed. For example, when a part A is placed on the mounting table 2, the measurement execution unit 42 selects and executes a measurement method corresponding to the part A based on the shape of the measurement object shown in the image captured by the imaging means 3. When multiple types of measurement objects are simultaneously placed on the mounting table 2 (i.e., when multiple types of measurement objects are shown in the image acquired by the imaging means 3), the measurement execution unit 42 selects and executes a measurement method corresponding to each measurement object based on the shape of each measurement object. For example, when a part A and a part B are simultaneously placed on the mounting table 2, the measurement execution unit 42 executes a measurement method corresponding to the part A for the part A in the image, and executes a measurement method corresponding to the part B for the part B in the image. It is preferable that the measurement execution unit 42 detects multiple types of measurement objects shown in the image in parallel using multiple cores or threads of a processor (arithmetic processing device) that realizes the measurement execution unit 42. This can improve the responsiveness of simultaneous measurement. When an interrupt end event is issued in the placement determination processing thread during execution of the measurement program thread, the measurement execution unit 42 interrupts the measurement program thread being executed and ends the processing.

[0025] The measurement results obtained by the measurement execution unit 42 are displayed on display means 6, which displays information about the image measuring machine 1. If a command for saving the measurement results is set in advance in the part program of the image measuring machine 1, the measurement results are automatically saved in storage means 5. In addition to the measurement results, display means 6 displays, for example, information about whether the image measuring machine 1 is ready for use, information about the object to be measured stored in storage means 5, information about detailed settings of the image measuring machine 1, and the like. Display means 6 is a liquid crystal panel with a touch sensor. A user can use the liquid crystal panel with a touch sensor as operation means 10 to make detailed settings of the image measuring machine 1 and to turn the power of the image measuring machine 1 on and off.

[0026] Fig. 4 is a flowchart showing the procedure of the placement judgment processing thread executed by the placement judgment unit 41. Also, Fig. 5 is a flowchart showing the procedure of the measurement program thread executed by the measurement execution unit 42. The placement judgment processing thread corresponds to the main thread in measurement by the image measuring device 1, and the measurement program thread is a sub-thread called from the placement judgment processing thread as necessary.

[0027] Moreover, Fig. 6 is a diagram showing an initial screen displayed on the display means 6 of the image measuring device 1, and Fig. 7 is a diagram showing a state during judgment by the placement judgment unit displayed on the display means 6 of the image measuring device 1. Moreover, Figs. 8 and 9 are diagrams showing the measurement execution results by the measurement execution unit displayed on the display means 6 of the image measuring device 1. The procedure of measurement by the image measuring device 1 will be described below with reference to Figs. 4 and 5.

[0028] First, when the image measuring device 1 is started and a predetermined operation for starting measurement is received, the placement determination unit 41 starts a placement determination process thread as shown in FIG. 4 (START in FIG. 4). When the image measuring device 1 starts the placement determination process thread, it constantly monitors changes in the image acquired by the imaging means 3 and determines whether the image captured by the imaging means 3 is in a stationary state (step ST01). If there is no change in the image acquired by the imaging means 3 for a predetermined time (for example, 1 second) after the last change, the placement determination unit 41 determines that the image has become stationary (YES in step ST01) and proceeds to step ST03. On the other hand, if the placement determination unit 41 determines that the image has not become stationary (NO in step ST01), it issues an interrupt end event (step ST02) and returns the process to step ST01. With the issuance of the interrupt end event in step ST02, the measurement program thread being executed is interrupted and terminated. Steps ST01 and ST02 are repeated until the stationary state is reached. During this time, as shown in FIG. 7, the display means 6 may display "Ready" or the like to notify the user that the device is waiting for the object to be measured to be placed in a measurable state.

[0029] When it is determined in step ST01 that the image is in a stationary state, the placement determination unit 41 recognizes one measurement object that has not yet been measured from the image in the stationary state (step ST03), and determines whether the measurement object is captured in a measurable state (step ST04). When a measurement object having the same shape as the measurement object stored in the storage unit 5 is captured in a measurable state in the image captured by the imaging unit 3 (Yes in step ST04), the placement determination unit 41 moves the process to step ST06. On the other hand, when the measurement object is not captured in a measurable state in the image in the stationary state (No in step ST04), an interrupt end event is issued (step ST05), and the process returns to step ST01. With the issuance of the interrupt end event in step ST05, the measurement program thread being executed is interrupted and terminated.

[0030] When it is determined in step ST04 that the measurement object is captured in a state in which it can be measured, the placement determination unit 41 issues a measurement start event (step ST06). With the issuance of the measurement start event, the measurement execution unit 42 starts a measurement program thread for the measurement object recognized in step ST03. Then, it is determined whether or not an unmeasured measurement object is captured in the image in the stationary state (step ST07). If an unmeasured measurement object is not captured in the image in the stationary state (that is, if the measurement start event has been issued for all measurement objects) (step ST07 No), the placement determination unit 41 returns the process to step ST01 and continues to monitor the change in the image. On the other hand, if another measurement object is present in the image in the stationary state (step ST07 Yes), the placement determination unit 41 returns the process to step ST03, recognizes one new measurement object, and performs the same process as described above for the measurement object.

[0031] In this way, in the placement determination process thread, if there is even one measurement object that is not captured in a measurable state in the still image, an interrupt end event is issued and the process waits for a new still image to be obtained. Then, when an image is obtained in which all measurement objects are captured in a measurable state, the interrupt end event is not issued, and measurement start events are issued for all measurement objects, and the measurement execution unit 42 executes the measurement program thread unless an interrupt end event is issued due to circumstances such as a change in the image.

[0032] The measurement execution unit 42 starts a measurement program thread in response to the issuance of a measurement start event. When a plurality of measurement objects are captured in a still image in a measurable state, a measurement start event is issued for each measurement object. When a plurality of measurement start events are issued in this manner, the measurement execution unit 42 may execute the measurement program threads one by one in the order in which the measurement start events were issued. Alternatively, the measurement execution unit 42 may execute a plurality of measurement program threads in parallel.

[0033] The measurement execution unit 42 selects a part program corresponding to the recognized measurement object from among the part programs stored in the storage means 5 in the measurement program thread, and executes the measurement using the part program. A series of measurements to select and execute a part program may take from a few seconds to a few minutes. The measurement execution unit 42 divides a series of measurements into short measurement processes, and each time a divided measurement process is executed, it determines whether or not an interrupt end event occurs, and immediately interrupts and ends the measurement program thread if there is a change in the image or if it is found that there is even one measurement object in the image that is not in a measurable state.

[0034] FIG. 5 is a flowchart showing the processing procedure of the measurement program thread. When a measurement start event is issued, the measurement execution unit 42 starts the measurement program thread for the measurement object recognized in step ST03 of the placement judgment processing thread (START in FIG. 5). First, the measurement execution unit 42 divides a series of measurements, which are performed by selecting a part program, into multiple short-time (for example, 10 milliseconds or less) measurement processes (step ST11). Then, the measurement execution unit 42 executes one of the measurement processes that has not been executed yet that is the earliest in the processing order (step ST12). Next, the measurement execution unit 42 determines whether there is a next measurement process (step ST13). If there is a next measurement process (Yes in step ST13), the measurement execution unit 42 determines whether an interrupt end event has been received (step ST14).

[0035] On the other hand, if an interrupt end event has not been received in step ST14 (No in step ST14), the measurement execution unit 42 returns the process to step ST12 and executes the next measurement process. In this manner, steps ST12 to ST14 are repeated until it is determined in step ST13 that there is no next measurement process. If it is determined in step ST13 that there is no next measurement process (No in step ST13; that is, all measurement processes have been executed), the measurement execution unit 42 ends the measurement program thread. At that time, a measurement end event may be issued to indicate that the measurement program thread has ended by executing the measurement to the end, and the measurement execution unit 42 may start the measurement program thread corresponding to the next measurement start event using the issuance of the measurement end event as a trigger.

[0036] When the measurement is performed to the end and the measurement program thread is terminated, the measurement results are stored in the storage means 5 and are displayed on the display means 6 as shown in Figures 8 and 9. After that, as shown in Figure 8, the display means 6 may display a message such as "Measurement completed. Please place the next measurement object" to prompt the user to place the next measurement object.

[0037] The method of displaying the measurement results on the display means 6 is arbitrary. For example, it is good to display the dimension line of the location defined in the part program and its measurement value on the measurement object in the image captured by the imaging means 3. Also, if the dimensional tolerance of the measurement location is defined in the part program, it is possible to judge whether the measurement value of the location falls within the tolerance, and to display the judgment result so as to be superimposed on the measurement object in the image captured by the imaging means 3. For example, if the dimension of the measured part does not fall within the tolerance, a symbol such as "!" may be displayed on the image of the part displayed on the display means 6 (see FIG. 9) to notify the user of the presence of a dimensional abnormality.

[0038] On the other hand, if an interrupt end event is received in step ST14 (Yes in step ST14), the measurement is interrupted and the measurement program thread is terminated. With this configuration, the measurement execution unit 42 determines whether or not an interrupt end event has occurred each time it executes one of the short measurement processes into which the series of measurements is divided during execution of the measurement program thread, so that if a change occurs in the image during execution of the measurement program thread, or if it is found that a measurement target that is not captured in a measurable state is present in the image, it is possible to quickly interrupt the measurement and terminate the measurement program thread without waiting for the series of measurements to be executed to the end.

[0039] Fig. 10 is a diagram showing the state when pausing, resuming, or canceling the measurement execution displayed on the display means 6 of the image measuring device 1. Basically, the image measuring device 1 can measure the object to be measured without the user having to perform an operation to start the measurement execution, as in the measurement process described above, but as shown in Fig. 10, the user can also operate the operation means 10 such as a touch panel to pause, resume, or cancel the measurement execution. By allowing such operations, even if a situation arises in which it is necessary to interrupt the measurement midway, the user can immediately respond by operating the operation means 10.

[0040] According to such an embodiment of the present invention, the following actions and effects can be achieved. (1) The placement determination unit 41 in the vision measuring machine 1 acquires an image of the placement table 2 and determines based on the image whether the measurement object is placed in a measurable state, and the measurement execution unit 42 selects a measurement method corresponding to the measurement object based on the shape of the measurement object shown in the image and executes the measurement. This allows measurement to be executed simply by placing the measurement object on the placement table 2. Therefore, the vision measuring machine 1 does not require any special operation to start measurement, making it possible to improve work efficiency.

[0041] [Modifications of the embodiment] It should be noted that the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of the present invention that can achieve the object of the present invention are included in the present invention. For example, as long as an image measuring instrument is equipped with a mounting stage on which an object to be measured is placed, and an imaging means arranged opposite the mounting stage and which captures an image of the object to be measured, the type of detector, the detection method, etc. are not particularly limited.

[0042] In each of the above embodiments, the placement determination unit 41 determines that the measurement object is "placed in a measurable state" when the measurement object is shown in a measurable state in the image of a stationary state captured by the imaging means 3, but the method of determining whether or not the measurement object is "placed in a measurable state" is not limited to this. For example, the placement determination unit 41 may determine that the measurement object is "placed in a measurable state" when the measurement object is shown in a measurable state in the image, regardless of whether the image captured by the imaging means 3 is in a stationary state or not.

[0043] In each of the above-mentioned embodiments, a warning unit may be provided that issues a warning when the measurement object is not measurable in the image captured by the imaging means. For example, a warning may be issued when only a part of the measurement object is captured in the image, when multiple measurement objects are captured overlapping, when the measurement object is placed in an incorrect orientation, etc. In addition, the warning unit may issue a warning when an object captured in an image acquired from the imaging means does not match the shape (CAD data) of the measurement object stored in the storage means 5. The method of issuing a warning is arbitrary. For example, the display means may display a message indicating that the measurement cannot be started, or the color of the display screen of the display means or the color of the displayed characters may be changed to issue a warning. In addition, a warning may be issued by sounding a buzzer or the like, by applying a stimulus to the human body in contact with the displacement measuring instrument, or by generating vibrations. Furthermore, a warning may be issued using light, such as by lighting or blinking a light-emitting member such as an LED, or by adjusting the amount of light of the backlight of the display screen. [Industrial Applicability]

[0044] As described above, the present invention can be suitably used in an image measuring machine. [Explanation of symbols]

[0045] 1. Image measuring device 2. Placement table 3. Imaging Method 4. Control Measures 41 Placement Judgment Section 42 Measurement Execution Unit

Claims

1. An image measuring machine including: a mounting table for mounting a measurement object; an imaging means for capturing an image of the measurement object, the imaging means being disposed opposite the mounting table; and a storage means for storing at least a shape of the measurement object and a measurement method corresponding to the measurement object in association with each other, A control unit for controlling the image measuring device is provided. The control means a placement determination unit that determines whether or not the measurement object is placed on the placement table in a state in which the measurement object can be measured, based on an image captured by the imaging means; and a measurement execution unit that, when the placement determination unit determines that the measurement object is placed in a measurable state, selects a measurement method corresponding to the measurement object based on the shape of the measurement object shown in an image and executes the measurement.

2. the placement determination unit constantly monitors a change in the image acquired by the imaging means, and when the image acquired by the imaging means indicates a change, issues an interrupt end event to end the measurement by the measurement execution unit; The measurement execution unit is Divide the measurement into multiple measurement processes and execute them sequentially, Each time one of the measurement processes is executed, it is determined whether or not the interrupt end event has been received; Terminates ongoing measurement when an interrupt end event is received 2. The image measuring device according to claim 1,

3. 3. The image measuring instrument according to claim 1, wherein, when a plurality of measurement objects are captured in the image acquired by the imaging means, the measurement execution unit executes measurement for each of the measurement objects.

4. The storage means stores shapes and measurement methods for a plurality of types of measurement objects in association with each other, 3. The image measuring instrument according to claim 1, wherein when a plurality of types of measurement objects are captured in the image acquired by the imaging means, the measurement execution unit selects a measurement method corresponding to each measurement object based on the shape of each measurement object and executes the measurement.

5. The placement determination unit is 3. The image measuring machine according to claim 1, further comprising: a measuring device that constantly monitors changes in an image acquired by the imaging means; detects whether the image has changed from a moving state to a stationary state; and, if the image in the stationary state shows the object to be measured in a measurable state, determines that the object to be measured has been placed in a measurable state.

Images