JP7303074B2 - Image measuring machine and image measuring method - Google Patents

Description

The present invention relates to an image measuring machine and an image measuring method.

2. Description of the Related Art An image measuring machine is used to measure the shape and dimensions of a workpiece from an image obtained by imaging the workpiece. Image measuring machines perform edge detection processing on images (processing for extracting bright and dark boundaries on an image and capturing ridgelines of workpieces, etc.) (see Patent Document 1).
An image measuring machine is required to capture images to be subjected to edge detection processing and the like under conditions suitable for measurement. However, due to differences in the surface shape and material of the work, it is difficult to obtain the best state of the entire screen if the images are taken under the same conditions. For this reason, conditions such as illumination and exposure time are adjusted for each region of the surface of the work, and the work is imaged in multiple times (see Patent Document 2).

A wide dynamic range function (WDR function) is known in an imaging device for photographing people, articles, or landscapes, although it is different from image measuring instruments.
The WDR function sets two frames, a long-exposure frame and a short-exposure frame, during the shooting time (exposure time), which is usually one frame, and synthesizes the images obtained from each. . With this WDR function, for example, even when the background is bright and the person is dark, the short-exposure frame for the bright background avoids overexposure, while the long-exposure frame is used for the dark person to obtain a sufficient amount of light. (See Patent Documents 3 and 4).

JP 2017-49050 A JP 2017-151085 A JP 2017-224905 A JP 2009-88929 A

As described above, in the image measuring machine, when the imaging conditions differ for each area of the workpiece, it is necessary to repeat setting and imaging for each area.
On the other hand, by referring to the WDR function described above and dividing the normal imaging time into a plurality of times and combining imaging operations with different exposure times, even if the imaging conditions differ for each region of the workpiece, each A composite image may be obtained in which the areas are properly exposed.
However, even if the existing WDR function is used as it is, it is not possible to obtain the image required for the image measuring machine, that is, the image suitable for edge detection. In other words, it is necessary to appropriately set the exposure time of multiple images, which are the basis of the composite image, according to the workpiece, so that the image is suitable for the image measuring machine. was requested.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image measuring instrument and an image measuring method capable of efficiently processing imaging under a plurality of exposure conditions.

The image measuring machine of the present invention has a camera for capturing an image of a workpiece, an image capturing control section for controlling an image capturing operation of the camera, and an image processing section for processing an image signal from the camera. a time-division imaging setting unit for setting a long exposure time and a short exposure time when imaging with the camera; and a time-division imaging control unit for causing the camera to perform an imaging operation in each of the long exposure time and the short exposure time. wherein the image processing unit synthesizes the workpiece from a long-exposure image of the workpiece captured with the long exposure time and a short-exposure image of the workpiece captured with the short exposure time. The time-division imaging setting unit includes a contrast detection unit for detecting a contrast value of the image of the workpiece captured by the camera, and the and an exposure mode setting unit that sets a long exposure time and the short exposure time.

According to the present invention, when an image of a workpiece is imaged, a normal imaging period for one frame can be time-divided to perform imaging with a long exposure time and a short exposure time. A composite image of the workpiece can be obtained from the image and the short exposure image. From the obtained composite image, it is possible to extract the image component from the long-time exposure and the image component from the short-time exposure. can be imaged.
The setting of long exposure time and short exposure time is carried out in the time-division imaging setting section by performing provisional imaging of the work using the provisional exposure time, and obtaining an image suitable for edge detection based on the contrast value of the obtained image. A long exposure time and a short exposure time suitable for edge detection in an image measuring machine can be set by selecting the temporary exposure time.
Therefore, the image measuring instrument of the present invention can efficiently process imaging under a plurality of exposure conditions.

In the image measuring machine of the present invention, the exposure mode setting section sets the camera to different exposure times, and among a plurality of images obtained by imaging the work, the contrast value is equal to or greater than a predetermined reference value. The long exposure time may be the exposure time of the image having the longest exposure time, and the short exposure time may be the exposure time of the image having the contrast value equal to or greater than a predetermined reference value and the shortest exposure time. preferable.

In the present invention, the upper limit (longest exposure time) and the lower limit (shortest exposure time) of the range in which the contrast value is equal to or greater than a predetermined reference value among the images of the workpiece with various exposure times obtained by temporary imaging. ) to easily set these as long and short exposure times.
When setting different exposure times for the camera to obtain a plurality of images, a predetermined maximum exposure time and minimum exposure time are set, multiple exposure times are set within that range, and each exposure is The work may be imaged by a camera in time. These maximum exposure time value and minimum exposure time value are the maximum and minimum values that can be set in the camera or the image processing section, and may be appropriately selected according to the operating speed and processing speed of each.

In the image measuring instrument of the present invention, the exposure mode setting section has a long exposure mode setting section and a short exposure mode setting section, and the long exposure mode setting section sequentially sets the exposure time from the maximum value. detecting the contrast value of an image captured with a short exposure time, and setting the exposure time of the image in which the obtained contrast value is equal to or greater than the reference value as the long exposure time, wherein the short exposure mode setting unit The contrast value is detected for images captured with successively longer exposure times from the minimum exposure time, and the exposure time of the image in which the obtained contrast value is equal to or greater than the reference value is set as the short exposure time. preferable.

In the present invention as described above, the long exposure mode setting and the short exposure mode setting can be separated, and each can be operated independently. For example, long-exposure mode setting and short-exposure mode setting can be executed in parallel, and the processing time required for setting long-exposure time and short-exposure time can be minimized.
If the long exposure mode setting and the short exposure mode setting are not separated, for example, the short exposure time is set first (when the contrast value is equal to or greater than the ), and then set a long exposure time (when the contrast value is no longer equal to or greater than the reference value). In this case, the inspection is continued even in the range of exposure time in which the contrast value is equal to or greater than the reference value, which lengthens the work time. On the other hand, by separating the long-time exposure mode setting and the short-time exposure mode setting, it is possible to omit the inspection of the exposure time range in which the contrast value is equal to or greater than the reference value, and perform an efficient setting operation. be able to.
The long-time exposure mode setting and the short-time exposure mode setting may be performed individually, that is, may be performed sequentially in series.

The image measuring method of the present invention uses an image measuring machine having a camera for capturing an image of a workpiece, an image capturing control section for controlling the image capturing operation of the camera, and an image processing section for processing an image signal from the camera. and a contrast detection step of detecting a contrast value of an image of the work imaged by the camera as a time-division imaging setting step of setting a long exposure time and a short exposure time when imaging with the camera by the imaging control unit. and an exposure mode setting step of setting the long exposure time and the short exposure time based on the obtained contrast value, and then the imaging control unit causes the long exposure time and the short exposure executing a time-division imaging control step for causing the camera to perform an imaging operation at each time, and then, by the image processing unit, a long-exposure image of the workpiece imaged with the long exposure time and the short-exposure time and an image synthesizing step of generating a synthetic image of the workpiece from the short-time exposure image of the workpiece imaged in the step.
According to the present invention, it is possible to obtain the same effects as described for the image measuring machine of the present invention.

In the image measuring method of the present invention, in the exposure mode setting step, among a plurality of images obtained by imaging the workpiece with the camera set to different exposure times, the contrast value is equal to or greater than a predetermined reference value. The long exposure time may be the exposure time of the image having the longest exposure time, and the short exposure time may be the exposure time of the image having the contrast value equal to or greater than a predetermined reference value and the shortest exposure time. preferable.
According to the present invention, it is possible to obtain the same effects as described for the image measuring machine of the present invention.

In the image measuring method of the present invention, the exposure mode setting step includes a long exposure mode setting step and a short exposure mode setting step, and in the long exposure mode setting step, the exposure time is set sequentially from the maximum exposure time. The contrast value is detected for an image captured with a short exposure time, and the exposure time of the image in which the obtained contrast value is equal to or greater than the reference value is set as the long exposure time, and in the short exposure mode setting step The contrast value is detected for images captured with successively longer exposure times from the minimum exposure time, and the exposure time of the image in which the obtained contrast value is equal to or greater than the reference value is set as the short exposure time. preferable.
According to the present invention, it is possible to obtain the same effects as described for the image measuring machine of the present invention.

According to the present invention, it is possible to provide an image measuring instrument and an image measuring method capable of efficiently processing imaging under a plurality of exposure conditions.

1 is a perspective view showing an image measuring machine according to a first embodiment of the present invention; FIG. 4 is a graph showing time-division imaging processing of the first embodiment; The block diagram which shows the control apparatus of the said 1st Embodiment. 5 is a graph showing the exposure mode setting operation of the first embodiment; 4 is a graph showing contrast values detected in the first embodiment; 4 is a flowchart showing time-division imaging processing according to the first embodiment; 9 is a graph showing an exposure mode setting operation according to the second embodiment of the present invention; 9 is a graph showing exposure mode setting operation of the third embodiment of the present invention; FIG. 10 is a graph showing time-division imaging processing according to the fourth embodiment of the present invention; FIG. 9 is a graph showing contrast values detected in the fourth embodiment;

[First Embodiment]
FIG. 1 shows an image measuring machine 1 which is a first embodiment of the present invention.
The image measuring machine 1 takes an image of the surface of the work 2 with a camera 3 and measures the shape and dimensions of the work 2 from the obtained image.
A workpiece 2 to be measured is supported by a table 4 and is movable relative to the camera 3 .

The image measuring machine 1 comprises a control device 10 for controlling the camera 3 and for processing the obtained image data.
The control device 10 is configured by connecting a display device 12 and an operation device 13 to a control device body 11 using a general personal computer system. As the operation device 13, a keyboard 14, a mouse 15 as a pointing device, a pad 18 having a joystick 16 and a jog dial 17, and the like can be used as appropriate.

The control device 10 performs time-division imaging processing when imaging with the camera 3 .
In FIG. 2, when capturing an image of the workpiece 2, the control device 10 time-divides a normal image capturing period TF for one frame, and performs image capturing with a long exposure time TL and a short exposure time TS. In each image pickup, the light amount L increases according to the exposure time. Therefore, a sufficient amount of light L can be obtained in imaging with the long exposure time TL, and the amount of light L can be suppressed in imaging with the short exposure time TS. The obtained images with different exposure times are combined into a composite image for one frame.
With such a time-division imaging process, even if there is a large difference in the optical characteristics of each part of the surface of the work 2, it is possible to obtain a clear image of the work 2 in any of the exposure time image components included in the composite image. can.

In FIG. 3, the control device 10 executes an operation program loaded in the control device main body 11 to configure an imaging control section 20 and an image processing section 30 for performing the above-described time-division imaging processing.
The imaging control unit 20 includes a time-division imaging setting unit 21 that sets the long exposure time TL and the short exposure time TS when imaging with the camera 3, and the imaging operation of the camera 3 with the long exposure time TL and the short exposure time TS. and a time-division imaging control unit 22 to be executed.

The time-division imaging setting unit 21 has a contrast detection unit 23 that detects the contrast value C of the image of the workpiece 2 captured by the camera 3, and a long exposure time TL and a short exposure time TS based on the obtained contrast value C. and an exposure mode setting unit (long-time exposure mode setting unit 24 and short-time exposure mode setting unit 25) for setting.

The contrast detection unit 23 detects the contrast value C of the designated image using an existing calculation method. As the image of the workpiece 2 from which the contrast value C is detected, the long-exposure image VL and the short-exposure image VS stored in the long-exposure image storage unit 31 and the short-exposure image storage unit 32, which will be described later, can be used. . Note that the contrast detection unit 23 may capture an image directly from the camera 3 .

The long-time exposure mode setting unit 24 and the short-time exposure mode setting unit 25 respectively set the temporary exposure time, perform temporary imaging of the workpiece 2 with the camera 3, and sequentially change the temporary exposure time while the contrast value C of each image is changed. is compared with a preset reference value Cr (see FIG. 5) to set the long exposure time TL and short exposure time TS suitable for the surface shape of the workpiece 2 .
At this time, the variation width of the provisional exposure time is set within the range from the maximum exposure time value Tm to the minimum exposure time value Tn (see FIG. 4) that can be set in the camera 3 and the control device 10 . Note that FIG. 4 shows the relationship between the exposure time T and the elapsed time t. FIG. 5 shows the relationship between contrast value C and exposure time T. In FIG.
Note that the maximum exposure time value Tm to the minimum exposure time value Tn are the maximum and minimum values that can be set in the camera 3 or the image processing unit 30, and can be appropriately selected according to the operation speed and processing speed of each. good.

As shown in the upper part of FIG. 4, the long exposure mode setting unit 24 sets temporary long exposure times TLt that are successively shorter from the maximum exposure time Tm, performs temporary imaging with the temporary long exposure times TLt, and obtains an image. , the detection of the contrast value C by the contrast detection unit 23 is repeated.
Then, as shown on the right side of FIG. 5, when the contrast value C of the image obtained with the provisional long exposure time TLt becomes equal to or greater than the reference value Cr, the repetition of provisional imaging is stopped, and this image is obtained. The obtained current provisional long exposure time TLt is set as the long exposure time TL (long exposure mode setting operation).

As shown in the lower part of FIG. 4, the short-time exposure mode setting unit 25 sets temporary short-exposure times TSt that are successively longer from the minimum exposure time Tn, performs temporary imaging with the temporary short-exposure times TSt, and obtains an image. , a contrast value C is detected by the contrast detection unit 23 .
Then, as shown on the left side of FIG. 5, when the contrast value C of the image obtained with the provisional short exposure time TSt becomes equal to or greater than the reference value Cr, the repetition of provisional imaging is stopped, and this image is obtained. The obtained current provisional short exposure time TSt is set as the short exposure time TS (short time exposure mode setting operation).

The image processing unit 30 stores a long exposure image VL of the workpiece 2 captured with the long exposure time TL, and a short exposure image VS of the workpiece 2 captured with the short exposure time TS. and an image combining unit 33 for generating a combined image VC of the workpiece 2 from the long-time exposure image VL and the short-time exposure image VS. The synthesized image VC obtained is stored in the synthesized image storage unit 34 .

[Processing procedure of the first embodiment]
FIG. 6 shows a processing procedure in the image measuring machine 1 of this embodiment.
When performing image measurement of the work 2 with the image measuring machine 1, first, the work 2 to be measured is set on the image measuring machine 1, the control device 10 is activated, the camera 3 is adjusted, and the image of the work 2 is detected. It is ready (process S1 in FIG. 6).
The controller 10 sets the long exposure time TL (processes S2 to S5, long exposure mode setting operation) and the short exposure time TS (processes S6 to S9, short exposure mode setting operation) necessary for the time-division imaging process. ) is executed.

For the long-time exposure mode setting operation, the long-time exposure mode setting unit 24 repeats the processes S2 to S4 until the end is determined in the process S4.
In the first iteration, the maximum exposure time value Tm is set as the temporary long exposure time TLt, temporary imaging is performed in this state (process S2), the contrast value C of the temporarily imaged image is detected (process S3), The obtained contrast value C is compared with the reference value Cr (process S4), and if the contrast value C is not equal to or greater than the reference value Cr, the process returns to process S2.
In the second and subsequent repetitions, a value smaller than the maximum exposure time value Tm by a predetermined difference is set as the temporary long exposure time TLt, temporary imaging is performed with this setting (process S2), and the contrast value of the temporarily captured image is set. C is detected (process S3), the obtained contrast value C is compared with the reference value Cr (process S4), and if the contrast value C is not greater than the reference value Cr, the process returns to process S2.
If the contrast value C is equal to or greater than the reference value Cr in process S4, the temporary long exposure time TLt at that time is set to the long exposure time TL (process S5).

Through the above processes S2 to S5, the temporary long exposure time TLt gradually decreases from the maximum exposure time Tm as shown in the upper part of FIG. When a provisional image is obtained that exceeds the reference value Cr, the repetition ends, and the provisional long exposure time TLt at that time is set as the long exposure time TL.

For the short-time exposure mode setting operation, the short-time exposure mode setting unit 25 repeats the processes S6 to S8 until it is determined to end in the process S8.
In the first iteration, the minimum exposure time Tn is set as the provisional short exposure time TSt, provisional imaging is performed in this state (process S6), the contrast value C of the provisionally captured image is detected (processing S7), The obtained contrast value C is compared with the reference value Cr (process S8), and if the contrast value C is not equal to or greater than the reference value Cr, the process returns to process S6.
In the second and subsequent repetitions, a value larger than the minimum exposure time value Tn by a predetermined difference is set as the provisional short exposure time TSt, provisional imaging is performed with this setting (process S6), and the contrast value of the provisionally captured image is set. C is detected (process S7), the obtained contrast value C is compared with the reference value Cr (process S8), and if the contrast value C is not greater than the reference value Cr, the process returns to process S6.
If the contrast value C is equal to or greater than the reference value Cr in process S8, the temporary short exposure time TSt at that time is set to the short exposure time TS (process S9).

Through the processes S6 to S9 described above, the temporary short exposure time TSt gradually increases from the minimum exposure time Tn as shown in the lower part of FIG. When a provisional image is obtained that exceeds the reference value Cr, the repetition ends, and the provisional short exposure time TSt at that time is set as the short exposure time TS.

The long exposure mode setting operations (processes S2 to S5) and the short exposure mode setting operations (processes S6 to S9) described above are executed simultaneously in parallel, that is, in a state where they overlap over the elapsed time t, as shown in FIG. be done.
The set long exposure time TL and short exposure time TS are sent to the time-division imaging control unit 22, and the time-division imaging shown in FIG. 2 is performed (process S10).
In time-division imaging, a long exposure image VL is obtained by imaging with a long exposure time TL and stored in the long exposure image storage unit 31 . Also, a short-time exposure image VS is obtained by imaging with the short-time exposure time TS, and is stored in the short-time exposure image storage unit 32 . The long-time exposure image VL and the short-time exposure image VS are synthesized on the same frame by the image synthesizing unit 33, and a synthesized image VC is obtained in the synthesized image storage unit 34 (process S11).

The image measuring machine 1 performs image measurement processing on the synthesized image VC (processing S12). At this time, since the composite image VC includes the long-time exposure image VL and the short-time exposure image VS, even if the brightness is greatly different at each part of the surface of the work 2, the long-time exposure image VL and the short-time exposure image VS can be processed as a clear image by either

[Effect of the first embodiment]
According to this embodiment described above, the following effects can be obtained.
In the present embodiment, when an image of the workpiece 2 is captured by the camera 3, the image capturing period TF for one normal frame can be time-divided to capture images with the long exposure time TL and the short exposure time TS. A composite image VC of the workpiece 2 can be obtained from the long-time exposure image VL and the short-time exposure image VS.
From the obtained composite image VC, it is possible to extract the image component with the long exposure time TL and the image component with the short exposure time TS. Appropriate imaging can be performed with long and short exposure times (TL, TS).

In this embodiment, the time-division imaging setting unit 21 performs temporary imaging of the workpiece 2 with the temporary long exposure time TLt and the temporary short exposure time TSt that change sequentially, and the contrast value C of the obtained image (VL, VS) is set to By selecting the temporary long exposure time TLt and the temporary short exposure time TSt for obtaining an image suitable for edge detection and the like through sequential inspection, the long exposure time TL and the short exposure time suitable for edge detection and the like in the image measuring machine 1 are selected. TS can be set.
Therefore, the image measuring instrument 1 of the present embodiment can efficiently process imaging under a plurality of exposure conditions (long exposure time TL and short exposure time TS).

In this embodiment, when setting the long exposure time TL and the short exposure time TS based on the contrast value C, various images obtained by provisionally imaging the work 2 with the provisional long exposure time TLt and the provisional short exposure time TSt Among them, by selecting the upper limit (longest provisional long exposure time TLt) and the lower limit (shortest provisional short exposure time TSt) of the range in which the contrast value C is equal to or greater than a predetermined reference value Cr, the long exposure time TL and short exposure time TS can be easily set.

In this embodiment, the long exposure mode setting unit 24 for setting the long exposure time TL using the provisional long exposure time TLt and the short exposure mode setting unit 25 for setting the short exposure time TS using the provisional short exposure time TSt are separated. bottom. Therefore, the long-time exposure mode setting operation by the long-time exposure mode setting unit 24 and the short-time exposure mode setting operation by the short-time exposure mode setting unit 25 can be executed independently.
In particular, the long exposure mode setting operation by the long exposure mode setting unit 24 and the short exposure mode setting operation by the short exposure mode setting unit 25 can be executed in parallel, and the long exposure time TL and The processing time required for setting the short exposure time TS can be minimized.

In this embodiment, in the long exposure mode setting operation, the temporary long exposure time TLt is gradually decreased from a predetermined maximum exposure time Tm, and the long exposure time TL is set when the contrast value C exceeds the reference value Cr. bottom. In the short exposure mode setting operation, the temporary short exposure time TSt is gradually increased from the predetermined minimum exposure time Tn, and the short exposure time TS is set when the contrast value C exceeds the reference value Cr.
For this reason, it is possible to omit the inspection of the appropriateness of the exposure time for the area with the maximum exposure time Tm or more and the area with the minimum exposure time Tn or less, which are not used in the image measuring machine 1, and the setting operation can be performed efficiently. can.
Also, the change in the provisional long exposure time TLt in the long exposure mode setting operation and the provisional short exposure time TSt in the provisional time exposure mode setting operation proceed so as to approach each other from both sides of the time axis. Inspection of the intermediate area between the selected long exposure time TL and short exposure time TS can be omitted, and the work time can be shortened in this respect as well.

[Second embodiment]
FIG. 7 shows a second embodiment of the invention.
In this embodiment, the configuration of the image measuring machine 1 is the same as that of the above-described first embodiment, so redundant description will be omitted, and differences will be described below.
In the first embodiment described above, the long-time exposure mode setting operation by the long-time exposure mode setting unit 24 and the short-time exposure mode setting operation by the short-time exposure mode setting unit 25 are concurrently performed.
In contrast, in the present embodiment, the long exposure mode setting operation by the long exposure mode setting unit 24 and the short exposure mode setting operation by the short exposure mode setting unit 25 are sequentially executed in series.

In FIG. 7, in this embodiment, the short exposure mode setting unit 25 first performs temporary imaging while gradually increasing the temporary short exposure time TSt from the minimum exposure time Tn, inspects the contrast value C, and determines whether the short exposure time is Set TS (short-time exposure mode setting operation). Subsequently, the long-time exposure mode setting unit 24 performs temporary imaging while gradually decreasing the temporary long-exposure time TLt from the maximum exposure-time value Tm, checks the contrast value C, and sets the long-exposure time TL (long-time exposure mode setting operation).
According to this embodiment, it takes time to set the long exposure time TL and the short exposure time TS. are not duplicated, the computational load required for transferring image data from the camera 3 and image processing can be reduced, and the control device 10 can be configured using a relatively low-cost personal computer.

[Third embodiment]
FIG. 8 shows a third embodiment of the invention.
In this embodiment, the configuration of the image measuring machine 1 is the same as that of the above-described first embodiment, so redundant description will be omitted, and differences will be described below.
In the first embodiment described above, the long exposure mode setting section 24 and the short exposure mode setting section 25 are separated, and the provisional long exposure time TLt and the provisional short exposure time TSt are gradually increased and decreased.
In contrast, in this embodiment, the long exposure mode setting unit 24 is omitted, and the long exposure time TL and the short exposure time TS are set only by the short exposure mode setting unit 25 .

In FIG. 8, in this embodiment, first, the short exposure mode setting unit 25 performs temporary imaging while gradually increasing the temporary short exposure time TSt from the minimum exposure time Tn, inspects the contrast value C, and determines the short exposure time. Set TS (short-time exposure mode setting operation). Subsequently, in the same short-time exposure mode setting unit 25, provisional imaging is performed while gradually increasing the provisional short-exposure time TSt, and the maximum provisional short-exposure time TSt in which the contrast value C exceeds the reference value Cr is detected. The short exposure time TSt is set as the long exposure time TL (long exposure mode setting operation).
According to this embodiment, the single short exposure mode setting unit 25 can set the long exposure time TL and the short exposure time TS. Further, the long exposure time TL and the short exposure time TS can be set only by evaluating the contrast value C during a series of operations for gradually increasing the temporary short exposure time TSt. However, it may take time to set the long exposure mode from setting the short exposure time TS to setting the long exposure time TL.

[Fourth Embodiment]
9 and 10 show a fourth embodiment of the invention.
In this embodiment, the configuration of the image measuring machine 1 is the same as that of the above-described first embodiment, so redundant description will be omitted, and differences will be described below.
In the first embodiment described above, when an image of the workpiece 2 is captured by the camera 3, the normal one-frame image capturing period TF is divided into two, a long exposure time TL and a short exposure time TS.
On the other hand, in the present embodiment, the normal one-frame imaging period TF is divided into three, a long exposure time TL, a short exposure time TS1, and a short exposure time TS2 (see FIG. 9).

According to this embodiment as well, by synthesizing the images captured with the long exposure time TL, the short exposure time TS1, and the short exposure time TS2, the synthesized image VC obtained with the long exposure time TL The component, the image component with the short exposure time TS1, and the image component with the short exposure time TS2 can be taken out, and even when three exposure times T are required to image the workpiece 2, it can be handled.
In setting the long exposure time TL, the short exposure time TS1, and the short exposure time TS2, the configuration of the first embodiment described above can be used as it is.
In FIG. 10, for the long exposure time TL, the long exposure mode setting operation by the long exposure mode setting unit 24 is used as it is. On the other hand, as for the short exposure time TS1 and the short exposure time TS2, the short exposure time TS1 is first selected by the short exposure mode setting operation by the short exposure mode setting unit 25, and then the temporary short exposure time TSt is gradually increased. Based on the contrast value C, the short exposure time TS2 can be selected.

[Modification]
It should be noted that the present invention is not limited to the above-described embodiments, and includes modifications within the scope of achieving the object of the present invention.
In time-division of the imaging period TF for one normal frame, the long exposure time TL and the short exposure time TS may be arbitrarily set. Moreover, the number of time-divisions is not limited to two as in the first embodiment and three as in the fourth embodiment, but may be more.
The specific configuration of the imaging control unit 20 or the image processing unit 30 may be another configuration that can achieve the functions described above. For example, the contrast detection unit 23 may be incorporated in the long exposure mode setting unit 24 and the short exposure mode setting unit 25, respectively, and the same processing routine is performed for the long exposure mode setting unit 24 and the short exposure mode setting unit 25. The long exposure time TL and the short exposure time TS may be used separately.
In addition, the configuration of each part of the image measuring machine 1, for example, the specific configuration of the camera 3, the display device 12, and the operation device 13 can be appropriately selected in implementation.

INDUSTRIAL APPLICABILITY The present invention can be used for image measuring machines and image measuring methods.

DESCRIPTION OF SYMBOLS 1... Image measuring machine 2... Work 3... Camera 4... Table 10... Control device 11... Control device main body 12... Display device 13... Operation device 14... Keyboard 15... Mouse 16... Joystick , 17... Jog dial, 18... Pad, 20... Imaging control unit, 21... Time-division imaging setting unit, 22... Time-division imaging control unit, 23... Contrast detection unit, 24... Long exposure mode setting unit, 25... Short time Exposure mode setting unit 30 Image processing unit 31 Long-time exposure image storage unit 32 Short-time exposure image storage unit 33 Image synthesizing unit 34 Combined image storage unit C Contrast value Cr Reference value, L... light intensity, t... elapsed time, T... exposure time, TF... imaging period, TL... long exposure time, TLt... provisional long exposure time, Tm... maximum exposure time, Tn... minimum exposure time, TS, TS1, TS2...short exposure time, TSt...temporary short exposure time, VC...composite image, VL...long exposure image, VS...short exposure image.

Claims (6)

a camera for capturing an image of a workpiece, an image capturing control section for controlling the image capturing operation of the camera, and an image processing section for processing an image signal from the camera,
The imaging control unit includes a time-division imaging setting unit that sets a long exposure time and a short exposure time when imaging with the camera, and a time division imaging setting unit that causes the camera to perform an imaging operation in each of the long exposure time and the short exposure time. and a split imaging control unit,
The image processing unit generates a composite image of the workpiece from a long-exposure image of the workpiece captured with the long exposure time and a short-exposure image of the workpiece captured with the short exposure time. having a synthesis section,
The time-division imaging setting unit includes a contrast detection unit that detects the contrast value of the image of the workpiece captured by the camera, and a temporary exposure time that is sequentially shortened from a predetermined maximum exposure time value or from a predetermined minimum exposure time value. and an exposure mode setting unit that sets the long exposure time and the short exposure time based on the contrast value of the image obtained by performing temporary imaging of the workpiece while sequentially changing the length of the image. measuring machine. The image measuring machine according to claim 1,
The exposure mode setting unit sets the exposure time of the image having the contrast value equal to or greater than a predetermined reference value and the longest exposure time among the plurality of images obtained by the temporary imaging as the long exposure time, An image measuring instrument, wherein the exposure time of an image having a contrast value equal to or greater than a predetermined reference value and the shortest exposure time is set as the short exposure time. The image measuring machine according to claim 2,
The exposure mode setting unit has a long exposure mode setting unit and a short exposure mode setting unit,
The long-time exposure mode setting unit detects the contrast value of images captured with successively shorter exposure times from the maximum exposure time, and sets the exposure time of the image for which the obtained contrast value is equal to or greater than the reference value. Set as long exposure time,
The short-time exposure mode setting unit detects the contrast value of images captured with successively longer exposure times from the minimum exposure time value, and sets the exposure time of the image for which the obtained contrast value is equal to or greater than the reference value. An image measuring machine characterized in that it is set as a short exposure time. Using an image measuring machine having a camera for imaging a workpiece, an imaging control section for controlling the imaging operation of the camera, and an image processing section for processing an image signal from the camera,
First, as a time-division imaging setting step of setting a long exposure time and a short exposure time when imaging with the camera, the imaging control unit performs contrast detection for detecting the contrast value of the image of the work imaged with the camera. and, while changing the temporary exposure time from a predetermined maximum exposure time to successively shorter or from a predetermined exposure time minimum value to successively longer, the workpiece is provisionally imaged, and the temporary exposure time is changed based on the contrast value of the image obtained. an exposure mode setting step of setting the exposure time and the short exposure time;
Next, the imaging control unit executes a time-division imaging control step of causing the cameras to perform imaging operations in the long exposure time and the short exposure time, respectively;
Subsequently, the image processing unit generates a composite image of the workpiece from the long exposure image of the workpiece captured with the long exposure time and the short exposure image of the workpiece captured with the short exposure time. An image measurement method characterized by executing an image synthesizing step to generate. In the image measurement method according to claim 4,
In the exposure mode setting step, among the plurality of images obtained by the temporary imaging , the exposure time of the image having the contrast value equal to or greater than a predetermined reference value and the longest exposure time is set as the long exposure time; An image measuring method, wherein an exposure time of an image having a contrast value equal to or greater than a predetermined reference value and having the shortest exposure time is set as the short exposure time. In the image measurement method according to claim 5,
The exposure mode setting step includes a long exposure mode setting step and a short exposure mode setting step,
In the long-time exposure mode setting step, the contrast value is detected for images captured with successively shorter exposure times from the maximum exposure time, and the exposure time of the image for which the obtained contrast value is equal to or greater than the reference value is Set as long exposure time,
In the short-time exposure mode setting step, the contrast value is detected for images captured with successively longer exposure times from the minimum exposure time value, and the exposure time of the image for which the obtained contrast value is equal to or greater than the reference value is An image measuring method characterized by setting a short exposure time.

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