WO2018061430A1 - Measurement apparatus, measurement method, measurement program, and recording medium - Google Patents

Abstract

Provided are a measurement apparatus and a measurement method that are capable of suitably calculating reference information indicating the level of reliability of a measurement value obtained through a measurement. A measurement apparatus (1) that measures a measurement value according to a measurement point designated on an imaged image is provided with a reference information calculation unit (11) that calculates reference information indicating the level of reliability of the measurement value such that the level of reliability is set higher as the degree of focusing of the measurement point in the imaged image becomes higher.

Description

Measuring device, measuring method, measuring program, and recording medium

One embodiment of the present invention relates to a measurement device, a measurement method, a measurement program, and a recording medium.

As an example of a system for measuring the three-dimensional position or the like of a subject, a system for measuring a three-dimensional position or the like of a subject by specifying a measurement point on a captured image obtained by capturing the subject and acquiring position information of the measurement point. is there. In Patent Document 1, two measurement points, a measurement start position and a measurement end position, are specified in a captured image captured by an image capturing apparatus, and the length in real space between the two points from the three-dimensional position ( An imaging apparatus for calculating (distance) is described.

Japanese Patent Publication “Japanese Patent Laid-Open No. 2011-232330 (published on November 17, 2011)”

However, in the prior art, information indicating how reliable the calculated measurement value is is insufficient. For example, Patent Document 1 discloses only obtaining a relative error caused by camera movement.

One aspect of the present invention has been made in view of the above points, and an object thereof is to provide a measurement apparatus and a measurement method that can suitably calculate reference information indicating the reliability of measured values. There is.

In order to solve the above problems, a measuring device according to one embodiment of the present invention includes:
A measurement device that measures a measurement value according to a measurement point specified on a captured image,
A calculation unit for calculating reference information indicating the reliability of the measurement value,
The calculation unit calculates the reference information such that the higher the degree of focusing of the measurement point in the captured image, the higher the reliability.

In order to solve the above problem, a measurement method according to one embodiment of the present invention includes:
A measurement method for measuring a measurement value according to a measurement point designated on a captured image,
Including a calculation step of calculating reference information indicating the reliability of the measurement value,
In the calculation step, the reference information is calculated such that the higher the degree of focusing of the measurement point on the captured image, the higher the reliability.

According to one aspect of the present invention, it is possible to suitably calculate reference information indicating the reliability of the measured value.

It is a block diagram which shows the structure of the measuring device which is one Embodiment of this invention. It is a figure which shows an example of the image by which the to-be-photographed object which is a measuring object of the measuring device shown in FIG. 1 was imaged. It is a flowchart which shows an example of the process which the measuring device shown in FIG. 1 performs. It is a figure which shows an example of the relationship between the distance from an imaging device which images the to-be-photographed object which is a measuring object of the measuring device shown in FIG. 1, a focus position, and a depth of field. It is a figure which shows an example of the display method on the display apparatus of the information output from the measuring device shown in FIG. It is a figure which shows an example of the display method on the display apparatus of the information output from the measuring device shown in FIG. It is a block diagram which shows the structure of the measuring device which is other embodiment of this invention. It is a flowchart which shows an example of the process which the measuring device shown in FIG. 7 performs. It is a figure which shows an example of the image by which the to-be-photographed object which is a measuring object of the measuring device shown in FIG. 7 was imaged. It is a figure which shows an example of the graph regarding the luminance value change used for the amount of blur measurement in the measuring apparatus shown in FIG. It is a block diagram which shows the structure of the measuring device which is other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the configuration described in each embodiment is merely an illustrative example, and is not intended to limit the scope of the embodiment of the present invention, unless specifically limited. Each figure is for explanation, and may differ from the actual one.

Embodiment 1
Regarding the measurement of the three-dimensional position of a subject, there are cases where high measurement accuracy is required or there is no problem with low measurement accuracy, depending on the application and user requirements. Therefore, when a measurement result is obtained with a certain accuracy, the judgment on whether to adopt the result differs depending on the user. Therefore, it is desirable that the measurement apparatus can calculate information such as accuracy and reliability of the measurement result.

Here, according to the inventors' original knowledge, when measuring a three-dimensional position of a subject by specifying a measurement point on a captured image of the subject, whether the measurement point is in focus, that is, measurement Whether the position of the point is blurred affects the accuracy of the measurement and the reliability of the result. For example, if the characteristics of the subject become unclear due to blurring, a user's specification error may occur, so the reliability of the measurement result is low. In addition, when calculating distance information from a captured image by the stereo method, the accuracy and reliability of the measurement result are low because the calculation accuracy of the distance information may be reduced due to blurring. Since the stereo system is a known technique, a detailed description is omitted.

Therefore, a measurement apparatus according to an aspect of the present invention is a measurement apparatus that measures a measurement value according to a measurement point specified on a captured image, and calculates reference information indicating the reliability of the measurement value. And the calculation unit calculates the reference information such that the higher the degree of focusing of the measurement point in the captured image, the higher the reliability.

As a result, the measurement device has a low degree of focus of the measurement point in the captured image, low reliability of the measurement value according to the measurement point specified on the blurred captured image, and the alignment of the measurement point in the captured image. Shows the reliability of the measured value by calculating the reference information so that the reliability of the measured value corresponding to the specified measurement point on the captured image that is high in focus and not blurred is high Reference information can be suitably calculated.

In the present specification, the reliability of the measurement value is an index indicating how much the user can trust the measurement value, and includes an index indicating the accuracy of the measurement value or an index indicating an error of the measurement value. The reference information may be information indicating the reliability of the measurement value, and may be information indicating the reliability of the measurement value stepwise or continuously.

Also, the blur of the captured image changes mainly depending on the performance of the imaging device and the focus position and aperture setting at the time of imaging. Since the depth of field representing the in-focus range is a range before and after the focal position, the blur increases when the position of the measurement point is away from the focal position and outside the depth of field. Therefore, it can be said that the reliability of the measurement result changes depending on the positional relationship between the measurement point and the focal position or the depth of field.

Therefore, in the measurement apparatus according to one aspect of the present invention, the reliability of the measurement value is calculated based on the position information and focus information of the measurement point. Since the degree of focus of the measurement point in the captured image can be determined based on the position information and focus information of the measurement point, reference information indicating the reliability of the measurement value can be suitably calculated. Hereinafter, a measurement apparatus and a measurement method according to an embodiment (Embodiment 1) of the present invention will be described with reference to FIGS.

FIG. 1 is a block diagram showing the configuration of the measuring apparatus 1 according to this embodiment. As shown in FIG. 1, the measurement apparatus 1 according to the present embodiment includes a position information acquisition unit 10 and a reference information calculation unit 11 (calculation unit).

The measurement apparatus 1 of this embodiment can be realized by software processing by a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field Programmable Gate Array). It can also be realized by hardware processing according to.

The measurement device 1 receives measurement point information, distance information, and focus information, which will be described later, from the outside of the measurement device 1 and outputs measurement values and reference information corresponding to the measurement points specified on the captured image.

In the following description, it is assumed that the user designates measurement points on the captured image in advance using an input device or a display device other than the measurement device 1. For example, it is assumed that a measurement point is designated on a captured image as shown in FIG. FIG. 2 shows the subject 20 and one measurement point 21 designated by the user.

In the present embodiment, a mode in which reference information is calculated for the measurement value of one measurement point 21 (FIG. 2) will be described. The measurement value at one measurement point is a three-dimensional position at a certain position in the real space corresponding to one measurement point. However, the embodiment of the present invention also includes an aspect for calculating reference information of measurement values at two or more measurement points. Here, the measurement values of two or more measurement points include, for example, the length (distance) between positions in the real space corresponding to each measurement point and the three-dimensional positions of a plurality of measurement points. All measurement values that can be measured by are included. For example, in addition to the examples given above, the area, angle, volume, or distance of the object such as height and width, the perimeter of the object, the diameter of the object, the length of the arc, the length of the string, etc. and so on. And calculating reference information which shows the reliability using these as measurement values is also included in the embodiment of the present invention.

Hereinafter, measurement point information, distance information, and focus information input from the outside of the measurement apparatus 1 will be described.

The measurement point information is a coordinate value in the two-dimensional coordinate system of the captured image, and represents the position of the measurement point desired by the user on the captured image. For example, the measurement point is provided on a display device and an input device (not shown) outside the measurement device 1, and the user operates the input device while checking the captured image displayed on the display device. It is obtained by specifying the position of.

Although the measurement device 1 of the present embodiment is configured to input measurement point information from the outside, the measurement device 1 includes a display device and an input device, and the captured image is displayed on the display device and designated by the input device. By doing so, you may make it acquire measurement point information. In the case where the measuring device 1 includes a display device, not only the captured image is displayed, but also output results such as measured values and reference information may be displayed.

The input device is an input device such as a mouse or a keyboard. The display device is a display device having, for example, a liquid crystal element and an organic EL (Electro Luminescence) as a pixel, and is a television display, a PC (Personal Computer) monitor, or a display of a mobile terminal such as a smartphone or a tablet terminal. is there.

It should be noted that the input device and the display device may be a touch panel (for example, a touch panel of a resistance film type or a capacitance type) in which these are integrated. The measurement point information is not limited to the information acquired by the above method, and may be information acquired by any method as long as it is a measurement point on the image desired by the user. In addition, when an object to be measured is determined in advance, a measurement point can be automatically set. For example, by registering representative image data of a subject to be measured and searching for representative image data in the acquired captured image, measurement point information that is the position of the measurement point is automatically acquired. Also good.

Focus information is information on the focus position or information on the depth of field when a captured image in which a measurement point is specified is captured. The focal position information is information representing a focused position when a captured image in which a measurement point is specified is captured by the imaging apparatus. The focal position information includes, for example, positional information of the captured image in a two-dimensional coordinate system and a distance value from the imaging device to the focal position. When the input focus position information is only the position information of the two-dimensional coordinate system of the captured image, the distance value of the focus position corresponding to the position information of the two-dimensional coordinate system is acquired based on the distance information described later. .

The information on the depth of field is information indicating a distance range (focusing range) in which the focal points spreading in front and behind the focal position are in focus. The information on the depth of field includes, for example, a distance value from the imaging device to the front end of the focusing range and a distance value from the imaging device to the rear end of the focusing range.

Note that the measurement apparatus 1 of the present embodiment is configured to input focus information from the outside. However, the measurement apparatus 1 includes an imaging device, and an image is captured by the imaging device. You may make it acquire the information of depth. In this case, since it is necessary to specify a measurement point on an image captured by the image capturing apparatus, it is preferable that the measurement apparatus 1 includes the display device and the input device as described above. The imaging apparatus includes, for example, an optical system such as a lens module, an image sensor such as a CCD (Charge-Coupled Device) and a CMOS (Complementary Metal-Oxide Semiconductor), an analog signal processing unit, and an A / D (Analog / Digital) conversion unit. The signal from the image sensor is output as an image.

The distance information is a distance value from the imaging device that captured the image to the subject, and includes at least a distance value from the imaging device to the subject at the measurement point position. The distance information is acquired by a distance measuring device using a known distance measuring method. Examples of the distance measurement method include a method using infrared rays represented by a TOF (TimeＴＯOf Flight) method, a stereo method, and the like.

In the measurement apparatus 1 of the present embodiment, distance information is input from the outside, but the distance measurement apparatus may be included in the measurement apparatus 1. In the case of a configuration including a distance measuring device, the configuration includes the imaging device, the input device, and the display device as described above, and the distance information corresponding to the image of the imaging device is acquired, thereby being designated on the image. The distance information of the measurement point can be acquired. Furthermore, when acquiring distance information by the stereo method, a stereo pair image is input from the outside, or two image pickup devices are provided in the measurement device 1 to pick up a stereo pair image. Distance information can be calculated based on the image.

The position information acquisition unit 10 acquires the position information of the measurement point based on the measurement point information and the distance information. Details of the position information will be described later. When the position information acquisition unit 10 calculates three-dimensional information of measurement points as position information, camera parameter information is input to the measurement apparatus 1. The camera parameter is information such as the resolution of the image for which the measurement point is designated and the focal length of the imaging device that captured the image. The camera parameters may be input by being included in the measurement point information or distance information.

The reference information calculation unit 11 calculates reference information regarding the measurement point based on the focus information and the position information. Details of the reference information will be described later.

[Measurement method]
Below, with reference to FIG. 3, the flow of the measurement process using the measuring device 1 is demonstrated. FIG. 3 is a flowchart illustrating an example of processing of the measurement apparatus 1.

(Process flow)
<Step S101>
In step S101 illustrated in FIG. 3, measurement point information, distance information, and focus information are input to the measurement apparatus 1 from the outside.

<Step S102>
In step S102 shown in FIG. 3, the position information acquisition unit 10 acquires the position information of the measurement point based on the measurement point information and the distance information (acquisition step). The position information is provided to the reference information calculation unit 11, and the process proceeds to step S103. Details of the processing in step S102 will be described later.

<Step S103>
In step S103 illustrated in FIG. 3, reference information indicating the reliability of the measurement value is calculated by the reference information calculation unit 11 based on the focus information input in step S101 and the position information acquired in step S102. (Calculation step). Details of the processing in step S103 will be described later.

<Step S104>
In step S104 shown in FIG. 3, the position information (measurement value) acquired in step S102 and the reference information calculated in step S103 are output to the outside of the measurement apparatus 1.

By the above procedure, the measuring apparatus 1 according to the present embodiment outputs the measurement values and reference information of the measurement points.

In the following, details of the information and processing contents handled in each processing step will be described.

(Step S102 position information)
In step S102, the position information acquisition unit 10 acquires position information based on the measurement point information and the distance information. As position information, position information (hereinafter also referred to as image coordinates) of a two-dimensional coordinate of a captured image of a measurement point input as measurement point information and a distance value input as distance information are set. The distance value is a distance from an imaging device (an imaging unit having an imaging element) that captures an image to a subject, and is a value in the optical axis direction of the imaging device.

Also, the position information acquisition unit 10 calculates the three-dimensional coordinates of the measurement points based on the camera parameters input to the measurement apparatus 1 and the image coordinates and distance values of the measurement points set as position information. When the image coordinates of the measurement point are (u, v) and the distance value is Z, the three-dimensional coordinates (Xp, Yp, Zp) of the measurement point are calculated by the equation (1).

Here, f shown in Expression (1) is the focal length of the imaging apparatus, w is the horizontal resolution of the image, and h is the vertical resolution of the image. The image coordinates (u, v) are coordinates when the upper left corner of the image is the coordinate (0, 0) and the lower right corner is the coordinate (w-1, h-1). In addition, the calculated three-dimensional coordinates of the measurement points are represented by a three-dimensional coordinate system based on the imaging device.

As described above, the position information acquisition unit 10 acquires the image coordinates and distance value of the measurement point from the measurement point information and distance information input from the outside. Furthermore, the position information acquisition unit 10 calculates the three-dimensional coordinates of the measurement points based on the acquired information and camera parameters. The acquired information (image coordinates and distance values of measurement points) is provided as position information to the reference information calculation unit 11 at the subsequent stage, and the calculated three-dimensional coordinates of the measurement points are used as measurement values in the present embodiment. Output to the outside of the measuring device 1.

(Step S103 Reference Information)
In step S <b> 103, the reference information calculation unit 11 calculates reference information indicating the reliability of the measurement value based on the focus information input from the outside and the position information of the measurement point input from the position information acquisition unit 10. .

Here, taking the image shown in FIG. 2 as an example, a diagram showing the relationship between the distance from the imaging device to the subject, the focal position, and the depth of field is shown in FIG. FIG. 4 is a view of the subject 20 shown in FIG. 2 and the imaging device 4 (imaging unit) used for imaging. The subject 20 shows the position of the measurement point 21. FIG. 4 shows the position of the measurement point 22 not shown in FIG. Further, FIG. 4 shows the distance Dp of the measurement point position, the distance Dfc of the focal position, the distance Dn of the front depth of field position, the distance Df of the rear depth of field position, and the range of the depth of field. ing. In FIG. 4, the position of the measurement point 21 is a position in front of the focal position Dfc inside the depth of field.

If the subject at the measurement point exists outside the depth of field, the measurement accuracy is low and the reliability is low due to the influence of blur. Therefore, the reference information calculation unit 11 calculates information about whether the measurement point position is inside or outside the depth of field based on the distance between the measurement point position and the depth of field, and uses the information as reference information. . In the case of the measurement point 21 in FIG. 4, information indicating that it is inside the depth of field, that is, information indicating that the reliability of the measurement point 21 is high is output as reference information. On the other hand, in FIG. 4, when the measurement point is the measurement point 22, the measurement point is outside the depth of field, and therefore information indicating outside the depth of field as reference information, that is, the reliability of the measurement point 22 is low. Information indicating that is output. In this way, the user can determine whether or not a blurred position has been designated based on information indicating whether the measurement point position is inside or outside the depth of field. That is, it is possible to easily determine whether or not a position with low reliability (measurement accuracy) is designated.

Here, in the present embodiment, the method of outputting either the measurement point outside the depth of field or within the depth of field is described. However, the measurement point is outside the depth of field or the depth of field. The user can check the reliability of the measurement result even in the method of outputting any one of the above. In other words, when the reference information is output only when the measurement point position is outside the depth of field, if the reference information is not output, the measurement point position is located within the depth of field, that is, the measurement value The user can confirm that the reliability is high.

Also, as the position is farther from the focal position, the amount of blur increases, the measurement accuracy decreases, and the reliability decreases. Therefore, the reference information calculation unit 11 calculates the absolute value (distance interval) of the difference between the measurement point position and the focus position, and uses the information indicating that the reliability of the measurement value is lower as the distance interval is larger as reference information. When output, it is preferable because the user can confirm the degree of decrease in the reliability of the measurement value. For example, set a stepped range such as reliability `` low, medium, high '' according to how the depth of field extends, determine which range the distance interval value is, and Information indicating the reliability is used as reference information. In this case, a stepwise range may be defined by providing a threshold value in advance. The reference information may be the distance value itself of the distance interval, but setting the range as described above is preferable because the user can easily determine the measurement result.

In the above description, the distance interval is the difference between the measurement point position and the focus position. However, the distance interval may be acquired based on the difference between the measurement point position and the position of the front depth of field or the position of the rear depth of field. .

Furthermore, when the measurement point is located outside the depth of field, the relationship with the depth of field, that is, the measurement point is located on the side farther than or closer to the depth of field range. Additional information, such as whether or not it is, may be acquired and output. This is because the depth of field differs between the near view and the distant view, which is effective for user confirmation.

Further, the reference information is not limited to the above, and any information may be used as long as it can assist the determination when the user determines whether to adopt the measurement point or the measurement value. Absent.

As described above, the reference information calculation unit 11 calculates the reference information based on the focus information and the position information of the measurement point. Based on the reference information, the user can easily determine whether or not the measurement result is reliable and further whether or not the measurement result is adopted.

It should be noted that various types of information may be displayed on the display device as a configuration including a display device inside or outside the measuring device 1. When it is set as the structure with which the inside of the measuring device 1 is provided, you may make it add the display part which is not illustrated in FIG. In addition, a display apparatus and a display part are synonymous. For example, display is performed on the display device as shown in FIGS.

5 and 6, an image in which the subject 20 is captured is displayed on the display device in the same manner as the image shown in FIG.

In FIG. 5, the position of the measurement point 21 designated on the image on the display device 5 (display unit) is shown superimposed on the image with a cross symbol (sign). In addition, the mark which shows the position of the measurement point 21 is not limited to this. Further, a distance value from the imaging apparatus to the subject at the position of the measurement point 21 is shown as a measurement value at the display position 51, and a reliability of the measurement value as reference information is shown at the display position 52.

In FIG. 6, the positions of the measurement points 61 and 62 designated on the image displayed on the display device 6 (display unit) are superimposed on the image by symbols (signs), and each measurement is performed from the imaging device as a measurement value. The distance value to the subject at the point position is superimposed and displayed near the measurement point. In FIG. 6, the reliability of the measurement value as reference information is represented by the shape of a symbol (sign), and the measurement point 61 with high reliability is indicated by a circle, and the measurement point 62 with low reliability is indicated by a cross. ing. In addition, each label | marker which shows reliability is not limited to this. The measurement point 61 is the same position as the measurement point 21 shown in FIG. 2. As shown in FIG. 4, since the measurement point 61 is a position inside the depth of field, it is determined that the reliability is high. Yes. On the contrary, since the measurement point 62 is a position on the far side of the subject 20 and a position outside the depth of field, it is determined that the reliability is low.

By performing display on the display device as described above, the user can easily confirm the measurement point position, the measurement value of the measurement point, and the reference information together with the image. It is.

The display method is not limited to the above, and the reference information may be represented by changes in the brightness, saturation, hue, etc. of the sign, or may be represented by changes in the brightness, saturation, hue, or font of the character of the measurement value. May be. Or you may make it show by the method of making the measurement point with high reliability conspicuous by changing the brightness | luminance, saturation, and hue of an image.

As described above, the display device (display unit) displays the reference information in association with the measurement value or changes the display method of the measurement value according to the reference information, so that the user can obtain the measurement value and the reference information. Can be easily confirmed, which is preferable because convenience is improved. In particular, like the display device 6 shown in FIG. 6, the display device (display unit) displays the captured image and displays a marker indicating the position of the measurement point superimposed on the captured image, according to the reference information. By changing the display method of the sign, the user can easily confirm the measurement value and the reference information together with the captured image, which is preferable because convenience is improved.

[Modification 1]
In the measurement apparatus 1 described above, the position information acquisition unit 10 measures the measurement value by calculating the three-dimensional position of one measurement point 21. However, the present embodiment is not limited to this, and a measurement value calculation unit (not shown) refers to a three-dimensional position of one or more measurement points calculated by the position information acquisition unit 10 to determine distance, area, angle, volume. Or, it is configured to measure the measured value by calculating the distance of the object such as height and width, the perimeter and diameter of the object, the length of the arc, the length of the irregular shape such as the string, etc. It may be.

[Modification 2]
The reference information calculation unit 11 described above uses the position information of the measurement point input from the position information acquisition unit 10 for the calculation of the reference information as described in step S103. However, when only distance information of the measurement point can be acquired from the outside with respect to the distance information, the reference information calculation unit 11 uses only information input from the outside without acquiring information from the position information acquisition unit 10. Reference information may be calculated. However, when the distance information input from the outside is not only the distance information of the measurement point but also information about each position (each pixel) of the entire image, the position information acquisition unit 10 determines the distance information of the entire image The distance information of the measurement point is extracted (step S102), the reference information acquisition unit 11 acquires the extracted distance information, and calculates the reference information as described in step S103.

In addition, when the distance information input from the outside is the distance from the center of the lens included in the imaging device to the subject, the processing (such as an error) is corrected to the distance from the tip of the lens to the subject. The position information acquisition unit 10 may first perform processing for subtracting the offset. In that case, the information acquired from the position information acquisition unit 10 is required for the calculation of the reference information by the reference information acquisition unit 11.

[Embodiment 2]
In the measurement apparatus 1 described in the first embodiment, the reference information is calculated in consideration of blur caused by the focal position, the depth of field, and the like. However, in addition to the focus information, the image blur may be caused by the characteristics of the optical system of the imaging apparatus, particularly the lens, or may be caused by camera shake at the time of shooting or motion blur of the subject. Therefore, the measurement device 7 according to the second embodiment calculates reference information indicating the reliability of the measurement value regardless of the cause of the blur by calculating the blur amount from the image.

Hereinafter, the second embodiment will be described with reference to FIGS.

FIG. 7 is a block diagram showing the configuration of the measuring device 7 of the second embodiment. As illustrated in FIG. 7, the measurement device 7 according to the second embodiment adds a blur amount calculation unit 70 to the configuration of the measurement device 1 illustrated in FIG. 1, and the reference information calculation unit 11 replaces the reference information calculation unit 71. has been edited. The position information acquisition unit 10 is a processing unit similar to that shown in the measurement apparatus 1 shown in FIG. 1, and the processing content is also the same, so the description thereof will be omitted below.

Measurement point information, distance information, focus information, and image information (luminance information) are input from the outside to the measurement device 7 according to the second embodiment, and measurement values and reference information of measurement points specified on the captured image are output. To do.

Here, the reference information calculation unit 71 described later can calculate the reference information even when focus information is not input from the outside. Therefore, a configuration in which focus information is not input to the measurement device 7 may be employed.

Note that measurement point information, distance information, and focus information are the same as the information input to the measurement apparatus 1 described in the first embodiment, and will not be described.

The image information is image data in which a measurement point position that is measurement point information is designated. Hereinafter, a method of calculating the blur amount based on the luminance information of each pixel of the image will be described assuming that a grayscale image is input as the image information. However, the image information is not limited to this, and a configuration in which a color image is input may be used. When a color image is input, the amount of blur is calculated based on the color information of each pixel expressed in a general color space such as RGB or CMY. In this case, the amount of blur may be calculated by converting color information into luminance information by a known method, or replacing any information in the color information with luminance information. When the color information is replaced with the luminance information, if the color information is information in the RGB color space, any value of the R, G, and B components may be used as the luminance information as it is.

The blur amount calculation unit 70 calculates the blur amount at the measurement point position based on the measurement point information and the image information. Details of the blur amount calculation method will be described later.

The reference information calculation unit 71 calculates reference information indicating the reliability of the measurement value based on the blur amount calculated by the blur amount calculation unit 70. When focus information is input to the measurement device 7, reference information is calculated based on the amount of blur, the focus information, and the position information acquired by the position information acquisition unit 10. Details of the reference information will be described later.

[Measurement method]
Below, with reference to FIG. 8, the flow of the measurement process using the measurement apparatus 7 of this Embodiment 2 is demonstrated. FIG. 8 is a flowchart showing an example of processing of the measuring device 7.

(Process flow)
<Step S201>
In step S <b> 201 shown in FIG. 8, measurement point information, distance information, focus information, and image information are input to the measurement device 7 from the outside.

<Step S202>
In step S202 illustrated in FIG. 8, the blur amount calculation unit 70 calculates the blur amount at the measurement point position based on the measurement point information and the image information. The blur amount is output to the reference information calculation unit 71, and the process proceeds to step S203. Details of the processing in step S202 will be described later.

<Step S203>
In step S203 illustrated in FIG. 8, the position information of the measurement point is acquired by the position information acquisition unit 10 based on the measurement point information and the distance information. The position information is output to the reference information calculation unit 71, and the process proceeds to step S203. Note that the process in step S203 is the same as the process in step S102 of the measurement apparatus 1 described in the first embodiment, and a detailed description thereof will be omitted.

<Step S204>
In step S204 shown in FIG. 8, based on the blur amount calculated in step S202, or based on the blur amount calculated in step S202, the focus information, and the position information acquired in step S202. The information calculation unit 71 calculates reference information indicating the reliability of the measurement value. Details of the processing in step S204 will be described later.

<Step S205>
In step S205 shown in FIG. 8, the position information (measurement value) acquired in step S203 and the reference information calculated in step S204 are output to the outside of the measurement device 7.

By the above procedure, the measurement device 7 of the second embodiment outputs the measurement value of the measurement point and the reference information to the outside.

In the following, details of the information and processing contents handled in each processing step will be described.

(Step S202 amount of blur)
In step S202, the blur amount calculation unit 70 calculates the blur amount at the measurement point position based on the measurement point information and the image information.

A method of calculating the blur amount will be described with reference to FIGS. 9 and 10.

FIG. 9 shows a subject 90 and a measurement point 91 designated at the edge position of the subject 90.

(A) and (b) in FIG. 10 are graphs showing changes in luminance values in a predetermined range in the horizontal direction centered on the measurement point 91. The luminance value Job of the subject 90 and the luminance of the background, respectively. The value Ybg, the edge position of the measurement point 91, and the range representing the blur amount are shown. (A) in FIG. 10 represents a state where the edge is clear when the amount of blur is small, and (b) in FIG. 10 represents a state where the edge when the amount of blur is large. As shown in (b) of FIG. 10, the blur value is larger as the luminance value at the edge position is gradually changed.

The blur amount calculation unit 70 uses the number of pixels between the start point and the end point at which the luminance gradient changes as shown in FIGS. 10A and 10B (hereinafter referred to as the blur pixel number) as the blur amount. calculate. The predetermined range for confirming the change in the luminance gradient is set, for example, as a range of 100 pixels before and after the pixel at the measurement point position. The number of pixels in the predetermined range is set to a minimum range in which the luminance gradient can be sufficiently confirmed according to the resolution of the image and the size of the assumed measurement target object in the image.

9 and 10, the blur amount calculation unit 70 detects the edge of the measurement point position, acquires the luminance value of a pixel in a predetermined range in the direction perpendicular to the edge direction, and changes the luminance value. The amount of blur is calculated from the state. Edge detection can be performed by a known image processing technique such as a technique using a Sobel filter. The blur amount may be calculated by detecting an edge around the measurement point position and calculating the blur amount at that position. Alternatively, the luminance value change may be confirmed and calculated in various directions such as horizontal, vertical, and diagonal with the measurement point position as the center.

In the above description, the blur amount calculation unit 70 calculates the blur amount based on the luminance value of the image, but the embodiment of the present invention is not limited to this. For example, in the case of a color image, the blur amount may be calculated using the R, G, and B components of each pixel as described above.

The blur amount may be calculated as the blur pixel number itself as described above. However, the blur amount may be determined in several stages such as “large, medium, small” by a preset threshold value of the pixel number. It doesn't matter. The blur amount calculation method is not limited to the above method, and any method may be used as long as the blur amount at the measurement point position of the image can be calculated. For example, the amount of blur can be calculated from the characteristics of an optical system that captures an image, or a value obtained by calculating or measuring the relationship between the amount of blur and the distance from the imaging device to the subject in advance can be used. Alternatively, when the subject of the captured image is known in advance, the blur amount may be calculated based on the difference between the reference image of the subject and the captured image.

Note that when the measurement point position is flat and there are no characteristic points or edges around it, and the change in the luminance value is small, the blur amount cannot be calculated as described above. In such a case, the blur amount calculation unit 70 outputs information that the measurement point position is a flat region to the reference information calculation unit 71 at the subsequent stage.

As described above, the blur amount calculation unit 70 calculates the blur amount at the measurement point position based on the measurement point information and the image information, and outputs the blur amount information to the reference information calculation unit 71 in the subsequent stage. Since the blur amount calculation unit 70 calculates the blur amount from the image information, for example, when there is no focus information or when the characteristics of the optical system and the setting of the imaging device are unknown, the reference information calculation unit 71 in the latter stage is blurred. Reference information can be calculated based on the amount.

(Step S204 Reference Information)
In step S <b> 204, the reference information calculation unit 71 calculates reference information based on the blur amount calculated by the blur amount calculation unit 70. When focus information is input to the measurement device 7, the reference information calculation unit 71 obtains reference information based on the position information acquired by the focus information and the position information acquisition unit 10 in addition to the amount of blur. get.

The greater the amount of blur, the lower the reliability of the measured value. Therefore, the reference information calculation unit 71 outputs information that the reliability of the measurement value is lower as the input blur amount is larger as reference information. When the information on the amount of blur is information of several stages such as the amount of blur “large, medium, small”, information on the reliability “low, medium, high” is used as reference information accordingly. Note that the reference information is not defined by words, but may be a numerical value such as a reliability of 30%. In this case, by setting in advance the blur amounts that will give a reliability of 100% and 0%. The reliability corresponding to the calculated amount of blur can be acquired. For example, when the blur width (number of pixels) shown in FIG. 10 is less than 10% of the luminance difference before and after the edge, the reliability is set to 100%. Note that the magnitude of the blur amount may be defined as an error, and information that the error is larger as the blur amount is larger may be used as reference information. If the information on the blur amount is information that the measurement point position is a flat region, information indicating that the blur amount cannot be calculated or the reliability cannot be calculated is output as reference information. Alternatively, since the flat region has no features and is likely to cause a specification error by the user, information indicating low reliability is used as reference information. In particular, when the distance information input to the measuring device 7 is acquired based on the stereo method, the distance measurement accuracy of a flat region is low, and therefore it is preferable to use the information that the reliability is low as reference information. is there.

[Embodiment 3]
In the above-described second embodiment, the aspect in which the focus information is not input to the measurement device 7 has been described. However, as in the third embodiment, the focus information may be input to the measurement device 7 in the second embodiment. . Hereinafter, the third embodiment will be described.

When the focus information is input to the measurement device 7 of Embodiment 2, the reference information calculation unit 71 calculates the reference information based on the blur amount as described above and sets it as the first reference information. Further, similar to the process in step S103 of the measurement apparatus 1 described in the first embodiment, the reference information based on the measurement point information and the focus information is calculated and used as the second reference information. The reference information calculation unit 71 uses both the first reference information and the second reference information as final reference information. For example, information such as the measurement point position is outside the depth of field range and the reliability is 10%. Is output. Alternatively, based on the first reference information and the second reference information, a comprehensive reliability is acquired and used as reference information. For example, even if the measurement point position is outside the depth of field and far from the focus position, if the blur amount is small, information indicating that the reliability is high is output as reference information. Thus, by acquiring reference information from two criteria, it is possible to obtain reference information with higher accuracy.

Here, when the position on the subject having a blurred pattern or shape is used as the measurement point, it is difficult to determine whether or not the blur actually occurs from only the blur amount. However, if both the first reference information and the second reference information are calculated, it is possible to determine the amount of blur by determining the presence or absence of blur due to the focus information. For example, if reference information is output that the measurement point position is inside the depth of field and the amount of blur is large, the blur is not caused by the focus position or depth of field but by the pattern or shape of the subject. Alternatively, it can be determined that the blur is caused by camera shake or motion blur. With this information, the user can take measures such as redesigning another measurement point position with high reliability, or re-taking an image without the influence of camera shake or the like.

As described above, the reference information calculation unit 71 acquires the first reference information based on the blur amount calculated from the image information and the second reference information based on the position information and the focus information of the measurement point to obtain the reference information. Output. As a result, it is possible to acquire reliability information corresponding to the amount of blur regardless of the cause of the blur. In addition, it is possible to know highly accurate reference information acquired from the two standards of the first reference information and the second reference information. Therefore, the user can measure by determining whether the measurement result is acceptable based on the reference information. Further, the user can determine whether the measurement point position can be measured with appropriate reliability, and can take measures such as redesignating another measurement point position.

[Embodiment 4]
In the measurement apparatus 7 according to the second embodiment described above, the reference information is calculated based on the magnitude of the blur amount calculated by the blur amount calculation unit 70, but the embodiment of the present invention is not limited to this. Instead, the reference information calculation unit 71 may calculate the measurement error based on the blur amount calculated by the blur amount calculation unit 70 and use it as reference information. As described above, the measurement value reliability includes a measurement error.

This example will be described below.

The length Lpix of the subject captured in one pixel of the image is expressed by Expression (2), where Z is the distance from the imaging device to the subject.

Here, f shown in Expression (2) is a focal length of the imaging apparatus, and p is a pixel pitch of an imaging element included in the imaging apparatus.

When a subject with a distance Z is designated as a measurement point on the image and the measurement point position is shifted by one pixel in the horizontal or vertical direction, the three-dimensional position is shifted in the horizontal or vertical direction by Lpix. Become. That is, an error occurs in the measured value by the amount of Lpix. That is, Lpix represents a measurement error per pixel at the distance Z.

As described in step S202, the blur amount calculation unit 70 calculates the number of blur pixels as the blur amount of the measurement point. When a subject with a distance Z is designated as a measurement point on the image and the number of blurred pixels at the measurement point is Pb, the number of blurred pixels spreading in one direction from the measurement point position is Pb / 2. The maximum shift amount of the measurement point position caused by the influence is Pb / 2. At this time, the measurement error Eres can be calculated by Equation (3).

The reference information calculation unit 71 calculates a measurement error from the blur amount of the measurement point based on the formulas (2) and (3), and uses it as reference information. As described above, the reference information calculation unit 71 calculates the measurement error as reference information, so that the user can check the measurement error included in the measurement result.

Note that the above measurement error is a measurement error that takes into account a user-specified error caused by the influence of blur, but the calculation method of the measurement error is not limited to this. For example, when distance information is acquired based on a stereo method, in the stereo method, a parallax value is calculated based on a stereo pair image, and a distance value is calculated based on the parallax value. An error may occur due to blurring when calculating the parallax, and the parallax value calculation error becomes a measurement error. Therefore, the reference information calculation unit 71 may calculate the measurement error in the depth direction from the calculation error of the parallax value that may occur according to the amount of blur, and may use it as reference information. Whereas the measurement error due to the user-specified error is an error in the horizontal direction (X-axis direction) or vertical direction (Y-axis direction) in the three-dimensional coordinate system of the imaging device, the measurement error due to the parallax value calculation error is the depth This is an error in the direction (Z-axis direction). Note that a measurement error in a three-dimensional direction that takes into account both a user-specified error and a parallax value calculation error may be calculated and used as reference information.

Note that the reference information calculation unit 71 may output only the measurement error, or may output it together with the first reference information and the second reference information of the third embodiment.

[Embodiment 5]
The measurement devices 1 and 7 of the first and second embodiments described above are configured to receive measurement point information, focus information, and distance information from outside the measurement device, and output measurement values and reference information to the outside of the measurement device. Thus, these are displayed on an external display device. However, the embodiment of the present invention is not limited to this, and for example, even the measurement apparatus having the configuration shown in FIG. 11 is included in the embodiment of the present invention. Hereinafter, the measurement apparatus 2 shown in FIG. 11 will be described as the fifth embodiment.

FIG. 11 is a block diagram illustrating a configuration of the measurement device 2 according to the fifth embodiment.

11 is different from the measuring apparatus 1 shown in FIG. 1 of the first embodiment in that the measuring apparatus 2 in FIG. 11 is not provided in the measuring apparatus 1 shown in FIG. And the input unit 15 is provided.

The imaging unit 13 corresponds to the imaging device described in the first embodiment. The imaging unit 13 includes an imaging device, generates a captured image, and outputs focus information such as information on a focal position and a depth of field at the time of imaging, and camera parameters. Furthermore, the imaging unit 13 generates and outputs distance information that is a distance value from the imaging unit 13 to the subject. The distance information may be calculated by a stereo method by obtaining two images by providing the image pickup unit 13 with two image pickup systems, or by providing a distance measuring device such as a TOF method in the image pickup unit 13. You may make it acquire. When a distance measuring device is provided, a processing unit different from the imaging unit 13 may be used. The acquired distance information corresponds to at least a part of the range captured in the image, and information on a position that can be designated as a measurement point is acquired.

The display unit 14 corresponds to the display device described in the first embodiment.

The input unit 15 corresponds to the input device described in the first embodiment. The input unit 15 displays the captured image on the display unit 14 and accepts designation of measurement points. The user designates the measurement point using the input unit 15 when designating the measurement point on the captured image. In the measurement apparatus 2 in FIG. 11, the display unit 14 and the input unit 15 have different configurations. However, as described in the first embodiment, a touch panel configured integrally with the display unit 14 and the input unit 15 is used. It may be provided instead of the unit 15.

As described above, the measurement device according to one embodiment of the present invention may include at least one of an input device, a display device, and an imaging device. As such a measuring device, for example, a device in which an application for executing the above-described steps is installed in a smartphone or a tablet-type portable information terminal is included.

[Example of software implementation]
The position information acquisition unit 10 and the reference information calculation units 11 and 71 of the measuring devices 1 and 7 may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or a CPU (Central Processing) Unit) and may be realized by software.

In the latter case, the measuring devices 1 and 7 include a CPU that executes instructions of a program that is software that realizes each function, and a ROM (Read Only Memory) in which the program and various data are recorded so as to be readable by a computer (or CPU). ) Or a storage device (these are referred to as “recording media”), a RAM (Random Access Memory) that expands the program, and the like. Then, the computer (or CPU) reads the program from the recording medium and executes it, thereby achieving the object of the embodiment of the present invention. As the recording medium, a “non-temporary tangible medium” such as a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. The program may be supplied to the computer via an arbitrary transmission medium (such as a communication network or a broadcast wave) that can transmit the program. The embodiment of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[Summary]
A measuring device (1, 7) according to aspect 1 of the present invention is a measuring device that measures a measurement value corresponding to a measurement point designated on a captured image, and includes reference information indicating the reliability of the measurement value. Computation units (reference information calculation units 11 and 71) are provided, and the calculation unit calculates the reference information such that the higher the degree of focusing of the measurement point in the captured image, the higher the reliability. To do.

According to the above configuration, the measurement device has a low degree of focusing of the measurement point in the captured image, low reliability of the measurement value according to the measurement point specified on the blurred image, and measurement in the captured image. The reliability of the measured value is calculated by calculating the reference information so that the reliability of the measured value corresponding to the specified measurement point on the non-blurred image is high. It is possible to suitably calculate reference information indicating

In the measurement device according to aspect 2 of the present invention, in the aspect 1, the measurement device acquires position information of the measurement point and focus information of the captured image, and calculates the calculation unit (reference information calculation unit 11, 71) may calculate the reference information based on the position information and the focus information.

According to the above configuration, since it is possible to determine the degree of focus of the measurement point in the captured image based on the position information and the focus information, it is preferable to calculate the reference information indicating the reliability of the measurement value. Can do.

In the measurement device according to aspect 3 of the present invention, in the aspect 2, the focus information is information representing a focus position corresponding to the captured image, and the reference information is a depth of field corresponding to the focus position. At least one piece of information may be included among information indicating whether or not the position of the measurement point is in the range and information indicating the distance between the position of the measurement point and the focus position.

According to the above configuration, it is possible to calculate reference information indicating whether the measurement point is inside or outside the depth of field, or how far the measurement point is from the focal position.

In the measurement device according to aspect 4 of the present invention, in the aspect 2, the focus information is information representing a depth of field corresponding to the captured image, and the reference information is in a range of the depth of field. The information may include at least one of information indicating whether or not the position of the measurement point is present and information indicating a distance between the position of the measurement point and the range of the depth of field.

According to the above configuration, it is possible to calculate the reference information indicating whether the measurement point is inside or outside the depth of field, or how far the measurement point is from the depth of field.

In the measurement device according to aspect 5 of the present invention, in the aspect 1, the calculation unit calculates a blur amount of the measurement point in the captured image based on luminance information of the captured image, and calculates the blur amount. The reference information may be calculated based on the above.

According to the above configuration, the blur amount is calculated based on the luminance information of the captured image, and the reference information is acquired based on the blur amount. Therefore, the reliability of the measurement value according to the blur amount is obtained regardless of the cause of the blur. The degree can be calculated.

The measurement apparatus according to Aspect 6 of the present invention is the measurement apparatus according to Aspect 5, wherein the reference information includes first reference information and second reference information, and the measurement apparatus includes position information of the measurement points, and The focus information of the captured image is acquired, and the calculation unit calculates a blur amount of the measurement point in the captured image based on luminance information of the captured image, and the first reference information based on the blur amount. And the second reference information may be calculated based on the position information and the focus information.

According to the above configuration, the user can accurately grasp the reliability of the measurement value based on the first reference information and the second reference information.

A measurement device according to aspect 7 of the present invention further includes a display unit that displays the measurement value in any of the above-described aspects 1 to 6, and the display unit displays the reference information in association with the measurement value. Alternatively, the display method of the measurement value may be varied depending on the reference information.

According to the above configuration, since the user can easily check the measurement value and the reference information, convenience is improved, which is preferable.

In the measurement device according to aspect 8 of the present invention, in the aspect 7, the display unit further displays the captured image, and displays a marker indicating the position of the measurement point superimposed on the captured image. The display method of the sign may be varied according to the reference information.

According to the above configuration, the user can easily confirm the measurement value and the reference information together with the captured image, which is preferable because convenience is improved.

The measurement device according to aspect 9 of the present invention may further include an input unit that displays the captured image and receives designation of the measurement point in the above aspects 1 to 8.

According to the above configuration, it is possible to suitably acquire the measurement point designated on the captured image.

The measurement device according to aspect 10 of the present invention may have a configuration further including an imaging unit having an imaging element that generates the captured image in the above aspects 1 to 9.

According to the above configuration, the captured image can be suitably acquired.

A measurement method according to an aspect 11 of the present invention is a measurement method for measuring a measurement value corresponding to a measurement point designated on a captured image, and includes a calculation step of calculating reference information indicating the reliability of the measurement value. In the calculation step, the reference information is calculated such that the higher the degree of focusing of the measurement point on the captured image, the higher the reliability.

According to the above configuration, the same effects as those of the above-described aspect 1 can be obtained.

The measurement device according to each aspect of the present invention may be realized by a computer. In this case, the measurement device is realized by the computer by operating the computer as each unit (software element) included in the measurement device. A measurement program of the measurement device and a computer-readable recording medium on which the measurement program is recorded also fall within the scope of the embodiment of the present invention.

The embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the embodiments of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

(Cross-reference of related applications)
This application claims the benefit of priority over the Japanese patent application filed on September 30, 2016: Japanese Patent Application No. 2016-194557, and by referring to it, all of its contents Included in this document.

DESCRIPTION OF SYMBOLS 1,7 Measuring apparatus 10 Position information acquisition part 11,71 Reference information calculation part (calculation part)
20, 90 Subjects 21, 22, 61, 62, 91 Measuring points 4 Imaging device (imaging unit)
5,6 Display device (display unit)
DESCRIPTION OF SYMBOLS 13 Imaging part 14 Display part 15 Input part 51,52 Display position 70 Blur amount calculation part

Claims (13)

A measurement device that measures a measurement value according to a measurement point specified on a captured image,
A calculation unit for calculating reference information indicating the reliability of the measurement value,
The measurement device, wherein the calculation unit calculates the reference information so that the reliability becomes higher as the degree of focusing of the measurement point in the captured image is higher. The measurement device acquires position information of the measurement point and focus information of the captured image,
The measurement apparatus according to claim 1, wherein the calculation unit calculates the reference information based on the position information and the focus information. The focus information is information representing a focus position corresponding to the captured image,
The reference information includes information indicating whether or not the position of the measurement point is within the range of depth of field corresponding to the focus position, and information indicating the distance between the position of the measurement point and the focus position. The measuring apparatus according to claim 2, wherein at least one piece of information is included. The focus information is information representing the depth of field corresponding to the captured image,
The reference information includes information indicating whether or not the position of the measurement point is within the range of the depth of field, and information indicating the distance between the position of the measurement point and the range of the depth of field. The measurement apparatus according to claim 2, comprising at least one piece of information. The calculation unit calculates a blur amount of the measurement point in the captured image based on luminance information of the captured image, and calculates the reference information based on the blur amount. The measuring device described in 1. The reference information includes first reference information and second reference information,
The measurement device acquires position information of the measurement point and focus information of the captured image,
The calculation unit is
Based on the brightness information of the captured image, calculate a blur amount of the measurement point in the captured image, calculate the first reference information based on the blur amount,
The measurement apparatus according to claim 1, wherein the second reference information is calculated based on the position information and the focus information. A display unit for displaying the measurement value;
7. The display unit according to claim 1, wherein the display unit displays the reference information in association with the measurement value, or changes a display method of the measurement value according to the reference information. The measuring device according to item 1. The display unit further displays the captured image, displays a sign indicating the position of the measurement point in a superimposed manner on the captured image, and changes the display method of the sign according to the reference information. 8. The measuring device according to claim 7, wherein The measuring apparatus according to claim 1, further comprising an input unit that displays the captured image and receives designation of the measurement point. The measuring apparatus according to claim 1, further comprising an imaging unit having an imaging element that generates the captured image. A measurement method for measuring a measurement value according to a measurement point designated on a captured image,
Including a calculation step of calculating reference information indicating the reliability of the measurement value,
In the calculation step, the reference information is calculated such that the higher the degree of focusing of the measurement point on the captured image, the higher the reliability. A measurement program for causing a computer to function as the measurement device according to any one of claims 1 to 10, wherein the measurement program causes the computer to function as the calculation unit. A computer-readable recording medium on which the measurement program according to claim 12 is recorded.

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