JPH09229632A - Image formation output apparatus and method, and shape measuring apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out measurement at high speed using a simple optical system by relatively moving a measuring part and an object to be measured and measuring the image information in an intermittent visual field illuminated by a linear slit light source. SOLUTION: A movable table 2 in which an object 1 to be measured is fixed is moved in a prescribed direction by a screw 3 driven by a motor 4. The motor 4 is provided with an encoder 5 which can detect and control the position of the table 2 moved by the screw 3. A time delay integration type TDI camera 8 is so installed above the object 1 to be measured as to make the optical axis 14 vertical to the object 1 to be measured. A laser is used as the linear slit light source 10 and light beam is slit in a narrow width by an optical system and radiated to the center part of the visual field of the camera 8. A laser controller 15 controls on and off of the laser light and the pulse lighting time of the laser is made to be equal to the line shift time of the camera 8 and the interval of the lighting is determined based on the interval of a necessary optical cutting plane line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for obtaining image information of an object to be measured by using a light cutting method, and
The present invention relates to a method and apparatus for non-contact measurement of a three-dimensional shape of an object to be measured.

[0002]

2. Description of the Related Art An object to be measured is irradiated with linear slit light,
A method of measuring the three-dimensional shape of an object to be measured, especially its height, by capturing the slit light projected onto the object under measurement from an angle different from that of the slit light is called the light-section method and is widely used. . Regarding slit light, a method of increasing the measurement speed by simultaneously projecting a plurality of slit lights in the camera field of view, or as disclosed in Japanese Patent Laid-Open No. 7-260443, a plurality of slit lights can be viewed in the camera field of view. A method is known in which the number of apparent slit lights is further increased by scanning inside and synthesizing a plurality of camera images.

[0003]

However, in the conventional optical cutting method as described above, since the three-dimensional shape of the object to be measured is captured by the surface, it is impossible to achieve a measuring speed higher than the frame rate of the camera. It is impossible. Further, when measuring a large area that does not fit within the field of view of the camera, it is necessary to repeat the movement, stop, and measurement, which causes a problem that the total measurement time becomes long. Further, there is a problem that an optical system for projecting a plurality of slit lights and moving them becomes complicated.

Therefore, an object of the present invention is to realize faster measurement by using a simpler optical system.

[0005]

In order to solve the above problems, an image information output apparatus according to the present invention comprises a measuring section including an image input apparatus and a linear slit light source, and the measuring section and the object to be measured. An image information output device including a relative moving means, wherein the measuring unit measures image information of an intermittent visual field illuminated by the linear slit light source.

The image information output device according to the present invention is
It is characterized in that it is provided with a measuring section comprising a progressive output camera having an information progressive output type image sensor and a linear slit light source, and a relative moving means for moving the measuring section and the object to be measured.

The linear slit light source is preferably capable of blinking.

Further, the image information output device according to the present invention is
A measuring unit including a two-dimensional image input device and a linear slit light source, a relative moving unit between the measuring unit and the object to be measured, and a plurality of images captured by the two-dimensional image input device in association with the relative movement are combined. It is characterized by having means.

The image information output method according to the present invention is
A method characterized by inputting image information of an intermittent visual field including a site of a measurement object to be irradiated with linear slit light, and extracting the image information while relatively moving the measurement object and the visual field. Consists of.

The image information output method according to the present invention is
The visual field including the part of the measured object irradiated with the linear slit light is imaged by the progressive output camera having the information progressive output type image sensor, and the progressive object is moved while relatively moving the measured object and the visual field. The method is characterized in that the information of the visual field is taken out from the output camera.

The linear slit light is preferably blinked.

The image information output method according to the present invention is
A field of view including a portion of the object to be measured illuminated by the linear slit light is imaged by a two-dimensional CCD camera, and while the object to be measured and the field of view are relatively moved, the two-dimensional CCD camera intermittently changes the field of view. The method is characterized in that images are taken out and the images are combined while being shifted by a distance corresponding to the taking-out interval.

Further, the shape measuring apparatus according to the present invention uses the above image information output apparatus to measure the shape of an object to be measured, for example,
It is intended to measure a three-dimensional shape including height information, in the above device, the shape information of the object to be measured from the measuring unit is extracted,
An image information processing unit for processing is added.

Furthermore, the shape measuring method according to the present invention measures the shape of the object to be measured, for example, a three-dimensional shape including height information, based on the information of the visual field extracted by the above-mentioned image information output method. It is a thing.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the first aspect of the present invention,
The object to be measured is irradiated with the linear slit light, which is imaged by a progressive output camera having an information progressive output type image sensor. While the object to be measured is relatively moved, imaging is repeated a necessary number of times.

To relatively move the object to be measured and the measuring section,
There are a configuration in which the object to be measured is fixed and the measuring unit is moved, and a configuration in which the object to be measured is moved and the measuring unit is fixed. Taking the latter as an example, FIG. 1 shows a configuration example of the present invention.

In the figure, reference numeral 1 denotes an object to be measured, which is fixed or fixed on the moving table 2 by an appropriate method. Table 2 is screw 3
The screw 3 is rotationally driven by, for example, a motor 4 as a drive source. The motor 4 is provided with an encoder 5 that can detect and control the rotation angle of the motor 4 and the position of the table 2 (object to be measured 1) moved by the screw 3. The table controller 6 controls the position and moving speed of the table 2 which is moved by the motor 4 via the screw 3 and the drive interval. In the present embodiment, the above-mentioned elements constitute the relative moving means 7 for moving the measuring section and the object to be measured.

Although the moving table 2 is used as described above in this embodiment, other means for moving the object to be measured,
For example, a belt conveyor or the like may be used. Further, the means for measuring the moving position is not limited to the encoder, and a linear sensor such as a magnetic scale can be used.
From the means for measuring the position, it is necessary to have a function of generating a signal in synchronization with the movement.

Above the DUT 1, a TDI camera 8 is provided.
And a linear slit light source 1 that irradiates the linear slit light 9 toward the DUT 1 from a position different from the TDI camera 8.
0 is provided. This TDI camera 8 constitutes a progressive output camera having an information progressive output type image sensor in the present invention.

The TDI camera is composed of an image pickup optical system and a TDI sensor. The imaging optical system forms an image on the TDI sensor, and the TDI sensor converts the image into electric charge,
The video circuit outputs it as an electric signal to the outside. Where T
The DI sensor is a Time Delay and Integration Image sensor, which means a time delay accumulation type sensor.

The operation principle and characteristics of the TDI camera will be described with reference to FIGS. In FIG. 2, the TDI camera 8
Focusing on the black spot 13 on the measurement target 12 that has entered the camera visual field 11, the state in which the black spot image enters the first line of the TDI sensor corresponds to the diagram of Step 1 in FIG. When the time further passes, the black dot image moves to the second line of the TDI sensor due to the movement of the measurement target. This state corresponds to the diagram of Step 2 in FIG. At the same timing as the movement of this image, the charges of the pixels on each line of the TDI sensor are sequentially moved to the corresponding pixels on the next line. That is,
Send it forward. This operation will be called line shift.
Line shift is repeated sequentially within the field of view of the TDI sensor,
When the end of the field of view (Step 5) is reached, the charge of the final line is output as a video signal. Therefore, when the TDI sensor is used, it is possible to continuously capture a moving image of the measuring object at high speed.

Further, a linear slit light source 10 for irradiating the linear slit light 9 is provided in the image pickup system of the above-mentioned TDI camera 8. In order to create a light section image of the DUT 1, the irradiation angle of the slit light 9 needs to be different from the optical axis 14 of the TDI camera 8. Further, when the longitudinal direction of the slit light 9 is aligned with the main scanning direction of the TDI camera 8 (see FIG. 3), the light section image can be efficiently captured.
The slit light 9 emits pulse light in synchronization with the movement of the object to be measured. That is, it blinks. By setting the pulse emission time of the slit light 9 within the one-line shift time of the TDI camera 8, it is possible to record a light-section image at the moment when the slit light 9 is turned on. Further, the slit light 9 is periodically pulsed in synchronism with the movement of the object to be measured, so that an image equivalent to the projection of a plurality of slit lights can be obtained.
It can be obtained by the DI camera 8.

The linear slit light 9 is not particularly limited, but a laser light is desirable in order to accurately produce a desired strong slit light. The emission of laser light is controlled by the laser controller 15.

FIG. 4 illustrates the slit light emission interval and the movement of the DUT 1. However, it should be noted that the light section image captured by the TDI camera 8 is only within the field of view of the TDI camera 8, so that if the light section image extends out of the field of view, the image of the protruding portion is lost.

The linear slit light 9 irradiated on the DUT 1
4 is a straight line on the reference surface (table surface) as shown in FIG. 4, but in the portion of the DUT 1, the curved shape is formed according to the three-dimensional shape (eg, height) of the DUT 1. . This deformed light shape is sequentially captured by the TDI camera 8.

The light section image obtained from the TDI camera 8 is
It is sent to the image information processing unit 16 (height information extraction unit) and converted into three-dimensional shape data of the DUT 1. The three-dimensional shape data, for example, height information can be extracted by an ordinary light cutting method.

FIG. 5 shows a height extraction method of a general light cutting method. The angle φ with respect to the line connecting the slit light projection system 17 and the TDI camera 8 is calculated based on the deviation amount Δx of the slit light measured by the TDI camera 8, and the distance Z is finally obtained by the principle of triangulation. be able to.

In FIG. 5, l is the distance between the TDI camera 8 and the image plane 18, L is the distance between the slit light projection system 17 and the TDI camera 8, and θ is the connection between the slit light projection system 17 and the TDI camera 8. The angle between the virtual line 19 and the irradiation slit light 20, Φ ₀ is the angle between the line 19 and the position of the slit light projected on the reference surface 21, and Φ ′ is the deviation angle between Φ ₀ and Φ. It represents.

In the above, Φ = Φ ₀ + Φ ′ Φ ′ = tan ⁻¹ (Δx / l), and the distance Z is obtained from the following equation. Z = [(tan θ · tan φ) / (tan θ + tan φ)] · L

In the present invention, the information progressive output type image sensor is, as the above-mentioned TDI sensor, a device which can output the information of the imaged visual field sequentially from one end portion of the visual field successively or intermittently. Anything is fine. Above TD
It may be one that integrates the amount of light like an I sensor, but need not be. Further, it is preferable to use a one having a two-dimensional field of view as shown in FIGS. On the other hand, regarding the configuration in which the object to be measured is fixed and the measuring unit is moved, only the relative moving method is different, and therefore the description thereof is omitted.

When moving the measurement unit and the object to be measured, the structure in which the measurement unit is moved and the object to be measured is fixed will be omitted. Next, in the second aspect of the present invention, an operation equivalent to that of the first aspect is performed by intermittently capturing the linear slit light with a two-dimensional CCD camera while always lighting. This will be described with reference to FIG.

The difference between FIGS. 1 and 6 described above is that the camera is the two-dimensional CCD camera 22, and the image output from the camera is connected to the image information processing unit 16 via the image synthesizing unit 23. is there. The two-dimensional CCD camera can capture an image of an object to be measured that relatively moves in the field of view by using a built-in electronic shutter or mechanical shutter. In the example of the configuration using the TDI camera in FIG. 4, the slit light is pulsed while continuously capturing images with the TDI camera. On the other hand, even if the object to be measured that relatively moves in the field of view illuminated by the slit light is intermittently imaged by a two-dimensional CCD camera and the images are shifted by a distance corresponding to the relative movement distance and combined, the result is equivalently shown in FIG. The effect shown in can be obtained.

[0033]

Next, a more specific method of implementing the image information output apparatus and method and the shape measuring apparatus and method of the present invention having the above-mentioned construction will be described. First, an example of the embodiment of the first aspect of the present invention will be described. As a means for moving the object to be measured, a table constituted by a ball screw or the like or a belt conveyor can be considered. Both require a power source (eg a motor) and means for measuring position (eg an encoder). From the means for measuring the position, a signal for synchronizing with the TDI camera 8 and the linear slit light 9 is generated. The table controller 6 controls the motor 4 based on the signal from the encoder 5 to cause the table 2 to perform a predetermined operation.

The TDI camera 8 is located above the DUT 1 and is arranged so that the optical axis 14 is perpendicular to the DUT 1. The timing signal for the line shift to the TDI camera 8 is supplied by processing the signal from the means for measuring the position (for example, an encoder).

On the other hand, a laser is used as the linear slit light source 10 to generate strong light. This light is slit-shaped into a narrow one using an optical system in which a cylindrical lens or the like is combined, and is arranged so as to irradiate the central portion of the visual field of the TDI camera 8. The irradiation angle of the linear slit light 9 is
The optical axis 14 of the TDI camera 8 is set to, for example, 45 degrees. The laser controller 15 functions as a power source of the laser light source and means for measuring the position (for example, an encoder).
It has a function to control ON / OFF of the laser light based on the signal from. The pulse lighting time of the laser is set to be the same as the line shift time of the TDI camera 8, and the laser pulse lighting interval is determined by the required interval of the optical cutting line. That is,
If the pulse lighting interval of the laser light is short, many light cutting lines are obtained, and if the pulse lighting interval is long, few light cutting lines are obtained.

Next, an example of an embodiment of the second aspect will be described. The means 7 for moving the object to be measured is the same as the above-mentioned example. The two-dimensional CCD camera 22 is provided with a camera equipped with an electronic shutter function and capable of transferring image information at high speed. For example, it is preferable to have a configuration in which a plurality of one-dimensional CCD sensors are integrated and the charges of each line can be simultaneously output. The two-dimensional CCD camera 22 is intermittently driven based on a signal from a means for measuring the position (for example, an encoder), and an instantaneous image is captured and transferred to the image synthesis unit 23. If the interval of image capturing is short, many light cutting lines are obtained, and if the interval is long, few light cutting lines are obtained. The linear slit light source 10 is the same as that of the above-mentioned embodiment, but in this case, it does not need to blink. The image synthesizing unit 23 receives a plurality of images obtained from the two-dimensional CCD camera 22 and, based on a signal from a means (for example, an encoder) for measuring the position, moves the image position by an amount corresponding to the relative movement amount. Shift and synthesize.

[0037]

As described above, even if a plurality of slit lights are simultaneously irradiated to the object to be measured, as long as the image is captured by using a normal CCD camera or the like, the image can be captured at a speed higher than the frame rate of the camera. I can't. In the present invention, the TDI camera can capture an image at a speed equal to or higher than the frame rate of a normal camera by synchronizing with the moving object to be measured. Moreover, in the case of measuring the three-dimensional shape of a large-area object to be measured, it is necessary to repeat the movement, stop, and measurement in the conventional method, and the total measurement time is long, but in the present invention, the main scanning of the TDI camera is performed. Since the image can be obtained by continuously feeding the table without stopping the table, the measurement time can be extremely shortened. Further, even with one slit light beam, the same effect as that obtained by projecting a plurality of slit light beams equivalently can be obtained, so that there is an advantage that the optical system for generating the slit light beam can be simplified. Even when the projection interval of the slit light on the object to be measured is changed, there is an advantage that only the interval of the blinking time of the slit light needs to be changed.

Therefore, according to the present invention, it is possible to measure the three-dimensional shape of the object to be measured at high speed and with high accuracy, even with a simple optical system.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a shape measuring apparatus according to an exemplary embodiment of a first aspect of the present invention.

FIG. 2 is a schematic configuration diagram showing a state of measurement by a TDI camera.

FIG. 3 is an explanatory diagram showing a moving state of an image measured by the method of FIG. 2 on a TDI sensor surface.

FIG. 4 is an explanatory diagram showing a state of measurement by the apparatus of FIG.

FIG. 5 is an explanatory diagram showing a measurement principle by a light section method.

FIG. 6 is a schematic configuration diagram of a shape measuring apparatus according to an exemplary embodiment of a second aspect of the present invention.

[Explanation of symbols]

 1 Object to be Measured 2 Moving Table 3 Screw 4 Motor 5 Encoder 6 Table Controller 7 Relative Moving Means 8 TDI Camera 9 Linear Slit Light 10 Linear Slit Light Source 11 TDI Camera Field of View 12 Measurement Target 13 Black Spot 14 Optical Axis 15 Laser Controller 16 Image Information processing unit 17 Slit light projection system 18 Image plane 19 Virtual line 20 Slit light 21 Reference plane 22 Two-dimensional CCD camera 23 Image combining unit

Claims (10)

[Claims] 1. An image information output device comprising: a measuring section comprising an image input device and a linear slit light source; and a relative moving means for moving the measuring section and the object to be measured. An image information output device for measuring image information of an intermittent visual field illuminated by a slit light source. 2. A measuring unit comprising a progressive output camera having an information progressive output type image sensor and a linear slit light source,
An image information output device comprising the measuring unit and means for moving the object to be measured relative to each other. 3. The image information output device according to claim 1, wherein the linear slit light source is capable of blinking. 4. A measuring section comprising a two-dimensional image input device and a linear slit light source, a relative moving means for moving the measuring section and an object to be measured, and a plurality of images picked up by the two-dimensional image input apparatus along with the relative movement. An image information output device comprising means for synthesizing the images of. 5. Inputting image information of an intermittent visual field including a portion of the measurement object to be irradiated with the linear slit light, and extracting the image information while relatively moving the measurement object and the visual field. An image information output method characterized by: 6. A field-of-view including a part of the object to be measured irradiated with the linear slit light is imaged by a progressive output camera having an information progressive-output image sensor, and the object to be measured and the visual field are relatively moved. An image information output method, characterized in that the information on the field of view is taken out from the progressive output camera while being kept at a minimum. 7. The image information output method according to claim 5, wherein the linear slit light is blinked. 8. A two-dimensional CCD camera captures an image of a field of view including a portion of the object to be measured illuminated by the linear slit light, and the object to be measured and the field of view are moved relative to each other and intermittently from the two-dimensional CCD camera. A method of outputting image information, wherein the image of the field of view is taken out, and the images are combined while being shifted by a distance corresponding to an extraction interval. 9. A shape measuring apparatus according to any one of claims 1 to 4, further comprising an image information processing section for extracting and processing object shape information from the measuring section. 10. A shape measuring method for measuring the shape of the object to be measured based on the information on the visual field taken out by the method according to claim 5.