JPH0317506A - Inputting apparatus for three-dimensional image - Google Patents

Abstract

PURPOSE:To make it possible to obtain a correct three-dimensional image when the surface of an object has indentation and when a material has gloss by providing polarizing elements on optical paths between a laser light source and the object and between the object and a condenser lens respectively. CONSTITUTION:A laser light 5 from a laser light source 4 is transmitted through a polarizing element 8 by using mirrors 7a to 7c and led to a polygon mirror 6 rotating only a prescribed linearly polarized light, and the prescribed linearly polarized light of the laser light 5 is applied to an object 1 through an ftheta lens 9. A reflected light from the object 1 is reflected by a reflecting mirror 10 and then transmitted through a polarizing element 11 by using the lens 9 and the mirror 6, so that only the component of the prescribed linearly polarized light be taken out, and this component is condensed on a light-sensing element 13 through a condenser lens 12. From the light-sensing element 13, a position signal 14 showing a position whereat the said component is condensed is outputted, and it is subjected to computation in a height computation processing means 15 and then outputted as height data 16.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a three-dimensional image input device that reads height data of a two-dimensional area.

BACKGROUND OF THE INVENTION A three-dimensional measuring machine is a device that measures heights more precisely than conventional techniques. This three-dimensional measuring machine has an XY table and a contact for measuring two axes, and the object to be inspected is placed on an XY table and the contact is brought into contact with the object to read the displacement of the X, Y, and Z axes. ing. With such a three-dimensional measuring machine, it takes a lot of time and effort to obtain height data over a wide area, and the fineness of the XY pitch is limited by the size of the trench and contact. Occur. In addition to such a three-dimensional measuring machine, FIG. 5 shows a configuration applied to a mounted board inspection apparatus as a conventional example of a device for inputting three-dimensional images. In FIG. 5, 1 is an object, 2 is a conveying means for moving the object 1, 3 is an arrow indicating the moving direction of the conveying means 2,
4 is a laser light source, 5 is a laser beam from the laser light source 4,
6 is a polygon mirror 7 is a polygon mirror for laser beam 5
6 is a mirror for sending the light to the target, 9 is an fθ lens, 10 is a reflection mirror that collects the reflected light from the object, 12 is the condensing lens, 1
3 is a light receiving element for position detection, 14 is a position signal from the light receiving element 13, 15 is a height calculation processing means for converting the position signal 14 into a height signal, and 16 is height data output from this device. .

The operation of the above configuration will be explained below. The object 1 is moved in the direction of the arrow 3 by the conveying means 2, and guided to the polygon mirror 6 which is rotating using three mirrors 7 against the laser beam 5 from the laser light source 4. 6 and f
The laser beam 5 is irradiated perpendicularly onto the object l using the θ lens 9. This allows the entire surface of the object 1 to be scanned two-dimensionally.

1. By scanning the laser beam 5, the reflected light from the object 1 is reflected by the reflecting mirror 10, and the reflected light is further passed through the fθ lens 9, the polygon mirror 6, and the condensing lens 12 to detect the condensing position. The light is focused on the light receiving element 13 of. Light receiving element 1
3 outputs a position signal 14 indicating the focused position, and a height calculation processing means 15 performs calculation to convert the position signal into height data and outputs it as a height signal 16.

The principle of acquiring height information by the above-mentioned height calculation processing means 15 is as shown in FIG. In FIG. 6, 1 is an object, 4 is a laser light source, 17 is a condensing lens, 18 is a light receiving element, 14 is a position signal, polygon mirrors, mirrors, fθ lenses existing on the optical path of the conventional example, The reflection mirror is not shown, and the condenser lens 17 and the light receiving element 18 are arranged virtually. In this configuration, the height of the object l is A point 1
9. When point B is added, the diffusely reflected light 21 and the wave formed by irradiating these points with a laser beam are imaged separately at point C Z3 and point D on the light receiving element 18 via a condensing lens l7. In this way, the height displacement of the object 1 appears on the light receiving element 18 as a displacement of the condensing position, and the light receiving element 18 converts this displacement into an electrical signal to generate the position signal 14.

Problems to be Solved by the Invention However, in such a configuration, if the surface of the object 1 is made of an uneven and glossy material, the specular reflection light added to point B in FIG. Due to the influence of aberrations, etc., the image may be formed at point E on the light receiving element [8]. In general, in the case of glossy materials, the amount of specularly reflected light is often stronger than that of diffusely reflected light, so the position signal 14 of the light receiving element 18 is a correct position signal indicating point E 26. It becomes difficult to obtain. That is, in the conventional example, when the surface of the object is made of a glossy and uneven surface, it is difficult to obtain a correct three-dimensional image because of the disturbance caused by specularly reflected light. SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the conventional example, an object of the present invention is to provide a three-dimensional image input device that can obtain a correct three-dimensional image even when the surface of an object is made of an uneven and glossy material. It is.

Means for Solving the Problems The present invention provides a transport means for moving an object, a laser light source for emitting laser light, and a first polarizing element for transmitting only a specific linearly polarized component of the laser light. , a polygon mirror that scans the linearly polarized light in a one-dimensional direction, and f
A second lens that transmits only a predetermined linearly polarized light component from the reflected light from the object via the θ lens and the polygon mirror.
a polarizing element, a condensing lens that condenses the linearly polarized light of the reflected light, a light receiving element that outputs the condensed position as a position signal, and a height calculation processing means that calculates height data from the position signal. The one with the . Alternatively, a laser light source that emits linearly polarized light may be used instead of the first polarizing element.

According to the above-mentioned structure, the present invention includes a first polarizing element on the optical path between the laser light source and the object, and a first object and the focusing lens, in order to remove specularly reflected light before it reaches the focusing lens. The configuration is such that a second polarizing element is added on the optical path between the lenses.

Embodiment It has long been known in the field of optics that light reflected from an object has a specular reflection component and a diffuse reflection component. Furthermore, it is known that when an object is irradiated with linearly polarized light, the specular reflection component is linearly polarized, while the diffuse reflection component is unpolarized (1956 Japan Society of Applied Physics paper, "Measurement of the Reflection Characteristics of Paper Using Polarized Light I. (See “■”). Focusing on this optical reflection characteristic, the present invention irradiates linearly polarized light onto an object, and uses a polarizing element that transmits only the linearly polarized component orthogonal to the irradiated linearly polarized light from the reflected light. By selectively extracting only the three-dimensional images, it is possible to obtain accurate three-dimensional images. The principle of height data acquisition according to the present invention will be explained in detail using FIG.

In Figure 2, 1 is an object, 4 is a laser light source, 5 is a laser beam, 5 is a linearly polarized laser beam perpendicular to the main plane, and 8 is a first polarized light that transmits only linearly polarized light perpendicular to the main plane. 11 is a second polarizing element that transmits only linearly polarized light parallel to the plane of the book; 14 is a position signal; 17 is a condenser lens; 18 is a light receiving element; 19 is a point A at one height of the object 1; , 20
Point B121 at one height of object 1 is the diffusely reflected light from point A, SE is the diffusely reflected light from point B, and o is the diffusely reflected light 21 from point A.
The image forming point C,24 is the image forming point D,2 at the foot of the diffusely reflected light of point B.
5 is the specularly reflected light from point B, or a symbol indicating that this light contains a linearly polarized component perpendicular to the page and a linearly polarized component parallel to the page, ah, this light is perpendicular to the page. The symbol 4 indicates that this light contains only a linearly polarized component parallel to the plane of the paper.

In this configuration, the laser light 5 from the laser light source 4 becomes linearly polarized light perpendicular to the first polarizing element 8 to form laser light 5 and irradiate the object 1 with it.

Point A of object 1 19, B,! The diffusely reflected light 21 and η at 20 include a linearly polarized component perpendicular to the page surface and a linearly polarized component parallel to the page surface, but the second polarizing element 1l converts the linearly polarized light component perpendicular to the page surface or The removed light is imaged at point C 23 and point D 24 on the light-receiving element 18 as diffusely reflected light of linearly polarized light components parallel to the magazine plane. Since the specularly reflected light beam at point B is only a linearly polarized light component perpendicular to the paper surface, the second polarizing element 1
1 and does not reach the light receiving element 18. Similarly, since the regular reflection component (not shown) at point A is only a linearly polarized component perpendicular to the plane of the paper, it is removed by the second polarizing element 11 and does not reach the light receiving element l8. In this way, an image of only the diffusely reflected light from the object 1 is formed on the light receiving element 18, and the height displacement of the object 1 is focused on the light receiving element 1 without being disturbed by the specularly reflected light. This appears as a more accurate displacement of the light position, and the light receiving element 18 can convert this displacement into an electrical signal to obtain a more accurate position signal 14.

A first embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram showing a first embodiment of the three-dimensional image input device of the present invention. In FIG. 1, l is the object, 2 is a conveying means for moving the object 1, 3 is an arrow indicating the moving direction of the conveying means 2, 4 is a laser light source, 5 is a laser beam from the laser light source 4, and 6 is a Polygon mirror 7 is a mirror for sending the laser beam 5 to the polygon mirror 6, 8 is a first polarizing element that transmits only a predetermined polarized component from the laser beam 5, 9 is an fθ lens, and IO is a reflection of an object. 1l is a second polarizing element that transmits only a predetermined polarized light component from the reflected light; 12 is a condensing lens; 13 is a light receiving element for position detection; 14 is the position from the light receiving element 13. signal,
15 is a height calculation processing means for converting a position signal into a height signal, and 16 is a height signal output from this device.

The operation of this embodiment will be explained below. While the object 1 is moved in the direction of the arrow 3 by the conveyance means 2, the laser beam 5 from the laser light source 4 is transmitted through the first polarizing element 8 using three mirrors 7, and only a predetermined linearly polarized beam is rotated. A predetermined linearly polarized light of the laser beam 5 is irradiated perpendicularly onto the object 1 by the polygon mirror 6 and the fθ lens 9. This allows the entire surface of the object l to be scanned two-dimensionally with linearly polarized light. Further, by scanning the predetermined linearly polarized light of the laser beam 5, the reflected light from the object 1 is reflected by the reflecting mirror 10, and the reflected light is further reflected by the fθ lens 9.
The polygon mirror 6 is used to transmit the second polarizing element 11, and the linearly polarized light perpendicular to the first linearly polarized light is taken out and sent through the condensing lens 12 onto the light receiving element 13 for detecting the condensed position. Focus light. The light-receiving element 13 outputs a position signal 14 indicating the focused position, and the height calculation processing means 15 performs calculation to convert the position signal 14 into height data, which is output as height data 16. By repeating the above operations while rotating the polygon mirror 6 at a predetermined speed and moving the conveyance means 2 at a predetermined speed, a three-dimensional image can be obtained for the entire area of the object 1. I can do it.

In the above explanation of the operation, the principle of obtaining highly accurate height data has been described using FIG. 2, so detailed explanation will be omitted.

Next, the operations of the light receiving element 13 and the height calculation processing means 15 will be explained in detail using FIG. 3. FIG. 3 is a detailed pronk connection diagram of the light receiving element 13 and the height calculation processing means 15. In FIG. 3, 13 is a light receiving element, 14 is a position signal, 15 is a height calculation processing means, 15a is an I-■ converter, 1
5b is an A/D converter, 15c is a position calculation circuit, 15d is a height conversion circuit, and 16 is output height data. The operation will be explained below. Light receiving element 13 in this embodiment
used an element that provided a resistance layer on the surface of the light-receiving part as a light-receiving position detection element, and the value of the current flowing through both electrodes of the element was inversely proportional to the distance between the light-receiving position and each electrode. Therefore, the position signal 14
is the current value flowing through both electrodes. The height calculation processing means 15 converts the position signal 14 from the previous stage into the I-V converter 1.
5a performs current-to-voltage conversion, and further converts into a digital signal in A/D converter 15b to obtain quantized voltage values V, , V, , of both electrodes. Next, the position calculation circuit 15clC calculates the received light position data P according to the following formula (where K is an arbitrary constant), and the height conversion circuit 15d calculates the height acquisition principle as explained using FIG. Based on this, the light receiving position data P is converted into a value corresponding to height data, and height data 16 is obtained.
Obtain and output.

As described above, in this embodiment, the target object 1 is irradiated with linearly polarized light, and only the linearly polarized light perpendicular to the irradiated linearly polarized light is extracted from the reflected light and focused on the light receiving element 13, thereby disturbing the specularly reflected light. Acquire height data with a higher level of precision without being overly affected. In this embodiment, the beam spot diameter of the laser beam is set to 50 microns to obtain a three-dimensional image of one pixel in microns.

Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a block diagram showing a second embodiment of the three-dimensional image input device of the present invention. In FIG. 4, 1 is an object, 2 is a conveyance means for moving the object 1, 3 is an arrow indicating the moving direction of the conveyance means 2, 40 is a laser light source that emits linearly polarized light, and 5 is a light beam from the laser light source 40. A laser beam, 6 is a polygon mirror, 9 is an fθ lens, 1O is a reflection mirror that collects the reflected light from the object, 11 is a polarizing element that transmits only a predetermined polarized component from the reflected light, 12 is a condensing lens, 13 14 is a light receiving element for position detection, 14 is a position signal from the light receiving element, 15 is a height calculation processing means for converting the position signal into a height signal, and 16 is a height signal output from the apparatus.

The feature of the second embodiment of the present invention is that by employing a laser light source 40 that emits linearly polarized light as a light source, the mirror 7 and the first polarizing element 8 of FIG.
The configuration has been omitted, and the operation after the polygon mirror 6 is irradiated with linearly polarized light is the same as in the first embodiment. In order to eliminate the disturbance in the direction of linearly polarized light caused by the mirror and to obtain linearly polarized light with a more uniform polarization direction, the mirror 7 of the first embodiment was removed in this embodiment.

Effects of the Invention As described above, the present invention provides a transport means for moving an object, a laser light source for emitting a laser beam, and a first laser beam that transmits only a specific linearly polarized component of the laser beam.
a polarizing element, a polygon mirror that scans the linearly polarized light in a one-dimensional direction, and a second polarizing element that transmits only a predetermined component of the linearly polarized light from the reflected light from the object that has passed through the fθ lens and the polygon mirror. , by providing a condensing lens that condenses the linearly polarized light of the reflected light, a light receiving element that outputs the condensed position as a position signal, and a height calculation processing means that calculates height data according to the position signal, Alternatively, by adopting a laser light source that irradiates linearly polarized light instead of the first polarizing element, it is possible to obtain a highly accurate three-dimensional image, and it can be used as a device to replace the conventional three-dimensional measuring machine. This device is effective as a three-dimensional image input device for measuring the three-dimensional shape of objects.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a three-dimensional image input device according to a first embodiment of the present invention, and FIG.
Conceptual diagram of the height data acquisition principle common to the embodiments, Part 3
The figure is a block wiring diagram of the light receiving element and the height calculation processing means common to the first and second embodiments of the present invention, and FIG. 4 is the block wiring diagram of the three-dimensional image input device in the second embodiment of the present invention. 5 is a block diagram of a conventional three-dimensional drawing machine, and FIG. 6 is a conceptual diagram of the principle of acquiring height data in the configuration shown in FIG. DESCRIPTION OF SYMBOLS 1...Target, 2...Transportation means, 4...Laser light source, 6...Polygon mirror 8...l-th polarizing element, 9...fθ lens, lO...reflection Miller, 11.
...Second polarizing element, 12...Condensing lens, 13...
- Light receiving element, 15... height calculation processing means.

Claims (2)

[Claims] (1) A transport means for moving an object, a laser light source for emitting a laser beam, a first polarizing element for transmitting only a specific linearly polarized component of the laser beam, and a first polarizing element for transmitting the linearly polarized light in one dimension. A polygon mirror that scans in the direction and f^
A second lens that transmits only a predetermined linearly polarized light component from the reflected light from the object via the θ lens and the polygon mirror.
a polarizing element, a condensing lens that condenses the linearly polarized light of the reflected light, a light receiving element that outputs the condensed position as a position signal, and a height calculation processing means that calculates height data from the position signal. A three-dimensional image input device comprising: (2) The three-dimensional image input device according to claim 1, characterized in that a laser light source that emits linearly polarized light is used instead of the first polarizing element according to claim 1.