Measuring device

Abstract

To provide a measuring device which can measure distance to a measurement-target accurately, even when the contrast of the measurement-targe surface is low.SOLUTION: A measuring device 1 comprises a plurality of light sources 3, 4, a detection unit 5, an arithmetic processing unit 13, and a base 2. The light sources 3, 4 emit a beam of light. The detection unit 5 detects light and outputs a detection signal. The arithmetic processing unit 13 processes the detection signal. The base 2 has a longitudinal direction. The plurality of light sources 3, 4 and the detection unit 5 are provided in the base 2 while being spaced apart from each other in a longitudinal base direction x. Each light source 3, 4 emits a beam of light 7, 8 to the measurement-targe 20. The detection unit 5 detects separately each reflected light 10 from the beams of light 7, 8 having been emitted by each light source 3, 4, and outputs a detection signal including information on an image-forming position of each reflected light 10 in the longitudinal base direction x. The arithmetic processing unit 13 calculates the distance from the base 2 to the measurement-targe 20 on the basis of the detection signal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a measurement apparatus that measures a measurement object using light. [Background technology]

[0002] Conventionally, autofocus cameras that automate focusing have been known. Autofocus cameras automatically measure the distance to a subject and adjust the focus. A typical example of a distance measurement method for autofocus cameras is the phase difference detection method (see, for example, Patent Document 1). The phase difference detection method detects an image of a subject using two one-dimensional imaging devices, and measures the distance to the subject from the phase difference (image shift) of the signals from the two devices. That is, optical information from the same subject is split into two optical paths using a split lens or the like, and each of the one-dimensional imaging devices installed in the two optical paths converts the information into an electrical signal, and the distance is measured from the phase difference between the two signals. In the phase difference detection method, if the subject is a landscape or a person, the phase difference (image shift) is clear and the distance can be measured, but in the case of a dark subject, low contrast (few shades), continuous patterns such as vertical stripes, or a subject moving at a high speed, erroneous distance information is output. For this reason, even if the phase difference detection method is applied to industrial measurement, the range of application is limited. In particular, if the subject is plate-like and has low contrast, it becomes difficult to measure the distance to the subject using the phase difference detection method.

[0003] Also, a distance measuring device that combines a light source with a linear image sensor (CCD element) or a PSD (position sensitive diode) is known for industrial measurement (see, for example, Patent Document 2). However, such a distance measuring device cannot detect the surface shape (for example, inclination or unevenness) of a target object unless the device or the target object moves.

[0004] Also, a TOF (Time of Flight) optical distance measuring device is known (see, for example, Patent Document 3). A TOF optical distance measuring device measures the time from transmitting light to receiving the light reflected by the object to be measured, and calculates the distance to the object. However, in the TOF type, since the transmitted light and the reflected light have a spread, it is difficult to accurately detect minute shapes (e.g., unevenness of the surface) of the object to be measured. In addition, the measurement of time in the TOF type requires high-speed signal processing, and the shorter the distance to the object to be measured, the greater the measurement error, and if the distance is large, the error due to the size of the object to be measured and the surrounding brightness increases. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2004-12815 A [Patent Document 2] Japanese Patent Publication No. 62-85813 [Patent Document 3] JP 2007-121116 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made to solve the above problem, and has an object to provide a measurement device that can measure the distance to an object with high accuracy even if the surface contrast of the object is low. [Means for solving the problem]

[0007] The measuring device of the present invention is a device for measuring a measurement object, and comprises a plurality of light sources that emit light rays, a detection unit that detects light and outputs a detection signal, a calculation processing unit that processes the detection signal, and a base having a longitudinal direction, wherein the plurality of light sources and the detection unit are provided on the base at a distance from each other in the longitudinal direction of the base, each of the light sources emits a light beam at the measurement object, the detection unit distinguishes and detects each reflected light of the light rays emitted by each of the light sources and outputs a detection signal including information on the imaging position of each reflected light in the longitudinal direction of the base, and the calculation processing unit calculates the distance from the base to the measurement object based on the detection signal.

[0008] In this measuring device, it is preferable that the light rays emitted by each of the multiple light sources are reflected at different irradiation positions on the object to be measured and detected by the detection unit, and the calculation processing unit measures the unevenness of the surface of the object to be measured by calculating the distance from the base to the multiple irradiation positions.

[0009] In this measurement device, it is preferable that the light rays emitted by each of the multiple light sources are reflected at different irradiation positions on the object to be measured and detected by the detection unit, and the calculation processing unit calculates the angle of the surface of the object to be measured relative to the base based on the calculation results of the distance from the base to the two irradiation positions.

[0010] In this measuring device, it is preferable that each of the plurality of light sources emits light rays having different wavelengths, and the detection section detects reflected light of the light rays emitted by each of the light sources by distinguishing between different wavelengths.

[0011] In this measuring apparatus, each of the light sources preferably includes a laser device that generates laser light and a focusing lens that focuses the laser light into a beam.

[0012] In this measuring device, the detection unit has an imaging device that detects the imaging position in the longitudinal direction of the base, and a focusing lens for focusing the reflected light on the imaging device, and it is preferable that the imaging device has a plurality of photosensitive arrays, and that the reflected light of light rays emitted by different light sources is detected by different photosensitive arrays.

[0013] This measuring device may further include a half mirror that splits the light incident on the detection unit into two optical paths, and the imaging device may have two photosensitive arrays arranged at a distance, and the reflected light of the light rays emitted by the different light sources may be split by the half mirror and detected by the different photosensitive arrays. Effect of the Invention

[0014] According to the measuring device of the present invention, if the object to be measured has a surface that diffusely reflects light, the distance to the object to be measured can be measured using reflected light, so that the distance to the object to be measured can be measured with high accuracy even if the contrast of the surface of the object to be measured is low. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a plan view showing the configuration of a measurement device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing the configuration of the device. [Diagram 3] 3(a), (b), and (c) are plan views showing the optical path when the distance to the measurement object is changed in the same device. [Figure 4] 4(a), (b), and (c) are diagrams showing output signals from the photosensitive array in the same device, corresponding to those in FIG. 3(a), (b), and (c). [Diagram 5] FIG. 5 is a diagram showing the image formation position of reflected light when the distance to the measurement object is changed in the same device. [Figure 6] FIG. 6 is a plan view illustrating an optical path in the measurement apparatus according to the second embodiment of the present invention. [Figure 7]7(a) and (b) are diagrams showing output signals from the photosensitive array in the device. [Figure 8] FIG. 8 is a plan view illustrating an optical path in the measurement apparatus according to the third embodiment of the present invention. [Figure 9] 9(a) and (b) are configuration diagrams of a detection unit in a measurement device according to a fourth embodiment of the present invention. [Figure 10] 10(a) and (b) are diagrams illustrating patterns of reflected light imaged on a photosensitive array in the measurement apparatus according to the first to fourth embodiments of the present invention, and Fig. 10(c) is a diagram illustrating a pattern of reflected light imaged on a photosensitive array in the measurement apparatus according to the fifth embodiment of the present invention. [Figure 11] Fig. 11(a) is a diagram showing a time-series operation of a detection unit in the measurement device according to the first to fifth embodiments of the present invention, and Fig. 11(b) is a diagram showing a time-series operation of a detection unit in the measurement device according to the sixth embodiment of the present invention. [Figure 12] FIG. 12 is a perspective view showing the configuration of a measurement device according to the seventh embodiment of the present invention. [Figure 13] FIG. 13 is a diagram showing the irradiation position of the light beam in the measurement device. [Figure 14] FIG. 14 is a block configuration diagram of a detection unit in the measurement devices according to the first to seventh embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (First embodiment) A measuring device according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5 and 14. As shown in FIGS. 1 and 2, the measuring device 1 is a device that measures a measuring object 20. When the measuring device 1 is used for an inspection, the measuring object 20 is an object to be inspected. When inspecting the surface shape of the measuring object, the measuring device 1 is also called a surface shape inspection device. The measuring object is, for example, a large structure such as a civil engineering structure, and the surface shape is, for example, the unevenness and angle of a concrete surface. The measuring device 1 is not limited to the use of inspecting the surface shape, and it is sufficient if it can at least measure the distance to the measuring object. The surface of the measuring object 20 is not a mirror surface, but diffusely reflects light (diffuse reflection). It is not necessary for the entire surface of the measuring object 20 to diffusely reflect light, and it is sufficient if the surface to be measured diffusely reflects light. Since the surface of the measuring object 20 diffusely reflects light, the angle of incidence and the angle of reflection of light do not have to be equal.

[0017] The measurement device 1 includes a plurality of light sources 3, 4, a detection unit 5, a calculation processing unit 13, and a base 2. The light sources 3, 4 emit light beams. The detection unit 5 detects the light and outputs a detection signal. The calculation processing unit 13 processes the detection signal. The base 2 is a member having a longitudinal direction. The plurality of light sources 3, 4 and the detection unit 5 are provided on the base 2 at a distance in the longitudinal direction x of the base. Each of the light sources 3, 4 emits light beams 7, 8 to a measurement object 20. The detection unit 5 distinguishes and detects each reflected light 10 of the light beams 7, 8 emitted by each of the light sources 3, 4, and outputs a detection signal including information on the imaging position (light receiving position) of each reflected light 10 in the longitudinal direction x of the base. The calculation processing unit 13 calculates the distance from the base 2 to the measurement object 20 based on the detection signal.

[0018] The measurement device 1 of this embodiment will be described in further detail. The measurement device 1 has a first light source 3 and a second light source 4 as multiple light sources 3 and 4. In an xyz Cartesian coordinate system, the base 2 has a longitudinal direction in the x-axis direction (base longitudinal direction x), and the light sources 3 and 4 emit light beams 7 and 8 within the xy plane. The distance from the base 2 to the measurement object 20 is the distance in the y-axis direction.

[0019] In this embodiment, the detection unit 5 is disposed between the first light source 3 and the second light source 4, and the distance between the first light source 3 and the detection unit 5 and the distance between the second light source 4 and the detection unit 5 are set to the same value B.

[0020] The detection unit 5 has a focusing lens 6, an imaging device 12, and a signal processing unit 50. The focusing lens 6 is focused so as to form an image on the imaging device 12 of a bright spot formed at an irradiation position 9 on the surface of the measurement object 20 by the light sources 3 and 4. Of the reflected light emitted from the light sources 3 and 4 and diffusely reflected on the surface of the measurement object 20, reflected light 10 in the direction of the optical axis 11 of the focusing lens 6 (the same as the direction of the optical axis 11 of the detection unit 5) is incident on the detection unit 5. The reflected light 10 incident on the detection unit 5 is imaged on the imaging device 12. The signal processing unit 50 processes the output signal of the imaging device 12, and outputs a detection signal to the calculation processing unit 13.

[0021] In the example shown in Figures 1 and 2, the radiation directions of the light sources 3 and 4 are set so that the irradiation positions 9 from the two light sources 3 and 4 coincide on the surface of the measurement object 20 located at a predetermined reference distance L from the base 2.

[0022] The distance in the y direction from the base 2 to the irradiation position 9 is L. If the angle between the base longitudinal direction x and the optical axis of the first light source 3 is θ (acute angle), the angle between the base longitudinal direction x and the optical axis of the second light source 4 is also θ due to the symmetry of the configuration. The calculation processing unit 13 calculates the distance from the base 2 to the measurement object 20 as L = B tan θ. The distance from the base 2 to the measurement object 20 is the distance from the irradiation position 9 to the surface of the imaging device 12 on the optical path. Note that, if the relative positions of the imaging device 12 and the focusing lens 6 with respect to the base 2 do not change during measurement, setting the base 2 as the starting point of the distance measurement is substantially equivalent to setting the imaging device 12 and the focusing lens 6 as the starting point of the distance measurement. This is because the distance dimension from the base 2 to the imaging device 12 and the focusing lens 6 is a constant value.

[0023] Here, the light beams emitted from the two light sources 3 and 4 intersect on a virtual plane at a reference distance L from the base 2. In FIG. 3(a), the distance of the measurement object 20 from the base 2 is the same as the reference distance L. The distance to the measurement object 20 does not have to be the same as the reference distance L. For example, as shown in FIG. 3(b), the two irradiation positions 9 may coincide on a virtual plane farther than the surface of the measurement object 20. In this case, the distance from the base 2 to the measurement object 20 is L-dL, which is dL closer than the reference distance L. Also, as shown in FIG. 3(c), the two irradiation positions 9 may coincide on a virtual plane closer to the base 2 than the surface of the measurement object 20. In this case, the distance from the base 2 to the measurement object 20 is L+dL, which is dL farther than the reference distance L. If the distance to the measurement object 20 is different from the reference distance L, the irradiation positions from the two light sources 3 and 4 will be different on the surface of the measurement object 20.

[0024] Figures 4(a), (b), and (c) correspond to Figures 3(a), (b), and (c), respectively. As shown in Figures 4(a), (b), and (c), the detection unit 5 detects the reflected light of the light beams 7 and 8 emitted by the light sources 3 and 4 at an image-forming position in the base longitudinal direction x according to the distance from the base 2 to the measurement target 20. The detection unit 5 outputs information on the image-forming position as a detection signal. This will be described in detail in Example 1.

[0025] The arithmetic processing unit 13 calculates the distance from the base 2 to the measurement object 20 based on the detection signal (see FIG. 1). Furthermore, the arithmetic processing unit 13 calculates the angle of the surface of the measurement object 20 with respect to the base 2 based on the calculation results of the distances from the base 2 to the two irradiation positions. Furthermore, the arithmetic processing unit 13 measures the unevenness of the surface of the measurement object 20 by calculating the distances from the base 2 to the multiple irradiation positions.

[0026] In this manner, the measurement device 1 can measure the angle and unevenness of the surface of the measurement object 20 without moving relatively to the measurement object 20.

[0027] The separation distance between the light sources 3 and 4 and the reference distance L are set appropriately depending on the field of application. The separation distance between the light sources 3 and 4 and the reference distance L do not need to be associated with each other, and are set individually. For example, the separation distance between the light sources 3 and 4 is 0.5 m, and the reference distance L is 3 m. The separation distance between the light sources 3 and 4 may be 1.5 m, and the reference distance L may be 10 m. Furthermore, without being limited to these numerical examples, the measurement device 1 may be scaled up or down.

[0028] Also, a first light source set consisting of light sources 3 and 4 and a second light source set at a position different from the first light source set may be provided on base 2, and the first light source set and the second light source set may be electrically switched depending on the distance between measurement object 20 and base 2, the required detection accuracy of the surface shape, etc. Furthermore, the number of such light source sets may be increased.

[0029] The measuring device 1 may be equipped with a vibration isolation mechanism to reduce the effects of mechanical vibrations from the surroundings.

[0030] The measuring device 1 may be used for vibration analysis of the measurement object 20. In general, when vibration analysis is performed, contact-type measurements are often performed in which an accelerometer or the like is placed on the surface of the measurement object 20. In contrast, when the measuring device 1 of the present embodiment is used for vibration analysis, it is a non-contact type in which measurements are performed at a distance from the measurement object 20. By using the measuring device 1, vibrations are analyzed as changes in the distance (y-axis direction) to the measurement object 20. Furthermore, if there are irregularities on the surface of the measurement object 20, even if the measurement object 20 vibrates in the base longitudinal direction x, it is possible to detect the vibrations. That is, it is possible to detect not only vibrations as changes in distance in a single axial direction (y-axis direction), but also vibrations in an axial direction (x-axis direction) perpendicular to that axis as changes in the surface shape. Since vibrations of a structure often include not only simple uniaxial vibrations but also complex multiaxial vibrations, vibration analysis using the measuring device 1 has many advantages.

[0031] When the measuring device 1 is used for vibration analysis, there are a first possible usage pattern in which the measuring device 1 is fixed (i.e., does not vibrate) and the measurement target 20 is vibrating, and a second possible usage pattern in which the measuring device 1 is integrated with a vibrating target (i.e., vibrates) and the measurement target 20 is fixed. The first usage pattern is considered to be the general pattern. In the second usage pattern, the measurement target 20 is, for example, a "fixed surface," and the measuring device 1 itself becomes a vibrating measurement target.

[0032] Each of the light sources 3 and 4 emits a light beam having a different wavelength from each other. The detection unit 5 detects the reflected light of the light beam emitted by each of the light sources 3 and 4 by distinguishing the difference in wavelength.

[0033] Each of the light sources 3 and 4 has a laser device that generates laser light and a condenser lens that condenses the laser light into a beam.

[0034] In this embodiment, the first light source 3 has a laser device that generates a red laser beam. The second light source 4 has a laser device that generates a green laser beam. When the detection unit 5 has a solid-state element such as a CCD as the imaging device 12, red and green are practically desirable because the wavelength sensitivity of the CCD is high in the photoelectric conversion sensitivity at red and green wavelengths, and there are few options for the characteristics, appearance, size, etc. of the blue laser device.

[0035] The light beams emitted by the light sources 3 and 4 are not limited to red and green, and may be visible light of different colors selected from the group consisting of red, green, and blue. In addition, the light beams emitted by the light sources 3 and 4 may be near-infrared light or infrared light as long as they can be distinguishably detected by the detection unit 5.

[0036] The light sources 3 and 4 may have light emitting diodes (LEDs) instead of laser devices. The configuration in which the light sources 3 and 4 have LEDs is particularly effective when the distance between the measurement device 1 and the measurement object 20 is short.

[0037] In this embodiment, the light sources 3 and 4 are supplied with power from a DC power source and emit light continuously. The detection unit 5 simultaneously detects the reflected light from each of the light sources 3 and 4 and distinguishes between them by wavelength division (difference in wavelength).

[0038] As a modification of this embodiment, the detection unit 5 may distinguish the reflected light from each of the light sources 3 and 4 by time division (difference in timing). That is, each of the multiple light sources 3 and 4 emits a light beam at a different timing, and the detection unit 5 distinguishes the reflected light of the light beams 7 and 8 emitted by each of the light sources 3 and 4 by the timing of detection. In this modification, the two light sources 3 and 4 emit light in a pulsed manner alternately. In a first period in which the first light source 3 emits light (emits a light beam) and the second light source 4 does not emit light, the detection unit 5 detects the reflected light from the first light source 3. In a second period in which the second light source 4 emits light and the first light source 3 does not emit light, the detection unit 5 detects the reflected light from the second light source 4. From the distances (multiple distances to the measurement object 20) calculated in the first period and the second period, the local inclination (angle) and unevenness of the measurement object 20 can be obtained. In this modified example, the inclination and the like can be obtained from the distance only after the first and second cycles are completed, so the measurement speed is halved. However, since the imaging device 12 of the detection unit 5 does not need to distinguish between different wavelengths, the options for the imaging device 12 are expanded, and the size and price of the measurement apparatus 1 can be reduced.

[0039] When using the measurement device 1 for vibration analysis, it is necessary to avoid time-division operation in which the multiple light sources 3 and 4 of the measurement device 1 emit light in a pulsed manner. In time-division operation, distance information from the light sources 3 and 4 is not detected at the same time, so the simultaneity of the distance information in the vibration analysis is lost, and preferable vibration analysis cannot be obtained.

[0040] The detection unit 5 will be described in more detail. The detection unit 5 has a focusing lens 6 and an imaging device 12 (see FIG. 2). The focusing lens 6 is a lens that focuses reflected light onto the imaging device 12. The focusing lens 6 forms an image of a bright spot on the surface of the measurement object 20 by the light sources 3 and 4 on the imaging device 12. The imaging device 12 detects the imaging position in the base longitudinal direction x (light receiving position in the base longitudinal direction x). The imaging device 12 has multiple photosensitive arrays 12a and 12b. Reflected light 10 of light rays emitted by different light sources 3 and 4 is detected by different photosensitive arrays 12a and 12b.

[0041] The imaging device 12 is housed within the housing of the detection unit 5. In this embodiment, the imaging device 12 is a one-dimensional imaging device and has two parallel rows of photosensitive arrays 12a and 12b. One photosensitive array 12a detects wavelength components from one light source 3, and the other photosensitive array 12b detects wavelength components from the other light source 4. The imaging device 12 is, for example, a CCD imaging device.

[0042] As a modification of the detection unit 5, the imaging device 12 may have one photosensitive array and a color filter. The color filter has two types of monochromatic filters that selectively transmit only the wavelength components of the light from the light sources 3 and 4. The two types of monochromatic filters cover the photosensitive array in a one-dimensional periodic pattern. The periodic pattern is, for example, a pattern of red, green, red, green.... The imaging device 12 distinguishes and detects the light transmitted through each of the two types of monochromatic filters.

[0043] As another modification of the detection unit 5, the imaging device 12 may be a two-dimensional imaging device. The detection unit 5 utilizes an output signal from a specific pixel (e.g., an area equivalent to a photosensitive array of two rows in which red and green photosensitive elements are arranged) among all pixels of the two-dimensional imaging device. Note that in a color two-dimensional imaging device used in a camera or the like, the pixels constituting a horizontal row are not configured as a "monochrome (red or green)" such as in a Bayer array or a complementary color array. For this reason, a complex method of configuring the desired pixel signal in the detection unit 5 is used.

[0044] As shown in FIG. 14, the detection unit 5 has a signal processing unit 50 in addition to the focusing lens 6 and the imaging device 12. The signal processing unit 50 has an electronic circuit, a CPU, a memory, and the like. The signal processing unit 50 has, as its functional parts, a signal readout unit 51, an amplifier circuit 52, an analog-digital conversion circuit 111, a storage unit 54, a slicer 55, a peak detection unit 56, and a position information acquisition unit 57. The signal processing unit 50 is accommodated in the housing of the detection unit 5. All or part of the functional parts of the signal processing unit 50 may be provided separately outside the housing. The signal readout unit 51 reads out a signal from the imaging device 12. The amplifier circuit 52 amplifies the signal read out by the signal readout unit 51. The amplifier circuit 52 has, for example, an automatic gain adjustment circuit. The analog-digital conversion circuit 111 converts the analog signal amplified by the amplifier circuit 52 into a digital signal. The storage unit 54 stores the digital signal in the memory 112. The slicer 55 extracts signals equal to or greater than a predetermined threshold from the digital signal. The peak detector 56 detects peak values ​​of the signals extracted by the slicer 55. The position information acquirer 57 acquires position information (imaging position in the base longitudinal direction x) of pixels at which peak values ​​appear in the imaging device 12, and outputs the information as a detection signal. In this embodiment, the detector 5 sequentially performs processing in the signal processor 50 in chronological order, in the order of the signal readout unit 51, the amplifier circuit 52, the analog-digital converter circuit 111, the storage unit 54, the slicer 55, the peak detector 56, and the position information acquirer 57.

[0045] The detection signal output by the detection unit 5 is input to the calculation processing unit 13. The calculation processing unit 13 has a CPU, a memory, etc., and functions by executing a program. The calculation processing unit 13 calculates the distance from the base 2 to the measurement object 20 based on the detection signal output by the detection unit 5. The calculation processing unit 13 also calculates the angle of the surface of the measurement object 20.

[0046] As described above, according to the measuring device 1 of this embodiment, if the measurement object 20 has a surface that diffusely reflects light, the distance to the measurement object 20 can be measured using reflected light, so that the distance to the measurement object 20 can be measured with high accuracy even if the surface contrast of the measurement object 20 is low.

[0047] The measuring device 1 may be used in combination with other inspection means. For example, the rough surface shape of the measurement object 20 is inspected using an autofocus mechanism having a focusing function for photography, and the detailed surface shape of a desired area is measured using the measuring device 1. The combination may be changed according to the required specifications. In addition to the autofocus mechanism, the rough surface shape inspection using other inspection means may use a range finder using infrared light developed for automatic driving of automobiles, a vehicle-mounted laser scanner device, or the like.

[0048] Second embodiment A measurement device according to a second embodiment of the present invention will be described with reference to Figs. 6 and 7. The measurement device 1 of this embodiment has a similar configuration to the first embodiment, but the arrangement of the light sources 3 and 4 is different. The same reference numerals are used to designate parts equivalent to those of the first embodiment. In the following description, the description of parts equivalent to those of the first embodiment will be omitted.

[0049] 6, in the measurement device 1 of this embodiment, the distances LRA, LGA between the multiple light sources 3, 4 and the detection unit 5 are set to different values. Note that the number of light sources is not limited to two, and may be three or more.

[0050] In this measurement device 1, light beams 7, 8 emitted from each of the multiple light sources 3, 4 are reflected at different irradiation positions 63, 64 on the measurement object 20 and detected by the detection unit 5. The calculation processing unit 13 calculates the distances from the base 2 to each of the multiple irradiation positions 63, 64, thereby measuring the unevenness (surface shape) of the surface of the measurement object 20.

[0051] Furthermore, the calculation processing unit 13 of this measurement device 1 calculates the angle WPS (surface tilt) of the surface of the measurement object 20 with respect to the base 2 based on the calculation results of each distance from the base 2 to the two irradiation positions 63, 64 (the distance to the irradiation position 63 and the distance to the irradiation position 64). Note that the median value of the distances to the irradiation positions 63, 64 is equal to L+dL.

[0052] In this manner, according to the measurement device 1 of this embodiment, the measurement device 1 calculates the distances to the multiple irradiation positions 63, 64 on the measurement object 20, and therefore can measure the unevenness and angles of the surface of the measurement object 20.

[0053] (Third embodiment) A measurement device according to a third embodiment of the present invention will be described with reference to Fig. 8. The measurement device 1 of this embodiment has a similar configuration to the first and second embodiments, but the arrangement of the light sources 3 and 4 is different. The same reference numerals are used to designate parts equivalent to the first and second embodiments. In the following description, the description of parts equivalent to the first and second embodiments will be omitted.

[0054] 8, in the measurement device 1 of this embodiment, the multiple light sources 3, 4 are disposed on one side of the detection unit 5 in the base longitudinal direction x, and the intervals LRA, LGA between the multiple light sources 3, 4 and the detection unit 5 are set to different values. Note that the number of light sources is not limited to two, and may be three or more.

[0055] In this measurement device 1, light beams 7 and 8 emitted from each of the multiple light sources 3 and 4 are reflected at different irradiation positions 63 and 64 on the measurement object 20 and detected by the detection unit 5. The calculation processing unit 13 calculates the distances from the base 2 to each of the multiple irradiation positions 63 and 64, thereby measuring the unevenness (surface shape) of the surface of the measurement object 20.

[0056] Furthermore, the calculation processing unit 13 of this measurement device 1 calculates the angle WPS (surface tilt) of the surface of the measurement object 20 with respect to the base 2 based on the calculation results of the distances from the base 2 to the two irradiation positions 63, 64.

[0057] According to the measurement device 1 of this embodiment, the measurement device 1 can calculate the distances to a plurality of irradiation positions 63, 64 on the measurement object 20, and can measure the unevenness and angles of the surface of the measurement object 20.

[0058] In the second and third embodiments described above, the optical axis of the detection unit 5 is oriented in the y-axis direction perpendicular to the base longitudinal direction x (see FIGS. 6 and 8). As a modification of the second and third embodiments, the optical axis of the detection unit 5 may be oriented in an oblique direction in the xy plane so as to face the intermediate position between the two irradiation positions 63 and 64.

[0059] The advantages of the measurement device 1 having a plurality of light sources 3 and 4 will be described. In the first embodiment, the measurement device 1 calculates the distance to the measurement object 20 based on the information of the imaging position (pixel position information) included in the output signal from the two photosensitive arrays 12a and 12b. In the second and third embodiments, the measurement device 1 calculates the distance to the measurement object 20 based on the information of the imaging position (pixel position information) from the plurality of photosensitive arrays 12a and 12b, thereby measuring the unevenness of the surface of the measurement object 20 and calculating the surface angle of the measurement object 20. The measurement device 1 of the first to third embodiments is compared with a distance measuring device having one light source and one photosensitive array. In an ideal environment, even a distance measuring device having one light source and one photosensitive array can obtain the distance to the measurement object based on the principle of triangulation. However, the distance measuring device cannot obtain the angle of the surface of the measurement object because the irradiation position of the light beam from the light source is one point. For this reason, in order to obtain the surface angle of a measurement object, such a distance measuring device must measure the distance to the measurement object while moving and calculate the surface angle of the measurement object based on the measurement result. In contrast, the measurement device 1 of the first to third embodiments can obtain the local shape (distance and angle) of the measurement object 20 without moving.

[0060] Furthermore, since the measurement device 1 has a plurality of light sources 3, 4 spaced apart from each other, it functions like a spatial diversity, improving availability. Even in a situation where reflected light from one light source 3 (or 4) is unlikely to reach the detection unit 5, the measurement device 1 can measure the distance to the measurement object 20 by using reflected light from the other light source 4 (or 3). Examples of such a situation include a situation where the reflectance at the irradiation position 63 (or 64) of the measurement object 20 is close to 100% (mirror surface) and the reflected light cannot reach the detection unit 5, or a situation where the irradiation position 63 (or 64) is in a recessed portion of the measurement object 20 and the irradiation position 63 (or 64) cannot be seen from the detection unit 5.

[0061] (Fourth embodiment) A measurement device according to a fourth embodiment of the present invention will be described with reference to FIG. 9. The measurement device 1 of this embodiment has a configuration similar to that of the first to third embodiments, and further includes a half mirror. The same reference numerals are used to designate parts equivalent to those of the first to third embodiments. In the following description, descriptions of parts equivalent to those of the first to third embodiments will be omitted.

[0062] 9(a) and 9(b), the measurement device 1 further includes a half mirror 91. The half mirror 91 splits the light incident on the detection unit 5 into two optical paths 96 and 97. The imaging device 12 includes two photosensitive arrays 92 and 93 that are spaced apart from each other. Reflected light of light beams emitted by different light sources 3 and 4 is split by the half mirror 91 and detected by the different photosensitive arrays 92 and 93.

[0063] In this embodiment, the half mirror 91 does not have wavelength selectivity. The detection unit 5 has two color filters having wavelength selectivity and two imaging devices. The imaging devices are one-dimensional imaging devices. Each imaging device has a photosensitive array 92, 93 that is sensitive to the wavelengths of the light sources 3, 4, respectively.

[0064] The half mirror 91 is disposed at an angle of 45° with respect to the optical axis of the focusing lens 90. Approximately 50% of the reflected light from the light sources 3 and 4 passes through the half mirror 91 (transmitted light 96), and the remaining approximately 50% is reflected in a direction at 90° (reflected light 97). Color filters that selectively transmit the reflected light from each of the light sources 3 and 4 are disposed on each of the optical paths 96 and 97 separated by the half mirror 91. Each of the color filters is disposed, for example, on the surface of the photosensitive arrays 92 and 93.

[0065] As a modification of this embodiment, the half mirror 91 may have wavelength selectivity. For example, the half mirror 91 has a multilayer film made of a dielectric material or the like having wavelength selectivity. A color filter having wavelength selectivity is not necessary. For example, the reflected light of the light beam emitted by the light source 3 passes through the half mirror 91 (transmitted light 96) and is detected by the photosensitive array 92. The reflected light of the light beam emitted by the light source 4 is reflected by the half mirror 91 (reflected light 97) and is detected by the photosensitive array 93.

[0066] According to the measurement device 1 of this embodiment, since the half mirror 91 is used, it is possible to select an imaging device that satisfies standards such as the number of pixels or pixel pitch of the photosensitive arrays 92 and 93 in accordance with the device specifications. On the other hand, although design factors such as the fixation of the half mirror 91 and the spatial position setting of the two photosensitive arrays 92 and 93 arise, the advantage of having a wider range of options for imaging devices is great.

[0067] Fifth embodiment A measurement device according to a fifth embodiment of the present invention will be described with reference to FIG. 10. The measurement device 1 of this embodiment has a configuration similar to that of the first to third embodiments, and further includes a cylindrical lens. The same reference numerals are used to designate parts equivalent to those of the first to third embodiments. In the following description, descriptions of parts equivalent to those of the first to third embodiments will be omitted.

[0068] The measurement device 1 of this embodiment has a cylindrical lens on the optical path from the light sources 3 and 4 to the photosensitive arrays 12a and 12b (see FIG. 2). The cylindrical lens is a lens having a shape obtained by cutting out a part of a cylinder. The cylindrical lens stretches the light beam emitted by the light sources 3 and 4 in one direction perpendicular to the emission direction.

[0069] At least one of the condenser lenses of the light sources 3 and 4 includes a cylindrical lens. As shown in Fig. 10(c), the cylindrical lens stretches the light beam emitted by the light sources 3 and 4 in one direction perpendicular to the emission direction.

[0070] In a modification of this embodiment, the focusing lens 6 of the detection unit 5 includes a cylindrical lens. As shown in Fig. 10(c), the cylindrical lens stretches the light beam incident on the imaging device 12 in one direction on the imaging device 12.

[0071] The spot size of the light beams emitted from the light sources 3 and 4 is small. Therefore, in the measurement device 1 without a cylindrical lens, as shown in Fig. 10(b), when the reflected light is focused on a light insensitive area (for example, a vertical register for reading out charge signals in an interline type two-dimensional sensor, or an intermediate area between the photosensitive arrays 12a and 12b in a one-dimensional sensor in which multiple photosensitive arrays are integrated) on the imaging device 12 (for example, a CCD) of the detection unit 5, the desired signal cannot be obtained (imaging pattern 101b).

[0072] 10(c), the measurement device 1 of this embodiment stretches the light beam incident on the imaging device 12 in one direction and deforms the spot of the light beam into an elliptical shape. As a result, the reflected light of the light beams emitted from the light sources 3 and 4 forms images on the photosensitive arrays 12a and 12b (imaging patterns 102a and 102b).

[0073] If the measurement device 1 does not include a cylindrical lens, the focal point of at least one of the focusing lens 6 of the detection unit 5 and the condenser lenses of the light sources 3 and 4 may be shifted to create an "out-of-focus" state, and the reflected light may be imaged on the photosensitive arrays 12a and 12b as shown in FIG. 10(a) (image patterns 100a and 100b). Such "blurring" reduces the light intensity at the center of the image patterns 100a and 100b and also increases the spread of the image patterns. This may make it difficult for the calculation processing unit 13 to perform the calculation process, but it is possible to use such "blurring" when the light intensity of the image patterns 100a and 100b is high.

[0074] Sixth embodiment A measurement device according to the sixth embodiment of the present invention will be described with reference to Fig. 11. The measurement device 1 of this embodiment has a similar configuration to the first to fifth embodiments, and is characterized by the processing in the detection unit 5. In the following description, descriptions of parts equivalent to those of the first to fifth embodiments will be omitted.

[0075] In this embodiment, the detection unit 5 performs parallel processing of a plurality of processes (see FIG. 11) among the processes (see FIG. 14) in the signal readout unit 51, the amplifier circuit 52, the analog-digital conversion circuit 111, the storage unit 54, the slicer 55, the peak detector 56, and the position information acquirer 57 of the signal processing unit 50. For example, after completing the processes in the signal readout unit 51, the amplifier circuit 52, the analog-digital conversion circuit 111, and the storage unit 54, the detection unit 5 performs the processes in the slicer 55, the peak detector 56, and the position information acquirer 57, and also performs the processes in the signal readout unit 51, the amplifier circuit 52, the analog-digital conversion circuit 111, and the storage unit 54 in the next cycle.

[0076] According to the measuring device 1 of this embodiment, it is possible to set long the time period required for the processing of each of the signal readout unit 51, the amplifier circuit 52, the analog-digital conversion circuit 111, and the storage unit 54, particularly the processing of each of the signal readout unit 51 and the analog-digital conversion circuit 111. This provides many advantages, such as a reduction in the driving frequency of the imaging device 12 such as a CCD, a reduction in driving power, an increase in light sensitivity due to an increase in the optical signal accumulation time, and further, the application of an analog-digital conversion circuit 111 with a slower conversion speed.

[0077] Seventh embodiment A measurement device according to a seventh embodiment of the present invention will be described with reference to Figs. 12 and 13. The measurement device 1 of this embodiment has a similar configuration to the first embodiment, and a base 2 is driven. The same reference numerals are used to designate parts equivalent to those of the first embodiment. In the following description, the description of parts equivalent to those of the first embodiment will be omitted.

[0078] 12, the measurement device 1 of this embodiment further includes a driving unit 120 that moves the base 2. The driving unit 120 moves the base 2 in the z-axis direction perpendicular to the xy plane formed by the base longitudinal direction x and the direction in which the light source emits light (y-axis direction), or around the axis of the base longitudinal direction x.

[0079] When the measurement object 20 is large, the range of movement in the z-axis direction becomes large, so it is preferable that the driving unit 120 moves the base 2 around the axis in the base longitudinal direction x.

[0080] As a modification of this embodiment, the driving unit 120 may drive the base 2 in the base longitudinal direction x in addition to the movement in the z-axis direction or around the axis in the base longitudinal direction x. This allows the measurement device 1 to measure the two-dimensional surface shape (zx plane) of the measurement object 20. The measurement device 1 measures the surface of the measurement object 20 by discretely sampling it. The spatial density of such sampling is determined by the driving unit 120 adjusting the speed of the base 2 in two directions (x-axis direction and z-axis direction). Also, the driving speed may be set so that the sampling density is large only in one direction (x-axis direction or z-axis direction).

[0081] The operation of the measuring device 1 according to the first to seventh embodiments of the present invention was specifically confirmed. This will be described in detail in examples. Examples 1 to 7 correspond one-to-one to the first to seventh embodiments, respectively. EXAMPLES

[0082] As Example 1, a measuring device 1 of the first embodiment was created (see Figs. 1 and 2). Two light sources 3 and 4 were arranged on a long base 2 symmetrically on both sides of a detection unit 5 with a distance B between them. The reference distance L was 3 m, the distance B between the light sources 3 and 4 and the detection unit 5 was 0.25 m, and the optical magnification of the focusing lens 6 was 1.74. Laser devices that generate red and green laser light were used as the light sources 3 and 4, respectively. A linear image sensor (manufactured by Toshiba Device & Storage Corporation, model number "TCD2564DG") was used as the imaging device 12 of the detection unit 5. This linear image sensor has three rows of 5400-pixel photosensitive arrays arranged in parallel with an inter-row distance of 28 μm (z direction), and each row has photosensitivity only to red, green, and blue, respectively. In this example, a photosensitive array 12a having photosensitivity only to red and a photosensitive array 12b having photosensitivity only to green were used. The size of the pixels constituting the photosensitive arrays 12a and 12b is 7×7 μm.

[0083] The detection unit 5 detects the reflected light (reflected laser light) with the photosensitive arrays 12a and 12b and outputs a detection signal. The detection signal includes the intensity of the reflected light on the imaging surface (surface of the photosensitive arrays 12a and 12b) and the imaging position (arrangement position of pixels) as information on the imaging position of the reflected light in the base longitudinal direction x.

[0084] One photosensitive array 12a detects reflected light from one light source 3, and the other photosensitive array 12b detects reflected light from the other light source 4. In other words, signals from different "subjects" are used. This embodiment is essentially different from the above-mentioned autofocus, which uses images from the same "subject."

[0085] As shown in Fig. 3(a), (b), and (c), when the distance to the measurement object 20 changes with respect to the reference distance L, the optical path from the light sources 3 and 4 to the imaging device 12 changes. Fig. 3(a), Fig. 3(b), and Fig. 3(c) respectively show the optical path when the distance to the measurement object 20 is the reference distance L, the distance to the measurement object 20 is shortened by dL, and the distance to the measurement object 20 is lengthened by dL. In Fig. 3(a), the laser beams from the light sources 3 and 4 are both irradiated to the position 9. In Fig. 3(b), the distance to the measurement object 20 is (L-dL), and compared to Fig. 3(a), the laser beam from the light source 3 is irradiated to the left of the position 9 (in the -x-axis direction). The laser beam from the light source 4 is irradiated to the right of the position 9 (in the +x-axis direction). The reflected light of each laser beam is imaged on the imaging device 12 via the focusing lens 6. The reflected light of the laser light from the light source 3 is detected by the photosensitive array 12a corresponding to red, and the reflected light of the laser light from the light source 4 is detected by the photosensitive array 12b corresponding to green. That is, in the case of FIG. 3(b), the pixel position on the photosensitive array 12a (which pixel from the left end of the sensor the reflected light hits) is different from the pixel position on the photosensitive array 12b, and the reflected light of the red laser is detected at a pixel position to the right of the reflected light of the green laser. Note that the two photosensitive arrays 12a and 12b are arranged 28 μm apart (column distance) in the z-axis direction, but in FIG. 3 they are depicted as being arranged at the same position in the z-axis direction. On the other hand, in FIG. 3(c), the distance to the measurement object 20 is (L+dL), and compared to FIG. 3(a), the laser light from the light source 3 is irradiated to the right of position 9 (in the +x-axis direction), and the laser light from the light source 4 is irradiated to the left of position 9 (in the -x-axis direction). The reflected light of each laser beam reaches the imaging device 12 via the focusing lens 6. The reflected light of the laser beam from the light source 3 is detected by a photosensitive array (linear sensor) 12a corresponding to red, and the reflected light of the laser beam from the light source 4 is detected by a photosensitive array 12b corresponding to green. That is, in the case of Fig. 3(c), the pixel position on the photosensitive array 12a (the pixel number from the left end of the sensor at which the reflected light hits) is different from the pixel position on the photosensitive array 12b, and the reflected light of the red laser is detected at a pixel position to the left of the reflected light of the green laser.

[0086] 4(a), (b), and (c) show the output from the photosensitive arrays 12a and 12b when the reference distance L changes. FIG. 4(a), FIG. 4(b), and FIG. 4(c) correspond to FIG. 3(a), (b), and (c), respectively. In FIG. 4, the notations "G" and "R" indicate the output signals from the photosensitive arrays 12a and 12b, respectively. The horizontal axis indicates the imaging position in the base longitudinal direction x on the photosensitive arrays 12a and 12b, and the vertical axis indicates the magnitude of the output signals from the photosensitive arrays 12a and 12b, with the upper row being the photosensitive array 12b and the lower row being the photosensitive array 12a. The change in the distance to the measurement target 20 can be obtained by obtaining the difference in pixel position information (information on the imaging position in the base longitudinal direction x) at which the peak value of the output signal appears. That is, the reference distance L is used as a reference value, and the displacement dL from the reference distance L is obtained as distance information.

[0087] In this way, the pixel position (imaging position) that detects red and the pixel position that detects green depend on the displacement dL, and it is possible to obtain the displacement dL from the difference dN in the number of pixels corresponding to the difference between the two pixel positions. FIG. 5 shows the relationship between the displacement dL and the difference dN in the number of pixels. The vertical axis (difference dN in the number of pixels) in FIG. 5 shows positive and negative values. When red is to the left of green, the difference dN in the number of pixels is positive, and when red is to the right of green, the difference dN in the number of pixels is negative. As shown in FIG. 5, when the displacement dL is 13 cm, the difference dN in the number of images is 5400, and the reflected light of the red laser is imaged at one end (for example, the pixel at the left end) of the photosensitive array 12a, and the reflected light of the green laser is imaged at the other end (for example, the pixel at the right end) of the photosensitive array 12b. When the difference dN in the number of images is 1, the displacement dL is 0.024 mm.

[0088] The measuring device 1 of Example 1 was able to detect the displacement amount dL within a maximum range of ±13 cm and a minimum range of ±0.024 mm. In other words, the measuring device 1 was able to measure the unevenness of the surface of the measurement object 20 within a range of ±0.024 mm to ±13 cm with respect to the reference distance L, and was able to obtain the surface shape of the measurement object 20.

[0089] The photosensitive array 12a is covered with a red filter, and the photosensitive array 12b is covered with a green filter. The red and green filters are often made of resin, and the red filter cannot completely block green or blue, and the green filter cannot completely block red or blue. As a result, color components other than the desired color components are detected, inducing so-called color mixing. The spectral sensitivity characteristics of the imaging device 12 (linear sensor, model number "TCD2564DG") are 94% (relative value) sensitivity to a red laser (wavelength of about 650 nm) and 86% sensitivity to a green laser (wavelength of about 532 nm). On the other hand, about 1% of red light with a wavelength of 650 nm passes through the green filter, and about 1% of green light with a wavelength of 532 nm passes through the red filter. In other words, the selection ratio of red and green light in each filter is about 100, and color mixing is about 1%. As a result, the color mixture components contained in the output signals from the photosensitive arrays 12a and 12b of the imaging device 12 were 1% or less, and had almost no effect on the measurement of the object 20 to be measured. EXAMPLES

[0090] As shown in FIG. 6, the measurement device 1 of the second embodiment has the same configuration as that of the first embodiment, but the arrangement of the light sources 3 and 4 is different. The virtual plane 60 is a virtual plane that is a reference distance L away from the base 2 in the y-axis direction. The light sources 3 and 4 are arranged so that the laser light (light beams 7 and 8) from the light sources 3 and 4 intersect on the virtual plane 60. The measurement target 20 is arranged at a distance dL from the virtual plane 60 and tilted at an angle WPS. The irradiation positions 63 and 64 are positions where the light beams 7 and 8 from the light sources 3 and 4 are irradiated, respectively. The reflected light reflected at the irradiation positions 63 and 64 is imaged on the surface of the imaging device 12. Note that the imaging device 12 has two rows of photosensitive arrays 12a and 12b integrated at intervals of 28 μm (z-axis direction), but the photosensitive arrays 12a and 12b are illustrated as if they were on the same plane.

[0091] Unlike Example 1, Example 2 is characterized in that the light sources 3 and 4 are arranged on both sides of the base 2 in the base longitudinal direction x, at distances LRA and LGA from the detection unit 5, respectively. That is, the light sources 3 and 4 are arranged asymmetrically with respect to the detection unit 5. The reference distance L is 3 m, the distance LRA is 0.2 m, and the distance LGA is 0.3 m. The optical magnification of the focusing lens 6 is 1.74, the same as in Example 1. The size of the pixels constituting the photosensitive arrays 12a and 12b is 7 × 7 μm, the same as in Example 1.

[0092] In Fig. 6, the reflected light from the irradiation position 63 is imaged on one photosensitive array 12a, and the reflected light from the irradiation position 64 is imaged on the other photosensitive array 12b. The respective imaging positions counted in number of pixels (the number of pixels counted from the center of the photosensitive array, which can be positive or negative) are designated as PIXR and PIXG (not shown). Fig. 7(a) shows the change in the imaging positions PIXR and PIXG of the imaging device 12 (vertical axis) with the displacement amount dL as a parameter (horizontal axis). Fig. 7(b) shows the change (number of pixels) in the imaging positions PIXR and PIXG of the imaging device 12 with the angle WPS as a parameter. Fig. 7(a) shows the change (number of pixels) in the imaging positions PIXR and PIXG when the angle WPS is 5° and the displacement amount dL changes from -10 cm to +10 cm. 7(b) shows the change (number of pixels) in the imaging positions PIXR and PIXG when dL is 10 cm and WPS changes from -10° to +10°. In this way, the displacement dL of the measurement object 20 from the reference distance L and the tilt angle WPS can be calculated based on the imaging positions PIXR and PIXG (imaging positions in the base longitudinal direction x) obtained from the imaging device 12.

[0093] In Fig. 7(a), the angle WPS is set to 5°, and in Fig. 7(b), the amount of displacement from the reference distance L is set to 10 cm, and the image positions PIXR and PIXG are determined. Meanwhile, when operating the measurement device 1, it is required to calculate the amount of displacement dL and the angle WPS from the image positions PIXR and PIXG obtained by actual measurement. The amount of displacement dL and the angle WPS are calculated from the image positions PIXR and PIXG by using the following formulas 1 and 2.

[0094]

number

[0095]

number

[0096] The angle WPS and the amount of displacement dL were calculated using Formula 1 and Formula 2. The values ​​in Table 1 below were used in the calculation.

[0097] [Table 1]

[0098] When the imaging position PIXR of the photosensitive array 12a is −1664 and the imaging position PIXG of the photosensitive array 12b is 2460, the angle WPS is 5.04°, the displacement dL is 0.1 m, and the distance from the base 2 to the measurement object 20 is L+dL=3.1 m.

[0099] In this way, the measurement device 1 of Example 2 was able to obtain the distance to the measurement object 20 and the angle WPS of the measurement object 20 even when the measurement object 20 and the measurement device 1 were fixed and unmoving. EXAMPLES

[0100] As shown in FIG. 8, the measurement device 1 of the third embodiment has the same configuration as that of the second embodiment, but the arrangement of the light sources 3 and 4 is different. The first light source 3 is arranged on one side (the right side in FIG. 8) of the detection unit 5 at a distance LRA. The second light source 4 is arranged on the same side at a distance LGA. The light sources 3 and 4 are arranged so that the laser beams 7 and 8 from the light sources 3 and 4 intersect on the surface of the virtual plane 60 located at the reference distance L. In this configuration, the irradiation positions 63 and 64 on the surface of the measurement object 20 are irradiated with the laser beams 7 and 8, respectively, and both are located on one side (the left side in FIG. 8) of the optical axis 11 of the focusing lens 6. The reflected light from the irradiation positions 63 and 64 is imaged on the imaging device 12 in a 1 / 2 area on one side of the optical axis 11 (the right side in FIG. 8). That is, the image is not formed on the other 1 / 2 area of ​​the imaging device 12 (the left side in FIG. 8). Therefore, by disposing the imaging device 12 closer to one side of the optical axis 11 (the right side in FIG. 8), there is an advantage that the effective area of ​​the imaging device 12 can be expanded.

[0101] The measurement device 1 of the third embodiment was able to obtain the distance to the measurement object 20 and the angle WPS of the measurement object 20, similarly to the second embodiment. EXAMPLES

[0102] In the first to third embodiments, the imaging device 12 is a one-dimensional imaging device, and a plurality of photosensitive arrays 12a, 12b are integrated on the same chip. There are few types of imaging devices 12 in which a plurality of photosensitive arrays 12a, 12b are integrated on the same chip, and the options that satisfy the desired specifications, such as the number of pixels, pixel arrangement pitch, and arrangement pitch of the photosensitive arrays, are limited.

[0103] Therefore, the measurement device 1 of Example 4 realizes the function of the imaging device 12 having a plurality of photosensitive arrays 12a, 12b in Examples 1 to 3 by a half mirror 91 and two one-dimensional imaging devices having a single photosensitive array, as shown in Figures 9(a) and (b). The measurement device 1 of Example 4 has a focusing lens 90 that focuses reflected light on the photosensitive region of the imaging device, a half mirror 91, and two photosensitive arrays 92, 93. The photosensitive arrays 92, 93 are one-dimensional imaging devices.

[0104] The half mirror 91 has a function of transmitting half of the incident light 95 (transmitted light 96) and reflecting the other half of the light (reflected light 97). The half mirror 91 is disposed at an angle of 45° to the incident light, and the reflected light 97 is directed downward by 90°.

[0105] The measuring device 1 of the fourth embodiment was able to obtain the distance to the measurement object 20 and the angle WPS of the measurement object 20, similarly to the first to third embodiments. EXAMPLES

[0106] When lasers are used as the light sources 3 and 4 of the measuring device 1 in the first to third embodiments, the spot size of the laser light changes depending on the focusing lens of the laser light output unit, the distance to the measurement object 20, and the like. When the spot size (diameter) of the laser light at the irradiation positions 63 and 64 of the measurement object 20 is 1 mm, the spot size when the reflected light reaches the photosensitive surface of the photosensitive arrays 12a and 12b is 1.74 mm (the optical magnification of the lens is 1.74). The spot size corresponds to 250 pixels. Since the two photosensitive arrays 12a and 12b (linear sensors) are arranged 28 μm apart (corresponding to 4 pixels), it is not necessary to focus on each of the two photosensitive arrays 12a and 12b. That is, the focusing lens 6 can focus the red and green reflected lights at the desired positions of the photosensitive arrays 12a and 12b.

[0107] The spot size of the laser light at the irradiation positions 63, 64 is not limited to 1 mm, and when the required specifications for the measurement device 1 are different, the spot size of the laser light at the irradiation positions 63, 64 may become extremely small (for example, several tens of μm). In such a case, the measurement device 1 of the first embodiment cannot image the light beam from the light source 3 or 4 reflected at the irradiation positions 63, 64 onto the two photosensitive arrays 12a and 12b. For example, when an image is formed on the photosensitive array 12a for red, the reflected green light is imaged outside the photosensitive array 12b for green.

[0108] 10(a), (b), and (c) show the imaging state of the reflected light on the two photosensitive arrays 12a and 12b. FIG. 10(a) shows the imaging state when the spot size of the laser light at the irradiation positions 63 and 64 is 1 mm (the spot size when it reaches the photosensitive surface of the photosensitive arrays 12a and 12b is 1.74 mm). In FIG. 10(a), the circular imaging patterns 100a and 100b are the reflected light patterns from the light sources 3 and 4, respectively, imaged on the surface side of the photosensitive arrays 12a and 12b. The imaging patterns 100a and 100b are shifted up and down, but there may be a case where there is no shift. In FIG. 10(a), the imaging patterns 100a and 100b are detected by the respective photosensitive arrays 12a and 12b, and information on the center position of the imaging patterns 100a and 100b, i.e., the imaging position in the base longitudinal direction x, is obtained from the pixel corresponding to the maximum level of the output signal. 10B shows the imaging state on the two photosensitive arrays 12a and 12b when the spot size becomes extremely small. The imaging pattern 101a is detected by the photosensitive array 12a, but the imaging pattern 101b is not detected.

[0109] To avoid such inconvenience, the measurement device 1 of the fifth embodiment includes a cylindrical lens in the condenser lens of the light sources 3 and 4. The cylindrical lens stretches the light beams emitted from the light sources 3 and 4 only in one direction (z-axis direction) to convert them into an elliptical shape. FIG. 10(c) shows the imaging state of the reflected light on the two photosensitive arrays 12a and 12b in the measurement device 1 of the fifth embodiment. The imaging pattern 102a and the imaging pattern 102b overlap the photosensitive areas of the photosensitive arrays 12a and 12b, respectively. That is, in the measurement device 1 of the fifth embodiment, the imaging patterns 102a and 102b due to the reflected light are detected from both the photosensitive arrays 12a and 12b. EXAMPLES

[0110] The operation of the detection unit 5 in the measurement device 1 was confirmed. The signal processing unit 50 of the detection unit 5 has a signal readout unit 51, an amplifier circuit 52, an analog-digital conversion circuit 111, a storage unit 54, a slicer 55, a peak detector 56, and a position information acquisition unit 57 (see FIG. 14). The slicer 55, the peak detector 56, and the position information acquisition unit 57 are referred to as a functional block 113. FIGS. 11(a) and (b) show the operation of the detection unit 5.

[0111] In a comparative example for Example 6, as shown in FIG. 11(a), the signal readout unit 51 of the detection unit 5 sequentially reads out pixel signals of the photosensitive array 110 (shown as 7 pixels) of the imaging device 12 as time-series signals. The analog-digital conversion circuit 111 converts the signals into digital signals. The storage unit 54 sequentially stores the digital signals in the memory 112. Thus, in Comparative Example 1, the detection unit 5 performs such operations in a time-series manner. Assuming that the signal readout from the photosensitive array 110 is 10 MHz (the analog-digital conversion circuit 111 operates at a period of 0.1 microseconds / pixel), the number of pixels is 2700, and the time required for storage in the memory 112 is extremely short, the time required from signal readout to storage is 0.27 milliseconds. The function block 113 performs many calculation processes, and the time required for the process is 0.73 milliseconds, although it depends on the configuration of the measurement device 1. In other words, the time from when the signal readout from the photosensitive array 110 is started to when the detection signal is output from the function block 113 is 1 millisecond.

[0112] In the sixth embodiment, as shown in FIG. 11(b), the time-series processing of the signal in the detection unit 5 is improved to a plurality of parallel processing. In the sixth embodiment, in cycle N, after the detection unit 5 finishes the processing of the signal readout unit 51, the amplifier circuit 52, the analog-digital conversion circuit 111, and the storage unit 54, the detection unit 5 performs the processing of the slice unit 55, the peak detection unit 56, and the position information acquisition unit 57 (the processing of the functional block 113), and performs the processing of the signal readout unit 51, the amplifier circuit 52, the analog-digital conversion circuit 111, and the storage unit 54 in the next cycle (N+1). This allows the time period required for the processing of the signal readout unit 51, the amplifier circuit 52, the analog-digital conversion circuit 111, and the storage unit 54, particularly the processing of the signal readout unit 51, the amplifier circuit 52, and the analog-digital conversion circuit 111, to be set long.

[0113] In the sixth embodiment, even if the period of one cycle (cycle N), i.e., the cycle period, is 1 millisecond and the processing in the functional block 113 is 0.73 milliseconds, it is sufficient to perform the process from reading from the photosensitive array 110 to storing in the memory 112 in 1 millisecond.

[0114] The detection unit 5 in Example 6 (see FIG. 11b) was compared with the detection unit 5 in the comparative example (see FIG. 11(a)). In Example 6 and the comparative example, the photosensitive array 110 was a CCD with 2700 pixels. The cycle period was the same time (1 millisecond).

[0115] The readout period from the pixels of the photosensitive array 110 was 0.1 microseconds (frequency was 10 MHz) in the comparative example, and 0.37 microseconds (frequency was 2.7 MHz) in Example 6. The conversion time in the analog-to-digital conversion circuit 111 was 0.1 microseconds in the comparative example, and 0.37 microseconds in Example 6.

[0116] In the sixth embodiment, the read clock frequency (the inverse of the read cycle) is roughly 1 / 4 of that in the comparative example, and a significant reduction in power consumption is achieved. Furthermore, in the sixth embodiment, the requirement for high speed performance of the conversion IC constituting the analog-digital conversion circuit 111 is significantly relaxed. Thus, the sixth embodiment has a great advantage in that it employs parallel processing. EXAMPLES

[0117] In Examples 1 to 5, the measurement device 1 and the measurement object 20 are stationary. When the measurement object 20 is moved along the base longitudinal direction x, the surface shape (e.g., unevenness) of the measurement object 20 in the base longitudinal direction x can be continuously measured. However, the surface shape along the vertical direction (z-axis) cannot be measured.

[0118] As shown in FIG. 12, the measurement device 1 of Example 7 adds a driving unit 120 to the measurement device 1 of Examples 1 to 3. The driving unit 120 rotates the base 2, the light sources 3 and 4, and the detection unit 5 around the x-axis. Due to this rotation, the irradiation position 9 on the surface of the measurement object 20 moves along the z-axis to the irradiation position 9a. The reflected light 10a from the irradiation position 9a is incident on the focusing lens 6. This allows the measurement device 1 of Example 7 to measure the shape of the measurement object 20 in the z-axis direction.

[0119] 13(a) and (b) show the trajectories of the irradiation positions 9, 9a of the laser light when the measurement object 20 moves in the base longitudinal direction x of the measurement device 1. As shown in FIG. 13(a), in the measurement device 1 of Example 1 that does not have the driving unit 120, the trajectory of the irradiation position 9 of the laser light is constant in the z-axis direction. As shown in FIG. 13(b), the measurement device 1 of Example 7 scans the irradiation position 9a of the laser light in the z direction. In this way, in Example 7, the movement of the measurement object 20 and the movement of the measurement device 1 by the driving unit 120 are combined to measure the two-dimensional surface shape of the measurement object 20.

[0120] The present invention is not limited to the configuration of the above embodiment, and various modifications are possible within the scope of the present invention. For example, the base 2 is not limited to a long member as shown in Fig. 1, and a flat member may be used as the base 2, and the direction connecting the light sources 3 and 4 may be the base longitudinal direction x. [Explanation of symbols]

[0121] 1. Measurement equipment 2 Base 3, 4 light source 5. Detection section 6, 90 Focusing lens 12 Imaging Device 12a, 12b, 92, 93, 110 Photosensitive array 13 Processing unit 91 Half Mirror 120 Drive unit

Claims

1. A measurement device that measures a measurement object, A plurality of light sources that emit light beams; A detection unit that detects light and outputs a detection signal; A calculation processing unit that processes the detection signal; a base having a longitudinal direction; The plurality of light sources and the detection unit are provided on the base at intervals in a longitudinal direction of the base, Each of the light sources emits a light beam to a measurement object; the detection unit detects each reflected light of the light beam emitted by each of the light sources in a distinguishing manner, and outputs a detection signal including information on an image formation position of each reflected light in a longitudinal direction of the base; The measurement apparatus according to claim 1, wherein the calculation processing unit calculates a distance from the base to the object to be measured based on the detection signal.

2. The light beams emitted from the respective light sources are reflected at different irradiation positions on the measurement object and detected by the detection unit, 2. The measurement apparatus according to claim 1, wherein the arithmetic processing unit measures unevenness on the surface of the measurement object by calculating distances from the base to the plurality of irradiation positions.

3. The light beams emitted from the respective light sources are reflected at different irradiation positions on the measurement object and detected by the detection unit, 2. The measurement apparatus according to claim 1, wherein the arithmetic processing unit calculates an angle of the surface of the measurement object with respect to the base based on a calculation result of the distance from the base to the two irradiation positions.

4. Each of the plurality of light sources emits light beams having different wavelengths, 2. The measuring device according to claim 1, wherein the detection unit detects reflected light of the light beams emitted by the light sources by distinguishing between different wavelengths.

5. 2. The measuring apparatus according to claim 1, wherein each of said light sources comprises a laser device that generates a laser beam and a focusing lens that focuses the laser beam into a beam.

6. The detection unit includes an imaging device that detects an image formation position in a longitudinal direction of the base; a focusing lens for focusing the reflected light onto the imaging device; The imaging device includes a plurality of photosensitive arrays; 5. The measuring device according to claim 4, wherein reflected light of light rays emitted by different said light sources is detected by different said photosensitive arrays.

7. Further comprising a half mirror for splitting the light incident on the detection unit into two optical paths, The imaging device has two spaced apart photosensitive arrays; 7. The measuring device according to claim 6, wherein reflected light of light beams emitted by the different light sources is split by the half mirror and detected by different photosensitive arrays.

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