Movement speed calculation device and movement speed calculation method

Abstract

The invention provides a movement speed calculation device and a movement speed calculation method, which can calculate the movement speed of a measured object without using transmitted light to the measured object. This movement speed calculation device is provided with: a light quantity distribution signal acquisition unit that acquires, from a light detector that images, using an imaging lens, reflected light including light unevenness from a side surface of a moving object to be measured, a light quantity distribution signal corresponding to images of the reflected light captured at two different times from each other, from a light detector that images the reflected light including light unevenness from the side surface of the moving object to be measured; a movement amount calculation unit that calculates, from the light quantity distribution signals at two different times acquired by the light quantity distribution signal acquisition unit, the amount of movement pixels that move within a difference between the two times; and a speed calculation unit that calculates the moving speed of the object to be measured on the basis of the lateral magnification of the imaging lens, the pixel pitch of the photodetector, the difference value, and the amount of moving pixels.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a moving speed calculation device and a moving speed calculation method. BACKGROUND

[0002] A speed calculation device that measures a moving speed of a measured object in a non-contact manner is disclosed in Patent Literature 1.

[0003] [RELATED ART LITERATURE] [PATENT LITERATURE] [Patent Literature 1] Japanese Patent Laid-Open No. 63-158465 SUMMARY [PROBLEMS TO BE SOLVED BY THE INVENTION] The speed calculation device disclosed in Patent Literature 1 measures a moving speed of a light-transmissive object by transmitting light emitted from a light source through the light-transmissive object. In such a speed calculation device that uses a transmission method, a light source and a polarizing plate or the like are required to be provided on one side sandwiching the light-transmissive object, and on the other hand, a polarizing plate, an imaging optical system, a spatial filter, and a light detector or the like are required to be provided on the other side sandwiching the light-transmissive object. Therefore, the speed calculation device disclosed in Patent Literature 1 can cause the device to be large-sized.

[0004] The present disclosure was completed in order to solve the problem, and has an object to provide a moving speed calculation device that can calculate a moving speed of a measured object without using transmitted light of the measured object.

[0005] [MEANS FOR SOLVING THE PROBLEM] The moving speed calculation device of the present disclosure includes: a light amount distribution signal acquisition section that acquires a light amount distribution signal from a light detector that images reflected light containing light unevenness from a side of a measured object that moves, the light amount distribution signal corresponding to images of the reflected light taken at two times different from each other; a moving amount calculation section that calculates a moving pixel amount within a difference between the two times, based on the light amount distribution signals at the two times different from each other acquired by the light amount distribution signal acquisition section; and a speed calculation section that calculates a moving speed of the measured object, based on a lateral magnification of an imaging lens, a pixel pitch of the light detector, the difference, and the moving pixel amount.

[0006] [EFFECT OF THE INVENTION] According to the present disclosure, a moving speed of a measured object can be calculated without using transmitted light of the measured object. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1A and Figure 1BFIG. 1 is a schematic configuration diagram of a speed measuring device to which the mobile speed calculation device of Embodiment 1 is applied. Figure 1A FIG. 2 is a plan view of the speed measuring device. Figure 1B FIG. 3 is a side view of the speed measuring device, which is obtained when viewed from the downstream side in the moving direction of the object to be measured.

[0008] Figure 2 FIG. 4 is a block diagram of the mobile speed calculation device of Embodiment 1.

[0009] Figure 3 FIG. 5 is a flowchart showing the operation of the mobile speed calculation device of Embodiment 1.

[0010] BRIEF DESCRIPTION OF DRAWINGS 10: speed measuring device 11: light source 12: illumination lens 13: imaging lens 13a: first lens 13b: second lens 13c: aperture 14: light detector 20: mobile speed calculation device 21: light control section 22: light amount distribution signal acquisition section 23: light amount distribution signal storage section 24: movement amount calculation section 25: measurement constant storage section 26: speed calculation section 27: output section 50: object to be measured 51: side surface DETAILED DESCRIPTION Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings.

[0011] Embodiment 1 Use Figures 1A to 3 The mobile speed calculation device 20 of Embodiment 1 will be described.

[0012] First, the structure of the speed measuring device 10 to which the mobile speed calculation device 20 of Embodiment 1 is applied will be described. Figure 1A Figure 1B FIG. 1 is a schematic configuration diagram of the speed measuring device 10 to which the mobile speed calculation device 20 of Embodiment 1 is applied. Figure 1A Figure 1B FIG. 1 is a schematic configuration diagram of the speed measuring device 10 to which the mobile speed calculation device 20 of Embodiment 1 is applied.

[0013] Figure 1A Figure 1B ​​​The illustrated speed measurement device 10 measures the moving speed of a measurement target 50 in a sheet shape in a non-contact manner using an optical method. As the optical method for measuring the moving speed of the measurement target 50 in a non-contact manner, a template matching method, a spatial filtering method, or a laser Doppler method, or the like can be considered. Figure 1A and Figure 1B The arrow A described indicates the moving direction of the measurement target 50. The measurement target 50 moves along the length direction thereof.

[0014] The measurement target 50 is formed of a transparent or translucent material, for example. The measurement target 50 is a transparent film, a transparent sheet, or a transparent substrate, or the like, for example.

[0015] Here, the side surface 51 of the measurement target 50 is a rough surface. This side surface 51 becomes a rough surface by not performing mirror surface processing. Alternatively, the side surface 51 becomes a rough surface by performing rough surface processing. Thus, in the reflected light reflected from the side surface 51, light unevenness corresponding to the surface roughness occurs, and the light intensity of the reflected light increases. The light unevenness refers to a deviation in brightness. At this time, at least the side surface 51 of the measurement target 50 on the side irradiated with light from the light source 11 described later can be a rough surface.

[0016] Further, a pattern formed of ink or the like can be attached to the side surface 51. In this way, by using the side surface 51 to which the pattern is attached, light unevenness corresponding to the density of the pattern occurs in the reflected light, and the light intensity of the reflected light increases.

[0017] As shown in Figure 1A and Figure 1B The speed measurement device 10 includes a light source 11, an illumination lens 12, an imaging lens 13, and a light detector 14, as shown.

[0018] The light source 11 irradiates light toward one of the side surfaces 51 of the moving measurement target 50. The intensity of the light emitted from the light source 11 is constant, for example. The light source 11 is a light emitting diode, a semiconductor laser, or a halogen bulb, or the like, for example.

[0019] The illumination lens 12 makes the light emitted from the light source 11 into parallel light. In addition, the illumination lens 12 illuminates the side surface 51 of the measurement target 50 with the light made into parallel light in a prescribed range and at a prescribed illumination angle. Thus, the light emitted from the light source 11 is irradiated to the side surface 51 of the measurement target 50 via the illumination lens 12.

[0020] The imaging lens 13 receives reflected light from the side surface 51 of the measurement target 50 and images the image plane of the received reflected light on the light detector 14. The imaging lens 13 has a first lens 13a, a second lens 13b, and an aperture 13c, for example.

[0021] The first lens 13a is disposed so that its optical axis is orthogonal to the side surface 51 of the measured object 50. The first lens 13a converges reflected light that is parallel light reflected from the side surface 51.

[0022] The second lens 13b is disposed so that its optical axis is orthogonal to the side surface 51 of the measured object 50. The optical axis of the first lens 13a coincides with the optical axis of the second lens 13b. The second lens 13b makes the chief ray of the reflected light converged by the first lens 13a into parallel light, and images its image plane on the light detector 14.

[0023] The diaphragm 13c is disposed between the first lens 13a and the second lens 13b. The diaphragm 13c is provided at the focal point position of the first lens 13a. Therefore, the diaphragm 13c can make the rays of the reflected light converged by the first lens 13a pass toward the second lens 13b at an opening at which the reflected light becomes a desired light intensity and a desired depth of field.

[0024] The light detector 14 is, for example, an array sensor or a line sensor configured in one dimension, or an array sensor or an image sensor configured in two dimensions. The reflected light including light unevenness corresponding to the surface roughness of the side surface 51 is imaged on the light detector 14. The light detector 14 photographs the imaged reflected light including light unevenness at a time t1 and a time t2. In addition, the light detector 14 outputs light amount distribution signals corresponding to the photographed surfaces at the time t1 and the time t2, respectively. These light amount distribution signals are signals obtained by photoelectrically converting the photographed surfaces, and are distributions corresponding to the light unevenness of the reflected light.

[0025] Further, the time t1 and the time t2 are different times from each other. The elapsed time from the time t1 to the time t2 is a very small time. In addition, Δt denotes the time difference, that is, the difference between the time t1 and the time t2.

[0026] Next, the structure of the moving speed operation device 20 applied to the speed measurement device 10 will be described. Figure 1A The structure of the moving speed operation device 20 applied to the speed measurement device 10 will be described. Figure 1B is a block diagram of the moving speed operation device 20 of Embodiment 1.

[0027] The moving speed operation device 20 corresponds to the central operation processing device of the speed measurement device 10. The moving speed operation device 20 has a light control section 21, a light amount distribution signal acquisition section 22, a light amount distribution signal storage section 23, a moving amount operation section 24, a measurement constant storage section 25, a speed operation section 26, and an output section 27.

[0028] The light control section 21 controls the lighting and extinguishing of the light source 11. In addition, when the light source 11 is lit, the light control section 21 outputs an acquisition instruction signal to the light amount distribution signal acquisition section 22. In addition, the time tl, the time t2, and the difference At are input in advance to the light control section 21.

[0029] When the acquisition instruction signal is received from the light control section 21, the light amount distribution signal acquisition section 22 acquires the light amount distribution signal corresponding to the image plane of the reflected light containing the light unevenness photographed by the light detector 14 at the time tl, the time t2.

[0030] The light amount distribution signal storage section 23 stores the light amount distribution signal of at least the time tl among the light amount distribution signals of the times tl, t2 acquired by the light amount distribution signal acquisition section 22.

[0031] The movement amount operation section 24 acquires the light amount distribution signals of the times tl, t2 from the light amount distribution signal storage section 23. Alternatively, the movement amount operation section 24 acquires the light amount distribution signal of the time tl from the light amount distribution signal storage section 23, and acquires the light amount distribution signal of the time t2 from the light amount distribution signal acquisition section 22. In addition, the movement amount operation section 24 uses a template matching method such as a phase-only correlation method, and operates the movement pixel amount Di moving within the difference At using the light amount distribution signals of the times tl, t2.

[0032] The measurement constant storage section 25 has stored therein in advance the lateral magnification m of the imaging lens 13 and the pixel pitch p of the light detector 14. In addition, the difference At can also be stored in advance in the measurement constant storage section 25.

[0033] The speed operation section 26 acquires the difference At from the light control section 21. The speed operation section 26 acquires the movement pixel amount Di from the movement amount operation section 24. The speed operation section 26 acquires the lateral magnification m of the imaging lens 13 and the pixel pitch p of the light detector 14 from the measurement constant storage section 25. Then, the speed operation section 26 operates the movement speed of the measured object 50 on the basis of the difference At, the movement pixel amount Di, the lateral magnification m, and the pixel pitch p.

[0034] Here, if the movement speed of the measured object 50 is set to v, the speed operation section 26 finds this movement speed v using the following expression (1).

[0035] v = m (p x Di / At)... (1) For example, the speed operation section 26 performs a phase-only correlation process on the two light unevenness images of the times tl, t2. The coordinates of the correlation peak value obtained by this process correspond to the relative positional shift amount between these two light unevenness images. Therefore, the movement speed v of the measured object 50 is found using expression (1).

[0036] Furthermore, as the template matching method, the phase-constrained correlation method is used, but a normalized cross-correlation method, a sum of squared difference method, or a sum of absolute difference method, or the like can be used instead of this method. In addition, a spatial filtering method or a laser Doppler method can be used instead of the template matching method.

[0037] The output section 27 acquires the moving speed of the measured object 50 from the speed operation section 26. In addition, the output section 27 outputs the moving speed of the measured object 50 to a display section or the like.

[0038] Next, the operation of the moving speed operation device 20 will be described using Figure 2 The operation of the moving speed operation device 20 will be described. Figure 2 Figure 3 Figure 3 A flowchart showing the operation of the moving speed operation device 20 of Embodiment 1.

[0039] In step ST11, the lateral magnification m of the imaging lens 13 and the pixel pitch p of the light detector 14 are stored in the measurement constant storage section 25.

[0040] In step ST12, the light control section 21 controls the light source 11. The light source 11 irradiates light toward the side surface 51 of the moving measured object 50 via the illumination lens 12.

[0041] In step ST13, the light control section 21 controls the light amount distribution signal acquisition section 22. The light amount distribution signal acquisition section 22 acquires the light amount distribution signal at time t1 from the light detector 14.

[0042] In step ST14, the light amount distribution signal at time t1 acquired by the light amount distribution signal acquisition section 22 is stored in the light amount distribution signal storage section 23.

[0043] In step ST15, the light control section 21 controls the light amount distribution signal acquisition section 22. The light amount distribution signal acquisition section 22 acquires the light amount distribution signal at time t2 from the light detector 14.

[0044] In step ST16, the movement amount operation section 24 uses each of the light amount distribution signals at time t1 and time t2 to operate the moving pixel amount Δi moving within the difference time Δt.

[0045] In step ST17, the speed operation section 26 operates the moving speed v of the measured object 50 based on the difference time Δt, the moving pixel amount Δi, the lateral magnification m, and the pixel pitch p.

[0046] In step ST18, the output section 27 outputs the moving speed v of the measured object 50 operated by the speed operation section 26. Then, the operation of the moving speed operation device 20 ends.

[0047] The mobile speed calculation device 20 of Embodiment 1 includes: a light amount distribution signal acquisition section 22 that acquires a light amount distribution signal from the light detector 14 that images the reflected light containing light unevenness from the side surface 51 of the moving object to be measured 50 with the imaging lens 13, the light amount distribution signal corresponding to the images of the reflected light taken at two different times t1, t2 from each other; a movement amount calculation section 24 that calculates the movement pixel amount Δi moved within the difference Δt between the two times t1, t2 from the light amount distribution signals at the two different times t1, t2 acquired by the light amount distribution signal acquisition section 22; and a speed calculation section 26 that calculates the moving speed of the object to be measured 50 based on the lateral magnification m of the imaging lens 13, the pixel pitch p of the light detector 14, the difference Δt, and the movement pixel amount Δi. Thus, the mobile speed calculation device 20 can calculate the moving speed of the object to be measured 50 without using the transmitted light with respect to the object to be measured 50. As a result, by applying the mobile speed calculation device 20 to the speed measurement device 10, the speed measurement device 10 can be miniaturized.

[0048] In the mobile speed calculation device 20 of Embodiment 1, the side surface 51 of the object to be measured 50 is a rough surface. Thus, the mobile speed calculation device 20 can increase the light intensity of the reflected light from the side surface 51 because the reflected light from the side surface 51 can contain light unevenness. As a result, the mobile speed calculation device 20 can use the light amount distribution signal with increased signal intensity, and thus can calculate the speed of the object to be measured 50 with high precision.

[0049] In addition, in the mobile speed calculation device 20 of Embodiment 1, the side surface 51 of the object to be measured 50 is provided with a pattern. Thus, the mobile speed calculation device 20 can increase the light intensity of the reflected light from the side surface 51 because the reflected light from the side surface 51 can contain light unevenness. As a result, the mobile speed calculation device 20 can use the light amount distribution signal with increased signal intensity, and thus can calculate the speed of the object to be measured 50 with high precision.

[0050] Further, the present disclosure is capable of deforming or omitting any of the constituent components of the embodiments within the scope of the disclosure.

Claims

1. A mobile speed calculation device, characterized in that, include: The light distribution signal acquisition unit acquires a light distribution signal from a photodetector, which uses an imaging lens to image reflected light containing light inhomogeneity from the side of a moving object being measured. The light distribution signal corresponds to the images of the reflected light taken at two different times. The motion calculation unit calculates the amount of moving pixels within the difference between two different time points based on the light distribution signals acquired by the light distribution signal acquisition unit at two different time points. as well as The speed calculation unit calculates the moving speed of the object being measured based on the lateral magnification of the imaging lens, the pixel pitch of the photodetector, the difference, and the amount of moving pixels.

2. The movement speed calculation device according to claim 1, characterized in that, The side surface of the object being measured is rough.

3. The movement speed calculation device according to claim 1, characterized in that, The side of the object being measured has a pattern attached.

4. A method for calculating movement speed, characterized in that, include: The step of the light distribution signal acquisition unit acquiring a light distribution signal from a photodetector, wherein the photodetector uses an imaging lens to image reflected light containing light inhomogeneity from the side of a moving object to be measured, and the light distribution signal corresponds to the image of the reflected light taken at two different times. The step of the motion calculation unit calculating the amount of moving pixels within the difference between two different times based on the light distribution signals at two different times acquired by the light distribution signal acquisition unit; as well as The speed calculation unit calculates the moving speed of the object being measured based on the lateral magnification of the imaging lens, the pixel pitch of the photodetector, the difference, and the amount of moving pixels.

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