JP7797364B2 - Measuring equipment and elevator systems - Google Patents

Description

The present invention relates to a measurement device and an elevator system, and is suitable for use in a measurement device and an elevator system that calculates information related to elevator movement.

Traditionally, elevators equipped with a passenger car (hereinafter referred to as "elevator car" or "cage") as a moving object have used governor ropes as safety devices to monitor the position and speed of the elevator car. In recent years, non-contact sensors (hereinafter referred to as "position and speed sensors") that measure the position and speed of the elevator car have become known as alternatives to governor ropes.

For example, Patent Document 1 discloses an optical position and speed sensor that uses an image sensor installed on the elevator car to capture images of structures within the elevator shaft and measure the position and speed of the elevator car. Non-contact measurement devices such as the position and speed sensor disclosed in Patent Document 1 eliminate the need for long structures such as governor ropes, which has the advantage of improving installation and maintainability, and also has the advantage of eliminating measurement errors due to slippage.

Patent document 2 also discloses an imaging system that uses a phase plate to generate a blurred image, and then performs deconvolution processing in an image processing device to obtain a blur-free, high-resolution image with a wide depth of field.

International Publication No. 2019/239536 Japanese Patent Application Laid-Open No. 2022-71235

In the general structure of image sensors in conventional technology, each pixel of the image sensor has a light-shielding structure around the light-receiving area (hereinafter referred to as the "pixel aperture"). In this case, an image sensor with a narrow pixel aperture cannot properly recognize patterns that are smaller than the pixel, posing a problem of poor pattern matching between captured images. For example, when vibration occurs in the left-right direction due to external disturbances, the image position sampled by the pixel aperture may differ before and after pattern matching, which is one factor that reduces the measurement accuracy and robustness of the car's position and speed.

The present invention has been made in consideration of the above points, and proposes a measurement device and elevator system that can measure the position and speed of an elevator car with high accuracy and high robustness against car displacement based on the imaging results of scattered light reflected from a stationary structure, even if the stationary structure (guide rail) being measured has a brightness pattern (reflected/scattered brightness pattern) in which the image formed by light diffusely reflected (scattered light) from the stationary structure is finer than the pixels of an optical sensor.

To solve these problems, the present invention provides a measurement device that is installed on an elevator car traveling in a hoistway and measures at least one of the distance traveled or the speed of the elevator car. The measurement device includes: a light transmitting unit that transmits light that illuminates stationary structures positioned in the hoistway along the direction of movement of the elevator car; an imaging unit that focuses light scattered from the stationary structures by passing the light through a focusing lens onto an imaging surface; an imaging unit that captures the optical signals of the scattered light that are imaged on the light receiving units of multiple pixels that make up the imaging surface, converts them into electrical signals, and images the resulting image; and an image processing unit that calculates and transmits at least one of the distance traveled or the speed of the elevator car based on the electrical signals converted by the imaging unit. The imaging unit is configured so that when the scattered light incident on the light receiving units of each pixel on the imaging surface is reflected back onto the stationary structure, no gaps are created between pixels with different scattering areas.

In order to solve this problem, the present invention provides an elevator system comprising: an elevator car that moves in a hoistway; a guide rail arranged in the hoistway along the direction of movement of the elevator car; an elevator control unit that controls the operation of the elevator car; and a measurement device installed in the elevator car that measures at least one of the distance traveled or the speed of the elevator car. The measurement device comprises: a light transmitting unit that transmits light that illuminates the guide rail; an imaging unit that focuses light scattered from the guide rail by passing the light through a focusing lens onto an imaging surface; an imaging unit that takes in optical signals of the scattered light that are imaged on the light receiving units of multiple pixels that make up the imaging surface and converts them into electrical signals to form an image; and an image processing unit that calculates and transmits at least one of the distance traveled or the speed of the elevator car based on the electrical signals converted by the imaging unit. The imaging unit is configured so that when the scattered light incident on the light receiving units of each pixel on the imaging surface is pulled back onto the guide rail, there are no gaps between pixels with different scattering areas.

According to the present invention, the position and speed of an elevator car can be measured with high accuracy and with high robustness against car displacement based on the imaging results of scattered light reflected by stationary structures.

1 is a diagram showing a configuration example of an elevator system 10 according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating an example of the internal configuration of a measurement device 110. 1 is a bird's-eye view showing the positional relationship between the optical transmitting unit 210, the imaging unit 220, and the imaging unit 230 in the measuring device 110 and the guide rail 140. FIG. 4 is a conceptual diagram showing the positional relationship between the imaging surface of the imaging unit 230 and an image 410 of the reflected/scattered luminance pattern 310 formed on the imaging surface by the imaging unit 220. FIG. 3A and 3B are conceptual diagrams for explaining the optical performance achieved by the imaging unit 220. FIG. FIG. 1 is a conceptual diagram (part 1) illustrating the effect of improving robustness against displacement of the elevator car 120 using the measurement device 110. FIG. 10 is a conceptual diagram (part 2) illustrating the effect of improving robustness against displacement of the elevator car 120 using the measurement device 110. FIG. 7 is a diagram showing an example of the internal configuration of an imaging unit 720 in a measurement apparatus 710 according to a second embodiment of the present invention. 10A and 10B are conceptual diagrams illustrating the configuration and effect of a phase plate 724. FIG. 10 is a diagram showing an example of the internal configuration of an imaging unit 920 in a measurement apparatus 910 according to a third embodiment of the present invention. FIG. 10 is a diagram showing an example of the internal configuration of an imaging unit 1020 in a measurement apparatus 1010 according to a fourth embodiment of the present invention. FIG. 11 is a diagram showing an example of the internal configuration of an imaging unit 1120 in a measurement apparatus 1110 according to a fifth embodiment of the present invention. 11A and 11B are conceptual diagrams illustrating the configuration and effect of a microlens array 1123.

Embodiments of the present invention will be described in detail below with reference to the drawings.

The embodiments of the present invention described in detail below relate to a measurement device that uses a measurement unit (optical transmitter, imaging unit, and image capture unit) to measure information related to the movement of a moving object (position, movement distance, speed, acceleration, etc.) at high speed and with high accuracy, and to an elevator system, etc., where the stationary structure (guide rail) being measured has a brightness pattern (reflected/scattered brightness pattern) in which the image formed by light diffusely reflected (scattered light) from the stationary structure is finer than the pixels of the optical sensor, and the position and speed of the elevator car are measured with high accuracy and robustness based on the results of capturing the scattered light reflected from the stationary structure. However, the present invention is not limited to the embodiments described below.

The measuring device according to each embodiment of the present invention, described in detail below, is mounted at a predetermined installation position on an elevator car and measures information related to the movement of the elevator car along the path (travel path) that guides the elevator car (specifically, at least one of the elevator car's position (travel distance), speed, acceleration, and vibration). For example, in response to a gate signal generated by the control unit, the measuring device emits (transmits) light from the optical transmitter toward the surface of a stationary structure (e.g., a guide rail, the inner wall surface of the travel path, etc.) that has artificial polishing scratches, which is the subject of the measurement. The measuring device then directs light reflected from the surface of the stationary structure (which may include specularly reflected light and diffusely reflected light; hereinafter, referred to as "scattered light") via the imaging unit onto the imaging surface of the imaging unit, which photoelectrically converts the optical signal into an electrical signal. The measuring device then measures information related to the movement of the elevator car in the image processing unit based on an image generated from the converted electrical signal. Furthermore, the measuring device transmits information related to the elevator car's movement to an elevator car control unit (mobile body control unit), which controls the elevator car's operation or safety devices. The mobile body control unit then controls the elevator car's operation and safety devices based on the information related to the elevator car's movement calculated by the measuring device.

In this specification, "light" refers to electromagnetic waves, and specifically includes visible light, microwaves, terahertz waves, infrared rays, ultraviolet rays, X-rays, etc.

Furthermore, in the following description, when describing elements of the same type without distinction, the common portion (the portion excluding the branch number) of the reference number including the branch number may be used, and when describing elements of the same type with distinction, the reference number including the branch number may be used. For example, when describing a measurement device without any particular distinction, it may be written as "measurement device 110," whereas when describing individual measurement devices 110 with distinction, it may be written as "measurement device 110-a," "measurement device 110-b," etc.

(1) First Embodiment (1-1) Configuration of Elevator System 10 Fig. 1 is a diagram showing an example of the configuration of an elevator system 10 according to a first embodiment of the present invention. The first embodiment is an embodiment that illustrates a concept common to each embodiment of the present invention, and in the explanations of the other embodiments (second to fifth embodiments) described later, detailed explanations of the configuration common to the first embodiment will be omitted.

As shown in FIG. 1, the elevator system 10 is configured to include a measurement device 110 (individually 110-a and 110-b) mounted on top of an elevator car 120 that ascends and descends within a hoistway (pathway for a moving object) in a building (not shown). In addition to the measurement device 110, the elevator system 10 also includes components such as the elevator car 120, an elevator control unit 130, and guide rails 140 (individually 140-a and 140-b), but at least one of these components may be included in the measurement device 110.

The measuring device 110 outputs signal information useful for controlling the operation of the elevator car 120 (e.g., signal information related to the position, speed, or acceleration of the elevator car 120) to the elevator control unit 130. The location of the measuring device 110 is not limited to the top of the elevator car 120, but may also be located, for example, on the side or bottom of the elevator car 120 (details will be described later). The measuring device 110 shown in FIG. 1 has a redundant configuration achieved by duplication with measuring device 110-a and measuring device 110-b, but the configuration of the measuring device 110 according to this embodiment is not limited to a duplex configuration and may be a single-system configuration without redundancy, or a triplex or more redundant configuration.

The elevator control unit 130 uses the signal information output from the measurement device 110 to control the operation of the elevator car 120 and safety devices, etc.

The guide rail 140 is an example of a stationary structure that serves as a reference when measuring the relative distance and angle of the measurement device 110, and is located within the elevator shaft. The guide rail 140 is located within the elevator shaft along the direction of movement of the moving object (the y-axis direction in Figure 1), and comes into contact with the guide rollers of the elevator car 120 to support the movement of the moving object (elevator car 120).

In the following explanation, a coordinate system is used to indicate the optical axis direction and illumination direction of the measurement device 110. Specifically, as shown in Figure 1, the coordinate system is defined by defining the direction of movement of the moving body as the y-axis direction, the direction perpendicular to the imaging surface (in Figure 1, the top surface of the convex portion of the guide rail 140) as the z-axis direction, and the direction perpendicular to both the y-axis and z-axis as the x-axis direction. Unless otherwise specified, the terms x-direction, y-direction, and z-direction can be considered to be synonymous with the x-axis, y-axis, and z-axis directions.

Figure 2 is a diagram showing an example of the internal configuration of the measurement device 110. As shown in Figure 2, the measurement device 110 is composed of an optical transmitter 210, an imaging unit 220, an image capture unit 230, and an image processor 240. Note that in Figure 2, the optical path is indicated by a dashed line with an arrow, and the path of the electrical signal is indicated by a solid line with an arrow.

The optical transmitter 210 has a light source (not shown) and is positioned to emit light toward the surface of the guide rail 140, which is the subject of the image. The light source of the optical transmitter 210 may be a temporally and spatially incoherent light source such as an LED (Light Emitting Diode) or halogen lamp, or a temporally and spatially coherent light source such as a laser light source. Furthermore, multiple optical transmitters 210 may be provided to emit light toward the guide rail 140 from both the left and right directions, for example.

The imaging unit 220 is configured as an optical system that forms an image of the scattered light from the surface of the guide rail 140, which is emitted from the optical transmitter 210 toward the surface of the guide rail 140, on the imaging surface of the imaging unit 230. The imaging unit 220 can be, for example, a single lens made of glass or resin, a set of multiple lenses, or a concave mirror. Details will be described later with reference to Figures 4 to 7, but the imaging surface of the imaging unit 220 is made up of multiple pixels. The imaging unit 220 then outputs an optical signal indicating the luminance distribution of the light that has been imaged on the imaging surface including the multiple pixels to the imaging unit 230.

The imaging unit 230 converts the optical signal from the imaging unit 220 (an optical signal indicating the scattered luminance distribution on the surface of the guide rail 140) that is imaged on an imaging surface including multiple pixels into an electrical signal corresponding to the pixel luminance, and transmits the converted electrical signal to the image processing unit 240 as an image signal in synchronization with a timing signal indicating the start and end times of imaging transmitted from the image processing unit 240. The imaging unit 230 may be, for example, a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The imaging unit 230 may also be a two-dimensional area sensor or a one-dimensional line sensor capable of spatial resolution in the ascending and descending direction of the elevator car 120.

The measuring device 110 may also include a wavelength-selective filter, such as a bandpass filter, in addition to the imaging unit 220, in the path of the emitted light from the optical transmitter 210 and its scattered light to remove external light other than that of the desired wavelength. The measuring device 110 may also include a window or the like in the path of the incident light and scattered light to protect the measuring device 110 from sand, dust, and other particles entering the interior.

The image processing unit 240 performs image processing on the image signal (an electrical signal converted from the optical signal focused on the imaging surface) received from the imaging unit 230, and performs processing such as pattern matching between time-series captured images based on the captured images generated by this image processing to calculate information related to the movement of the elevator car 120 (specifically, the measurement results of at least one of the movement distance (movement amount) or speed of the elevator car 120; hereafter referred to as car movement-related information), and transmits this information to the elevator control unit 130.

The image processing unit 240 may be specifically configured with an information processing storage medium such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), or microcontroller, or may be configured with logic circuit elements such as an FPGA (Field-Programmable Gate Array). The image processing unit 240 converts the car movement-related information according to a communication protocol that can be received by the elevator control unit 130 (e.g., a protocol such as CAN (Controller Area Network) communication or USB (Universal Serial Bus) communication), and outputs the converted signal information to the elevator control unit 130. The method of output to the elevator control unit 130 may be a connector for connecting an electrical cable, or an antenna for wireless communication.

Figure 3 is an overhead view showing the positional relationship between the optical transmitter 210, imaging unit 220, and imaging unit 230 in the measuring device 110 and the guide rail 140.

As shown in FIG. 3, light emitted from the optical transmitter 210 toward the guide rail 140 is diffusely reflected by the guide rail 140 and focused onto the imaging unit 230 by the imaging unit 220. While FIG. 3 shows multiple optical transmitters 210 emitting light toward the guide rail 140, light may be emitted from a single optical transmitter 210. The imaging unit 220 forms an image of a reflected/scattered luminance pattern 310 on the convex portion of the guide rail 140 on the light receiving surface of the imaging unit. The reflected/scattered luminance pattern 310 corresponds to the irregularities, etc., on a specific surface of a stationary structure (in the case of FIG. 3, the convex portion of the guide rail 140) imaged by the imaging unit 230. In this embodiment, the image formed by the scattered light diffusely reflected from the reflected/scattered luminance pattern 310 may be smaller in size than a pixel of the optical sensor (one of the multiple pixels 420 constituting the light receiving surface of the imaging unit 230).

The surface imaged by the imaging unit 230 is not limited to the top surface of the convex portion of the guide rail 140 as shown in Figure 3, but other surfaces of the guide rail 140 may be selected. Specifically, for example, the side surface of the convex portion of the guide rail 140 may be imaged, or the flange surface of the guide rail 140 where the bolt is fastened may be imaged.

(1-2) Basic Configuration of Imaging Unit 220 The configuration of the imaging unit 220 will be described in detail.

Figure 4 is a conceptual diagram showing the positional relationship between the imaging surface of the imaging unit 230 and the image 410 of the reflected/scattered luminance pattern 310 formed on the imaging surface by the imaging unit 220. The problem that the measurement device of the present invention aims to solve will be explained in detail using Figure 4. Figure 4 shows the time series change from Figure 4(a) to Figure 4(b). Specifically, Figures 4(a) and 4(b) correspond to the time periods before and after the elevator car 120 is displaced in the x-axis direction or y-axis direction relative to the guide rail 140. Note that while Figure 4 shows an example in which the imaging unit 230 is a two-dimensional area sensor, the basic configuration remains the same even if the imaging unit 230 is a one-dimensional line sensor.

The light receiving surface of the imaging unit 230 is composed of multiple pixels 420 arranged in an array. Each pixel 420 includes a light receiving section 430 composed of an element such as a photodiode that receives light within the pixel and converts it into an electrical signal. As indicated by the diagonal lines in Figure 4, the light receiving section 430 is limited to a partial area of the pixel 420. Wiring may be arranged in areas of the pixel 420 other than the light receiving section 430 to amplify the electrical signal or output it to the outside.

When the elevator car 120 is displaced in the x-axis or y-axis direction relative to the guide rail 140, the image 410 of the reflected/scattered luminance pattern 310 is also displaced in the x-axis or y-axis direction, as shown in Figure 4(a) to Figure 4(b). In this case, a bright portion of the image 410 that was incident on the light receiving unit 430 in Figure 4(a) before the displacement may move away from the light receiving unit 430 in Figure 4(b) after the displacement, or a bright portion that was not incident on the light receiving unit 430 in Figure 4(a) before the displacement may enter the light receiving unit 430 in Figure 4(b) after the displacement. As a result, when the light receiving section 430 in the imaging section 230 is narrow and an image 410 of the reflected/scattered luminance pattern 310, which is finer than the pixel 420, is captured, the pattern of the image captured by the imaging section 230 changes significantly before and after displacement, which is one factor that reduces the accuracy with which the image processing section 240 obtains information related to the movement of the elevator car 120 (more specifically, the accuracy of pattern matching between captured images).

The imaging unit 220 of the measurement device 110 according to this embodiment achieves optical performance that can solve the above-mentioned problems, and is described in detail below with reference to Figures 5 to 7.

Figure 5 is a conceptual diagram illustrating the optical performance achieved by the imaging unit 220. The imaging unit 220 focuses light scattered from the guide rail 140 onto the imaging surface of the imaging unit 230.

This section explains the distribution of irradiance (point spread function 510) on the image plane obtained from a single point light source placed on the object plane in the imaging unit 220.

The imaging unit 220 is configured so that the scattering region on the guide rail 140 of the scattered light rays incident on the light receiving unit 430 of each of the multiple pixels 420 covers the entire imaging target area. In other words, the imaging unit 220 is configured so that when the scattered light collected by the imaging unit 220 and incident on the light receiving unit 430 of each pixel 420 on the imaging surface is returned onto the surface of the guide rail 140, the scattering region (hereinafter referred to as the inverse image 520 of the light receiving unit 430) does not produce gaps between different pixels. Specifically, the imaging unit 220 is configured so that the width of the inverse image 520 of the light receiving unit 430 in each pixel 420 is approximately equal to the value obtained by multiplying the pixel pitch W _PIX of the imaging unit 230 by the reciprocal of the optical magnification M of the imaging unit 220. With this configuration, even if the elevator car 120 is displaced relative to the guide rail 140, it is possible to eliminate changes in the pattern of the image captured by the imaging unit 230 before and after the movement.

In this embodiment, as an example of a configuration in which the scattering region on the guide rail 140 of the scattered light rays covers the entire imaging target region by the imaging unit 220, a configuration in which the spread of the point spread function 510 in the imaging unit 220 is of a predetermined size is disclosed. By widening the width of this point spread function 510, an imaging unit 220 is realized that expands the region on the object surface detected by the light receiving unit 430 of the imaging unit 230.

In this embodiment, the point spread function 510 of the imaging unit 220 is determined so that the inverse image 520 of the light receiving unit 430 on the object surface (for example, the top surface of the convex portion of the guide rail 140) obtained by inverse ray tracing coincides with a pixel or is larger than a pixel. In other words, the imaging unit 220 is selected so as to satisfy the relationship shown in the following equation 1.
In Equation 1, W _PSF is the spread width of the point spread function 510 in the imaging unit 220, W _PIX is the pitch of the pixels 420 in the imaging unit 230, and W _PD is the width of the light receiving unit 430 in the imaging unit 230. Note that the spread width W _PSF of the point spread function is the full width determined by, for example, the RMS (Root Mean Square) method.

On the other hand, if the spread width of the point spread function 510 is large and the image from the inverse image 520 at the object plane position spreads to multiple or more pixels 420, the resolution of the captured image of the reflected/scattered luminance pattern 310 captured by the imaging unit 230 decreases, and the resolution when the image processing unit 240 measures the movement distance of the elevator car 120 by comparing multiple captured images decreases. Therefore, ideally, the accuracy of pattern matching between captured images is best when the width W _PSF +W _PD of the inverse image 520 is equal to the pixel pitch W _PIX of one pixel. Therefore, by making the spread width W _PSF of the point spread function 510 satisfy the relationship of the following equation 2, an upper limit can be set to prevent the image from the inverse image 520 from spreading to multiple or more pixels 420.

The imaging unit 220 may be configured asymmetrically in the horizontal direction (x direction) and the car travel direction (y direction) so as to adjust the spread width of the point spread function in each of the horizontal and car travel directions. Specifically, for example, when the spread width of the point spread function 510 in the horizontal direction (x direction) is W _PSF (x), the pitch of the pixels 420 is W _PIX (x), the width of the light receiving unit 430 is W _PD (x), the spread width of the point spread function 510 in the car travel direction (y direction) is W _PSF (y), the pitch of the pixels 420 is W _PIX (y), and the width of the light receiving unit 430 is W _PD (y), the asymmetric imaging unit 220 may be selected so as to satisfy the following equations 3 to 6.

Figures 6 and 7 are conceptual diagrams (part 1 and part 2) that explain the effect of improving robustness against the displacement of the elevator car 120 using the measurement device 110. Figure 7 is a conceptual diagram of the configuration of this embodiment in which the imaging unit 220 satisfies the above formula 1, while Figure 6 is a conceptual diagram, for comparison with Figure 7, in which it is assumed that the imaging unit 220 does not satisfy the above formula 1.

(a) and (b) in Figures 6 and 7 show example frames before and after displacement of the elevator car 120 relative to the guide rail 140. Also, in each of these figures (Figures 6(a), (b), and 7(a), (b)), on the left side, an inverse image 520 of the light receiving unit 430 at the object plane position, formed by the imaging unit 220, is depicted superimposed on the reflected/scattered luminance pattern 310 on the object plane (guide rail 140), and on the right side, the output 610 from each pixel is displayed in an array. The output 610 is displayed darker for each pixel 420 in the light receiving unit 430 when the proportion of images (feature points) formed by the reflected/scattered luminance pattern 310 is high, and lighter when this proportion is low.

If the imaging unit 220 does not satisfy Equation 1, when the fine reflection/scattering luminance pattern 310 is captured, and the elevator car 120 is displaced relative to the guide rail 140 due to vibration or other reasons, the inverse image 520a of the light receiving unit 430 may shift in the translational direction, as shown in FIG. 6, and feature points observed in the frame before the displacement (left side of FIG. 6(a)) may disappear in the frame after the displacement (left side of FIG. 6(b)). As a result, when the image processing unit 240 performs image processing on the image signal received from the imaging unit 230, the pattern in the captured image (pattern of pixel-by-pixel output 610a) changes significantly (see the right side of FIGS. 6(a) and 6(b)), which is one factor that reduces the accuracy of the "information related to the movement of the elevator car 120" calculated by the image processing unit 240.

In contrast, when the imaging unit 220 satisfies Equation 1, as shown in Figure 7, the inverse image 520b of the light receiving unit 430 is wider than the inverse image 520a when the imaging unit 220 does not satisfy Equation 1 (as in Figure 6). This eliminates gaps between the areas of the inverse images 520b, making it possible to smooth and capture the fine reflection/scattering luminance pattern 310. Therefore, even if the elevator car 120 is displaced relative to the guide rail 140 due to vibration or other factors, causing the inverse image 520b of the light receiving unit 430 to shift in the translational direction (see the left side of Figures 7(a) and (b)), the pattern in the smoothed captured image (the pattern of pixel-by-pixel output 610b) is unlikely to lose its characteristic features, and differences in the displacement between frames before and after the displacement are unlikely to occur (see the right side of Figures 7(a) and (b)). Therefore, in the measuring device 110 according to this embodiment, by having the imaging unit 220 satisfy Equation 1, the image processing unit 240 can perform image processing with high accuracy on the image signal received from the imaging unit 230, and the configuration makes it easy to maintain the accuracy of the "information related to the movement of the elevator car 120."

As described above, in the measuring device 110 according to the first embodiment and the elevator system 10 including the measuring device 110, the measuring device 110 measures signal information useful for controlling the operation of the elevator car 120 (e.g., signal information related to the position, speed, acceleration, etc. of the elevator car 120) using an image captured by irradiating the guide rail 140, which is a stationary structure, with scattered light diffusely reflected, to measure the signal information. Even if the stationary structure has a luminance pattern (reflected/scattered luminance pattern) in which the image formed by the light diffusely reflected (scattered light) from the stationary structure is finer than the pixels of the optical sensor, the measuring device 110 configures the imaging unit 220 so that no gaps are generated between multiple different pixels (each region of width MW _PIX shown in FIG. 5 ) in each scattering region (each region of the inverse image 520 shown in FIG. 5 ) where the scattered light incident on the light receiving unit 430 of the pixel 420 in the imaging unit 230 is scattered on the stationary structure. With this type of measurement device 110, even if the elevator car 120 is displaced relative to the guide rail 140 due to vibration or the like, causing the inverse image 520b of the light receiving unit 430 to shift in the translational direction, it is possible to prevent the disappearance of minute feature points of the reflected/scattered luminance pattern 310 from occurring in the pattern of the captured image obtained by smoothing each pixel, thereby enabling the image processing unit 240 to match patterns before and after the displacement, and to measure signal information useful for controlling the operation of the elevator car 120 without sacrificing accuracy. This effect can also be obtained in other embodiments described below.

In the following embodiments, specific imaging units that realize the concept of the imaging unit 220 described in the first embodiment will be described, with various basic configurations. The imaging units shown in the following embodiments, except for the fifth embodiment, can be considered as one example of realizing the imaging unit 220 in the first embodiment, and the figures used in the description of the first embodiment (Figures 1 to 7) are, in principle, applicable to all embodiments. However, the concepts shown in Figures 4 to 7 do not apply to the fifth embodiment, which does not have the feature of creating and capturing a blurred image.

(2) Second Embodiment Fig. 8 is a diagram showing an example of the internal configuration of an imaging unit 720 in a measuring apparatus 710 according to a second embodiment of the present invention. The measuring apparatus 710 according to the second embodiment includes the imaging unit 720 as an example of the imaging unit 220 in the measuring apparatus 110 according to the first embodiment, and includes an imaging unit 730 as an example of the imaging unit 230. Note that the configuration of the measuring apparatus 710 other than the above is the same as that of the measuring apparatus 110 according to the first embodiment, and therefore detailed description thereof will be omitted.

The measurement device 710 according to the second embodiment is characterized by being equipped with a robust imaging unit 720 that can keep the imaging magnification of the imaging unit 730 unchanged despite shaking of the elevator car 120 in the z-axis direction, and that keeps the change in the spread width of the point spread function sufficiently small despite shaking in the z-axis direction.

Furthermore, this imaging unit 720 is characterized by being able to keep the change in the spread width of the point spread function sufficiently small in response to shaking of the elevator car 120 in the z-axis direction, even when the aperture width of the diaphragm 722 is greatly widened, and being able to obtain a sufficiently high amount of light for the image formed on the imaging unit 730, thereby making the captured image bright.

Note that the configuration of the measurement device 710 according to the second embodiment, other than the imaging unit 720, is the same as that of the first embodiment, and therefore detailed description will be omitted.

As shown in FIG. 8, the imaging unit 720 forms an image of the scattered light reflected by the guide rail 140 on the imaging unit 730. Specifically, the imaging unit 720 is configured with an objective lens 721 (first lens), an aperture 722, a condenser lens 723 (second lens), and a phase plate 724.

The objective lens 721 is disposed opposite the guide rail 140 and focuses the scattered light scattered by the guide rail 140. The aperture 722 limits the amount of scattered light focused by the objective lens 721. The focusing lens 723 is disposed between the aperture 722 and the imaging unit 730 and focuses the scattered light whose amount has been limited by the aperture 722, and sends the focused scattered light toward the imaging surface of the imaging unit 730.

The phase plate 724 is installed, for example, at the aperture position of the diaphragm 722, and applies a predetermined aberration to the light rays that form an image on the imaging unit 730. This aberration has the effect of widening the point spread function in the imaging unit 730 and keeping small changes in the shape of the point spread function in response to displacement of the guide rail 140 and imaging unit 730 in the optical axis direction.

Furthermore, as shown in FIG. 8, the imaging unit 720 has a telecentric optical arrangement on the object side (guide rail 140 side) to eliminate the effect of changes in magnification when the subject (detection target) guide rail 140 moves in the z-axis direction relative to the elevator car 120, and is configured to form an image on the imaging unit 730 using two or more lenses to suppress geometric aberrations that occur in the imaging unit 730. Furthermore, the imaging unit 720 may also have a telecentric optical arrangement on the image side (imaging unit 730 side), in which case it serves to widen the dimensional tolerance in the z-axis direction (mounting tolerance in the z-axis direction) when installing the imaging unit 730.

In other words, in the measurement device 710, the center of the imaging surface of the imaging unit 730, the optical axis of the condenser lens 723, the center of the aperture 722, and the optical axis of the objective lens 721 are arranged so that they are aligned on the same straight line, and the aperture 722 is arranged at the focal position of the objective lens 721 on the imaging unit 730 side, and at the focal position of the condenser lens 723 on the objective lens 721 side.

Figure 9 is a conceptual diagram explaining the configuration and effect of the phase plate 724. Figure 9(a) shows a front view of the phase plate 724, and Figure 9(b) shows an image of the optical path near the phase plate 724.

Conventionally, phase plates have been used to minimize changes in point spread distribution with respect to displacement of the object plane and image plane along the optical axis, thereby generating blurred captured images. For example, the aforementioned Patent Document 2 discloses a phase plate used for such purposes.

As shown in Figure 9, the phase plate 724 provided in the imaging unit 720 of the second embodiment has a concave-convex shape formed of a plurality of annular grooves 810, for example, axially symmetrical with respect to the optical axis. Note that the number of annular grooves 810 is not particularly limited.

In each annular groove of the phase plate 724, a light ray that passes through a surface whose normal is parallel to the optical axis 840, i.e., the bottom of a concave portion or the apex of a convex portion where the surface inclination is at its extreme value (light ray 821 shown by the dashed line in Figure 9(b)), is incident on the focal point 830 of the optical system when the phase plate 724 has no irregularities, without generating aberrations.

On the other hand, in each annular groove of the phase plate 724, light rays incident on a surface whose normal is inclined with respect to the optical axis are refracted, resulting in aberration. Specifically, for example, light ray 822, shown by the dotted line in FIG. 9(b), is refracted by the phase plate 724 in a direction approaching the optical axis, becoming a converging light ray. This converging light ray is imaged by the condensing lens 723 at position 831 in front of the focal point 830. Also, for example, light ray 823, shown by the dashed line in FIG. 9(b), is refracted by the phase plate 724 in a direction away from the optical axis, becoming a diverging light ray. This diverging light ray is imaged by the condensing lens 723 at position 832 behind the focal point 830. In this way, light rays 822 and 823 that pass through the inclined surface of the phase plate 724 are incident at positions shifted in front of and behind the focal point, resulting in blurring of the point spread function.

The shape of the phase plate 724 is determined, for example, from the longitudinal aberration Δz that the phase plate 724 causes in the light beam. The longitudinal aberration Δz is defined by the distance between the focal point 830 and the point where the light beam, to which aberration has been imparted by the phase plate 724, intersects with the optical axis (the aforementioned position 831 or position 832).

In the imaging unit 720, the wavefront aberration W(r) imparted to the light rays by the phase plate 724 is determined so that the longitudinal aberration Δz is uniformly distributed within the expanded range of the depth of field determined by the displacement of the elevator car 120 in the optical axis direction; specifically, for example, so that the longitudinal aberration Δz is greater than the amplitude of the vibration of the elevator car 120. Here, the wavefront aberration W(r) is the wavefront aberration imparted to the light rays crossing the position r of the exit pupil plane, and is defined as a function of the position r of the exit pupil plane.

When the determined wavefront aberration W(r) is realized by a parallel, flat, transparent optical element, the sag amount Z(r) of the phase plate 724 is designed to satisfy the following equation 7.
In Equation 7, n is the refractive index of the material of the optical element.

Here, we will explain in detail how the measuring device 710 according to the second embodiment differs from the imaging system of Patent Document 2, which was presented as a prior art technique using a phase plate. Patent Document 2 discloses a configuration in which a phase plate is used to uniformize blur, and then deconvolution processing is performed in an image processing device, ultimately obtaining a blur-free, high-resolution image with a wide depth of field. In contrast, in the second embodiment, obtaining a blur-free image is not necessary, and the measuring device 710 does not perform the aforementioned deconvolution processing on the captured image in which the point spread function 510 is given a certain spread determined by Equations 1 and 2 (i.e., the captured image of the blurred point spread function). The measuring device 710 then calculates the movement distance of the elevator car 120 between times by having the image processing unit 240 directly perform matching determination processing, such as pattern matching, between the captured images acquired at different times.

Thus, the measurement device 710 according to the second embodiment eliminates the need for deconvolution processing to obtain a high-resolution image without blur, and by utilizing the blur, can realize a measurement device that is robust against displacement of the elevator car 120 in the left-right or depth direction. Furthermore, by using a phase plate 724 in the imaging unit 720, the measurement device 710 according to the second embodiment can impart a phase distribution to the light rays passing through the aperture surface and equalize the blur of the point image due to focus deviation, which is expected to have the effect of improving the detection efficiency of the reflected/scattered luminance pattern 310 having fine unevenness.

While the second embodiment has been described using an example of a phase plate with annular grooves (annular phase plate), the shape that can be used for the phase plate 724 is not limited to annular. For example, it is also possible to use a band-shaped phase plate that has curvature only in the x direction (horizontal direction) and has cylindrical concave-convex grooves that are translationally symmetric in the y direction (car travel direction) arranged in a band-like pattern in the x direction. By using such a band-shaped phase plate, the phase plate 724 can impart different optical performance to the horizontal direction (x direction) and the car travel direction (y direction) of the imaging unit 720 (asymmetric configuration). By using such an asymmetric configuration, it is possible to realize an imaging unit 720 that satisfies the conditions in each direction according to Equations 3 to 6, even if the pixels 420 and the light receiving units 430 are not square but, for example, rectangular.

(3) Third Embodiment Fig. 10 is a diagram showing an example of the internal configuration of an imaging unit 920 in a measurement apparatus 910 according to a third embodiment of the present invention. The measurement apparatus 910 according to the third embodiment includes the imaging unit 920 as an example of the imaging unit 220 in the measurement apparatus 110 according to the first embodiment, and includes an imaging unit 930 as an example of the imaging unit 230. Note that the configuration of the measurement apparatus 910 other than the above is the same as that of the measurement apparatus 110 according to the first embodiment, and therefore detailed description thereof will be omitted.

As shown in FIG. 10, the imaging unit 920 includes a lens 921 and an aperture 922, and forms an image of the scattered light reflected by the guide rail 140 on the imaging unit 930. Specifically, the lens 921 is disposed opposite the guide rail 140 and collects the scattered light scattered by the guide rail 140. The aperture 922 limits the amount of scattered light collected by the lens 921 and sends it toward the imaging surface of the imaging unit 930.

The measurement device 910 is positioned so that the guide rail 140 is located at a defocus position shifted in the optical axis direction from the conjugate plane position (focus position) of the imaging unit 920 on the imaging unit 930 (imaging plane). In Figure 10, to clearly illustrate the defocus position, the position of the guide rail 140 is shown as moving by the amount of defocus. However, in reality, the guide rail 140 is a stationary structure in a fixed position, and therefore the position of the entire measurement device 910 (or the imaging unit 920 and imaging unit 930 within the measurement device 910) is adjusted. This type of illustration is also true for Figure 11, which will be described in the fourth embodiment.

Figure 10 shows the point spread function when the guide rail 140 is located at the in-focus position and the point spread function when the guide rail 140 is located at the defocus position. As is clear from the point spread function shown in Figure 10, the spread of the point spread function is small at the in-focus position, but by shifting and installing the measurement device 910 so that the guide rail 140 is at the defocus position, the spread of the point spread function can be increased. More specifically, by shifting it to the defocus position, the spread of the point spread function can be determined so as to satisfy the above-mentioned equations 1 and 2.

Furthermore, in the third embodiment, the lens 921 may be a cylindrical lens with curvature in only one direction, or a toric lens with curvature in both directions but with different curvatures, thereby imparting different optical performance to the horizontal direction (x direction) of the imaging unit 920 and the car travel direction (y direction). By using such an asymmetric configuration, it is possible to realize an imaging unit 920 that satisfies the conditions in each direction according to Equations 3 to 6, even if the pixels 420 and light receiving units 430 are not square but, for example, rectangular.

The measuring device 910 according to the third embodiment configured as described above can achieve the desired performance of the measuring device according to the present invention as described in the first embodiment (in simple terms, the ability to collect scattered light reflected by the guide rail 140 and form an image on the imaging surface so as to produce a predetermined amount of blur) by simply changing the installation position of the measuring device 910 without making major changes to the internal configuration of the imaging unit 920 from the existing configuration. Therefore, the measuring device 910 according to the third embodiment achieves the objective of the present invention, which is to "measure the position and speed of an elevator car with high accuracy and high robustness against car displacement based on the imaging results of scattered light reflected by a stationary structure," while achieving the effect of reducing the design costs and mass production costs of the measuring device compared to other embodiments.

(4) Fourth Embodiment FIG. 11 is a diagram showing an example of the internal configuration of an imaging unit 1020 in a measuring apparatus 1010 according to a fourth embodiment of the present invention. The measuring apparatus 1010 according to the fourth embodiment includes an imaging unit 1020 as an imaging unit replacing the imaging unit 920 in the measuring apparatus 910 according to the third embodiment. The imaging unit 1020 is characterized by being highly robust against car displacement, since it can keep the imaging magnification of the image capture unit 1030 unchanged despite shaking of the elevator car 120 in the z-axis direction and can keep the change in the spread width of the point spread function sufficiently small against shaking in the z-axis direction. Note that the other configuration of the measuring apparatus 1010 is the same as that of the measuring apparatus 910 according to the third embodiment, and therefore detailed description thereof will be omitted.

As shown in FIG. 11, the imaging unit 1020 forms an image of the scattered light reflected by the guide rail 140 on the imaging unit 1030. Specifically, the imaging unit 1020 is composed of an objective lens 1021 (first lens), an aperture 1022, and a condenser lens 1023 (second lens). The objective lens 1021 is disposed opposite the guide rail 140 and condenses the scattered light scattered by the guide rail 140. The aperture 1022 limits the amount of scattered light condensed by the objective lens 1021. The condenser lens 1023 is disposed between the aperture 1022 and the imaging unit 1030 and condenses the scattered light whose amount has been limited by the aperture 1022, and sends the condensed scattered light toward the imaging surface of the imaging unit 1030.

Furthermore, as shown in FIG. 11 , in the measurement device 1010, the imaging unit 1020 has a telecentric optical arrangement on the object side (guide rail 140 side) to eliminate the effect of changes in magnification when the subject (detection target) guide rail 140 moves in the z-axis direction relative to the elevator car 120, and forms an image on the imaging unit 1030 using two or more lenses to suppress geometric aberrations that occur in the imaging unit 1030. Furthermore, the imaging unit 1020 may also have a telecentric optical arrangement on the image side (imaging unit 1030 side), in which case it serves to widen the dimensional tolerance in the z-axis direction (mounting tolerance in the z-axis direction) when installing the imaging unit 1030.

In other words, in the measurement device 1010, the center of the imaging surface of the imaging unit 1030, the optical axis of the condenser lens 1023, the center of the aperture 1022, and the optical axis of the objective lens 1021 are arranged so that they are located on the same straight line, and the aperture 1022 is arranged at the focal position of the objective lens 1021 on the imaging unit 1030 side, and at the focal position of the condenser lens 1023 on the objective lens 1021 side.

Furthermore, as with the third embodiment, the measurement device 1010 according to the fourth embodiment is arranged so that the guide rail 140 is located at a defocus position shifted in the optical axis direction from the conjugate plane position (focus position) of the imaging unit 1020 on the imaging unit 1030 (imaging surface). By shifting and installing the measurement device 1010 so that the guide rail 140 is at the defocus position, the spread width of the point spread function can be increased, and the spread width of the point spread function can be determined to satisfy the above-described equations 1 and 2.

In addition, in the measurement device 1010, the aperture diameter of the diaphragm 1022 is set to be sufficiently small to reduce the effect of changes in the spread width of the point spread function when the guide rail 140 is displaced in the z-axis direction relative to the elevator car 120. This allows the spread angle of the light beam to be small, making it possible to reduce changes in the point spread function 510 when the guide rail 140 is displaced in the optical axis direction from the nominal position.

As a specific condition for the aperture diameter when the aperture 1022 is set to be sufficiently small as described above, for example, the numerical aperture (N.A.) of the imaging unit 1020 may be configured to satisfy the relationship of the following equation 8.
In Equation 8, M is the optical magnification of imaging unit 1020, δz is the length of the vibration of elevator car 120 relative to guide rail 140 in the z-axis direction (vibration amplitude), and δW _PSF is the tolerance for changes in the spread width of the point spread function.

Furthermore, in the fourth embodiment, the objective lens 1021 or the condenser lens 1023 may be a cylindrical lens with a curvature in only one direction, or a toric lens with a curvature in both directions but with different curvatures, thereby imparting different optical performance to the horizontal direction (x direction) of the imaging unit 1020 and the car travel direction (y direction). By using such an asymmetric configuration, it is possible to realize an imaging unit 1020 that satisfies the conditions in each direction according to Equations 3 to 6, even if the pixels 420 and the light receiving units 430 are not square but, for example, rectangular.

The measurement device 1010 according to the fourth embodiment, configured as described above, employs a telecentric optical system, which allows the magnification of the optical system to remain unchanged even when the elevator car 120 vibrates in the z direction. Furthermore, by limiting the aperture diameter (aperture diameter) of the diaphragm 1022 to a small value, the change in the point spread function can be reduced, and the depth of field can be increased. As a result, the measurement device 1010 can achieve an optical system that is robust even when the elevator car 120 vibrates in the z direction.

(5) Fifth Embodiment FIG. 12 is a diagram showing an example of the internal configuration of an imaging unit 1120 in a measurement device 1110 according to a fifth embodiment of the present invention. While the imaging units 720, 920, and 1020 shown in the second to fourth embodiments were examples of the imaging unit 220 shown in the first embodiment, the imaging unit 1120 included in the measurement device 1110 according to the fifth embodiment does not achieve optical performance that intentionally blurs the captured image, and therefore has a different internal configuration from the imaging unit 220 shown in the first embodiment. However, when viewed as an entire measurement device, the measurement device 1110 according to the fifth embodiment is common to the measurement devices according to the first to fourth embodiments in that it achieves a characteristic configuration in which "scattered light rays incident on the light receiving unit of the imaging unit via the imaging unit are pulled back onto the surface of the guide rail 140 by back ray tracing, resulting in a scattering region that covers the entire imaging target region," and thus can be said to be an embodiment of a measurement device according to the present invention.

The imaging unit 1120 of the measuring device 1110 according to the fifth embodiment differs from the imaging unit 220 and the like shown in the first embodiment in that it includes a microlens array 1123 that focuses light rays toward the light receiving unit 1132 of the pixel (see FIG. 13). The imaging unit 1120 uses the microlens array 1123 to direct the chief ray of the group of light rays incident on each imaging point to the center of the light receiving unit 1132, thereby maintaining constant sensitivity for each position. Note that other configurations of the measuring device 1110 are the same as those of the measuring device 110 according to the first embodiment, and therefore detailed description will be omitted.

As shown in FIG. 12, the imaging unit 1120 includes a lens 1121, an aperture 1122, and a microlens array 1123, and focuses scattered light reflected by the guide rail 140 onto the light receiving unit 1132 of the imaging unit 1130. Specifically, the lens 1121 is disposed opposite the guide rail 140 and focuses the scattered light scattered by the guide rail 140. The aperture 1122 limits the amount of scattered light focused by the lens 1121 and sends it toward the microlens array 1123. The microlens array 1123 is disposed on the image plane where the lens 1121 focuses the scattered light reflected by the guide rail 140.

Figure 13 is a conceptual diagram illustrating the configuration and effects of the microlens array 1123. As shown in Figure 13, the microlens array 1123 refracts light rays that are focused by the lenses 1121 and incident on the image plane 1124 of the microlens array 1123, and emits them toward the light receiving units 1132 of the imaging unit 1130. The microlens array 1123 is configured by arranging the same number of lenses as the number of pixels in the imaging unit 1130 in an array, and the positions in the x and y directions are determined and arranged so that the optical axis of each lens passes through the center of the light receiving unit 1132.

The focal length of the microlens array 1123 and the distance from the microlens array 1123 to the imaging unit 1130 are determined so that the chief ray 1125 of the group of light rays is incident on the center of the light receiving unit 1132. Because the chief ray 1125 is a light ray that passes through the center of the aperture 1122 (see Figure 12), the brightest ray of the group of light rays that form an image on the image plane 1124 is incident on the center of the light receiving unit 1132. Note that in the imaging unit 1130, the group of light rays that form an image on the image plane 1124 are not incident on the light-shielding portion 1131 surrounding the light receiving unit 1132. Therefore, this configuration enables the light receiving unit 1132 to perform detection with maximum efficiency regardless of the incident position on the image plane 1124, and maintains constant sensitivity for each position.

As described above, in the measuring device 1110 according to the fifth embodiment, the imaging unit 1130 can be configured so that, while maintaining constant sensitivity at each position in the light-receiving unit 1132, which is narrower than a pixel, the scattering region formed when the scattered light incident on the light-receiving unit 1132 is returned to the surface of the guide rail 140 by back ray tracing covers the entire imaging target area. As a result, in cases where the stationary structure (guide rail) to be measured has a luminance pattern (reflected/scattered luminance pattern) in which the image formed by light diffusely reflected (scattered light) from the stationary structure is smaller in size than the pixels of the optical sensor, even if the elevator car 120 is displaced relative to the guide rail 140 due to vibration or the like, the measuring device 1110 according to the fifth embodiment can prevent the loss of fine feature points in the reflected/scattered luminance pattern 310 in the captured image spanning the displacement, as with the measuring device 110 according to the first embodiment, enabling pattern matching before and after the displacement by the image processing unit 240, and measuring signal information useful for controlling the operation of the elevator car 120 without sacrificing accuracy.

Note that the above-described embodiments are intended to clearly explain the present invention and do not limit the scope of the present invention. For example, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, for example, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

Furthermore, the above-mentioned components, functions, processing units, processing means, etc. may be implemented in hardware, in part or in whole, by, for example, designing them as integrated circuits. Furthermore, the above-mentioned components, functions, etc. (e.g., image processing unit 240, etc.) may be implemented in software by a processor interpreting and executing a program that implements each function. Information such as the programs, tables, and files that implement each function can be stored in memory, a storage device such as a hard disk or SSD (Solid State Drive), or a storage medium such as an IC card, SD card, or DVD. In particular, a program may be installed on a device such as a computer from a program source. The program source may be, for example, a program distribution server or a non-transitory storage medium readable by a computer. When the program source is a program distribution server, the program distribution server includes a processor (e.g., a CPU) and non-transitory storage resources, and the storage resources may further store the distribution program and the program to be distributed. Then, by the processor of the program distribution server executing the distribution program, the processor of the program distribution server may distribute the program to be distributed to other computers. Also, in the following description, two or more programs may be realized as one program, or one program may be realized as two or more programs.

In addition, the control lines and information lines shown in the drawings are those considered necessary for explanation, and do not necessarily show all control lines and information lines on the product. In reality, it can be assumed that almost all components are interconnected.

10 Elevator system 110 Measuring device 120 Elevator car 130 Elevator control unit 140 Guide rail 210 Optical transmitting unit 220 Imaging unit 230 Imaging unit 240 Image processing unit 310 Reflected/scattered luminance pattern 410 Image 420 Pixel 430 Light receiving unit 510 Point spread function 520 Inverse image 610 Output 710, 910, 1010, 1110 Measuring device 720, 920, 1020, 1120 Imaging unit 721, 921, 1021, 1121 Objective lens (lens)
722, 922 Aperture 723, 1023 Condenser lens 724 Phase plate 730, 930, 1030, 1130 Imaging unit 810 Annular groove 820, 821, 822, 823 Light ray 830 Focus 831, 832 Position 840 Optical axis 1123 Microlens array 1124 Image plane 1125 Chief ray 1131 Light blocking unit 1132 Light receiving unit

Claims (11)

A measuring device that is installed on an elevator car moving in a hoistway and measures at least one of a moving distance or a speed of the elevator car,
an optical transmitter that transmits light to illuminate a stationary structure disposed along the direction of movement of the elevator car in the elevator shaft;
an imaging unit that collects scattered light from the stationary structure by passing the scattered light from the light onto an imaging plane by a collecting lens;
an imaging unit that captures optical signals of the scattered light that are focused on the light receiving portions of a plurality of pixels that constitute the imaging surface, converts the signals into electrical signals, and captures an image;
an image processing unit that calculates and transmits at least one of a moving distance or a speed of the elevator car based on the electrical signal converted by the imaging unit;
Equipped with
the imaging unit is configured so that no gaps are generated between pixels with different scattering regions when the scattered light incident on the light receiving unit of each pixel on the imaging surface is returned onto the stationary structure. The measuring device according to claim 1 , wherein the imaging unit blurs the scattered light from the stationary structure and focuses the light on the imaging surface. The measurement device according to claim 2, wherein the imaging unit focuses scattered light from the stationary structure onto the imaging surface by blurring the scattered light at least in the vibration direction of minute vibrations that may occur in the elevator car. When the full width of the point spread function in the imaging unit determined by the RMS (Root Mean Square) method is W _PSF , the pitch of the pixels on the imaging surface is W _PIX , and the width of the light receiving portion of the pixel on the imaging surface is W _PD ,
The measuring device according to claim 2, wherein: The imaging unit
a diaphragm for limiting the amount of scattered light collected by the collecting lens;
The measurement device according to claim 2 , further comprising an optical component having a plurality of grooves formed therein, the grooves applying a predetermined aberration to light rays passing through the diaphragm. The measuring device according to claim 5, wherein the maximum amount of aberration in the optical axis direction imparted by the optical component is greater than the amplitude of vibration of the elevator car. The measuring device according to claim 2 , wherein the imaging unit is configured by an optical system that is telecentric at least on the side of the stationary structure. The measurement device according to claim 2 , wherein the imaging surface of the imaging unit is arranged at a position different from a focal position optically conjugate with the stationary structure by the imaging unit. the imaging unit has a diaphragm that limits the amount of scattered light collected by the collecting lens,
3. The measurement device according to claim 2, wherein the aperture diameter of the diaphragm is limited based on the optical magnification of the focusing lens, the amplitude of vibration of the elevator car, and changes in the spread width of a point spread function due to the scattered light focused on the imaging surface. the imaging unit includes a microlens array between the condenser lens and the imaging surface;
The measurement device according to claim 1 , wherein the microlens array focuses a group of rays of light scattered from the stationary structure and passing through the focusing lens onto the imaging surface. An elevator car moving through a shaft,
a guide rail disposed in the elevator shaft along a moving direction of the elevator car;
an elevator control unit that controls the operation of the elevator car;
a measuring device installed on the elevator car to measure at least one of the moving distance and the speed of the elevator car;
Equipped with
The measuring device is
an optical transmitter that transmits light to irradiate the guide rail;
an imaging unit that collects scattered light from the guide rail on an imaging surface by passing the scattered light through a collecting lens;
an imaging unit that captures optical signals of the scattered light that are focused on the light receiving portions of a plurality of pixels that constitute the imaging surface, converts the signals into electrical signals, and captures an image;
an image processing unit that calculates and transmits at least one of a moving distance or a speed of the elevator car based on the electrical signal converted by the imaging unit;
and
an imaging unit configured to prevent gaps from occurring between pixels with different scattering regions when the scattered light incident on the light receiving unit of each pixel on the imaging surface is returned onto the guide rail.