KR102090006B1 - Illumination system - Google Patents

Abstract

The illumination system includes a measurement stage, an irradiation unit, a light receiving unit, and a processing unit. The irradiation unit irradiates incident light with respect to the measurement object located on the measurement stage, and includes a plurality of light sources arranged in a dome shape. The light-receiving unit acquires reflected lights. The processing unit controls the light sources to be lit according to the domed sinusoidal pattern. The processing unit controls the light sources to be sequentially turned on by shifting N times according to a dome-shaped sine wave pattern with respect to a specific measurement position of the measurement object, and from the intensity of the N reflection lights, the phase at the specific measurement position of the measurement object, the N reflection lights The average of the intensity of the field and the visibility of the N reflected lights are calculated. Accordingly, the material to be measured can be easily determined.

Description

Lighting system {ILLUMINATION SYSTEM}

The present invention relates to a lighting system, and more particularly, to a lighting system enabling material determination of an object.

In general, various methods of recognizing a material for an arbitrary object have been studied.

These methods generally adopt a method of recognizing the material of the object through the internal structure of the object, such as a method of grasping the incident wave on the object and measuring the reflected wave returning to the material of the object.

However, since this method needs to grasp the internal structure of the object, this method complicates the system for material determination and greatly increases its manufacturing cost, and the material determination method is not only difficult, but also for material determination for various objects. There are limitations, and there is a problem that reliability cannot be secured.

Therefore, development of a material recognition lighting system and a material recognition method capable of easily and accurately recognizing an object's material at low cost is required.

Therefore, the problem to be solved by the present invention is to provide a lighting system suitable for easily and accurately recognizing the material of an object at low cost.

An illumination system according to an exemplary embodiment of the present invention includes a measurement stage, an irradiation unit, a light receiving unit, and a processing unit. The measurement object is located on the measurement stage. The irradiation unit includes a plurality of light sources for irradiating incident light with respect to the measurement object, respectively, and the plurality of light sources are arranged to surround an upper portion of the measurement object in a dome shape, so that incident light from multiple directions to the measurement object They can be selectively irradiated toward the measurement object. The light receiving unit acquires reflected light by the measurement object according to the incident lights irradiated by the irradiation unit. The processing unit controls the light sources to be lit according to a dome-shaped sine wave pattern. The processing unit controls the light sources to be sequentially turned on by shifting the light sources N times according to the dome-shaped sine wave pattern for a specific measurement position of the measurement object (N is a natural number of 2 or more), and the irradiation unit is sequentially lit N pattern lights are generated and irradiated to the measurement object, and the light receiving unit receives N reflected lights of N pattern lights irradiated to the measurement object. The processing unit calculates a phase at a specific measurement position of the measurement object, an average of the intensity of the N reflected lights, and the visibility of the N reflected lights from the intensity of the N reflected lights.

In one embodiment, the processing unit may generate image data for the measurement region based on the calculated phase, the average, and the visibility.

In one embodiment, the processing unit may determine the material of the measurement object from the calculated phase, the average, and the visibility.

In one embodiment, the light sources of the irradiation unit may each include a light emitting diode (LED).

In one embodiment, the irradiation unit is disposed above the measurement object to cover the surroundings of the measurement object, and may further include an illumination cover in which the light emitting diodes are installed.

In one embodiment, the lighting cover may have a shape including at least a portion of the dome, and the light emitting diodes are provided in a ring shape having different diameters when viewed from below, such that at least a portion of the dome It may be formed of a number of rows (row) in the shape of the containing.

In one embodiment, the illumination cover, may have an opening formed corresponding to the upper portion of the measurement object, the light receiving unit, may be arranged to receive the reflected light reflected from the measurement object through the opening.

In one embodiment, the irradiation unit, the first irradiation unit for providing incident light from the light emitting diodes mounted on the lighting cover to the measurement object and the opening through the opening formed in the lighting cover to provide the incident light to the measurement object 2 may include an irradiation unit.

In one embodiment, the plurality of light sources may be arranged at (r, θ, φ) coordinates on a spherical coordinate system centering on the measurement position of the measurement object.

For example, in the dome-shaped sine wave pattern, the r-coordinate is constant, and a sine wave may be formed on a hemisphere as the θ-coordinate changes from 0 to 360 degrees in a specific φ-coordinate within a range of 0 to 90 degrees. .

For example, in the dome-shaped sine wave pattern, the r-coordinate is constant, and a sine wave may be formed on a hemisphere as the φ-coordinate in a specific θ-coordinate within a range of 0 to 360 degrees changes from 0 to 90 degrees. .

For example, in the dome-shaped sine wave pattern, the r-coordinate is constant, and a sine wave may be formed on a hemisphere as the θ-coordinate changes from 0 to 180 degrees in a specific φ-coordinate within a range of -90 to 90 degrees. have.

According to the present invention, by irradiating incident light from multiple directions to a measurement object using a plurality of light sources, and controlling the light sources to light according to a dome-shaped sine wave pattern formed on the dome, at a specific measurement position of the measurement object By calculating the phase, the average of the intensity of the reflected light and the visibility of the reflected light, the material of the measurement object can be easily determined.

In addition, unlike the conventional planar sinusoidal pattern, the domed sinusoidal pattern can be formed on a dome-shaped hemisphere, so the phase, the average and the visibility are very accurate at any measurement position. Rather, since the absolute measurement value at each measurement position is very accurate, the relationship between each of the measurement positions can also have a very accurate value.

Therefore, when the phase, the average, and the visibility, which are calculated as described above, are represented or processed as an image for material determination, the user can easily utilize them for material determination.

In addition, even if the intensity distribution of the reflected light is not directly obtained for material determination, the material determination may be possible based only on the information of the phase, the average, and the visibility.

In addition, the lighting system, in addition to the material determination as described above, may also be used to determine the state of the surface, it can also be utilized for defect determination.

In addition, the phase, the average, and the invisibility calculated as described above, when the criteria for various material determination, the criteria for determining the condition of the surface, the criteria for determining the defect, etc. are set as reference data in advance, the material is directly processed by the processing unit Since it is possible to perform the determination, the status determination, and the failure determination, it is possible to improve the user's convenience and reliability.

1 is a conceptual diagram showing a lighting system according to an embodiment of the present invention.
FIG. 2 is a conceptual diagram for explaining the operation of the lighting system of FIG. 1.
FIG. 3 is a plan view of the lighting system of FIG. 1 observed from the bottom.
4 is a conceptual diagram illustrating a first embodiment of a dome-shaped sine wave pattern of the lighting system shown in FIG. 1.
5 is a conceptual diagram showing a second embodiment of the dome-shaped sine wave pattern of the lighting system shown in FIG. 1.
6 is a conceptual diagram illustrating a third embodiment of the dome-shaped sine wave pattern of the lighting system shown in FIG. 1.
7 is a graph for explaining a method of determining the material of a measurement object according to an embodiment of the present invention.

The present invention can be applied to various changes and may have various forms, and specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosure form, and it should be understood that all modifications, equivalents, and substitutes included in the spirit and scope of the present invention are included. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. For example, the first component may be referred to as a second component without departing from the scope of the present invention, and similarly, the second component may also be referred to as a first component.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “include” or “have” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, or that one or more other features or It should be understood that the existence or addition possibilities of numbers, steps, actions, components, parts or combinations thereof are not excluded in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains.

Terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application. Does not.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

1 is a conceptual diagram showing a lighting system according to an embodiment of the present invention, Figure 2 is a conceptual diagram for explaining the operation of the lighting system of FIG.

1 and 2, the lighting system 100 according to an embodiment of the present invention includes a measurement stage 110, an irradiation unit 120, a light receiving unit 130, and a processing unit 140.

In the measurement stage 110, a measurement object MT is located. The measurement stage 110 may be opened upward. In FIG. 1, although the measurement stage 110 is fixed, the position, posture, and the like of the measurement object MT may be controlled by a processing unit 140 to be described later or a control unit provided from the outside.

The irradiation unit 120 includes a plurality of light sources LS irradiating incident light IL to the measurement object MT, respectively. The plurality of light sources LS of the irradiation unit 120 are arranged to surround the upper part of the measurement object MT in a dome shape, so that incident light IL from multiple directions to the measurement object MT ) Allows selective irradiation toward the measurement object MT. Meanwhile, the light sources LS may be serially connected to each other, and lighting control may be individually possible.

The incident direction of the incident light IL may be represented by an incident angle θ inclined with respect to a normal direction to the measurement object MT. For example, the incident lights IL may be incident in all upward directions, and the incident lights IL may represent an incident direction with an incidence angle θ between 0 ° and 90 ° inclination angle.

For example, the light sources LS of the irradiation unit 120 may each include a light emitting diode (LED). Alternatively, the light sources LS of the irradiation unit 120 may include other types of light emitting units.

In one embodiment, the irradiation unit 120 may further include an illumination cover (CV). The illumination cover CV is disposed on the measurement object MT, covers the periphery of the measurement object MT, and the light emitting diodes are installed.

For example, the light emitting diodes may include at least one of red, green, and blue light emitting diodes, and may be a white light emitting diode. In addition, the light-emitting diodes may be provided with light-emitting diodes of different colors alternately installed in the lighting cover CV, or light-emitting diodes having their own color changed. Further, the light emitting diodes may have a fixed brightness or may have a variable brightness.

3 is a plan view of the lighting system of FIG. 1 observed from the bottom.

Referring to FIG. 3, in one embodiment, the light emitting diodes may be formed in a strip type physically and electrically connected to each other. That is, the strip-type light-emitting diodes may be connected to each other in a strip, as shown in FIG. 3. Meanwhile, the number of light emitting diodes illustrated in FIG. 3 is set as an example, and may be more or less than this. The same applies to the case of FIGS. 4 to 12 described later.

For example, the illumination cover CV may have a shape including at least a portion of a dome, and the strip-type light emitting diodes may have different diameters when viewed from below, as shown in FIG. 3. It may be provided in a ring shape having a plurality of rows (R1, R2, ..., Rn-1, Rn) inside the shape including at least a portion of the dome. That is, the strip-type light-emitting diodes, a plurality of rings having different diameters can be arranged in sequence to form a row.

The plurality of light emitting diodes arranged as described above may be connected in series. However, in this case, when controlling the lighting of the light-emitting diodes, a time delay may occur and may not be controlled as desired, so the light-emitting diodes may be grouped into a predetermined number of groups.

For example, a plurality of light emitting diodes installed in the lighting cover CV may adjust a connection state according to the number and / or arrangement of light emitting diodes. That is, the plurality of light emitting diodes may be grouped into a plurality of channels based on a predetermined number, or may be grouped into a plurality of channels based on the arranged column, and both the number and the arranged column are considered. It can also be grouped into a plurality of channels.

For example, the light emitting diodes forming each ring are connected to each other in the same column, and in the case of a column close to the opening OP described later (for example, R1), the number of light emitting diodes is formed so that the opening ( For the columns close to OP), light-emitting diodes of different columns (for example, R1 and R2) can also be connected to group the same or similar number for each channel. In this case, if necessary, it is also possible not to connect to each other even in the same row. In the processing unit 140 to be described later, the light-emitting diodes divided into a plurality of channels may be divided for each channel to independently control lighting.

Meanwhile, in order to dissipate heat generated by the light emitting diodes, the lighting cover CV may be formed of metallic, for example, aluminum. In addition, by attaching the connection line between the light emitting diodes and the lighting cover (CV) using an electric heat bond or a thermal bond, the light emitting diodes are firmly installed on the lighting cover (CV) while simultaneously radiating heat. You can make this possible.

In one embodiment, the lighting cover CV may have an opening OP formed corresponding to an upper portion of the measurement object MT. The opening OP may be used as an open passage to receive the reflected light RL from the light receiving unit 130 to be described later. In addition, the opening OP may be used as a path for irradiating incident light toward the measurement object MT in the additional illumination (second irradiation unit) described later.

In one embodiment, the irradiator 120 may include a first irradiator 122 and a second irradiator 124.

The first irradiation unit 122 provides incident light IL1 to the measurement object MT from the light emitting diodes mounted on the illumination cover CV.

The second irradiator 124 provides incident light IL2 to the measurement object MT through the opening OP formed in the illumination cover CV.

As shown in FIG. 1, both the first irradiator 122 and the second irradiator 124 provide light generated from the light sources LS described above as the measurement object MT, and the first irradiator 122 is mounted on the lighting cover (CV), the second irradiation unit 124 may be mounted on a separate plate (PL) as an example.

In one embodiment, the lighting system 100 may further include a beam splitter 150.

For example, as illustrated in FIGS. 1 and 2, the second irradiator 124 may be disposed on the opening OP, and the light receiving unit 130 may be on one side of the opening OP. Can be deployed.

In this case, the beam splitter 150 transmits the incident light IL2 generated from the second irradiator 124 to the measurement object MT, and the reflected light RL by the measurement object MT Reflect the light to the light receiving unit 130.

Accordingly, the reflected light reflected in the same optical axis direction as the optical axis of the second irradiation unit 124 can be effectively received by the light receiving unit 130.

Meanwhile, unlike the arrangements illustrated in FIGS. 1 and 2, the second irradiation unit 124 may be disposed on one side of the opening OP, and the light receiving unit 130 may be disposed on the upper portion of the opening OP. It may be deployed.

Since the incident light IL2 provided from the second irradiation unit 124 passes through the above-described beam separation unit 150, the amount of light compared to the incident light IL1 provided from the first irradiation unit 122 Loss may occur. In addition, since the light sources of the second irradiation unit 124 are located farther from the measurement object MT than the light sources of the first irradiation unit 122, the amount of light reaching the measurement object MT is the second The irradiation unit 124 may be less than the first irradiation unit 122. Therefore, for example, the arrangement density of the light sources of the second irradiator 124 may be greater than the arrangement density of the light sources of the first irradiator, thereby compensating for the amount of light lost.

In one embodiment, the irradiation unit 120 may include a diffuser (diffuser) (DF).

The diffuser DF is disposed in front of the light sources LS and diffuses light generated from the light sources LS. In addition, the diffuser (diffuser) (DF) has a shape corresponding to the lighting cover (CV). Accordingly, the diffuser DF may have an opening OPD in the same manner as the opening OP of the lighting cover CV.

The diffuser DF may be disposed in front of the light sources LS of the first irradiation unit 122 and in front of the light sources LS of the second irradiation unit 124, respectively.

The light receiving unit 130 acquires reflected light RL by the measurement object MT according to the incident lights irradiated by the irradiation unit 120.

As described above, the light receiving unit 130 may be arranged to receive reflected light RL reflected from the measurement object MT through the opening OP, and through the beam separation unit 150 The reflected light RL can be received.

The light receiving unit 130 may be installed to adjust the light receiving angle in order to analyze various signal patterns according to a desired method. In addition, the light receiving unit 130, considering the installation error of the beam separation unit 150, the processing error of the opening (OPD) formed in the diffuser (DF), and the diversity of the size or resolution of the light receiving unit 130 itself, It can have installation tolerance.

In one embodiment, the light receiving unit 130 may include an optical sensor capable of measuring the intensity (intensity) of the reflected light (RL), the incident light is reflected by the measurement object (MT), CCD or CMOS camera It may include a camera such as. In addition, the light receiving unit 130 may include a lens disposed in front of the optical sensor or the camera.

The processing unit 140 controls the light sources LS to be lit according to a dome-shaped sine wave pattern, and generates image data from the reflected light RL acquired by the light receiving unit 130.

In this specification, the dome-shaped sine wave pattern is defined as a sine wave pattern formed on a curved surface formed by the dome. The dome-shaped sine wave pattern is formed in a curved shape, unlike a sine wave pattern mainly used in the field of optical measurement and inspection, which is formed in a planar shape. The conventional sine wave pattern has a lattice pattern in which the sine wave extends and extends as it is in the y-axis while forming a sine wave in the x-axis when observed on a planar rectangular coordinate system. On the other hand, the domed sinusoidal pattern may be referred to as a concept in which the above-described grid pattern is applied along a domed curved surface (eg, a hemispherical surface). Specific examples of the domed sinusoidal pattern will be described later.

The processing unit 140 may control the light sources LS in a serial communication method. The processing unit 140 may perform input and control of a user through a control device, such as a computer, provided externally.

As described above, the light sources LS may be formed of a plurality of channels connected to each other in series, and the processing unit 140 may control lighting of the light sources LS for each channel connected in series with each other. have. That is, since the connection structures for transmitting data are serially formed, the light sources LS may be individually controlled by the light sources LS by a serial communication method.

The light sources LS, for example, a plurality of light emitting diodes, can be divided into and controlled by a plurality of sections for partial or area control when using a parallel communication method, but to implement more various types of free lighting In order to set the size of the sections small, the number of sections must be connected to the control device, and thus a plurality of wirings are required. In order to adjust the brightness of each section, rapid control with a relatively high current is required. The structure of the lighting device and its control device can be complicated and the manufacturing cost can be increased, and since the degree of freedom of control is low in terms of control for each section, it may be difficult to implement various types of lighting.

However, in the case of following the serial communication method, such as the irradiation unit 120, since the light sources LS can be individually controlled by having a serially formed connection structure for data transmission, lighting can be freely implemented. In order to implement such a serial communication method, a pulse width modulation (PWM) that may include a circuit that enables serial communication such as a latch, and which can control the brightness of the light sources LS, It may include a control circuit such as a DA converter.

Meanwhile, as described above, when a plurality of light sources LS are all connected in series, lighting and brightness of each light source LS may need to be collectively controlled, and accordingly, time delay may occur. The light sources LS may be grouped into a predetermined number of groups or channels, and each channel may be controlled in parallel to prevent time delay.

Since the irradiator 120 has a structure capable of irradiating light in almost all directions based on the measurement object MT, the processing unit 140 is the light source LS according to various types of domed sinusoidal patterns Can be controlled so that they light up.

For example, the domed sine wave pattern may have various wavelengths and amplitudes on a curved surface formed by the dome, and may include a pattern in which at least two domed sinusoidal patterns are synthesized. In addition, the dome-shaped sine wave pattern may be controlled in intensity and lighting in various ways according to the arrangement positions of a plurality of light sources arranged in the dome shape.

FIG. 4 is a conceptual diagram showing a first embodiment of a dome type sine wave pattern of the lighting system shown in FIG. 1, and FIG. 5 is a conceptual diagram showing a second embodiment of a dome type sine wave pattern of the lighting system shown in FIG. 1.

4 and 5, it is assumed that the plurality of light sources LS are arranged on a spherical coordinate system centered on the measurement position of the measurement object (one for convenience in FIGS. 4 and 5). ), And the light sources LS can express coordinates with (r, θ, φ). At this time, when the dome shape is a hemispherical shape, the r-coordinates of the light sources LS are all the same. In addition, in the spherical coordinate system, a plane in which the measurement stage 110 is present corresponds to a surface of φ = 0, and a dome-shaped region in which the light sources LS are present is generally θ = 0 to 360 degrees, φ = 0. It is ~ 90 degrees (or θ = 0 to 180 degrees, φ = 0 to 180 degrees).

In the first embodiment, in the dome-shaped sine wave pattern, r-coordinates are constant, and θ-coordinates change from 0 to 360 degrees (or -180 to 180 degrees) in a specific φ-coordinate within a range of 0 to 90 degrees Accordingly, a sine wave can be formed on the hemisphere. That is, as shown in FIG. 4, the dome-shaped sine wave pattern may be formed such that the sine wave valley is positioned at the position indicated by the dotted line. In this case, the dome-shaped sine wave pattern may form a pattern of watermelon stripes observed from above. Alternatively, in the second embodiment, in the dome-shaped sine wave pattern, the r-coordinate is constant, and the φ-coordinate in a specific θ-coordinate within a range of 0 to 360 degrees changes from 0 to 90 degrees to cause a sine wave on the hemispherical surface. It can also form. That is, as shown in FIG. 5, the dome-shaped sine wave pattern may be formed such that the sine wave valley is positioned at the position indicated by the dotted line. In this case, the dome-shaped sine wave pattern may form a ring-shaped pattern of different radii when viewed from the top. On the other hand, in the intensity graph of Fig. 5, for convenience, phi-coordinates are expressed in reverse.

6 is a conceptual diagram illustrating a third embodiment of the dome-shaped sine wave pattern of the lighting system shown in FIG. 1.

Referring to FIG. 6, unlike the spherical coordinate system of FIGS. 4 and 5, a plane in which the measurement stage 110 is present corresponds to a surface of θ = 0, and a dome-shaped region in which the light sources LS are present Is generally θ = 0 to 180 degrees, and φ = -90 to 90 degrees.

In the third embodiment, the dome-shaped sine wave pattern has a constant r-coordinate and forms a sine wave on a hemisphere as the θ-coordinate in a specific φ-coordinate within a range of -90 to 90 degrees changes from 0 to 180 degrees. You can. That is, as shown in FIG. 6, the dome-shaped sine wave pattern may be formed such that the sine wave valley is positioned at the position indicated by the dotted line (the dotted line on the hemisphere corresponds to the alternately located floor and valley). In this case, the dome-shaped sine wave pattern may form a watermelon stripe pattern observed from the side. On the other hand, in the intensity graph of Fig. 6, θ-coordinates are expressed in reverse for convenience.

The processing unit 140 may generate data necessary for material determination from reflected light RL by incident light IL of a dome-shaped sine wave pattern generated by various methods as described above. At this time, the processing unit 140 may acquire data required for the material determination by the following method for incident light according to the dome-shaped sine wave pattern.

First, the processing unit 140 controls the light sources to be sequentially turned on by shifting the light sources N times according to a sine wave pattern for a specific measurement position of the measurement object MT (N is a natural number of 2 or more), and the irradiation unit 120 ) Generates the N pattern lights that are sequentially lit, and irradiates the measurement object MT, and the light receiving unit 130 receives N reflected lights of the N pattern lights that are irradiated to the measurement object MT. .

Subsequently, the processing unit 140, from the intensity of the N reflected lights RL, a phase at a specific measurement position of the measurement object MT, an average of the intensity of the N reflected lights RL, and the N Visibility of the reflected light RL may be calculated.

For example, the phase, the average, and the visibility can be calculated by applying the following method.

Phase

N-shift is applied to the sine wave pattern, and the intensity of the reflected lights RL by the incident light IL is obtained from the information, thereby obtaining a phase at a specific measurement position of the measurement object MT. You can.

For example, in the case of applying a 4-bucket algorithm that applies N = 4 shifts, the phase can be obtained as follows.

First, the intensity (I) of the reflected light RL received from the light receiving unit 130 by irradiating a sine wave to the measurement object MT is expressed by a dominant equation of a moire interference pattern as shown in Equation 1 below. do.

In this equation, I _P is the intensity of the reflected light (RL), I ₀ (x, y) is the average intensity, γ is the visibility (visibility), φ (x, y) is the initial phase to be measured, Δ is the phase shift amount Means Further, (x, y) represents a specific measurement position of the measurement object MT, and may be differently expressed according to a coordinate system indicating the specific measurement position.

In Equation 1, since the intensity of the reflected light RL is a function of the initial phase φ, the intensity of the reflected light RL can be measured to obtain the initial phase φ.

Specifically, by substituting 0, π / 2, π, and 3π / 2 radians for the phase shift amount Δ of Equation 1, respectively, to obtain I ₁ , I ₂ , I ₃ , I ₄ , the following Equations 2 to It is expressed as 5.

From Equations 2 to 5, Equation 6 below can be obtained.

If Equation 6 is rewritten, Equation 7 below can be obtained.

The obtained initial phase φ will be referred to as a phase, and the phase may represent a slope at a specific position (x, y) of the surface of the measurement object MT. At this time, the method of obtaining the phase is similar to the conventional deflectometry (deflectometry) method, but the sine wave pattern formed in the conventional planar shape is irradiated from the plane, so that the phase does not represent the slope, whereas the domed sine wave of the present invention Since the pattern is irradiated on the curved surface, the phase can represent the slope.

When the light receiving unit 130 is positioned vertically upward as shown in FIG. 1, a surface inclined at a specific position of the measurement object MT should be within at least approximately -45 ° to 45 °, so that the light receiving unit 130 Since the measurement is possible, the measurable tilt range is approximately -45 ° to 45 °. At this time, the geometry between the position of the measurement stage 110, the position of the surface of the measurement object MT spaced apart from the measurement stage 110, the lights disposed at the bottom of the lights LS, etc. Depending on the placement relationship, the tilt range may vary somewhat, but it is negligible or simply correctable.

Average

For example, in the case of applying a four-bucket algorithm that applies N = 4 shifts, the average can be calculated as follows.

Equation 8 can be obtained simply by arithmetic average of I ₁ to I ₄ obtained in Equations 2 to 5.

In this equation, A (x, y) means the average of four intensity data measured at a specific measurement position (x, y) of the measurement object MT.

Visibility

The visibility refers to the ratio of the amplitude B (x, y) to the average A (x, y).

For example, in the case of applying a 4-bucket algorithm that applies N = 4 shifts, the visibility can be obtained as follows.

In this equation, V (x, y) is the visibility of four intensity data measured at a specific measurement position (x, y) of the measurement object MT, and B (x, y) and A (x, y) Denotes the amplitude and average of each of the four intensity data.

As described above, the method of obtaining the phase, average, and visibility is similar to that of the conventional diflectometry method, but in the case of the conventional diplexometry method, the state of the surface of the measurement object, that is, the slope of the surface of the measurement object, of the surface It has been used only for grasping shape, surface scratches, etc., and has not been used for material determination as in the present invention. This is because a conventional lighting device has implemented a sine wave pattern light formed in a planar shape by using a display device such as an LCD monitor or a grid transfer device that does not completely or adequately cover the upper portion and covers a very limited range flatly. . As described above, according to the conventional deflexometry method of irradiating a planar sine wave pattern light in a limited range, a specific position where the camera is disposed only for light irradiated at a specific angle to a measurement object at a specific position where the pattern light source is disposed The reflected light reflected at a specific angle with respect to the measurement object is received. Therefore, it is possible to measure the height of the point by measuring the phase of the point with the image measured at one measurement position, but the difference in brightness between the images measured at multiple measurement positions may occur, so The relative relationship between locations is not accurate.

However, in the irradiation unit 120 of the present embodiment, the plurality of light sources LS are arranged to surround the upper part of the measurement object MT in the form of a dome, and are individually connected in series with each other. Since lighting control may be possible, incident light ILs from a much wider range of directions to the measurement object MT (almost upward in all directions) move the sine wave pattern toward the measurement object MT at the same distance (hemisphere) Radius) and receiving light from the light receiving unit 130 located at the same distance, the intensity of the absolute reflected light at a specific measurement position can be obtained very accurately, and since the relative relationship between multiple measurement positions is very accurate, measurement The reflectance for each measurement position, which requires a relative relationship for each position, can be measured very accurately.

7 is a graph for explaining a method of determining the material of a measurement object according to an embodiment of the present invention. The graph of FIG. 7 shows the intensity distribution of reflected light of an object having an arbitrary material, and shows an example of the case where light is irradiated from above vertically.

Referring to FIG. 7, when an intensity distribution for each direction of the reflected lights is measured for an object having an arbitrary material, the intensity distribution for each direction of the reflected lights is the first intensity distribution (ID1) and diffusion of specular reflected light. ) It can be represented by the second intensity distribution (ID2) of the reflected light.

At this time, the reflection angle RA of the first intensity distribution ID1 is a parameter indicating the angle at which the axis of symmetry of the first intensity distribution ID1 is inclined relative to the vertical upward direction, which corresponds to the phase obtained by the measurement.

In addition, the total area (AR = AR1 + AR2) of the first intensity distribution ID1 and the second intensity distribution ID2 is the total of the first intensity distribution ID1 and the second intensity distribution ID2. A parameter representing an area, which corresponds to the average of the intensity of the reflected lights RL obtained by the measurement as the total reflectance.

In addition, the spread angle FA of the first intensity distribution ID1 is a parameter representing the width of the elongated tap shape (see FIG. 2), which is the degree of roughness or glitter, and the measurement object MT obtained by the measurement. Corresponds to its visibility.

Since the parameters have different tendencies depending on the material of the object, it is possible to determine the material of the measurement object MT based on at least one of the parameters.

For example, the total reflectance of the measurement object MT obtained from the entire area of the first intensity distribution ID1 and the second intensity distribution ID2 is approximately 40% or more, and the second intensity distribution ID2 If the area AR2 is very small and the diffuse reflectance of the measurement object MT is below a reference value, the measurement object MT may be determined as a metal material.

As another example, the diffusive reflectance of the measurement object MT obtained from the area AR2 of the second intensity distribution ID2 is approximately 40% or more, and the first intensity indicating the degree of twinkling of the measurement object MT The spread angle FA of the distribution ID1 is approximately 40 ° or more, and the total reflectance of the measurement object MT obtained from the total area of the first intensity distribution ID1 and the second intensity distribution ID2 is When it is approximately 50% or more, the measurement object MT may be determined by a paper material.

For the material determination as described above, after obtaining the reference data in advance through experiments on various materials, it is possible to determine the material by measuring the desired measurement object for actual material determination and comparing it with the reference data.

In the present invention, since the phase, average, and visibility of the measurement object MT obtained above correspond to each parameter as described above, when obtaining the phase, average, and visibility, the first intensity distribution Material determination may be possible without directly obtaining (ID1) and the second intensity distribution (ID2).

In one embodiment, the processing unit 140 utilizes phase, average, and visibility acquired for each measurement position in a predetermined measurement area of the measurement object MT, as image data having optical meaning for the measurement area. Can generate The generated image data may be used as a tool for a user to directly determine the material by observing it.

First, the phase is information representing a slope of the surface of the measurement object MT, and a slope image in which grayscales of pixels are measured for each measurement object MT may be provided. That is, a phase that can be measured in each pixel is represented by a minimum of 0 and a maximum of 255 to generate a gradient image having a range of 0 to 255 for the measurement region. For example, if the minimum and maximum slopes are -45 ° and 45 °, respectively, -45 ° can be represented as 0 and 45 ° as 255, respectively, and the gray scale on a horizontally formed surface with a slope of 0 is 127. . On the other hand, the coordinates for any position on the surface of the measurement object MT can be represented by a rectangular coordinate system or a polar coordinate system, and each coordinate component (x, y of the rectangular coordinate system or r, θ of the polar coordinate system) according to the coordinate system It can be obtained, and it can be expressed as an image for each coordinate component or as an image by combining coordinate components.

Next, the average is information representing the reflectance characteristics of the measurement object MT, and a reflectance image in which a pixel-specific reflectance of the measurement object MT is expressed in grayscale may be provided. Since these images are averaged images of various reflected light according to the movement of the pattern, they correspond to images photographed under illumination that uniformly irradiates light from all directions in the upper direction, indicating reflectances representing average brightness for various surface conditions. You can. That is, a reflectance image having a range of 0 to 255 for a measurement area may be generated by representing an average measured at each pixel with a minimum of 0 and a maximum of 255.

In addition, the visibility is information indicating the twinkling or roughness characteristics of the measurement object MT, and the glittering or roughness of each pixel of the measurement object MT is expressed in grayscale using the visibility. Alternatively, a roughness image may be provided. Visibility indicates the degree of change in the brightness reflected with respect to the irradiated sine wave pattern, so as the shiny surface reflects the formed pattern as it becomes, the visibility of the surface of the measurement object MT is largely invisible. It has a value proportional to, and the roughness of the surface of the measurement object MT is generally inversely proportional to the visibility. Accordingly, the glitter image or the roughness image may be generated to have a range of 0 to 255 for the measurement area by indicating the invisibility or inverse number measured at each pixel as a minimum of 0 and a maximum of 255.

Therefore, the processing unit 140 is based on the phase, average, and visibility obtained for each measurement position in a predetermined measurement area of the measurement object MT, and the slope image and average of the measurement area of the measurement object MT, respectively. Images, glitter (or roughness) images, and processed or combined images (hereinafter referred to as “slope images, etc.”) can be generated.

The user can directly determine the material using the tilt image generated as described above. Material determination may be made by using the gradient image of the type of material, such as whether the surface of the object MT is metal or dielectric, for example, the object MT is copper, SUS, In the case of any one of aluminum and silver, when the brightness shown in the reflectance image is very bright and displayed in a grayscale of 250, it can be determined as silver, and when displayed in a grayscale of 128, it can be determined as copper. .

In addition, further from the material determination, the state of the surface of the object to be measured MT can also be determined. The slope image is used to determine which of the scratches, marks, and processing patterns are formed on the surface of the object to be measured MT. Can grasp.

On the other hand, the tilt image, etc., the material or surface state of the object to be measured (MT) may appear in different aspects depending on the color of the illumination, so the color of the pattern illumination irradiated to obtain the tilt image, etc., is various other than white You can also use color.

For example, for green pattern lighting, the reflectivity is about 50% (grayscale about 127), the twinkle is about 90% or higher (grayscale about 230 or higher), and the slope is the distribution of the slope of the spherical surface across the image. If it has, it can recognize both the state and material of the surface, such as a concave polished copper.

On the other hand, in addition to determining the state and material of the surface, it is also possible to generate a necessary processed image by exaggerating the phase, average, visibility, or image related thereto for the determination of defects.

On the other hand, in another embodiment, the processing unit 140 instead of generating an image to be utilized as a tool for directly determining the material by the user, the phase obtained for each measurement position in a predetermined measurement area of the measurement object MT , It is also possible to directly determine the material of the measurement object based on the average and the visibility. In this case, the criteria for determining various materials described above or the criteria for determining the state of the surface may be set as reference data in advance, and then the processing unit 140 may directly determine the reference data.

According to the lighting system as described above, a plurality of light sources are used to irradiate incident light from a plurality of directions to a measurement object, and control the light sources to be lit according to a dome-shaped sine wave pattern formed on the dome, thereby specifying the measurement object By calculating the phase at the measurement position, the average of the intensity of the reflected lights and the visibility of the reflected lights, the material of the measurement object can be easily determined.

In addition, unlike the conventional planar sine wave pattern, the dome type sine wave pattern can be formed on a dome-shaped hemisphere, so that the phase, the average, and the visibility are very accurate at any measurement position. Rather, since the absolute measurement value at each measurement position is very accurate, the relationship between each of the measurement positions can also have a very accurate value.

Accordingly, when the phase, the average, and the visibility, calculated as described above, are represented or processed as an image for material determination, a user can easily utilize them for material determination.

In addition, even if the intensity distribution of the reflected light is not directly obtained for material determination, the material determination may be possible based only on the information of the phase, the average, and the visibility.

In addition, the lighting system, in addition to the above-described material determination, may also determine the state of the surface, and may be utilized for defect determination and the like.

In addition, the phase, the average, and the invisibility calculated as described above, when the criteria for various material determination, the criteria for determining the condition of the surface, the criteria for determining the defect, etc. are set as reference data in advance, the material is directly processed by the processing unit Since it is possible to perform the determination, the status determination, and the failure determination, it is possible to improve the user's convenience and reliability.

In the detailed description of the present invention described above, the present invention has been described with reference to preferred embodiments of the present invention. And various modifications and changes of the present invention without departing from the technical scope. Accordingly, the foregoing description and the drawings below should be construed as illustrative of the invention rather than limiting the technical spirit of the invention.

100: lighting system 110: measuring stage
120: irradiation unit 130: light receiving unit
140: processing unit MT: object to be measured

Claims (12)

A measurement stage on which the measurement object is located;
It includes a plurality of light sources for irradiating incident light to the measurement object, respectively, the plurality of light sources are arranged to surround the top of the measurement object in the form of a dome so that the incident light from multiple directions to the measurement object is measured An irradiating unit capable of selectively irradiating toward the object;
A light receiving unit that acquires reflected light by the measurement object according to the incident lights irradiated by the irradiation unit; And
Includes a processing unit for controlling the light source to be lit according to a dome-shaped sine wave pattern (dome-shaped sine wave pattern);
The dome-shaped sine wave pattern is a sine wave pattern formed in a curved shape by controlling lighting of the light sources by the processing unit on a curved surface formed by the dome shape formed by the arrangement of the light sources,
The processing unit controls the light sources to be sequentially turned on by shifting the light sources N times according to the domed sinusoidal pattern for a specific measurement position of the measurement object (N is a natural number of 2 or more),
The irradiation unit generates the N pattern lights that are sequentially lit, and irradiates the measurement object,
The light receiving unit receives the N reflected lights of the N pattern lights irradiated to the measurement object,
The processing unit calculates, from the intensity of the N reflected lights, a phase at a specific measurement position of the measurement object, an average of the intensity of the N reflected lights, and the visibility of the N reflected lights,
Lighting system. According to claim 1,
The processing unit,
Characterized in that it generates image data for the measurement region including the measurement position based on the calculated phase, the average and the visibility,
Lighting system. According to claim 2,
The image data includes a gradient image in which a gradient of each pixel of the measurement object is expressed in grayscale based on the calculated phase, and a reflectance of a gray scale of reflectance of each measurement object in pixels based on the calculated average. Characterized in that it comprises an image and a roughness image representing the roughness of each pixel of the measurement object in grayscale based on the calculated visibility.
Lighting system. According to claim 1,
The processing unit,
Characterized by determining the material of the measurement object from the calculated phase, the average and the visibility,
Lighting system. According to claim 1,
The light sources of the irradiation unit,
Characterized in that each comprises a light-emitting diode (LED),
Lighting system. The method of claim 5,
The irradiation unit,
It is disposed on the upper portion of the measurement object to cover the periphery of the measurement object, characterized in that it further comprises an illumination cover in which the light emitting diodes are installed,
Lighting system. The method of claim 6,
The lighting cover has a shape including at least a portion of the dome (dome),
The light emitting diodes are provided in a ring shape having different diameters when viewed from the bottom, characterized in that formed in a plurality of rows (row) in the shape including at least a portion of the dome,
Lighting system. The method of claim 6,
The lighting cover,
Has an opening formed corresponding to the upper portion of the measurement object,
The light receiving unit is arranged to receive reflected light reflected from the measurement object through the opening.
Lighting system. The method of claim 8,
The irradiation unit,
A first irradiator for providing incident light to the measurement object from the light emitting diodes mounted on the illumination cover; And
Characterized in that it comprises a second irradiation unit for providing incident light to the measurement object through the opening formed in the lighting cover,
Lighting system. According to claim 1,
When the plurality of light sources are arranged at (r, θ, φ) coordinates on a spherical coordinate system centered on the measurement position of the measurement object,
The dome-shaped sine wave pattern is characterized in that the r-coordinate is constant, and a sine wave is formed on a hemisphere as the θ-coordinate in a specific φ-coordinate within a range of 0 to 90 degrees changes from 0 to 360 degrees.
Lighting system. According to claim 1,
When the plurality of light sources are arranged at (r, θ, φ) coordinates on a spherical coordinate system centered on the measurement position of the measurement object,
The dome-shaped sine wave pattern is characterized in that the r-coordinate is constant, and a sine wave is formed on a hemisphere as the φ-coordinate in a specific θ-coordinate within a range of 0 to 360 degrees changes from 0 to 90 degrees.
Lighting system. According to claim 1,
When the plurality of light sources are arranged at (r, θ, φ) coordinates on a spherical coordinate system centered on the measurement position of the measurement object,
The dome-shaped sine wave pattern is characterized in that the r-coordinate is constant, and a sine wave is formed on a hemisphere as the θ-coordinate changes from 0 to 180 degrees in a specific φ-coordinate within a range of -90 to 90 degrees,
Lighting system.

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