Variable neutral density filter system adjusting transmittance according to bright of light

Abstract

A variable ND filter system that automatically adjusts according to the brightness of light is provided, and includes a control device comprising: a sensor for measuring the brightness of a light source; a variable ND filter (Variable Neutral Density Filter) that adjusts the transmittance of the light source by the rotation angle of two polarizing filters; a motor for driving a dial for adjusting the rotation angle of two polarizing filters; a display for outputting status information of the variable ND filter; a receiving unit for receiving the brightness of the light source from the sensor; a driving unit for driving a motor to rotate the dial clockwise when the brightness exceeds a preset brightness; an extraction unit for determining the rotation angle and rotation direction of the dial and extracting an optical density that is mapped and stored to the rotation angle and rotation direction; and a transmission unit for transmitting status information including the optical density and the transmittance corresponding to the optical density to the display.

Description

Technology Field

[0001] The present invention relates to a variable ND filter system that automatically adjusts according to the brightness of light, and provides a system that automatically adjusts the transmittance of a variable ND filter according to the brightness of light. Background Technology

[0002] A Neutral Density Filter (ND filter) is a camera filter used in the fields of photography and optics that serves to evenly reduce the intensity of light. It allows for the reduction of light while maintaining color balance without changing the camera's shutter speed or aperture value, thereby helping to achieve proper exposure even in excessively bright environments. ND filters are generally attached to digital cameras to help take good photos in bright places, and they are also used in luminance measuring equipment such as point luminance meters or surface luminance meters to measure light brightness. Aids to Navigation (AtoN) are equipped with LED lanterns, and ND filters are also used when measuring the backlight luminance of lighting facilities in ports.

[0003] At this time, methods for linearly increasing or decreasing the transmittance of an ND filter or for creating an ND filter have been researched and developed. In this regard, prior art Korean Published Patent No. 2007-0104233 (published on October 25, 2007) and Korean Registered Patent No. 10-1111705 (published on February 15, 2012) disclose a configuration in which a gradient ND filter with continuously changing transmittance is arranged facing each other and inserted or removed symmetrically from the optical path to eliminate the characteristic of a gradient ND filter with non-uniform concentration depending on the location, and a configuration in which, when forming an ND filter, an optical film is formed on a transparent substrate and the optical film is formed by laminating the optical film with a light-absorbing film and a dielectric film, and the optical film has a transmittance that varies according to direction.

[0004] However, in the former case, only the configuration of a gradient ND filter is disclosed rather than a variable ND filter, and in the latter case, the configuration of a variable ND filter is disclosed, but since the transmittance of a variable ND filter is adjusted by turning a dial, not only is it impossible to set it to an accurate value because no precise numerical value appears on the dial, but it is also impossible to determine exactly what the current transmittance is. Accordingly, research and development of a system capable of checking the status information of a variable ND filter is required. The problem to be solved

[0005] One embodiment of the present invention can provide a variable ND filter system that automatically adjusts according to light brightness, wherein the brightness of a light source is collected using a sensor, and when the collected brightness exceeds a reference value, the dial of the variable ND filter is rotated clockwise, and the optical density and transmittance stored corresponding to the rotation angle and direction of the dial are extracted and displayed to identify and adjust the current status information of the variable ND filter, and furthermore, after analyzing the RGB histogram with the brightness data, the dial is driven to adjust the transmittance of the variable ND filter when at least one of R, G, and B is saturated, and this process is repeated until the RGB histogram moves out of the saturation area, thereby enabling automatic control while minimizing human intervention. However, the technical problem to be solved by this embodiment is not limited to the technical problem described above, and other technical problems may exist. means of solving the problem

[0006] As a technical means for achieving the technical problem described above, one embodiment of the present invention includes a control device comprising: a sensor for measuring the brightness of a light source; a variable neutral density filter for adjusting the light transmittance of the light source by the rotation angle of two polarizing filters; a motor for driving a dial for adjusting the rotation angle of two polarizing filters; a display for outputting status information of the variable neutral density filter; a receiving unit for receiving the brightness of the light source from the sensor; a driving unit for driving the motor so that the dial rotates clockwise when the brightness exceeds a preset brightness; an extraction unit for identifying the rotation angle and rotation direction of the dial and extracting an optical density that is mapped and stored to the rotation angle and rotation direction; and a transmission unit for transmitting status information including the optical density and the transmittance corresponding to the optical density to the display. Effects of the invention

[0007] According to any one of the means for solving the problem of the present invention described above, the brightness of a light source is collected using a sensor, and when the collected brightness exceeds a reference value, the dial of the variable ND filter is rotated clockwise, and the optical density and transmittance stored corresponding to the rotation angle and rotation direction of the dial are extracted and displayed, thereby enabling the current status information of the variable ND filter to be identified and adjusted. Furthermore, after analyzing the RGB histogram with the brightness data, if at least one of R, G, and B is saturated, the dial is driven to adjust the transmittance of the variable ND filter, and this process is repeated until the RGB histogram moves out of the saturated area, thereby enabling automatic control while minimizing human intervention. Brief explanation of the drawing

[0008] FIG. 1 is a drawing illustrating a variable ND filter system that automatically adjusts according to the brightness of light according to one embodiment of the present invention. FIG. 2 is a block diagram for explaining a control device included in the system of FIG. 1. FIGS. 3 and 4 are drawings for explaining an embodiment in which a variable ND filter is automatically adjusted according to an embodiment of the present invention. FIG. 5 is an operation flowchart illustrating a variable ND filter that is automatically adjusted according to the brightness of light according to one embodiment of the present invention. Specific details for implementing the invention

[0009] Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0010] Throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected" but also cases where they are "electrically connected" with other elements interposed between them. Furthermore, when a part is described as "including" a component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components, and it should be understood that this does not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0011] Terms such as “about,” “substantially,” etc., used throughout the specification, are used to mean at or near the stated value when inherent manufacturing and material tolerances are presented in the stated meaning, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure in which precise or absolute values ​​are mentioned to aid in understanding the invention. Terms such as “step” or “step of” used throughout the specification of the invention do not mean “step for”.

[0012] In this specification, the term "part" includes a unit realized by hardware, a unit realized by software, and a unit realized using both. Additionally, one unit may be realized using two or more pieces of hardware, and two or more units may be realized by one piece of hardware. Meanwhile, "part" is not limited to software or hardware, and "part" may be configured to reside in an addressable storage medium or configured to run on one or more processors. Accordingly, as an example, "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." In addition, the components and '~parts' may be implemented to play one or more CPUs within the device or secure multimedia card.

[0013] Some of the operations or functions described herein as being performed by a terminal, device, or device may instead be performed by a server connected to said terminal, device, or device. Likewise, some of the operations or functions described as being performed by a server may also be performed by a terminal, device, or device connected to said server.

[0014] In this specification, some of the operations or functions described as mapping or matching with a terminal may be interpreted as meaning mapping or matching the terminal's unique number or personal identification information, which is the terminal's identifying data.

[0015] The present invention will be described in detail below with reference to the attached drawings.

[0016] FIG. 1 is a drawing illustrating a variable ND filter system that automatically adjusts according to the brightness of light according to an embodiment of the present invention. Referring to FIG. 1, the variable ND filter system (1) that automatically adjusts according to the brightness of light may include at least one sensor (100), a control device (300), at least one motor (400), at least one variable ND filter (500), and a display (600). However, since the variable ND filter system (1) that automatically adjusts according to the brightness of light of FIG. 1 is merely an embodiment of the present invention, the present invention is not to be interpreted as being limited through FIG. 1.

[0017] In the following, the term "at least one" is defined as a term including both singular and plural forms, and it will be obvious that even if the term "at least one" does not exist, each component may exist in a singular or plural form and may mean singular or plural. Furthermore, whether each component is provided in a singular or plural form may be changed according to the embodiment.

[0018] FIG. 2 is a block diagram for explaining a control device included in the system of FIG. 1, and FIG. 3 and FIG. 4 are drawings for explaining an embodiment in which a variable ND filter is automatically adjusted according to an embodiment of the present invention.

[0019] Referring to FIG. 2, the control device (300) may include a receiving unit (310), a driving unit (320), an extraction unit (330), a transmission unit (340), a storage unit (350), and a saturation detection unit (360).

[0020] When a control device (300) according to one embodiment of the present invention or another server (not shown) operating in conjunction transmits a variable ND filter status information service application, program, app page, web page, etc. that automatically adjusts according to brightness to a user terminal (not shown), the user terminal may install or open the variable ND filter status information service application, program, app page, web page, etc. that automatically adjusts according to brightness. Additionally, a service program may be executed on the user terminal using a script executed in a web browser. Here, a web browser refers to a program that enables the use of web (WWW: World Wide Web) services and means a program that receives and displays hypertext described in HTML (Hyper Text Mark-up Language), and includes, for example, Chrome, Microsoft Edge, Safari, Firefox, Whale, UC Browser, etc. Additionally, an application refers to an application program on a terminal, and includes, for example, an app executed on a mobile terminal (smartphone).

[0021] Referring to FIG. 2, the receiver (310) can receive the brightness of the light source from the sensor (100). The sensor (100) can measure the brightness of the light source.

[0022] The driving unit (320) can drive the motor (400) so that the dial rotates clockwise when the brightness exceeds a preset brightness. The variable ND filter (500) (Variable Neutral Density Filter, 500) can adjust the transmittance of light from the light source by the rotation angle of two polarizing filters. The motor (400) can drive the dial for adjusting the rotation angle of the two polarizing filters.

[0023] <ND 필터>

[0024] Referring to FIG. 4a, ND filters other than variable ND filters (500) reduce the amount of light uniformly according to the number as shown in Table 1 below. When using an ND filter attached to equipment that measures light brightness, a method of correcting the measured value by multiplying by the transmittance is used. However, the type of filter used varies depending on how bright the light is; the stronger the light from the light source, the higher the value of the ND filter must be used. At this time, there are cases where the ND filter is repeatedly attached and detached to find a suitable ND filter depending on the brightness of the light source.

[0025] ND optical density F-stop Transmittance % ND2 0.3 1 50% ND4 0.6 2 25% ND8 0.9 3 12.50% ND16 1.2 4 6.25% ND32 1.5 5 3.12% ND64 1.8 6 1.56% ND128 2.1 7 0.78% ND256 2.4 8 0.39% ND500 2.7 9 0.20% ND1000 3 10 0.10% ND2000 3.3 11 0.05% ND32000 4.5 15 0.00% ND100K 6 20 0.00%

[0026] <ND 가변 필터> To address these inconveniences, a product called an ND variable filter, such as the one shown in Fig. 4b, has been released, but it is also difficult to set the exact value. Looking at Fig. 4b, it can be seen that grooves are carved into the outer edge, resembling concave and convex shapes. However, since no number, or optical density, is indicated on each of these grooves, it is not possible to accurately determine exactly what optical density is being set to, or what percentage the transmittance is.

[0027] Accordingly, one embodiment of the present invention can determine what the optical density is and what percentage the transmittance is when the dial of the variable ND filter (500) is rotated in a certain direction and by a certain angle based on a dataset of [dial-rotation direction-rotation angle-optical density-transmittance]. At this time, it is assumed that the rotation angle and rotation direction of the dial, as well as motor data such as the torque, speed, current, and voltage of the motor (400), are also stored together in the aforementioned dataset. That is, the control device (300) can map and store the rotation direction and rotation angle of the dial with the optical density and transmittance according to the polarizing filter. Here, the dial may be a mechanism such that the transmittance of the variable ND filter (500) decreases as it is rotated clockwise, and the transmittance of the variable ND filter (500) increases as it is rotated counterclockwise.

[0028] dial clockwise Increased optical density darkening Transmittance ↓ counterclockwise Optical density ↓ Brightening Transmittance ↑

[0029] <Reinforcement Learning> In one embodiment of the present invention, even if [Motor-Control Data]-[Dial-Rotation Direction-Rotation Angle]-[Variable ND Filter-Optical Density-Transmittance] are mapped and stored, it is not easy to adjust the motor in the small groove unit of the dial in FIG. 4b, for example, in the millimeter unit, and an error may always occur in the control. In this case, when a person readjusts the result of automatic control, the result can be fed back as a compensation value to PID control (Proportional-Integral-Derivative Control) or used in recent deep learning-based reinforcement learning to gradually update the control error. For example, let us assume that when the rotation direction of the dial is clockwise and the rotation angle is X, the dial value of the variable ND filter (500), that is, the optical density, must be 3.

[0030] At this time, there may be cases where the optical density does not become 3 even when the dial of the variable ND filter (500) is rotated clockwise by a rotation angle X through the motor (400). In the case where the target value is 3 and the actual value is 2, the control device (300) does not know that the actual value is 2, so it displays the target value of 3 on the display (600) and can provide a confirmation request to the user to check whether the scale number on the dial is 3. To this end, the control device (300) can be linked with an input device (not shown), and when the user inputs a scale number through the input device, reinforcement learning is performed based on the difference between [actual value - target value], and the motor can be controlled to minimize the control error. Here, since not all grooves in the dial have scale numbers, both the actual value and the target value must have scale numbers to be collected as a dataset for reducing the control error.

[0031] Reinforcement Learning

[0032] The Soft Actor Critic method can be utilized, consisting of an Actor that performs the search and a Critic that learns the correct direction based on the search results. The Actor receives the current parameter state, st, as input and uses it to determine the action at, which sets how the parameters will be changed next. This action decision is made through π(·) learning composed of a fully connected network. A reward rt is calculated for the changed parameter state based on the action, and the Critic can determine the final direction for parameter updates based on this reward function and the Actor's entropy. Of course, in addition to the method described above, various algorithms can be used to reduce control errors.

[0033] The extraction unit (330) can determine the rotation angle and rotation direction of the dial and extract the optical density that has been mapped and stored to the rotation angle and rotation direction. Optical density is a measure of the ability of a refractive medium or optical component to slow down or delay the transmission of light. In the variable ND filter (500), it refers to the numbers on the dial. Since the optical density numbers are not displayed in all grooves, they can be estimated based on the rotation angle and rotation direction according to the aforementioned dataset and database.

[0034] The transmission unit (340) can transmit status information including optical density and transmittance corresponding to optical density to the display (600). The display (600) can output status information of the variable ND filter (500). At this time, the status information may be optical density (dial number) and transmittance. In addition, information such as remaining battery capacity and light intensity may also be output.

[0035] The saturation detection unit (360) receives brightness data from the sensor (100), analyzes the RGB (Red, Green, Blue) histogram, and can determine whether at least one of R, G, or B in the RGB histogram is saturated. At this time, the RGB histogram is a graph that measures the brightness of an image and is based on the RGB color model, which consists of three basic components (channels) of red, green, and blue. The histogram displays the frequency of each tone as a bar chart value, where the horizontal axis represents brightness (black to white) and the vertical axis represents the frequency or intensity of each tone. The brightness of the image is measured through the RGB histogram, and problems such as black blurring or white blurring can be identified. If R, G, and B are each skewed to the right in the RGB histogram, it means that it is too bright and can be said to be saturated (when it is blurred into white).

[0036] Accordingly, as shown in (d) of FIG. 3a, the control device (300) adjusts the value (transmittance) of the variable ND filter (500) so that it reaches the center, which is an appropriate line that is not saturated in the RGB histogram. At this time, while adjusting the variable ND filter (500) with the motor (400), when the RGB histogram distribution reaches an area that is not saturated, the motor (400) stops the adjustment and can display the result. If the RGB histogram distribution remains in the saturated area, the motor (400) continues the adjustment until it moves out of the saturated area. Through this series of processes, the variable ND filter (500) can be automatically adjusted according to the brightness of the light. At this time, the driving unit (320) can rotate the dial of the variable ND filter (500) clockwise until at least one of R, G, and B is not saturated in the RGB histogram when at least one of R, G, and B is saturated. As described above, the motor (400) rotates the dial clockwise.

[0037] A variable ND filter system (1) that automatically adjusts according to the brightness of light may further include a battery that supplies power to a sensor (100), a motor (400), a display (600), and a control device (300). The control device (300) may also transmit the battery status of the battery to the display (600) for output. The variable ND filter system (1) that automatically adjusts according to the brightness of light according to the present invention may be implemented as a modular system using NVIDIA's Jetson, or implemented as an embedded system in luminance measuring equipment such as a point luminance meter or a surface luminance meter. FIG. 3b illustrates the data flow and power supply direction between each component of the variable ND filter system (1) that automatically adjusts according to the brightness of light according to an embodiment of the present invention.

[0038] Hereinafter, the operation process according to the configuration of the control device of FIG. 2 described above will be explained in detail with reference to FIG. 3 and FIG. 4. However, it is obvious that the embodiment is merely one of the various embodiments of the present invention and is not limited thereto.

[0039] Referring to FIG. 3, (a) a control device (300) receives brightness data from a sensor (100) and outputs an RGB histogram. Then, as in (b), it is determined whether the RGB histogram is saturated when compared to the appropriate graph of (c), and (d) if saturated, the variable ND filter (500) can be automatically controlled to automatically eliminate the phenomenon where too much light enters and the image becomes white by adjusting the dial of the variable ND filter (500) to lower the light transmittance. FIG. 4a is a general ND filter, and FIG. 4b is a variable ND filter.

[0040] Any details regarding the variable ND filter system that automatically adjusts according to brightness in FIGS. 2 to 4 that are not described are identical to or can be easily inferred from the description of the variable ND filter system that automatically adjusts according to brightness in FIG. 1, so further description will be omitted.

[0041] FIG. 5 is a diagram illustrating the process of transmitting and receiving data between each component included in a variable ND filter system that automatically adjusts according to the brightness of light in FIG. 1 according to an embodiment of the present invention. Hereinafter, an example of the process of transmitting and receiving data between each component will be described through FIG. 5, but the present invention is not to be interpreted as being limited to such an embodiment, and it is obvious to those skilled in the art that the process of transmitting and receiving data shown in FIG. 5 may be changed according to various embodiments described above.

[0042] Referring to FIG. 5, the control device receives the brightness of the light source from the sensor (S5100).

[0043] And, the control device drives a motor to rotate the dial clockwise when the brightness exceeds a preset brightness (S5200), determines the rotation angle and rotation direction of the dial, and extracts the optical density that has been mapped and stored to the rotation angle and rotation direction (S5300).

[0044] Additionally, the control device transmits state information including optical density and transmittance corresponding to optical density to the display (S5400).

[0045] The order of the steps described above (S5100~S5400) is merely an example and is not limited thereto. That is, the order of the steps described above (S5100~S5400) may vary, and some of these steps may be executed simultaneously or deleted.

[0046] Regarding the driving process of the variable ND filter system that automatically adjusts according to the brightness of light in Fig. 5, any details that are not described are identical to or can be easily inferred from the content described above through Figs. 1 to 4, so further explanation will be omitted.

[0047] A driving method for a variable ND filter system that automatically adjusts according to light brightness according to an embodiment described through FIG. 5 may also be implemented in the form of a recording medium containing computer-executable instructions, such as an application or program module executed by a computer. A computer-readable medium may be any available medium accessible by a computer and includes both volatile and non-volatile media, and both removable and non-removable media. Additionally, a computer-readable medium may include all computer storage media. A computer storage medium includes both volatile and non-volatile, removable and non-removable media implemented by any method or technique for storing information such as computer-readable instructions, data structures, program modules, or other data.

[0048] The method of operating a variable ND filter system that automatically adjusts according to the brightness of light according to one embodiment of the present invention described above may be executed by an application basically installed on a terminal (which may include a program included in a platform or operating system, etc., that is basically installed on the terminal), or by an application (i.e., a program) that is directly installed by a user on a master terminal through an application providing server, such as an application store server, an application, or a web server related to the service. In this sense, the method of operating a variable ND filter system that automatically adjusts according to the brightness of light according to one embodiment of the present invention described above may be implemented by an application (i.e., a program) that is basically installed on the terminal or directly installed by a user, and may be recorded on a computer-readable recording medium such as a terminal.

[0049] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0050] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

Claims

Claim 1 A sensor for measuring the brightness of a light source; a variable neutral density filter that adjusts the light transmittance of the light source by the rotation angle of two polarizing filters; a motor that drives a dial for adjusting the rotation angle of the two polarizing filters; and a display that outputs status information of the variable neutral density filter. and a control device comprising: a receiving unit for receiving the brightness of a light source from the sensor; a driving unit for driving the motor so that the dial rotates clockwise when the brightness exceeds a preset brightness; an extraction unit for determining the rotation angle and rotation direction of the dial and extracting the optical density that is mapped and stored to the rotation angle and rotation direction; a transmission unit for transmitting the state information, including the optical density and the transmittance corresponding to the optical density, to the display; a storage unit for mapping and storing the rotation direction and rotation angle of the dial and the optical density and transmittance according to the polarizing filter; and a saturation determination unit for receiving brightness data from the sensor, analyzing an RGB (Red, Green, Blue) histogram, and determining whether at least one of R, G, and B in the RGB histogram is saturated; wherein the dial is a mechanism such that the transmittance of the variable ND filter decreases as it rotates clockwise and increases as it rotates counterclockwise, and the driving unit, the R, A variable ND filter system that automatically adjusts according to the brightness of the light, wherein when at least one of G and B is saturated, the transmittance of the variable ND filter is adjusted so that the RGB histogram distribution moves out of the saturated region and the dial of the variable ND filter is rotated clockwise until at least one of R, G, and B in the RGB histogram is not saturated, and the variable ND filter system that automatically adjusts according to the brightness of the light comprises: a battery that supplies power to the sensor, motor, display, and control device;A variable ND filter system that automatically adjusts according to light brightness, further comprising, wherein the control device transmits the battery status of the battery to the display for output. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete

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