KR20160007208A - Method and Apparatus of Light Sensing Device for Controlling Lighting Device of Imaging Device - Google Patents

Abstract

Disclosed are a light sensing device for controlling a light emitting unit equipped in an image device, and a method for controlling a light emitting unit using the same. According to an aspect of the present invention, the light sensing device for controlling a light emitting unit equipped in an image device, comprises a light sensor, a control unit, and a timer which are connected to one another. The control unit includes a nonvolatile memory having a reference brightness value by time zone stored therein, wherein the control unit reads the reference brightness value corresponding to time information provided by the timer from the nonvolatile memory, and then compares a brightness value measured by the light sensor with the reference brightness value so as to control the light emitting unit of the image device.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a light sensing unit for controlling a light emitting unit provided in a video apparatus, and a control method of the light emitting unit using the light sensing unit.

The present embodiment relates to a light sensing apparatus for controlling a light emitting unit provided in a video apparatus and a control method of a light emitting unit using the same.

The contents described in this section merely provide background information on the present embodiment and do not constitute the prior art.

A light sensor is a sensor that converts light contained in light or information contained in light into an electric signal and detects the light by using a photoconductive effect or a photovoltaic effect. Typical optical sensors currently used include a CdS sensor and a digital ambient light sensor.

1 (a) is a cross-sectional view of a CdS sensor, and Fig. 1 (b) is a plan view of a CdS sensor.

CdS sensors are optical sensors that use a phenomenon that the conductivity of a material increases when the material absorbs light (photoconductive effect). In addition to CdS (cadmium sulfide) sensors, there are CdSe (cadmium selenide) sensors, PbS (lead sulfide) sensors, and ZnS (zinc sulfide) sensors.

2 is a circuit diagram illustrating a digital ambient light sensor.

A photodiode is a photosensor using a phenomenon (photovoltaic effect) in which an electromotive force is generated due to photo-excitation when a semiconductor having p-n junction is irradiated with light. In addition, there are phototransistors, photocouplers and digital ambient light sensors as optical sensors using photovoltaic effects.

An optical sensor and a control unit, and a device for controlling the image device according to the intensity of the sensed light is referred to as a light sensing device.

In recent years, there have been many video apparatuses which are equipped with a photodetector to improve user convenience and performance of the video apparatus. Particularly, most of the video devices installed outdoors such as electric signboards, outdoor displays, and CCTV are equipped with light sensing devices.

Since the ambient lighting maintains a relatively constant lighting condition in daytime or nighttime, the brightness of the surroundings does not change much, but outdoors, the light intensity rises sharply due to the sunlight during the daytime, and there is no extra illumination at nighttime. That is, the video apparatus fixedly installed outdoors needs to control the video apparatus by receiving a wide variation in brightness. In particular, due to the nature of outdoor, there are many cases where the video apparatus is left for a long time without a person to be managed. Therefore, a video apparatus with a photodetection device is required so that the video apparatus is automatically controlled according to the surrounding brightness without direct human control do.

In the present embodiment, the light emitting unit of the video apparatus is controlled in accordance with the time schedule, and when the brightness around the video apparatus deviates from the reference brightness value by a predetermined time or more, A light sensing unit for controlling the light emitting unit so as to reduce power consumption of the image sensing apparatus and obtain uniform image results without being affected by a temporal change in brightness, and a control method of a light emitting unit using the same. .

According to an aspect of the present invention, there is provided an optical sensing apparatus for controlling a light emitting unit provided in a video apparatus, the optical sensing apparatus including an optical sensor, a controller, and a timer connected to each other, Volatile memory, wherein the control unit reads the reference brightness value corresponding to the time information provided by the timer from the nonvolatile memory, and then reads the measured brightness value measured from the optical sensor and the reference brightness value And controls the light emitting unit of the image display device in comparison with the light emitting device.

According to another aspect of the present invention, there is provided a method of controlling a light emitting unit of a video apparatus by a light sensing device, comprising: reading a reference brightness value corresponding to a current date and time from a nonvolatile memory; Obtaining a measured brightness value by measuring the brightness around the current video device; And controlling the light emitting unit of the video apparatus by comparing the reference brightness value and the measured brightness value.

According to another aspect of the present invention, there is provided a light sensing device for controlling the brightness of a backlight of an LCD display, the light sensing device including an interconnected photo sensor, a controller, and a timer, Volatile memory, wherein the control unit reads the reference brightness value corresponding to the time information provided by the timer from the nonvolatile memory, and then reads the measured brightness value measured from the optical sensor and the reference brightness value And the brightness of the backlight of the LCD display is controlled.

According to another aspect of the present invention, there is provided an optical sensing device for controlling an infrared LED of a CCTV including an infrared LED, the optical sensing device including an optical sensor, a control unit, and a timer connected to each other, Volatile memory in which the brightness value is stored, and the controller reads a reference brightness value corresponding to the time information provided by the timer from the nonvolatile memory, and then reads the measured brightness value measured from the optical sensor and the reference brightness value And controls whether the infrared LED of the CCTV is turned on or off.

According to another aspect of the present invention, there is provided an optical sensing apparatus for controlling a light emitting unit provided in a video apparatus, the optical sensing apparatus comprising: an optical sensor for measuring ambient brightness; A timer for outputting time information; A control unit for selecting one of a plurality of operation modes for controlling the light emitting unit on the basis of time information output from the timer and outputting a control signal according to the selected operation mode to the light emitting unit, Wherein the control unit determines whether switching from the selected operation mode to another operation mode is requested based on the measured brightness value output from the optical sensor, And outputs a control signal according to the other operation mode to the light emitting unit.

According to the present embodiment, the light emitting unit of the image display device is normally controlled according to the time schedule, and when the brightness around the image display device deviates from the reference brightness value by a predetermined time or more, The power consumption of the video apparatus can be reduced, and a uniform video image can be obtained without being affected by temporal change in brightness.

1 (a) is a cross-sectional view of a CdS sensor, and Fig. 1 (b) is a plan view of a CdS sensor.
2 is a circuit diagram illustrating a digital ambient light sensor.
3 is a block diagram illustrating a conventional light sensing device.
4 is a block diagram illustrating an optical sensing apparatus according to an embodiment of the present invention.
5 is a flowchart illustrating a light sensing method according to the present embodiment.
6 is a diagram illustrating the structure of an LCD display.
7 is a side view illustrating a CCTV including an infrared LED.

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that, in the drawings, like reference numerals are used to denote like elements in the drawings, even if they are shown in different drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

In describing the constituent elements of this embodiment, first, second, i), ii), a), b) and the like can be used. Such a code is intended to distinguish the constituent element from other constituent elements, and the nature of the constituent element, the order or the order of the constituent element is not limited by the code. It is also to be understood that when an element is referred to as being "comprising" or "comprising", it should be understood that it does not exclude other elements unless explicitly stated to the contrary, do. Also, the terms 'module', 'module', and the like described in the specification mean units for processing at least one function or operation, and may be implemented as 'hardware' or 'software' or 'combination of hardware and software' have.

1. Characteristics of video equipment fixed outdoors

Recently, a photodetector is mounted on various image devices in order to improve user convenience and performance of a video apparatus. The light sensing device is a device that measures the amount of light according to natural light or illumination around the image device and controls the image device accordingly.

Imaging devices installed in a room such as a television, a computer, and a monitor are rarely produced by attaching a light sensing device because the ambient brightness is relatively constant.

However, portable image devices such as a smart phone and a camera are generally manufactured by attaching a light sensing device because the brightness of the surroundings varies greatly as the user moves.

In addition, video equipment fixedly installed outdoors such as electric signboards, outdoor displays, CCTV, etc., rapidly increases in illumination due to the sunlight during the day, darkens near to zero at night, and is often left unattended for a long time Therefore, it is general that a light sensing device is attached to the image sensing device so that the image sensing device can be automatically controlled according to the brightness of the surroundings without human control.

Comparing the portable image device and the fixed image device installed outdoors, the brightness of the image device is mainly changed according to the movement of the space in the portable image device, and the image device fixedly installed in the outdoor device is mainly in the vicinity of the image device It can be seen that the brightness changes.

Portable video devices such as smart phones and cameras can not predict the change in brightness because the brightness around the video device changes depending on the location of the portable device. Therefore, in the case of the portable image device, it is preferable to control the image device by reflecting the ambient brightness obtained from the normal light sensing device.

However, the image devices fixed to the outdoor such as the electric signboard, the outdoor display, and the CCTV are not moved, and the brightness around the image device changes according to the time of day and night, so that the change of brightness can be predicted in advance. Therefore, in the case of a video apparatus fixed outdoors, it is preferable to control the video apparatus using the expected brightness at normal times, and to control the video apparatus by reflecting the ambient brightness obtained from the light sensing apparatus only when necessary.

However, currently manufactured products control the image device by directly reflecting the ambient brightness obtained from the light sensing device, even if the image device is installed outdoors. That is, conventionally, by controlling the image device only by reflecting the ambient brightness obtained from the light sensing device without considering the portability of the image device, the position where the image device is installed, and the current time, unnecessary power wasting and performance destabilization There have been problems such as.

In this embodiment, a video device, particularly a video device fixedly installed outdoors, controls the video device in accordance with a predetermined time schedule, and if necessary, reflects the ambient brightness obtained from the photo- And a light sensing device and method for controlling the device.

2. Control method of light emitting unit using time scheduler and time scheduler

3 is a block diagram illustrating a conventional light sensing device.

The conventional light sensing device 300 includes a control unit 320, an optical sensor 330, and an analog-to-digital converter (ADC) 340.

The ambient light measured by the optical sensor 330 is converted into digital data through the ADC 340 and input to the control unit 320. [

The controller 320 selects the optimum operation mode according to the brightness value measured by the optical sensor 330 and controls the light emitting unit 310 according to the selected operation mode.

The light emitting unit 410 may be a backlight unit when the video apparatus is an LCD display, and may be an infrared LED unit when the video apparatus is CCTV.

The operation mode may be the brightness of the backlight unit determined according to the surrounding brightness value when the video apparatus is an LCD display and may be ON when the video apparatus is CCTV, / OFF.

4 is a block diagram illustrating an optical sensing apparatus according to an embodiment of the present invention.

The light sensing device 400 according to the present embodiment includes a control unit 420, an optical sensor 430, an ADC (Analog to Digital Converter) 440, and a timer 450.

The timer 450 provides the current date and time to the control unit 420 as a semiconductor module for displaying the current date and time in real time. Hereinafter, the information on the date or time provided by the timer 450 is referred to as 'time information'.

The control unit 420 includes a nonvolatile memory (not shown), and a nonvolatile memory (not shown) stores brightness values (hereinafter referred to as reference brightness values) according to the date and time.

The controller 420 controls the light emitting unit 410 based on the time information provided by the timer 450. Since the timer 450 and the control unit 420 control the light emitting unit 410 according to a time schedule, the timer 450 and the control unit 420 are collectively referred to as a time scheduler .

The control unit 410 controls the light emitting unit 410 based on the time information provided by the timer 450 as follows.

The control unit 420 reads a reference brightness value corresponding to the time information provided by the timer 450 from a nonvolatile memory (not shown), selects an optimum operation mode according to the reference brightness value, And controls the light emitting unit 410. The reference brightness value basically uses the value input by the manufacturer, but the user can directly input the brightness value. This is called a schedule control mode.

As another method, the control unit 420 may control the light emitting unit 410 according to an operation mode predetermined for each time period. For example, if the day is from 6:00 am to 6:00 pm and the night is from 6:00 pm to 6:00 am, the daytime operation mode can be activated during the day and the nighttime operation mode can be activated during the nighttime. The time mode operation mode basically uses the value input by the manufacturer, but the user can directly input the operation mode.

The light emitting unit 410 may be a backlight unit when the video apparatus is an LCD display, and may be an infrared LED unit when the video apparatus is CCTV.

The operation mode may be the brightness of the backlight unit determined according to the surrounding brightness value when the video apparatus is an LCD display and may be ON when the video apparatus is CCTV, / OFF.

In this embodiment, a method of controlling the light emitting unit 410 according to the reference brightness value among the two methods of controlling the light emitting unit 410 on the basis of the time information provided by the timer 450, .

The reference brightness value basically uses the value that the manufacturer inputs to the nonvolatile memory (not shown) when the product is manufactured.

However, since the brightness around the video apparatus may vary depending on the region where the video apparatus is installed, the position where the video apparatus is installed, and the like, it may be necessary to input the reference brightness value directly input by the user.

For example, when the video apparatus is always exposed to the outside, the illuminance rapidly increases due to direct sunlight when the video apparatus is in a low-light condition. On the other hand, when the video device is always covered by a building or a tree, the illuminance may be changed according to the direction of the shadow depending on the time.

Therefore, the optical sensing device of the present embodiment can directly input, modify, or delete the reference brightness value through a user interface (not shown) such as a keyboard, a mouse, and a touch screen. However, since it is troublesome for the user to input the reference brightness value, the control unit 420 of the time scheduler includes a function of automatically setting the reference brightness value.

The reference brightness value automatic setting function is a function for automatically storing a customized reference brightness value in a nonvolatile memory (not shown) of the control unit 420 without the user's direct input.

When the reference brightness value automatic setting mode is turned on, the control unit 420 of the time scheduler stores the brightness information obtained from the optical sensor in the nonvolatile memory (not shown) in units of M minutes for H hours. The values of H and M may be a value determined by the manufacturer or a value determined by the user. When the reference brightness value automatic setting mode is ON or H time elapses, the automatic reference brightness value setting mode is automatically turned off.

Even if the video device is fixed at the same position, the sun's altitude changes with time depending on the date, and the position of the shadows that cover the video device changes. Therefore, it is necessary to execute the reference brightness value automatic setting mode once a month.

However, it is very troublesome for the user to periodically execute the reference brightness value automatic setting mode periodically, so that the control unit 420 of the time scheduler includes a reference brightness value period setting function.

The reference brightness value period setting function is to automatically execute the reference brightness value automatic setting function at regular intervals even if the user does not execute the automatic reference brightness value setting function.

The reference brightness value period setting mode is ON, and it is set to 1 once a month, 2 times a month, 3 times a month ... When the execution cycle of the reference brightness value automatic setting mode is set by P number of times per month, the reference brightness value automatic setting mode is automatically executed every predetermined period.

In the optical sensing apparatus according to the present embodiment, the optical sensor 430 assists the function of the time scheduler. The ambient brightness measured by the optical sensor 430 is converted to digital data (hereinafter referred to as measured brightness value) through the ADC 440.

During the schedule control mode, the reference brightness value and the brightness value due to the appearance of obstacles blocking the image device, cloudy weather, rainy weather, snowy weather, automobile or airplane lights, unlit street lights, It is preferable to control the light emitting unit 410 using the measured brightness value instead of the reference brightness value.

When the reference brightness value and the measured brightness value are compared with each other and the difference between the two brightness values is equal to or more than L1 lux (lux) for more than T1 minutes, the control unit 420 determines, Lt; / RTI > The control of the light emitting unit 410 using the measured brightness value rather than the reference brightness value is referred to as a sensor control mode. L1 and T1, which are conditions for switching from the schedule control mode to the sensor control mode, can be appropriately adjusted by the manufacturer or the user in accordance with the application purpose of the image device and the characteristics of the region where the image device is installed.

In the sensor control mode, the controller 420 selects the optimum operation mode according to the measured brightness value, and controls the light emitting unit 410 according to the selected operation mode.

The light emitting unit 410 may be a backlight unit when the video apparatus is an LCD display, and may be an infrared LED unit when the video apparatus is CCTV.

The operation mode may be the brightness of the backlight unit determined according to the surrounding brightness value when the video apparatus is an LCD display and may be ON when the video apparatus is CCTV, / OFF.

During the sensor control mode, obstacles blocking the imaging device disappear, the clouds come off, the rain stops, the snow stops, the light of the car or airplane disappears, the light of the extinguished street light, the light of the lit street light go out If the difference between the reference brightness value and the measured brightness value remains below the proper level, it is preferable to control the light emitting unit 410 using the reference brightness value, not the measured brightness value again.

The controller 420 automatically switches from the sensor control mode to the schedule control mode when the difference between the brightness values of the reference brightness value and the measured brightness value is less than or equal to L2 lux (lux) And controls the light emitting unit 410 using the reference brightness value instead of the measured brightness value. L2 and T2, which are the conditions for switching from the sensor control mode to the schedule control mode, can be appropriately adjusted by the manufacturer or the user according to the application purpose of the image device and the characteristics of the region where the image device is installed.

When the reference brightness value automatic setting mode is ON, it means that the reference brightness value data is newly stored because the existing reference brightness value data is not reliable. Therefore, when the automatic setting mode of the reference brightness value is ON, the mode is forcibly changed to the sensor control mode, and the control unit 420 controls the light emitting unit 410 using the measured brightness value.

5 is a flowchart illustrating a light sensing method according to the present embodiment.

The light sensing method according to the present exemplary embodiment includes a reference brightness value automatic setting step S510, a schedule control step S520, a first sensor change condition determination step S521, a second sensor change condition determination step S523, A first schedule change condition determination process S531, a second schedule change condition determination process S533, and a forced sensor control process S540.

If the reference brightness value automatic setting mode is ON (NO in S510), the schedule control process (S520) is performed in the reference brightness value automatic setting process (S510) ') Force sensor control process (S540). The reason for performing the forcible sensor control process (S540) when the reference brightness value automatic setting mode is ON is that it is determined that the automatic setting mode is turned ON to newly store the reference brightness value because the previously stored reference brightness value information is not reliable to be.

When the reference brightness value automatic setting mode is ON or H time elapses, the automatic reference brightness value setting mode is automatically turned off. Therefore, there is no possibility that the forced sensor control process (S540) is repeated infinitely.

The schedule control process (S520) is a process for controlling the image device using the brightness value stored in the time scheduler. Specifically, the brightness value corresponding to the current date and time is read from the nonvolatile memory, and then the image device is controlled using the brightness value. The brightness value corresponding to the current date and time is referred to as a reference brightness value.

The sensor control process (S530) is a process for controlling the image device using the brightness value obtained from the optical sensor. The type of the optical sensor used in the sensor control process is not particularly limited, but a digital ambient light sensor is generally used for an LCD display, and a CdS sensor is generally used for a camera or a CCTV. The brightness value obtained from the optical sensor is called the measured brightness value.

The first sensor switching condition determination process S521 is a process for determining whether the reference brightness value and the measured brightness value are different from each other by L1 lux or more. The second sensor switching condition determination process S523 is a process for determining whether a state in which the reference brightness value and the measured brightness value are different from each other by L1 lux or more has continued for T1 minutes or more. If the reference brightness value and the measured brightness value are different from each other by L1 lux or more for more than T1 minutes, it is assumed that the reference brightness value is no longer reliable and the measured brightness value is used.

The first schedule change condition determination process S531 is a process for determining whether the reference brightness value and the measured brightness value are less than or equal to L2 lux. The second schedule change condition determination process (S533) is a process for determining whether a state in which the reference brightness value and the measured brightness value are less than or equal to L2 lux is longer than T2 minutes. If it is determined that the reference brightness value and the measured brightness value are different from each other by L2 lux or more for T2 minutes or longer, it is determined that the reference brightness value is within the error range of the measured brightness value. Even if there is an error, the reference brightness value is used for stable adjustment of the image device.

In the case of an LCD display, stable adjustment may mean providing a uniform brightness screen that is not affected by temporal changes in ambient brightness. In the case of CCTV equipped with an infrared LED, the stable adjustment may mean that the infrared LED is turned on due to a misidentification of the light sensing device during the day, and the normal image can not be obtained due to the switching to the black and white mode.

The forced sensor control process (S540) is a process for controlling the image device using the measured brightness value obtained from the optical sensor until the automatic setting mode of the reference brightness value is turned off. In the forced sensor control process, the image device is controlled using the brightness value obtained from the optical sensor without considering the difference between the reference brightness value and the measured brightness value.

Hereinafter, an application example of the optical sensing apparatus and method according to the present embodiment will be described.

3. Application to high brightness LCD display

BACKGROUND ART An LCD (Liquid Crystal Display) display is an image display device using a liquid crystal and is used in various image devices such as a television, a computer monitor, and a mobile phone.

The LCD display displays images on a regularly arranged panel of liquid crystals. In order to display an image using a liquid crystal, a light emitting device for illuminating the liquid crystal panel and a filter for expressing color are required because the liquid crystal itself does not emit light or color.

6 is a diagram illustrating the structure of an LCD display.

A backlight unit 630 is disposed behind the liquid crystal panel 620 of the LCD display and a color filter and a polarizing filter 610 are provided in front of the liquid crystal panel 620. In the liquid crystal device, the arrangement of molecules inside the liquid crystal varies according to an electric signal applied from the outside, and the liquid crystal has a certain directionality. Light transmitted from the backlight unit 630 passes through each liquid crystal and is refracted in different patterns. A color filter and a polarizing filter 610 in front of the liquid crystal panel 620 are passed through different angles to form one pixel having different colors and brightness. The pixels of different colors and brightness are gathered to form the entire screen.

In the LCD display, since the liquid crystal panel 620, the color filter, and the polarizing filter 610 do not emit light by themselves, the most important factor that determines the brightness of the LCD display is the backlight unit 630. In the past, a CCFL (Cold Cathode Fluorescent Lamp) was used as a backlight unit 630. However, since the LED has a longer lifetime than the CCFL and the LED does not change color even when used for a long time, the LED gradually replaces the CCFL .

In the case of an LCD display using the LED panel as the backlight unit 630, the brightness of the LCD display can be increased by turning on more LEDs or raising the voltage applied to the LEDs. Conversely, the brightness of the LCD display can be lowered by turning off the unnecessary LEDs or lowering the voltage applied to the LEDs.

LCD displays are divided into indoor and outdoor use depending on the maximum luminance. LCD displays used indoors have a brightness of 250 to 500 cd / ㎡, which is hard to see in outdoor sunlight. However, LCD displays installed outside are designed to look even under the sun with high brightness of over 1000 ~ 2000 cd / ㎡.

The LCD display installed outside the room may increase the number of LEDs of the backlight unit 630, change the polarizing filter 610 to a transflective polarizer, or optically bond the panels to light So as not to cause scattering of light. LCD displays designed with high brightness for outdoor use are called Sunlight Readable LCD Display, High Bright Panel LCD Display and Transflective LCD Display.

The LCD display installed outdoors must adjust the brightness to a large extent according to the change of the brightness around the day and night, or the user can not see the screen properly.

The brightness of the LCD display must be maximized during the day when the illuminance by the sunlight reaches its maximum value. On the other hand, after the sunset, there is no problem in checking the contents of the screen even if the brightness of the LCD display is reduced to 1/5, and the darkened state is more comfortable for the user to view the screen.

In places such as airports, seaports, airplanes, boats, and coastal surveillance centers, where there is little outside light at night, the ambient light level drops to almost zero after sunset. In this case, the brightness of the LCD display should also be adjusted to 0 The viewer can reliably check the contents of the screen.

In the brightness adjustment of the LCD display fixed to the outdoors, although the brightness of the LCD display can be adjusted using only the brightness value obtained from the optical sensor, in this case, the brightness of the screen is brightened and darkened due to the change of the ambient brightness repeatedly , Attention is distracting and eyes can easily become tired.

However, when the light sensing device of this embodiment is attached to the LCD display fixed to the outdoors, the brightness of the screen is relatively stably maintained, so that distraction and eye fatigue due to temporal change in ambient brightness can be prevented.

When an airplane passes through the airport at night and the light of an airplane brightens around the LCD display momentarily, if the brightness of the LCD display is adjusted using only the brightness value obtained from the light sensor, the LCD display suddenly becomes bright, The user can not reliably display the contents to be displayed. Therefore, in this case, it is preferable to adjust the brightness of the LCD display according to the operation mode set by the time schedule.

However, if the airplane keeps on stopping and the airplane lights continue to illuminate the LCD display, it is desirable to adjust the brightness of the LCD display using the brightness value obtained from the optical sensor.

The operation process when the light sensing device of the present embodiment is applied to the high brightness LCD display is as follows.

When the brightness value selected by the time scheduler among the reference brightness value or the measured brightness value is darker than the brightness value of the current LCD display, Darken it.

On the other hand, when the brightness value selected by the time scheduler among the reference brightness value or the measured brightness value is brighter than the brightness value used as the brightness adjustment reference of the current LCD display, Lt; / RTI >

A process of storing a reference brightness value, a process of selecting a brightness value to be used for controlling an LCD display from a reference brightness value and a measured brightness value, and the like are described in Table 2 'Control method of a light emitting unit using a time scheduler and a time scheduler' And therefore it will be omitted.

4. Application to CCTV including infrared LED

In the modern society, CCTV (Closed Circuit Television) is widely used for the purpose of checking the operation state of the machine or the flow of the process at the factory or for access control or security in offices, department stores, exhibition halls, houses, .

CCTVs installed outdoors can not obtain clear images due to lack of light at night. Even if a streetlight is installed around the CCTV, if the light of the streetlight is weak or the streetlight fails, a clear image can not be obtained.

Therefore, if the surroundings of the CCTV become dark enough to make things difficult to see, you should turn on the lights to get clear images. At this time, it is possible to turn on the fluorescent lamp or the bulb to brighten the surroundings of the CCTV. However, when the fluorescent lamp or the bulb is continuously turned on at night, power consumption is considerable. Therefore, after attaching an infrared LED to a CCTV, a CCTV that records in a monochrome mode using infrared rays reflected from an object is now on the market.

7 is a side view illustrating a CCTV including an infrared LED.

CCTVs including infrared LEDs are generally designed in such a manner that a camera module 710 is disposed at the center and a camera module 710 is surrounded by a lamp type infrared LED 720 in a ring shape. The light sensor 730 measures the brightness around the CCTV. The control unit (not shown) turns the infrared LED 720 ON / OFF according to the measured brightness.

During the day, turn off the infrared LED (720) and shoot in color mode using visible light. When the infrared LED 720 is turned on during the day, the camera recognizes the light of the infrared wavelength band and the color of the image changes. Therefore, the infrared LED 720 must be turned off during the color mode photographing.

On the other hand, at night, the infrared LED (720) is turned on and the image is taken in black and white mode using infrared rays.

It is possible to determine whether the infrared LED 720 is ON or OFF using only the brightness value obtained from the optical sensor 730 in adjusting the infrared LED 720. However, if only the brightness value obtained from the optical sensor 730 is used, An abnormal image can be obtained due to a sudden change in ambient brightness. The infrared LED 720 is turned on and the infrared LED 720 is turned off or the infrared LED 720 is turned off and the infrared LED 720 is suddenly turned on, The color of the image may be changed or the sharpness of the image may be deteriorated.

However, when the light sensing device of this embodiment is attached to the CCTV including the infrared LED 720, it is possible to prevent the change of the color of the image and the sharpness of the image according to the temporal change of the ambient brightness, Is stably maintained.

For example, when the CCTV including the infrared LED 720 is installed in the parking lot entrance, if the infrared LED 720 is adjusted using only the brightness value obtained from the optical sensor 730, The infrared LED 720 turns off and turns into a color mode, and when the car passes, the infrared LED 720 turns on and changes to a black and white mode, thereby causing a confused image to be recorded. Therefore, in this case, it is preferable to determine whether the infrared LED 720 is turned on or off according to an operation mode determined by a time schedule. That is, if the time zone is low, the infrared LED 720 is turned off, and if the time zone is nighttime, the infrared LED 720 is turned on.

However, when the car is continuously stopped and the car light is continuously illuminating the CCTV, it is preferable to determine whether the infrared LED 720 is turned on / off by using the brightness value obtained from the optical sensor 730.

An operation process when the light sensing device of this embodiment is applied to the CCTV including the infrared LED 720 is as follows.

When the brightness value (hereinafter referred to as reference brightness value) selected by the time scheduler among the reference brightness value or the measured brightness value is equal to or greater than a brightness value capable of color mode recording, the infrared LED 720 is turned off and color mode recording is started.

On the other hand, when the reference brightness value is less than or equal to the brightness value capable of color mode recording, the infrared LED 720 is turned on to start the monochrome mode recording.

A process of storing a reference brightness value, a process of selecting a brightness value to be used for controlling an LCD display from a reference brightness value and a measured brightness value, and the like are described in Table 2 'Control method of a light emitting unit using a time scheduler and a time scheduler' And therefore it will be omitted.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

In particular, although the present embodiment is applied only to the CCTV including the LCD display and the infrared LED fixed in the outdoors, it is installed near the window such as the control tower of the airport, The technical idea of the present embodiment can be used as it is.

The present invention is not intended to limit the scope of the present invention but to limit the scope of the present invention. The scope of protection of the present invention should be construed according to the claims, and all technical ideas considered to be equivalent or equivalent thereto should be construed as being included in the scope of the present invention.

300: light sensing device 310: light emitting unit
320: Control section 330: Light sensor
340: ADC 400: optical sensing device including time scheduler
410: light emitting unit 420:
430: optical sensor 440: ADC
450: timer 610: color filter and polarizing filter
620: liquid crystal panel 630: backlight unit
710: Camera module 720: Infrared LED
730: Light sensor

Claims (24)

A light sensing device for controlling a light emitting unit provided in a video device,
Wherein the light sensing device comprises an interconnected optical sensor, a control and a timer,
Wherein the control unit includes a nonvolatile memory storing a reference brightness value for each time period,
Wherein the control unit reads the reference brightness value corresponding to the time information provided by the timer from the nonvolatile memory and then compares the measured brightness value measured from the photosensor with the reference brightness value, Wherein the control unit controls the light source. The method according to claim 1,
Wherein the control according to the comparison between the measured brightness value and the reference brightness value comprises:
When the state in which the difference between the measured brightness value and the reference brightness value is equal to or greater than the first preset preset value L1 is greater than or equal to the first preset value T1, However,
If the state in which the difference between the measured brightness value and the reference brightness value is equal to or less than the second preset preset value L2 is equal to or greater than the second preset value T2, Wherein the light sensing device comprises: The method according to claim 1,
Wherein the light sensing device further comprises a user interface that allows the user to set the reference brightness value directly. The method of claim 3,
Wherein the control unit receives brightness information obtained from the optical sensor when the reference brightness value automatic setting command is input from the user interface to the nonvolatile memory of the control unit for a predetermined second time (H) Store,
And terminates the reference brightness value automatic setting operation when the first time has elapsed since the start of the operation of automatically setting the reference brightness value. 5. The method of claim 4,
Wherein the controller is configured to automatically set the reference brightness value in a predetermined period when the reference brightness value period setting command is received from the user interface. 5. The method of claim 4,
Wherein the control unit controls the light emitting unit of the video apparatus according to the measured brightness value without comparing the measured brightness value and the reference brightness value during the operation of automatically setting the reference brightness value. A method of controlling a light emitting unit of a video device by a light sensing device,
Reading a reference brightness value corresponding to a current date and time from a nonvolatile memory;
Obtaining a measured brightness value by measuring the brightness around the current video device; And
Comparing the reference brightness value with the measured brightness value and controlling the light emitting unit of the video apparatus
And controlling the light emitting unit to emit light. 8. The method of claim 7,
And comparing the measured brightness value with the reference brightness value,
A schedule control process of controlling a light emitting unit of the video apparatus according to the reference brightness value; And
And controlling a light emitting unit of the video apparatus according to the measured brightness value,
When the state in which the difference between the reference brightness value and the measured brightness value is equal to or more than the first preset illumination value L1 is longer than the first preset time value T1,
And performs a schedule control process when a state in which the difference between the reference brightness value and the measured brightness value is equal to or less than a second preset preset value L2 continues for a second preset value T2 or longer. A method of controlling a unit. A light sensing device for controlling a brightness of a backlight of an LCD display,
Wherein the light sensing device comprises an interconnected optical sensor, a control and a timer,
Wherein the control unit includes a nonvolatile memory storing a reference brightness value for each time period,
The controller reads the reference brightness value corresponding to the time information provided by the timer from the nonvolatile memory and then compares the measured brightness value measured from the photosensor with the reference brightness value to calculate the brightness of the backlight of the LCD display And a control unit for controlling the light emitting device. 10. The method of claim 9,
Wherein the control according to the comparison between the measured brightness value and the reference brightness value comprises:
If the difference between the measured brightness value and the reference brightness value is greater than or equal to the first preset preset value L1 for the first preset time value T1, the brightness of the backlight of the LCD display is changed according to the measured brightness value Control,
If the difference between the measured brightness value and the reference brightness value is equal to or less than the second preset preset value L2 is equal to or greater than the second preset value T2, the brightness of the backlight of the LCD display Wherein the control unit controls the light source to control the light source. 10. The method of claim 9,
Wherein the controller further comprises a user interface for allowing the user to directly set the reference brightness value. 12. The method of claim 11,
Wherein the control unit receives brightness information obtained from the optical sensor when the reference brightness value automatic setting command is input from the user interface to the nonvolatile memory of the control unit for a predetermined second time (H) Store,
And terminates the reference brightness value automatic setting operation when the first time has elapsed since the start of the operation of automatically setting the reference brightness value. 13. The method of claim 12,
Wherein the control unit includes a reference brightness value period setting function,
Wherein the controller is configured to automatically set the reference brightness value in a predetermined period when the reference brightness value period setting command is received from the user interface. 13. The method of claim 12,
Wherein the control unit controls the light emitting unit of the video apparatus according to the measured brightness value without comparing the measured brightness value and the reference brightness value during the operation of automatically setting the reference brightness value. A light sensing device for controlling an infrared LED of a CCTV including an infrared LED,
Wherein the light sensing device comprises an interconnected optical sensor, a control and a timer,
Wherein the control unit includes a nonvolatile memory storing a brightness value for each time period,
The control unit reads the reference brightness value corresponding to the time information provided by the timer from the nonvolatile memory and then compares the measured brightness value measured from the photosensor with the reference brightness value to determine whether the infrared LED of the CCTV is ON / OFF " is controlled. 16. The method of claim 15,
Wherein the control according to the comparison between the measured brightness value and the reference brightness value comprises:
When the difference between the measured brightness value and the reference brightness value is greater than or equal to the first preset illuminance value L1 for the first preset time value T1 or more, OFF,
When the state in which the difference between the measured brightness value and the reference brightness value is equal to or less than the second preset lighting value L2 is greater than or equal to the second preset time value T2, OFF state of the photodetector. 16. The method of claim 15,
Wherein the light sensing device further comprises a user interface that allows the user to set the reference brightness value directly. 18. The method of claim 17,
Wherein the control unit receives brightness information obtained from the optical sensor when the reference brightness value automatic setting command is input from the user interface to the nonvolatile memory of the control unit for a predetermined second time (H) Store,
And terminates the reference brightness value automatic setting operation when the first time has elapsed since the start of the operation of automatically setting the reference brightness value. 19. The method of claim 18,
Wherein the controller is configured to automatically set the reference brightness value in a predetermined period when the reference brightness value period setting command is received from the user interface. 19. The method of claim 18,
Wherein the control unit controls the light emitting unit of the video apparatus according to the measured brightness value without comparing the measured brightness value and the reference brightness value during the operation of automatically setting the reference brightness value. A light sensing device for controlling a light emitting unit provided in a video device,
An optical sensor for measuring ambient brightness;
A timer for outputting time information;
A control unit for selecting one of a plurality of operation modes for controlling the light emitting unit on the basis of time information output from the timer and outputting a control signal according to the selected operation mode to the light emitting unit, , ≪ / RTI &
Wherein the control unit determines whether switching from the selected operation mode to the other operation mode is requested based on the measured brightness value output from the optical sensor, and when the switch to the other operation mode is requested, And outputs the control signal to the light emitting unit. 22. The method of claim 21,
And a user interface for setting any one of the plurality of operation modes for each of the time zones. 22. The method of claim 21,
Wherein,
Reads the reference brightness value corresponding to the time information output from the timer from the nonvolatile memory, and compares the measured brightness value output from the photosensor with the reference brightness value to determine whether switching of the operation mode is required And a light source for emitting light. 24. The method of claim 23,
And switches the operation mode when the measured brightness value output from the optical sensor is greater than a preset time based on the reference brightness value.

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