KR102041346B1 - Electric signboard and electric signboard system for improving visibility and image quality - Google Patents

Abstract

The present invention relates to an electronic signboard and electronic signboard system for improving the visibility and image quality. More specifically, the present invention relates to the electronic signboard and electronic signboard system capable of improving the visibility and image quality by adjusting the contrast and a gamma value displayed on the signboard in response to the brightness of the signboard installed outside. The electronic signboard comprises: a light tracking sensor tracking a position of a light source; and an electronic signboard body displaying an image in which at least one of the contrast and gamma value is adjusted according to the position of the light source sensed by the light tracking sensor.

Description

Electric signboard and electric signboard system for improving visibility and image quality}

The present invention relates to an electric signboard and an electric signboard system for improving visibility and image quality, and more particularly, to adjust the contrast and gamma values of an image displayed on the signboard in response to the brightness around the signboard installed outdoors. The present invention relates to an electric signboard and an electric signboard system that can be improved.

Light Emitting Diode (LED) refers to a light emitting diode that emits light and emits light of various colors such as red, green, and blue. Such LEDs are used as electronic display panels of various electronic products and instrument panels. Also, by arranging a plurality of LEDs in a tiled manner, an LED display board in which an image is displayed may be realized by lighting all or some of the LEDs.

In general, the electric signboard is composed of a combination part (hereinafter referred to as a screen) and an edge bezel of the module for displaying an image.

Like most display devices, the display board has black screen and bezel parts other than the light source, thereby minimizing light reflection to external light sources to prevent glare and improve the concentration of the content displayed on the screen.

In the case of a home TV installed indoors, since the brightness of the external light source is not high, the bezel part has no surface reflection, so the bezel may be used as a gray lamp in consideration of product design, but it is generally composed of black.

In the case of such TVs and monitors, many technical improvements have been made to reduce the light reflection on the surface portion of the screen to increase the clarity of the image quality.

In the case of an electronic board, the surface of the module consists of an array of LEDs and a plastic grille cover. In this case, LED products with small lens size may be used to reduce light reflection of the LED lens part, and since most of the module surface is occupied by the grill cover, the cover of the cover may be reduced to reduce the light reflection of the grill cover part to the position where the image is viewed. It also forms various patterns to turn the light reflection on the surface in different directions, and a shade shade is formed on the top where the LED is located to reduce the light reflection on the surface of the LED lens.

In addition, we are trying to reduce the surface reflection as much as possible by coating in matte black.

The display board is 10 times brighter than indoors and 20 times brighter than outdoor TVs to provide clear visibility even in bright surroundings. However, despite the high brightness screen, it has a problem of deterioration of visibility due to surface light reflection by an external light source such as sunlight.

In particular, in the case of a signboard installed on the road or on the side of the road, the reflection of the surface may interfere with the driver's vision, leading to a risk of an accident, and may fail to perform its intended purpose due to lack of accurate information on emergency situations.

Conventional display boards are equipped with a light sensor on the outside of the display board and has a multi-level screen brightness adjustment function according to the illuminance value. When the ambient light is brighter, the screen brightness can be increased to provide an ideal screen brightness for the pupil of an extended person according to the light intensity. This brightness adjustment is usually processed with data obtained from one illuminance sensor installed (in the case of a double-sided display, which can be handled by two sensors for independent control of the screen, respectively), which is installed on the front of the display. It reacts according to the illuminance value toward which it is directed, and can produce a value which can correspond to the front irradiation light. In this case, however, the headlight or streetlight of the vehicle may generate data such as an increase in illuminance, thereby increasing the risk of a driver accident due to sudden high brightness display at night.

In response to this, when the illuminance sensor is installed on the upper or side part of the display board, it is more difficult to accurately adjust the screen brightness of the display board corresponding to the position of sunlight.

In this way, if the brightness of the screen is increased only as the ambient illumination increases, it becomes more difficult to distinguish between the bright and dark parts of the graphic displayed on the screen, and the sharpness of the displayed image or text becomes worse.

Republic of Korea Patent Publication No. 10-0812467 (2008.03.10.) Republic of Korea Patent Publication No. 10-0914209 (2009.08.26.) Republic of Korea Patent Publication No. 10-0914210 (2009.08.26.)

The present invention is to solve the problem that the visibility of the screen display image (contents) is lowered by the external light is reflected on the front portion located on the screen of the electronic screen, the screen brightness simply according to the ambient light regardless of the direction of the external light source It aims at improving the fall of the image quality and visibility which arise by adjusting only.

In order to achieve the above object, the display board for improving the visibility and image quality of the present invention, the light tracking sensor for tracking the position of the light source and at least one of the contrast and the gamma value is adjusted according to the position of the light source detected from the light tracking sensor It consists of an electronic display board that displays the captured image.

Specifically, the light tracking sensor is a light tracking camera that tracks the position of the light source and measures the brightness of light incident from the light source.

In addition, the display board for improving visibility and image quality of the present invention further includes an illuminance sensor installed on the display board body to measure the ambient brightness of the display board body, the display board body and the light brightness measured by the light tracking camera The brightness of the light measured by the illuminance sensor is compared to display an image in which the contrast or gamma value is adjusted according to the brightness of the corrected light.

On the other hand, the display board system for improving the visibility and image quality of the present invention, the display board having an LED module for displaying an image; An optical tracking sensor which tracks the position of the light source outside the electronic sign and measures the brightness of the light incident from the light source; A control unit receiving light source information from the light tracking sensor and generating image data displayed on the electronic display board; And a display controller which receives the image data from the controller, converts the image data into a data format for display on the electronic display board, and drives the LED module, wherein the controller or display controller is configured to obtain the optical tracking sensor. Based on the information of the light source, the contrast and the gamma value of the image displayed on the display board are adjusted.

The control unit may include an analysis controller that receives light source information from the light tracking sensor and generates image correction data for adjusting the contrast or gamma value of the image, and a control PC that receives the image correction data from the analysis controller.

The control unit may include a control PC for generating image data displayed on the display board, and a graphic card provided at the control PC or connected to the control PC to adjust the contrast or gamma value of the image data.

In addition, the display board system for improving visibility and image quality of the present invention further includes an illuminance sensor for measuring the brightness around the sign, the controller or display controller is the brightness of the light measured by the light tracking sensor and the illuminance sensor The brightness and the gamma value of the image displayed on the display board are adjusted according to the brightness of the light corrected by comparing the brightness of the light measured by.

The signboard and signboard system for improving the visibility and image quality of the present invention can automatically improve the picture quality and visibility of the signboard by converting the brightness, contrast, and gamma values of the image according to external circumstances such as brightness and light irradiation around the signboard. .

1 is a perspective view of an electronic sign according to an embodiment of the present invention.
Figure 2 is a perspective view of the LED module according to an embodiment of the present invention.
3 is a view illustrating a signboard system configuration according to an embodiment of the present invention.
4 is a schematic view of a signboard system configuration according to another embodiment of the present invention.
5 is a diagram illustrating contrast adjustment according to an embodiment of the present invention.
6 is an exemplary gamma adjustment according to an embodiment of the present invention.
7 is a view schematically showing the internal structure of the optical tracking camera according to an embodiment of the present invention.
8 is a view illustrating comparison of angles of view according to types of lenses;
9 is a diagram showing an example of correcting a distorted image according to an embodiment of the present invention.

In order to increase the sharpness of the image in response to the light reflection of the electronic screen, grasping the position, angle, and brightness of the external light source must be preceded.

In general, the display board attaches light-receiving elements such as CDS, Photo TR, and Photo Diode to the front or top of the display board to grasp the illumination condition of the external light source affecting the screen of the display board.

Since the illuminance sensor using the light receiving element merely grasps the intensity of the external light source, it provides inaccurate information according to the location of the external light source and the irradiation angle of the light by the external light source, and increases or decreases the screen brightness based on the incorrect information. It can't be done outside. Accordingly, the image displayed on the screen of the electronic display panel may not be precisely adjusted to the external environment, and there is a limit to improving the image quality and visibility of the image.

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

According to an exemplary embodiment of the present invention, the electronic display panel capable of improving the image quality and visibility may include an electronic display panel 101 and an optical tracking sensor 200 as illustrated in FIGS. 1 and 2.

The electric sign main body 101 includes a plurality of LED modules 100 and a bezel 120 surrounding the edge of the LED module 100 so that the LED modules 100 are exposed to the front. The electric signboard body 101 displays an image in which at least one of contrast and gamma values is adjusted according to the position of the light source detected by the light tracking sensor 200. A detailed image correction method will be described later together with the electronic display system.

The light tracking sensor 200 is mounted on the upper plate body 101. That is, the light tracking sensor 200 is mounted on the upper portion of the bezel 120. In addition, the light tracking sensor 200 may be configured to be separated from the electronic sign body 101. The light tracking sensor 200 detects and tracks the position of the light source that is outside of the electric light plate main body 101. The light source to be tracked by the light tracking sensor 200 is generally the sun in the case of the outdoor display board 100, and may be artificial lighting.

Specifically, the light tracking sensor 200 may be a light tracking camera that tracks the position of the light source and measures the brightness of light incident from the light source. In the optical tracking camera, as shown in FIG. 7, an image cell (imaging device 510) installed inside the optical tracking camera detects the light incident from the light source through the lens 520 to track the position of the light source and brightness of the light. Measure

As described above, the position of the light source incident on the display board can be determined based on the installation position and the direction of the display board using the position of the light source detected by the image cell.

Meanwhile, as shown in FIG. 8, in the case of the lens 520 having a wide angle of view (AV), the tracking range of the light source is wider, but the position of the light source detected in the image cell is distorted as the lens 520 of the wide angle of view (AV) is wider. Since it is detected as shown in Fig. 9, such distortion must be corrected to calculate the actual position.

In FIG. 8, (a) is telephoto, (b) is standard, and (c) is wide angle. FIG. 9 (d) shows a distorted image as a photographed image, FIG. 9 (e) shows a distortion correction factor for correcting an image, and FIG. 9 (f) shows a normal image generated by correction.

In this case, the electronic sign 100 of the present invention may further include an illuminance sensor (not shown) installed in the electronic sign main body 101 to measure the ambient brightness of the electronic sign main body 101. Accordingly, the electronic display body 101 compares the brightness of the light measured by the light tracking camera with the brightness of the light measured by the illuminance sensor and displays an image in which the contrast or gamma value is adjusted according to the brightness of the corrected light.

Lenses applied to optical tracking cameras may use different lenses such as general lenses, wide-angle lenses, and fisheye lenses, depending on the conditions of the installation site. Since there is a difference in the brightness of the lens, correction processing for distortion or sensitivity generated according to the specifications of the lens used may be necessary.

In addition, as another embodiment of the present invention, the light tracking sensor 200 may be composed of a plurality of light emitting elements positioned to correspond to a plurality of pipes and a plurality of pipes (not shown) that are opened in different directions. The light tracking sensor 200 may detect the position of the light source by comparing and analyzing the outputs of the plurality of light receiving elements. That is, the intensity of light incident on the light receiving element through each tube varies according to the position of the light source, and thus, the output difference of each light receiving element occurs. These differences in output can be compared and analyzed to detect and track the position of the light source.

According to another embodiment of the present invention, the light tracking sensor 200 may be formed of a cover and a light receiving module (not shown). The cover covers the light receiving module, and a plurality of perforations are formed in the cover. The cover is formed in a curved shape so that the plurality of perforations formed in the cover face different directions. Accordingly, the light incident on the light receiving module through the plurality of perforations is changed according to the position of the light source and the light intensity, and the light receiving module detects such a difference so that the light tracking sensor 200 can determine the position of the light source. have.

The signboard system that can improve the image quality and visibility including the signboard body 101 described above, as shown in Figures 3 to 6, the signboard 100, the light tracking sensor 200, the illumination sensor (not shown) , Control unit 300, and display controller 400.

The electronic display panel 100 includes a plurality of LED modules 100 for displaying an image.

The light tracking sensor 200 tracks the position of the light source on the outside of the electric sign 100 and measures the brightness of the light incident from the light source. The light tracking sensor 200 may selectively apply any one of the above-described embodiments of the light tracking sensor 200. Hereinafter, the light tracking sensor 200 will be described as an example of the light tracking camera.

The illuminance sensor measures the brightness around the electric sign 100 separately from the light tracking sensor 200. Accordingly, the control unit 300 or the display controller 400 compares the brightness of the light measured by the light tracking sensor 200 with the brightness of the light measured by the illuminance sensor. Adjust the contrast and gamma value of the image displayed in.

As described above, the position of the light source is detected and tracked using the light tracking camera, and the brightness of the external light source is corrected by comparing the brightness of the light measured by the light tracking camera with the brightness of the light measured by the illuminance sensor. By accurately analyzing the position, the angle of light incident from the light source to the electronic sign 100, and the brightness around the electronic sign 100, the image displayed by the electronic sign 100 may be corrected to an optimal image quality. Accordingly, the visibility of the electronic display panel 100 may be improved, and a driver accident may be prevented by blocking sudden display of a high brightness screen.

As described above, when the wide viewing angle lens is used, the light source can be tracked in a wide range, but distortion of the image photographed by the optical tracking camera occurs. This distortion of the image is difficult to determine the exact position of the light source because the error of the position of the light source occurs when converting the image coordinate to physical coordinates in order to track the exact position of the light source.

The distortion of the image by the lens is largely radial and tangential distortion. In the present invention, it is mainly caused by the refractive index of the convex lens, and the degree of distortion is affected by the radiation distortion, which is determined by the distance from the center.

When there is no distortion of the lens system, one point (Xc, Yc, Zc) in the three-dimensional space is projected to one point (x _{n_u} , y _{n_u} ) on the normalized image plane as shown in Equation (1) _below . do.

Equation (1)

However, in reality, distortion occurs due to nonlinearity of the lens system, and a point (x _{n_d} , y _{n_d} ) in which the distortion of the lens system is reflected is _{expressed by} Equation (2) below.

Equation (2)

(k ₁ , k ₂ is the radial distortion coefficient,

r _u is the distance (radius) to the principal point when there is no distortion)

However, the distortion due to tangential distortion is omitted in Equation (2).

In this case, (x _{n_d} , y _{n_d} ) are coordinates in the standard plane coordinates, and the actual image pixel coordinates (x _{p_d} , y _{p_d} ) reflect the camera internal parameters and are _{expressed as} Equation (3) and Equation (4) below. Become.

Equation (3)

Equation (4)

(Where f _x , f _y are focal lengths,

c _x and c _y are the lens center image coordinates)

Next, a corrected image is realized from the distorted image. A distorted image I _d, the corrected image I _u rahan. A point of the image I _u is called (x _pu , y _{p_u} ), and it is converted to (x _{n_u} , y _{n_u} ) from the standard plane coordinates by applying the camera parameter inversely. )

Equation (5)

Equation (6)

)를 구하고, 수학식(2)의 왜곡모델을 적용하여 왜곡된 좌표(x_{n_d}, y_{n_d})를 구한다.And the distance to the center r _u (

) And the distorted coordinates (x _{n_d} , y _{n_d} ) by applying the distortion model of Equation (2).

Equation (7)

Through the equation (7), the corrected coordinates (x _nu , y _{n_u} ) can be obtained from the distorted coordinates (x _nd , y _{n_d} ).

As described above, since the external light and the reflected light by the object appear together in the corrected image, it is necessary to distinguish and recognize the position of the external light (sunlight). In order to distinguish the external light from the reflected light, there must be a difference between the recognition sensitivity of the external light and the sensitivity recognized by the reflected light. When the sensitivity of the light tracking camera is high, it is difficult to accurately recognize the external light source. Therefore, the sensitivity must be minimized to clearly distinguish the reflected light reflected by the external light source and other objects.

If the sensitivity of the light tracking camera is low, there is a problem that the recognition of the brightness of the external light source is inferior because the sensitivity of the light tracking is narrow. In order to solve this problem, the present invention may be provided with a separate illumination sensor that can accurately measure the brightness around the display panel 100 to adjust the brightness of the display board using the data value of the illumination sensor.

As described above, the position of the external light source is accurately tracked through the light tracking camera, and the sharpness of the screen of the electronic sign 100 is adjusted according to the position of the external light source, and the brightness of the electronic sign is measured by measuring the brightness of the external light source more accurately through the illumination sensor. It can be adjusted to best suit the external environment.

The controller 300 receives light source information from the light tracking sensor 200 and generates image data displayed on the electronic display panel 100. The control unit 300 is composed of a control PC 310, a graphics card (not shown) and the analysis controller 320.

The control PC 310 generates image data displayed on the electronic sign 100 and transmits the image data to the display controller 400.

The graphics card may be provided inside the control PC 310 or may be configured separately from the control PC 310 and connected to the control PC 310. The graphics card may adjust the contrast or gamma value of the image data.

The analysis controller 320 receives the light source information from the light tracking sensor 200 and generates image correction data for adjusting the contrast or gamma value of the image. The image correction data is transmitted to the control PC 310 and the image data is corrected at the control PC 310 or the image data and the image correction data are transmitted to the display controller 400 through the control PC 310 to display the display controller ( Image data may be corrected at 400.

According to various embodiments of the present disclosure, as shown in FIG. 4, the analysis controller 320 may be excluded from the configuration of the controller 300.

The display controller 400 includes a main controller 410 and a subcontroller 420. The main controller 410 receives image data from the control PC 310 and converts the image data into a data format for display on the electronic display panel 100. The sub-controller 420 drives the plurality of LED modules 100 to display an image on the display panel 100. As described above, the main controller 410 may receive the image data and the image correction data from the control PC 310 to adjust the contrast and the gamma value of the image data. In addition, the main controller 410 may increase the number of colors of the image by amplifying the image data transmitted from the control PC (310).

The controller 300 or the display controller 400 as described above compares and analyzes the brightness of the light source information acquired by the light tracking sensor 200 and the brightness around the display panel 100 measured by the illuminance sensor. Adjust the contrast and gamma value of the image displayed in.

Contrast and gamma value adjustment of the image data may be performed by any one of the graphics card and the main controller 410 included in the control PC 310 or the main image after the primary image is adjusted by the control PC 310. The controller 410 may adjust the secondary image.

Since the optimum contrast and gamma value of the image that needs to be adjusted according to the light reflection of the screen 100 depends on the individual's preference or the characteristics of the image displayed on the screen 100, the setting of the adjustment value may be changed according to the situation. Can be.

Contrast

Contrast adjustment is achieved through the adjustment of the maximum brightness that can be expressed. (The method of increasing the sharpness by reducing the number of expression colors while maintaining the maximum brightness that can be expressed is through gamma adjustment.)

Lowering the contrast reduces sharpness and increasing it makes bright color subdivision difficult.

Unlike the display board, the dynamic contrast ratio used in TVs is not related to the display board by turning off the backlight of the black-representing part in the TV which uses the backlight.

The fixed-contrast ratio, which is often used in the description of TV sets, refers to the ratio of the brightness of the full black state and the white display state.

However, this is different from the electronic display board because it does not calculate the external illuminance. In the case of the electronic display board, since the expression of black is completely off, there is an infinite fixed brightness ratio.

gamma

Since a display device for displaying an image is a device for recognizing with the naked eye rather than a machine, it is necessary to transform the display device to a brightness level based on the human eye, not an accurate brightness level that is actually displayed (or measured by a machine).

Since the brightness level felt by the human eye is not proportional to the mechanical brightness level, a better image can be seen when the brightness level is modified by the gamma curve.

In other words, the human eye, which is sensitive to the increase in the brightness in the low brightness state, is insensitive to the increase in the brightness level in the brightness level in the high brightness state, and thus decreases the increase in the brightness level in the low brightness state and increases the brightness in the high brightness state. When the width is widened, the human eye perceives it as a regular brightness increase state, so that the best image is recognized.

Converting these brightness characteristics by a certain formula and creating new brightness levels through them is called gamma conversion.

In general, an apparatus for displaying an image of a TV, a beam projector, and the like enables improved visibility through gamma correction, and an electronic sign is also controlled to enable better image display through such gamma correction.

Increasing the gamma value reduces the number of displayed colors, but increases the sharpness of the image quality.

The sign board and the sign board system which can improve the image quality and visibility according to the present invention can be implemented in various modifications within the range that the technical idea of the present invention is not limited to the above-described embodiment.

100: electronic board,
101: electronic board body,
110, 110a, 110b, 110c: LED module,
111: LED,
112: shaded shade,
113: grill cover,
120: bezel,
200: light tracking sensor,
300: control unit,
310: control PC,
320: analysis controller,
400: display controller,
410: main controller,
420: subcontroller,
510: image pickup device,
520: lens,
AV: View angle,
FL: Focal length,
P: focal plane,

Claims (8)

In the electronic display board installed outdoors,
A light tracking sensor for tracking the position of the sunlight by distinguishing it from the reflected light by sunlight;
An electroluminescent plate body including a plurality of LED modules and a bezel surrounding the plurality of LED modules, and displaying an image in which a gamma value is adjusted according to a position of sunlight detected by the light tracking sensor; And
It is installed on the light plate main body includes an illuminance sensor for measuring the ambient brightness of the light plate main body,
The light tracking sensor is a light tracking camera that tracks the position of sunlight and measures the brightness of light incident from the sunlight,
The electronic sign main body compares the brightness of the light measured by the light tracking camera with the brightness of the light measured by the illuminance sensor and displays an image whose gamma value is adjusted according to the brightness of the corrected light. Sign board to improve the. delete delete In the signboard system for improving the visibility and image quality of the signboard installed outdoors,
An electronic board having an LED module for displaying an image;
A light tracking sensor for tracking the position of the sunlight by distinguishing it from the reflected light by sunlight and measuring the brightness of light incident from the sunlight;
An illuminance sensor for measuring the brightness around the display board;
A control unit receiving light source information from the light tracking sensor and generating image data displayed on the electronic display board; And
A display controller which receives the image data from the control unit, converts the image data into a data format for display on the electronic display board, and drives the LED module;
The controller or display controller corrects the brightness of the light by comparing the brightness of the light measured by the light tracking sensor with the brightness of the light measured by the illuminance sensor, and obtains information of the light source acquired by the light tracking sensor. Signboard system for improving the visibility and image quality, characterized in that for adjusting the contrast and gamma value of the image displayed on the signboard. The method according to claim 4,
The control unit,
An analysis controller which receives image information from the light tracking sensor and generates image correction data for adjusting the contrast or gamma value of the image;
Display board system for improving the visibility and image quality, characterized in that it comprises a control PC receives the image correction data from the analysis controller. The method according to claim 4,
The control unit,
A control PC for generating image data displayed on the display board;
And a graphic card provided in the control PC or connected to the control PC to adjust the contrast or the gamma value of the image data. delete The method according to claim 4,
The optical tracking sensor generates a corrected image from the distorted image,
A display system for improving visibility and image quality, wherein the distorted coordinates (x _{n_d} , y _{n_d} ) and corrected coordinates (x _{n_u} , y _{n_u} ) on the standard plane coordinates satisfy the following equation:

Here, k ₁ , k ₂ , k ₃ are radial distortion coefficient, r _u is the distance (radius) to the center (principal point) when there is no distortion.

Images