WO2014021490A1

WO2014021490A1 - Screen perception test device and screen perception test system using same

Info

Publication number: WO2014021490A1
Application number: PCT/KR2012/006289
Authority: WO
Inventors: 배기혁; 김현태; 조인제
Original assignee: 주식회사 씨케이앤비
Priority date: 2012-07-31
Filing date: 2012-08-08
Publication date: 2014-02-06
Also published as: KR101349153B1

Abstract

Disclosed are a screen perception test device and a screen perception test system using same. The screen perception test system according to one embodiment of the present invention comprises: a test image display device for displaying, on a screen, the test image in which a synchronization pattern is inserted to an original image; and a screen perception test device for repeatedly photographing the test image displayed on the test image display device while changing external illumination of the test image display device and/or a brightness level of the test image display device, and measuring the degree of screen perception compared with the original image for each image obtained by photographing.

Description

Screen recognition test device and screen recognition test system using the same

An embodiment of the present invention relates to a screen recognition test apparatus and a screen recognition test system using the same.

In electronic devices including displays (e.g., LCDs, LEDs, PDPs, smartphones, mobile phones, laptops, PCs, PDAs, digital cameras, camcorders, etc.), when a screen is displayed on the display, the user's screen perception It is affected by external illumination (eg, lighting or sunlight). Here, increasing the brightness level of the display to increase the screen recognition of the user increases the battery consumption of the electronic device, and lowering the brightness level of the display reduces the user's screen recognition.

Accordingly, in order to secure user's screen recognition while minimizing power consumption of the display, a technology for checking an optimal display brightness level according to external illumination has been proposed. In the conventional inspection technology, the illuminance of the lighting device is fixed at a predetermined level in a test room where the lighting device is installed, the screen recognition is measured while checking the screen recognition with the operator's eyes while varying the brightness level of the display. The lowest brightness level above the set threshold was determined by the brightness of the display at that illuminance. However, the prior art has a problem that the objectivity is lowered because the screen recognition is confirmed by the operator's eyes, thereby reducing the reliability.

An embodiment of the present invention is to provide a screen recognition test apparatus and a screen recognition test system using the same that can improve the objectivity and reliability of the data as a result of extracting the optimal brightness level according to the external illumination.

According to an aspect of the present invention, there is provided a screen recognition test system, including: a test image display apparatus displaying a test image in which a synchronization pattern is inserted into an original image on a screen; And repeatedly photographing the test image displayed on the test image display apparatus while changing at least one of an external illuminance of the test image display apparatus and a brightness level of the test image display apparatus, and recognizing a screen compared with an original image for each captured image. It includes a screen recognition test device for measuring the degree of sex.

In accordance with an aspect of the present invention, a screen recognition test apparatus includes: a photographing unit configured to photograph a test image displayed on a test image display apparatus; An illumination unit to change an external illuminance of the test image display device according to an illumination control signal; A synchronization pattern detector detecting the synchronization pattern in the captured image photographed by the photographing unit; An image restoring unit restoring the photographed image so that the photographed image has the size and coordinates of the original image by using the synchronization pattern; A screen recognition measurer for comparing the reconstructed photographed image with the original image to measure a degree of screen recognition of the photographed image compared to the original image; And the illumination unit, the photographing unit, and the test image to repeatedly photograph the test image displayed on the test image display device while changing at least one of an external illuminance of the test image display device and a brightness level of the test image display device. It includes a control unit for controlling the display device.

According to the embodiment of the present invention, the entire process of extracting the optimum brightness level of the display device according to the external illumination may be automated, thereby improving objectivity and reliability of the result data. In addition, it is possible to extract an optimal brightness level for securing screen recognition while minimizing power consumption of the display device for each external illuminance.

1 is a view showing the configuration of a screen recognition test system according to an embodiment of the present invention.

2 illustrates a first synchronization pattern and a second synchronization pattern according to an embodiment of the present invention.

3 is a diagram illustrating a test image in which an original image and a synchronization pattern are inserted according to an embodiment of the present invention.

4 is a diagram illustrating a configuration of an image level determining apparatus according to an embodiment of the present invention.

5 is a diagram illustrating a state in which a test image is displayed on a screen in a test image display device according to an embodiment of the present invention.

Hereinafter, an embodiment of a screen recognition test apparatus and a screen recognition test system using the same will be described with reference to FIGS. 1 to 5. However, this is only an exemplary embodiment and the present invention is not limited thereto.

In describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification.

The technical spirit of the present invention is determined by the claims, and the following embodiments are merely means for effectively explaining the technical spirit of the present invention to those skilled in the art to which the present invention pertains.

1 is a diagram showing the configuration of a screen recognition test system according to an embodiment of the present invention.

Referring to FIG. 1, the screen recognition test system 100 includes a test image generating device 102, an image level determining device 104, a test image display device 106, and a screen recognition test device 108. do. Here, some components of the test image display device 106 and the screen recognition test device 108 (that is, the photographing unit 131 and the lighting unit 132) may be installed in separate test rooms.

When the test image generating apparatus 102 receives the original image, the test image generating device 102 inserts a synchronization pattern into the received original image to generate the test image. The reason why the test image is generated by inserting the synchronization pattern into the original image is that when the test image is captured by the screen recognition test apparatus 108, the synchronization pattern is extracted from the captured image and the captured image is the same as the original image. To restore the size and coordinates.

The test image generating apparatus 102 may generate two synchronization patterns having different patterns, and then insert the generated synchronization patterns into a predetermined region of the original image to generate a test image. For example, the test image generating apparatus 102 generates three first synchronization patterns and one second synchronization pattern, and then generates three first synchronization patterns and one second synchronization pattern, respectively, at each corner of the original image. Insert it into the part to create a test image.

2 is a diagram illustrating a first synchronization pattern and a second synchronization pattern according to an embodiment of the present invention.

Referring to FIG. 2A, the first synchronization pattern 150 may include a first-first black pattern 151, a first white pattern 154 formed inside the first-first black pattern 151, and The first white pattern 154 includes a 1-2 black pattern 157 formed inside. The first-first black pattern 151, the first white pattern 154, and the first-second black pattern 157 may be formed in a square shape. However, the present invention is not limited thereto, and the first-first black pattern 151, the first white pattern 154, and the first-second black pattern 157 may be formed in a circular shape.

Here, the lengths of one side of the 1-1st black pattern 151, the first white pattern 154, and the 1-2th black pattern 157 may be, for example, in a ratio of 7: 5: 3. have. In this case, when the first synchronization pattern 150 is traversed in the vertical direction or the horizontal direction, the ratio at which the black pattern and the white pattern appear is 1 (black): 1 (white): 3 (black): 1 (white) It becomes: 1 (black).

Referring to FIG. 2B, the second synchronization pattern 160 includes a second-1 black pattern 161, a second white pattern 164 formed inside the second-1 black pattern 161, and And a second-2 black pattern 167 formed inside the second white pattern 164. The 2-1 black pattern 161, the second white pattern 164, and the 2-2 black pattern 167 may be formed in a square. However, the present invention is not limited thereto, and the 2-1 black pattern 161, the second white pattern 164, and the 2-2 black pattern 167 may be formed in a circular shape.

Here, the length of one side of the 2-1 black pattern 161, the second white pattern 164, and the 2-2 black pattern 167 may be, for example, a ratio of 5: 3: 1. have. In this case, when the second synchronization pattern 160 is traversed in the vertical direction or the horizontal direction, the ratio at which the black pattern and the white pattern appear is 1 (black): 1 (white): 1 (black): 1 (white) It becomes: 1 (black).

As such, the test image generating apparatus 102 forms the first synchronization pattern 150 and the second synchronization pattern 160 so that the black pattern and the white pattern are alternately displayed, thereby inserting the synchronization pattern in the test image. The maximum contrast difference may be generated, and thus, the screen recognition test apparatus 108 may easily detect the first synchronization pattern 150 and the second synchronization pattern 160.

FIG. 3 (a) shows the original image, and FIG. 3 (b) shows the test image generated by inserting the first synchronization pattern 150 and the second synchronization pattern 160 in each corner of the original image. It is shown.

The test image generating apparatus 102 transmits the test image in which the synchronization pattern is inserted to the test image display device 106 installed in the test room. In this case, the test image generating apparatus 102 may transmit the test image wirelessly or by wire.

The image level determining apparatus 104 determines the image level of the input original image. Here, the image level is an image characteristic of the original image itself (that is, the brightness of the original image and the complexity of the original image) that affects the degree of screen recognition when the screen recognition test apparatus 108 performs the screen recognition test. It is expressed numerically.

Referring to FIG. 4, the image level determining apparatus 104 includes an image brightness extracting unit 111, an image complexity measuring unit 114, and an image level determining unit 117.

The image brightness extracting unit 111 extracts a brightness component from the input original image. For example, the image brightness extracting unit 111 may convert the color space of the input original image into the YUV color space, and then extract only the Y component (that is, the luminance component) from the YUV color space.

The image complexity measuring unit 114 measures the complexity of the image with respect to the brightness component of the extracted original image. For example, the image complexity measuring unit 114 may apply the N × N size image complexity filter to the brightness component of the original image to measure the complexity of the image. In this case, as the image complexity filter, for example, an edge detection filter or a noise removing filter may be used.

The image level determiner 117 digitizes the image characteristics of the original image through the brightness of the original image and the complexity of the original image, and determines the image level of the original image according to the quantized image characteristic values. In this case, the brightness degree of the original image may be measured through the brightness component of the original image. The image level determiner 117 may obtain an image characteristic value of the original image by Equation 1 below.

Equation 1

Here, [Mean (I)] ^a represents the brightness of the original image normalized to a value between 0 and 1, and [Complex (I)] ^b represents the degree of complexity of the original image normalized to a value between 0 and 1. Indicates. In addition, a represents a weight for the degree of brightness of the original image, b represents a weight for the degree of complexity of the original image. Here, 0 ≦ a and b ≦ 1.

The image level determiner 117 may determine an image level by dividing the image characteristic values between 0 and 1 nonlinearly. Table 1 is a table showing the image level according to the image characteristic value.

Table 1

Image characteristic value	Image level
0 to 0.5	One
0.5 to 0.8	2
0.8 to 0.9	3
0.9 to 0.96	4
0.96-1.0	5

Referring to Table 1, the image level determiner 117 divides the image characteristic values into five nonlinear sections, for example, 0 to 0.5, 0.5 to 0.8, 0.8 to 0.9, 0.9 to 0.96, and 0.96 to 1.0. Thereafter, an image level may be provided for each section. Here, the lower the image characteristic value, the simpler the original image, and the higher the image characteristic value, the more complicated the original image. For example, if the original image is a simple image such as a notepad with letters, the image characteristic value of the original image is low. On the other hand, if the original image is a complex image containing many people and buildings, the image characteristic value of the original image is high.

The image level determiner 117 determines the image level of the corresponding original image according to the image characteristic value obtained by Equation 1 below. Here, the image characteristic values are divided into 5 sections, but the present invention is not limited thereto, and the image characteristic values may be divided into various other numbers.

The image level determining apparatus 104 transmits the image level of the original image to the screen recognition checking apparatus 108. In this case, the image level determining apparatus 104 may transmit the image level of the original image by wireless or by wire.

Although the test image generating device 102 and the image level determining device 104 are illustrated as separate devices, the test image generating device 102 and the image level determining device 104 may be integrated into a single device. It may be.

The test image display device 106 is installed in the test room and displays the test image received from the test image generating device 102 on the screen. In this case, the test image display device 106 may display the test image on the screen under the control of the controller 138. In this case, as illustrated in FIG. 5, a test image in which a synchronization pattern is inserted into each corner of the original image is displayed on the screen of the test image display device 106. In addition, the test image display device 106 changes the brightness level of the screen according to the input brightness control signal while displaying the test image on the screen.

Here, the test image display device 106 is a device to be tested, and an electronic device including a display is used. For example, the test image display device 106 may be an LCD, an LED, a PDP, a smartphone, a mobile phone, a notebook computer, a PC, a PDA, a digital camera, a camcorder, or the like, but is not limited thereto. Any electronic device can be used.

The screen recognition test apparatus 108 captures a test image displayed on the test image display device 106 while changing the brightness level of the test image display device 106 while maintaining the illuminance in the test room at a constant level. For each captured image, the degree of screen recognition of the captured image is measured compared to the original image. In this case, the screen recognition test apparatus 108 may set the lowest brightness level that exceeds the preset threshold value of the screen recognition degree of the captured image compared to the original image as the optimal brightness level of the test image display apparatus 106 for the corresponding illumination. Decide In addition, the screen recognition test apparatus 108 determines the optimal brightness level of the test image display apparatus 106 for each illuminance by repeating the above-described process while changing the illuminance in the test room to another level. .

The screen recognition test apparatus 108 may include a photographing unit 131, an illumination unit 132, a synchronization pattern detection unit 133, an image restoration unit 134, a screen recognition measurement unit 135, and a brightness level determination unit 136. , A storage unit 137, and a control unit 138.

The photographing unit 131 is installed in the test room and photographs the test image displayed on the test image display device 106 according to the photographing control signal of the controller 138.

The lighting unit 132 is installed in the test room and changes the illuminance level according to the lighting control signal of the controller 138. Here, the lighting unit 132 corresponds to external illumination when viewed from the perspective of the test image display device 106.

The synchronization pattern detector 133 detects a synchronization pattern from an image captured by the photographing unit 131 (hereinafter, referred to as a captured image). For example, the synchronization pattern detector 133 detects the three first synchronization patterns 150 in the captured image, and then measures the position of each of the first synchronization patterns 150 and the mutual distance between the first synchronization patterns 150. One second synchronization pattern 160 may be detected by checking.

The process of detecting the synchronization pattern from the captured image by the synchronization pattern detector 133 will now be described in detail.

1) The synchronization pattern detector 133 binarizes the captured image. In this case, the synchronization pattern detector 133 may binarize the captured image through Equation 2 below.

Equation 2

Where Img _B (i, j) represents a binarized image, Img _C (i, j) represents a captured image, M represents a local region of the captured image, and MAX represents two input variables

In comparison, the function that binarizes to 1 if the input variable on the left is larger than the value of the input variable on the right and 0 is smaller.

2) The synchronization pattern detector 133 detects three first synchronization patterns 150 from the binarized photographed image.

Specifically, 2-1) the synchronization pattern detection unit 133 scans the binarized photographed image in the horizontal direction so that the black pattern and the white pattern are 1 (black): 1 (white): 3 (black): 1 (white): The area represented by the ratio of 1 (black) (this is the ratio of the black pattern and the white pattern appearing when crossing the first synchronization pattern 150 in the horizontal direction as described above) is defined as the first synchronization pattern 150. We choose as candidate place.

2-2) The synchronization pattern detector 133 checks the number of the first candidate sheets and detects three first synchronization patterns 150 from the first candidate sheet, respectively, when there are three first candidate sheets. As a result of the check, when there are more than three first candidate papers, the synchronization pattern detector 133 scans the first candidate papers vertically among the first candidate papers so that the black pattern and the white pattern are 1 (black): 1 (white). The ratio of: 3 (black): 1 (white): 1 (black) (this is the ratio of the black pattern and the white pattern that appears when crossing the first synchronization pattern 150 in the vertical direction, as described above). The region is selected as the second candidate region of the first synchronization pattern 150.

2-3) The synchronization pattern detection unit 133 checks the number of second candidate papers and detects three first synchronization patterns 150 from the second candidate paper, respectively, when there are three second candidate papers. As a result of the check, when there are more than three second candidate sites, the synchronization pattern detection unit 133 measures distances between the second candidate sites and determines that three second candidate sites coincide with the distances between the first synchronization patterns 150. Each of the first synchronization patterns 150 is detected.

3) The synchronization pattern detector 133 checks the positions of the three detected first synchronization patterns 150 and then, through the distance information between the three first synchronization patterns 150 and the second synchronization pattern 160, 2 Select an area where the synchronization pattern 160 is assumed to be present. Then, the second synchronization pattern 160 is scanned at a position where the black pattern and the white pattern appear in a ratio of 1 (black): 1 (white): 1 (black): 1 (white): 1 (black) by scanning the selected area. Is detected.

The image restoring unit 134 restores the photographed image using the synchronization pattern detected from the photographed image so that the photographed image has the same size and coordinates as the original image. That is, when the photographing unit 131 captures the test image displayed on the test image display device 106, twisting and rotation may occur in the photographed image according to the photographing angle and the photographing distance of the camera, and may be different from the size of the original image. It can be sized. Therefore, the image restoring unit 134 restores the captured image so that the captured image has the same size and coordinates as the original image using the detected synchronization pattern.

For example, the image reconstructor 134 may include location information (ie, distance and angle information between the synchronization patterns) of the three first synchronization patterns 150 and the one second synchronization pattern 160 detected from the captured image. By correcting the torsion, size conversion, rotation, etc. of the captured image using a 3D Project Matrix, which is inputted as), the captured image can be restored so that the captured image has the same size and coordinates as the original image.

The screen recognition measurer 135 compares the captured image and the original image to measure the degree of screen recognition of the captured image compared to the original image. In this case, the screen recognition measurer 135 captures the image compared with the original image according to the difference between the average brightness between the captured image and the original image, the difference between the average dispersion value between the captured image and the original image, and the dispersion value between the captured image and the original image The degree of screen recognition of an image may be measured. For example, the screen recognition measurer 135 may measure the degree of screen recognition (PIQ) of the captured image compared to the original image by Equation 3 below.

Equation 3

Here, I represents an original image, and I 'represents a photographed image. B (I, I ') represents the difference in average brightness between the original image and the captured image, and C (I, I') represents the difference in the average variance value between the original image and the captured image, and PQ (I, I '). ) Represents a correlation between the variance values between the original image and the captured image. Also, α represents a weight for the difference in average brightness between the original image and the captured image, β represents a weight for the difference in the mean variance value between the original image and the captured image, and δ represents a correlation of the variance value between the original image and the captured image The weights for the figures are shown. At this time, 0 ≦ α, β, δ ≦ 1.

B (I, I '), which is the average brightness difference between the original image and the captured image, can be obtained by the following equation (4).

Equation 4

Here, μ _I represents the average brightness of the original image, and μ _{I '} represents the average brightness of the captured image.

C (I, I '), which is the difference between the mean variance values between the original image and the captured image, can be obtained by the following equation (5). In this case, the difference in the mean variance value between the original image and the captured image means the difference in image complexity between the original image and the captured image.

Equation 5

Here, sigma _I represents an average variance value of the original image, and sigma _{I '} represents an average variance value of the captured image.

PQ (I, I '), which is a correlation between the variance values between the original image and the captured image, can be obtained by the following equation. In this case, the correlation between the dispersion values between the original image and the captured image means the similarity between the original image and the captured image.

Equation 6

Here, sigma _{II '} represents a variance value of the difference image between the original image and the captured image.

Meanwhile, in Equation 3, each weight (α, β, δ) value may be determined by the image level of the original image. Table 2 is a table showing the weight (α, β, δ) value according to the image level of the original image. However, this is only one embodiment, and each weight value is not limited thereto.

TABLE 2

Image level (image property value)	α	β	δ
1 (0 to 0.5)	One	One	0
2 (0.5 to 0.8)	0.5	0.3	0.2
3 (0.8 to 0.9)	0.3	0.2	0.5
4 (0.9 to 0.96)	0.1	0.2	0.7
5 (0.96-1.0)	0	0.1	0.9

Referring to Table 2, when the image level is 1, for example, the original image is a text image written on a white background, and the brightness component of the image and the complexity of the image have a great influence on screen recognition and the original image. The similarity between the captured image and the captured image does not affect the screen recognition. Therefore, when the image level is 1, the weight values of the weights α and β are each 1, and the weight value of the weights δ is 0.

For example, when the image level is 5, for example, the original image is a photographic image showing a lot of people and buildings, and the brightness component of the image of the image and the complexity of the image have little effect on the screen perception. The similarity between the photographed image and the image has a great influence on the screen recognition. Therefore, when the image level is 5, the weight values of the weights α and β are set to 0 and 0.1, respectively, and the weight values of the weight δ are set to 0.9.

In this way, by determining the weight (α, β, δ) value according to the image level, it is possible to accurately measure the degree of screen recognition of the captured image compared to the original image by reflecting the image characteristics of the original image.

The brightness level determiner 136 captures test images displayed on the test image display device 106 while changing the brightness level of the test image display device 106 while maintaining the illuminance in the test room at a constant level. When the screen recognition degree of the captured image compared to the original image is measured for each captured image, the test image for the corresponding illuminance shows the lowest brightness level at which the screen recognition degree of the captured image compared to the original image exceeds the preset threshold. The optimal brightness level of the display device 106 is determined. In this case, it is possible to determine an optimal brightness level that can secure screen recognition while minimizing power consumption.

For example, assuming that the threshold of the screen recognition degree of the captured image compared to the original image is 0.8, and the illuminance in the test room is fixed at 15 Lux, the brightness level of the test image display device 106 is set to 30. Let's change from 250 to 250 to measure the degree of screen recognition compared to the original video of each shot. At this time, when the brightness level of the test image display device 106 is 50 to 200, and the screen recognition degree of the captured image is greater than 0.8 compared to the original image, the brightness level determiner 136 is 15 lux. Determine the optimal brightness level at.

As another example, assuming that the threshold of the degree of screen recognition of the captured image compared to the original image is 0.8, the brightness of the test image display device 106 is fixed while the illuminance in the test room is fixed at 55 Lux. Let's change the level from 30 to 250, and measure the degree of screen recognition compared to the original image of each shot. At this time, when the brightness level of the test image display device 106 is 80 to 200, and the screen recognition degree of the captured image is greater than 0.8 when the brightness of the test image display device 106 is greater than the original image, the brightness level determiner 136 is 55 lux. Determine the optimal brightness level at 80.

The storage unit 137 stores the image level of the original image transmitted by the image level determining apparatus 104 under the control of the controller 138. The storage unit 137 stores each photographed image photographed by the photographing unit 131 under the control of the controller 138. In addition, the storage unit 137 stores the original image.

When the test image is transmitted from the test image generating device 102 to the test image display device 106, the controller 138 controls the test image display device 106 to display the test image on the screen. The controller 138 generates an illumination control signal to the illumination unit 132 to control the illumination level of the illumination unit 132. The controller 138 generates a photographing control signal to the photographing unit 131 to control the photographing unit 131 to photograph the test image displayed on the test image display device 106.

In detail, when the test image is displayed on the screen of the test image display device 106, the controller 138 changes the brightness level of the test image display device 106 while fixing the illuminance of the illumination unit 132 at a predetermined level. The photographing unit 131, the lighting unit 132, and the test image display device 106 are controlled to photograph the test image displayed on the screen of the test image display device 106. Next, the controller 138 changes the illuminance of the illumination unit 132 to another level, and then changes the brightness level of the test image display device 106 to photograph the test image while capturing the test image. ) And the test image display device 106, and this process is repeatedly performed while changing the illuminance level of the lighting unit 132.

For example, the controller 138 may change the brightness level of the test image display device 106 from 30 to 250 while the illumination level of the lighting unit 132 is fixed to 15 lux. You can take a test image displayed on the screen. Subsequently, the controller 138 changes the illuminance level of the lighting unit 132 to 30 lux, and then changes the brightness level of the test image display device 106 from 30 to 250, and then displays the screen of the test image display device 106. You can shoot the displayed test image. Thereafter, the controller 138 may repeatedly perform this process while changing the illuminance level of the lighting unit 132 to 55 lux, 150 lux, 600 lux, 1000 lux, or the like.

Although the present invention has been described in detail with reference to exemplary embodiments above, those skilled in the art to which the present invention pertains can make various modifications to the above-described embodiments without departing from the scope of the present invention. Will understand. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

[Description of the code]

100: screen recognition test system 102: test image generating device

104: image level determination device 106: test video display device

108: screen recognition test device 111: image brightness extraction unit

114: image complexity measurement unit 117: image level determination unit

131: photographing unit 132: lighting unit

133: synchronization pattern detection unit 134: image restoration unit

135: screen recognition unit 136: brightness level correction

137: storage unit 138: control unit

Claims

A test image display device displaying a test image in which a synchronization pattern is inserted into an original image on a screen; And

The test image displayed on the test image display device is repeatedly photographed while changing at least one of the external illuminance of the test image display device and the brightness level of the test image display device. A screen recognition test system comprising a screen recognition test device for measuring the degree.
The method of claim 1,

The screen recognition test system,

And an image level determination device for determining an image level of the original image and transmitting the image level to the screen recognition test device.
The method of claim 2,

The image level determination device,

And quantifying an image characteristic of the original image based on a degree of brightness of the original image and a degree of complexity of the original image, and determining an image level of the original image according to the digitized image characteristic value.
The method of claim 3,

The image level determination device,

A screen recognition test system for quantifying the image characteristics of the original image by the following equation.

(Mathematical formula)

Where [Mean (I)] a : brightness of the normalized original image.

[Complex (I)] b : degree of complexity of the normalized original image.

a: Weight for brightness level of original image.

b: weight for the degree of complexity of the original image.
The method of claim 1,

The screen recognition test device,

An illumination unit to change an external illuminance of the test image display device according to an illumination control signal;

A photographing unit which photographs a test image displayed on the test image display device;

A synchronization pattern detector detecting the synchronization pattern in the captured image photographed by the photographing unit;

An image restoring unit restoring the photographed image so that the photographed image has the size and coordinates of the original image by using the synchronization pattern; And

And a screen recognition measurer for comparing the restored photographed image with the original image to measure a degree of screen recognition of the photographed image compared to the original image.
The method of claim 5,

The screen recognition measurement unit,

The screen recognition test system for measuring the degree of screen recognition of the photographed image compared to the original image by the following equation.

(Mathematical formula)

Where I is the original image.

I ': Shooting video.

B (I, I '): Average brightness difference between the original image and the captured image.

C (I, I '): The difference in the mean variance between the original and captured images.

PQ (I, I '): Correlation between variance values between the original image and the captured image.

α: Weight for the average brightness difference between the original image and the captured image.

β: Weight for the difference in the mean variance between the original and captured images.

δ: Weight for the correlation between the variance values between the original image and the captured image.
The method of claim 6,

The weight α, β, δ is,

And a screen recognition test system determined by the image level of the original image.
The method of claim 5,

The screen recognition test device,

The display device may further include a brightness level determiner configured to determine, as an optimal brightness level of the test image display device for a corresponding external illuminance, the lowest brightness level at which the degree of screen recognition of the captured image compared to the original image exceeds a preset threshold. Cognitive Test System.
The method of claim 1,

The screen recognition test system,

And a test image generating device configured to generate the test image by inserting the synchronization pattern into the original image, and to transmit the generated test image to the test image display device.
The method of claim 9,

The test image generating device,

After generating three first synchronization patterns and one second synchronization pattern, the test images are generated by inserting the three first synchronization patterns and the one second synchronization pattern into four corner portions of the original image, respectively. Screen recognition test system.
A photographing unit which photographs a test image displayed on the test image display device;

An illumination unit to change an external illuminance of the test image display device according to an illumination control signal;

A synchronization pattern detector detecting the synchronization pattern in the captured image photographed by the photographing unit;

An image restoring unit restoring the photographed image so that the photographed image has the size and coordinates of the original image by using the synchronization pattern;

A screen recognition measurer for comparing the reconstructed photographed image with the original image to measure a degree of screen recognition of the photographed image compared to the original image; And

The lighting unit, the photographing unit, and the test image display to repeatedly take a test image displayed on the test image display device while changing at least one of an external illuminance of the test image display device and a brightness level of the test image display device. And a control unit for controlling the device.
The method of claim 11,

The screen recognition measurement unit,

The screen recognition test device for measuring the degree of screen recognition of the photographed image compared to the original image by the following equation.

(Mathematical formula)

Where I is the original image.

I ': Shooting video.

B (I, I '): Average brightness difference between the original image and the captured image.

C (I, I '): The difference in the mean variance between the original and captured images.

PQ (I, I '): Correlation between variance values between the original image and the captured image.

α: Weight for the average brightness difference between the original image and the captured image.

β: Weight for the difference in the mean variance between the original and captured images.

δ: Weight for the correlation between the variance values between the original image and the captured image.
The method of claim 12,

The weight α, β, δ is,

And a screen recognition test apparatus determined by the image level of the original image.
The method of claim 11,

The screen recognition test device,

The display device may further include a brightness level determiner configured to determine, as an optimal brightness level of the test image display device for a corresponding external illuminance, the lowest brightness level at which the degree of screen recognition of the captured image compared to the original image exceeds a preset threshold. Cognitive testing device.