CN217112049U - Screen color uniformity detection device - Google Patents

Abstract

The utility model relates to a screen inspection technical field, concretely relates to screen color homogeneity detection device, include: a camera for capturing an image; the analyzer is arranged on the camera and converts light rays passing through the analyzer into polarized light with a set angle; the angle adjuster is connected with the analyzer, and the analyzer is driven to rotate through the movement of the angle adjuster, so that the polarization angle of the analyzer is changed, and the camera can shoot images at different polarization angles; the controller is connected with the camera and used for controlling the shooting of images and analyzing and detecting the images shot by the camera, and the controller is also connected with the angle regulator and used for controlling the angle regulator to move. This application is shot at fixed position through controller control camera, carries out angle modulation through the angle modulation ware to the analyzer for the analyzer is in different polarization angle, and then makes the camera can shoot the image at the different polarization angle of fixed position.

Description

Screen color uniformity detection device

Technical Field

The utility model relates to a screen detection technology field particularly, relates to a screen color homogeneity detection device.

Background

The uniformity of the screen color (or brightness) means that the colors of all pixels are consistent when the screen displays the same color, the whole screen is divided into 9 blocks by national standard, and the brightness difference of the color between every two blocks is not more than 25%, namely the screen is qualified (see the following figure). The quality requirement in actual production generally requires a brightness difference of 10%, which substantially ensures the uniformity of the brightness color when observed by human eyes.

The traditional method adopts visual inspection, namely, the whole screen of the screen displays various colors such as black, pure white, red, green, blue and the like, and then people observe whether the difference exists, thereby judging the uniformity of the screen in various color states. The mode has larger visual power consumption, is easy to cause eye fatigue, and has problems in the detection precision and stability of the human eyes for the screen with higher quality requirement.

In view of the problem of human eye detection, some current screen detection adopts a machine vision method for detection, and is divided into two main methods.

The other method adopts a large-format CCD color camera to shoot the whole screen at one time and then analyze the color uniformity of each part of the whole picture. The mode is widely applied to the field of equivalent-size screens of mobile phones and small-size PADs, and good effect and benefit are obtained. But the mode of whole screen shooting for a large-size screen has poor effect. Mainly because the current screen emits polarized light, the brightness is different when the screen is observed at different angles; a telephoto lens is used to ensure that the angle at which the screen light is incident on the camera is close, which results in a sufficient distance of the camera from the screen.

One solution is to reduce the shooting visual field on the premise of adopting a long-focus lens, thereby greatly shortening the distance from the screen to shooting; meanwhile, the whole screen is detected by moving the camera for multiple times of shooting.

However, this method requires that the shooting status after each movement is consistent, i.e., the distance and angle to the screen are consistent, the noise of the camera is consistent, and the ambient light interference is consistent. The dark room is generally adopted to eliminate the ambient light interference on the actual production line, the accurate position of the screen is adopted, the camera is perpendicular to the screen, the camera motion is parallel to the plane of the screen, the distance and the angle between the camera and the screen are consistent, and the consistency of the noise is realized by adopting a low-noise CCD camera, a large-size CCD chip and an optimized circuit processing chip.

Therefore, it is difficult to achieve the above-described consistency of conditions.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a screen color uniformity detection device, and the polarization angle of an analyzer is adjusted, so that the camera can shoot images at different polarization angles of fixed positions.

According to an embodiment of the present application, there is provided a screen color uniformity detecting apparatus including:

a camera for capturing an image;

the analyzer is arranged on the camera and converts light rays passing through the analyzer into polarized light with a set angle;

the angle adjuster is connected with the analyzer, and the analyzer is driven to rotate through the movement of the angle adjuster, so that the polarization angle of the analyzer is changed, and the camera can shoot images at different polarization angles;

the controller is connected with the camera and used for controlling the shooting of images and analyzing and detecting the images shot by the camera, and the controller is also connected with the angle regulator and used for controlling the angle regulator to move.

Further, the analyzer includes a polarizing film disposed in a rotating gear, and a rotating gear engaged with a motor gear on the angle adjuster.

Further, the angle regulator also comprises a motor, the controller is connected with the motor and drives the motor to rotate, and a motor gear is arranged on the motor.

Further, detection device still includes the encoder, and the encoder setting detects motor pivoted angle at the motor, and the controller is connected with the encoder to acquire the angle that the encoder detected.

Furthermore, the detection device also comprises a lens, wherein the lens is positioned between the camera and the analyzer and is used for collecting the polarized light passing through the analyzer.

Further, the controller includes:

the diffusion film detection module is connected with the camera and used for detecting the backlight penetrating through the diffusion film and comparing the uniformity of the image backlight shot at different angles;

the polarization film detection module is connected with the camera and is used for detecting the backlight after penetrating through the diffusion film and the polarization film and comparing the uniformity of the image polarized light shot at different angles;

and the liquid crystal layer detection module is connected with the camera and is used for detecting the backlight penetrating through the diffusion film and the polarizing film and the liquid crystal layer and comparing the uniformity of the image polarized light shot at different angles.

Further, the controller further comprises:

and the computing module respectively computes whether the brightness uniformity of the polarized light passing through the polarizing film and the liquid crystal layer is consistent.

Furthermore, a warning module is arranged on the controller.

The screen color uniformity detection device in the embodiment of the application comprises: a camera for capturing an image; the analyzer is arranged on the camera and converts light rays passing through the analyzer into polarized light with a set angle; the angle adjuster is connected with the analyzer, and the analyzer is driven to rotate through the movement of the angle adjuster, so that the polarization angle of the analyzer is changed, and the camera can shoot images at different polarization angles; the controller is connected with the camera and used for controlling the shooting of images and analyzing and detecting the images shot by the camera, and the controller is also connected with the angle regulator and used for controlling the angle regulator to move. This application is shot at fixed position through controller control camera, carries out angle modulation to the analyzer through the angle modulation ware for the analyzer is in different polarization angle, and then makes the camera can shoot the image at the different polarization angle of fixed position, has avoided needing to remove the camera and has shot the image of different angles, and the environmental condition inconsistent problem of shooting the image that causes.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention and do not constitute a limitation on the invention. In the drawings:

FIG. 1 is a flow chart of the method for detecting uniformity of screen color of the present invention;

FIG. 2 is a schematic diagram of the device for detecting color uniformity of a screen according to the present invention;

FIG. 3 is a schematic diagram of the present invention for detecting backlight of a screen;

FIG. 4 is a diagram of a reference ellipse of the present invention;

fig. 5 is a schematic diagram of the terminal device of the present invention.

Reference numerals: the system comprises a camera 1, a lens 2, a polarization analyzer 3, a polarization film 301, a rotating gear 302, a motor 4, a motor gear 5, an encoder 6 and a controller 7.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Referring to fig. 2 and 3, according to an embodiment of the present application, there is provided a screen color uniformity detecting apparatus including:

a camera 1, the camera 1 being used to take images;

the analyzer 3, the analyzer 3 is set in camera 1, the analyzer 3 changes the light passing through the analyzer 3 into the polarized light of the set angle;

the angle adjuster is connected with the analyzer 3, and the analyzer 3 is driven to rotate through the movement of the angle adjuster, so that the polarization angle of the analyzer 3 is changed, and the camera 1 can shoot images at different polarization angles;

and the controller 7 is connected with the camera 1, controls to shoot images and analyzes and detects the images shot by the camera 1, and the controller 7 is also connected with the angle regulator and controls the angle regulator to move.

The screen color uniformity detection device in the embodiment of the application comprises: a camera 1, the camera 1 being used to take images; the analyzer 3, the analyzer 3 is set in camera 1, the analyzer 3 changes the light passing through the analyzer 3 into the polarized light of the set angle; the angle adjuster is connected with the analyzer 3, and the analyzer 3 is driven to rotate through the movement of the angle adjuster, so that the polarization angle of the analyzer 3 is changed, and the camera 1 can shoot images at different polarization angles; and the controller 7 is connected with the camera 1, controls to shoot images and analyzes and detects the images shot by the camera 1, and the controller 7 is also connected with the angle regulator and controls the angle regulator to move. This application is shot at fixed position through controller 7 control camera 1, carries out angle modulation to analyzer 3 through angle modulation ware for analyzer 3 is in different polarization angle, and then makes camera 1 can shoot the image at the different polarization angle of fixed position, has avoided needing to remove camera 1 and has shot the image of different angles, and the environmental condition inconsistent problem of shooting the image that causes.

Specifically, the controller 7 starts the motor 4, detects the angle information detected by the encoder 6, and after the polarizing film 301 reaches a set angle, the controller 7 controls to stop the rotation of the motor 4 so that the polarizing film 301 is at a specified angle; the controller 7 controls the camera 1 to perform image shooting to obtain a polarized image of the specified angle of the polarized film 301; the driving motor 4 is continuously and repeatedly driven to drive the polarization film 301 to reach a new set angle, and then the camera 1 is used for shooting, so that polarization images of a plurality of polarization angles can be obtained.

In the embodiment, the analyzer 3 includes a polarizing film 301 and a rotary gear 302, the polarizing film 301 is disposed in the rotary gear 302, and the rotary gear 302 is engaged with the motor gear 5 on the angle adjuster. The controller 7 controls the angle adjuster to move, drives the analyzer 3 meshed with the angle adjuster to rotate, and the analyzer 3 enables the camera 1 to shoot images with different polarization angles at fixed positions through rotation.

In the embodiment, the angle regulator further comprises a motor 4, the controller 7 is connected with the motor 4 and drives the motor 4 to rotate, and the motor gear 5 is arranged on the motor 4. The controller 7 controls the motor 4 to rotate, the motor gear 5 is arranged on the motor 4, and the motor gear 5 is meshed with the rotating gear 302, so that the controller 7 can drive the analyzer 3 to rotate by controlling the rotation of the motor 4.

In an embodiment, the detection device further comprises an encoder 6, the encoder 6 is arranged on the motor 4 and used for detecting the rotation angle of the motor 4, and the controller 7 is connected with the encoder 6 so as to obtain the angle detected by the encoder 6. An encoder 6 is provided on the motor 4, the encoder 6 is used to detect the angle of rotation of the motor 4 when the motor 4 rotates, so that the angle of rotation of the polarizing film 301 can be obtained, and the controller 7 obtains information of the angle of rotation detected by the encoder 6 by reading the encoder 6, and the controller 7 drives the motor 4 to rotate or stop rotating according to the obtained information of the angle.

In an embodiment, the detection apparatus further includes a lens 2, and the lens 2 is located between the camera 1 and the analyzer 3 and is used for collecting polarized light after passing through the analyzer 3. The light passes through the analyzer 3 and then is converted into polarized light, the lens 2 collects the polarized light, and the camera 1 shoots images through the lens 2.

In an embodiment, the controller 7 includes:

the diffusion film detection module is connected with the camera and used for detecting the backlight penetrating through the diffusion film and comparing the uniformity of the image backlight shot at different angles;

the polarization film detection module is connected with the camera and is used for detecting the backlight penetrating through the diffusion film and the polarization film and comparing the uniformity of the image polarized light shot at different angles;

and the liquid crystal layer detection module is connected with the camera and is used for detecting the backlight penetrating through the diffusion film and the polarizing film and the liquid crystal layer and comparing the uniformity of the image polarized light shot at different angles.

Specifically, a diffusion film is added in the backlight of the screen, and a diffusion film detection module passes through the backlight of the diffusion film; when the uniformity of the image backlight is detected to be qualified, the detection of the polarizing film 301 is carried out; when the backlight passing through the polarizing film 301 is detected to be qualified by the polarizing film detection module, detecting the liquid crystal layer; the polarizing film sensing module senses the backlight after passing through the liquid crystal layer.

Specifically, the present application uses the polarization camera 1 to capture the screen brightness at a plurality of polarization angles, and then calculates the polarization angle of incident light for each pixel in the captured image based on the brightness information, thereby evaluating the brightness uniformity thereof.

In the embodiment, the controller 7 is provided with an alarm module. The warning module is used for sending out warning that the screen is uneven in brightness if the screen backlight does not meet the second preset condition or the third preset condition.

The third detection is to detect the uniformity of the brightness of the screen, if the third preset condition is not met, the screen brightness is not uniform, and if the pixel can be judged to be a point with non-uniform brightness through the calculation of the method, the controller 7 gives a warning that the screen brightness is not uniform.

In an embodiment, the controller 7 further comprises:

and the computing module respectively computes whether the brightness uniformity of the polarized light passing through the polarizing film and the liquid crystal layer is consistent.

The present application judges whether the uniformity of polarized light is consistent by calculation in such a manner that whether a pixel is a non-uniform point is judged in the case where the phase difference is 0 degrees or 180 degrees and the phase difference is not 0 degrees or 180 degrees as in the following method embodiment; the specific calculation process is described in detail in the following method embodiments, and the detailed description is omitted here.

Currently, some screen inspection methods adopt a machine vision method for inspection, and are divided into two main methods:

the first is to detect the color uniformity at several locations on the screen using a chrominance camera, which detects chrominance and luminance information with considerable accuracy. But the requirement on the measurement condition is strict, the angle of shooting for each measurement needs to be vertical to the screen, and the distance from the probe to the screen is fixed and shorter (peripheral brightness interference is reduced). Therefore, the detection speed is relatively slow, and the detection range of each time is quite small, and the method is generally used for the production process management and control detection in the sampling inspection.

The second method adopts a large-format CCD color camera to shoot the whole screen at one time, and then analyzes the color uniformity of each part of the whole picture. The mode can be widely applied to the fields of mobile phones and small PAD equivalent size screens, and good effect and benefit are obtained.

But the mode of whole screen shooting for a large-size screen has poor effect. Mainly due to two factors;

the first factor is that the pixel number of the CCD chip is generally required to be more than the pixel number of the screen, so that the pixel level detection of the screen is realized; the number of pixels of a large screen is more, for example, the number of pixels of a 4K display screen is more than 400 ten thousand;

the second factor is that the current screen emits polarized light, and the brightness is different when the screen is observed at different angles; a telephoto lens 2 is used to ensure that the angle of incidence of the screen light into the camera 1 is close, which allows the camera 1 to be sufficiently distant from the screen.

One solution is to reduce the shooting visual field on the premise of adopting a long-focus lens, thereby greatly shortening the distance from the screen to shooting; meanwhile, the whole screen is detected by moving the camera 1 to shoot for multiple times. However, this method requires that the shooting status after each movement is consistent, that is, the distance and angle to the screen are consistent, the noise of the camera is consistent, and the interference of the ambient light is consistent. In reality, a darkroom is generally adopted on a production line to eliminate ambient light interference, the distance and the angle between the darkroom and the screen are consistent by combining the accurate position of the screen, the vertical direction of the camera 1 to the screen and the parallel direction of the motion of the camera 1 to the plane of the screen, and the consistency of noise is realized by adopting a low-noise CCD camera 1, a large-size CCD chip and an optimized circuit processing chip. It is difficult to achieve the required consistency.

Another idea is that the screen areas shot by the camera each time are overlapped, and the reference brightness between the pictures is adjusted by using the characteristic that the brightness of the overlapped area is unchanged in a short time, which needs to consider a reference interference elimination mechanism under the condition that the brightness of the overlapped area is not uniform, and a uniform comparison algorithm of uniform references between multiple pictures needs to be solved, and these problems make the related reference calculation method quite complex.

The method requires that the brightness of the backlight source (after the diffusion film is added) is uniform, and the polarization angle of the backlight source after the polarization film is added is uniform. Therefore, the three-level detection mode is adopted in the application.

Referring to fig. 3, the following describes the screen color uniformity detection apparatus in detail by using a specific embodiment:

and (3) first-stage detection: the backlight after the diffusion film is added is detected, and the backlight after the diffusion film is added is unpolarized light with isotropy and uniform brightness and has no pixel resolution requirement. Therefore, the CCD camera 1 is adopted to vertically shoot the whole screen, and whether the corresponding backlight source meets the requirement or not can be detected; in order to increase the detection granularity, the camera 1 can be slightly translated on the screen plane for multiple times to shoot, and the uniformity of each picture is compared, so that the increase of the detection granularity can be realized; and releasing the qualified product meeting the requirements to the next process.

And (3) second-stage detection: adding a polarizing film for backlight detection, wherein the qualified (diffusion film added) backlight brightness is consistent, and the emergent light brightness is consistent as long as the polarizing direction of the polarizing film is consistent; therefore, the polarization direction detection method can be used for detecting whether the polarization directions are consistent, and if the polarization directions are consistent, the next procedure can be carried out for the third-stage detection.

And (3) third-stage detection: mainly detecting the uniformity of the screen; in the two detections, the backlight sources with consistent brightness except for consistent polarization direction are screened; therefore, the screen brightness is completely determined by the polarization angle, and the detection of the polarization angle in the third and the detection can realize the detection of the uniformity of the screen brightness.

The three-level detection scheme can realize accurate detection and control of each link of backlight processing, and finally realize detection of screen brightness. Meanwhile, the brightness of a plurality of pictures shot in multiple regions can be adjusted as a reference based on the calculation of the polarization direction of light rays emitted by the screen, so that the basis for the multi-picture fusion of the next detection of the screen based on multiple times of shooting is provided.

Referring to fig. 1, according to an embodiment of the present application, there is provided a method for detecting screen color uniformity, including the following steps:

s101: acquiring a plurality of pictures shot for a screen under a plurality of polarization angles, wherein the plurality of pictures are obtained by shooting the screen with backlight for a plurality of times at fixed positions;

s102: based on a plurality of pictures correspondingly acquired under a plurality of polarization angles, taking a gray value of a corresponding pixel for each picture;

s103: calculating and acquiring the phase difference of the polarization angle of each picture based on the acquired gray values;

s104: and judging whether the polarized light of each picture is linearly polarized light or circularly polarized light based on the phase difference, and calculating whether the corresponding pixel of the picture is a point with uniform brightness according to the linearly polarized light or the circularly polarized light.

The method and the device for detecting the uniformity of the screen color in the embodiment of the application comprise the following steps: acquiring a plurality of pictures shot on a screen at a plurality of angles, wherein the plurality of pictures are obtained by shooting the screen with backlight for a plurality of times at a fixed position; based on a plurality of pictures correspondingly acquired under a plurality of polarization angles, taking a gray value of a corresponding pixel for each picture; calculating and acquiring the phase difference of the polarization angle of each picture based on the acquired gray values; and judging whether the polarized light of each picture is linearly polarized light or circularly polarized light based on the phase difference, and calculating whether the corresponding pixel of the picture is a point with uniform brightness according to the linearly polarized light or the circularly polarized light. According to the method and the device, the picture is obtained through fixed shooting, the requirement for consistency of conditions due to the fact that multiple times of moving shooting are needed for screen detection is avoided, and the problem of brightness difference of polarized light caused by multiple observation angles in screen detection is solved.

Referring to fig. 1 and 4, based on the phase difference, it is determined whether the polarized light of each picture is linearly polarized light or circularly polarized light, and according to the linearly polarized light or the circularly polarized light, it is specifically calculated whether the corresponding pixel of the picture is a point where the brightness is uniform:

when the phase difference is 0 degree or 180 degrees, the polarized light of the picture is linearly polarized light, and whether the corresponding pixel of the picture is a point with uniform brightness is calculated according to the linearly polarized light;

when the phase difference is not 0 degree or 180 degrees, the polarized light of the picture is circularly polarized light, and whether the corresponding pixel of the picture is a point with uniform brightness or not is calculated according to the circularly polarized light.

The following specific steps are that when the phase difference is 0 degree or 180 degrees, the polarized light is linearly polarized light, and whether the corresponding pixel of the picture is a point with uniform brightness is calculated:

the method comprises the following steps: when the phase difference is 0 degree or 180 degrees, the polarized light is linearly polarized light, and the polarization azimuth angle of the linearly polarized light of each pixel is calculated;

step two: removing the maximum value and the minimum value in the plurality of polarization azimuth angles, and calculating the average value of the residual polarization azimuth angles;

step three: when it is satisfied with

If so, judging the pixel as a point with uneven brightness; wherein the content of the first and second substances,

the average value of a plurality of polarization azimuth angles is shown, theta represents any one polarization azimuth angle, and sigma is a set threshold value.

The method is directly oriented to the screen display polarization principle, and the traditional screen uniformity detection method depending on brightness is replaced by the characteristic based on polarized light. A polarization detector is arranged in the camera, and a plurality of pictures at different angles of the polarization detector are shot under the condition that the polarization camera is fixed and is vertical to a screen; calculating the phase difference of polarized light when the picture is shot through a phase difference formula, wherein when the phase difference is 0 degree or 180 degrees, the polarized light is linearly polarized light, and after the linear polarization azimuth angle of each picture pixel is calculated, a truncation average value is obtained

(i.e., calculating the mean value after deleting some maximum values and minimum values according to the proportion), and setting a threshold value sigma; for the

The pixel of (2) is determined as a point of uneven brightness.

The following specific steps are that when the phase difference is not 0 degree or 180 degrees, the polarized light is circularly polarized light, and whether the corresponding pixel of the picture is a point with uniform brightness is calculated:

the method comprises the following steps: when the phase difference is not 0 degree or 180 degrees, the polarized light is circularly polarized light, and the elliptical area corresponding to each pixel and the major axis, the minor axis and the rotation angle of each ellipse are calculated;

step two: calculating average values of the major axis, the minor axis and the rotation angle based on the calculated major axis, minor axis and rotation angle of each ellipse;

step three: constructing a reference ellipse based on the average values of the major axis, the minor axis and the rotation angle, and solving the area of the reference ellipse;

when it is satisfied with

If so, judging the pixel as a point with uneven brightness; wherein S is the difference between the area of any one ellipse and the area of the reference ellipse,

the area of the reference ellipse.

If the phase difference calculated by the phase difference formula is not close to 0 degree or 180 degrees, the polarized light is circularly polarized light at the moment; three parameters of major axis, minor axis and rotation angle of the ellipse of all the ellipses are calculated by an ellipse formula; then, the calculated major axis, minor axis and rotation angle are averaged, respectively. Calculating and constructing a reference ellipse according to the average value of the major axis, the minor axis and the rotation angle, wherein the reference ellipse has an area of

Then calculating a difference set of each elliptical graph and the reference elliptical graph, wherein the area of the difference set is S; setting a threshold value when

Then, the pixel is determined to be an uneven point.

In an embodiment, based on a plurality of pictures correspondingly acquired under a plurality of polarization angles, taking a gray value of a corresponding pixel for each picture specifically includes:

using a polarization camera which is vertical to the screen and is fixed in position to obtain four pictures at four angles of the polarization picker; wherein, the four angles are respectively 0 degree, 45 degrees, 90 degrees and 135 degrees.

In an embodiment, calculating the phase difference of the polarized light when the picture is acquired based on the acquired plurality of gray values specifically includes:

taking the gray values of corresponding pixels for four pictures, wherein the gray values are I ₀ 、I ₄₅ 、I ₉₀ And I ₁₃₅ ；

Based on grey value I ₀ 、I ₄₅ 、I ₉₀ And I ₁₃₅ Parameters of the polarized light are calculated, the parameters including light intensity and phase difference.

The following describes in detail the point of determining whether the pixel brightness is non-uniform by the method for detecting the uniformity of screen color according to the present application with specific embodiments:

the method comprises the following steps: under the condition that the polarization camera is fixed and perpendicular to the screen, four pictures with different analyzer angles are shot, and the corresponding analyzer angles of the four pictures are respectively 0 degree, 45 degrees, 90 degrees and 135 degrees.

Step two: the four gray values for the corresponding pixels are I ₀ 、I ₄₅ 、I ₉₀ And I ₁₃₅ From the four numbers, four parameters A, B of the polarized light and two δ are calculated by a phase difference formula, where a and B are unit light intensities of the polarized light at two angles of the analyzer, and δ is a phase difference at two angles.

The phase difference formula is:

the A and the B are respectively the light intensity of the polarized light when the picture is acquired under any two vertical angles, and the delta is the phase difference of the polarized light when the picture is acquired under any two angles.

Step three: at this time, the calculated δ may include two cases, the first is when the calculated δ is 0 degree or 180 degrees, or close to 0 degree or 180 degrees; the second is when the phase difference is not 0 degrees or 180 degrees.

The first method comprises the following steps: when the calculated delta is 0 degree or 180 degrees or is close to 0 degree or 180 degrees, namely the phase difference is 0 degree or 180 degrees, the polarized light is linearly polarized light; specifically, the polarization azimuth angle of the linearly polarized light of each pixel is calculated, and the correlation process is as follows:

first construct the stocker variables as follows:

s above ₀ 、S ₁ 、S ₂ Is a Stocks variable

Then calculating a polarization azimuth angle through a polarization angle formula;

the formula of the polarization angle is:

alternatively, to reduce errors, the following polarization angle formula may be used to calculate the linear polarization azimuth angle, where the formula is as follows:

wherein, theta represents any polarization azimuth angle,

the mean value of the polarization azimuth angles is obtained, i.e. the truncated mean value is obtained after calculating the linear polarization azimuth angles of each pixel

(i.e., calculating the mean value after deleting some maximum values and minimum values according to the proportion), and setting a threshold value sigma; for the

The pixel of (2) is determined as a point of uneven brightness.

And the second method comprises the following steps: when the delta is not close to 0 degree or 180 degrees, the polarized light is circularly polarized light, the elliptical area corresponding to each pixel and the major axis, the minor axis and the rotation angle of each ellipse are calculated, and the specific steps of the related calculation are as follows:

the first step is as follows: calculating the major axis, the minor axis and the rotation angle of the ellipse through an ellipse calculation formula based on the parameters A and B obtained by the calculation and the phase difference delta;

the ellipse equation is as follows:

wherein a is the major axis of the ellipse, b is the minor axis of the ellipse, and phi is the rotation angle of the ellipse.

The second step is that: acquiring an ellipse major axis, an ellipse minor axis and an ellipse rotation angle of each pixel, then respectively calculating to obtain truncation mean values of the ellipse major axis, the ellipse minor axis and the rotation angle, and constructing a reference ellipse based on the truncation mean values of the ellipse major axis, the ellipse minor axis and the rotation angle; wherein a is the major axis of the ellipse, b is the minor axis of the ellipse, phi is the rotation angle of the ellipse, and the area of the reference ellipse is

The graph of the reference ellipse is shown in fig. 4.

The third step: calculating an ellipse graph formed by the ellipse major axis, the ellipse minor axis and the ellipse rotation angle corresponding to each pixel; calculating an area difference set of each elliptical graph and a reference elliptical graph, wherein the area of the difference set is S; setting a threshold value sigma when

Then, the pixel is determined to be an uneven point.

Further, other types of algorithms are also possible for the above-described similar identification algorithm for elliptically polarized light. For example, phase difference or elliptical rotation angle is used as a similar calculation reference; calculating the truncation mean value, and comparing with a threshold value according to the difference value.

Further, the scores of all the pixels are set according to the two calculation formulas (the similarity calculation methods of the two linear polarizations and the circular polarization), and the operations of blocky uneven point identification, noise point removal and the like are realized by using an image processing technology.

Referring to fig. 3, the present invention captures screen brightness at a plurality of polarization angles using a polarization camera, and then calculates the polarization angle of incident light for each pixel in an acquired image based on the brightness information, thereby evaluating brightness uniformity thereof.

The method requires that the brightness of the backlight source (after the diffusion film is added) is uniform, and the polarization angle of the backlight source after the polarization film is added is uniform. Therefore, in order to improve the quality of the television products and detect the television products more accurately, the method of the invention is used for carrying out three-level detection on the television products.

The following describes in detail the detection of television products by the screen color uniformity detection method according to the present invention with specific embodiments:

and (3) first-stage detection: the backlight after the diffusion film is added is detected, and the backlight after the diffusion film is added is unpolarized light with isotropy and uniform brightness and has no pixel resolution requirement. Therefore, the CCD camera is adopted to vertically shoot the whole screen, and whether the corresponding backlight source meets the requirement or not can be detected; in order to increase the detection granularity, the camera can be slightly translated on the screen plane for multiple times and then shot, and the uniformity of each picture is compared, so that the increase of the detection granularity can be realized; and releasing the qualified product meeting the requirements to the next process.

And (3) second-stage detection: adding a polarizing film for backlight detection, wherein the qualified (diffusion film added) backlight brightness is consistent, and the emergent light brightness is consistent as long as the polarizing direction of the polarizing film is consistent; therefore, the polarization direction detection method can be adopted to detect whether the polarization directions are consistent, and if the polarization directions are consistent, the next procedure can be carried out for the third-level detection.

And (3) third-level detection: mainly detecting the uniformity of the screen; in the two detections, the backlight sources with consistent brightness except for consistent polarization direction are screened; therefore, the screen brightness is completely determined by the polarization angle, and the detection of the polarization angle in the third and the detection can realize the detection of the uniformity of the screen brightness.

The three-level detection scheme can realize accurate detection and control of each link of backlight processing, and finally realize detection of screen brightness. Meanwhile, the brightness of a plurality of pictures shot in multiple regions can be adjusted as a reference based on the calculation of the polarization direction of light rays emitted by the screen, so that the basis for the multi-picture fusion of the next detection of the screen based on multiple times of shooting is provided.

In the embodiment, if the screen backlight does not meet any level of detection, the screen is judged to have non-uniform brightness. This application realizes the complete closed loop detection from the backlight to the screen degree of consistency through the detection of cubic to the screen, can provide the data basis for production management and technology promotion.

Based on the above-mentioned screen color uniformity detection method, the present embodiment provides a computer-readable storage medium, which stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps in the screen color uniformity detection method as described in the above embodiment.

Based on the above method for detecting the uniformity of screen color, the present application further provides a terminal device, as shown in fig. 5, which includes at least one processor (processor) 20; a display screen 21; and a memory (memory)22, and may further include a communication interface (communication interface)23 and a bus 24. The processor 20, the display 21, the memory 22 and the communication interface 23 can communicate with each other through the bus 24. The display screen 21 is configured to display a user guidance interface preset in the initial setting mode. The communication interface 23 may transmit information. The processor 20 may invoke logic instructions in the memory 22 to perform the screen color uniformity detection method in the above-described embodiment.

Furthermore, the logic instructions in the memory 22 may be implemented in software functional units and stored in a computer readable storage medium when sold or used as a stand-alone product.

The memory 22, which is a computer-readable storage medium, may be configured to store a software program, a computer-executable program, such as program instructions or modules corresponding to the methods in the embodiments of the present disclosure. The processor 20 executes the functional application and data processing, i.e. implements the method in the above-described embodiments, by executing the software program, instructions or modules stored in the memory 22.

The memory 22 may include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function; the storage data area may store data created according to the use of the terminal device, and the like.

Further, the memory 22 may include a high speed random access memory and may also include a non-volatile memory. For example, various media that can store program codes, such as a usb disk, a removable hard disk, a Read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk, may also be transient storage media.

The beneficial effect of this application lies in:

1. according to the method, the screen is detected for three times, so that the complete closed-loop detection from the backlight source to the uniformity of the screen is realized, and a data basis can be provided for production management and process improvement; the picture is obtained by fixed shooting, the requirement of consistency of conditions required by the fact that the screen needs to be detected by moving for multiple times of shooting is avoided, the problem of brightness difference of polarized light caused by multiple observation angles in screen detection is solved, and support is provided for feasible large-screen brightness uniformity. Compared with the traditional method, the scheme can realize automatic detection, reduce the manual burden and improve the product quality and consistency.

2. According to the method and the device, the screen picture is acquired through the fixed position, the screen is automatically detected, the vision of people who consume people in human eye detection is avoided, and the problems that the accuracy and the stability of detection are insufficient are solved.

3. According to the method and the device, three-level detection is completed based on the method and the device, complete closed-loop detection from the backlight source to the screen uniformity is realized, and a data basis can be provided for production management and process promotion.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (3)

1. A screen color uniformity detection device, comprising:

a camera for capturing an image;

the analyzer is arranged on the camera and converts light rays passing through the analyzer into polarized light with a set angle;

the angle adjuster is connected with the analyzer, and the analyzer is driven to rotate through the movement of the angle adjuster, so that the polarization angle of the analyzer is changed, and the camera can shoot images at different polarization angles;

the controller is connected with the camera, controls the camera to shoot images and analyzes and detects the images shot by the camera, and is also connected with the angle adjuster to control the angle adjuster to move;

the polarization analyzer comprises a polarization film and a rotating gear, the polarization film is arranged in the rotating gear, and the rotating gear is meshed with a motor gear on the angle regulator;

the angle regulator also comprises a motor, the controller is connected with the motor and drives the motor to rotate, and a motor gear is arranged on the motor;

the detection device further comprises an encoder, the encoder is arranged on the motor and used for detecting the rotating angle of the motor, and the controller is connected with the encoder to obtain the angle detected by the encoder.

2. The screen color uniformity detection device of claim 1, further comprising a lens between the camera and the analyzer for collecting polarized light after passing through the analyzer.

3. The screen color uniformity detection device of claim 1, wherein an alert module is disposed on the controller.

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