CN110060625A - A kind of LED display acquisition vignetting compensation method - Google Patents
A kind of LED display acquisition vignetting compensation method Download PDFInfo
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- CN110060625A CN110060625A CN201910500640.1A CN201910500640A CN110060625A CN 110060625 A CN110060625 A CN 110060625A CN 201910500640 A CN201910500640 A CN 201910500640A CN 110060625 A CN110060625 A CN 110060625A
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
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Abstract
A kind of LED display acquisition vignetting compensation method, it is related to LED alignment technique field, solve the problems, such as that existing display screen acquisition correction process makes the show uniformity of display screen after correcting by destruction due to the vignetting of camera, the present invention utilizes the brightness fluctuation characteristic of LED itself, using iteration acquisition method, influence of the brightness fluctuation to camera acquisition vignetting is eliminated by carrying out processing to multi collect data, to obtain camera acquisition vignetting curved surface, and it compensates, compensation method of the present invention can obtain accurately, true brightness of display screen difference, display effect after ensuring to correct.The invention can ensure that acquiring the authenticity of data in the same aperture focal length of camera, absolute brightness uniformity correction can be realized.The present invention can be applied according to different display screens, have versatility, and easy to operate, be suitble to engineer application.
Description
Technical field
The present invention relates to LED alignment technique fields, and in particular to a kind of LED display acquisition vignetting compensation method.
Background technique
With the continuous development of LED display technique, LED display is towards ultra high density, extra small spacing, oversize direction
Gradually develop, to the show uniformity of display screen, more stringent requirements are proposed.Since LED light emission luminance has discrete type, so
To ensure that the show uniformity of LED must be applied to alignment technique, each display pixel is made to apply acquisition correction technology
Brightness is consistent afterwards.And acquisition correction technology an important factor for being achieved is can accurately to obtain each display picture of LED display
The brightness of element, thus the brightness for how accurately obtaining display screen display pixel become uniformity an important factor for being guaranteed it
One.
The brightness of display screen display pixel is mainly obtained by camera acquisition at present, and camera is due to the optics of itself
Characteristic is mainly reflected in that the data of acquisition are broad in the middle, surrounding is small there is gradual halation phenomena；Bright among the image of acquisition, surrounding is dark,
The accuracy for seriously affecting display screen display pixel luminance acquisition, the display screen appearance after making correction is intermediate dark, and surrounding is bright to be showed
As influencing show uniformity.Simultaneously as the brightness discreteness of LED display itself, there are luminance differences for each display pixel
Different, which mixes with the vignetting of camera and is superimposed, and increases the difficulty of camera vignetting compensation, corrects display screen
Uniformity afterwards is destroyed further.
To solve the above-mentioned problems, main method is individually to be marked to camera using integrating sphere and uniform blank at present
Fixed, still, this calibration mode is only suitable for fixed aperture and fixed focal length, when the focal length of camera and with display screen it is opposite away from
It when from changing, needing to re-scale, and the price of integrating sphere is high, demarcates a process complexity, not have universal and not
It is suitble to practical implementation.So how accurately to obtain the vignetting curve of camera acquisition and carried out to the vignetting of camera acquisition
Compensation, is a problem of acquisition correction.
Summary of the invention
The present invention is to solve existing display screen acquisition correction process since the vignetting of camera makes the display of display screen after correction
The problem of uniformity is by destroying provides a kind of camera vignetting compensation method in LED display acquisition correction.
A kind of LED display acquisition vignetting compensation method, this method are realized by following steps:
Step 1: k display screen of setting, the pixel quantity that each display screen is shown is m × n, selects one of display
Screen carries out positioning test with camera, is overlapped camera optical axis and the normal of the display screen, and display location is in camera view frame
Middle；Fixed camera and display screen respectively, adjust the aperture and focal length of camera, camera are made clearly to acquire the every of display screen
One display pixel, the aperture and focal length of fixed camera；The k >=10, m are display screen line pixel quantity, and n is display screen column picture
Prime number amount；
Step 2: the pixel of camera k display screen described in step 1 is successively acquired, each display is obtained
The brightness data L of each display pixel of screeni(m×n), Gauss two-dimensional filtering is carried out to the k brightness datas respectively, is obtained
Brightness data LG after Gauss two-dimensional filteringi(m×n)；
By the k brightness data LG through Gauss 2-d gaussian filtersi(m×n)The pixel of same coordinate position be overlapped,
The pixel and L of same coordinate position after being superimposedsum(m×n)；
Step 3: to the pixel and L of same coordinate position after the superposition of step 2 acquisitionsum(m×n)Pixel is carried out to be returned
One changes, and obtains the vignetting curved surface Lo of camera acquisition(m×n), indicated with following formula are as follows:
In formula, max (Lsum(m×n)) it is Lsum(m×n)Maximum value.
Step 4: the vignetting curved surface Lo that step 3 is obtained(m×n)It is inverted, obtain camera vignetting compensation curved surface Lo'(m×n),
Again by the camera vignetting compensation curved surface Lo'(m×n)Respectively with the brightness data L of the display pixel of k display screeni(m×n)Corresponding position
Pixel multiplication is set, the brightness collection value after obtaining camera vignetting compensation realizes the vignetting compensation of camera.
Beneficial effects of the present invention: the method for the present invention discrete feature intrinsic according to LED, it is folded using multi collect
Adding method obtains the Proximal surface of camera vignetting, then acquires compensation curved surface, to realize vignetting compensation.Before present invention correction
Integrating sphere standardization saved cost, and can be applied according to different display screens, there is versatility, and easy to operate,
It is suitble to engineer application.
Method of the invention utilizes the brightness fluctuation characteristic of LED itself, using iteration acquisition method, by multi collect
Data carry out processing and eliminate influence of the brightness fluctuation to camera acquisition vignetting, to obtain camera acquisition vignetting curved surface, and carry out
Compensation obtains accurately, true brightness of display screen difference, it is ensured that the display effect after correction.The invention can ensure that in camera
The authenticity that data are acquired in the case of same aperture focal length, can be realized absolute brightness uniformity correction.
Detailed description of the invention
Fig. 1 is the positional diagram of camera and display screen；
Fig. 2 is the effect data figure of camera acquisition；
After Fig. 3 acquires vignetting figure by superposition for camera in LED display of the present invention acquisition vignetting compensation method
Obtained camera acquisition vignetting curved surface effect picture；
Fig. 4 is the compensation song that LED display of the present invention acquires that the camera in vignetting compensation method acquires vignetting figure
Face effect picture；
Fig. 5 is the LED display in LED display of the present invention acquisition vignetting compensation method after vignetting compensation
The brightness data effect picture of each display pixel；
Fig. 6 is the flow chart that LED display of the present invention acquires vignetting compensation method.
Specific embodiment
Specific embodiment one illustrates present embodiment, a kind of LED display acquisition vignetting compensation side in conjunction with Fig. 1 to Fig. 6
Method is realized especially by following steps:
Step 1: set same model display screen quantity to be corrected as k, i=1,2, and 3.....k, k >=10, each display screen
Display pixel quantity is m × n, and m is display screen line pixel quantity, and n is display screen column pixel quantity.Each display screen is compiled
Number, if one of display screen is B, the relative position of the block display screen and camera is mixed up, the discovery and camera light of display screen are made
Overlapping of axles, and display location is in the middle of camera view frame.Fixed camera position mixes up the aperture and focal length of camera, fixed
The aperture and focal length of camera.
Step 2: k block display screen is individually placed to first piece of display screen BiPosition at, successively collect every piece of display
The brightness data L of each display pixel of screeni(m×n), respectively to k Li(m×n)Gauss two-dimensional filtering is carried out, high-frequency noise is eliminated,
Shown in two-dimensional Gaussian function such as formula (1):
Wherein x ∈ m, y ∈ n, (x, y) is Li(m×n)In any point coordinate.G (x, y) is dimensional Gaussian convolution kernel.
If the brightness data after 2-d gaussian filters is LGi(m×n)。
K display screen is passed through to the LG of 2-d gaussian filtersi(m×n)The pixel of same coordinate position be overlapped, it is such as public
Shown in formula (2):
Wherein Lsum(m×n)For LGi(m×n)Same coordinate position pixel and.
Step 3: to Lsum(m×n)All pixels are normalized, and obtain the vignetting curved surface Lo of camera acquisition(m×n), such as formula
(3) shown in:
Step 4: by Lo(m×n)It is inverted to obtain vignetting compensation curved surface, as shown in formula (4):
Wherein Lo'(m×n)For camera vignetting compensation curved surface.
Step 5: again by camera vignetting compensation curved surface Lo'(m×n)Respectively with the L of k display screeni(m×n)Corresponding position pixel
It is multiplied, the brightness collection value after obtaining camera vignetting compensation, as shown in formula (5):
L'i(m×n)=Lo'(m×n)×Li(m×n) (5)
Specific embodiment two illustrates that present embodiment, present embodiment are specific embodiment one in conjunction with Fig. 1 to Fig. 6
A kind of embodiment of the LED display acquisition vignetting compensation method:
Step 1: as shown in Figure 1, the square display screen for being in total 320 × 320 to k (k >=10) block pixel needs to carry out
Acquisition correction takes one of display screen B and camera to carry out positioning test, and camera optical axis is perpendicular to display screen, and and display screen
Normal is overlapped, and adjusts camera optical axis and display screen normal distance is 2 meters, position is fixed, and screen position is also fixed not
It is dynamic.Then the aperture and focal length for adjusting camera enable camera clearly to acquire each display pixel of display screen, fixed light
Circle and focal length.
Step 2: k block display screen is successively placed on B display screen same position, with camera successively to k block display screen such as Fig. 2
It is acquired, obtains each pixel brightness data L of every piece of display screeni(320×320)。
Step 3: respectively to k Li(320×320)Gauss two-dimensional filtering is carried out, eliminates high-frequency noise, two-dimensional Gaussian function is such as
Shown in formula (1):
Wherein x ∈ m, y ∈ n, (x, y) is Li(320×320)In any point coordinate.G (x, y) is dimensional Gaussian convolution
Core.If the brightness data after 2-d gaussian filters is LGi(320×320).By k display screen by 2-d gaussian filters
LGi(320×320)The pixel of same coordinate position be overlapped, as shown in formula (2):
Wherein Lsum(320×320)For LGi(320×320)Same coordinate position pixel and.
Step 4: as shown in figure 3, by Lsum(320×320)It is normalized, obtains camera acquisition vignetting curved surface.Such as formula (3)
It is shown:
Wherein Lo(320×320)Vignetting curved surface is acquired for camera, vignetting curved surface size is 320 × 320, with display screen matrix number
Amount is consistent.
Step 5: as shown in figure 4, by Lo(m×n)It is inverted to obtain vignetting compensation curved surface, as shown in formula (4):
Wherein Lo'(320×320)For camera vignetting compensation curved surface.
Step 6: again by camera vignetting compensation curved surface Lo'(320×320)Respectively with the L of k display screeni(320×320)Corresponding position
Pixel is multiplied, the brightness collection value after obtaining camera vignetting compensation, i.e., true brightness data.As shown in formula (5):
L'i(320×320)=Lo'(320×320)×Li(320×320) (5)
Method described in present embodiment utilizes the brightness discrete feature of each display pixel of LED display, by more
A display screen carries out successively independent data acquisition, and corresponds to display pixel to all acquisition data and be overlapped summation and obtain
Camera acquires vignetting curve, and compensates to it, is suitable for engineer application.
Claims (3)
1. a kind of LED display acquires vignetting compensation method, characterized in that this method is realized by following steps:
Step 1: setting k display screen, the pixel quantity that each display screen show be m × n, select one of display screen and
Camera carry out positioning test, be overlapped camera optical axis and the normal of the display screen, and display location in camera view frame just
It is intermediate；Fixed camera and display screen respectively, adjust the aperture and focal length of camera, make camera clearly acquire display screen each
Display pixel, the aperture and focal length of fixed camera；The k >=10, m are display screen line pixel quantity, and n is display screen column pixel number
Amount；
Step 2: the pixel of camera k display screen described in step 1 is successively acquired, each display screen is obtained
The brightness data L of each display pixeli(m×n), 2-d gaussian filters are carried out to the k brightness datas respectively, obtain two dimension
Brightness data LG after gaussian filteringi(m×n)；
Brightness data LG by k display screen through 2-d gaussian filtersi(m×n)The pixel of same coordinate position be overlapped, obtain
The pixel and L of same coordinate position after must being superimposedsum(m×n)；
Step 3: to the pixel and L of same coordinate position after the superposition of step 2 acquisitionsum(m×n)Pixel is carried out to be normalized,
Obtain the vignetting curved surface Lo of camera acquisition(m×n), indicated with following formula are as follows:
In formula, max (Lsum(m×n)) it is Lsum(m×n)Maximum value；
Step 4: the vignetting curved surface Lo that step 3 is obtained(m×n)It is inverted, obtain camera vignetting compensation curved surface Lo'(m×n), then will
The camera vignetting compensation curved surface Lo'(m×n)Respectively with the brightness data L of the display pixel of k display screeni(m×n)Corresponding position picture
Element is multiplied, and the brightness collection value after obtaining camera vignetting compensation realizes the vignetting compensation of camera.
2. a kind of LED display according to claim 1 acquires vignetting compensation method, it is characterised in that: right in step 2
The k brightness data Li(m×n)2-d gaussian filters are carried out, the brightness data LG after obtaining 2-d gaussian filtersi(m×n)；
Two-dimensional Gaussian function is indicated with following formula are as follows:
In formula, x ∈ m, y ∈ n, (x, y) is Li(m×n)In any point coordinate, G (x, y) is dimensional Gaussian convolution kernel；
LG by k display screen through 2-d gaussian filtersi(m×n)The pixel of same coordinate position be overlapped, indicated with following formula
Are as follows:
Wherein Lsum(m×n)For LGi(m×n)Same coordinate position pixel and.
3. a kind of LED display according to claim 1 acquires vignetting compensation method, it is characterised in that:, will in step 4
Vignetting curved surface Lo(m×n)It is inverted, vignetting compensation curved surface is obtained, is indicated with following formula are as follows:
Wherein Lo'(m×n)For camera vignetting compensation curved surface.
Again by camera vignetting compensation curved surface Lo'(m×n)Respectively with the L of k display screeni(m×n)Corresponding position pixel is multiplied, and obtains phase
Brightness collection value after machine vignetting compensation, is formulated are as follows:
L'i(m×n)=Lo'(m×n)×Li(m×n)。
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Cited By (3)
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| CN111179815A (en) * | 2020-01-07 | 2020-05-19 | 长春希达电子技术有限公司 | Method for collecting and correcting normal brightness and chromaticity of LED display module |
| CN112929623A (en) * | 2021-03-02 | 2021-06-08 | 卡莱特云科技股份有限公司 | Lens shadow repairing method and device applied to whole screen in correction process |
| CN116913206A (en) * | 2023-09-05 | 2023-10-20 | 长春希达电子技术有限公司 | Flat field correction method for LED box display screen |
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| CN116913206B (en) * | 2023-09-05 | 2023-12-12 | 长春希达电子技术有限公司 | Flat field correction method for LED box display screen |
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