CN108986170A - A kind of line-scan digital camera method for correcting flat field suitable for field working conditions - Google Patents
A kind of line-scan digital camera method for correcting flat field suitable for field working conditions Download PDFInfo
- Publication number
- CN108986170A CN108986170A CN201810720139.1A CN201810720139A CN108986170A CN 108986170 A CN108986170 A CN 108986170A CN 201810720139 A CN201810720139 A CN 201810720139A CN 108986170 A CN108986170 A CN 108986170A
- Authority
- CN
- China
- Prior art keywords
- coefficient
- matrix
- line
- digital camera
- checked
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/80—Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
Landscapes
- Engineering & Computer Science (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Abstract
The invention discloses a kind of line-scan digital camera method for correcting flat field suitable for field working conditions, the initial gray value matrix that shooting obtains screen initial row to be checked obtains original calibration coefficient matrix；The gray-value image of line-scan digital camera scanning shoot screen to be checked obtains original gradation value matrix；The corresponding original calibration coefficient multiplied by respective column of original gradation value matrix is obtained to the gray scale value matrix of preliminary corrections；, divided by the median of the row, the pixel response nonuniformity property coefficient of initial row in screen image prime matrix to be checked will be determined by each grey scale pixel value in the gray scale value matrix of preliminary corrections；Effective flat field correction coefficient is obtained, the gray-value image of line-scan digital camera shooting is corrected.The method of technical solution of the present invention, the not high problem of the difference of working environment, precision is difficult to adapt to for the method for correcting flat field of current line-scan digital camera, in the case where actual condition, flat field correction is carried out to line-scan digital camera by the combination of optics and algorithm, adaptability is good, accuracy is high.
Description
Technical field
The invention belongs to the flat field correction technical fields of line-scan digital camera, are based especially on the panel defect detection of line-scan digital camera
A kind of preceding alignment technique, and in particular to line-scan digital camera method for correcting flat field suitable for field working conditions.
Background technique
In machine vision, according to the difference of sensor pixel arrangement mode, camera can be distinguished area array cameras and line
Array camera.Area array cameras, the i.e. target surface of sensor are a faces, and use is very universal.And line-scan digital camera, sensor pixel point
" line " shape is presented in cloth, i.e. pixel only has a line arrangement.Line-scan digital camera has higher precision for area array cameras.Line
The visual field of array camera shooting is elongated band, is chiefly used in Scanning Detction, scans the screen to be checked at the uniform velocity moved, line-scan digital camera is clapped
The synthesis for individual picture taken the photograph generates the shooting picture of secondary complete a panel or screen to be checked.
Line-scan digital camera before the use, needs to carry out flat field correction.When the target using line-scan digital camera shooting brightness uniformity
When object, obtained shooting picture should be brightness uniformity, the true characteristic for reacting target object.And actual photographed picture
In be brightness irregularities, i.e., the gray scale of each pixel is different in image, can not really reflect the object that is taken
The surface characteristic of body.Line-scan digital camera is generally used for defective detection, so this missed by camera system bring itself
Difference be do not allow it is existing.Typically resulting in the inconsistent source of error of gray value has, uneven, optical center and the camera lens of light source
Edge is to each pixel of the non_uniform response and sensor of light to the responsiveness difference of incident light.If therefore camera
Without carrying out flat field correction, then it will lead in actual use using preceding, image quality impacted.
Flat field correction is exactly to correct since other factors bring picture imagewise uniform except screen to be checked defect itself
Influence.Including: m indicates that the illumination intensity non-uniformity coefficient along strip source direction, n indicate that camera lens responds light
Inhomogeneities coefficient, p indicate that the Non-uniform responsivity property coefficient of each pixel of line-scan digital camera, q indicate each position pair of screen to be checked
The reflection inhomogeneities coefficient of light.Flat field correction needs correction, and wherein m, tri- coefficients of n, p, and tri- coefficients of m, n, p are equal to 1
When mean this parameter without correction.It is as shown in Figure 1 a kind of use structure of typical linear array scanning camera, item
The incident light that shape light source issues is irradiated in plane to be checked (generally glass, steel plate or liquid crystal display panel etc.), and light is by anti-
It penetrates, is acquired by the line-scan digital camera of the other side.Camera shoots the surface characteristics of a line in plane to be checked every time, under screen to be checked passes through
When the conveyer belt in face at the uniform velocity moves, line-scan digital camera can shoot entire screen surfaces to be checked, therefore camera can be to entire to be checked
Screen surfaces imaging.When not having defect in plane to be checked, the picture of camera output should be the picture of an inhomogeneous intensity.Work as screen surfaces
When existing defects, the defect of screen surfaces will change the reflecting effect of light, and the intensity for being incident on line-scan digital camera light will
It can change, therefore, by detecting the gray value for the picture shot, can detecte out the defect of screen surfaces.If the phase used
Machine does not pass through flat field correction, then camera lens is to central ray and rim ray due to the homogeneity question of strip source itself
Response consistency problem and each pixel responsiveness of camera difference, even if shooting one piece of flawless surface screen when, figure
Piece still can show that gray value is uneven, therefore cause the erroneous detection in detection, reduce the precision of detection.Therefore, linear array phase
Flat field correction work before machine use is necessary.
There are two ways to existing flat field correction, one is be corrected before camera lens shipment in producer.According to preceding
Face is analyzed, and the factor of the existing camera lens of inhomogeneities is imaged in system bring, also there is the Producing reason of light source.In producer
The inhomogeneities for the light source that camera lens flat field correction is usually ignored itself is carried out, and correction bring influences.Correcting plate is
A kind of plate specially designed and produced for flat field correction, it is desirable that itself cannot have any defect, for high-precision application
Scene, it is expensive.Likewise, producer working environment and actual job site working environment there are also difference, such as carry on the back
Scape stray light, operating distance are adjusted, these external factor can not be consistent with Field adjustment, cause flat field correction effect to exist certain
Problem.Another bearing calibration is directly to install the correction of laggard line array camera at the scene.This bearing calibration and reality
Working condition is consistent, eliminates light source, background stray light, and operating distance adjusts bring error.But used correcting plate
Still uncertainty can be brought.It is higher that line-scan digital camera shoots precision, if correcting plate itself haves the defects that certain, corrects
The error that will inevitably bring correcting plate to introduce in the process.In addition, on some mounted workbench, due to space
Narrow, correcting plate can not be placed in the visual field of actual camera shooting and carry out flat field correction by the reasons such as mechanism sealing, therefore
Correcting plate cannot be used to be shot.
In addition, in the prior art, CN102479005A discloses a kind of method for correcting flat field of two-dimension optical detection, lead to
Overcorrect circuit realizes the correction of two-dimension optical intensity, and to introduce correcting circuit mean that device itself to be corrected can not be utilized
Flat field correction is realized, other than needing to consider correction cost, it is also necessary to consider range and the space of correction.CN105701209A is then
A kind of usual bearing calibration based on line-scan digital camera scanning is disclosed, key is to obtain using line-scan digital camera shooting red green
The grayscale image of blue three-color calculates the correction coefficient curve for obtaining each color, thus realize to line-scan digital camera scan image into
The shortcomings that row flat field correction, this mode, is to need to carry out gray value calculating respectively for each color and obtain corresponding school
Positive curve calculates complexity, and corrected result is not very accurate respectively for each color.
Summary of the invention
Aiming at the above defects or improvement requirements of the prior art, the present invention provides a kind of linear arrays suitable for field working conditions
Camera method for correcting flat field.The method of technical solution of the present invention is difficult to adapt to for the method for correcting flat field of current line-scan digital camera
The not high problem of difference, the precision of working environment, in the case where actual condition, by the combination of optics and algorithm to linear array phase
Machine carries out flat field correction, and adaptability is good, accuracy is high.
To achieve the above object, according to one aspect of the present invention, a kind of linear array phase suitable for field working conditions is provided
Machine method for correcting flat field, which is characterized in that
S1 obtains the initial gray value matrix of screen image prime matrix arbitrary initial row to be checked using line-scan digital camera shooting, utilizes institute
It states initial gray value image array image and obtains original calibration coefficient matrix；
S2 at the uniform velocity moves screen to be checked, the gray-value image of line-scan digital camera scanning shoot screen to be checked, according to on-screen pixels to be checked
The position distribution of coordinate obtains the original gradation value matrix of screen to be checked；
S3 is corresponding multiplied by the original calibration coefficient matrix by the gray value of every a line in the original gradation value matrix
The original calibration coefficient of respective column obtains the gray scale value matrix of preliminary corrections；
S4 obtains the median by each grey scale pixel value in the gray scale value matrix of preliminary corrections divided by the row
Coefficient matrix is simultaneously analyzed, and determines the imaging inhomogeneities coefficient of initial row in screen image prime matrix to be checked；
S5 is corresponding with the column according to the pixel response nonuniformity property coefficient for being often listed in initial row in screen image prime matrix to be checked
Original calibration coefficient obtains effective flat field correction coefficient of line-scan digital camera, carries out school to the gray-value image of line-scan digital camera shooting
Just.
One as technical solution of the present invention is preferred, includes in step S1,
S11 obtains the initial gray value matrix of screen image prime matrix initial row to be checked using line-scan digital camera shooting, determine described in
The median of each pixel coordinate gray value in initial gray value matrix；
S12 obtains screen to be checked successively by the gray value of each pixel in the row initial gray value matrix divided by median
Pixel coefficient of the pixel of other coordinates with respect to median in the initial gray image of initial row；
S13 is sequentially inverted to the pixel coefficient according to pixel coordinate in initial gray image, obtains screen each column to be checked
Original calibration coefficient, constitute original calibration coefficient matrix.
Preferably as one of technical solution of the present invention, step S4 includes,
S41 is analyzed by the gray scale value matrix of preliminary corrections, obtains the median of every a line gray value in matrix；
The gray value of each row of gray scale value matrix successively divided by the median of the row, is obtained coefficient matrix by S42；
S41 analyzes the coefficient matrix by column, compares the size of each column coefficient；
If having no less than 90% coefficient value equal with the coefficient value of the column coefficient initial row in the S42 column coefficient, really
The pixel response nonuniformity property coefficient of the fixed column coefficient initial row corresponding position is the inverse of the coefficient value of the column coefficient initial row；
S43 obtains the pixel response nonuniformity property coefficient of each column of coefficient matrix, constitutes the pixel response of line-scan digital camera not
Uniformity coefficient matrix.
Preferably as one of technical solution of the present invention, step S5 includes,
S51 determines that effective flat field correction coefficient of line-scan digital camera multiplies for the pixel response nonuniformity property coefficient of each column initial row
With the corresponding original calibration coefficient of the column；
S52 shoots the gray-value image of screen to be checked using line-scan digital camera, and the gray value of each column pixel is corresponding multiplied by the column
Effective flat field correction coefficient, obtains the true picture Jing Guo flat field correction.
One as technical solution of the present invention is preferred, the initial gray value matrix of screen image prime matrix arbitrary initial row to be checked
The initial gray value matrix of screen image prime matrix the first row preferably to be checked.
Preferably as one of technical solution of the present invention, screen to be checked is preferably disposed on transmission microscope carrier in step S2, and transmission carries
Platform is at the uniform velocity mobile to drive screen to be checked at the uniform velocity to move.
One as technical solution of the present invention is preferred, screen image prime matrix, original gradation value matrix and coefficient matrix to be checked
Row, column number difference it is equal.
One as technical solution of the present invention is preferred, and pixel coefficient k preferably has following calculation formula,
K=m*n*p*q；
Wherein, m is the illumination intensity non-uniformity coefficient along strip source direction；N is camera lens to light Non-uniform responsivity
Property coefficient；P is the Non-uniform responsivity property coefficient of each pixel of line-scan digital camera, and q is that screen image vegetarian refreshments to be checked is uneven to the reflection of light
Even property coefficient.
One as technical solution of the present invention is preferred, and screen image vegetarian refreshments to be checked preferably exists to the reflection inhomogeneities coefficient of light
It is equal to 1 when pixel zero defect, 1 is not equal to when defective.
One as technical solution of the present invention is preferred, the coefficient L of each pixel in coefficient matrixj,iIt is preferred that just like
Lower calculation formula:
Lj,i=qj,i/q1,i；
Wherein, qj,iThe pixel arranged for jth row i-th on screen to be checked is to the reflection inhomogeneities coefficient of light.
In general, through the invention it is contemplated above technical scheme is compared with the prior art, have below beneficial to effect
Fruit:
1) method of technical solution of the present invention does not require the correction environment of line-scan digital camera, line-scan digital camera corrector loop
Border can be standard correction environment, or actual condition, there is no due to external environment it is inconsistent caused by operating distance,
Correction error caused by the irrelevant factors such as background stray light, adaptability is high, and calibration accuracy is high.
2) method of technical solution of the present invention, line-scan digital camera bearing calibration is simply easily operated, directly makes in correction course
Line-scan digital camera is corrected with screen to be checked, does not need that correcting plate additionally is added, correction cost is low, narrow for closed
Actual working conditions have good adaptability.
3) method of technical solution of the present invention, by the combination of optics and algorithm, for can in line-scan digital camera use process
The factor that its measurement accuracy can be will affect is corrected respectively according to classification, and new correction error is not introduced in correction course,
The calculating of correction coefficient is simple, and correction result accuracy is high.
Detailed description of the invention
Fig. 1 is line-scan digital camera working principle diagram in the embodiment of technical solution of the present invention.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.As long as in addition, technical characteristic involved in the various embodiments of the present invention described below
Not constituting a conflict with each other can be combined with each other.The present invention is described in more detail With reference to embodiment.
In the present embodiment, for line-scan digital camera working principle as shown in Figure 1,1 be wherein camera sensor, 2 be camera lens, 3 for
Inspection screen, 4 be strip source.
In the usual correction course of actual line-scan digital camera, the influence in view of many factors is needed, wherein mainly including
Following factor: m indicates that the illumination intensity non-uniformity coefficient along strip source direction, n indicate that camera lens responds not light
Uniformity coefficient, p indicate that the Non-uniform responsivity property coefficient of each pixel of line-scan digital camera, q indicate each position of screen to be checked to light
Reflection inhomogeneities coefficient.In general, m, n, p are caused the reason of these three coefficients are line-scan digital cameras itself, flat field school
Just needing most correction is exactly m, these three coefficients of n, p.But it in fact, is inevitably introduced in flat field correction to be checked
Shield (or calibration plate, screen hereinafter referred to as to be checked) itself for light reflection inhomogeneities coefficient p.The purpose of the present embodiment is just
It is the usual bearing calibration of line-scan digital camera for proposing a kind of non-uniformity problem of reflection to light that is intended to evade screen to be checked, thus complete
Pairs of m, n, the precise calibration of tri- coefficients of p.
Although the picture that these factors of m, n, p, q can all shoot line-scan digital camera leads to the problem of flat field, wherein m,
These three factors of n, p are derived from the reason of other than screen to be checked (or calibration plate), carry out shooting inspection using line-scan digital camera practical
When survey, advance correction is needed to eliminate.And q is screen built-in problem to be checked, this and screen to be checked itself have close
The relationship cut, the reflection unevenness property coefficient of each piece of screen to be checked all can difference.Therefore, line-scan digital camera is put down in order to realize
Correction is as accurate as possible, needs to m, before tri- coefficients of n, p are corrected, first to existing for screen to be checked itself to light
Reflection inhomogeneities coefficient is corrected.It should be noted that the screen surfaces no significant defect to be checked of manufacturer's production, it can false
If most of region is 1 to the reflection coefficient of light on screen, there is the picture that a small number of (being less than 10%) response coefficients are not equal to 1 in every a line
Element.
Before specifically correct, in order to measure with for the sake of convenience of calculation, entire screen to be checked is divided into several pictures
The pixel matrix (M*N matrix) of vegetarian refreshments composition, line-scan digital camera is shot every time, can all obtain a gray scale value matrix (1*N square
Battle array).
Specifically, in the present embodiment, the flat field correction step of line-scan digital camera includes:
The first step obtains the original calibration coefficient matrix of screen to be checked.Tested screen is placed in camera fields of view first, linear array
Camera shoots the first picture, i.e. initial gray value matrix (1*N matrix), and the of screen image prime matrix (M*N matrix) preferably to be checked
A line confirms the gray value of each pixel in this picture, i.e., the gray scale of each pixel in confirmation initial gray value matrix
Value, finds the median of grey scale pixel value in picture, and record the corresponding pixel of this median in initial gray value matrix
With the coordinate a in screen image prime matrix to be checked.Then successively distinguished using the gray value of other each pixels in this picture
Divided by this median, other pixels are successively obtained for the coefficient value k of this position, so as to form a new ratio
Matrix (1*N matrix).
In fact, there are following relationships, i.e., between above-mentioned coefficient value k and the influence factor of line-scan digital camera
K=m*n*p*q,
It for example, is exactly k for pixel specific for each in picture element matrix the first row1, i=m1, i*n1, i*p1, i*
q1, i.Wherein the subscript 1 of k, m, n, p, q indicate the first row, i.e. the first picture (initial gray value matrix) only has a line, subscript i
Indicate the i-th column, maximum number of column N.On this basis, can further obtain original calibration coefficient is 1/k1, i, constitute screen to be checked
Original calibration coefficient matrix, as shown in table 1 below, wherein k1, a=1.
| K1,1 | K1,2 | K1,3 | ... | K1, a | ... | k1, N-1 | K1, N |
The original calibration coefficient matrix of the screen to be checked of table 1
Second step starts the transmission microscope carrier below screen to be checked, makes screen to be checked start at the uniform velocity to move, line-scan digital camera uniform speed scanning
Shooting screen obtains whole pictures of shooting screen image prime matrix, the i.e. every row shooting one picture (a 1*N matrix) of picture element matrix,
It is up to M row.In screen image prime matrix to be checked, the pixel gray value of the i-th column of jth row is AJ, i, (M, the picture of whole rows
1*N matrix) combine synthesis one complete screen to be checked original gradation picture (, i.e., the original gray value square of screen to be checked
Battle array, M*N matrix), as shown in table 2 below:
| A1,1 | A1,2 | A1,3 | ... | A1, a | ... | A1, N-1 | A1, N |
| A2,1 | A2,2 | A2,3 | ... | A2, a | ... | A2, N-1 | A2, N |
| A3,1 | A3,2 | A3,3 | ... | A3, a | ... | A3, N-1 | A3, N |
| ... | ... | ... | ... | ... | ... | ... | ... |
| AM-2,1 | AM-2,2 | AM-2,3 | ... | AM-2, a | ... | AM-2, N-1 | AM-2, N |
| AM-1,1 | AM-1,2 | AM-1,3 | ... | AM-1, a | ... | AM-1, N-1 | AM-1, N |
| AM, 1 | AM, 2 | AM, 3 | ... | AM, a | ... | AM, N-1 | AM, N |
The original gradation value matrix of the screen to be checked of table 2
Third step, the original calibration coefficient matrix obtained using the first step carry out the original gradation value matrix of inspection screen preliminary
Correction.By the gray value of every a line of original gradation matrix of table 2, one by one with respective column in the original calibration coefficient matrix in table 1
The correction coefficient of column is multiplied, and obtains new matrix.That is, being directed to each column gray value of original gradation matrix, all successively
The correction coefficient that this column is corresponded to original calibration coefficient matrix is multiplied, i.e., by each the i-th column of the row picture of original gradation value matrix
Plain gray value is multiplied by the correction coefficient 1/K under the pixel coordinate1i, the gray scale value matrix for passing through preliminary corrections is obtained, such as the following table 3 institute
Show:
Table 3
Further, due to have passed through correction coefficient 1/K1iCalculating, line-scan digital camera shooting obtain screen image (M* to be checked
N matrix) on illumination intensity non-uniformity Coefficient m on strip source direction, camera lens to light Non-uniform responsivity property coefficient n, and
The Non-uniform responsivity property coefficient p of each pixel of line-scan digital camera can be corrected.But due to correction coefficient 1/k1iIn include
Screen surfaces to be checked each position to the reflection inhomogeneities coefficient q of light be shooting screen the first row to be checked inhomogeneities system
Number, so the obtained picture of shooting still not instead of not really and accurately picture, by the first row comprising screen surfaces to be checked
Pixel is to the picture after the reflection inhomogeneities coefficient correction of light.Therefore, it is necessary to the picture (gray value by preliminary corrections
Matrix) it needs further to be corrected, to eliminate because reflection inhomogeneities coefficient difference of coefficients existing for screen to be checked itself is led
The error of cause.
4th step, by each pixel of table 3 divided by the median of the row pixel value, every row pixel in gray scale value matrix
Gray value all there is a median.So as to obtain a new coefficient table, i.e., the coefficient square of screen screen volume to be checked to be checked
Battle array, as shown in table 4 below, wherein each coefficient elements L of coefficient matrixjiIt indicates.
| L1,1 | L1,2 | L1,3 | ... | L1, a | ... | L1, N-1 | L1, N |
| L2,1 | L2,2 | L2,3 | ... | L2, a | ... | L2, N-1 | L2, N |
| L3,1 | L3,2 | L3,3 | ... | L3, a | ... | L3, N-1 | L3, N |
| ... | ... | ... | ... | ... | ... | ... | ... |
| LM-2,1 | LM-2,2 | LM-2,3 | ... | LM-2, a | ... | LM-2, N-1 | LM-2, N |
| LM-1,1 | LM-1,2 | LM-1,3 | ... | LM-1, a | ... | LM-1, N-1 | LM-1, N |
| LM, 1 | LM, 2 | LM, 3 | ... | LM, a | ... | LM, N-1 | LM, N |
The coefficient matrix of the screen to be checked of table 4
After above-mentioned calculating process, it is easy to be calculated,
LJ, i=KJ, i*(1/K1, i)=mJ, i*nJ, i*PJ, i*qJ, i*(1/(m1, i*n1, i*p1, i*q1, i))；
The value of wherein m, n, p respectively indicate the illumination intensity non-uniformity coefficient along strip source direction, and camera lens is to light
The Non-uniform responsivity property coefficient of Non-uniform responsivity property coefficient and each pixel of line-scan digital camera.These factors and shooting it is to be checked
The position that do not go together in screen image prime matrix is unrelated, i.e. mJ, i=m1, i, nJ, i=n1, i, PJ, i=p1, i, therefore above formula passes through abbreviation
It is available afterwards
LJ, i=qJ, i/q1, i；
Wherein, qJ, iThe pixel arranged for jth row i-th in screen image prime matrix to be checked is to the reflection inhomogeneities coefficient of light.
In fact, the screen to be checked of plant produced, every a line only has a small number of pixel existing defects, i.e., most of pixels
QJ, iValue be 1, inhomogeneities is embodied in the q of a few pixels pointJ, iValue is not equal to 1.And between not going together, these qJ, iValue is not
Distribution equal to 1 pixel is random.Since every a line of the screen picture to be checked of shooting is all the shooting knot by the first row
Fruit carries out flat field correction, therefore the defect of the first row ith pixel point will be shown in the ith pixel of every a line.I.e.
Can all there be q in the correction coefficient of every a line in same row (i is identical)1, iPresence.
5th step analyzes the coefficient table of acquirement by column, as a certain coefficient L shown more than 90%J, iValue one
It causes, i.e. L1, i=LJ, iWhen, that is, show column (the i-th column) the screen reflective homogeneous property coefficient to be checked of pixel where coefficient the first row
q1, i=1/L1, i.If a certain column coefficient LJ, iThe consistent probability of value be no more than 90%, then it is assumed that this block screen is off quality,
Defect is very more, needs to change one piece of screen to be checked and retests since the first step.
Aforesaid operations are all successively carried out to each column of picture element matrix, finally obtain the pixel response that picture element matrix all arranges
Inhomogeneities coefficient.In the present embodiment, the effective flat field correction coefficient finally obtained is 1/k1i*q1,i, i.e. 1/k1,i*1/L1,i。
When subsequent picture (picture element matrix) for shooting screen to be checked every time, for the gray scale of the pixel of every a line in the picture element matrix of acquisition
Value is multiplied by (1/k1,i*1/L1,i) it can be obtained the true picture after flat field correction effect.
In fact, in the embodiment of technical solution of the present invention, after the effective flat field correction coefficient for obtaining line-scan digital camera,
When continuing shooting using the line-scan digital camera, the every shooting a line picture of line-scan digital camera carries out the gray value that shooting obtains
Correction can be obtained accurate true picture until completing last line picture and after completing correction, that is, line-scan digital camera
Shooting is synchronous progress with correction, to save time cost.It should also be noted that flat using line-scan digital camera in embodiment
The method of field correction can also recycle its effective flat field correction coefficient to bat after line-scan digital camera completes whole shooting tasks
The original image for taking the photograph acquisition is corrected.Both the above process, all within the protection scope of technical solution of the present invention.
As it will be easily appreciated by one skilled in the art that the foregoing is merely illustrative of the preferred embodiments of the present invention, not to
The limitation present invention, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should all include
Within protection scope of the present invention.
Claims (10)
1. a kind of line-scan digital camera method for correcting flat field suitable for field working conditions, which is characterized in that
S1 obtains the initial gray value matrix of screen image prime matrix arbitrary initial row to be checked using line-scan digital camera shooting, at the beginning of described
Beginning gray-value image matrix image obtains original calibration coefficient matrix；
S2 at the uniform velocity moves screen to be checked, the gray-value image of line-scan digital camera scanning shoot screen to be checked, according to on-screen pixels coordinate to be checked
Position distribution obtain the original gradation value matrix of screen to be checked；
S3 is corresponding multiplied by corresponding in the original calibration coefficient matrix by the gray value of every a line in the original gradation value matrix
The original calibration coefficient of column obtains the gray scale value matrix of preliminary corrections；
Median by each grey scale pixel value in the gray scale value matrix of preliminary corrections divided by the row is obtained coefficient by S4
Matrix is simultaneously analyzed, and determines the imaging inhomogeneities coefficient of initial row in screen image prime matrix to be checked；
S5 is corresponding with the column original according to the pixel response nonuniformity property coefficient for being often listed in initial row in screen image prime matrix to be checked
Correction coefficient obtains effective flat field correction coefficient of line-scan digital camera, is corrected to the gray-value image of line-scan digital camera shooting.
2. a kind of line-scan digital camera method for correcting flat field suitable for field working conditions according to claim 1, wherein the step
Include in rapid S1,
S11 obtains the initial gray value matrix of screen image prime matrix initial row to be checked using line-scan digital camera shooting, determines described initial
The median of each pixel coordinate gray value in gray scale value matrix；
It is initial to obtain screen to be checked successively by the gray value of each pixel in the row initial gray value matrix divided by median by S12
Pixel coefficient of the pixel of other coordinates with respect to median in capable initial gray image；
S13 is sequentially inverted to the pixel coefficient according to pixel coordinate in initial gray image, obtains the original of screen each column to be checked
Beginning correction coefficient constitutes original calibration coefficient matrix.
3. a kind of line-scan digital camera method for correcting flat field suitable for field working conditions according to claim 1 or 2, wherein institute
Stating step S4 includes,
S41 is analyzed by the gray scale value matrix of preliminary corrections, obtains the median of every a line gray value in matrix；
The gray value of each row of gray scale value matrix successively divided by the median of the row, is obtained coefficient matrix by S42；
S41 analyzes the coefficient matrix by column, compares the size of each column coefficient；
If there is no less than 90% coefficient value equal with the coefficient value of the column coefficient initial row in the S42 column coefficient, it is determined that should
The pixel response nonuniformity property coefficient of column coefficient initial row corresponding position is the inverse of the coefficient value of the column coefficient initial row；
S43 obtains the pixel response nonuniformity property coefficient of each column of coefficient matrix, constitutes the pixel response nonuniformity of line-scan digital camera
Property coefficient matrix.
4. described in any item a kind of line-scan digital camera method for correcting flat field suitable for field working conditions according to claim 1~3,
In, the step S5 includes,
S51 determines that effective flat field correction coefficient of line-scan digital camera is the pixel response nonuniformity property coefficient of each column initial row multiplied by this
Arrange corresponding original calibration coefficient；
S52 shoots the gray-value image of screen to be checked using line-scan digital camera, and the gray value of each column pixel is corresponding effectively multiplied by the column
Flat field correction coefficient obtains corrected true picture.
5. a kind of line-scan digital camera method for correcting flat field suitable for field working conditions according to any one of claims 1 to 4,
In, the initial gray value matrix of the screen image prime matrix arbitrary initial row to be checked is preferably the first of screen image prime matrix the first row to be checked
Beginning gray scale value matrix.
6. described in any item a kind of line-scan digital camera method for correcting flat field suitable for field working conditions according to claim 1~5,
In, screen to be checked is preferably disposed on transmission microscope carrier in the step S2, and transmission microscope carrier is at the uniform velocity mobile to drive screen to be checked at the uniform velocity to move.
7. described in any item a kind of line-scan digital camera method for correcting flat field suitable for field working conditions according to claim 1~6,
In, the row, column number difference of the screen image prime matrix to be checked, original gradation value matrix and coefficient matrix is equal.
8. according to a kind of described in any item line-scan digital camera method for correcting flat field suitable for field working conditions of claim 2~7,
In, the pixel coefficient k preferably has following calculation formula,
K=m*n*p*q；
Wherein, m is the illumination intensity non-uniformity coefficient along strip source direction；N is camera lens to light Non-uniform responsivity system
Number；P is the Non-uniform responsivity property coefficient of each pixel of line-scan digital camera, and q is reflection inhomogeneities of the screen image vegetarian refreshments to be checked to light
Coefficient.
9. a kind of line-scan digital camera method for correcting flat field suitable for field working conditions according to claim 8, wherein it is described to
It examines screen image vegetarian refreshments and 1 is preferably equal in pixel zero defect to the reflection inhomogeneities coefficient of light, 1 is not equal to when defective.
10. according to a kind of described in any item line-scan digital camera method for correcting flat field suitable for field working conditions of claim 3~9,
Wherein, the coefficient L of each pixel in the coefficient matrixj,iIt is preferred that there is following calculation formula:
Lj,i=qj,i/q1,i；
Wherein, qj,iThe pixel arranged for jth row i-th on screen to be checked is to the reflection inhomogeneities coefficient of light.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810720139.1A CN108986170B (en) | 2018-07-03 | 2018-07-03 | Linear array camera flat field correction method suitable for field working conditions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810720139.1A CN108986170B (en) | 2018-07-03 | 2018-07-03 | Linear array camera flat field correction method suitable for field working conditions |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108986170A true CN108986170A (en) | 2018-12-11 |
| CN108986170B CN108986170B (en) | 2020-11-06 |
Family
ID=64536018
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810720139.1A Active CN108986170B (en) | 2018-07-03 | 2018-07-03 | Linear array camera flat field correction method suitable for field working conditions |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108986170B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109708584A (en) * | 2018-12-30 | 2019-05-03 | 南京航空航天大学 | A kind of oil film interferometry fringe spacing image-recognizing method |
| CN114757853A (en) * | 2022-06-13 | 2022-07-15 | 武汉精立电子技术有限公司 | Flat field correction function acquisition method and system and flat field correction method and system |
| CN116029938A (en) * | 2023-02-24 | 2023-04-28 | 浙江双元科技股份有限公司 | Image flat field correction method and device based on linear fitting |
| CN116634285A (en) * | 2023-04-25 | 2023-08-22 | 钛玛科（北京）工业科技有限公司 | Automatic white balance method of linear array camera for raw material detection equipment |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130147966A1 (en) * | 2009-02-23 | 2013-06-13 | Flir System, Inc. | Flat field correction for infrared cameras |
| CN105701809A (en) * | 2016-01-11 | 2016-06-22 | 宁波江丰生物信息技术有限公司 | Flat-field correction method based on line-scan digital camera scanning |
| CN106780388A (en) * | 2016-12-22 | 2017-05-31 | 哈尔滨工业大学 | A kind of line-scan digital camera optical distortion antidote |
| CN107197122A (en) * | 2017-06-12 | 2017-09-22 | 武汉中导光电设备有限公司 | A kind of method for correcting flat field being imaged for area array cameras |
| CN107194972A (en) * | 2017-05-16 | 2017-09-22 | 成都通甲优博科技有限责任公司 | A kind of camera marking method and system |
-
2018
- 2018-07-03 CN CN201810720139.1A patent/CN108986170B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130147966A1 (en) * | 2009-02-23 | 2013-06-13 | Flir System, Inc. | Flat field correction for infrared cameras |
| CN105701809A (en) * | 2016-01-11 | 2016-06-22 | 宁波江丰生物信息技术有限公司 | Flat-field correction method based on line-scan digital camera scanning |
| CN106780388A (en) * | 2016-12-22 | 2017-05-31 | 哈尔滨工业大学 | A kind of line-scan digital camera optical distortion antidote |
| CN107194972A (en) * | 2017-05-16 | 2017-09-22 | 成都通甲优博科技有限责任公司 | A kind of camera marking method and system |
| CN107197122A (en) * | 2017-06-12 | 2017-09-22 | 武汉中导光电设备有限公司 | A kind of method for correcting flat field being imaged for area array cameras |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109708584A (en) * | 2018-12-30 | 2019-05-03 | 南京航空航天大学 | A kind of oil film interferometry fringe spacing image-recognizing method |
| CN109708584B (en) * | 2018-12-30 | 2020-07-28 | 南京航空航天大学 | Oil film interference method fringe spacing image identification method |
| CN114757853A (en) * | 2022-06-13 | 2022-07-15 | 武汉精立电子技术有限公司 | Flat field correction function acquisition method and system and flat field correction method and system |
| CN114757853B (en) * | 2022-06-13 | 2022-09-09 | 武汉精立电子技术有限公司 | Method and system for acquiring flat field correction function and flat field correction method and system |
| CN116029938A (en) * | 2023-02-24 | 2023-04-28 | 浙江双元科技股份有限公司 | Image flat field correction method and device based on linear fitting |
| CN116029938B (en) * | 2023-02-24 | 2023-06-23 | 浙江双元科技股份有限公司 | Image flat field correction method and device based on linear fitting |
| CN116634285A (en) * | 2023-04-25 | 2023-08-22 | 钛玛科（北京）工业科技有限公司 | Automatic white balance method of linear array camera for raw material detection equipment |
| CN116634285B (en) * | 2023-04-25 | 2024-02-02 | 钛玛科（北京）工业科技有限公司 | Automatic white balance method of linear array camera for raw material detection equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108986170B (en) | 2020-11-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108986170A (en) | A kind of line-scan digital camera method for correcting flat field suitable for field working conditions | |
| US10931924B2 (en) | Method for the generation of a correction model of a camera for the correction of an aberration | |
| CN100367293C (en) | Method and apparatus for optical inspection of a display | |
| US7639372B2 (en) | Scanning system with stereo camera set | |
| KR101949257B1 (en) | Apparatus for Testing Display device module and Method for Testing the same | |
| US20080111989A1 (en) | Transparent material inspection system | |
| CN108760765A (en) | A kind of surface damage defect detecting device and method based on the shooting of side view camera | |
| US20080212076A1 (en) | Apparatus and method for testing infrared camera | |
| CN114323571B (en) | Multi-optical-axis consistency detection method for photoelectric aiming system | |
| KR101630596B1 (en) | Photographing apparatus for bottom of car and operating method thereof | |
| CN105911724B (en) | Determine the method and apparatus of the intensity of illumination for detection and optical detecting method and device | |
| CN110596139A (en) | Screen defect detection method and system | |
| CN104992446B (en) | The image split-joint method of non-linear illumination adaptive and its realize system | |
| CN106840029A (en) | A kind of reflective object surface profiling device high and method | |
| JP2014035261A (en) | Information processing method, information processor, program, imaging apparatus, inspection method, inspection device, and method of manufacturing substrate | |
| CN214097211U (en) | Transparent plate glass's defect detecting device | |
| CN108010071B (en) | System and method for measuring brightness distribution by using 3D depth measurement | |
| JP2007170961A (en) | Inspection device and inspection method | |
| CN106200049A (en) | A kind of picture quality detection method for curved-surface display equipment | |
| CN117092127A (en) | Device and method for detecting upper and lower layer defects of blue light-proof protective film | |
| CN115942127A (en) | Method, device and system for acquiring compensation basic data of display panel and storage medium | |
| JP2012068188A (en) | Adjustment method | |
| CN106933040B (en) | Litho machine splices lighting system and its method of adjustment | |
| JP2011002401A (en) | Correction coefficient calculating method in luminance measuring apparatus, and luminance measuring apparatus | |
| CN110428793B (en) | Brightness correction system and method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |