CN106651810B - Method for correcting image and device, X-ray equipment - Google Patents
Method for correcting image and device, X-ray equipment Download PDFInfo
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Abstract
A kind of method for correcting image and device.Described image bearing calibration includes：The maximum gradation value in each column pixel in the direct exposure area of described image is obtained, determines that the variation tendency of the maximum gradation value of row, the direction arranged in described image are parallel with grid leads direction；The variation tendency of the maximum gradation value arranged in direct exposure area based on described image obtains target gray value；Described image is corrected based on the target gray value.The method for correcting image of technical solution of the present invention, calibration result is good, and the gradation of image after correction is uniform, meets actual clinical demand.
Description
Technical field
The present invention relates to technical field of image processing, more particularly to a kind of method for correcting image and device, X-ray are set
It is standby.
Background technology
Digital X-ray (Digital Radiography, DR) photographic equipment is computer digital image treatment technology and X
Ray irradiation technology is combined and a kind of advanced medical system for being formed.Digital X-ray photographic equipment because its dose of radiation is small,
The quality of image is high, the accuracy of the recall rate of disease and diagnosis is higher and is widely used.
X-ray will produce scattered rays after passing through human body, and then can lead to image blur, reduce the contrast of image,
It is unfavorable for observation and diagnosis of the doctor to lesion, therefore usually eliminates shadow of the scattered rays to image with the grid of anti-scatter
It rings.For DR equipment, every leads of grid is all tilted a certain angle to ray source focus, the elongated surfaces of all leads
It can intersect on straight line, the distance of this straight line to grid surface is the focal length of grid.When ray source focus, filter line
The center three of grid center and detector point-blank (also referred to as DR equipment is in Shaft alignment state), and the source image of DR equipment
When being equal to the focal length of grid away from (SID, Source Image Distance), the quality of DR equipment the image collected is preferable,
However the grid of multiple and different focal lengths can not possibly be equipped with for DR equipment, therefore in practical applications, a grid
It can use within the scope of the different SID allowed in regulation.It (is also referred to as filtered when grid is used at the SID for deviateing focal length
Wiregrating use is in out-of-focus appearance), detector the image collected can be uneven, and the gray scale among image is higher than the gray scale on both sides.
In addition, when grid use is in the case where misaligning, it also will appear image non-uniform phenomenon, and the focus of radiographic source,
Grid center and the center of detector are it is difficult to ensure that point-blank.When grid use defocus and Shaft alignment state not
When in the case of very good, the non-uniform phenomenon of image can aggravate.Therefore it needs according to the attenuation of grid come to collecting
Image be corrected.
The prior art usually obtains the correction coefficient of the grid under different SID by acquiring non-loaded image, then
Using corresponding correction coefficient at the SID the image collected be corrected.But the situation of DR equipment in actual use
Situation with DR equipment when obtaining grid correction coefficient may be inconsistent, as SID can be after a period of use for DR equipment
Deviation etc., in addition actually use in DR equipment centering also have must difficulty, therefore using existing way correction after, finally
Correction expected effect is not achieved.
Therefore, how the image collected is corrected, is in out-of-focus appearance and/or DR equipment with eliminating grid
The influence brought in the case of non-centering obtains the image for uniformly meeting actual clinical demand, becomes urgently to be resolved hurrily at present and asks
One of topic.
Invention content
The problem to be solved in the present invention is to provide a kind of method for correcting image, so that the gradation of image after being corrected is equal
Even, quality meets actual clinical demand.
To solve the above problems, technical solution of the present invention provides a kind of method for correcting image, including：
The maximum gradation value in each column pixel in the direct exposure area of described image is obtained, determines the maximum gray scale of row
The variation tendency of value, the direction arranged in described image are parallel with grid leads direction；
The variation tendency of the maximum gradation value arranged in direct exposure area based on described image obtains target gray value；
Described image is corrected based on the target gray value.
Optionally, the maximum gradation value in the direct exposure area for obtaining described image in each column pixel includes：
Obtain the maximum gradation value in each column pixel in described image；
It is more than the region where the image column of default gray value with the maximum gradation value in each column pixel in described image
For direct exposure area；The default gray value is associated with the maximum gradation value of described image.
Optionally, the variation tendency of the maximum gradation value arranged in the direct exposure area of described image is determined, including：
Be less than with the maximum gradation value in each column pixel in described image the image column of default gray value row coordinate and
Maximum gradation value under the row coordinate in corresponding row pixel determines the first data point；
Choose initial segmentation point, with pre- fixed step size update the initial segmentation point until updated cut-point row coordinate
Not less than default row coordinate, the default row coordinate is associated with the maximum column coordinate of described image；
It is less than the first of the row coordinate of each cut-point obtained in the initial segmentation point renewal process to row coordinate
Data point is fitted, to obtain a plurality of first curve；
Corresponding cut-point column coordinate is symmetry axis when to a plurality of first curve using with fitting a plurality of first curve
Generation and its symmetrical a plurality of second curve, are formed a plurality of with a plurality of first curve and corresponding a plurality of second curve
Curve is the first maximum gradation value change curve；
First data point is carried out symmetrically by symmetry axis of central point column coordinate, to obtain the second data point,
The row coordinate of the central point is the half of described image maximum column coordinate；
It is less than the second data of the row coordinate of each cut-point obtained in the cut-point renewal process to row coordinate
Point is fitted, to obtain a plurality of third curve；
Corresponding cut-point column coordinate is symmetry axis when to a plurality of third curve using with the fitting a plurality of third curve
Generation and its symmetrical a plurality of 4th curve, are formed a plurality of with a plurality of third curve and corresponding a plurality of 4th curve
Curve is the second maximum gradation value change curve；
Using the first maximum gradation value change curve and the second maximum gradation value change curve as described image
The variation tendency of the maximum gradation value arranged in direct exposure area.
Optionally, the variation tendency of the maximum gradation value arranged in the direct exposure area based on described image determines mesh
Marking gray value includes：
Determine in the first maximum gradation value change curve with the immediate first maximum gray scale of first data point
Value change curve is first object curve；
Determine in the second maximum gradation value change curve with the immediate second maximum gray scale of second data point
Value change curve is the second aim curve；
When the degree of closeness of the first object curve and first data point is more than second aim curve and institute
When stating the degree of closeness of the second data point, using the first object curve as aim curve；
When the degree of closeness of second aim curve and second data point is more than the first object curve and institute
It is symmetrical with row where the row coordinate of cut-point corresponding with second aim curve when stating the degree of closeness of the first data point
Axisymmetric curve is aim curve；
Determine that corresponding maximum gradation value is target gray value on the aim curve.
Optionally, in the determination the first maximum gradation value change curve with first data point immediate
One maximum gradation value change curve is that first object curve includes：Determine that each row coordinate of first data point is corresponding
Gray value under the row coordinate on the first maximum gradation value change curve the absolute value of the difference of corresponding gray value and for minimum
When the first maximum gradation value change curve be first object curve；
It is maximum with second data point immediate second in determination the second maximum gradation value change curve
Gray-value variation curve is that the second aim curve includes：Determine each corresponding gray value of row coordinate of second data point
With under the row coordinate on the second maximum gradation value change curve the absolute value of the difference of corresponding gray value and for minimum when
Two maximum gradation value change curves are the second aim curve.
Optionally, the first object curve and the degree of closeness of first data point refer to：With first data
Under each corresponding gray value of row coordinate and the row coordinate of point on first object curve the difference of corresponding gray value it is absolute
The sum of value；
Second aim curve and the degree of closeness of second data point refer to：With each of second data point
The corresponding gray value of a row coordinate under the row coordinate on the second aim curve the absolute value of the difference of corresponding gray value and.
Optionally, it is described based on the target gray value to described image be corrected including：By the picture in described image
The gray value of vegetarian refreshments is adjusted to the target gray value.
Optionally, the gray value by the pixel in described image, which is adjusted to the target gray value, includes：
The aim curve is normalized with the target gray value；
Based on normalized aim curve to obtain the correction coefficient of grid；
Described image is multiplied by be corrected to described image with the correction coefficient of the grid.
To solve the above problems, technical solution of the present invention also provides a kind of image correction apparatus, including
Acquiring unit, the maximum gradation value in the direct exposure area for obtaining described image in each column pixel, really
Surely the variation tendency of the maximum gradation value arranged, the direction arranged in described image are parallel with grid leads direction；
Target gray value acquiring unit, the change of the maximum gradation value for being arranged in the direct exposure area based on described image
Change trend obtains target gray value；
Unit is corrected, described image is corrected for being based on the target gray value.
To solve the above problems, technical solution of the present invention also provides a kind of X-ray equipment, including above-mentioned image calibration
Equipment.
Compared with prior art, technical solution of the present invention has the following advantages：
The maximum gradation value of the row parallel with grid leads direction in direct exposure area by obtaining image
Variation tendency to obtain target gray value, and then described image is corrected based on the target gray value.Due to basis
The actual conditions of the image collected are corrected, rather than the grid correction coefficient to obtain under conditions of pre-set
It is corrected, therefore avoids actual conditions and to preset calibration result caused by condition has deviation poor, after correction
Image does not meet the phenomenon that actual clinical demand still, while simplifying aligning step, but also the correction finally obtained
Gradation of image afterwards uniformly meets actual clinical demand, and then is also avoided that and fails to pinpoint a disease in diagnosis or the generation of mistaken diagnosis phenomenon.In addition, with
The variation tendency of the maximum gradation value arranged in the direct exposure area of described image obtains target gray value, avoids and is obtaining
The influence of target area during target gray value, and then when being corrected to image with the target gray value, Neng Gougeng
Good elimination improves calibration result, correction due to the influence that grid be in out-of-focus appearance and/or when equipment misaligns brings
The gray value of image afterwards is uniform, can reach expected effect.
Further, in the direct exposure area for obtaining described image when maximum gradation value in each column pixel, with
Region where maximum gradation value in described image in each column pixel is more than the image column of default gray value is directly to expose
Region.The maximum gradation value obtained in direct exposure area in each column pixel is realized in a simpler way.Additionally, due to
Direct exposure area in described image need not be detected, therefore simplify the direct exposure area for obtaining described image
The process of maximum gradation value in middle each column pixel, and then the step of also simplifying correction, improve school to a certain extent
Positive speed.
Further, the variation tendency of the maximum gradation value arranged in the direct exposure area based on described image determines mesh
When marking gray value, the degree of closeness of the first object curve and first data point be more than second aim curve with
When the degree of closeness of second data point, using the first object curve as aim curve；Second aim curve with
When the degree of closeness of second data point is more than the degree of closeness of the first object curve and first data point, with
The corresponding cut-point column coordinate of second aim curve is that symmetrical axisymmetric curve is aim curve；Pass through this side
The aim curve accuracy that formula obtains is high, and then the accuracy of the target gray value based on aim curve acquisition is also higher, with
When the target gray value is corrected, the picture quality after correction meets actual clinical demand.
Description of the drawings
Fig. 1 is the flow diagram of the method for correcting image of embodiment of the present invention；
Fig. 2 is the schematic diagram of the image collected of the embodiment of the present invention；
Fig. 3 is a plurality of first maximum gradation value change curve and the first data point that the fitting of the embodiment of the present invention obtains
Relation schematic diagram；
Fig. 4 is a plurality of second maximum gradation value change curve and the second data point that the fitting of the embodiment of the present invention obtains
Relation schematic diagram；
Fig. 5 is the schematic diagram of the grid correction coefficient curve of the embodiment of the present invention.
Specific implementation mode
To make the above purposes, features and advantages of the invention more obvious and understandable, below in conjunction with the accompanying drawings to the present invention
Specific implementation mode be described in detail.Detail is elaborated in the following description in order to fully understand the present invention.But
It is the present invention with a variety of to implement different from other manner described here, those skilled in the art can be without prejudice to originally
Various changes are done in the case of invention intension.Therefore the present invention is not limited by following public specific implementation mode.
As described in the prior art, the prior art is not caused in correction by grid defocus and/or system
Gradation of image it is uneven when, acquisition grid correction coefficient need to be shifted to an earlier date under conditions of pre-set, and then pass through the school
Positive coefficient to actual acquisition to image be corrected, since actual conditions and pre-set condition are deviated, cause
Calibration result is bad, and the bearing calibration complex steps.
Therefore, inventor proposes directly to analyze the direct exposure area of the image collected, to obtain grid
Correction coefficient, and then the image collected is corrected according to the correction coefficient, according to actual acquisition to image determine
Calibration result is poor caused by grid correction coefficient, avoidable actual conditions and pre-set condition are not inconsistent, after correction
Gradation of image uniformly and actual clinical demand can be met.
Fig. 1 is referred to, Fig. 1 is the flow diagram of the method for correcting image of embodiment of the present invention, as shown in Figure 1, institute
Stating method for correcting image includes：
S101：The maximum gradation value in each column pixel in the direct exposure area of described image is obtained, determines row most
The variation tendency of high-gray level value, the direction arranged in described image are parallel with grid leads direction；
S102：The variation tendency of the maximum gradation value arranged in direct exposure area based on described image obtains target gray
Value；
S103:Described image is corrected based on the target gray value.
The method for correcting image of embodiment of the present invention is described in detail below in conjunction with specific embodiment.
Those skilled in the art know that grid is generally positioned at before x-ray imaging unit, the x-ray imaging list
Member can be detector, be made of the material with different x-ray fade performance of regular arrangement, to reduce imaging unit receiving
The scattering radiation arrived, so as to improve the contrast of collected radioscopic image.The inside of grid is usually by multiple eight-to-pica leads phases
It mutually arranges, is positioned with easily radiotransparen substance filling between two leads, and be bonded together.Filler can be sawdust,
Paper or aluminium flake etc..In use, non-scatter X-ray can normally pass through grid, and most scattered rays then can be by
Leads absorbs, and only seldom a part of scattered rays can pass through grid to reach x-ray imaging unit.In order to obtain filter line
Each leads is in practical situations to the attenuation degree of X-ray in grid, with flat with the leads direction of grid in the present embodiment
Influence degree of the different leads to imaging unit is obtained on the basis of capable image column.
S101 is executed, the maximum gradation value in each column pixel in the direct exposure area of described image is obtained, determines row
Maximum gradation value variation tendency, the direction arranged in described image is parallel with grid leads direction.
In the present embodiment, the image collected includes direct exposure area and target area, is this hair referring to Fig. 2, Fig. 2
The schematic diagram of the image collected of bright embodiment, white region is direct exposure area in Fig. 2, remaining part is target
Region is herein human region.In the present embodiment, in the direct exposure area that described image is obtained in particular by such as under type
Maximum gradation value in each column pixel：
In view of the gray scale of target area is low, the gray scale of direct exposure area is high, in order to accurately obtain as far as possible
Direct exposure area in described image in the present embodiment, first obtains in described image ash in the gray value of each row pixel
(for Fig. 2, the row in image are along perpendicular for the maximum gradation value of that maximum gray value of angle value namely each row pixel
Histogram to), the region where maximum gradation value is more than the image column of default gray value is then chosen in all image columns is
Direct exposure area obtains the maximum gradation value in each row pixel finally in the direct exposure area having chosen.It is described
Default gray value is related to the maximum gradation value of described image, and the ranging from [0.4G of gray value is preset described in the present embodimentmax,
0.6Gmax], GmaxFor the maximum gradation value of described image.
Next, according to the maximum gradation value in each column pixel in the direct exposure area of the described image of acquisition come really
Surely the maximum gradation value variation tendency arranged.With the row coordinate value in the direct exposure area that obtains through the above way for horizontal seat
It marks, the maximum gradation value in row pixel corresponding with the row coordinate value is that ordinate determines the first data point.Referring to Fig. 3, Fig. 3
In illustrate the first data point, choose initial segmentation point, the row coordinate of the point of initial segmentation described in the present embodiment is associated with described
The maximum column coordinate of image, the row coordinate of the initial segmentation point is ranging fromWherein CmaxFor institute
The maximum column coordinate for stating image, referring to Fig. 3, the maximum column coordinate of image shown in Fig. 3 is 3000, the initial segmentation point
Row coordinate can be 1500, update the initial segmentation point with pre- fixed step size, and often update once can all obtain a cut-point, directly
The row coordinate of the cut-point obtained to final updating is not less than default row coordinate, and presetting row coordinate described in the present embodiment can be
Cmax, the pre- fixed step size, default row coordinate can be depending on actual demands.The pre- fixed step size can be 100 pixels
Point, namely the initial segmentation o'clock is updated with 100 step-length, to obtain cut-point 1600,1700 ... 3000.It is obtaining
After obtaining a series of cut-point, the first data point that the row coordinate of each cut-point is less than for row coordinate is fitted, can
To obtain a plurality of first curve, linear fit is used in the present embodiment, as shown in Figure 3, and in fit procedure, often to be less than
As soon as the first data point fitting of the row coordinate of cut-point is primary, using the row where the row coordinate using the cut-point as symmetry axis
The second curve with the first curve symmetric is generated, cut-point often updates once, will fit first curve, accordingly
It is symmetrical axisymmetric second curve with the row coordinate of cut-point that one, which can be generated, with the first curve, and the first curve and second is bent
Line combines (the first curve and the second curve intersection) to obtain the first maximum gradation value curve, is then obtained with the update of cut-point
A plurality of first maximum gradation value curve.
Accuracy in order to ensure the aim curve finally obtained is higher, to first data point with central point column
Coordinate is that symmetry axis carries out symmetrically, and to obtain the second data point, the row coordinate of the central point is described image maximum column coordinate
Half.Referring to Fig. 4, the second data point shown in Fig. 4 is that the first data point shown in Fig. 3 is sat with the row of central point
It is classified as what symmetry axis symmetrically obtained where mark (row coordinate is 1500), is updated less than the cut-point similarly, for row coordinate
Second data point of the row coordinate of each cut-point obtained in the process is fitted, and referring to Fig. 4, is with initial segmentation point
For 1500, then it is less than 1500 the second data point linear fit to row coordinate, to obtain third curve, with the row where 1500
It is symmetrical axial symmetry to obtain the 4th curve, the variation of the second maximum gradation value is combined as with the third curve and the 4th curve
Curve.It is exactly the second data point for being less than 1600 to row coordinate if updating initial segmentation point with step-length 100 to obtain cut-point
Linear fit is symmetrical axial symmetry to obtain the 4th curve with the row where 1600, with what is obtained at this time to obtain third curve
The third curve and the 4th curve are combined as the second maximum gradation value conversion curve.And so on, a plurality of can be obtained
Two maximum gradation value change curves.
The the first maximum gradation value change curve and the second maximum gradation value change curve of above-mentioned acquisition are then described image
Direct exposure area in the variation tendency of maximum gradation value that arranges.It is arranged in the direct exposure area for obtaining described image
After maximum gradation value variation tendency, i.e., a plurality of first maximum gradation value change curve and a plurality of second maximum gradation value change curve
Afterwards, S102 is executed, mesh is obtained with a plurality of first maximum gradation value change curve and a plurality of second maximum gradation value change curve
Mark gray value.In the present embodiment, specifically：
It first determines maximum grey with first data point immediate first in the first maximum gradation value change curve
Angle value change curve is first object curve, namely determines which item the first maximum gradation value change curve and the first number in Fig. 3
Strong point is closest.It is sat with the row in the present embodiment by calculating each corresponding gray value of row coordinate of first data point
On the lower first maximum gradation value change curve of mark the absolute value of the difference of corresponding gray value and to weigh the first maximum gradation value
The degree of closeness of change curve and the first data point.When between a certain item the first maximum gradation value change curve and the first data point
When the absolute value of the difference of the gray value of corresponding points (the identical point of row coordinate) and minimum, the first maximum gradation value change curve
For first object curve.
Similarly, it determines in the second maximum gradation value change curve with second data point immediate second most
When high-gray level value change curve is the second aim curve, a second maximum gradation value change curve is exactly found, with second
Between data point the absolute value of the difference of the gray value of corresponding points (the identical point of row coordinate) and minimum, second maximum gradation value
Change curve is the second aim curve.
The exhausted of the difference of the gray value of corresponding points between first object curve and the first data point is obtained by the above process
To value and S1, which characterizes the degrees of closeness between first object curve and the first data point, similarly also obtain second
Between aim curve and the second data point the absolute value of the difference of the gray value of corresponding points and S2, also characterize the second target song
Degree of closeness between line and the second data point, if S1<S2Then using the first object curve as aim curve；If S2<S1, then
The row using where the row coordinate of corresponding cut-point when obtaining second aim curve are the symmetrical curve of symmetry axis as target song
Line, for example, the second aim curve be with 1600 be what cut-point obtained, then be symmetry axis by described the with row where 1600
Two aim curves carry out symmetrically to obtain aim curve.
So far, aim curve is obtained through the above way, and corresponding maximum gradation value is mesh on the aim curve
Mark gray value.
When practical application, it can be realized by way of array and be arranged most in the direct exposure area of determining described image
The variation tendency and aim curve of high-gray level value, specifically：
First, using the maximum gradation value in each column pixel in described image as the first array of Element generation, described first
It is also right that the maximum gradation value in each column pixel, each gray value in target area and direct exposure area are contained in array
Answer a row coordinate.
Then, the value that gray value in first array is less than to the element of default gray value is set to zero to generate the second number
Group, the nonzero element in second array be described image direct exposure area in maximum gray scale in each column pixel
Value.With in second array nonzero element and row coordinate corresponding with the nonzero element come determine the first data point (directly
Data point determined by the row coordinate of image column maximum gradation value corresponding with the row coordinate in exposure area).
Similarly, initial segmentation point is chosen, for 1500 in Fig. 3, to row coordinate in the second array less than 1500
First data point is fitted, and obtains the first curve, and is that symmetrical axial symmetry obtains the second curve with the row where 1500, and first
Curve and the second curve constitute the first maximum gradation value change curve.With 1600 for cut-point to row coordinate less than 1600 the
One data point carries out linear fit, obtains the first curve corresponding with the cut-point and the second curve, namely obtains and this point
The corresponding first maximum gradation value change curve of cutpoint.The rest may be inferred, obtains a plurality of first maximum gradation value change curve.It is right
Element in second array by row coordinate be 1500 when corresponding element centered on point carry out symmetrical obtaining third array, third number
The row coordinate that each gray value is corresponding in group forms the second data point.Similarly, with 1500 for initial segmentation point, to the
Row make second data point progress linear fit of the mark less than 1500 in three arrays, obtain third curve, and with the row where 1500
The 4th curve is obtained for symmetrical axial symmetry, third curve and the 4th curve constitute the second maximum gradation value change curve.With
1600 the second data point for cut-point to row coordinate less than 1600 carries out linear fit, obtains third corresponding with the cut-point
Curve and the 4th curve, namely obtain the second maximum gradation value change curve corresponding with the cut-point.The rest may be inferred, obtains
A plurality of second maximum gradation value change curve.
It determines bent for first object with the immediate curve of the first data point in a plurality of first maximum gradation value change curve
Line with the immediate curve of the second data point is the second aim curve in a plurality of second maximum gradation value change curve, how root
Same as described above according to first object curve and the second aim curve acquisition aim curve, details are not described herein again.
S103 is executed, described image is corrected based on the target gray value, is exactly by the figure in the present embodiment
The gray value of pixel as in is adjusted to the target gray value, specifically：
The aim curve is normalized with the target gray value first to obtain the correction coefficient of grid, it is right
The aim curve is normalized, and is exactly to be kept to the abscissa (coordinate for indicating image column) of corresponding point on aim curve
It is constant, ordinate (illustrating corresponding maximum gradation value under image column coordinate) divided by target gray value.Lead in the present embodiment
Cross the correction coefficient that following formula obtains grid：
Wherein, x is row coordinate, the G of imagegoalIt is target gray value, Lgoal(x) it is aim curve.
After obtaining grid correction coefficient through the above way, then it can lead to the correction coefficient and school is carried out to described image
Just.It is the schematic diagram of the grid correction coefficient curve of the embodiment of the present invention referring to Fig. 5, Fig. 5.It, can be in practical application
The grid correction coefficient curve of acquisition is filtered, so that the grid calibration curve is smoother, filters out grid
Noise spot that may be present in correction coefficient curve.
After obtaining grid correction coefficient, the gray value of described image is carried out by following formula in the present embodiment
Correction：
Wherein, x is the row coordinate of image, and OriginalData (x) is the gray scale for the pixel that row coordinate is x in image
Value, B (x) be grid correction coefficient, CorrectedData (x) be correct after image in row coordinate be x pixel ash
Angle value.
So far, it by the grid correction coefficient of acquisition in the present embodiment, realizes the ash of each column pixel in image
The corrected purpose of angle value, the gradation of image after correction is uniform, meets actual clinical demand.
Corresponding above-mentioned method for correcting image, embodiment of the present invention also provide a kind of image correction apparatus, described image
Means for correcting includes：
Acquiring unit, the maximum gradation value in the direct exposure area for obtaining described image in each column pixel, really
Surely the variation tendency of the maximum gradation value arranged, the direction arranged in described image are parallel with grid leads direction；
Target gray value acquiring unit, the change of the maximum gradation value for being arranged in the direct exposure area based on described image
Change trend obtains target gray value；
Unit is corrected, described image is corrected for being based on the target gray value.
The implementation of described image means for correcting may refer to the implementation of above-mentioned method for correcting image, and details are not described herein again.
The embodiment of the present invention also provides a kind of X-ray equipment, including above-mentioned image correction apparatus.
In conclusion method for correcting image and device that embodiment of the present invention provides, at least have the advantages that：
The maximum gradation value of the row parallel with grid leads direction in direct exposure area by obtaining image
Variation tendency to obtain target gray value, and then described image is corrected based on the target gray value.Due to basis
The actual conditions of the image collected are corrected, rather than the grid correction coefficient to obtain under conditions of pre-set
It is corrected, therefore avoids actual conditions and to preset calibration result caused by condition has deviation poor, after correction
Image does not meet the phenomenon that actual clinical demand still, while simplifying aligning step, but also the correction finally obtained
Gradation of image afterwards uniformly meets actual clinical demand, and then is also avoided that and fails to pinpoint a disease in diagnosis or the generation of mistaken diagnosis phenomenon.In addition, with
The variation tendency of the maximum gradation value arranged in the direct exposure area of described image obtains target gray value, avoids and is obtaining
The influence of target area during target gray value, and then when being corrected to image with the target gray value, Neng Gougeng
Good elimination improves calibration result, correction due to the influence that grid be in out-of-focus appearance and/or when equipment misaligns brings
The gray value of image afterwards is uniform, can reach expected effect.
Further, in the direct exposure area for obtaining described image when maximum gradation value in each column pixel, with
Region where maximum gradation value in described image in each column pixel is more than the image column of default gray value is directly to expose
Region.The maximum gradation value obtained in direct exposure area in each column pixel is realized in a simpler way.Additionally, due to
Direct exposure area in described image need not be detected, therefore simplify the direct exposure area for obtaining described image
The process of maximum gradation value in middle each column pixel, and then the step of also simplifying correction, improve school to a certain extent
Positive speed.
Further, the variation tendency of the maximum gradation value arranged in the direct exposure area based on described image determines mesh
When marking gray value, the degree of closeness of the first object curve and first data point be more than second aim curve with
When the degree of closeness of second data point, using the first object curve as aim curve；Second aim curve with
When the degree of closeness of second data point is more than the degree of closeness of the first object curve and first data point, with
The corresponding cut-point column coordinate of second aim curve is that symmetrical axisymmetric curve is aim curve；Pass through this side
The aim curve accuracy that formula obtains is high, and then the accuracy of the target gray value based on aim curve acquisition is also higher, with
When the target gray value is corrected, the picture quality after correction meets actual clinical demand.
Although the invention has been described by way of example and in terms of the preferred embodiments, but it is not for limiting the present invention, any this field
Technical staff without departing from the spirit and scope of the present invention, may be by the methods and technical content of the disclosure above to this hair
Bright technical solution makes possible variation and modification, therefore, every content without departing from technical solution of the present invention, and according to the present invention
Technical spirit to any simple modifications, equivalents, and modifications made by above example, belong to technical solution of the present invention
Protection domain.
Claims (10)
1. a kind of method for correcting image, which is characterized in that including：
The maximum gradation value in each column pixel in the direct exposure area of described image is obtained, determines the maximum gradation value of row
Variation tendency, the direction arranged in described image are parallel with grid leads direction；
The variation tendency of the maximum gradation value arranged in direct exposure area based on described image obtains target gray value；
Described image is corrected based on the target gray value.
2. method for correcting image as described in claim 1, which is characterized in that the direct exposure area for obtaining described image
Maximum gradation value in middle each column pixel includes：
Obtain the maximum gradation value in each column pixel in described image；
Region where being more than the image column of default gray value with the maximum gradation value in each column pixel in described image is straight
Connect exposure area；The default gray value is associated with the maximum gradation value of described image.
3. method for correcting image as claimed in claim 2, which is characterized in that determine and arranged in the direct exposure area of described image
Maximum gradation value variation tendency, including：
It is less than the row coordinate and the row of the image column of default gray value with the maximum gradation value in each column pixel in described image
Maximum gradation value under coordinate in corresponding row pixel determines the first data point；
Initial segmentation point is chosen, the initial segmentation point is updated with pre- fixed step size until the row coordinate of updated cut-point is not small
In default row coordinate, the default row coordinate is associated with the maximum column coordinate of described image；
It is less than the first data of the row coordinate of each cut-point obtained in the initial segmentation point renewal process to row coordinate
Point is fitted, to obtain a plurality of first curve；
A plurality of first curve is generated using cut-point column coordinate corresponding with when being fitted a plurality of first curve as symmetry axis
With a plurality of second curve of a plurality of first curve symmetric, with a plurality of first curve and corresponding a plurality of second curve institute
The a plurality of curve of composition is the first maximum gradation value change curve；
First data point is carried out symmetrically by symmetry axis of central point column coordinate, it is described to obtain the second data point
The row coordinate of central point is the half of described image maximum column coordinate；
The second data for being less than the row coordinate of each cut-point obtained in the cut-point renewal process to row coordinate click through
Row fitting, to obtain a plurality of third curve；
A plurality of third curve is generated using cut-point column coordinate corresponding with when being fitted a plurality of third curve as symmetry axis
With a plurality of 4th curve of a plurality of third curve symmetric, with a plurality of third curve and corresponding a plurality of 4th curve institute
The a plurality of curve of composition is the second maximum gradation value change curve；
Using the first maximum gradation value change curve and the second maximum gradation value change curve as the direct of described image
The variation tendency of the maximum gradation value arranged in exposure area.
4. method for correcting image as claimed in claim 3, which is characterized in that the direct exposure area based on described image
The variation tendency of the maximum gradation value of middle row obtains target gray value：
It determines in the first maximum gradation value change curve and becomes with immediate first maximum gradation value of first data point
Change curve is first object curve；
It determines in the second maximum gradation value change curve and becomes with immediate second maximum gradation value of second data point
Change curve is the second aim curve；
When the degree of closeness of the first object curve and first data point is more than second aim curve and described the
When the degree of closeness of two data points, using the first object curve as aim curve；
When the degree of closeness of second aim curve and second data point is more than the first object curve and described the
When the degree of closeness of one data point, with row where the row coordinate of cut-point corresponding with second aim curve for symmetry axis pair
Curve be referred to as aim curve；
Determine that corresponding maximum gradation value is target gray value on the aim curve.
5. method for correcting image as claimed in claim 4, which is characterized in that determination the first maximum gradation value variation
Include for first object curve with the immediate first maximum gradation value change curve of first data point in curve：Determine institute
State each corresponding gray value of row coordinate of the first data point under the row coordinate on the first maximum gradation value change curve it is right
The absolute value of the difference for the gray value answered and for minimum when the first maximum gradation value change curve be first object curve；
In determination the second maximum gradation value change curve with the immediate second maximum gray scale of second data point
Value change curve is that the second aim curve includes：It determines each corresponding gray value of row coordinate of second data point and is somebody's turn to do
Under row coordinate on the second maximum gradation value change curve the absolute value of the difference of corresponding gray value and for minimum when second most
High-gray level value change curve is the second aim curve.
6. method for correcting image as claimed in claim 5, which is characterized in that
The first object curve and the degree of closeness of first data point refer to：With each row of first data point
The corresponding gray value of coordinate under the row coordinate on first object curve the absolute value of the difference of corresponding gray value and；
Second aim curve and the degree of closeness of second data point refer to：With each row of second data point
The corresponding gray value of coordinate under the row coordinate on the second aim curve the absolute value of the difference of corresponding gray value and.
7. method for correcting image as claimed in claim 6, which is characterized in that described to be based on the target gray value to the figure
As be corrected including：The gray value of pixel in described image is adjusted to the target gray value.
8. method for correcting image as claimed in claim 6, which is characterized in that the gray scale by the pixel in described image
Value is adjusted to the target gray value：
The aim curve is normalized with the target gray value；
Based on normalized aim curve to obtain the correction coefficient of grid；
Described image is multiplied by be corrected to described image with the correction coefficient of the grid.
9. a kind of image correction apparatus, which is characterized in that including：
Acquiring unit, the maximum gradation value in the direct exposure area for obtaining described image in each column pixel determine row
Maximum gradation value variation tendency, the direction arranged in described image is parallel with grid leads direction；
The variation of target gray value acquiring unit, the maximum gradation value for being arranged in the direct exposure area based on described image becomes
Gesture obtains target gray value；
Unit is corrected, described image is corrected for being based on the target gray value.
10. a kind of X-ray equipment, which is characterized in that including the image correction apparatus described in claim 9.
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| CN1720860A (en) * | 2004-06-03 | 2006-01-18 | 西门子公司 | Method for compensating image interference in radiation photograph |
| CN102411775A (en) * | 2011-08-10 | 2012-04-11 | Tcl集团股份有限公司 | Method and system for correcting brightness of text image |
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| CN101482971B (en) * | 2009-02-23 | 2011-08-17 | 公安部第一研究所 | Non-uniform correction method for compensation of low-gray scale X-ray image signal |
| CN103489156B (en) * | 2012-06-09 | 2016-08-17 | 北京国药恒瑞美联信息技术有限公司 | A kind of processing method of digital X-ray |
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| CN1720860A (en) * | 2004-06-03 | 2006-01-18 | 西门子公司 | Method for compensating image interference in radiation photograph |
| CN102411775A (en) * | 2011-08-10 | 2012-04-11 | Tcl集团股份有限公司 | Method and system for correcting brightness of text image |
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Address after: 201807 No. 2258 Chengbei Road, Jiading Industrial Zone, Jiading District, Shanghai. Patentee after: Shanghai Lianying Medical Technology Co., Ltd Address before: 201807 No. 2258 Chengbei Road, Jiading Industrial Zone, Jiading District, Shanghai. Patentee before: SHANGHAI UNITED IMAGING HEALTHCARE Co.,Ltd. |