CN103458194B - Method and device for analyzing exposure degree of digital image and video and digital imaging system - Google Patents
Method and device for analyzing exposure degree of digital image and video and digital imaging system Download PDFInfo
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Abstract
The invention discloses a method and device for analyzing the exposure degree of a digital image and video and a digital imaging system, so that accurate exposure parameters are provided for an imaging device, and an image and video with good quality is obtained. The method comprises the steps of converting the digital image and video into a grey level image and video if the format of the obtained digital image and video is not grey level; conducting histogram statistic on the grey level image and video to obtain a grey level histogram of the grey level image and video; analyzing the pixel brightness of the grey level digital image and video according to the grey level histogram to output an exposure degree value of the digital image and video. The exposure degree analyzing method is simple, fast and convenient, is applied to an imaging system similar to a digital camera and can help the imaging system to adjust the exposure parameters, and a user conveniently adjusts the exposure parameters for re-shooting. When the method is applied to image management and processing software, the method can help the user to select the image and video, and the parameters are adjusted and compensated in a post exposure compensation program.
Description
Technical field
The present invention relates to image processing field is and in particular to analyze the method for digital image exposure degree, device and one kind
Digital imaging system.
Background technology
In existing digital imaging system, great majority are all that ambient light is carried out with light-metering, calculate the ambient light in each region
Intensity, then, then the intensity of the ambient light in each region is weighted, to obtain exposure parameter.Due to answering of environment
Polygamy, said method still occurs in that a lot of scene exposure parameter setting mistakes, leads to captured digital photograph substantially to expose
Mistake, thus cause damage.
In digital imaging management application, automatic decision image exposure has important using value it can be determined that going out shadow
Seem that no exposure is accurate, thus picking out vicious photo.In most software, such as Photoshop, nEO iMAGING
Deng in image processing software, all carry exposure compensating function, the exposure of exposed image can be compensated.Based on above-mentioned image
Process the exposure compensating function that has of software, a kind of be weighted acquisition exposure with respect to above by light-metering and to light intensity
The method that parameter improves to some extent is to carry out light-metering before shooting, arranges exposure parameter, after the picture is taken, is judged by human eye subjectivity
Whether photo exposes accurately.If exposure is inaccurate, carry out the process of post-exposure compensation, example using image processing software
As compensated to the image of deficient exposure and overexposure and correcting, to obtaining the preferable image of exposure effect.
However, image processing software logarithmic code image whether overexposure and/or owe to expose and be unaware of itself.Digital image overexposure
Deficient whether expose there is still a need for naked eyes judged, so, can be by the image error handle of Correct exposure.On the other hand, digital phase
Machine and video camera great majority all possess image preview function, that is,：A liquid crystal display is provided to show shooting picture, equipment before shooting
Automatically carry out judging exposure parameter, the exposure parameter of mistake so, can be obtained because of environment reason, cause shadow under preview mode
Owe to expose or overexposure as showing in liquid crystal display.
Analysis more than synthesis understands, prior art in shooting process, often accurately exposes journey because cannot obtain
Degree, is that subsequent images process to provide and incorrect feed back or misled, thus when causing subsequently to shoot, acquisition is still
It is so the bad image of quality.
Content of the invention
The embodiment of the present invention provides a kind of method, device and digital imaging system of analysis digital image exposure degree, with
There is provided accurate exposure parameter for imaging device, obtain the preferable image of quality.
A kind of method of analysis digital image exposure degree, methods described includes：
If the form of the digital image obtaining is not gray scale, described digital image is converted into gray scale digital image；
Statistics with histogram is carried out to described gray scale digital image, to obtain the grey level histogram of described gray scale digital image；
According to described grey level histogram, after the pixel intensity analyzing described gray scale digital image, export described digital image
Depth of exposure numerical value.
A kind of device of analysis digital image exposure degree, described device includes：
Format converting module, if the form of the digital image for obtaining not is gray scale, described digital image is changed
Become gray scale digital image；
Histogram extraction module, for carrying out statistics with histogram to described gray scale digital image, to obtain described grey
The grey level histogram of code image；
Analysis module, for according to described grey level histogram, exporting after analyzing the pixel intensity of described gray scale digital image
The depth of exposure numerical value of described digital image.
A kind of digital imaging system, described system includes imaging device, analysis digital image exposure degree device and exposure
Control unit, described analysis digital image exposure degree device includes format converting module, histogram extraction module and analysis mould
Block；
Described imaging device, for obtaining digital image；
Described format converting module, if the form of the digital image for obtaining not is gray scale, by described digital image
It is converted into gray scale digital image；
Described histogram extraction module, for carrying out statistics with histogram to described gray scale digital image, to obtain described ash
The grey level histogram of degree digital image；
Described analysis module, for according to described grey level histogram, after analyzing the pixel intensity of described gray scale digital image
Export the depth of exposure numerical value of described digital image；
Described exposure control unit, for recalculating exposure ginseng according to the depth of exposure numerical value that described analysis module exports
Number, controls described imaging device obtaining the exposure carrying out during digital image.
Knowable to the embodiments of the present invention, due to statistics with histogram acquisition can be carried out according to gray scale digital image
The grey level histogram of gray scale digital image, exports the exposure of described digital image after the pixel intensity analyzing this gray scale digital image
Degree numerical value, these processes all need not manually visually can be participated in by software processing, therefore, compared with prior art, the present invention
Embodiment provides a kind of quick, easy depth of exposure analysis method, applies in the imaging system similar to digital camera
When, the depth of exposure of preview image can be identified before imaging, provide depth of exposure to imaging system, thus helping imaging system
Adjustment exposure parameter, after imaging, can quickly judge the depth of exposure of digital image, for ill-exposed digital image
Directly give prompting, facilitate user's adjustment exposure parameter to shoot again.When the method is applied in Image Management and processes in software
When, can whether ill-exposed with the depth of exposure of automatic decision digital image, to help user to select image, in the exposure in later stage
Compensation program adjusts compensating parameter.
Brief description
Fig. 1 is the basic procedure schematic diagram of the method for analysis digital image exposure degree provided in an embodiment of the present invention；
Fig. 2 is the device logical construction schematic diagram of analysis digital image exposure degree provided in an embodiment of the present invention；
Fig. 3 is the device logical construction schematic diagram of the analysis digital image exposure degree that another embodiment of the present invention provides；
Fig. 4 is the device logical construction schematic diagram of the analysis digital image exposure degree that another embodiment of the present invention provides；
Fig. 5 is digital imaging system logical construction schematic diagram provided in an embodiment of the present invention；
Fig. 6 is the digital imaging system logical construction schematic diagram that another embodiment of the present invention provides；
Fig. 7 is the digital imaging system logical construction schematic diagram that another embodiment of the present invention provides.
Specific embodiment
The embodiment of the present invention provides a kind of method of analysis digital image exposure degree, including：If the digital image obtaining
Form be not gray scale, then described digital image is converted into gray scale digital image；Nogata is carried out to described gray scale digital image
Figure statistics, to obtain the grey level histogram of described gray scale digital image；According to described grey level histogram, analyze described gray scale digital
The depth of exposure numerical value of described digital image is exported after the pixel intensity of image.The embodiment of the present invention also provides corresponding analysis number
The device of code image exposure degree and a kind of digital imaging system.It is described in detail individually below.
The basic procedure of the method for analysis digital image exposure degree of the embodiment of the present invention refers to Fig. 1, main inclusion
Step：
S101, if the form of the digital image obtaining is not gray scale, described digital image is converted into gray scale number shadow
Picture.
Due to the image of various factors, imaging device, such as digital camera, the smart mobile phone with camera or other
The digital image that image modalities are obtained, its form is all not gray scale（Gray）Form.For example, some digital images are
Rgb format, some digital images are yuv formats, and digital image also is YCrCb form, etc..In the embodiment of the present invention
In, if the form of the digital image of imaging device acquisition is not gray scale, these digital images is entered with row format conversion, is allowed to into
For gray scale digital image.
S102, carries out statistics with histogram to described gray scale digital image, straight with the gray scale that obtains described gray scale digital image
Fang Tu.
For gray scale digital image, between its grey level generally 0 to 255 in any one number.Real in the present invention
Apply in example, the grey level histogram of gray scale digital image is the set of f (i), and the grey level histogram of even gray scale digital image uses f
Represent, then f={ f (0), f (1) ..., f (i) ..., f (255) }, the value of f (i) is grey level in gray scale digital image here
The number of the pixel for i, and i ∈ [0,255].Obviously, when in gray scale digital image, pixel total number is N,
S103, according to described grey level histogram, exports described number after the pixel intensity analyzing described gray scale digital image
The depth of exposure numerical value of image.
As one embodiment of the invention, according to grey level histogram, export after analyzing the pixel intensity of gray scale digital image
The depth of exposure numerical value of digital image includes step S31 and step S32：
S31, the low dark pixel number according to grey level histogram reflection and high luminance pixels number, obtain the exposure of digital image
Degree E.
In embodiments of the present invention, the scope of several grey levels can be pre-set, for example, setting grey level [0,
T1] and grey level [T2, 255], T2With T1There may be following relation T1=255—T2, T1Value be ordinarily selected to 60 about,
For example, T1Take 60, then T2Desirable 195.After pre-setting grey level, grey level in gray scale digital image can be counted
[0, T1] number of pixels N1With grey level in [T2, 255] number of pixels N2, then：
In embodiments of the present invention, can be by grey level in gray scale digital image [0, T1] pixel as low dark picture
Element, by grey level in [T2, 255] pixel as high luminance pixels, calculate (N2-N1)/(N1+N2), if N1+N2=0, then expose
Degree E is considered as 0, otherwise, with (N2-N1)/(N1+N2) as exposure E, that is,：
S32, by the relation of described exposure E and predefined exposure threshold value and/or shading value proportion threshold value, exports institute
State exposure E and depth of exposure rank.
In embodiments of the present invention, predefined exposure threshold value includes the first exposure threshold value th1, the second exposure threshold
Value th11, the 3rd exposure threshold value th2With the 4th exposure threshold value th22, predefined shading value proportion threshold value includes the first light and shade
Degree proportion threshold value te1, the second shading value proportion threshold value te11, the 3rd shading value proportion threshold value te2With the 4th shading value proportion threshold value
te22, wherein, th1More than 0, th11More than th1, th2Less than 0, th22More than th2, te11More than te1, te22More than te2；Exposure journey
Degree rank includes that exposure is normal, overexposure, serious overexposure, under-exposure and seriously under-exposure.
As one embodiment of the invention, by exposure E and predefined exposure threshold value and/or shading value proportion threshold value
Relation, output exposure E and depth of exposure rank include：
If by formula（1）Calculated exposure E is 0, then output " exposes normally " this depth of exposure rank and by formula
（1）Calculated exposure E；
If by formula（1）Calculated exposure E is more than the first exposure threshold value th1, and E1More than the first shading value ratio
Threshold value te1, then export " overexposure " this depth of exposure rank and by formula（1）Calculated exposure E, herein, E1Definition
For E1=N1/ N, N1With the meaning of N as it was previously stated, grey level is [0, T respectively in gray scale digital image1] number of pixels and
Pixel total number in gray scale digital image；
If by formula（1）Calculated exposure E is more than the second exposure threshold value th11, and E1More than the second shading value ratio
Example threshold value te11, then export " serious overexposure " this depth of exposure rank and by formula（1）Calculated exposure E；
If by formula（1）Calculated exposure E is less than the 3rd exposure threshold value th2, and E1More than the 3rd shading value ratio
Threshold value te2, then export " under-exposure " this depth of exposure rank and by formula（1）Calculated exposure E；
If by formula（1）Calculated exposure E is less than the 4th exposure threshold value th22, and E1Less than the 4th shading value ratio
Example threshold value te22, then export " seriously under-exposure " this depth of exposure rank and by formula（1）Calculated exposure E.
Knowable to the method for the analysis digital image exposure degree that the embodiments of the present invention provide, due to can be according to right
Gray scale digital image carries out the grey level histogram of the gray scale digital image of statistics with histogram acquisition, analyzes this gray scale digital image
The depth of exposure numerical value of described digital image is exported, these processes all can be by software processing, need not artificial meat after pixel intensity
Eye participates in, and therefore, compared with prior art, embodiments provides a kind of quick, easy depth of exposure analysis method,
The depth of exposure of preview image when applying in the imaging system similar to digital camera, can be identified before imaging, to imaging
System provides depth of exposure, thus helping imaging system adjustment exposure parameter, after imaging, can quickly judge digital image
Depth of exposure, prompting is directly given for ill-exposed digital image, facilitate user adjustment exposure parameter shoot again.When
When the method is applied in Image Management and processed in software, whether can be exposed not with the depth of exposure of automatic decision digital image
Good, to help user to select image, the exposure compensating program in the later stage adjusts compensating parameter.
Analysis to the embodiment of the present invention of the method for executing above-mentioned analysis digital image exposure degree is digital below
The device of image exposure degree illustrates, and its basic logical structure, with reference to Fig. 2, mainly includes format converting module 201, Nogata
Figure extraction module 202 and analysis module 203, each module describes in detail as follows：
Format converting module 201, if the form of the digital image for obtaining not is gray scale, described digital image is turned
Change gray scale digital image into；
Histogram extraction module 202, for carrying out statistics with histogram to described gray scale digital image, to obtain described gray scale
The grey level histogram of digital image；
Analysis module 203, defeated after the pixel intensity of described gray scale digital image for according to described grey level histogram, analyzing
Go out the depth of exposure numerical value of described digital image.
It should be noted that in the embodiment of device of analysis digital image exposure degree of the figures above 2 example, respectively
The division of functional module is merely illustrative of, in practical application can as needed, the configuration requirement of for example corresponding hardware or
The convenient consideration of the realization of software, and above-mentioned functions distribution is completed by different functional modules, will described analysis number shadow
As the internal structure of the device of depth of exposure is divided into different functional modules, to complete all or part of work(described above
Energy.And, in practical application, the corresponding functional module in the present embodiment can be realized by corresponding hardware it is also possible to by
Corresponding hardware executes corresponding software and completes, and for example, aforesaid format converting module, if can be to have the aforementioned acquisition of execution
The form of digital image when being not gray scale, described digital image is converted into the hardware of gray scale digital image, such as form turns
Parallel operation or be able to carry out corresponding computer program thus completing the general processor of aforementioned function or other hardware set
Standby；For another example aforesaid analysis module, can be have execution aforementioned according to described grey level histogram, analyze described gray scale number shadow
The hardware of the depth of exposure numerical value function of described digital image, such as analyzer or energy is exported after the pixel intensity of picture
Enough execution corresponding computer programs are thus complete general processor or other hardware devices of aforementioned function（This specification provides
Each embodiment all can apply foregoing description principle）.
In the device of analysis digital image exposure degree of accompanying drawing 2 example, grey level histogram is the set of f (i), f's (i)
It is worth the number of the pixel being i for grey level in described gray scale digital image, wherein, i ∈ [0,255], analysis module 203 is permissible
Including exposure acquiring unit 301 and parameter output unit 302, the analysis that another embodiment of the present invention provides as shown in Figure 3
The device of digital image exposure degree, wherein：
Exposure acquiring unit 301, for the low dark pixel number that reflected according to described grey level histogram and high luminance pixels
Number, obtains exposure E of described digital image.
Parameter output unit 302, for by described exposure E and predefined exposure threshold value and/or shading value ratio
The relation of threshold value, exports described exposure E and depth of exposure rank.
In the device of analysis digital image exposure degree of accompanying drawing 3 example, exposure threshold value includes the first exposure threshold value
th1, the second exposure threshold value th11, the 3rd exposure threshold value th2With the 4th exposure threshold value th22, described shading value proportion threshold value
Including the first shading value proportion threshold value te1, the second shading value proportion threshold value te11, the 3rd shading value proportion threshold value te2Bright with the 4th
Darkness proportion threshold value te22, described th1More than 0, described th11More than described th1, described th2Less than 0, described th22More than described
th2, described te11More than described te1, described te22More than described te2；Depth of exposure rank includes that exposure is normal, overexposure,
Serious overexposure, under-exposure and seriously under-exposure.Exposure acquiring unit 301 can include statistic unit 406 and calculate single
Unit 407, parameter output unit 302 can include the first output unit 401, the second output unit 402, the 3rd output unit 403,
4th output unit 404 and the 5th output unit 405, the analysis number shadow that another embodiment of the present invention provides as shown in Figure 4
The device of picture depth of exposure, wherein：
Statistic unit 406, for counting in described gray scale digital image grey level [0, T1] number of pixels N1And ash
Degree rank is in [T2, 255] number of pixels N2, in described gray scale digital image, grey level is [0, T1] pixel be described low
Dark pixel, described grey level is in [T2, 255] pixel be high luminance pixels；
Computing unit 407, if for N1+N2=0, then described exposure E is 0, otherwise, calculates (N2-N1)/(N1+N2), with
Described (N2-N1)/(N1+N2) it is described exposure E.
In the device of the analysis digital image exposure degree of accompanying drawing 3 or accompanying drawing 4 example, several gray scales can be pre-set
Rank, for example, arranges grey level [0, T1] and grey level [T2, 255], T2With T1There may be following relation T1=255—T2,
T1Value be ordinarily selected to 60 about, for example, T1Take 60, then T2Desirable 195.After pre-setting grey level, statistics is single
Unit 406 can count in gray scale digital image grey level [0, T1] number of pixels N1With grey level in [T2, 255]
Number of pixels N2, then：
In the device of the analysis digital image exposure degree of accompanying drawing 3 or accompanying drawing 4 example, can be by gray scale digital image
Grey level is [0, T1] pixel as low dark pixel, by grey level in [T2, 255] pixel as high luminance pixels, calculate
Unit 407 calculates (N2-N1)/(N1+N2), if N1+N2=0, then exposure E be considered as 0, otherwise, with (N2-N1)/(N1+N2) as exposure
Luminosity E, that is,：
First output unit 401, if for by formula（1）Calculated exposure E is 0, then output " exposes normally " this
One depth of exposure rank and by formula（1）Calculated exposure E；
Second output unit 402, if for by formula（1）Calculated exposure E is more than the first exposure threshold value th1,
And E1More than the first shading value proportion threshold value te1, then export " overexposure " this depth of exposure rank and by formula（1）Calculate
Exposure E arriving, herein, E1It is defined as E1=N1/ N, N1With the meaning of N as it was previously stated, gray scale respectively in gray scale digital image
Rank is [0, T1] number of pixels and gray scale digital image in pixel total number；
3rd output unit 403, if for by formula（1）Calculated exposure E is more than the second exposure threshold value th11,
And E1More than the second shading value proportion threshold value te11, then export " serious overexposure " this depth of exposure rank and by formula（1）Meter
Exposure E obtaining；
4th output unit 404, if for by formula（1）Calculated exposure E is less than the 3rd exposure threshold value th2,
And E1More than the 3rd shading value proportion threshold value te2, then export " under-exposure " this depth of exposure rank and by formula（1）It is calculated
Exposure E；
5th output unit 405, if for by formula（1）Calculated exposure E is less than the 4th exposure threshold value th22,
And E1Less than the 4th shading value proportion threshold value te22, then export " seriously under-exposure " this depth of exposure rank and by formula（1）Calculate
Exposure E obtaining.
Refer to accompanying drawing 5, be a kind of digital imaging system provided in an embodiment of the present invention, it includes imaging device 501, divides
Analysis digital image exposure degree device 502 and exposure control unit 503, wherein, analysis digital image exposure degree device 502 wraps
Include format converting module 5021, histogram extraction module 5022 and analysis module 5023, each device module unit describe in detail
As follows：
Imaging device 501, for obtaining digital image；
Format converting module 5021, if the form of the digital image obtaining for imaging device 501 is not gray scale, by institute
State digital image and be converted into gray scale digital image；
Histogram extraction module 5022, for carrying out statistics with histogram to described gray scale digital image, to obtain described ash
The grey level histogram of degree digital image；
Analysis module 5023, for according to described grey level histogram, after analyzing the pixel intensity of described gray scale digital image
Export the depth of exposure numerical value of described digital image；
Exposure control unit 503, for recalculating exposure ginseng according to the depth of exposure numerical value that analysis module 5023 exports
Number, controls described imaging device obtaining the exposure carrying out during digital image.
In the digital imaging system of accompanying drawing 5 example, grey level histogram is the set of f (i), and the value of f (i) is gray scale number shadow
In picture, grey level is the number of the pixel of i, wherein, i ∈ [0,255], analysis module 5023 can include exposure and obtain list
Unit 601 and parameter output unit 602, the digital imaging system that another embodiment of the present invention provides as shown in Figure 6, wherein：
Exposure acquiring unit 601, for the low dark pixel number that reflected according to described grey level histogram and high luminance pixels
Number, obtains exposure E of described digital image.
Parameter output unit 602, for by described exposure E and predefined exposure threshold value and/or shading value ratio
The relation of threshold value, exports described exposure E and depth of exposure rank.
In the digital imaging system of accompanying drawing 6 example, exposure threshold value includes the first exposure threshold value th1, the second exposure
Threshold value th11, the 3rd exposure threshold value th2With the 4th exposure threshold value th22, described shading value proportion threshold value includes the first shading value
Proportion threshold value te1, the second shading value proportion threshold value te11, the 3rd shading value proportion threshold value te2With the 4th shading value proportion threshold value
te22, described th1More than 0, described th11More than described th1, described th2Less than 0, described th22More than described th2, described te11Greatly
In described te1, described te22More than described te2；Depth of exposure rank includes that exposure is normal, overexposure, serious overexposure,
Under-exposure and seriously under-exposure.Exposure acquiring unit 601 can include statistic unit 706 and computing unit 707, and parameter exports
Unit 602 can include the first output unit 701, the second output unit 702, the 3rd output unit 703, the 4th output unit
704 and the 5th output unit 705, the digital imaging system that another embodiment of the present invention provides as shown in Figure 7, wherein：
Statistic unit 706, for counting in described gray scale digital image grey level [0, T1] number of pixels N1And ash
Degree rank is in [T2, 255] number of pixels N2, in described gray scale digital image, grey level is [0, T1] pixel be described low
Dark pixel, described grey level is in [T2, 255] pixel be high luminance pixels；
Computing unit 707, if for N1+N2=0, then described exposure E is 0, otherwise, calculates (N2-N1)/(N1+N2), with
Described (N2-N1)/(N1+N2) it is described exposure E.
In the digital imaging system of accompanying drawing 6 or accompanying drawing 7 example, several grey levels can be pre-set, for example, setting
Grey level [0, T1] and grey level [T2, 255], T2With T1There may be following relation T1=255—T2, T1Value generally select
It is selected as 60 about, for example, T1Take 60, then T2Desirable 195.After pre-setting grey level, statistic unit 706 can count
In gray scale digital image, grey level is [0, T1] number of pixels N1With grey level in [T2, 255] number of pixels N2, then：
In the digital imaging system of accompanying drawing 6 or accompanying drawing 7 example, can by grey level in gray scale digital image [0,
T1] pixel as low dark pixel, by grey level in [T2, 255] pixel as high luminance pixels, computing unit 707 calculates
(N2-N1)/(N1+N2), if N1+N2=0, then exposure E be considered as 0, otherwise, with (N2-N1)/(N1+N2) as exposure E, that is,：
First output unit 701, if for by formula（1）Calculated exposure E is 0, then output " exposes normally " this
One depth of exposure rank and by formula（1）Calculated exposure E；
Second output unit 702, if for by formula（1）Calculated exposure E is more than the first exposure threshold value th1,
And E1More than the first shading value proportion threshold value te1, then export " overexposure " this depth of exposure rank and by formula（1）Calculate
Exposure E arriving, herein, E1It is defined as E1=N1/ N, N1With the meaning of N as it was previously stated, gray scale respectively in gray scale digital image
Rank is [0, T1] number of pixels and gray scale digital image in pixel total number；
3rd output unit 703, if for by formula（1）Calculated exposure E is more than the second exposure threshold value th11,
And E1More than the second shading value proportion threshold value te11, then export " serious overexposure " this depth of exposure rank and by formula（1）Meter
Exposure E obtaining；
4th output unit 704, if for by formula（1）Calculated exposure E is less than the 3rd exposure threshold value th2,
And E1More than the 3rd shading value proportion threshold value te2, then export " under-exposure " this depth of exposure rank and by formula（1）It is calculated
Exposure E；
5th output unit 705, if for by formula（1）Calculated exposure E is less than the 4th exposure threshold value th22,
And E1Less than the 4th shading value proportion threshold value te22, then export " seriously under-exposure " this depth of exposure rank and by formula（1）Calculate
Exposure E obtaining.
It should be noted that the content such as information exchange between each module/unit of said apparatus, implementation procedure, due to
The inventive method embodiment is based on same design, and the technique effect that it brings is identical with the inventive method embodiment, particular content
Can be found in the narration in the inventive method embodiment, here is omitted.
One of ordinary skill in the art will appreciate that all or part of step in the various methods of above-described embodiment is can
Completed with the hardware instructing correlation by program, this program can be stored in a computer-readable recording medium, storage
Medium can include：Read-only storage（ROM, Read Only Memory）, random access memory（RAM, Random
Access Memory）, disk or CD etc..
The method of analysis digital image exposure the degree above embodiment of the present invention being provided, device become with a kind of numeral
As system is described in detail, specific case used herein is set forth to the principle of the present invention and embodiment,
The explanation of above example is only intended to help and understands the method for the present invention and its core concept；Simultaneously for this area one
As technical staff, according to the present invention thought, all will change in specific embodiments and applications, to sum up institute
State, this specification content should not be construed as limitation of the present invention.
Claims (3)
1. a kind of method of analysis digital image exposure degree is it is characterised in that methods described includes：
If the form of the digital image obtaining is not gray scale, described digital image is converted into gray scale digital image；
Statistics with histogram is carried out to described gray scale digital image, to obtain the grey level histogram of described gray scale digital image；
According to described grey level histogram, after the pixel intensity analyzing described gray scale digital image, export the exposure of described digital image
Degree numerical value；
Described grey level histogram is the set of f (i), and the value of described f (i) is that in described gray scale digital image, grey level is i
The number of pixel, described i ∈ [0,255]；
Described according to described grey level histogram, export described digital image after the pixel intensity analyzing described gray scale digital image
Depth of exposure numerical value includes：
Low dark pixel number according to the reflection of described grey level histogram and high luminance pixels number, obtain the exposure of described digital image
Degree E；
By the relation of described exposure E and predefined exposure threshold value and/or shading value proportion threshold value, export described exposure
E and depth of exposure rank；Described exposure threshold value includes the first exposure threshold value th1, the second exposure threshold value th11, the 3rd exposure
Luminosity threshold value th2With the 4th exposure threshold value th22, described shading value proportion threshold value includes the first shading value proportion threshold value te1,
Two shading value proportion threshold value te11, the 3rd shading value proportion threshold value te2With the 4th shading value proportion threshold value te22, described th1It is more than
0, described th11More than described th1, described th2Less than 0, described th22More than described th2, described te11More than described te1, described
te22More than described te2；
The described low dark pixel number according to the reflection of described grey level histogram and high luminance pixels number, obtain described digital image
Exposure E includes：Count in described gray scale digital image grey level [0, T1] number of pixels N1With grey level in [T2,
255] number of pixels N2, in described gray scale digital image, grey level is [0, T1] pixel be described low dark pixel, described ash
Degree rank is in [T2, 255] pixel be high luminance pixels；If N1+N2=0, then described exposure E is 0, otherwise, calculates (N2-N1)/
(N1+N2), with described (N2-N1)/(N1+N2) it is described exposure E；
The described relation by described exposure E and predefined exposure threshold value and/or shading value proportion threshold value, exports described exposure
Luminosity E and depth of exposure rank include：
If described exposure E is 0, output exposes normal and described exposure E；
If described exposure E is more than described th1, and E1More than described te1, then output overexposure and described exposure E, described E1
=N1/ N, described N are pixel total number in described gray scale digital image；
If described exposure E is more than described th11, and described E1More than described te11, then serious overexposure and described exposure are exported
Degree E；
If described exposure E is less than described th2, and described E1Less than described te2, then export under-exposure and described exposure E；
If described exposure E is less than described th22, and described E1Less than described te22, then export seriously under-exposure and described exposure
E.
2. a kind of device of analysis digital image exposure degree is it is characterised in that described device includes：
Format converting module, if the form of the digital image for obtaining not is gray scale, described digital image is converted into ash
Degree digital image；
Histogram extraction module, for carrying out statistics with histogram to described gray scale digital image, to obtain described gray scale number shadow
The grey level histogram of picture；
Analysis module, for according to described grey level histogram, after analyzing the pixel intensity of described gray scale digital image, output is described
The depth of exposure numerical value of digital image；
Described grey level histogram is the set of f (i), and the value of described f (i) is that in described gray scale digital image, grey level is i
The number of pixel, described i ∈ [0,255], described analysis module includes：
Exposure acquiring unit, for the low dark pixel number that reflected according to described grey level histogram and high luminance pixels number, obtains
Obtain exposure E of described digital image；
Parameter output unit, for the pass by described exposure E and predefined exposure threshold value and/or shading value proportion threshold value
System, exports described exposure E and depth of exposure rank；
Described exposure threshold value includes the first exposure threshold value th1, the second exposure threshold value th11, the 3rd exposure threshold value th2With
4th exposure threshold value th22, described shading value proportion threshold value includes the first shading value proportion threshold value te1, the second shading value ratio
Threshold value te11, the 3rd shading value proportion threshold value te2With the 4th shading value proportion threshold value te22, described th1More than 0, described th11It is more than
Described th1, described th2Less than 0, described th22More than described th2, described te11More than described te1, described te22More than described te2；
Described exposure acquiring unit includes statistic unit and computing unit；
Described statistic unit, for counting in described gray scale digital image grey level [0, T1] number of pixels N1And gray scale
Rank is in [T2, 255] number of pixels N2, in described gray scale digital image, grey level is [0, T1] pixel be described low dark
Pixel, described grey level is in [T2, 255] pixel be high luminance pixels；
Described computing unit, if for N1+N2=0, then described exposure E is 0, otherwise, calculates (N2-N1)/(N1+N2), with institute
State (N2-N1)/(N1+N2) it is described exposure E；
Described parameter output unit include the first output unit, the second output unit, the 3rd output unit, the 4th output unit and
5th output unit；
Described first output unit, if being 0 for described exposure E, output exposes normal and described exposure E；
Described second output unit, if be more than described th for described exposure E1, and E1More than described te1, then export and excessively expose
Light and described exposure E, described E1=N1/ N, described N are pixel total number in described gray scale digital image；
Described 3rd output unit, if be more than described th for described exposure E11, and described E1More than described te11, then export
Serious overexposure and described exposure E；
Described 4th output unit, if be less than described th for described exposure E2, and described E1Less than described te2, then export and owe
Exposure and described exposure E；
Described 5th output unit, if be less than described th for described exposure E22, and described E1Less than described te22, then export
Seriously under-exposure and described exposure E.
3. a kind of digital imaging system is it is characterised in that described system includes imaging device, analysis digital image exposure degree dress
Put and exposure control unit, described analysis digital image exposure degree device includes format converting module, histogram extraction module
And analysis module；
Described imaging device, for obtaining digital image；
Described format converting module, if the form of the digital image for obtaining not is gray scale, described digital image is changed
Become gray scale digital image；
Described histogram extraction module, for carrying out statistics with histogram to described gray scale digital image, to obtain described grey
The grey level histogram of code image；
Described analysis module, for according to described grey level histogram, exporting after analyzing the pixel intensity of described gray scale digital image
The depth of exposure numerical value of described digital image；
Described exposure control unit, for exposure parameter is recalculated according to the depth of exposure numerical value that described analysis module exports,
Described imaging device is controlled to obtain the exposure carrying out during digital image；
Described grey level histogram is the set of f (i), and the value of described f (i) is that in described gray scale digital image, grey level is i
The number of pixel, described i ∈ [0,255], described analysis module includes：
Exposure acquiring unit, for the low dark pixel number that reflected according to described grey level histogram and high luminance pixels number, obtains
Obtain exposure E of described digital image；
Parameter output unit, for the pass by described exposure E and predefined exposure threshold value and/or shading value proportion threshold value
System, exports described exposure E and depth of exposure rank；
Described exposure threshold value includes the first exposure threshold value th1, the second exposure threshold value th11, the 3rd exposure threshold value th2With
4th exposure threshold value th22, described shading value proportion threshold value includes the first shading value proportion threshold value te1, the second shading value ratio
Threshold value te11, the 3rd shading value proportion threshold value te2With the 4th shading value proportion threshold value te22, described th1More than 0, described th11It is more than
Described th1, described th2Less than 0, described th22More than described th2, described te11More than described te1, described te22More than described te2；
Described exposure acquiring unit includes statistic unit and computing unit；
Described statistic unit, for counting in described gray scale digital image grey level [0, T1] number of pixels N1And gray scale
Rank is in [T2, 255] number of pixels N2, in described gray scale digital image, grey level is [0, T1] pixel be described low dark
Pixel, described grey level is in [T2, 255] pixel be high luminance pixels；
Described computing unit, if for N1+N2=0, then described exposure E is 0, otherwise, calculates (N2-N1)/(N1+N2), with institute
State (N2-N1)/(N1+N2) it is described exposure E；
Described parameter output unit include the first output unit, the second output unit, the 3rd output unit, the 4th output unit and
5th output unit；
Described first output unit, if being 0 for described exposure E, output exposes normal and described exposure E；
Described second output unit, if be more than described th for described exposure E1, and E1More than described te1, then export and excessively expose
Light and described exposure E, described E1=N1/ N, described N are pixel total number in described gray scale digital image；
Described 3rd output unit, if be more than described th for described exposure E11, and described E1More than described te11, then export
Serious overexposure and described exposure E；
Described 4th output unit, if be less than described th for described exposure E2, and described E1Less than described te2, then export and owe
Exposure and described exposure E；
Described 5th output unit, if be less than described th for described exposure E22, and described E1Less than described te22, then export
Seriously under-exposure and described exposure E.
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| CN106375602B (en) * | 2016-10-31 | 2019-09-20 | 努比亚技术有限公司 | Terminal photographic method and device |
| CN109922274B (en) * | 2017-12-13 | 2021-05-14 | 深圳英飞拓科技股份有限公司 | Camera highlight suppression method and device based on histogram |
| CN111970462A (en) * | 2020-08-20 | 2020-11-20 | Oppo（重庆）智能科技有限公司 | Exposure processing method, exposure processing apparatus, electronic device, and computer-readable storage medium |
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