CN107454340A - Image combining method, device and mobile terminal based on HDR principle - Google Patents
Image combining method, device and mobile terminal based on HDR principle Download PDFInfo
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- CN107454340A CN107454340A CN201710630424.XA CN201710630424A CN107454340A CN 107454340 A CN107454340 A CN 107454340A CN 201710630424 A CN201710630424 A CN 201710630424A CN 107454340 A CN107454340 A CN 107454340A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/70—Circuitry for compensating brightness variation in the scene
- H04N23/741—Circuitry for compensating brightness variation in the scene by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/222—Studio circuitry; Studio devices; Studio equipment
- H04N5/262—Studio circuits, e.g. for mixing, switching-over, change of character of image, other special effects ; Cameras specially adapted for the electronic generation of special effects
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Abstract
The invention discloses a kind of image combining method based on HDR principle, device and mobile terminal, methods described includes：Gather the image of multiple different exposure parameters；The image of multiple different exposure parameters is synthesized based on HDR principle, obtains high dynamic range images；Tone mapping is carried out to high dynamic range images, is re-compressed the pixel of high dynamic range images；Described device includes image capture module, image synthesis unit and tone mapping block；The mobile terminal includes processor and the memory for storing processor executable program, during the program of computing device memory storage, realizes the operation of the above method.The present invention carries out tone mapping by being synthesized the image of multiple different exposure parameters to obtain high dynamic range images, has both improved image interior details, has remained image edge detailss again.
Description
Technical field
The present invention relates to a kind of image combining method, especially a kind of image synthesis side based on HDR principle
Method, device and mobile terminal, belong to image processing field.
Background technology
With the popularization of certificate, the information such as Hongkong and Macro's pass, the Taiwan pass, passport, identity card is required for believing individual
The verification of breath.The each accreditation of applicant is required for re-shooting the certificate photo for meeting accreditation requirement.
With the popularization that mobile phone is shot, its shoot function is also become stronger day by day, but still suffers from problems with：
1) due to reasons such as shooting environmental difference or subject surface reflections, and the global illumination shot is caused
Inequality, causing photo processing system, system is difficult to extract the information of details when reading information；
2) during character image is read, light problem during shooting can cause the image after shooting to occur largely making an uproar
Point, so as to cause the Color Channel of image to shift, then system occurs when reading face or background area information
Error；
3) be difficult to ensure that light stabilisation, it is necessary to by system to take come photo do a processing by external environment condition and people
Thing image separation, while character details' information is also separated, but this processing mode is cumbersome.
Therefore, using the photo of mobile phone shooting in follow-up image procossing, its detailed information can not fully be separated
Out, the photo come is taken in the case where other people assist and is also difficult to the requirement for meeting accreditation；And in the photographic unit for having perfect configuration
Shot, costly, and shooting effect is bad for charge, when dissatisfied shooting effect is wanted to retake, it is necessary to photography
Shi Chongxin is linked up and discussed, time and effort consuming.
For high dynamic range images (High-DynamicRange, abbreviation HDR) image, the long short exposure two of generally use
Level is realized, but effect is also undesirable, particularly bright with the gloomy scene mixed, bright local and gloomy local mistake
It is bad to cross effect.
The content of the invention
First purpose of the present invention is to solve the defects of above-mentioned prior art, there is provided one kind is based on high dynamic range
The image combining method of principle is enclosed, this method is by being synthesized to obtain HDR the image of multiple different exposure parameters
Image, and tone mapping is carried out, image interior details have both been improved, have remained image edge detailss again.
Second object of the present invention is to provide a kind of image synthesis system based on HDR principle.
Third object of the present invention is to provide a kind of mobile terminal.
First purpose of the present invention can be reached by adopting the following technical scheme that：
A kind of image combining method based on HDR principle, methods described include：
Gather the image of multiple different exposure parameters；
The image of multiple different exposure parameters is synthesized based on HDR principle, obtains HDR figure
Picture；
Tone mapping is carried out to high dynamic range images, is re-compressed the pixel of high dynamic range images.
Further, it is described to be synthesized the image of multiple different exposure parameters based on HDR principle, obtain
High dynamic range images, specifically include：
The Pixel-level of the image of multiple different exposure parameters is extended；
The average value of the pixel value after the image spreading of multiple different exposure parameters is taken, obtains high dynamic range images.
Further, the Pixel-level by the image of multiple different exposure parameters is extended, and is specially：
Each pixel in the image of multiple different exposure parameters is multiplied by 28~264, reaching each pixel can accommodate
216~272The pixel of individual level.
Further, tone mapping is carried out to high dynamic range images, the pixel of high dynamic range images is carried out again
Compression, is specifically included：
Multiple 3*3 pixel grid is built in whole high dynamic range images；
For each 3*3 pixel grid, by the pixel of center pixel grid respectively with being centered around eight pixels of surrounding
The pixel of grid is compared；
According to comparative result, when pixel is different from the pixel of center pixel grid in eight pixel grids for be centered around surrounding
Pixel grid quantity more than two when, center pixel grid is judged as marginal information；Otherwise, center pixel grid is judged
For general information；
Mapping processing is carried out to the pixel of all center pixel grids for being judged as general information, makes high dynamic range images
Pixel re-compressed.
Further, it is centered around the pixel that pixel is different from the pixel of center pixel grid in eight pixel grids of surrounding
Grid refers to：
It is centered around the pixel grid that pixel in eight pixel grids of surrounding is more than the pixel of m times of center pixel grid；Its
In, 1<m<1.2；
Or it is centered around the pixel grid that pixel in eight pixel grids of surrounding is less than the pixel of n times of center pixel grid；
Wherein, 0.8<n<1.
Further, the pixel of described pair of all center pixel grids for being judged as general information carries out mapping processing, makes
The pixel of high dynamic range images is re-compressed, and is specifically included：
The mapping value of the pixel of all center pixel grids for being judged as general information is calculated, it is as follows：
F (x, y)=ln (p (x, y))/ln (cl)-ln (p)/ln (cl)
Wherein, p (x, y) is the pixel of eight pixel grids of 3*3 pixel grid surroundings, and p is 3*3 pixel sides center of a lattice
The pixel of pixel grid, cl are reduced parameter, and f (x, y) is the pixel-map value of 3*3 pixel grids；
The weights of all center pixel grids for being judged as general information are calculated, it is as follows：
Wherein, w (x, y) is the pixel weights of 3*3 pixel grids；
Mapping value f (x, y) after calculating and weight w (x, y) are substituted into following formula：
F'(x, y)=f (x, y) * w (x, y)
The f'(x that will be calculated, y) substitute into following formula：
Wm=∑s f'(x, y)/∑ w (x, y)
Wherein, wm is a numerical value in computing；
The wm being calculated is substituted into following formula：
L (x, y)=e(wm+(p(x,y)/log(cl)))*log(cl)
Wherein, l (x, y) is pixel value；
Pixel value l (x, y) is normalized in 0~255 level.
Second object of the present invention can be reached by adopting the following technical scheme that：
A kind of image synthesizer based on HDR principle, described device include：
Image capture module, for gathering the image of multiple different exposure parameters；
Image synthesis unit, for the image of multiple different exposure parameters to be synthesized based on HDR principle,
Obtain high dynamic range images；
Tone mapping block, for carrying out tone mapping to high dynamic range images, make the pixel of high dynamic range images
Re-compressed.
Further, described image synthesis module, specifically include：
Pixel-level expanding element, for the Pixel-level of the image of multiple different exposure parameters to be extended；
Averaging unit, the average value of the pixel value after image spreading for taking multiple different exposure parameters, obtain high dynamic
State range image.
Further, the Pixel-level expanding element, it is specially：
Each pixel in the image of multiple different exposure parameters is multiplied by 28~264, reaching each pixel can accommodate
216~272The pixel of individual level.
Further, the tone mapping block, is specifically included：
Pixel grid construction unit, for building multiple 3*3 pixel grid in whole high dynamic range images；
Comparing unit, for the pixel grid for each 3*3, by the pixel of center pixel grid respectively with being centered around four
The pixel of eight pixel grids in week is compared；
Judging unit, for according to comparative result, when pixel and center pixel in eight pixel grids for be centered around surrounding
During the different pixel grid quantity more than two of the pixel of grid, center pixel grid is judged as marginal information；Otherwise, by
Imago element grid is judged as general information；
Map unit, for carrying out mapping processing to the pixel of all center pixel grids for being judged as general information, make
The pixel of high dynamic range images is re-compressed.
Further, it is centered around the pixel that pixel is different from the pixel of center pixel grid in eight pixel grids of surrounding
Grid refers to：
It is centered around the pixel grid that pixel in eight pixel grids of surrounding is more than the pixel of m times of center pixel grid；Its
In, 1<m<1.2；
Or it is centered around the pixel grid that pixel in eight pixel grids of surrounding is less than the pixel of n times of center pixel grid；
Wherein, 0.8<n<1.
Further, in the map unit, tone is carried out to all center pixel grids for being judged as general information and reflected
Processing is penetrated, the pixel of high dynamic range images is re-compressed, specifically included：
The mapping value of the pixel of all center pixel grids for being judged as general information is calculated, it is as follows：
F (x, y)=ln (p (x, y))/ln (cl)-ln (p)/ln (cl)
Wherein, p (x, y) is the pixel of eight pixel grids of 3*3 pixel grid surroundings, and p is 3*3 pixel sides center of a lattice
The pixel of pixel grid, cl are reduced parameter, and f (x, y) is the pixel-map value of 3*3 pixel grids；
The weights of all center pixel grids for being judged as general information are calculated, it is as follows：
Wherein, w (x, y) is the pixel weights of 3*3 pixel grids；
Mapping value f (x, y) after calculating and weight w (x, y) are substituted into following formula：
F'(x, y)=f (x, y) * w (x, y)
The f'(x that will be calculated, y) substitute into following formula：
Wm=∑s f'(x, y)/∑ w (x, y)
Wherein, wm is a numerical value in computing；
The wm being calculated is substituted into following formula：
L (x, y)=e(wm+(p(x,y)/log(cl)))*log(cl)
Wherein, l (x, y) is pixel value；
Pixel value l (x, y) is normalized in 0~255 level.
Third object of the present invention can be reached by adopting the following technical scheme that：
A kind of mobile terminal, including processor and the memory for storing processor executable program, the processing
When device performs the program of memory storage, following operation is realized：
Gather the image of multiple different exposure parameters；
The image of multiple different exposure parameters is synthesized based on HDR principle, obtains HDR figure
Picture；
Tone mapping is carried out to high dynamic range images, is re-compressed the pixel of high dynamic range images.
The present invention has following beneficial effect relative to prior art：
1st, the image of the invention by gathering multiple different exposure parameters, multiple differences are exposed based on HDR principle
The image of optical parameter is synthesized, when the image of synthesis reduces shooting image because of the lighting issues of environment and caused by noise,
Solve the skew in image processing process on Color Channel simultaneously, then the high dynamic range images progress tone of acquisition is reflected
Penetrate, re-compressed the pixel of high dynamic range images, to return to the level that can be shown on mobile terminals again,
And retain details to the full extent.
2nd, the present invention is in the building-up process based on HDR principle, by the picture of the image of multiple different exposure parameters
Plain level is extended, and 2 can be accommodated by reaching each pixel16~272The pixel of individual level, i.e. pixel level reach 216~272Individual layer
Level, can preferably retain image detail, and image is preferably reduced current shooting light.
3rd, the present invention builds multiple 3*3 picture after high dynamic range images are obtained in whole high dynamic range images
Plain grid, analysis judgement is carried out to the center pixel grid of each 3*3 pixel grid, if center pixel grid is believed for edge
Breath, then do not deal with, if center pixel grid is general information, mapping processing carried out to the pixel of center pixel grid,
And the criterion that weights map as tone is added, this sampled images can retain edge details.
Brief description of the drawings
Fig. 1 is the image combining method flow chart of the embodiment of the present invention 1.
Fig. 2 a are the normal exposure parametric image schematic diagram of the embodiment of the present invention 1.
Fig. 2 b are the deficient exposure image schematic diagram of the embodiment of the present invention 1.
Fig. 2 c are the overexposure image schematic diagram of the embodiment of the present invention 1.
Fig. 3 is the acquisition high dynamic range images flow chart of the embodiment of the present invention 1.
Fig. 4 is that the tone of the embodiment of the present invention 1 maps flow chart.
Fig. 5 is the pixel grid schematic diagram that the embodiment of the present invention 1 builds multiple 3*3 in whole high dynamic range images.
Fig. 6 is the final effect figure of the embodiment of the present invention 1.
Fig. 7 is the image synthesizer structured flowchart of the embodiment of the present invention 2.
Fig. 8 is the image synthesis unit structured flowchart of the embodiment of the present invention 2.
Fig. 9 is the tone mapping block structured flowchart of the embodiment of the present invention 2.
Embodiment
With reference to embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are unlimited
In this.
Embodiment 1：
Present embodiments provide a kind of image combining method, its image of shooting is synthesized based on HDR principle into
Row improvement, there is more details, the image of more preferable light condition to obtain one.
As shown in figure 1, the image combining method of the present embodiment comprises the following steps：
S101, the image for gathering three different exposure parameters
If the present embodiment considers the image of two different exposure parameters of collection, effect can be weaker, and gathers four
Or more different exposure parameters image, in shooting process, caused displacement is too big, have impact on follow-up amendment, therefore certainly
Surely the image of three different exposure parameters, the respectively image of normal exposure parameter, deficient exposure image and overexposure image are gathered.
Because the exposure parameter of different mobile terminal (such as smart mobile phone) built-in camera is different, even if exposure parameter phase
Together, when shooting environmental changes, the exposure effect of image can be also influenceed, therefore the present embodiment is under identical shooting environmental, it is sharp
The image of three different exposure parameters, the ring when exposure parameter of first image is shooting are rapidly shot with same mobile terminal
The exposure parameter in border, the image of the image of the exposure parameter as normal exposure parameter, as shown in Figure 2 a；The exposure of second image
Just regulation downwards obtains owing to expose image on the basis of normal exposure parameter, it is preferable that adjusts 2EV (- 2EV) downwards and obtains owing exposure
Image, as shown in Figure 2 b；The exposure of second image is to be adjusted up obtaining overexposure image on the basis of normal exposure parameter, excellent
Selection of land, it is adjusted up 2EV (+2EV) and obtains overexposure image, as shown in Figure 2 c.
S102, based on HDR principle the image of three different exposure parameters is synthesized, obtain high dynamic range
Enclose image (High-Dynamic Range image, abbreviation HDRI)
As shown in figure 3, step S102 is specifically included：
S1021, the Pixel-level of the image of three different exposure parameters is extended
Mobile terminal uses the display mode of 8bit (rgb signal transmission), this is just mostly in display image at present
The image pixel that image level is only able to display 0~255 this 256 levels is result in, and in actual scene, it is most bright and most dark
Luminance difference has reached 10 away from being the pixel that is far longer than 256 levels, in real really brightness level difference8, so in movement
Terminal can eliminate the pixel beyond 256 levels when showing.
In order to which more details can be retained in image compression process, by the image of above-mentioned three different exposure parameters
Pixel-level is extended, and is specially：By each pixel (2 of three images8) all it is multiplied by 28~264, reaching each pixel can hold
Receive 216~272The pixel of individual level, the present embodiment is in order to adapt to the performance of most of mobile terminal, each pixel of three images
(28) it is multiplied by 224, i.e., each pixel, which reaches, can accommodate 232The pixel of individual level.
S1022, the average value for taking the pixel value after the image spreading of three different exposure parameters, obtain HDR figure
Picture
Pixel value after the image spreading of three different exposure parameters is overlapped, then divided by amount of images (i.e. 3), ask
Go out average value, this makes it possible to obtain one while there are the high dynamic range images of multi-level monochrome information, the high dynamic range
Image is enclosed for an image for putting up near-nature forest illumination.
S103, tone mapping is carried out to high dynamic range images, re-compressed the pixel of high dynamic range images
High dynamic range images are obtained afterwards, it is necessary to be re-compressed to its pixel, returning to it can exist again
The level shown on mobile terminal, this just needs to carry out tone mapping (Tone Mapping) to image, makes it at utmost
Upper reservation details.
Due to the limitation of mobile terminal built-in camera, acquired image can not obtain accurate exposure parameter, also
It can not go to fit the tone mapping that accurate camera response curve removes progress image, so using new tone mapping side here
Method goes to compress high dynamic range images.
As shown in figure 4, step S103 is specifically included：
S1031, the pixel grid for building in whole high dynamic range images multiple 3*3
3*3 pixel grid refer in center pixel grid and be centered around its surrounding eight grids composition, such as
Shown in Fig. 5, by taking two of which 3*3 pixel grid as an example, the center pixel grid of 3*3 pixel grid is A pixel sides
Lattice, A pixels grid form nine grids together with eight pixel grids for being centered around its surrounding, another 3*3 pixel grid
Center pixel grid is B pixel grids, and B pixels grid forms nine grids together with eight pixel grids for being centered around its surrounding.
S1032, the pixel grid for each 3*3, by the pixel of center pixel grid respectively with being centered around the eight of surrounding
The pixel of individual pixel grid is compared
In this step, with A pixels grid and eight pixel grids for being centered around its surrounding, and B pixel grids are with enclosing
It is wound on exemplified by eight pixel grids of its surrounding, by the pixel of A pixel grids and eight pixel grids for being centered around its surrounding
Pixel is compared, and by the pixel of B pixel grids compared with the pixel of eight pixel grids for being centered around its surrounding.
S1033, according to comparative result, when pixel in eight pixel grids for be centered around surrounding and the picture of center pixel grid
During the different pixel grid quantity more than two of element, center pixel grid is judged as marginal information；Otherwise, by center pixel side
Lattice are judged as general information
It is centered around the pixel grid that pixel is different from the pixel of center pixel grid in eight pixel grids of surrounding, this reality
Example is applied to be defined as：It is centered around the pixel that pixel in eight pixel grids of surrounding is more than the pixel of m times of center pixel grid
Grid, or it is centered around the pixel grid that pixel in eight pixel grids of surrounding is less than the pixel of n times of center pixel grid；Its
In, 1<m<1.2,0.8<n<1, such as m value can take 1.02,1.05,1.08,1.1,1.12,1.15,1.18 etc., n value can
To take 0.82,0.85,0.88,0.9,0.92,0.95,0.98 etc., wherein m to take 1.1, n to take 0.9 optimal value obtained for experiment.
Exemplified by by A pixels grid and being centered around eight pixel grids of its surrounding, eight of A pixel grid surroundings are centered around
In pixel grid, it is more than the pixel of 1.1 times of A pixel grids, or less than 0.9 times A picture if there is the pixel of some pixel grid
The pixel of plain grid, then it is assumed that the pixel of the pixel grid is different from the pixel of A pixel grids, counts these pixel number of squares
Amount, as shown in figure 5, in eight pixel grids, there is that the pixel of five pixel grids is different from the pixel of A pixel grids, due to
The quantity more than two of grid, therefore A pixel grids are judged as marginal information, in order to retain more image details, edge
Information is without processing.
Exemplified by by B pixels grid and being centered around eight pixel grids of its surrounding, eight of B pixel grid surroundings are centered around
In pixel grid, it is more than the pixel of 1.1 times of B pixel grids, or less than 0.9 times B picture if there is the pixel of some pixel grid
The pixel of plain grid, then it is assumed that the pixel of the pixel grid is different from the pixel of B pixel grids, counts these pixel number of squares
Amount, as shown in figure 5, in eight pixel grids, the pixel of only one pixel grid is different from the pixel of B pixel grids, by
Two are less than in the quantity of grid, therefore B pixel grids are judged as general information.
S1034, the pixel to all center pixel grids for being judged as general information carry out mapping processing, make high dynamic range
The pixel for enclosing image is re-compressed
Step S1034, is specifically included：
The mapping value of the pixel of all center pixel grids for being judged as general information is calculated, it is as follows：
F (x, y)=ln (p (x, y))/ln (cl)-ln (p)/ln (cl) (1)
Wherein, p (x, y) is the pixel of eight pixel grids of 3*3 pixel grid surroundings, and p is 3*3 pixel sides center of a lattice
The pixel of pixel grid, cl are reduced parameter (being arranged to 5 based on experience value), and f (x, y) is the pixel-map of 3*3 pixel grids
Value；
The weights of all center pixel grids for being judged as general information are calculated, it is as follows：
Wherein, w (x, y) is the pixel weights of 3*3 pixel grids；
Mapping value f (x, y) after calculating and weight w (x, y) are substituted into following formula：
F'(x, y)=f (x, y) * w (x, y) (3)
The f'(x that will be calculated, y) substitute into following formula：
Wm=∑s f'(x, y)/∑ w (x, y) (4)
Wherein, wm is a numerical value in computing；
The wm being calculated is substituted into following formula：
L (x, y)=e(wm+(p(x,y)/log(cl)))*log(cl) (5)
Wherein, l (x, y) is pixel value；
By the calculating of formula (5), the pixel value l (x, y) of final image is obtained, in order to allow pixel value can be in mobile terminal
In show, pixel value l (x, y) is normalized in 0~255 level, that is, the picture by 3*3 pixels grid after mapping
Element value is filled back in original 3*3 pixel grids, and the image pixel after compression is the low-dynamic range for being adapted to mobile terminal to show
(Low-DynamicRange) image, final effect with artwork (i.e. Fig. 2 a) as shown in fig. 6, contrast, when reducing shooting image
Noise caused by because of the lighting issues of environment, while solve the skew in image processing process on Color Channel, both improved
Image interior details, remain image edge detailss again.
Embodiment 2：
As shown in fig. 7, present embodiments provide a kind of image synthesizer based on HDR principle, described device
It is as follows including image capture module 701, image synthesis unit 702 and tone mapping block 703, the concrete function of modules：
Described image acquisition module 701, for gathering the image of multiple different exposure parameters.
Described image synthesis module 702, for being entered the image of multiple different exposure parameters based on HDR principle
Row synthesis, obtains high dynamic range images, the structure of the module is as shown in figure 8, specifically include：
Pixel-level expanding element 7021, for the Pixel-level of the image of multiple different exposure parameters to be extended, specifically
For：Each pixel in the image of multiple different exposure parameters is multiplied by 28~264, 2 can be accommodated by reaching each pixel16~
272The pixel of individual level；
Averaging unit 7022, the average value of the pixel value after image spreading for taking multiple different exposure parameters, obtain
High dynamic range images.
The tone mapping block 703, for carrying out tone mapping to high dynamic range images, make high dynamic range images
Pixel re-compressed, the structure of the module is as shown in figure 9, specifically include：
Pixel grid construction unit 7031, for building multiple 3*3 pixel grid in whole high dynamic range images；
Comparing unit 7032, for the pixel grid for each 3*3, by the pixel of center pixel grid respectively with around
It is compared in the pixel of eight pixel grids of surrounding；
Judging unit 7033, for according to comparative result, when pixel and center in eight pixel grids for be centered around surrounding
During the different pixel grid quantity more than two of the pixel of pixel grid, center pixel grid is judged as marginal information；Otherwise,
Center pixel grid is judged as general information；
It is whether identical with the pixel of center pixel grid to be centered around the pixel of eight pixel grids of surrounding, using following
Judgment mode：
A, be centered around in eight pixel grids of surrounding, if there is some pixel grid pixel be more than m (m for setting
Value, 1<m<1.2) pixel of times center pixel grid, then the pixel of the pixel grid is different from the pixel of center pixel grid；
B, be centered around in eight pixel grids of surrounding, if there is some pixel grid pixel be less than n (n for setting
Value, 0.8<n<1) pixel of times center pixel grid, then the pixel of the pixel grid is different from the pixel of center pixel grid；
C, the situation beyond above-mentioned a and b, the i.e. pixel of some pixel grid are less than or equal to m times of center pixel grid
Pixel, while be more than or equal to the pixel of n times of center pixel grid again, the then pixel of the pixel grid and center pixel grid
Pixel is identical.
Map unit 7034, for being carried out to the pixel of all center pixel grids for being judged as general information at mapping
Reason, is re-compressed the pixel of high dynamic range images, specifically included：
The mapping value of the pixel of all center pixel grids for being judged as general information is calculated, it is as follows：
F (x, y)=ln (p (x, y))/ln (cl)-ln (p)/ln (cl)
Wherein, p (x, y) is the pixel of eight pixel grids of 3*3 pixel grid surroundings, and p is 3*3 pixel sides center of a lattice
The pixel of pixel grid, cl are reduced parameter, and f (x, y) is the pixel-map value of 3*3 pixel grids；
The weights of all center pixel grids for being judged as general information are calculated, it is as follows：
Wherein, w (x, y) is the pixel weights of 3*3 pixel grids；
Mapping value f (x, y) after calculating and weight w (x, y) are substituted into following formula：
F'(x, y)=f (x, y) * w (x, y)
The f'(x that will be calculated, y) substitute into following formula：
Wm=∑s f'(x, y)/∑ w (x, y)
Wherein, wm is a numerical value in computing；
The wm being calculated is substituted into following formula：
L (x, y)=e(wm+(p(x,y)/log(cl)))*log(cl)
Wherein, l (x, y) is pixel value；
Pixel value l (x, y) is normalized in 0~255 level, that is, the pixel by 3*3 pixels grid after mapping
Value is filled back in original 3*3 pixel grids.
Herein it should be noted that the device of the present embodiment only carried out with the division of above-mentioned each functional module for example,
In actual applications, it can be completed, i.e., drawn internal structure by different functional modules as needed and by above-mentioned function distribution
It is divided into different functional modules, to complete all or part of function described above.
Embodiment 3：
A kind of mobile terminal is present embodiments provided, including processor and memory, memory storage have one or more
Program, during the program of computing device memory storage, realize following operation：
Gather the image of multiple different exposure parameters；
The image of multiple different exposure parameters is synthesized based on HDR principle, obtains HDR figure
Picture；
Tone mapping is carried out to high dynamic range images, is re-compressed the pixel of high dynamic range images.
Mobile terminal described in the present embodiment can be smart mobile phone, PDA handheld terminals, tablet personal computer or other have
Shooting and the hand held terminal unit of display function.
In summary, the image of the invention by gathering multiple different exposure parameters, will be more based on HDR principle
The image of Zhang Butong exposure parameters is synthesized, and the image of synthesis produces when reducing shooting image because of the lighting issues of environment
Noise, while solve the skew in image processing process on Color Channel, then the high dynamic range images of acquisition are carried out
Tone maps, and is re-compressed the pixel of high dynamic range images, can be shown on mobile terminals again with returning to
Level, and retain details to the full extent.
It is described above, patent preferred embodiment only of the present invention, but the protection domain of patent of the present invention is not limited to
This, such as the image of two, four or more different exposure parameters of collection synthesize same realization, it is any to be familiar with this technology neck
The technical staff in domain adds in the scope disclosed in patent of the present invention according to the technical scheme of patent of the present invention and its inventive concept
With equivalent substitution or change, the protection domain of patent of the present invention is belonged to.
Claims (13)
- A kind of 1. image combining method based on HDR principle, it is characterised in that：Methods described includes：Gather the image of multiple different exposure parameters；The image of multiple different exposure parameters is synthesized based on HDR principle, obtains high dynamic range images；Tone mapping is carried out to high dynamic range images, is re-compressed the pixel of high dynamic range images.
- A kind of 2. image combining method based on HDR principle according to claim 1, it is characterised in that：It is described The image of multiple different exposure parameters is synthesized based on HDR principle, obtains high dynamic range images, specific bag Include：The Pixel-level of the image of multiple different exposure parameters is extended；The average value of the pixel value after the image spreading of multiple different exposure parameters is taken, obtains high dynamic range images.
- A kind of 3. image combining method based on HDR principle according to claim 2, it is characterised in that：It is described Pixel-level in the image of multiple different exposure parameters is extended, is specially：Each pixel in the image of multiple different exposure parameters is multiplied by 28~264, 2 can be accommodated by reaching each pixel16~ 272The pixel of individual level.
- A kind of 4. image combining method based on HDR principle according to claim 1, it is characterised in that：To height Dynamic image carries out tone mapping, is re-compressed the pixel of high dynamic range images, specifically included：Multiple 3*3 pixel grid is built in whole high dynamic range images；For each 3*3 pixel grid, by the pixel of center pixel grid respectively with being centered around eight pixel grids of surrounding Pixel be compared；According to comparative result, when the picture different from the pixel of center pixel grid of pixel in eight pixel grids for be centered around surrounding During plain grid quantity more than two, center pixel grid is judged as marginal information；Otherwise, center pixel grid is judged as general Communication breath；Mapping processing is carried out to the pixel of all center pixel grids for being judged as general information, makes the picture of high dynamic range images Element is re-compressed.
- A kind of 5. image combining method based on HDR principle according to claim 4, it is characterised in that：It is described The pixel grid that pixel is different from the pixel of center pixel grid in eight pixel grids of surrounding is centered around to refer to：It is centered around the pixel grid that pixel in eight pixel grids of surrounding is more than the pixel of m times of center pixel grid；Wherein, 1< m<1.2；Or it is centered around the pixel grid that pixel in eight pixel grids of surrounding is less than the pixel of n times of center pixel grid；Wherein, 0.8<n<1。
- A kind of 6. image combining method based on HDR principle according to claim 4, it is characterised in that：It is described Mapping processing is carried out to the pixel of all center pixel grids for being judged as general information, enters the pixel of high dynamic range images Row re-compresses, and specifically includes：The mapping value of the pixel of all center pixel grids for being judged as general information is calculated, it is as follows：F (x, y)=ln (p (x, y))/ln (cl)-ln (p)/ln (cl)Wherein, p (x, y) is the pixel of eight pixel grids of 3*3 pixel grid surroundings, and p is the center pixel of 3*3 pixel grids The pixel of grid, cl are reduced parameter, and f (x, y) is the pixel-map value of 3*3 pixel grids；The weights of all center pixel grids for being judged as general information are calculated, it is as follows：<mrow> <mi>w</mi> <mrow> <mo>(</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo>)</mo> </mrow> <mo>=</mo> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mo>|</mo> <mi>f</mi> <mrow> <mo>(</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo>)</mo> </mrow> <msup> <mo>|</mo> <mrow> <mn>5</mn> <mo>*</mo> <mi>c</mi> <mi>l</mi> </mrow> </msup> </mrow> </msup> </mrow> 1Wherein, w (x, y) is the pixel weights of 3*3 pixel grids；Mapping value f (x, y) after calculating and weight w (x, y) are substituted into following formula：F'(x, y)=f (x, y) * w (x, y)The f'(x that will be calculated, y) substitute into following formula：Wm=∑s f'(x, y)/∑ w (x, y)Wherein, wm is a numerical value in computing；The wm being calculated is substituted into following formula：L (x, y)=e(wm+(p(x,y)/log(cl)))*log(cl)Wherein, l (x, y) is pixel value；Pixel value l (x, y) is normalized in 0~255 level.
- A kind of 7. image synthesizer based on HDR principle, it is characterised in that：Described device includes：Image capture module, for gathering the image of multiple different exposure parameters；Image synthesis unit, for being synthesized the image of multiple different exposure parameters based on HDR principle, obtain High dynamic range images；Tone mapping block, for carrying out tone mapping to high dynamic range images, carry out the pixel of high dynamic range images Re-compress.
- A kind of 8. image synthesizer based on HDR principle according to claim 7, it is characterised in that：It is described Image synthesis unit, specifically include：Pixel-level expanding element, for the Pixel-level of the image of multiple different exposure parameters to be extended；Averaging unit, the average value of the pixel value after image spreading for taking multiple different exposure parameters, obtain high dynamic range Enclose image.
- A kind of 9. image synthesizer based on HDR principle according to claim 8, it is characterised in that：It is described Pixel-level expanding element, it is specially：For each pixel in the image of multiple different exposure parameters to be multiplied by into 28~264, reaching each pixel can accommodate 216~272The pixel of individual level.
- A kind of 10. image synthesizer based on HDR principle according to claim 7, it is characterised in that：Institute Tone mapping block is stated, is specifically included：Pixel grid construction unit, for building multiple 3*3 pixel grid in whole high dynamic range images；Comparing unit, for the pixel grid for each 3*3, by the pixel of center pixel grid respectively with being centered around surrounding The pixel of eight pixel grids is compared；Judging unit, for according to comparative result, when pixel in eight pixel grids for be centered around surrounding and center pixel grid Pixel different pixel grid quantity more than two when, center pixel grid is judged as marginal information；Otherwise, by middle imago Plain grid is judged as general information；Map unit, for carrying out mapping processing to the pixel of all center pixel grids for being judged as general information, make high dynamic The pixel of state range image is re-compressed.
- A kind of 11. image synthesizer based on HDR principle according to claim 10, it is characterised in that：Institute The pixel grid that pixel is different from the pixel of center pixel grid in eight pixel grids for be centered around surrounding is stated to refer to：It is centered around the pixel grid that pixel in eight pixel grids of surrounding is more than the pixel of m times of center pixel grid；Wherein, 1< m<1.2；Or it is centered around the pixel grid that pixel in eight pixel grids of surrounding is less than the pixel of n times of center pixel grid；Wherein, 0.8<n<1。
- A kind of 12. image synthesizer based on HDR principle according to claim 10, it is characterised in that：Institute State in map unit, tone mapping processing is carried out to all center pixel grids for being judged as general information, makes HDR The pixel of image is re-compressed, and is specifically included：The mapping value of the pixel of all center pixel grids for being judged as general information is calculated, it is as follows：F (x, y)=ln (p (x, y))/ln (cl)-ln (p)/ln (cl)Wherein, p (x, y) is the pixel of eight pixel grids of 3*3 pixel grid surroundings, and p is the center pixel of 3*3 pixel grids The pixel of grid, cl are reduced parameter, and f (x, y) is the pixel-map value of 3*3 pixel grids；The weights of all center pixel grids for being judged as general information are calculated, it is as follows：<mrow> <mi>w</mi> <mrow> <mo>(</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo>)</mo> </mrow> <mo>=</mo> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mo>|</mo> <mi>f</mi> <mrow> <mo>(</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo>)</mo> </mrow> <msup> <mo>|</mo> <mrow> <mn>5</mn> <mo>*</mo> <mi>c</mi> <mi>l</mi> </mrow> </msup> </mrow> </msup> </mrow>Wherein, w (x, y) is the pixel weights of 3*3 pixel grids；Mapping value f (x, y) after calculating and weight w (x, y) are substituted into following formula：F'(x, y)=f (x, y) * w (x, y)The f'(x that will be calculated, y) substitute into following formula：Wm=∑s f'(x, y)/∑ w (x, y)Wherein, wm is a numerical value in computing；The wm being calculated is substituted into following formula：L (x, y)=e(wm+(p(x,y)/log(cl)))*log(cl)Wherein, l (x, y) is pixel value；Pixel value l (x, y) is normalized in 0~255 level.
- 13. a kind of mobile terminal, including processor and the memory for storing processor executable program, its feature exist In：During the program of the computing device memory storage, following operation is realized：Gather the image of multiple different exposure parameters；The image of multiple different exposure parameters is synthesized based on HDR principle, obtains high dynamic range images；Tone mapping is carried out to high dynamic range images, is re-compressed the pixel of high dynamic range images.
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