Background technology
Estimation is a part crucial in Video coding, is based primarily upon Block- matching and layering interpolation realizes that high-precision is transported
The solution of dynamic vector, and then release the redundancy of video in time.Wherein, Block- matching refers on reference frame according to corresponding
It is searched for criterion and obtains corresponding blocks and optimal matching blocks.And it refers to being asked by the interpolation calculation of multistage different accuracy to be layered interpolation
Solve the motion vector of different accuracy.Whether interpolation calculation is used according to estimation, estimation can be divided into whole pixel
Estimation and be divided to pixel motion estimate two parts.Although estimation can largely compress video, its
The complexity of body exacerbates binary encoding and takes, and the introducing that pixel motion is estimated especially is divided further to exacerbate the problem.
And the complexity for dividing pixel motion to estimate is concentrated mainly on its a large amount of interpolation calculation, particularly, in HEVC (high property
Can Video coding) in use the interpolation filter compared to H.264 more tap numbers.
For this purpose, some researchers attempt to get around complicated interpolation calculation process by establishing model of error estimate to add
Pixel motion is divided to estimate soon.Its main policies is estimated to establish second order error using best whole pixel and its neighbouring whole pixel
Curved surface, the minimum point quickening by solving second order error curved surface approach and most preferably divide pixel, to avoid excessive interpolation with
Search for matching process.Certainly, the premise that their strategies prove effective is to calculate the operation cost of minimum compared to interpolation and search matching
Process is much smaller.Wherein, more typically there are Salih Dikbas et al. (Salih Dikbas, Tarik Arici, Yucel
Altunbasak.Fast motion estimation with interpolation-freesub-sample accuracy
[J].Circuits and Systems for Video Technology,IEEE Transactions on,2010,20
(7):1047-1051.) carried second order error estimation model and some other researcher (Jing-Fu Chang, Jin-
Jang Leou.A quadratic prediction based fractional-pixel motion estimation
algorithm for H.264[J].Journal of Visual Communication and Image
Representation,2006,17(5):1074-1089.) " degeneration " second order error that its second order model simplification is formed is estimated
Model.Theirs the experimental results showed that, by model estimate method can largely reduce encoder complexity.
Other than establishing model of error estimate, threshold value control means (Tsuyoshi Sotetsumoto, Tian Song,
Takashi Shimamoto.Low complexity algorithm for sub-pixel motion estimation of
HEVC [C] .IEEE, 2013:1-4) also be used to reduce divides pixel motion to estimate complexity.
However, other researchers (Tokunbo Ogunfunmi, Obianuju Ndili, Pavel
Arnaudov.On low power fractional motion estimation algorithms for H.264[C]
.IEEE, 2012:The complexity of point pixel motion estimation 103-108) is primarily focused on in hard-wired influence, side
Interpolation Process is improved again to accelerate a point hardware realization for pixel motion estimation.
Invention content
In view of the deficiencies of the prior art, the present invention proposes a kind of HEVC points of pixels being layered interpolation based on low complex degree to transport
Dynamic method of estimation.
The present invention provides a kind of HEVC being layered interpolation based on low complex degree to divide pixel motion estimating method, this method packet
It includes:
Step 1:Area-of-interest is initialized on whole pixel precision;
Step 2:Pixel original value is converted into the median of corresponding integer by linear transformation;
Step 3:1/2 point of pixel carries out interpolation calculation using 8 tap filters;Specially:Following 8 are utilized to whole pixel
Tap FIR filters carry out filtering interpolation:{ -1,4, -11,40,40, -11,4, -1 } 1/2 point of pixel is obtained.
Step 4:Linear inversion obtains 1/2 image element interpolation filter result of original value;
Step 5:Motion vector refinement is to 1/2 point of pixel precision;
Step 6:1/2 point of pixel median in vertical direction carries out interpolation calculation using 6 tap filters;Specific packet
It includes:1/2 point of pixel on whole pixel and horizontal direction is filtered using following 6 tap FIR filters simultaneously:{1,-
5,20,20,-5,1}。
Step 7:1/2 point of pixel median is obtained according to different tap filterings, is solved among 1/4 point of pixel using mean value
Value;
Step 8:Inverse transformation is carried out to 1/4 point of pixel median and obtains final 1/4 image element interpolation result;Motion vector
It is refined to 1/4 point of pixel precision.
Institute's extracting method can preferably take into account the complexity and code efficiency of software and hardware realization.
The 1/2 point of pixel median obtained according to different tap filterings in step 7 solves 1/4 point of pixel using its mean value
Median;1/2 point of pixel median that wherein different tap filterings obtain refers specifically to 1/2 point of pixel median in vertical direction and adopts
With step 6 result of calculation, 1/2 point of pixel median uses step 3 result of calculation in horizontal direction.
Advantageous effect:Coding rate is improved to accelerate to divide pixel motion estimation procedure, and then promotes encoder to real-time
The satisfaction of code requirement.
Specific implementation mode
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation describes, it is clear that described embodiment is a part of the embodiment of the present invention, rather than whole embodiments.Based on this hair
Embodiment in bright, the every other reality that those of ordinary skill in the art are obtained without making creative work
Example is applied, the scope of protection of the invention should be all belonged to.
As shown in Figure 1, a kind of HEVC being layered interpolation based on low complex degree divides pixel motion estimating method, this method packet
It includes:
Step 1:Area-of-interest is initialized on whole pixel precision;
Step 2:Pixel original value is converted into the median of corresponding integer by linear transformation;
Step 3:1/2 point of pixel carries out interpolation calculation using 8 tap filters;
Step 4:Linear inversion obtains 1/2 image element interpolation filter result of original value;
Step 5:Motion vector refinement is to 1/2 point of pixel precision;
Step 6:Interpolation calculation is carried out again using 6 tap filters;
Step 7:1/2 point of pixel median is obtained according to different tap filterings, is solved among 1/4 point of pixel using mean value
Value;
Step 8:Inverse transformation is carried out to 1/4 point of pixel median and obtains final 1/4 image element interpolation result;Motion vector
It is refined to 1/4 point of pixel precision.
Fig. 2 shows different accuracy location of pixels relationships.As shown in Fig. 2, whole pixel is stored in memory module (0,0)
In, it is stored in memory module (0,2) with 1/2 point of pixel in whole pixel same level direction, it is same vertical with whole pixel
1/2 point of pixel in direction is stored in memory module (2,0), and remaining 1/2 point of pixel is stored in memory module (2,2)
In.
Fig. 3 shows 1/2 image element interpolation module diagram.As shown in figure 3, this method includes:Linear transformation, Ke Yitong
It crosses the operations such as displacement, addition and realizes that rapid translating is used for intermediate computations at corresponding integer data;
For subsequently calculating in direct copying whole pixel deposit caching 0.
Calculating is filtered in the horizontal direction using 8 tap FIR filters in HEVC to whole pixel and is stored in result slow
It deposits in 2.
It is copied directly in memory module (0,0) after value in caching 0 is carried out corresponding linear inversion.
Vertical direction filtering is carried out using HEVC8 tap FIR filters to the value in caching 0 and is carried out result corresponding
Linear inversion is stored in memory module (2,0).
It is copied directly in memory module (0,2) after value in caching 2 is carried out corresponding linear inversion.
Similarly, to caching 2 in value using HEVC8 tap FIR filters carry out vertical direction filtering and by result into
In the corresponding linear inversion deposit memory module (2,2) of row.
Estimate to obtain motion vector and 1/2 image element interpolation as a result, being refined to motion vector according to whole pixel motion
Obtain the motion vector of 1/2 point of pixel precision.
Fig. 4 shows 1/4 image element interpolation module diagram.As shown in figure 4, this method includes:
The value of caching 0 is filtered using 6 tap FIR filters H.264 and is stored in result slow in vertical direction
It deposits in 1.
Similarly, the value of caching 2 is filtered in vertical direction using 6 tap FIR filters H.264 and by result
In deposit caching 3.
According to the result of calculation of caching 0,1,2,3,1/4 point of pixel is calculated separately by the way of the solution of adjacency mean value
Value, and by final calculation result carry out corresponding linear inversion be stored in respectively memory module (3,0), (1,1), (0,1),
(1,0), (3,1), (0,3), (1,3), (2,1), (3,2), (3,3), (2,3), (1,2).
Motion vector and 1/4 image element interpolation are obtained as a result, carrying out essence to motion vector according to 1/2 point of pixel motion estimation
Refining obtains the motion vector of 1/4 point of pixel precision.
The method of the embodiment of the present invention is mainly used in HEVC coding standards, divides pixel motion to estimate for improving it
Complexity, meanwhile, ensure coding compression performance.
Those of ordinary skill in the art may realize that each method steps in conjunction with described in the embodiments described herein
Rapid and unit, can be realized with electronic hardware, computer software, or a combination of the two, in order to clearly demonstrate hardware and soft
The interchangeability of part, the step of generally describing each embodiment according to function in the above description and composition.These
Function is implemented in hardware or software actually, depends on the specific application and design constraint of technical solution.Ability
Domain those of ordinary skill can use different methods to achieve the described function each specific application, but this reality
Now it should not be considered as beyond the scope of the present invention.
Method or step described in conjunction with the examples disclosed in this document can use the software journey that hardware, processor execute
The combination of sequence or the two is implemented.Software program can be placed in random access memory (RAM), memory, read-only memory (ROM),
Institute is public in electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or technical field
In any other form of storage medium known.
Although by reference to attached drawing and combining the mode of preferred embodiment to the present invention have been described in detail, the present invention
It is not limited to this.Without departing from the spirit and substance of the premise in the present invention, those of ordinary skill in the art can be to the present invention
Embodiment carry out various equivalent modifications or substitutions, and these modifications or substitutions all should be in the covering scope of the present invention.