CN1703093A - System and method for mosquito noise detection and reduction - Google Patents
System and method for mosquito noise detection and reduction Download PDFInfo
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- CN1703093A CN1703093A CN 200510074519 CN200510074519A CN1703093A CN 1703093 A CN1703093 A CN 1703093A CN 200510074519 CN200510074519 CN 200510074519 CN 200510074519 A CN200510074519 A CN 200510074519A CN 1703093 A CN1703093 A CN 1703093A
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Abstract
A system and method for detecting and reducing mosquito noise are disclosed. Areas within a frame with mosquito noise are detected by calculating the variance of the luminance blocks in a macroblock, determining the minimum variance of the macroblock luminance blocks, and comparing the minimum variance to a mosquito noise threshold. If the minimum variance is greater than the mosquito noise threshold, then the macroblock is considered a high activity macroblock and the corresponding macroblock bit in the frame bitmap is set. If the minimum variance is less than or equal to the mosquito noise threshold, then the macroblock is considered a low activity macroblock, and the corresponding macroblock bit in the frame bit map is cleared. If the current macroblock bit is set in the corresponding frame bitmap or if at least one of its adjacent eight macroblock bits is set in the corresponding frame bitmap, then the current macroblock requires mosquito noise reduction. Mosquito noise in the current macroblock is reduced by reducing the original bit rate quantizer scale to achieve the target of reducing the mosquito noise.
Description
Technical field
The present invention relates to video compression technology, relate in particular to a kind of digital video coding system and method that can detect and reduce mosquito noise (mosquito noise).
Background technology
Nowadays digital video product and service and the storage of internet video data flow and indexing unit are found everywhere on market.Because the restriction of digital signal storage capacity and network transmission bandwidth, digital video signal compress technique are the key technologies in digital video storage and the transmission.Therefore a lot of digital video signal compressions and coding standard have been issued.These standard codes specific encoding digital video signals form and how with this signal decoding so that it is shown to spectators.
ISO/IEC international standard 13818 (being commonly referred to as the MPEG-2 form) is wherein a kind of.The MPEG-2 form is formulated by Motion Picture Experts Group (MPEG), in " the ITU-T proposed standard H.262 " and " the general coding-second portion of ISO/IEC13818-2:1996 information technology-moving image and related audio: video " detailed description is arranged, this document is also all quoted by the application.Although Moving Picture Experts Group-2 has only stipulated to generate the general coding method and the grammer of the bit stream that meets MPEG-2, this standard allows to carry out many variations, to be applicable to multiple different application and service, for example, desktop video distribution, video conference, digital storage media, television broadcasting.Therefore, how the digital video signal of original, uncompressed form is converted on the specific coded format this point, MPEG-2 has given very big free right of disposal.That is to say that coding method is not strictly to be defined in permission to trade off between the computing capability of video quality, compression ratio, encoder this some.Therefore, various encoding digital video signals device and multiple encoding digital video signals method have appearred.
The various noise artefacts relevant with the MPEG vision signal are known in the industry, for example, and wherein a kind of " flying mosquito " noise (' mosquito ' noise) that is called.Mosquito noise appears at visual rapid variation edge (sharp edge) on every side because of the decay of high frequency conversion coefficient produces.The mosquito noise artefact is similar to a group mosquito and appears at jobbie effect on every side.Therefore in the MPEG video system, need a kind of method and system that detects and reduce mosquito noise.
For a person skilled in the art, by legacy system and the present invention's (will introduce at the application's further part) are compared, other limitation and the shortcoming of existing conventional method are conspicuous.
Summary of the invention
The present invention relates to a kind of system and method that detects and reduce mosquito noise.The frame inner region that contains mosquito noise can detect by the following method: the difference of luminance block in the computing macro block; Determine the minimum difference of luminance block in the macro block; This minimum difference and mosquito noise threshold value are compared.If described minimum difference is greater than the mosquito noise threshold value, this macro block is regarded as high activity macro block, and the respective macroblock position in the framing bit figure is by the value of putting.If described minimum difference is less than or equal to the mosquito noise threshold value, this macro block is regarded as low activity macro block, and the respective macroblock position in the framing bit figure is cleared.If the current macro position in the corresponding framing bit figure is by the value of putting, perhaps at least one in its 8 adjacent macro block positions is by the value of putting, and then current macro need reduce mosquito noise.Current macro the right and following macro block belong to the position setting/zero clearing of former frame.The reduction of mosquito noise realizes by reducing initial bit rate quantization scale code.Mosquito noise of the present invention detects and reduces system and method with unidirectional (single pass) coded system, carries out with grating scanning mode.In other words, mosquito noise of the present invention detects and from left to right macro block of a macro block, the delegation's execution from top to bottom of reduction system with meeting delegation.
One aspect of the present invention provides the system that detects mosquito noise in a kind of video system, comprising: the macroblock analysis device is used for determining whether the current macro in the frame is high activity macro block; The position is provided with device/zero clearing device, is used for whether the indication current macro is high activity macro block on framing bit figure; The framing bit figure analyzer is used for determining by calculating framing bit figure whether current macro needs to reduce mosquito noise.If the current macro position in the corresponding framing bit figure is by the value of putting, perhaps at least one is by the value of putting in its 8 adjacent macro block positions, and then current macro need reduce mosquito noise.The mosquito noise damper reaches the purpose that reduces mosquito noise by reducing initial bit rate quantization scale.
Another aspect of the present invention provides a kind of method that detects and reduce mosquito noise in the frame of video, comprises the steps: to determine whether the current macro in the present frame is high activity macro block; Whether the indication current macro is high activity macro block on framing bit figure; Calculate described framing bit figure to determine whether current macro needs to reduce mosquito noise; Reduce mosquito noise in the present frame by reducing initial bit rate quantization scale.
According to an aspect of the present invention, provide a kind of video coding system, comprising:
Input unit is used for receiving video signals, and described vision signal comprises a plurality of frames;
The mosquito noise detector is used to detect present frame and whether contains mosquito noise.
Preferably, described video coding system further comprises the mosquito noise damper, is used for reducing mosquito noise by reducing initial bit rate quantization scale.
Preferably, described mosquito noise detector further comprises:
The macroblock analysis device is used for determining whether the current macro in the frame is high activity macro block;
Whether the position is provided with device/zero clearing device, is used for the position of current macro in the marker frame bitmap, be high activity macro block with the indication current macro.
Preferably, described video coding system also further comprises:
The framing bit figure analyzer is used to calculate framing bit figure and determines whether current macro needs to reduce mosquito noise.
Preferably, described high activity macro block is meant the macro block with the difference that is higher than the mosquito noise threshold value.
Preferably, described macroblock analysis device determines by the following method whether current macro is high activity macro block:
Calculate the difference of each luminance block in the current macro;
Determine the minimum difference of luminance block;
Described minimum difference and mosquito noise threshold value are compared.
Preferably, if current macro is detected as high activity macro block, institute's rheme is provided with device/zero clearing device to macro block position value in the framing bit figure.
Preferably, if current macro is not high activity macro block, institute's rheme is provided with device/zero clearing device to the macro block position zero clearing in the framing bit figure.
Preferably, described mosquito noise threshold value is the logarithm at the end and compares to come it definite with 10 by the minimum difference value of luminance block in the current macro being got with 2.
Preferably, described mosquito noise threshold value approximately is 2
10
According to another aspect of the present invention, provide the system that detects mosquito noise in a kind of video system, comprising:
The macroblock analysis device is used for by determining whether current macro is that high activity macro block determines whether the current macro in the frame contains mosquito noise;
The position is provided with device/zero clearing device, is used for whether the indication current macro is high activity macro block on framing bit figure.
Preferably, described video coding system further comprises:
The framing bit figure analyzer is used for determining by calculating framing bit figure whether current macro needs to reduce mosquito noise.
Preferably, described video coding system further comprises:
The mosquito noise damper is used for reducing mosquito noise by reducing initial bit rate quantization scale.
Preferably, described high activity macro block is meant the macro block with the difference that is higher than the mosquito noise threshold value.
Preferably, described macroblock analysis device determines by the following method whether current macro is high activity macro block:
Calculate the difference of each luminance block in the current macro;
Determine the minimum difference of luminance block;
Described minimum difference and mosquito noise threshold value are compared.
Preferably, described mosquito noise threshold value is the logarithm at the end and compares to come it definite with 10 by the minimum difference of luminance block in the current macro being got with 2.
Preferably, described mosquito noise threshold value approximately is 2
10
Preferably, if current macro is detected as high activity macro block, institute's rheme is provided with device/zero clearing device to the macro block position value in the framing bit figure.
Preferably, if current macro is not high activity macro block, institute's rheme is provided with device/zero clearing device to the macro block position zero clearing in the framing bit figure.
This provides a kind of system that is used to detect and reduce mosquito noise in the video system according to one aspect of the present invention, and described system comprises:
The macroblock analysis device is used for by judging whether current macro is that high activity macro block determines whether the current macro in the frame contains mosquito noise;
The position is provided with device/zero clearing device, is used for whether the indication current macro is high activity macro block on framing bit figure;
The framing bit figure analyzer is used for determining by calculating framing bit figure whether current macro needs to reduce mosquito noise;
The mosquito noise damper is used for reducing mosquito noise by reducing initial bit rate quantization scale.
Preferably, described macroblock analysis device determines by the following method whether current macro is high activity macro block:
Calculate the difference of each luminance block in the current macro;
Determine the minimum difference of luminance block;
Described minimum difference and mosquito noise threshold value are compared.
Preferably, described mosquito noise threshold value is the logarithm at the end and compares to come it definite with 10 by the minimum difference of luminance block in the current macro being got with 2.
Preferably, described mosquito noise threshold value approximately is 2
10
Preferably, if current macro is detected as high activity macro block, institute's rheme is provided with device/zero clearing device to the macro block position value in the framing bit figure.
Preferably, if current macro is not high activity macro block, institute's rheme is provided with device/zero clearing device to the macro block position zero clearing in the framing bit figure.
According to an aspect of the present invention, provide the interior current macro of a kind of definite vision signal whether to contain the method for mosquito noise, said method comprising the steps of:
Determine whether the current macro in the present frame is high activity macro block;
Whether the indication current macro is high activity macro block on framing bit figure.
Preferably, described method further may further comprise the steps:
Determine by calculating framing bit figure whether current macro needs to reduce mosquito noise.
Preferably, described method also further comprises the steps:
Reduce mosquito noise in the current macro by reducing initial bit rate quantization scale.
Preferably, described high activity macro block is meant the macro block with the difference that is higher than the mosquito noise threshold value.
Preferably, described macroblock analysis device determines by the following method whether current macro is high activity macro block:
Calculate the difference of each luminance block in the current macro;
Determine the minimum difference of luminance block;
Described minimum difference and mosquito noise threshold value are compared.
Preferably, described mosquito noise threshold value is the logarithm at the end and compares to come it definite with 10 by the minimum difference of luminance block in the current macro being got with 2.
Preferably, described mosquito noise threshold value approximately is 2
10
Preferably, if current macro is detected as high activity macro block, institute's rheme is provided with device/zero clearing device to the macro block position position in the framing bit figure.
Preferably, if current macro is not high activity macro block, institute's rheme is provided with device/zero clearing device to the macro block position zero clearing in the framing bit figure.
According to an aspect of the present invention, provide the interior current macro of a kind of definite vision signal whether to contain the method for mosquito noise, said method comprising the steps of:
By determining whether current macro is that high activity macro block determines whether the current macro in the present frame contains mosquito noise;
Whether the indication current macro is high activity macro block on framing bit figure;
Calculate framing bit figure to determine whether current macro needs to reduce mosquito noise;
Reduce mosquito noise in the current macro by reducing initial bit rate quantization scale.
Preferably, described macroblock analysis device determines by the following method whether current macro is high activity macro block:
Calculate the difference of each luminance block in the current macro;
Determine the minimum difference of luminance block;
Described minimum difference and mosquito noise threshold value are compared.
Preferably, described mosquito noise threshold value is the logarithm at the end and compares to come it definite with 10 by the minimum difference of luminance block in the current macro being got with 2.
Preferably, described mosquito noise threshold value approximately is 2
10
Preferably, if current macro is detected as high activity macro block, institute's rheme is provided with device/zero clearing device to the macro block position value in the framing bit figure.
Preferably, if current macro is not high activity macro block, institute's rheme is provided with device/zero clearing device to the macro block position zero clearing in the framing bit figure.
In a word, mosquito noise of the present invention detects and reduces method and system and can detect potential mosquito noise zone in the frame, and gives this region allocation than common more bits position, to reach the purpose that reduces mosquito noise.Advantage of the present invention, character of innovation and detailed embodiment will introduce in follow-up specification and accompanying drawing in detail.
Description of drawings
Fig. 1 is the high level block diagram of video encoder according to the preferred embodiment of the invention;
Fig. 2 is the mosquito noise detector according to an embodiment of the invention and block diagram damper;
Fig. 3 is the flow chart that calculates high activity macro block according to an embodiment of the invention;
Fig. 4 determines according to an embodiment of the invention whether macro block is the flow chart of high activity macro block;
Fig. 5 is the flow chart that calculates macro block position among the framing bit figure according to an embodiment of the invention;
Fig. 6 a-6c is implementation step figure according to an embodiment of the invention.
Embodiment
Describe the present invention by preferred embodiment below with reference to accompanying drawing.In order to understand the present invention more all sidedly, below will provide a large amount of concrete introductions.But some or all details even without wherein also can realize the present invention to those skilled in the art significantly.On the other hand, for fear of fuzzy inventive point of the present invention, known program and step are not described in detail in following specification.
The present invention relates to a kind of system and method that detects and reduce mosquito noise.The frame inner region that contains mosquito noise can detect by the following method: the difference of calculating luminance block in the current macro; Determine the minimum difference of luminance block in the current macro; This minimum difference and mosquito noise threshold value are compared.If described minimum difference is greater than the mosquito noise threshold value, this macro block is regarded as high activity macro block, and to the respective macroblock positional value in the framing bit figure.If described minimum difference is less than or equal to the mosquito noise threshold value, this macro block is regarded as low activity macro block, and the respective macroblock position in the framing bit figure is cleared.Calculate framing bit figure then to determine whether current macro needs to reduce mosquito noise.If the current macro position in the corresponding framing bit figure is by the value of putting, perhaps at least one is by the value of putting in its 8 adjacent macro block positions, and then current macro need reduce mosquito noise.The reduction of mosquito noise realizes by reducing initial bit rate quantization scale code.
1-6 introduces specific embodiments of the invention below with reference to accompanying drawing.Those skilled in the art is easy to recognize that the following detailed description only is the purpose that is in explanation, and the present invention is not limited to these embodiment.
Be illustrated in figure 1 as the block diagram of video coding system 100 in accordance with a preferred embodiment of the present invention.Described video encoder 100 is the Parallel Digital processor preferably, BCM7040 single channel mpeg encoder or BCM7041 binary channels mpeg encoder as the production of Broadcom company, be to be real-time video compression and multiplexed the design, as be mpeg encoded or the like.Encoder 100 can synthesize on an independent chip, but and is installed on digital mobile video camera imprinting DVD, game machine, desktop multimedia equipment, video transmission equipment, video production system, video flowing and the equipment such as video conference device, safety monitoring system.By a kind of new video compression and coding techniques are provided, and propose a kind of new mosquito noise according to this technology and detect and coding method, the present invention has overcome the shortcoming of prior art.
Encoder 100 comprises video input processor 102, master controller 104, motion estimation process device 106, digital signal processor 108, storage control 110, bit-stream processor 112 and multiplexing processor 114.Encoder 100 preferably can be connected with video interface 120, external memory unit 122, packed data interface 124, host interface 126 and audio interface 128.Usually, video interface 120 provides digital video signal, and audio interface 128 provides digital audio and video signals.
Host interface 126 generally is connected with the external host (not shown), serves as the user interface between encoder 100 and the user.Host interface 126 will offer encoder 100 from the microcode of user or monitor system, order, data parameters etc.Described host interface 126 also will offer the user from the information that encoder 100 receives.Described host interface 126 provides the visit to packed data, and is used for providing unpressed digitized video and/or audio frequency and/or user data to encoder 100.
In a preferred embodiment of the invention, encoder 100 can run on programming mode or operator scheme, also can two kinds of pattern synchronization operations.Under programming mode, external host passes to master controller 104 by external host interface 126 with microcode, order and data parameters.Master controller 104 passes to microcode, order and data parameters video input processor 102, motion estimation process device 106, digital signal processor 108, storage control 110, bit-stream processor 112 and multiplexing processor 114 again.Under operator scheme, the motion video that video input processor 102 is caught from the external video source (not shown) by video interface 120.In another optional embodiment, video input processor 102 is caught motion video by host interface 126.
Then, video input processor 102 is carried out the vision signal statistical analyses, and the 3-2 that detects in the video content stops sequence and development (3-2 pulled up sequences and developments), as setting change, abrupt action, fade in/fade out etc.Thereby video input processor 102 can not only carry out resolution to the initial resolution frame to be dwindled and obtains compression, and can be to the frame (as SIF, half D1 etc.) that reduced resolution thus carry out resolution and dwindle and obtain compression.In addition, video input processor 102 can also carry out preliminary treatment to vision signal, as space filtering, noise removing, figure image intensifying etc.In addition, video input processor 102 can also reduce frame frequency by some frame of die-off (minimizing) (decimating (dropping)), realizes ratio control flexibly.Because described device 100 is worked in " feedforward " mode, can be used to carry out statistical analysis from the video feed of memory cell 122.Described feedback allows interframe (picture is to picture) analysis.
Video input processor 102 is assembled the vision signal of handling (scaled and processed) in proportion and is passed through storage control 110 and give memory cell 122 with the form of pulse train with data passes.Storage control 110 with above-mentioned signal storage in memory cell 122.In a preferred embodiment, encoder 100 is operated according to MPEG video/audio compression standard.Therefore, a data block is promptly represented a macro block, and this macro block is one 16 * 16 luminance pixel matrix and 2,4 or 88 * 8 colourity PEL (picture element) matrix according to the mpeg standard definition.For clarity sake, with reference frame or previous frame serve as with reference to relate to be encode, reconstruct and be stored in frame in the memory cell 112, this frame is compared with present frame.
Some part of storage control 110 retrieval present frame macro blocks and reference frame (being called search domain) in the memory cell 122 in this, and will it importing motion estimation process device 106.Motion estimation process device 106 compares present frame macro block and corresponding reference retrieval zone according to the condensed instruction sequence, thereby generates the motion estimation of present frame macro block.Described calculating is used to remove the time redundancy in the vision signal.
Motion estimation process device 106 passes to master controller 104 with the motion estimation result, and present frame macro block and corresponding reference frame macro block are passed to digital signal processor 108.
Digital signal processor 108 determines whether contain mosquito noise and then it is carried out encoding process in the macro block.About mosquito noise detect and coding in conjunction with the accompanying drawings 2-6 describe in detail.In addition, in order to remove the spatial redundancy in the vision signal, digital signal processor 108 also will be carried out other macro block of series and handle operation, as discrete cosine transform, macro block (mb) type selection, quantification treatment, ratio control etc.Digital signal processor 108 passes to bit-stream processor 112 with packed data, thereby and further handle condensed frame reconstructed reference frame, by storage control 110 reference frame of reconstruct is passed to memory cell 122 then, and then cover (overwriting) some existing reference frames.
Bit-stream processor 112 is encoded into the mpeg format of standard according to the known coded command sequence of prior art with compressed video data, sends coded video data stream to packed data interface 124 by multiplexing processor 114 then.It should be noted that packed data interface 124 can be connected with any data holding device, as memory cell, transmission line, computer bus etc.
According to one embodiment of present invention, digital video and/or user data that multiplexing processor 114 is caught from external video/data source (not shown) by host interface 126.According to another embodiment of the present invention, multiplexing processor 114 is caught digital audio by audio interface 128.
Multiplexing processor 114 multiplexed encoded videos, digitized video and/or customer traffic (being received from bit-stream processor 112) also generate the data flow of mpeg standard form, the flow filament that for example divides into groups (packetized elementary stream), program flow (program stream), transport stream (transport stream) or the like according to the multiplexed command sequence of optimizing.Multiplexing processor 114 spreads multi-channel video/audio/data passs packed data interface 124, also multi-channel video/audio/data is spread and passs host interface 126.
Described master controller 104 controls and scheduling video input processor 102, motion estimation process device 106, digital signal processor 108, storage control 110, bit-stream processor 112 and multiplexing processor 114.
Be structured flowchart as shown in Figure 2 according to mosquito noise detector in one embodiment of the invention coded system and damper part 200.The present invention has overcome the defective of prior art, proposes a kind of new video compression and coding method, and proposes a kind of new mosquito noise detection and reduction method according to this method.Thereby the present invention has improved the oeverall quality of video image.
Mosquito noise detector and damper 200 comprise that macroblock analysis device 204, position are provided with device/zero clearing device 205, framing bit figure analyzer 206 and mosquito noise damper 208.In a specific embodiment, each parts of mosquito noise detector and damper 200 can be realized in the digital signal processor 108 of encoder shown in Figure 1 100.But, those skilled in the art will recognize that the present invention is not limited to this plants configuration, the conceptual design that each parts in the system 200 can be different will principle according to the invention.
Mosquito noise detector and damper 200 receive as the multitude of video frame 202 of input and determine whether the macro block in the frame is high activity macro block.The present invention takes relativity of time domain, according to raster scan order with unidirectional (single pass) coding method calculating and coded macroblocks to detect mosquito noise.That is to say that from left to right, from top to bottom, delegation connects delegation ground and calculates described macro block.It is inner and on every side that mosquito noise mainly appears in the picture frame high activity areas.Described high activity areas is made of one group of neighboring macro-blocks, and the difference of each macro block all is higher than the threshold value that rule of thumb obtains.
After the high activity of macroblock analysis device 204 computing macro blocks, the position is provided with whether device/zero clearing device 205 these macro blocks of indication are high activity macro blocks.In one embodiment, if current macro is high activity macro block, the position is provided with the respective macroblock positional value in device/205 couples of framing bit figure of zero clearing device; If current macro is not high activity macro block (as a low activity macro block), then the position is provided with the respective macroblock position zero clearing in device/205 couples of framing bit figure of zero clearing device.206 couples of framing bit figure of framing bit figure analyzer analyze to determine whether contain mosquito noise in this frame then.If have quilt value of putting (being at least one in current macro position and eight macro block positions adjacent with the current macro position) in the framing bit figure in nine macro block positions at least, then current macro need reduce mosquito noise.The reduction of mosquito noise realizes by reducing initial bit rate quantization scale code.
Be to indicate according to an embodiment of the invention whether macro block is the flow chart of high activity macro block in the framing bit figure as shown in Figure 3.In the step 302, the present invention determines whether macro block is high activity macro block.If macro block is high activity macro block, the corresponding macro block position among the framing bit figure is by the value of putting, as step 304.If described macro block is not high activity macro block (a promptly low activity macro block), this macro block position among the framing bit figure is cleared, as step 306.
Be to determine according to an embodiment of the invention whether macro block is the flow chart of high activity macro block as shown in Figure 4.At first, step 402 is calculated the difference of each luminance block in the current macro; Then, step 404 is determined the minimum difference of luminance block; Step 406 compares the minimum difference and the mosquito noise threshold value of macro block brightness piece; Step 408 is calculated to determine that minimum difference is whether greater than (＞) or be less than or equal to (≤=) mosquito noise threshold value; In one embodiment, in the step 410, if described minimum difference greater than the mosquito noise threshold value, described macro block is considered to be high activity macro block; In the step 412, if described minimum difference is less than or equal to the mosquito noise threshold value, described macro block is considered to be low activity macro block.
Be the flow chart that calculates macro block position among the framing bit figure as shown in Figure 5.Step 502 is calculated current macro position and eight adjacent macro block positions thereof among the framing bit figure; Whether has the quilt value of putting at least in nine macro block positions in the step 504 judgment frame bitmap; In the step 506, if current macro position or at least one adjacent macroblocks position by the value of putting, then the current macro of current macro position representative need reduce mosquito noise; In the step 508, if neither one is by the value of putting in current macro position or the adjacent macroblocks position, then the current macro of current macro position representative need not reduce the mosquito noise processing.The frame encoding process is carried out according to the mode of raster scan, and delegation meets delegation, and a macro block connects a macro block.Thereby whether current macro the right and following adjacent macroblocks are that high activity macro block is unknown.In one embodiment, can utilize with the correlation of previous frame and estimate whether the macro block in the present frame belongs to high activity areas.
Fig. 6 a-6c is when the current macro that is applied in the given frame 602, the flow chart of one embodiment of the invention.Shown in Fig. 6 a, present frame 602 contains text (' TEXT '), and current macro 603 is closed on the text.Macro block 604 is parts of described text, is a high activity macro block, and macro block 606 is positioned at the text below, is low activity macro block.Shown in Fig. 6 b framing bit Figure 60 8 of frame 602.A macro block position among the corresponding framing bit Figure 60 8 of each macro block of frame 602.Fig. 6 b is in current macro position 610 shown in the framing bit figure.Shown in Fig. 6 c framing bit Figure 60 8 parts of current macro position 610 and adjacent with it 8 macro block positions 612,614 among the framing bit figure.Macro block position 612a among framing bit Figure 60 8 is by the value of putting, corresponding high activity macro block 604.Phase ortho position 612a to 612d is according to the former frame setting, and phase ortho position 614a to 614d is according to the present frame setting.Current macro position 610 is according to the present frame setting.Although current macro position 610 value of putting not among Fig. 6 c still needs to reduce mosquito noise by the current macro 603 of current macro position 610 representatives, because have quilt value of putting (612a that ascends the throne is by the value of putting) at least in eight positions adjacent with current macro position 610.Framing bit figure analyzer 206 shown in Figure 2 both can use the current macro position 610 from present frame, also can use the macro block position 610 (before covering) from former frame.Use macro block position in the preferred embodiments of the present invention from former frame.In this case, as known to persons skilled in the art, need operate, device/zero clearing device 205 and framing bit figure analyzer 206 are set to use position shown in Figure 2 simultaneously in the mode of streamline.
In a preferred embodiment, at first the minimum difference of the luminance block of current macro is got 2 to be the logarithm at the end, then it is compared with 10, thereby obtain mosquito noise threshold value of the present invention.Ten are based on threshold value after taking the logarithm, and (perhaps not using with 2 is 2 during as the logarithm at the end
10=1024).For a person skilled in the art, the present invention determines that the method for mosquito noise threshold value is not limited in said method, can also be by difference is directly relatively calculated the mosquito noise threshold value with 1024.
In one embodiment, by one again the difference value that repeatedly moves right until the logarithm value (Log2) that reaches zero mode calculated difference.The estimation result of Log2 is that difference value moves right to zero needed number of times.Can be according to the present invention since 1 or from 0 counting.Described difference value can move to right preceding or move to right after carry out verification, may produce different mosquito noise threshold values thus.
In a preferred embodiment, described mosquito noise threshold value approximately is 2
10=1024, in another embodiment, depend on that the calculating of being adopted is the method for the logarithm at the end with 2, the mosquito noise threshold value can be 2
9Or 2
11For a person skilled in the art, the present invention is not limited to any concrete mosquito noise threshold value, and this threshold value is adjustable to satisfy the demand of image and system.
In a preferred embodiment of the invention, the mosquito noise threshold value can rule of thumb be determined.By to utilizing specific mosquito noise threshold test to carry out mark, can rule of thumb determine the mosquito noise threshold value to the zone that frame contains mosquito noise.If detect and do not cover the zone that all contain mosquito noise, the mosquito noise threshold value can reduce.Covered the zone that does not have the mosquito noise phenomenon if detect, then the mosquito noise threshold value increases.The mosquito noise threshold value can be proofreaied and correct and finely tune by experience by using multiple video source with different qualities.
The reduction of mosquito noise realizes that by reducing initial bit rate quantization scale code the concrete reduction value of using depends on the bit rate that coding uses.For given bit rate, when more position is assigned to the mosquito noise zone (realizing by reducing this regional quantization scale), the present invention can compensate by the position distribution that reduces other zone.Distribute more position just to mean that better video quality is arranged, on the contrary the position of distributing video quality variation at least.Those skilled in the art knows, and the initial bit that depends on the initial code algorithm of choosing of concrete reduction value is distributed, and quantization scale code reduction value should depend on the requirement of encoder by the experience setting.For example, in one embodiment, the video bit rate is under the situation of 4Mbps, and described quantization scale code can be reduced to 4.
More than be that those skilled in the art knows in conjunction with certain embodiment description of this invention, can carry out various replacings to the present invention and not break away from protection scope of the present invention with the equivalence replacement.Any concrete environment that carries out according to content disclosed by the invention and the modification of material all do not break away from protection scope of the present invention.Therefore, scope of the present invention is not limited only to aforementioned disclosed specific embodiment, and all specific embodiments that fall in the claim protection range all belong to content of the present invention.
The application requires following priority: U.S. Provisional Application " mosquito noise detects and reduction (MosquitoNoise Detection and Reduction) ", the applying date is on May 26th, 2004, application number is 60/574,382, and the invention people is Itzik Yankilevich; And the applying date be on August 20th, 2004, application number is 10/922,084 U. S. application.More than application is all quoted by the application.
Claims (10)
1, a kind of video coding system comprises:
Input unit is used for receiving video signals, and described vision signal comprises a plurality of frames;
The mosquito noise detector is used to detect present frame and whether contains mosquito noise.
2, system according to claim 1, wherein, described video coding system also comprises the mosquito noise damper, reduces mosquito noise by reducing initial bit rate quantization scale.
3, system according to claim 1, wherein, described mosquito noise detector further comprises:
The macroblock analysis device is used for determining whether the current macro in the frame is high activity macro block;
Whether the position is provided with device/zero clearing device, is used for the position of marker frame bitmap current macro, be high activity macro block with the indication current macro.
4, system according to claim 3 wherein, further comprises the framing bit figure analyzer, is used to calculate framing bit figure and determines whether current macro needs to reduce mosquito noise.
5, a kind of system that detects mosquito noise in the video system, described system comprises:
The macroblock analysis device is used for by judging whether current macro is that high activity macro block determines whether the current macro in the picture frame contains mosquito noise;
The position is provided with device/zero clearing device, is used for whether the indication current macro is high activity macro block on framing bit figure.
6, system according to claim 5 wherein, further comprises the framing bit figure analyzer, is used for determining by calculating framing bit figure whether current macro needs to reduce mosquito noise.
7, a kind of system that detects and reduce mosquito noise in the video system, described system comprises:
The macroblock analysis device is used for by judging whether current macro is that high activity macro block determines whether the current macro in the frame contains mosquito noise;
The position is provided with device/zero clearing device, is used for whether the indication current macro is high activity macro block on framing bit figure;
The framing bit figure analyzer is used for determining by calculating framing bit figure whether current macro needs to reduce mosquito noise;
The mosquito noise damper is used for reducing mosquito noise by reducing initial bit rate quantization scale.
8, a kind ofly detect the method whether current macro in the vision signal contains mosquito noise, said method comprising the steps of:
Determine whether the current macro in the present frame is high activity macro block;
Whether the indication current macro is high activity macro block on framing bit figure.
9, method according to claim 8 wherein, further may further comprise the steps:
Determine by calculating framing bit figure whether current macro needs to reduce mosquito noise.
10, a kind ofly detect the method whether current macro in the vision signal contains mosquito noise, said method comprising the steps of:
By determining whether current macro is that high activity macro block determines whether the current macro in the present frame contains mosquito noise;
Whether the indication current macro is high activity macro block on framing bit figure;
Calculate framing bit figure to determine whether current macro needs to reduce mosquito noise;
Reduce mosquito noise in the present frame by reducing initial bit rate quantization scale.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US57438204P | 2004-05-26 | 2004-05-26 | |
| US60/574,382 | 2004-05-26 | ||
| US10/922,084 | 2004-08-20 |
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| CN100562108C CN100562108C (en) | 2009-11-18 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108174057A (en) * | 2018-01-10 | 2018-06-15 | 武汉烛照科技有限公司 | It is a kind of using video image interframe difference to the method and device of picture fast noise reduction |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108174057A (en) * | 2018-01-10 | 2018-06-15 | 武汉烛照科技有限公司 | It is a kind of using video image interframe difference to the method and device of picture fast noise reduction |
| CN108174057B (en) * | 2018-01-10 | 2020-06-23 | 武汉烛照科技有限公司 | Method and device for rapidly reducing noise of picture by utilizing video image inter-frame difference |
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