CN102572341A - Dynamic contrast automatic adjustment circuit and adjustment method thereof - Google Patents
Dynamic contrast automatic adjustment circuit and adjustment method thereof Download PDFInfo
- Publication number
- CN102572341A CN102572341A CN2010106178635A CN201010617863A CN102572341A CN 102572341 A CN102572341 A CN 102572341A CN 2010106178635 A CN2010106178635 A CN 2010106178635A CN 201010617863 A CN201010617863 A CN 201010617863A CN 102572341 A CN102572341 A CN 102572341A
- Authority
- CN
- China
- Prior art keywords
- point
- brightness
- dynamic
- mapping
- signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Landscapes
- Picture Signal Circuits (AREA)
- Television Receiver Circuits (AREA)
- Image Processing (AREA)
Abstract
The invention provides a dynamic contrast automatic adjustment circuit and an adjustment method thereof. Firstly, the number of points with brightness lower than a low threshold and the number of points with brightness higher than a high threshold in brightness input signals are calculated; secondly, all dynamic parameters such as mapping selection signals are calculated through a dynamic parameter calculating module according to calculating results and a linear mapping curve; thirdly, a dynamic brightness offset signal is increased in or decreased from the brightness input signals through a dynamic brightness adjustment circuit so that the brightness input signals are adjusted into brightness input signals to be mapped; and finally, the brightness input signals to be mapped is calculated point by point through a piecewise linear mapping module so as to obtain brightness signal output after mapping. The dynamic contrast automatic adjustment circuit and the adjustment method of the dynamic contrast automatic adjustment circuit enhance contrast of video images, and improve definition of image quality. Due to the fact that all adjustment in the dynamic contrast automatic adjustment circuit and the adjustment method of the dynamic contrast automatic adjustment circuit adopts a gradual change mode, and human eyes cannot feel flicker.
Description
Technical field
The present invention relates to a kind of contrast adjusting circuit and method of adjustment thereof, particularly relate to dynamic contrast automatic circuit and the method for adjustment thereof that to carry out the automatic dynamic adjustment to the contrast of image.
Background technology
People are increasingly high to the video quality requirement now, and the contrast of image becomes the important indicator of a lot of electronic video appliances.Existing technology; Though possessed function to video contrast's manual adjustment, but can exist the tonal gradation when video data to be distributed in when more secretly obtaining on the brighter gray scale, contrast not only can not promote; Can descend on the contrary, even the problem that gray scale merges occur.
Prior art adopts the method for GTG mapping curve to adjust according to video image degree of comparing more.The method that GTG is hinted obliquely at curve at first confirms to be used to carry out the curve of grey scale mapping according to the detection signal of the statistics with histogram data of image and scene; Then image is carried out grey scale mapping, thereby carry out the dynamic contrast adjustment.But there are some defectives in this method: when slight change appearred in the intensity profile in scene, the frequent switching appearred in scene detection between various patterns; Thereby make image flicker occur; And, the mode of this employing curve mapping, optional being limited in scope of not only dynamically adjusting; And because form itself needs storage, so expense is also bigger.
In sum, the dynamic contrast method of adjustment that can know prior art exists image flicker, problem that dynamically adjustment optional is limited in scope and expense is bigger, therefore, is necessary to propose improved technological means in fact, solves this problem.
Summary of the invention
For overcoming the above-mentioned shortcoming of prior art; Main purpose of the present invention is to provide a kind of dynamic contrast automatic circuit and method of adjustment thereof, and it not only can strengthen the contrast of video image, improves the definition of image quality; And make TV in playing process, float can not appear.
For reaching above-mentioned and other purpose, the present invention provides a kind of dynamic contrast automatic circuit, comprises at least:
The statistics with histogram module, it makes up brightness histogram according to the luminance input signal that receives, and adds up brightness in this brightness histogram less than the number of the point of low threshold and the brightness number greater than the point of high threshold;
The dynamic parameter computing module; According to each dynamic parameter of Linear Mapping curve calculation that this brightness provides greater than the number and the piecewise linear maps module of the point of high threshold less than the number of the point of low threshold, this brightness, this each dynamic parameter comprises that at least mapping selects the slope and the side-play amount of each section straight line in signal, this mapping curve;
Dynamic brightness adjustment circuit; Receive this each dynamic parameter and this luminance input signal, be used for this luminance input signal being increased greater than the number of the point of high threshold less than the number of the point of low threshold and this brightness or reducing by a dynamic brightness shifted signal to be adjusted into luminance input signal to be mapped according to this brightness; And
The piecewise linear maps module according to this each dynamic parameter that receives, should be calculated in luminance input signal pointwise to be mapped, with the luminance signal output after the acquisition mapping.
Further; This each dynamic parameter also comprises the greatest gradient parameter and the minimum slope parameter of number statistics low threshold, number statistics high threshold, this mapping curve, and the greatest gradient parameter and the minimum slope parameter of this number statistics low threshold, number statistics high threshold, this mapping curve produce through register configuration.
Further, this mapping selection signal is to confirm according to this number and this number greater than the point of high threshold less than the point of low threshold.
Further, if should less than the number of the point of low threshold with should be greater than the number of the point of high threshold all less than this number statistics low threshold, then mapping selects signal to put N1, selects corresponding mapping curve to strengthen the contrast of this luminance input signal mid portion; If should less than the number of the point of low threshold with should be greater than the number of the point of high threshold all greater than this number statistics high threshold, then mapping selects signal to be changed to N2, selects corresponding mapping curve to strengthen the contrast of these luminance input signal two end signals; Otherwise mapping selects signal to be changed to N3, selects corresponding mapping curve to make this luminance input signal to bright or dark direction adjustment, and wherein N1, N2, N3 are unequal.
Further, the slope of each section straight line and side-play amount select calculated signals to obtain according to this mapping in this mapping curve.
Further, in this mapping curve the slope precision of each section straight line at least greater than 4 bits
Further, this dynamic brightness shifted signal is according to obtaining with should calculating greater than the number of the point of high threshold less than the number of the point of low threshold.
For reaching above-mentioned and other purpose, the present invention also provides a kind of dynamic contrast automatic adjusting method, comprises the steps: at least
Obtain luminance input signal, make up the brightness histogram of an original image, and add up brightness in this brightness histogram less than the number of the point of low threshold and brightness number greater than the point of high threshold according to this luminance input signal;
Calculate each dynamic parameter less than the number of the point of low threshold, this brightness greater than the mapping curve that the number and the piecewise linear maps module of the point of high threshold provides according to this brightness, this each dynamic parameter comprises that at least mapping selects the slope and the side-play amount of each section straight line in signal, this mapping curve;
This luminance input signal is increased greater than the number of the point of high threshold less than the number of the point of low threshold and this brightness or reduce by a dynamic brightness shifted signal according to this brightness to be adjusted into luminance input signal to be mapped; And
According to this each dynamic parameter that receives, should luminance input signal pointwise to be mapped calculate, with the luminance signal output after the acquisition mapping.
Further; This each dynamic parameter also comprises the greatest gradient parameter and the minimum slope parameter of number statistics low threshold, number statistics high threshold, this mapping curve, and the greatest gradient parameter and the minimum slope parameter of this number statistics low threshold, number statistics high threshold, this mapping curve produce through register configuration.
Further, each dynamic parameter of this calculating also comprises the steps:
Relatively this number less than the point of low threshold, this number and this number statistics low threshold, this number greater than the point of high threshold are added up high threshold;
If should less than the number of the point of low threshold with should be greater than the number of the point of high threshold all less than this number statistics low threshold, then mapping selects signal to put N1, expression selects corresponding mapping curve to strengthen the contrast of this luminance input signal mid portion;
If should less than the number of the point of low threshold with should be greater than the number of the point of high threshold all greater than this number statistics high threshold, then mapping selects signal to be changed to N2, expression selects corresponding mapping curve to strengthen the contrast of these luminance input signal two end signals;
Otherwise mapping selects signal to be changed to N3, and expression selects corresponding mapping curve to make this luminance input signal to bright or dark direction adjustment, does not perhaps adjust;
Wherein N1, N2, N3 are unequal.
Further, the slope of each section straight line and side-play amount select calculated signals to obtain according to this mapping in this mapping curve.
Further, this dynamic brightness shifted signal is according to obtaining with should calculating greater than the number of the point of high threshold less than the number of the point of low threshold.
Further, this low threshold and this high threshold are produced by register configuration.
Compared with prior art, a kind of dynamic contrast automatic circuit of the present invention and method of adjustment thereof less than the number of the point of low threshold and the brightness number greater than the point of high threshold, and confirm that according to the result of statistics mapping selects signal through brightness in the statistics with histogram luminance input signal; So that when most signal distributions of luminance input signal during, strengthen the contrast of mid portion signal through broken line OABCD, when most signal distributions during at two ends in the centre; Strengthen the contrast of two end signals through broken line OA`B`C`D`, whole when dark partially when signal, what signal was suitable adjusts to bright direction; When signal integral body is bright partially; What signal was suitable adjusts to dark direction, through the present invention, has strengthened the contrast of video image; Improved the definition of image quality; And because all adjust the mode that all adopts gradual change among the present invention, human eye then can not experienced flicker
Description of drawings
Fig. 1 is the circuit structure diagram of a kind of dynamic contrast automatic circuit of the present invention;
Fig. 2 is the flow chart of steps of a kind of dynamic contrast automatic adjusting method of the present invention;
Fig. 3 is the dynamic contrast gain-adjusted state machine diagram of preferred embodiment of the present invention;
Fig. 4 is the sketch map of the dynamic brightness adjustment state machine of preferred embodiment of the present invention;
Fig. 5 is the Linear Mapping curve chart of the piecewise linear maps module of preferred embodiment of the present invention.
Embodiment
Below through specific instantiation and accompanying drawings execution mode of the present invention, those skilled in the art can understand other advantage of the present invention and effect easily by the content that this specification disclosed.The present invention also can implement or use through other different instantiation, and each item details in this specification also can be based on different viewpoints and application, carries out various modifications and change under the spirit of the present invention not deviating from.
Fig. 1 is the circuit structure diagram of a kind of dynamic contrast automatic circuit of the present invention, and Fig. 5 is the Linear Mapping curve chart of the piecewise linear maps module of preferred embodiment of the present invention.Please in the lump with reference to Fig. 1 and Fig. 5, a kind of dynamic contrast automatic circuit of the present invention circuit comprises statistics with histogram module 101, dynamic parameter computing module 102, dynamic brightness adjustment circuit 103 and piecewise linear maps module 104.
Wherein statistics with histogram module 101 is used for after obtaining the luminance input signal of original image, making up the brightness histogram of an original image, and in the statistics brightness histogram brightness less than the number dyn_cntl_reg of the point of low threshold and brightness number dyn_cnth_reg greater than the point of high threshold; Dynamic parameter computing module 102; Brightness according to obtaining is hinted obliquely at each dynamic parameter of Linear Mapping curve calculation that module 104 provides less than number dyn_cntl_reg, the brightness of the point of low threshold greater than the number dyn_cnth_reg and the piecewise linearity of the point of high threshold; Like number statistics low threshold cnt_low_thre; Number statistics high threshold cnt_high_thre; Signal line_sel is selected in mapping; Linear Mapping curve greatest gradient parameter gain_high_reg; Linear Mapping curve minimum slope parameter gain_low_reg, the Slope Parameters of each section straight line and offset parameter gain_OA, gain_AC, gain_CD, offset_OA, offset_AC and offset_CD in the Linear Mapping curve, wherein gain_OA, gain_AC, gain_CD are straight line OA, AC, CD (perhaps OA`; A`C`; C`D) slope, offset_OA, offset_AC, offset_CD are straight line OA, AC, CD (perhaps OA`, A`C`; C`D) side-play amount; Wherein number statistics low threshold cnt_low_thre, number statistics high threshold cnt_high_thre, greatest gradient parameter gain_high_reg and minimum slope parameter gain_low_reg produce through register configuration, and mapping selects the signal line_sel can be according to confirming that less than the number dyn_cntl_reg of the point of low threshold and greater than the number dyn_cnth_reg of the point of high threshold the slope of each section straight line and side-play amount gain_OA, gain_AC, gain_CD, offset_OA, offset_AC and offset_CD can calculate acquisition through the linearity curve that mapping selects signal line_sel to confirm in the Linear Mapping curve; Dynamic brightness adjustment circuit 103 is accepted luminance input signal, is used for before mapping, luminance input signal being adjusted toward the centre; To obtain luminance input signal ysrc to be mapped, specifically, whole dark partially like the luminance input signal of input; Then luminance input signal is added that a side-play amount remakes mapping; If luminance input signal is bright partially, then luminance input signal is deducted a side-play amount and remake mapping, in preferred embodiment of the present invention; The peaked absolute value bias_max of side-play amount is formed by register configuration, and maximum is no more than 16; Piecewise linear maps module 104 according to the dynamic parameter that receives, is calculated luminance input signal ysrc pointwise to be mapped, with the luminance signal output after the acquisition mapping.
Fig. 2 is the flow chart of steps of a kind of dynamic contrast automatic adjusting method of the present invention.As shown in Figure 2, a kind of dynamic contrast automatic adjusting method of the present invention comprises the steps:
Step 201: make up the brightness histogram of an original image according to luminance input signal, and in the statistics brightness histogram brightness less than the number dyn_cntl_reg of the point of low threshold and brightness number dyn_cnth_reg greater than the point of high threshold;
Step 202: according to the brightness that obtains less than the number dyn_cntl_reg of the point of low threshold, brightness number dyn_cnth_reg and each dynamic parameter of Linear Mapping curve calculation greater than the point of high threshold; Like number statistics low threshold cnt_low_thre; Number statistics high threshold cn_high_thre; Signal line_sel is selected in mapping; Linearity curve greatest gradient parameter gain_high_reg; Linearity curve minimum efficiency parameter gain_low_reg; The Slope Parameters of each section straight line and offset parameter gain_OA, gain_AC, gain_CD, offset_OA, offset_AC and offset_CD in the Linear Mapping curve; Wherein number statistics low threshold cnt_low_thre, number statistics high threshold cnt_high_thre, greatest gradient gain_high_reg and minimum slope gain_low_reg are produced by register configuration; Mapping selects the signal line_sel can be according to confirming that less than the number dyn_cntl_reg of the point of low threshold and greater than the number dyn_cnth_reg of the point of high threshold the slope of each section straight line and side-play amount gain_OA, gain_AC, gain_CD, offset_OA, offset_AC and offset_CD can calculate acquisition through the linearity curve that mapping selects signal line_sel to confirm in the Linear Mapping curve;
Step 203: luminance input signal is carried out the brightness adjustment; To obtain luminance input signal ysrc to be mapped; If promptly the luminance input signal of input is whole dark partially; Then luminance input signal is added that a side-play amount remakes mapping,, then luminance input signal is deducted a side-play amount and remake mapping if luminance input signal is bright partially; And
Step 204: according to the dynamic parameter that receives, luminance input signal ysrc pointwise to be mapped is calculated, with the luminance signal after the acquisition mapping.
Below will cooperate Fig. 1, Fig. 2 and Fig. 5 to further specify dynamic contrast automatic circuit of the present invention and its implementation through a concrete preferred embodiment.In preferred embodiment of the present invention, will describe with 10 bit accuracy, other precision can be by that analogy.
At first; Histogram is set up with statistical module 101 and is received luminance input signal; Make up the brightness histogram of original image according to luminance input signal, and in the statistics brightness histogram brightness less than the number dyn_cntl_reg of the point of low threshold and statistics brightness number dyn_cnth_reg (step 201) greater than the point of high threshold;
Secondly; Dynamic parameter calculation module 102 is calculated each dynamic parameter (step 202); Wherein number statistics low threshold cnt_low_thre, number statistics high threshold cnt_high_thre, greatest gradient parameter gain_high_reg and minimum slope parameter gain_low_reg produce through register configuration, below will specify and how calculate Slope Parameters and offset parameter gain_OA, gain_AC, gain_CD, offset_OA, offset AC and the offset_CD that each section straight line in signal line_sel and the Linear Mapping curve is selected in mapping.
Select signal line_sel for mapping, computational methods are following:
If less than the number dyn_cntl_reg of the point of low threshold and greater than the number dyn_cnth_reg of the point of high threshold all less than number statistics low threshold cnt_low_thre; Line_sel=1 then; Represent most signal distributions in the centre, mapping selects for use broken line OABCD to strengthen the contrast of mid portion signal;
If less than the number dyn_cntl_reg of the point of low threshold and greater than the number dyn_cnth_reg of the point of high threshold all greater than number statistics high threshold cnt_high_thre; Line_sel=2 then; Represent most signal distributions at two ends, mapping selects for use broken line OA`B`C`D to strengthen the contrast of two end signals;
Otherwise, line_sel=0 under other situation, straight line OBD is selected in expression mapping for use, and whole when dark partially when signal, signal is suitably to bright direction adjustment, and whole when bright partially when signal, what signal was suitable adjusts to dark direction, and signal does not adjust when suitable.
The slope of gain_AC representative mapping straight line AC section, in preferred embodiment of the present invention, it is example that gain_AC gets the 8bit precision, the gain_AC precision must be greater than 4bit otherwise flicker can be occurred.
Work as line_sel==0, the slope of straight line AC section equals 1, at this moment gain_AC==128;
Work as line_sel==1, the slope of straight line AC section is greater than 1, this moment 0＜gain_AC＜128;
Work as line_sel==2, the slope of straight line AC section is less than 1, this moment 128＜gain_AC＜255.
Fig. 3 is the dynamic contrast gain-adjusted state machine diagram of preferred embodiment of the present invention, below will cooperate Fig. 3 to specifically describe the computational methods of gainAC, gain_OA, gain_CD, offset_OA, offset_AC and offset_CD:
State GAIN_UDO: gainAC==128 under this state, directly get into the GAIN_UDO state behind the dynamic contrast automatic circuit electrification reset of the present invention, every field signal is judged the line_sel signal at first one time:
If line_sel==1 gets under the GAIN_UH state;
If line_sel==2 gets under the GAIN_UL state;
Other situation then continue to be retained under the GAIN_UDO state.
State GAIN_UL: after getting into this state, every field signal is judged the line_sel signal at first one time:
If line_sel is not equal to 2 and gain_AC==128, dynamic contrast automatic circuit of the present invention then redirect gets into the GAIN_UDO state, and this moment, gain_AC equaled 128;
If line_sel is not equal to 2 and gain_AC＜128, dynamic contrast automatic circuit then of the present invention continues to remain on the GAIN_UL state, and gain_AC equals original gain_AC and adds 1;
If line_sel equals 2 and gain_AC==gain_low_reg, dynamic contrast automatic circuit of the present invention then redirect gets into the GAIN_LOW state, and this moment, gain_AC equaled gain_low_reg;
If line_sel equals 2 and gain_AC＞gain_low_reg, dynamic contrast automatic circuit then of the present invention continues to remain on the GAIN_UL state, and gain_AC equaled original gain_AC and subtracted 1 this moment.
State GAIN_LOW: gain_AC==gain_low_reg under this state, every field signal judge the line_sel signal at first one time:
If line_sel equals 2, dynamic contrast automatic circuit then of the present invention continues to remain on the GAIN_LOW state; Otherwise get into the GAIN_UL state.
State GAIN_UH: after getting into this state, every field signal is judged the line_sel signal at first one time:
If line_sel is not equal to 1 and gain_AC==128, dynamic contrast automatic circuit redirect then of the present invention gets into the GAIN_UDO state, and this moment, gain_AC equaled 128;
If line_sel is not equal to 1, gain_AC＞128, dynamic contrast automatic circuit then of the present invention is retained in the GAIN_UH state, and gain_AC equaled original gain_AC and subtracted 1 this moment;
If line_sel equals 1 and gain_AC==gain_high_reg, dynamic contrast automatic circuit then of the present invention gets into the GAIN_HIGH state, and this moment, gain_AC equaled gain_high_reg;
If line_sel equals 1 and gain_AC＜gain_high_reg, dynamic contrast automatic circuit then of the present invention continues to remain on the GAIN_UH state, and gain_AC equaled original gain_AC and added 1 this moment.
State GAIN_HIGH: gain_AC==gain_high_reg under this state, every field signal judge the line_sel signal at first one time:
If line_sel equals 1, dynamic contrast automatic circuit then of the present invention continues to remain under the GAIN_HIGH state; Otherwise get into the GAIN_UH state.
OTHERS: directly jump to GAIN_UDO, at this moment gain_AC=128.
After obtaining straight line AC slope over 10 gain_AC, and know that the coordinate of AC mid point B is (512,512), then straight line AC can be formulated as follows:
(y-512)=gain_AC* (x-512)/128 (formula 1)
Offset_AC=512-gain_AC* (512/128) (formula 2)
Straight line OA is through initial point, so offset_OA=0 can be formulated as follows:
Y=gain_OA*x/128 (formula 3)
Because straight line OA and straight line AC intersect at the A point, getting A point abscissa is certain certain value 256, then formula 3 substitution formula 1 can be obtained gain_OA (slope of straight line OA).
Gain_OA=256-gain_AC (formula 4)
Because straight line CD is parallel to straight line OA, thus gain_CD=gain_OA, so straight line CD can be described below
Y=gain_CD*x/128+offset_CD (formula 5)
Because straight line CD hands over straight line AC in a C, and put C and put A about a B center symmetry, so the abscissa of some C gets 768, with formula 1, formula 4 substitution formula 5 can obtain
Offset_CD=1024-gain_OA* (1024/128) (formula 6)
Then, dynamic brightness adjustment circuit carries out the brightness adjustment to luminance input signal, to obtain luminance input signal ysrc to be mapped (step 203); Such as, if the luminance input signal of input is whole dark partially, then luminance input signal is added that a side-play amount remakes mapping; If luminance input signal is bright partially; Then luminance input signal is deducted a side-play amount and remake mapping, otherwise then brightness remains unchanged.The peaked absolute value bias_max of side-play amount forms through register configuration; Maximum is no more than 16; The side-play amount here is that dynamic brightness shifted signal dyn_offset is a signed number, is bias_max to the maximum, and minimum is-bias_max; Fig. 4 is the sketch map of the dynamic brightness adjustment state machine of preferred embodiment of the present invention; Below will cooperate Fig. 4 specifically to introduce the computational methods of dynamic brightness shifted signal dyn_offset, following simultaneously calculating can relate to following register: cntl_low (dynamically low-light level number low threshold), cntl_high (dynamically low-light level number high threshold); Cnth_low (dynamically high brightness number low threshold), cnth_high (dynamically high brightness number high threshold).
State ID LE: dynamic brightness shifted signal dyn_offset=0 under this state.Directly get into the IDLE state behind the general dynamic contrast automatic circuit electrification reset of the present invention, every field signal judges at first that once the number dyn_cntl_reg less than the point of low threshold reaches the number dyn_cnth_reg greater than the point of high threshold:
If dyn_cntl_reg＜cntl_low and dyn_cnth_reg＞cnth_high, the dynamic contrast automatic circuit entering LUM_SUB of team state then of the present invention;
If dyn_cnth_reg＜cnth_low and dyn_cntl_reg＞cntl_high then get into the LUM_ADD state;
Other situation then remain on the IDLE state, and are fine at IDLE STA representation signal, and the current dynamic contrast of need not doing is adjusted automatically.
State LUM_SUB: after getting into this state, every field signal is judged once less than the number dyn_cntl_reg of the point of low threshold and greater than the number dyn_cnth_reg of the point of high threshold at first:
If dyn_cntl_reg＜cntl_low and dyn_offset equal-bias_max, then get into the LUM_SUBM state, at this moment dyn_offset=-bias_max;
If dyn_cntl_reg＜cntl_low and dyn_offset＞-bias_max; Then remain under the LUM_SUBM state, dyn_offset equaled original dyn_offset and subtracted 1 this moment;
If dyn_cntl_reg is not less than cntl_low and dyn_offset equals 0, then get into the IDLE state, at this moment dyn_offset=0;
If dyn_cntl_reg is not less than cntl_low and dyn_offset less than 0, then continue to remain on the LUM_SUB state, dyn_offset equaled original dyn_offset and added 1 this moment;
Other situation then remain on the LUM_SUB state, and dyn_offset remains unchanged.
State LUM_SUBM: dyn_offset=-bias_max under this state, if dyn_cntl_reg＞cntl_low then gets into the LUM_SUB state; Other situation then remain under the LUM_SUBM state.
State LUM_ADD: after getting into this state, every field signal is judged once less than the number dyn_cntl_reg of the point of low threshold and greater than the number dyn_cnth_reg of the point of high threshold at first:
If dyn_cnth_reg＜cnth_low and dyn_offset equal bias_max, then get into the LUM_ADDM state, at this moment dyn_offset=bias_max;
If dyn_cnth_reg＜cnth_low and dyn_offset＜bias_max then remain under the LUM_ADD state, dyn_offset equaled original dyn_offset and added 1 this moment;
If dyn_cnth_reg is not less than cnth_low and dyn_offset equals 0, then get into the IDLE state, at this moment dyn_offset=0;
If dyn_cnth_reg is not less than cnth_low and dyn_offset greater than 0, then remain under the LUM_ADD state, dyn_offset equaled original dyn_offset and subtracted 1 this moment;
Other situation then remain on the LUM_ADD state, and dyn_offset remains unchanged.
State LUM_ADDM: dyn_offset=bias_max under this state, if dyn_cnth_reg＞cnth_low then gets into the LUM_ADD state; Other situation then remain under the LUM_ADDM state.
OTHERS: directly jump to the IDLE state, dyn_offset=0.
Calculate the luminance input signal ysrc to be mapped that sends into the linear mapping block 104 of segmentation at last,
Ysrc=yin+dyn_offset (formula 7)
Wherein yin is a luminance input signal.
At last, piecewise linear maps module 104 is calculated luminance input signal ysrc pointwise to be mapped according to the dynamic parameter that receives, and with the luminance signal (step 204) after the acquisition mapping, concrete computational methods are following:
If the abscissa 256 that ysrc is ordered less than A, then
ynew＝gainOA*ysrc；
If abscissa 256 that ysrc is ordered more than or equal to A and the abscissa 768 of ordering smaller or equal to C, then
ynew＝gainAC*ysrc+offfset_AC；
If the abscissa 768 that ysrc is ordered greater than C, then
ynew＝gainCD*ysrc+offset_CD。
Through foregoing circuit and method, it is thus clear that when the luminance input signal overwhelming majority of the present invention is distributed in the centre, can strengthen the contrast of mid portion signal through broken line OABCD; When most signal distributions during, can strengthen the contrast of two end signals through broken line OA`B`C`D` at two ends; When signal integral body was dark partially, what signal was suitable adjusted to bright direction; When signal integral body was bright partially, what signal was suitable adjusted to dark direction; Because all adjustment all adopt the mode of gradual change, human eye can not feel film flicker.
The foregoing description is illustrative principle of the present invention and effect thereof only, but not is used to limit the present invention.Any those skilled in the art all can be under spirit of the present invention and category, and the foregoing description is modified and changed.Therefore, rights protection scope of the present invention should be listed like claims.
Claims (13)
1. dynamic contrast automatic circuit comprises at least:
The statistics with histogram module, it makes up brightness histogram according to the luminance input signal that receives, and adds up brightness in this brightness histogram less than the number of the point of low threshold and the brightness number greater than the point of high threshold;
The dynamic parameter computing module; According to each dynamic parameter of Linear Mapping curve calculation that this brightness provides greater than the number and the piecewise linear maps module of the point of high threshold less than the number of the point of low threshold, this brightness, this each dynamic parameter comprises that at least mapping selects the slope and the side-play amount of each section straight line in signal, this mapping curve;
Dynamic brightness adjustment circuit; Receive this each dynamic parameter and this luminance input signal, be used for this luminance input signal being increased greater than the number of the point of high threshold less than the number of the point of low threshold and this brightness or reducing by a dynamic brightness shifted signal to be adjusted into luminance input signal to be mapped according to this brightness; And
The piecewise linear maps module according to this each dynamic parameter that receives, should be calculated in luminance input signal pointwise to be mapped, with the luminance signal output after the acquisition mapping.
2. dynamic contrast automatic circuit as claimed in claim 1; It is characterized in that: this each dynamic parameter also comprises the greatest gradient parameter and the minimum slope parameter of number statistics low threshold, number statistics high threshold, this mapping curve, and the greatest gradient parameter and the minimum slope parameter of this number statistics low threshold, number statistics high threshold, this mapping curve produce through register configuration.
3. dynamic contrast automatic circuit as claimed in claim 2 is characterized in that: it is to confirm according to this number and this number greater than the point of high threshold less than the point of low threshold that signal is selected in this mapping.
4. dynamic contrast automatic circuit as claimed in claim 3; It is characterized in that: if should less than the number of the point of low threshold with should be greater than the number of the point of high threshold all less than this number statistics low threshold; Then mapping selects signal to put N1, selects corresponding mapping curve to strengthen the contrast of this luminance input signal mid portion; If should less than the number of the point of low threshold with should be greater than the number of the point of high threshold all greater than this number statistics high threshold, then mapping selects signal to be changed to N2, selects corresponding mapping curve to strengthen the contrast of these luminance input signal two end signals; Otherwise mapping selects signal to be changed to N3, selects corresponding mapping curve to make this luminance input signal to bright or dark direction adjustment, and wherein N1, N2, N3 are unequal.
5. dynamic contrast automatic circuit as claimed in claim 4 is characterized in that: the slope of each section straight line and side-play amount select calculated signals to obtain according to this mapping in this mapping curve.
6. dynamic contrast automatic circuit as claimed in claim 5 is characterized in that: the slope precision of each section straight line is at least greater than 4 bits in this mapping curve.
7. dynamic contrast automatic circuit as claimed in claim 5 is characterized in that: this dynamic brightness shifted signal is according to obtaining with should calculating greater than the number of the point of high threshold less than the number of the point of low threshold.
8. a dynamic contrast automatic adjusting method comprises the steps: at least
Obtain luminance input signal, make up the brightness histogram of an original image, and add up brightness in this brightness histogram less than the number of the point of low threshold and brightness number greater than the point of high threshold according to this luminance input signal;
Calculate each dynamic parameter less than the number of the point of low threshold, this brightness greater than the mapping curve that the number and the piecewise linear maps module of the point of high threshold provides according to this brightness, this each dynamic parameter comprises that at least mapping selects the slope and the side-play amount of each section straight line in signal, this mapping curve;
This luminance input signal is increased greater than the number of the point of high threshold less than the number of the point of low threshold and this brightness or reduce by a dynamic brightness shifted signal according to this brightness to be adjusted into luminance input signal to be mapped; And
According to this each dynamic parameter that receives, should luminance input signal pointwise to be mapped calculate, with the luminance signal output after the acquisition mapping.
9. dynamic contrast automatic adjusting method as claimed in claim 8; It is characterized in that: this each dynamic parameter also comprises the greatest gradient parameter and the minimum slope parameter of number statistics low threshold, number statistics high threshold, this mapping curve, and the greatest gradient parameter and the minimum slope parameter of this number statistics low threshold, number statistics high threshold, this mapping curve produce through register configuration.
10. dynamic contrast automatic adjusting method as claimed in claim 9 is characterized in that, each dynamic parameter of this calculating also comprises the steps:
Relatively this number less than the point of low threshold, this number and this number statistics low threshold, this number greater than the point of high threshold are added up high threshold;
If should less than the number of the point of low threshold with should be greater than the number of the point of high threshold all less than this number statistics low threshold, then mapping selects signal to put N1, expression selects corresponding mapping curve to strengthen the contrast of this luminance input signal mid portion;
If should less than the number of the point of low threshold with should be greater than the number of the point of high threshold all greater than this number statistics high threshold, then mapping selects signal to be changed to N2, expression selects corresponding mapping curve to strengthen the contrast of these luminance input signal two end signals;
Otherwise mapping selects signal to be changed to N3, and expression selects corresponding mapping curve to make this luminance input signal to bright or dark direction adjustment, does not perhaps adjust;
Wherein N1, N2, N3 are unequal.
11. dynamic contrast automatic adjusting method as claimed in claim 10 is characterized in that: the slope of each section straight line and side-play amount select calculated signals to obtain according to this mapping in this mapping curve.
12. dynamic contrast automatic adjusting method as claimed in claim 11 is characterized in that: this dynamic brightness shifted signal is according to obtaining with should calculating greater than the number of the point of high threshold less than the number of the point of low threshold.
13. dynamic contrast automatic adjusting method as claimed in claim 8 is characterized in that: this low threshold and this high threshold are produced by register configuration.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010617863.5A CN102572341B (en) | 2010-12-30 | Automatic dynamic contrast control circuit and method of adjustment thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010617863.5A CN102572341B (en) | 2010-12-30 | Automatic dynamic contrast control circuit and method of adjustment thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102572341A true CN102572341A (en) | 2012-07-11 |
| CN102572341B CN102572341B (en) | 2016-12-14 |
Family
ID=
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103617792A (en) * | 2013-11-14 | 2014-03-05 | 天津三星电子有限公司 | Method for adjusting image display of display terminal and display terminal |
| CN112465729A (en) * | 2020-12-11 | 2021-03-09 | 四川长虹电器股份有限公司 | Method for dynamically adjusting image contrast based on television histogram |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5808697A (en) * | 1995-06-16 | 1998-09-15 | Mitsubishi Denki Kabushiki Kaisha | Video contrast enhancer |
| US20050100242A1 (en) * | 2001-07-06 | 2005-05-12 | Trifonov Mikhail I. | Automatic contrast enhancement |
| US20050213814A1 (en) * | 2004-03-23 | 2005-09-29 | Albert Lin | Method for adjusting image contrast |
| CN1925582A (en) * | 2005-08-24 | 2007-03-07 | 英特尔公司 | Techniques to improve contrast enhancement using a luminance histogram |
| CN101207754A (en) * | 2007-12-18 | 2008-06-25 | 上海广电集成电路有限公司 | Method for dynamical improving contrast based on video contents |
| CN101340511A (en) * | 2008-08-07 | 2009-01-07 | 中兴通讯股份有限公司 | Adaptive video image enhancing method based on lightness detection |
| CN201910868U (en) * | 2010-12-30 | 2011-07-27 | 无锡华润矽科微电子有限公司 | Automatic dynamic contrast control circuit |
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5808697A (en) * | 1995-06-16 | 1998-09-15 | Mitsubishi Denki Kabushiki Kaisha | Video contrast enhancer |
| US20050100242A1 (en) * | 2001-07-06 | 2005-05-12 | Trifonov Mikhail I. | Automatic contrast enhancement |
| US20050213814A1 (en) * | 2004-03-23 | 2005-09-29 | Albert Lin | Method for adjusting image contrast |
| CN1925582A (en) * | 2005-08-24 | 2007-03-07 | 英特尔公司 | Techniques to improve contrast enhancement using a luminance histogram |
| CN101207754A (en) * | 2007-12-18 | 2008-06-25 | 上海广电集成电路有限公司 | Method for dynamical improving contrast based on video contents |
| CN101340511A (en) * | 2008-08-07 | 2009-01-07 | 中兴通讯股份有限公司 | Adaptive video image enhancing method based on lightness detection |
| CN201910868U (en) * | 2010-12-30 | 2011-07-27 | 无锡华润矽科微电子有限公司 | Automatic dynamic contrast control circuit |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103617792A (en) * | 2013-11-14 | 2014-03-05 | 天津三星电子有限公司 | Method for adjusting image display of display terminal and display terminal |
| CN103617792B (en) * | 2013-11-14 | 2015-09-09 | 天津三星电子有限公司 | A kind of regulate display terminal picture to show method and display terminal |
| CN112465729A (en) * | 2020-12-11 | 2021-03-09 | 四川长虹电器股份有限公司 | Method for dynamically adjusting image contrast based on television histogram |
| CN112465729B (en) * | 2020-12-11 | 2022-07-08 | 四川长虹电器股份有限公司 | Method for dynamically adjusting image contrast based on television histogram |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101234958B1 (en) | Adaptive contrast enhancement | |
| KR100763239B1 (en) | Image processing apparatus and method for enhancing visibility of image on display | |
| CN104519281B (en) | The processing method and processing unit of a kind of image | |
| CN109983530A (en) | Ambient light adaptive display management | |
| JP4240032B2 (en) | Signal processing apparatus and method, recording medium, and program | |
| KR102490304B1 (en) | Display apparatus and recording media | |
| TW201506525A (en) | Method of controlling exposure time of high dynamic range image | |
| CN201910868U (en) | Automatic dynamic contrast control circuit | |
| TWI576817B (en) | Display with Automatic Image Optimizing function and Related Image Adjusting Method | |
| JP2018517993A (en) | Real-time video enhancement method, terminal, and non-transitory computer-readable storage medium | |
| KR20150002012A (en) | Histogram equalization apparatus using histogram compression | |
| TWI567707B (en) | Image adjusting method and related display | |
| KR20230003066A (en) | Dynamic range mapping method and apparatus | |
| US20230140259A1 (en) | Image dynamic range processing method and apparatus | |
| WO2023202173A1 (en) | Brightness adjustment method and apparatus, and computer device and computer-readable storage medium | |
| WO2023082859A1 (en) | Image processing method, image processor, electronic device, and storage medium | |
| US9571744B2 (en) | Video processing method and apparatus | |
| CN114119432A (en) | Image processing method, image processing device, electronic equipment and storage medium | |
| KR20060056304A (en) | Apparatus and method for adaptive image enhancement | |
| CN102572341A (en) | Dynamic contrast automatic adjustment circuit and adjustment method thereof | |
| CN102572341B (en) | Automatic dynamic contrast control circuit and method of adjustment thereof | |
| CN113808045A (en) | Image brightness adjusting method and device | |
| US11875487B2 (en) | High dynamic range image processing method and apparatus | |
| JP2012054659A (en) | Image processing apparatus, image processing method, and program | |
| US20240119573A1 (en) | Image processing apparatus, image processing method and computer-readable storage medium for direct memory accesses |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address |
Address after: 214135 -6, Linghu Avenue, Wuxi Taihu international science and Technology Park, Wuxi, Jiangsu, China, 180 Patentee after: China Resources micro integrated circuit (Wuxi) Co., Ltd Address before: 214061 Jiangsu city of Wuxi province Liangxi Road No. 14 Patentee before: WUXI CHINA RESOURCES SEMICO Co.,Ltd. |
|
| CP03 | Change of name, title or address |