CN100450153C - Flash detecting method and flash detecting device - Google Patents
Flash detecting method and flash detecting device Download PDFInfo
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- CN100450153C CN100450153C CNB200510022408XA CN200510022408A CN100450153C CN 100450153 C CN100450153 C CN 100450153C CN B200510022408X A CNB200510022408X A CN B200510022408XA CN 200510022408 A CN200510022408 A CN 200510022408A CN 100450153 C CN100450153 C CN 100450153C
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Abstract
The invention relates to a machine for testing the scintillation, including: a sampling device which is used for brightness-sampling about the pixels, a detecting device which is used for detecting the fluctuation-cycle of the brightness value in the vertical direction of the scanning, a judging device which is used to determine the existence of scintillations when the mentioned fluctuation-cycle within the preset frequency range, and the mentioned judging device contains a subtracting device which is used for subtracting the brightness values of two adjacent frames. One testing method: it sample selects the brightness of pixel, then it detects the fluctuation-cycle of the brightness value in the vertical direction of the scanning, then it determines the scintillations when the mentioned fluctuation-cycle within the preset frequency range, and the mentioned detecting step contains subtracting step. It can completely eliminates the impact of a video signals through the subtracting step about the brightness values of two adjacent frames.
Description
[technical field]
The present invention relates to a kind of flicker detection method and flicker detection equipment, the flicker that the brightness that is used to detect illumination light produces when using solid-state imaging unit pickup image under the situation of fixed frequency fluctuation.
[background technology]
In the process of IMAQ, particularly under the situation of brightness with the fixed frequency fluctuation of illumination light, the scan period of the illumination period of light source and photoelectric sensing imaging device, asynchronous can the generation glimmered.Be embodied in: light source phase point difference, make the intensity appearance difference in various degree of the interior IMAQ of the time interval of each scanning, therefore, flicker in various degree appears in the image of collection, cause the definition of image to be affected, and uneven situation appear in glossiness.Can suppress by of the flicker of certain countermeasure image, such as: integrated value regulated.In order to take this countermeasure, at first must detect the generation of flicker.
The equipment of conventional sense flicker comprises: integrating gear, carry out integration or average to every row, output row brightness value with the pixel level of the vision signal in effective scanning cycle in the frame; The static part draw-out device carries out addition or average corresponding to the capable brightness value of predetermined number of frames to every row, thereby output is from wherein having removed the capable brightness value of flicker component; Decision maker is carried out Fourier transform to the flicker component value of every row of static part draw-out device output, calculates the 50Hz of flicker component value or the frequency component of 60Hz and verifies, thereby judge the existence of flicker.The weak point of above technical scheme is: the circuit scale of carrying out the discrete Fourier transform processing is very big, and when throw light on light frequency and frame frequency have proportionate relationship, can not detect flicker.
At above deficiency, Chinese patent application number is 200310118414.6, open day is that the application case on September 1st, 2004 discloses a kind of flicker detection equipment, comprises integrating gear, be used for a frame of image or the pixel level integration of every row, to calculate capable brightness value; Draw-out device is used to extract the period of waves of capable brightness value on vertical scanning direction; And decision maker, be used for when period of waves is within a scheduled frequency range, judge to have flicker.Draw-out device calculates the difference that the fluctuation of row brightness value on vertical scanning direction causes to every row among a frame or, to a counting number continuously of same code in the difference, to calculate the count value as period of waves.Its weak point is: though adopted each row of vision signal is carried out integration or the average influence that obtains the row brightness value with the removal vision signal, but its effect is not the fine influence that only in fact can not remove video luminance signal with a frame signal fully, thereby the brightness variable signal of its sampling will distortion, sometimes in addition can serious distortion cause omit flicker, flase drop is surveyed or can't detect.And exist as noise signal, when influencing certain differential code (plus or minus), can influence the continuous number of the identical differential code that counter counts, finally influence the output result of decision maker.
[summary of the invention]
The present invention has overcome the deficiencies in the prior art, and a kind of flicker detection method and flicker detection equipment are provided, and eliminates the influence of vision signal, and reduces the influence of noise signal to the final decision result.
Technical scheme of the present invention is summarized as follows: a kind of flicker detection equipment, comprise sampling apparatus, and selected pixel is carried out luma samples; Draw-out device extracts the period of waves of brightness value on vertical scanning direction; Decision maker, when described period of waves is in scheduled frequency range, judge and have flicker, described draw-out device comprises substracting unit, this substracting unit subtracts each other the corresponding brightness value of adjacent two frames, described sampling apparatus carries out addition with the brightness value of the same delegation multiple row of the selected row of every frame video, described draw-out device comprises the selecting device at zero point, luminance difference after being used for subtracting each other from the corresponding brightness value of adjacent two frames is searched the first zero and the 3rd zero point, the first zero and the 3rd zero point correspondence the difference indication period of waves of line number, the described first zero and the 3rd zero point be all less than the threshold value at zero point, the first zero and the 3rd zero point pairing line number difference more than or equal to 2 times periodic quantity at zero point.
Described draw-out device comprises devision device, is used for subtracting each other the back luminance difference that obtains divided by a coefficient, and exports the selecting device at zero point to.
A kind of flicker detection method comprises following steps:
Sampling step: the brightness of the selected pixel of sampling; Extraction step: extract the period of waves of brightness value on vertical scanning direction; Determination step: when described period of waves is in scheduled frequency range, judge to have flicker; Described extraction step comprises subtraction step, described subtraction step is subtracted each other the corresponding brightness value of adjacent two frames, described sampling step is carried out addition with the brightness value of the same delegation multiple row of the selected row of every frame video, described extraction step comprises chooses step zero point, search the first zero and the 3rd zero point the luminance difference after the corresponding brightness value of adjacent two frames subtracts each other, the first zero and the 3rd zero point correspondence the difference indication period of waves of line number, the described first zero and the 3rd zero point be all less than the threshold value at zero point, the first zero and the 3rd zero point pairing line number difference more than or equal to 2 times periodic quantity at zero point.
Also comprise the step of being divided by before the described extraction step, the luminance difference that will subtract each other the back acquisition is divided by a coefficient.
Compared with prior art, effect of the present invention is: the present invention subtracts each other by each the row brightness value with adjacent two frame corresponding row, can eliminate the influence of vision signal fully.
The present invention adopts the method indication brightness fluctuation cycle choose zero point, and when choosing zero point, the first zero and the 3rd zero point correspondence the difference of line number more than or equal to 2 times periodic quantity at zero point.Avoid influencing choosing of zero point, make the flicker result of determination more accurate because there being noise signal.
By the present invention, can judge more accurately and whether deposit flicker, for follow-up whether carry out to proofread and correct an effective foundation is provided, thereby guarantee that image is stable more, level and smooth.
[description of drawings]
Fig. 1 is the block diagram of flicker detection equipment of the present invention.
Fig. 2 is the schematic diagram of selected row, particular column in the embodiment of the invention.
Fig. 3 be draw-out device of the present invention block diagram.
Fig. 4 is the luminance difference mean value sample distribution figure of the embodiment of the invention.
Fig. 5 is the flow chart of flicker detection method of the present invention.
[embodiment]
Also the present invention is described in further detail in conjunction with the accompanying drawings below by specific embodiment.As shown in Figure 1, a kind of flicker detection equipment comprises sampling apparatus 1, draw-out device 2 and decision maker 3.Vision signal input sample device 1 with effective scanning cycle of image-generating unit picked-up, sampling apparatus 1 is a unit with the picture frame, by using frame synchronizing signal and line synchronizing signal that pixel level is handled, the brightness value of the same delegation multiple row of the selected row of every frame video is carried out addition.Draw-out device 2 subtracts each other the corresponding brightness value of adjacent two frames, extracts the period of waves of brightness value on vertical scanning direction.Decision maker 3 compares brightness fluctuation cycle information and the predetermined value that draw-out device 2 extracts, and judges to have flicker when period of waves is in preset range.
Described selected line number can be the line number that a two field picture is comprised, in order to simplify processing, and can a preferred pairing number of scanning lines of power-supply fluctuation cycle.Described particular column can be listed as between the columns that a two field picture comprised one and fluctuate.But adjacent two frame select rows are identical with particular column.For example: sampling apparatus 1 can be chosen i and walk to j capable (i＜j) is select row, and k be listed as that (≤k≤m) is a particular column to the m row.As shown in Figure 2, be the image of 1600*1200 (the capable pixel of row pixel *) for a two field picture pixel, center that can image is an initial point, intercepts the image of a 512*296 (the capable pixel of row pixel *).
As shown in Figure 3, draw-out device 2 comprises storage device 21, is used to import the brightness from the pixel of the particular column of the selected row of sampling apparatus 1 output; Substracting unit 22 is used for the output of input sample device 1 and the output of storage device 21; Zero point, selecting device 23, were used to import the output of substracting unit 22; Counting device 24 is used to import selecting device 23 output at zero point.
The n frame of storage device 21 temporary transient store sample device 1 outputs, the 288th row are to the 1312nd row, and the 452nd walks to the brightness value A of the pixel of the 747th row
452, A
453, A
454... A
746, A
747Substracting unit 22 is listed as the 288th of sampling apparatus 2 outputs to the 1312nd row, and the 452nd walks to the brightness value B of the pixel of the 747th row
452, B
453, B
454... B
746, B
747Be listed as to the 1312nd row with the former frame the 288th of storage device 21 outputs, the 452nd walks to the brightness value A of the pixel of the 747th row
452, A
453, A
454... A
746, A
747Subtract each other, obtain the luminance difference C of adjacent two frames
452, C
453, C
454... C
746, C
747In order to simplify subsequent treatment, substracting unit 22 and zero point can increase a devision device between the selecting device 23.Devision device is imported the luminance difference C of adjacent two frames
452, C
453, C
454... C
746, C
747, and divided by a corresponding coefficient, export selecting device 23 at zero point to.Described coefficient is generally 2 n power (n 〉=1), preferably, can select 8 or 16 for use.
Zero point, selecting device 23 was searched the first zero and the 3rd zero point.As shown in Figure 4, the X coordinate is a line number among the figure, and the Y coordinate is adjacent two frame luminance difference.Zero point, selecting device 23 was with the luminance difference C of adjacent two frames
452, C
453, C
454... C
746, C
747Compare with threshold value at zero point (zerovalue) in order,, judge that this number is the first zero (zero1) when finding out first number less than threshold value at zero point (zerovalue), and the output control signal, enabling counting device 24 is counted.Whenever finish the comparison of a number, counting device 24 just increases a count value.Zero point, selecting device 23 continued to search second zero point (zero2) and the 3rd zero point (zero3).When searching second zero point (zero2) and the 3rd zero point (zero3), need satisfy this number less than threshold value at zero point (zerovalue), also need satisfy and be worth pairing line number difference more than or equal to the periodic quantity at zero point adjacent two zero points.Described zero point, periodic quantity was pre-stored in the selecting device 23 at zero point, was used to judge second zero point and the 3rd zero point.When zero point, selecting device 23 found the 3rd zero point (zero3), the output control signal stopped the counting of counting device 24.At this moment, counting device exports its numerical value of counting to decision maker 3.
The various situations that decision maker 3 prestores the supply frequency of illumination light and frame frequency correspondence are provided with the upper and lower bound of decision content, and when the count value of counting device output is in the scope of predetermined decision content, then judge to have flicker.
As shown in Figure 5, a kind of flicker detection method may further comprise the steps:
1) with the picture frame is unit,, pixel level handled that the brightness value of exporting the same delegation multiple row of the selected row of every frame video carries out addition by using frame synchronizing signal and line synchronizing signal.The columns of described particular column is at least 1, describedly chooses capable line number more than or equal to a pairing number of scanning lines of power-supply fluctuation cycle.
2) the corresponding brightness value of adjacent two frames is subtracted each other, obtain luminance difference and successively with zero point threshold ratio, when certain value less than zero point during threshold value, just find out the first zero.At this moment, the enabling counting device is counted.Whenever finish the comparison of a number, count value just adds 1, and continues to search second zero point (zero2) and the 3rd zero point (zero3).When finding the 3rd zero point (zero3), counting device stops counting.When searching second zero point (zero2) and the 3rd zero point (zero3), need satisfy this number less than threshold value at zero point (zerovalue), also need satisfy and be worth pairing line number difference more than or equal to the periodic quantity at zero point adjacent two zero points.
3) judge 24 count values of counting device whether in the scope of predetermined decision content, if this numerical value in the scope of predetermined decision content the time, is then judged to have flicker; Otherwise, just do not have flicker.
In step 2) in, to simplify the process, can will subtract each other the luminance difference of back acquisition divided by a coefficient.Described coefficient is generally 2 n power (n 〉=1), preferably, can select 8 or 16 for use.
Claims (4)
1. a flicker detection equipment comprises sampling apparatus, and selected pixel is carried out luma samples; Draw-out device extracts the period of waves of brightness value on vertical scanning direction; Decision maker when described period of waves is in scheduled frequency range, judges there is flicker that described draw-out device comprises substracting unit, and this substracting unit subtracts each other the corresponding brightness value of adjacent two frames; Described sampling apparatus carries out addition with the brightness value of the same delegation multiple row of the selected row of every frame video, described draw-out device comprises the selecting device at zero point, luminance difference after being used for subtracting each other from the corresponding brightness value of adjacent two frames is searched the first zero and the 3rd zero point, the first zero and the 3rd zero point correspondence the difference indication period of waves of line number, it is characterized in that: the first zero and the 3rd zero point be all less than the threshold value at zero point, the first zero and the 3rd zero point pairing line number difference more than or equal to 2 times periodic quantity at zero point.
2. flicker detection equipment according to claim 1 is characterized in that: described draw-out device comprises devision device, is used for subtracting each other the back luminance difference that obtains divided by a coefficient, and exports the selecting device at zero point to.
3. flicker detection method comprises following steps:
Sampling step: the brightness of the selected pixel of sampling; Extraction step: extract the period of waves of brightness value on vertical scanning direction; Determination step: when described period of waves is in scheduled frequency range, judge to have flicker; Described extraction step comprises subtraction step, and described subtraction step is subtracted each other the corresponding brightness value of adjacent two frames; Described sampling step is carried out addition with the brightness value of the same delegation multiple row of the selected row of every frame video; Described extraction step comprises chooses step zero point, search the first zero and the 3rd zero point the luminance difference after the corresponding brightness value of adjacent two frames subtracts each other, the first zero and the 3rd zero point correspondence the difference indication period of waves of line number, it is characterized in that: the described first zero and the 3rd zero point be all less than the threshold value at zero point, the first zero and the 3rd zero point pairing line number difference more than or equal to 2 times periodic quantity at zero point.
4. flicker detection method according to claim 3 is characterized in that: also comprise the step of being divided by before the described extraction step, the luminance difference that will subtract each other the back acquisition is divided by a coefficient.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101466014B (en) * | 2007-12-21 | 2011-05-11 | 瑞昱半导体股份有限公司 | Method for processing alternating image |
| JP5099701B2 (en) * | 2008-06-19 | 2012-12-19 | シャープ株式会社 | Signal processing device, signal processing method, control program, readable recording medium, solid-state imaging device, and electronic information device |
| US8077219B2 (en) * | 2009-02-12 | 2011-12-13 | Xilinx, Inc. | Integrated circuit having a circuit for and method of providing intensity correction for a video |
| CN101567977B (en) * | 2009-06-09 | 2013-09-18 | 北京中星微电子有限公司 | Flicker detection method and device thereof |
| CN102118549B (en) * | 2009-12-31 | 2013-02-27 | 敦南科技股份有限公司 | Image sensing device and method for sensing flashing frequency light by using same |
| US9363445B2 (en) * | 2014-06-30 | 2016-06-07 | Qualcomm Incorporated | Flash collision detection, compensation, and prevention |
| CN110213497B (en) * | 2019-05-15 | 2021-01-29 | 成都微光集电科技有限公司 | Method for detecting image flicker stripe and method for adjusting image exposure time |
| CN112513609B (en) * | 2019-05-28 | 2023-03-24 | 深圳大学 | Street lamp flicker effect analysis method and terminal |
| CN113552766B (en) * | 2020-04-07 | 2023-02-17 | 浙江宇视科技有限公司 | Flash-missing detection method and device for flash-explosion lamp, electronic equipment and storage medium |
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| CN1477862A (en) * | 2002-07-25 | 2004-02-25 | ��ʿͨ��ʽ���� | Solid-state image sensor |
| US20040201729A1 (en) * | 2001-10-02 | 2004-10-14 | Dwight Poplin | Automatic flicker frequency detection device and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20040201729A1 (en) * | 2001-10-02 | 2004-10-14 | Dwight Poplin | Automatic flicker frequency detection device and method |
| CN1477862A (en) * | 2002-07-25 | 2004-02-25 | ��ʿͨ��ʽ���� | Solid-state image sensor |
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Assignee: SHENZHEN BYD MICROELECTRONICS Co.,Ltd. Assignor: BYD Co.,Ltd. Contract record no.: 2011440020324 Denomination of invention: Flash detecting method and flash detecting device Granted publication date: 20090107 License type: Exclusive License Open date: 20070627 Record date: 20110901 |
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Address after: 518119 No.1 Yan'an Road, Kuiyong street, Dapeng New District, Shenzhen City, Guangdong Province Patentee after: BYD Semiconductor Co.,Ltd. Address before: 518119 No.1 Yan'an Road, Kuiyong street, Dapeng New District, Shenzhen City, Guangdong Province Patentee before: SHENZHEN BYD MICROELECTRONICS Co.,Ltd. Address after: 518119 No.1 Yan'an Road, Kuiyong street, Dapeng New District, Shenzhen City, Guangdong Province Patentee after: BYD Semiconductor Co.,Ltd. Address before: 518119 No.1 Yan'an Road, Kuiyong street, Dapeng New District, Shenzhen City, Guangdong Province Patentee before: BYD Semiconductor Co.,Ltd. |
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