CN100420272C - A method and device to reduce image acquisition device noise - Google Patents
A method and device to reduce image acquisition device noise Download PDFInfo
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- CN100420272C CN100420272C CNB2006101458690A CN200610145869A CN100420272C CN 100420272 C CN100420272 C CN 100420272C CN B2006101458690 A CNB2006101458690 A CN B2006101458690A CN 200610145869 A CN200610145869 A CN 200610145869A CN 100420272 C CN100420272 C CN 100420272C
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Abstract
The disclosed method for reducing noise of image collector comprises: labeling register mark stored transient image fluctuation value as the appointed register group; checking whether the value in register group over threshold, yes to process the value in nearby non-appointed register and store result in the one with value over threshold. This invention can improve photo quality.
Description
Technical field
The present invention relates to the IMAQ field, relate in particular to a kind of method and apparatus that reduces image acquisition device noise.
Background technology
Image collecting device on the portable terminal is as mobile phone camera etc., because of its portability, by consumers in general are liked.Mobile phone camera adopts CCD (Charge Coupled Device usually, charge coupled device) or CMOS (Complementary Metal-Oxide Semiconductor, complementary metal oxide semiconductors (CMOS)) image sensing technology images acquired, under the different condition of brightness, camera can be discerned automatically, and change screening-mode to change the daylighting time, reach the purpose of adjusting the photograph light intensity.When extraneous light was more weak, the imager chip operating current was less, become the figure kine bias dark, at this moment will suitably increase the time for exposure carries out BLC; And when bright and clear or strong, suitably reduce the time for exposure, and prevent over-exposedly, image turns white.
Yet owing to reasons such as the performance difference of mobile phone camera and environment, when light intensity was more weak, camera noise was compared greatly with light intensity, had reduced the phase tablet quality.As shown in Figure 1, subject is A and two characters of D, and wherein, character A is near from light source 1, and character D is far away from light source 1, its imaging as shown in Figure 2, the picture of character A is clear, and the picture edge blurry of character D.
In the prior art, one of method that reduces image noise is by improve power supply treatment technology, grounding technology, design of drive circuit technology in imaging circuit, image quality is necessarily improved (with reference to " imaging circuit Research on anti-interference technique ", author: Wang Xuezhou, included " space flight is returned and remote sensing " the 25th the 1st phase of volume, in March, 2004).But this technology realizes reducing picture noise, improving image quality by increasing hardware circuit (chip internal and peripheral circuit), the manufacturing process complexity, and improvement cost is higher.
In addition,, also can reduce image noise, improve image quality by improving the manufacturing process of cmos image sensor.Cmos image sensor in the mobile phone application of fast development, will capture increasing market because of characteristics such as its volume is little, low in energy consumption, high integration.Up to now, the key technology of cmos image sensor is how to reduce dark current and improves signal to noise ratio.Dark current is meant the electric current of no rayed time sensing device under assigned voltage, and cmos image sensor is owing to having bigger Pixel Dimensions, so also can produce certain dark current in normal range (NR).By improving the CMOS manufacturing process, compressing the incidence that junction area can reduce dark current, also can shorten the binding time of dark current, thereby weaken the influence of dark current by improving frame rate.Noise mainly comprises shot noise, thermal noise, 1/f noise, non-homogeneous noise and still image noise, and its big young pathbreaker directly influences collection and the processing of cmos image sensor to signal.Take following measure can suppress noise and raising sensitivity in the CMOS manufacturing process: (1) adopts the unique circuit that reduces imbalance, uses the more stable transistor special process of manufacturing; (2) each pixel includes an amplifier relatively low to various changing sensitivities; (3) technology of preparing of reference ccd image sensor adopts correlating double sampling circuit technology and microlens array technology; (4) photodiode is designed to the aciculiform structure or buries the shape structure.The further developing of cmos semiconductor manufacturing technology in the future but this method of improving picture quality awaits.
Summary of the invention
The problem to be solved in the present invention provides a kind of method and apparatus that reduces image acquisition device noise, the defective of required cost height, complex process when improving the image quality of image collecting device to solve prior art.
The invention provides a kind of method that reduces image acquisition device noise, may further comprise the steps:
The register identification of each storage transition portion image fluctuation value is the appointment registers group;
Whether the numerical value that detects each register in the described appointment registers group exceeds threshold value, if exceed, then the numerical value that exceeds in the register register adjacent, non-described appointment registers group of threshold value with described numerical value is handled, and result is stored in the register that described numerical value exceeds threshold value.
Regularly detect or detect in real time the numerical value in each register in the described appointment registers group by setting-up time.
The numerical value that exceeds by gradient calculation, wavelet transformation or curve fit pair and described numerical value in the register register adjacent, non-described appointment registers group of threshold value is handled.
Described result is stored in described numerical value also to be comprised before exceeding the register of threshold value: described numerical value is exceeded the numerical value zero clearing in the register of threshold value.
The present invention also provides a kind of device that reduces image acquisition device noise, comprising: storage taxon, judgement comparing unit and data processing unit;
Described storage taxon is used for each register of the numerical value that collects of the described image collecting device of storage is classified, and the register identification of the numerical value that stable storage and luminous intensity is little is first group of register; The register identification of the numerical value that stable storage and luminous intensity is big is second group of register; With the register identification of storing the numerical value of fluctuation variation is the 3rd group of register;
Described judgement comparing unit is used for judging whether described the 3rd group of register has the numerical value of register to exceed threshold value;
Described data processing unit is used for gathering the numerical value that exceeds first, second adjacent group register of the 3rd group of register of threshold value with described numerical value, stores the 3rd group of register that described numerical value exceeds threshold value after the processing into.
Described processing comprises gradient calculation, wavelet transformation or curve fit.
Compared with prior art, the present invention has the following advantages:
The present invention judges the register that obtains storing noise by continuous variation of video image respective pixel either overt or covertly, and the data in this register are carried out smoothly waiting processing, obtain stable pixel, make the image immaculate fluctuating point after the processing, picture is smoothly soft, has satisfied user's vision requirement.
Description of drawings
Fig. 1 is the subject position view;
Fig. 2 is a subject imaging schematic diagram;
Fig. 3 is a kind of flow chart that reduces the image acquisition device noise method of embodiment one among the present invention;
Fig. 4 is a kind of structure chart that reduces the image acquisition device noise device of embodiment two among the present invention.
Embodiment
Embodiments of the invention one provide a kind of method that reduces image acquisition device noise, are example with the camera of mobile phone, as shown in Figure 3, may further comprise the steps:
Step s101 is to specify registers group with the register identification of transition portion image values between each storage subject and the background.Because noise contributions is constantly at random change of numerical value in the characteristic of pixel register, can cause LCD (Liquid Crystal Displayer, LCD) the video image respective pixel is continuous to change either overt or covertly.Therefore, the present invention is according to the situation of change of numerical value in the register in the special time before taking, all registers in the image collecting device are divided into two kinds: a kind of for being subjected to the little register of noise effect, another kind of for being subjected to the big register of noise effect, wherein be subjected to the little part of noise effect to comprise subject image and background parts image, being subjected to the big image section of noise effect is transition portion between above-mentioned subject image and the background parts image.
Step s102, whether the numerical value that detects each register in this appointment registers group in real time or regularly exceeds threshold value, and this threshold value is by can be according to the performance setting of camera own.For example, in camera is taken the some time, all registers are judged, exceeded threshold value, then change step s103 if its numerical value floats back and forth.At this moment, can identify this register, and the numerical value of this register is forced zero clearing, can certainly be set to any desired value.If do not exceed, then be left intact.
Step s103 handles the numerical value that exceeds in the register register adjacent, non-above-mentioned appointment registers group of threshold value with this numerical value.Wherein, processing method comprises signal processing methods such as gradient calculation, small echo processing, curve fit.Curve fit be exactly according to around numerical estimation in the register go out a suitable numerical value, subject image and background are seamlessly transitted.For example, the subject image light intensity is 10cd, and background is 4cd, then transition portion is modeled as 7cd.
Step s104 is stored in the register that this numerical value exceeds threshold value with result, obtains the pixel of monolithic stability.
Embodiments of the invention two also provide a kind of device that reduces image acquisition device noise, as shown in Figure 4, comprising: storage taxon 10, register cell 20, data processing unit 30, judgement comparing unit 40 and sensitization processor 50.Wherein storing taxon 10 is used for each register of register cell 20 memory image harvesters collection light intensity numerical value is carried out class indication: the stable and little numerical value of luminous intensity classifies as and is derived from background, is first group of register with the register identification of storing background parts numerical value; Stable and the big numerical value of luminous intensity classifies as subject, is second group of register with the register identification of storing subject part numerical value; The numerical value that fluctuation changes classifies as the light and shade transition relief part that is derived between object and the background, is the 3rd group of register with the register identification of storing transition portion numerical value; Above-mentioned first group of register, second group of register and the 3rd group of register pair are in different shooting conditions and shot object dynamic change; Judge comparing unit 40 is used for judging whether each register that is identified as the 3rd group of register has the numerical value of certain register to exceed threshold value, and will carry out mark above the register of threshold value; Data processor 30 is used for gathering with this and is labeled first group of adjacent register of register, the numerical value of second group of register, stores the above-mentioned numerical value that is labeled after handling into and exceeds in the register of threshold value; Sensitization processor 50 is used to survey light intensity, and dynamically adjusts numerical value in each register according to light intensity.
More than disclosed only be several specific embodiment of the present invention, still, the present invention is not limited thereto, any those skilled in the art can think variation all should fall into protection scope of the present invention.
Claims (6)
1. a method that reduces image acquisition device noise is characterized in that, may further comprise the steps:
The register identification of each storage transition portion image fluctuation value is the appointment registers group;
Whether the numerical value that detects each register in the described appointment registers group exceeds threshold value, if exceed, then the numerical value that exceeds in the register register adjacent, non-described appointment registers group of threshold value with described numerical value is handled, and result is stored in the register that described numerical value exceeds threshold value.
2. reduce the method for image acquisition device noise according to claim 1, it is characterized in that, regularly detect or detect in real time the numerical value in each register in the described appointment registers group by setting-up time.
3. reduce the method for image acquisition device noise according to claim 1, it is characterized in that the numerical value that exceeds by gradient calculation, wavelet transformation or curve fit pair and described numerical value in the register register adjacent, non-described appointment registers group of threshold value is handled.
4. reduce the method for image acquisition device noise according to claim 1, it is characterized in that, described result is stored in described numerical value also comprises before exceeding the register of threshold value: described numerical value is exceeded the numerical value zero clearing in the register of threshold value.
5. a device that reduces image acquisition device noise is characterized in that, comprising: storage taxon, judgement comparing unit and data processing unit;
Described storage taxon is used for each register of the numerical value that collects of the described image collecting device of storage is classified, and the register identification of the numerical value that stable storage and luminous intensity is little is first group of register; The register identification of the numerical value that stable storage and luminous intensity is big is second group of register; With the register identification of storing the numerical value of fluctuation variation is the 3rd group of register;
Described judgement comparing unit is used for judging whether described the 3rd group of register has the numerical value of register to exceed threshold value;
Described data processing unit is used for gathering the numerical value that exceeds first, second adjacent group register of the 3rd group of register of threshold value with described numerical value, stores the 3rd group of register that described numerical value exceeds threshold value after the processing into.
6. as the device of reduction image acquisition device noise as described in the claim 5, it is characterized in that described processing comprises gradient calculation, wavelet transformation or curve fit.
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| CNB2006101458690A CN100420272C (en) | 2006-11-21 | 2006-11-21 | A method and device to reduce image acquisition device noise |
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| CNB2006101458690A CN100420272C (en) | 2006-11-21 | 2006-11-21 | A method and device to reduce image acquisition device noise |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5214518A (en) * | 1989-12-22 | 1993-05-25 | Fuji Xerox Co., Ltd. | Multiple value image input equipment |
| JPH0775633A (en) * | 1993-06-30 | 1995-03-20 | Shimadzu Corp | Image processor |
| CN1600019A (en) * | 2001-12-03 | 2005-03-23 | 株式会社扶桑精造 | Digital data false alteration detection program and digital data false alteration detection apparatus |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5214518A (en) * | 1989-12-22 | 1993-05-25 | Fuji Xerox Co., Ltd. | Multiple value image input equipment |
| JPH0775633A (en) * | 1993-06-30 | 1995-03-20 | Shimadzu Corp | Image processor |
| CN1600019A (en) * | 2001-12-03 | 2005-03-23 | 株式会社扶桑精造 | Digital data false alteration detection program and digital data false alteration detection apparatus |
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