CN1281067C - Automatic flash lamp device and automatic flash method for digital camera - Google Patents
Automatic flash lamp device and automatic flash method for digital camera Download PDFInfo
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- CN1281067C CN1281067C CN01134502.0A CN01134502A CN1281067C CN 1281067 C CN1281067 C CN 1281067C CN 01134502 A CN01134502 A CN 01134502A CN 1281067 C CN1281067 C CN 1281067C
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Abstract
The present invention relates to an automatic flash light device and an automatic flash method for a digital camera. A variable reference voltage signal is arranged on the basis of an arithmetic product of an analog gain value, a digital gain value and a Gamma value of the digital camera, and therefore, luminance brightness is sensed during flash generation for taking a picture, and the flash is stopped when a voltage signal representing the luminance brightness is larger than the variable reference voltage signal so as to obtain the identical exposure effect of a flash light under the condition of no matter what the gain setting is.
Description
Technical field
The invention belongs to a kind of flash unit and automatic flash of light method of digital camera, especially refer to a kind of can be according to flash unit and the automatic flash of light method of different gain settings with automatic adjustment luminous quantity.
Background technology
In the employed in-building type flash light techniques of known camera, the simplest is that execution mode is that photoflash lamp can only be luminous fully and not luminous fully (Full Or Nul1), and it is luminous excessively for fear of photoflash lamp, cause image bright excessively, as shown in Figure 1, can be outside flash lamp tube 11, add an optical detector 12 again, compare with a reference electrical signal Vref who presets by the brightness value that a comparator 13 comparison optical detectors 12 are responded to, can sense an amount of light time at this optical detector 12, the promptly disconnected power supply that removes flash lamp tube 11, and obtain suitable photoflash lamp light filling effect.
In order to control photoflash lamp more accurately, this default signal of telecommunication is variable, for example information such as aperture, subject distance is also included in and is considered, to calculate the default comparatively accurately signal of telecommunication.
Yet,, influence a setting that key factor is a yield value of image brilliance and quality with digital camera; Because the physical significance of gain is to amplify (or dwindling) semaphore from image sensor, so sense suitable light and when stopping fluorescent tube luminous, in theory, image sensor also should obtain suitable exposure when the optical detector of flash modules.But because the physical significance of gain is to be to amplify (or dwindling) semaphore from image sensor, because this signal of video signal is amplified by multiplier (-icator), the image that as a result in fact obtains was bright.Therefore, real the still having of aforementioned known flash unit gives improved necessity.
Summary of the invention
The object of the present invention is to provide a kind of automatic flash light device and automatic flash of light method of digital camera, it can be according to different gain settings with automatic adjustment luminous quantity, so that no matter be under the situation of which kind of gain setting, can both obtain identical exposure of flash lamp effect.
For achieving the above object, the automatic flash light device of the digital camera that the present invention proposes mainly comprises: an image sensor, in order to the image in the sensing external world; One image-processing circuit has an automatic exposure control circuit, an Automatic white balance circuit and a Gamma initialization circuit, can set analog-gain value, digital gain value and Gamma value respectively according to the image brilliance of this image sensor institute sensing; One flash modules, comprise a flash lamp tube, an optical detector and a comparator, this flash lamp tube is in order to provide the light source of getting phase time, the detected light brightness and be converted into a luminance voltage signal when this flash lamp tube is luminous of this optical detector, this comparator is this a luminance voltage signal and a variable reference voltage signal relatively, with when this luminance voltage signal during, stop the luminous of this flash lamp tube greater than this variable reference voltage signal; And a comparative voltage generator, produce this variable reference voltage signal values according to this analog-gain value, digital gain value and Gamma value.
Wherein the variable reference voltage signal values that produced of this comparative voltage generator is inversely proportional to the product of this analog-gain value, digital gain value and Gamma value.
Wherein this comparative voltage generator is multiplied by a reference voltage with the inverse of the product of this analog-gain value, digital gain value and Gamma value, with the value as this variable reference voltage signal.
A kind of automatic flash of light method of digital camera mainly comprises following step:
(A) provide a variable reference voltage signal, its value is inversely proportional to the product of analog-gain value, digital gain value and the Gamma value of digital camera;
(B) produce flash of light to take pictures; And
(C) sensor light brightness, the voltage signal of contemporary mass color brightness stop flash of light during greater than this variable reference voltage signal.
Wherein in step (A), the inverse of the product of the analog-gain value that this variable reference voltage signal values is a digital camera, digital gain value and Gamma value is multiplied by a reference voltage.
For further understanding structure of the present invention, feature and purpose thereof, do in detail with accompanying drawing and preferred embodiment.
Description of drawings
Fig. 1 is the schematic diagram of the flash unit of known camera.
Fig. 2 is the calcspar of the automatic flash light device of digital camera of the present invention.
Fig. 3 is the circuit diagram according to the comparative voltage generator of the automatic flash light device of digital camera of the present invention.
Embodiment
One preferred embodiment of the automatic flash light device of relevant digital camera of the present invention, please be earlier with reference to shown in Figure 2, it mainly includes an image sensor 21, one image-processing circuit 22, an one comparative voltage generator 23 and a flash modules 24, wherein, this image sensor 21 for example is the CCD device, can be in order to the image in the sensing external world, 24 of this flash modules comprise a flash lamp tube 241, one optical detector 242 and a comparator 243, this flash lamp tube 241 is in order to provide the light source of getting phase time, this optical detector 242 when this flash lamp tube 241 is luminous detected light brightness and will be converted to a brightness signal of telecommunication V, this comparator 243 is this signal of telecommunication and a reference voltage signal Vx relatively, with as this brightness signal of telecommunication V during, stop the luminous of this flash lamp tube 241 greater than this reference voltage signal Vx.
This image-processing circuit 22 is in order to provide the parameter setting of image capture, reaching the extraneous image that image sensor 21 is captured handles, it includes an automatic exposure control circuit 221, one Automatic white balance circuit 222 and a GAMA (Gamma) initialization circuit 223, in the middle of, this automatic exposure control circuit 221 can be set an analog-gain value according to the image brilliance of 21 sensings of this image sensor, this Automatic white balance circuit 222 can be set a digital gain value according to the image brilliance of 21 sensings of this image sensor, and this Gamma initialization circuit 223 then can be set a Gamma value according to the image brilliance of 21 sensings of this image sensor.
Aforesaid analog-gain value, digital gain value and Gamma value are in order to the multi-form gains such as analog gain, digital gain and Gamma adjustment of decision digital camera, wherein, so-called analog gain is the analog signal that is produced for image sensor 21, amplified afterwards through CDS (Corelated double sampling), therefore work as image sensor 21 and capture identical image, if the setting difference of analog gain, then the brightness of image is also inevitable different.So-called digital gain is for the digital signal by aforementioned amplification analog signal conversion gained, remakes different settings, and therefore, if the setting difference of digital gain, then the brightness of image is also inevitable different.And so-called Gamma adjustment is the brightness recast adjustment to each pixel of image, and therefore, if the setting difference of Gamma, then the brightness of image is also inevitable different.
Through as can be known from the above analysis, the analog gain of digital camera, digital gain and Gamma set the brightness that all can influence image, and in order to reach no matter under the situation of which kind of gain setting, can both obtain identical exposure of flash lamp effect, then must look the size of gain setting and dynamically adjust the fluorescent lifetime of flash lamp tube 241, with analog gain is example, if analog gain is g, the image brilliance that image sensor 21 is captured is y, and the Mathematical Modeling of then wanting to obtain identical exposure of flash lamp effect is g * y:k (constant)
And the image brilliance that image sensor 21 is captured can be by the optical detector 242 formed luminance voltage signal V representatives of flash modules 24, again because analog gain, digital gain and Gamma set all before flash lamp tube 241 is luminous all definite, therefore, analog yield value, digital yield value and the Gamma value that comparative voltage generator 23 just can set according to image-processing circuit 22 and dynamically set this reference voltage signal Vx, therefore, this reference voltage signal Vx can change according to analog yield value, digital yield value and Gamma value.Thus, when flash modules 24 luminous when taking pictures, the luminance voltage signal V that is produced by optical detector 242 sensitization just passes to comparator 243, and the reference voltage signal Vx that sets according to analog yield value, digital yield value and Gamma value in advance therewith compares, with when the V＞Vx, block the power supply supply of flash lamp tube 11, force luminous end, no matter thereby reach is under the situation of which kind of setting, all wants to obtain the purpose of identical exposure of flash lamp effect.
Aforementioned comparative voltage generator 23 is with analog yield value, digital yield value and Gamma value are via tabling look-up or calculating, and conversion produces this variable reference voltage signal Vx, its value system is inversely proportional to this analog-gain value, the product of digital gain value and Gamma value, it preferably is this analog-gain value, the inverse of the product of digital gain value and Gamma value is multiplied by a reference voltage Vref, Fig. 3 is the schematic diagram of a preferred embodiment of this comparative voltage generator 23, its circuit comprises the resistance R of four groups of serial connections, (comprise Vref with the partial pressure value that reference voltage Vref is provided, 3/4Vref, 1/2Vref and 1/4Vref), in addition with the conducting of four groups of switching transistor M3-M0 whether with these dividing potential drops Vref, 3/4Vref, 1/2Vref and 1/4Vref one as this variable reference voltage signal Vx, the switch controlling signal d3-d0 system of these four groups of switching transistor M3-M0 learns by tabling look-up, as shown in the figure, work as analog-gain value, the product value of digital gain value and Gamma value is 4,2,4/3,1 o'clock, d0, d1, d2 and d3 are respectively 1, and difference actuating switch transistor M0, M1, M2 and M3, making the variable reference voltage signal Vx that is produced according to this respectively is 1/4Vref, 1/2Vref, 3/4Vref and Vref.
Claims (4)
1. the automatic flash light device of a digital camera is characterized in that, comprising:
One image sensor is in order to the image of sensing one object;
One image-processing circuit has an automatic exposure control circuit, an Automatic white balance circuit and a gamma initialization circuit, can set analog-gain value, digital gain value and gamma value respectively according to the image brilliance of this image sensor institute sensing;
One flash modules, comprise a flash lamp tube, a photodetector and a comparator, the light source of this flash lamp tube when photographic images to be provided, this photodetector detects brightness and testing result is converted to a luminance voltage signal when this flash lamp tube is luminous, this comparator is this a luminance voltage signal and a variable reference voltage signal relatively, with when this luminance voltage signal during, stop the luminous of this flash lamp tube greater than this variable reference voltage signal; And
One comparative voltage generator, produce this variable reference voltage signal values according to this analog-gain value, digital gain value and gamma value, wherein, the variable reference voltage signal values that produced of this comparative voltage generator is inversely proportional to the product of this analog-gain value, numerical digit yield value and gamma value.
2. the automatic flash light device of digital camera as claimed in claim 1, it is characterized in that, wherein this comparative voltage generator is multiplied by a reference voltage with the inverse of the product of this analog-gain value, digital gain value and gamma value, with as this variable reference voltage signal values.
3. the automatic flash of light method of a digital camera is characterized in that, comprise an automatic exposure control circuit, an Automatic white balance circuit and a gamma circuit in this digital camera, and this method comprises following step:
(A) provide a variable reference voltage signal, its value is inversely proportional to the product of the gamma value of the digital gain value of analog-gain value, this Automatic white balance circuit of this automatic exposure control circuit and this gamma initialization circuit;
(B) produce flash of light to take pictures; And
(C) under the photoflash lamp luminance, carry out the brightness sensing, during greater than this variable reference voltage signal, stop flash of light with the voltage signal of contemporary mass color brightness.
4. the automatic flash of light method of digital camera as claimed in claim 3, it is characterized in that, wherein in step (A), the value of this variable reference voltage signal is that the inverse of product of analog-gain value, digital gain value and the gamma value of digital camera is multiplied by a reference voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN01134502.0A CN1281067C (en) | 2001-10-31 | 2001-10-31 | Automatic flash lamp device and automatic flash method for digital camera |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN01134502.0A CN1281067C (en) | 2001-10-31 | 2001-10-31 | Automatic flash lamp device and automatic flash method for digital camera |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1418017A CN1418017A (en) | 2003-05-14 |
| CN1281067C true CN1281067C (en) | 2006-10-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN01134502.0A Expired - Fee Related CN1281067C (en) | 2001-10-31 | 2001-10-31 | Automatic flash lamp device and automatic flash method for digital camera |
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| CN (1) | CN1281067C (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100381933C (en) * | 2003-12-04 | 2008-04-16 | 宇东电浆科技有限公司 | Flash lamp strength regulation system and method |
| CN100563306C (en) * | 2007-07-25 | 2009-11-25 | 北京中星微电子有限公司 | A kind of camera head light filling lamp autocontrol method and device |
| CN103220476B (en) * | 2012-01-20 | 2016-03-16 | 联咏科技股份有限公司 | Image processing apparatus and method |
| CN104135626A (en) * | 2014-07-31 | 2014-11-05 | 天津市亚安科技股份有限公司 | Device and method for automatically adjusting auxiliary lighting equipment |
| WO2016154926A1 (en) | 2015-03-31 | 2016-10-06 | 深圳市大疆创新科技有限公司 | Imaging device and light compensation control method and system therefor, and movable object |
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2001
- 2001-10-31 CN CN01134502.0A patent/CN1281067C/en not_active Expired - Fee Related
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