CN102023460B - Quick focusing method for digital camera - Google Patents
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Abstract
The invention discloses a quick focusing method for a digital camera, which is used for judging whether the digital camera needs to be focused again or not in an autofocusing phase. The quick focusing method comprises the following steps of: recording system time (defined as first time (T1)) after the camera is focused last time; capturing system time (defined as second time (T2)) before the camera is focused currently; when a difference value deltaT obtained by subtracting the first time T1 from the second time T2 is more than a threshold value of focusing time, running a fuzzy detection program to acquire a clear value; when the clear value is between a lower-limit focusing threshold value and an upper-limit focusing threshold value, setting a focusing focal length interval covering a reference focal length; capturing corresponding images in different focusing focal lengths respectively in the focusing focal length interval; calculating a reduced value of each image; and calculating a target focal length from the reduced value by a quadratic curve approximation method.
Description
Technical field
The invention discloses a kind of focusing method, being particularly to the decision when automatic focusing stage of a kind of digital camera needs the focus focusing method of focal length of adjustment.
Background technology
The user uses digital camera to take a photo, often is divided into several stages.First for opening digital camera, and this moment, digital camera promptly got into so-called capture preview phase (Live view).Second waits to take the photograph for the user aims at that thing is later half trips, in this simultaneously digital camera promptly get into automatic focusing stage.The 3rd pushes shutter entirely for the user, and this moment, digital camera then got into photographing phase (Shooting), and took corresponding image frame.
Automatically focusing stage refers to object is focused and do not pushed the focusing stage before taking as yet.Simple, be exactly digital camera course of action to the focusing of object when partly tripping.At this during one; It (is different lens location or step numbers that digital camera can move to the different focus position with camera lens; It is image sampling point (sampling steps)); And, decide clear picture or fog-level according in the definition values (Focus Value) that each lens location obtained.
Existing focusing calculation method has: universe search method (Global Search), mountain style search method (Hill-Climbing Search), and two search methods (Binary Search).Need consider needed time of search or the number of times of camera lens and the correctness of search at efficient method for searching.If expend too many search time, then can reduce the efficient of automatic focusing, and the number of times that camera lens moves too much can consume the digital cameral battery electric weight.Otherwise, then can influence the image quality of digital camera.
For instance, the universe search method is that the record camera lens whenever moves the digital picture that moves a step and obtained, and takes out the corresponding lens location of the digital picture with utmost sharpness afterwards again.Moving lens is accomplished focusing automatically to the position with utmost sharpness again.Please refer to the correlative value curve map of Fig. 1.
Though prior art can be found out the focusing focal length to object accurately.But digital camera when focusing each time, the digital camera action of still need once focusing again.So, focusing time and the power consumption for digital camera will influence to some extent.
Summary of the invention
In view of above problem; Fundamental purpose of the present invention is to provide a kind of rapid focus method of digital camera; Whether be suitable for digital camera and when automatic focusing stage, prejudge with the execution time of last time focusing too approachingly, the decision focal length of will focusing is adjusted to the target focal length again.
For reaching above-mentioned purpose, the rapid focus method of the disclosed digital camera of the present invention comprises: load last time to defocused system time, it is defined as the very first time (T1); Capture the preceding system time of this focusing, it is defined as second time (T2); The resulting difference (T2-T1) that deducts the very first time when second time is then blured trace routine, to obtain clear value greater than focusing time threshold value; When clear value at lower limit focusing threshold value with between the upper limit focusing threshold value time, then set one contain the benchmark focal length focusing focal length interval; From focusing focal length interval, capture corresponding contrast images at different focusing focal lengths respectively; Calculate the correlative value of each contrast images; From correlative value, choose maximal value, the focal length of the correlative value of being selected is set at the target focal length.
In above-mentioned fuzzy trace routine, may further comprise the steps in addition: in contrast images, set at least one resample area, resample area has a plurality of image pixels; The pixel value of all two adjacent image pixels in the resample area is distinctly compared, obtain a plurality of contrast differences; If the contrast difference then adds up clear value greater than preset threshold value; Repeat to calculate and the step that adds up clear value, till all images pixel in accomplishing resample area.
At last, judge whether needs adjustment focal length according to the clear value that is obtained.When clear value at lower limit focusing threshold value with between the upper limit focusing threshold value time, set the focusing focal length interval of containing the benchmark focal length; From focusing focal length interval, capture corresponding image at different focusing focal lengths respectively; Calculate the correlative value of each image; Utilize the quafric curve approximatioss from correlative value, to calculate the target focal length.
The present invention is each shooting time according to the digital picture of continuous two width of cloth, and judges through fuzzy trace routine whether the current digital picture that captures need focus again.If the focal length of the focal length of the object in the current digit image and the digital picture of the last width of cloth during less than threshold value, then need not find focusing end farthest from nearest focusing end.Can effectively reduce like this outside the power consumption of moving lens, also can reduce the time of contrast.
About characteristic of the present invention and real the work, cooperate diagram to make most preferred embodiment now and specify as follows.
Description of drawings
Fig. 1 is the correlative value curve map of prior art;
Fig. 2 is the operation workflow figure of a kind of rapid focus program of the present invention;
Fig. 3 is the configuration diagram of the digital camera that the present invention was suitable for;
Fig. 4 is the schematic flow sheet of first kind of fuzzy trace routine of the present invention;
Fig. 5 is a resample area synoptic diagram of the present invention;
Fig. 6 is the schematic flow sheet of second kind of fuzzy trace routine of the present invention;
Fig. 7 A is a synoptic diagram of choosing horizontal neighbor of the present invention;
Fig. 7 B is a synoptic diagram of choosing vertical adjacent pixels of the present invention;
Fig. 7 C is the synoptic diagram of the clear value of statistics of the present invention;
Fig. 8 is the schematic flow sheet of the third fuzzy trace routine of the present invention;
Fig. 9 A is the edge synoptic diagram of image object in the target image of the present invention;
Fig. 9 B is the edge synoptic diagram of image object in the target image of the present invention;
Fig. 9 C is that edge pixel of the present invention is chosen synoptic diagram;
Figure 10 is the schematic flow sheet of the 4th kind of fuzzy trace routine of the present invention;
Figure 11 is time sequences figure of the present invention.
Wherein, Reference numeral:
90 digital still cameras, 91 lens group
92 photosensory assemblies, 93 storage elements
94 timing units, 95 processing units
410 target images, 411 focusing frames
511 contrast pixels, 512 object pixels
710 edge images
Embodiment
Digital camera of the present invention is being focused (auto focusing) during the stage automatically, and the focusing focal length is adjusted to the target focal length to object fast.When the spacing value of the system time of system time and this focusing of focusing last time during less than the focusing threshold value, digital camera can further judge whether to readjust the eyeglass arrangement of lens group.Please refer to shown in Figure 2ly, be the operation workflow figure of a kind of rapid focus program of the present invention.May further comprise the steps in the rapid focus program:
Step 100: load the system time and the benchmark focal length of last time focusing, this system time is defined as the very first time (T1);
Step 200: capture the preceding system time of this focusing, it is defined as second time (T2);
Step 300: the resulting difference (T2-T1) that deducts the very first time when second time is then blured trace routine, to obtain clear value greater than focusing time threshold value;
Step 310: judge whether clear value falls between upper limit focusing threshold value and the lower limit focusing threshold value;
Step 400: when clear value during greater than upper limit focusing threshold value, then directly with the focal length of target image as the target focal length;
Step 500: when clear value was focused threshold value less than lower limit, the focal length interval of then will focusing was set at nearest focal length focal length extremely farthest; And
Step 610: focus between the threshold value at lower limit focusing threshold value and in the upper limit when clear value, it is interval then to set a focusing focal length of containing the benchmark focal length;
Step 620: and from focusing focal length interval, capture corresponding contrast images at different focusing focal lengths respectively;
Step 630: the correlative value of calculating each contrast images; And
Step 640: from correlative value, choose maximal value, the focal length of the correlative value of being selected is set at the target focal length.
According to following digital camera function mode of the present invention is done further explanation at this.Aforesaid digital camera can be but be not limited to digital camera shown in Figure 2.For being illustrated more clearly in the inventive method, please reference synchronization Fig. 2 and Fig. 3.Fig. 3 is the configuration diagram according to the digital camera that the present invention was suitable for.In digital camera 90, comprise lens group 91, photosensory assembly 92, storage element 93, timing unit 94 and processing unit 95 at least.
Have a CD-ROM drive motor (not illustrating) and multi-disc eyeglass (not illustrating) in the lens group 91, lens group 91 is in order to the focal length of adjustment to object.CD-ROM drive motor is in order to adjusting the phase mutual edge distance of each eyeglass, and then produces different focusing focal lengths.Photosensory assembly 92 is connected in lens group 91, and photosensory assembly 92 converts the image frame of current scene to the electric signal of digital picture.The picture signal with being received that photosensory assembly 92 can continue is sent to processing unit 95.Processing unit 95 is electrically connected at photosensory assembly 92 and storage element 93.Storage element 93 is in order to store digital image and rapid focus program.Timing unit 94 is in order to write down the writing time of the digital picture that is captured at every turn.Processing unit 95 is except carrying out the Flame Image Process digital picture, and processing unit 95 is also carried out the rapid focus program according to the digital picture of being obtained.When processing unit 95 is once focused in every completion, all can write down in current the focusing focal length and time to storage element 93.For clearly demonstrating the focusing information of different time, it is the very first time therefore with the preceding once focusing timing definition of record; This focusing time was second time.Focusing focal length in the very first time is recorded as the benchmark focal length, is defined as target image (corresponding step 100 ~ step 200) at captured image of second time.
The resulting difference (T2-T1) that deducts the very first time when second time is not then focused less than focusing time threshold value again.The resulting difference (T2-T1) that deducts the very first time when second time is greater than focusing time threshold value, and 95 of processing units begin digital picture is blured trace routine, to obtain clear value (corresponding step 300).Please refer to shown in Figure 4ly, it is the enforcement aspect synoptic diagram of first kind of fuzzy trace routine of the present invention.
Step 311: acquisition target image;
Step 312: in target image, set at least one resample area, in resample area, have a plurality of image pixels;
Step 313: the pixel value of all two adjacent image pixels in the resample area is compared respectively, obtain a plurality of contrast differences;
Step 314: if the contrast difference then adds up clear value greater than preset threshold value; And
Step 315: repeating step 313 and step 314, till all images pixel in accomplishing resample area.
Please refer to resample area synoptic diagram shown in Figure 5.In first kind of fuzzy trace routine, in target image 410, more define at least one resample area.Resample area can be but be not limited to the whole picture 410 of marking on a map of opening one's eyes wide, and also can be that focusing frame 411 or people's face of the fixed position of presetting detects people's face focusing frame 411 (corresponding step 311～step 312) that the back is produced.Wherein, in digital camera 90, can be provided with a plurality of focusing frames 411, the partial fixing position of position distribution in target image 410 of focusing frame 411.Focusing frame 411 is in order to provide the digital camera reference position that the scene that 90 pairs of desires are taken is focused.For instance, when focusing frame 411 when be middle section, then 90 pairs of digital cameras preferentially with the object of middle section as the foundation of focusing; If focusing frame 411 be left when zone, then 90 of digital cameras can be with the object in left zone as the foundation of focusing.
When digital camera 90 is set its focusing frame 411 and be the focusing frame 411 of central area, then digital camera 90 action (corresponding step 313) that can focus and contrast the object of focusing frame 411.In like manner, the focusing frame 411 of other regional location also provides identical effect.People's face focusing frame 411 is corresponding focusing frames 411 that human face region produced of being judged according to digital camera 90.If when occurring a plurality of people's faces focusing frame 411 simultaneously, then one implement in aspect people's face focusing frame 411 that hypothesis then gets the shortest focal length as the resample area of judging at of the present invention this.In other words can get distance exactly and focus frame 411 as aforesaid resample area near people's face of digital camera 90.
The pixel value of all two adjacent image pixels in the calculating resample area of meeting repetition in the first enforcement aspect is used corresponding each group of generation and is contrasted difference.After in the first enforcement aspect, being to calculate all contrast differences earlier, just then can add up the action (corresponding step 314 ~ step 315) of clear value.The present invention just judges whether to add up clear value after can also the accumulative total step of step 314 being made into to have calculated the contrast difference at every turn, and the operation workflow of the second enforcement aspect please refer to Fig. 6.
Second implements aspect may further comprise the steps:
Step 321: acquisition target image;
Step 322: in target image, set at least one resample area, have a plurality of image pixels in resample area;
Step 323: the pixel value of all two adjacent image pixels in the resample area is done comparison respectively, obtain a plurality of contrast differences; And
Step 324: accumulative total is clear value greater than the quantity of the contrast difference of preset threshold value.
Implement to select two adjacent image pixels to handle respectively in the calculating contrast difference process of aspect second.Please refer to shown in Fig. 7 A and Fig. 7 B, it is respectively the synoptic diagram of choosing horizontal neighbor and vertical adjacent pixels.At this image pixel of desiring to compare is defined as object pixel 512, another neighbor of selecting is defined as contrast pixel 511.The mode of choosing of contrast pixel 511 can be that the adjacent or vertical adjacent mode of level is chosen and the object pixel adjacent pixels.The selection mode of object pixel 512 can be chosen (corresponding step 322) in regular turn by putting in order of pixel in the resample area.
For instance; If is example (supposing that collection of pixels is pixel_array [m] [n] pel array) with a two-dimensional array with the collection of pixels in the resample area, then the mode of choosing of object pixel 512 by the lowest number position (meaning is pixel_array [0] [0]) of array one by one move to maximum numbered positions (meaning is pixel_array [0] [n-1]).After all pixels in accomplishing each row, move in time delegation, shown in the arrow among Fig. 7 A by current row again.511 of contrast pixels can be chosen from a time pixel (horizontal direction or vertical direction) of object pixel 512.Again object pixel of being selected 512 and contrast pixel 511 are subtracted each other, use the contrast difference that produces target 512.In regular turn the object pixel that selects other 512 from target image 410 again, and calculate corresponding contrast difference (corresponding step 323).
At last, add up number, and the number of being calculated is regarded as clear value (corresponding step 324) greater than the contrast difference of preset threshold value.If observe with statistical graph, be example with Fig. 7 C, be the contrast difference at the transverse axis of Fig. 7 C, the longitudinal axis is a quantity, then clear value is right-hand hatched example areas area of Fig. 7 C.
Fuzzy trace routine more can utilize following variation to carry out except aforesaid step.Please refer to shown in Figure 8ly, it is the third the enforcement aspect synoptic diagram of fuzzy trace routine of the present invention.The third fuzzy trace routine comprises the following steps:
Step 331: carry out the Image Edge-Detection program, find out a plurality of edge pixels of the image object of target image;
Step 332: from edge pixel, select continuous a plurality of selected pixel;
Step 333: the maximal value of getting in the difference value of pixel value of adjacent selected pixel is adjacent difference;
Step 334: the maximum difference of getting selected pixel is total difference;
Step 335: adjacent difference is obtained contrast ratio divided by total difference;
Step 336: repeating step 332 ~ step 335, till the calculating of the contrast ratio of accomplishing all edge pixels; And
Step 337: accumulative total is clear value greater than the quantity of those contrast ratios of preset threshold value.
This one implement in aspect with target image 410 via the Image Edge-Detection routine processes after, produce respective edges image 710 (corresponding step 331) immediately, have a plurality of edge pixels in the image 710 on the edge of.Described in the present invention rim detection is drilled and sent method can be Sobel edge detection method, Dijkstra ' s algorithm or Canny edge detection algorithm etc.Please refer to shown in Fig. 9 A, it is the edge synoptic diagram of image object in the target image.
Please cooperate with reference to shown in the figure 9B, again edge image 710 read its pixel value in regular turn with the preferential mode of row major/row, use producing corresponding gray-scale distribution curve.For instance; If when edge image 710 is regarded as a two-dimensional array (it is example that edge image 710 is regarded as pixel_array [m] [n] pel array); And read out pixel value (it is defined as selected pixel) with the mode of row major (row major) in regular turn by the first row beginning of edge image 710, meaning is pixel_array [0] [x], x={0; 1 ..., n-1}.And pixel value and the position that will select pixel are recorded in respectively in the gray-scale distribution curve.When completion read edge image 710 first the row in pixel value after, then export corresponding first the row the gray-scale distribution curve.And other row in other edge images 710 carries out reading of corresponding gray-scale distribution curve.Except that this, also can utilize the mode of row preferential (column major) to read gray-scale distribution curve (corresponding step 332 ~ step 333).
Change the section that surpasses a variation threshold value by selected pixels in the gray-scale distribution curve again, and be referred to as edge section.From edge section, choose a plurality of edge pixels.With Fig. 9 C is the example explanation, in Fig. 9 C, has A, B, C, four edge pixels of D (scope of in Fig. 9 C, selecting with the dotted line circle).Adjacent in twos edge pixel is chosen one by one, is the edge pixel set at this with each group contrast distribution value defined.Therefore can be divided into (A, B), (B, C), (C, D) three groups of edge pixels set, with one group of total collection of pixels (A, D).Each group edge pixel set should have difference value separately mutually, and total collection of pixels also has a total difference.From the set of three groups of edge pixels, choose difference the maximum again, and that selected difference is maximum one group removed last total difference, obtain contrast ratio.In this enforcement aspect, (X Y) cuts the X pixel value and gets its absolute value for the Y pixel value, and it is said to please refer to following formula 1:
Max ((A, B), (B, C), (C, D))/(D, A) (formula 1)
Explain orally with following example at this, suppose from edge section, to choose four pixel A=38, B=46, C=68, D=82.Edge pixel set be respectively (A, B), (B, C) with (C, D), wherein distinctly be (A, B)=8, (B, C)=22, (C, D)=14, total difference then be (A, D)=44.The maximal value of three groups of edge pixels set is 22, therefore adjacent difference be (B, C), so contrast ratio is 22/44=0.5.
If when only having two pixels in the section on the edge of, then do not calculate the difference value of this one edge section.Because can cause the contrast ratio of this one edge section to become 1 like this, make whether it can't this edge section of right judgement be the edge of image object.After accomplishing this one edge section, then continue the calculating of remaining edge section in the gray-scale distribution curve, and obtain remaining difference value.After obtaining difference value again, then whether the comparing difference value is greater than preset threshold value.Calculate all quantity greater than the difference value of preset threshold value, with the quantity after adding up be defined as clear value (corresponding step 333 ~ step 337).
After relative the 3rd enforcement aspect will add up all contrast ratios, just begin the clear value of accumulative total.The 4th enforcement aspect then is after calculating contrast ratio earlier, whether judges the contrast ratio that is produced again greater than preset threshold value, and repeats this step till the calculating of accomplishing all contrast ratios.Please refer to shown in Figure 10 its is the 4th kind of another operation workflow synoptic diagram of implementing aspect.
Step 341: carry out the Image Edge-Detection program, find out a plurality of edge pixels of the image object of target image;
Step 342: from edge pixel, select continuous a plurality of selected pixel;
Step 343: the maximal value of getting in the difference value of pixel value of adjacent selected pixel is adjacent difference;
Step 344: the maximum difference of getting selected pixel is total difference;
Step 345: more adjacent difference is obtained one group of contrast ratio divided by total difference;
Step 346: judge and whether to organize contrast ratio greater than preset threshold value;
Step 347: accumulative total is clear value greater than the quantity of those contrast ratios of preset threshold value; And
Step 348: repeating step 341 ~ 347, till the calculating of accomplishing all contrast ratios.
After accomplishing above-mentioned fuzzy program (meaning is a completing steps 300), processing unit 95 can contrast the relativeness of clear value, lower limit focusing threshold value and upper limit focusing threshold value.When clear value during greater than upper limit focusing threshold value, then directly with the focal length of target image as target focal length (corresponding step 400).When clear value was focused threshold value less than lower limit, the focal length interval of then will focusing was set at nearest focal length focal length (corresponding step 500) extremely farthest.When clear value drops on lower limit focusing threshold value with between the upper limit focusing threshold value time, processing unit 95 can set one contain the benchmark focal length focusing focal length interval (corresponding step 600 ~ step 610).In the present invention the benchmark focal length is set at the interval focal length farthest of focusing focal length.Can certainly the benchmark focal length be set at the interval nearest focal length of focusing focal length or the benchmark focal length is set in the focusing focal length interval.And from focusing focal length interval, capture different contrast images (corresponding step 620) at different focusing focal lengths respectively.
Below with acquisition three numbered images in focusing focal length section as explanation, those skilled in the art does not still take off protection of the present invention for the change of the quantity of acquisition digital picture.Digital camera 90 is when focusing to object, and digital camera 90 can be adjusted to the interval focal length farthest of focusing focal length at the interval nearest focal length of focusing focal length.Then, processing unit 95 can write down the correlative value (corresponding step 630) of the contrast images of each.
At last, utilize the quafric curve approximatioss from correlative value, to calculate the target focal length, and lens focus is adjusted this focal length.Thus, digital camera 90 does not need originally mobile between farthest focusing focal length and the nearest focusing focal length.Therefore moving of eyeglass in the lens group 91 be can effectively reduce, and then the focusing speed and the power consumption that reduces digital camera 90 of digital camera 90 improved.
Be explanation digital camera and running of the present invention further, also please refer to shown in Figure 11ly that it is time sequences figure of the present invention.Transverse axis at Figure 11 is the time interval of acquisition digital picture; The longitudinal axis of Figure 11 from top to bottom is the time point that the time point that is respectively the photographing information (for example: exposure value, f-number or light sensitivity etc.) of the time point that makes public, load image, the time point that carries out the calculating of clear value, decision move eyeglass.After processing unit 95 was calculating clear value, processing unit 95 can be according to the position (corresponding step 640) of the mobile eyeglass of institute's result calculated decision.
At last, accomplish above-mentioned rapid focus program after, focus between threshold value with lower limit except dropping on upper limit focusing threshold value in the said clear value of enforcement aspect of the present invention, for clear value corresponding handling procedure is also arranged when the different focusing threshold values.
If on behalf of present focal length, clear value during greater than upper limit focusing threshold value, be best suited for the focusing focal length of object, so digital camera 90 does not need to readjust the focusing focal length again.If when clear value is focused threshold value less than lower limit, then represent the focusing focal length of digital camera 90 not drop on the object.Therefore digital camera 90 needs the adjustment focusing focal length of accent, so digital camera 90 can move farthest focal length and obtain corresponding image in different focal length from nearest focal length.The image that obtains from each, find out distinct image, and determine that the focal length of this image is the target focal length.
The present invention is according to the shooting time and the focal length of the digital picture of the last width of cloth, and is used for judging through fuzzy trace routine whether the current digital picture that captures need focus again.If the focal length of the focal length of the object in the current digit image and the digital picture of the last width of cloth during less than threshold value, then need not find focusing end farthest from nearest focusing end.Can effectively reduce like this outside the power consumption of moving lens, also can reduce the time of contrast.
Claims (5)
1. the rapid focus method of a digital camera is used for a digital camera when focusing stage automatically, and the focal length of will focusing is adjusted to a target focal length, it is characterized in that, this focusing method comprises:
Loading deadline of last time focusing is a very first time (T1) and a benchmark focal length, and the focusing focal length in this very first time (T1) is recorded as this benchmark focal length;
Capturing the preceding system time of this focusing was one second time (T2);
The difference (Δ T=T2-T1) that deducts this very first time when this second time is then carried out a fuzzy trace routine, to obtain a clear value greater than a focusing time gate bank value; And
When this clear value drops on lower limit focusing threshold value and when a upper limit is focused between the threshold value, then carries out following step:
A focusing focal length interval of this benchmark focal length is contained in setting;
From this focusing focal length interval, capture a corresponding contrast image at different focusing focal lengths respectively; Calculate a correlative value of each this contrast images; And
From those correlative values, choose maximal value, the focal length of this correlative value of being selected is set at this target focal length;
The difference (Δ T=T2-T1) that deducts this very first time when this second time is less than this focusing time threshold value, then focusing again;
When this clear value greater than this upper limit focusing threshold value, directly with the focal length of a target image as this target focal length, this target image is at this second time (T2) captured image;
When this clear value less than this lower limit focusing threshold value, the focal length interval of should focusing is set at nearest focal length focal length extremely farthest.
2. the rapid focus method of digital camera as claimed in claim 1 is characterized in that, this fuzzy trace routine comprises:
Capture a target image;
In this target image, set at least one resample area, this resample area has a plurality of image pixels;
The pixel value of all these adjacent two image pixels in this resample area is distinctly compared, obtain a plurality of contrast differences;
If this contrast difference then adds up this clear value greater than a preset threshold value; And
Repeat compared pixels and the step that adds up this clear value, till all those image pixels in accomplishing this resample area.
3. the rapid focus method of digital camera as claimed in claim 1 is characterized in that, this fuzzy trace routine comprises:
Capture a target image;
In this target image, set at least one resample area, this resample area has a plurality of image pixels;
The pixel value of all these adjacent two image pixels in this resample area is distinctly done comparison, obtain a plurality of contrast differences; And
Accumulative total is this clear value greater than the quantity of those contrast differences of a preset threshold value.
4. the rapid focus method of digital camera as claimed in claim 1 is characterized in that, this fuzzy trace routine comprises:
Carry out an Image Edge-Detection program, find out a plurality of edge pixels of the image object of a target image;
Calculate a plurality of contrast ratios of those edge pixels successively; And
Accumulative total is this clear value greater than the quantity of those contrast ratios of a preset threshold value;
Wherein, this step of calculating a plurality of contrast ratios of those edge pixels successively comprises:
From those edge pixels, select continuous a plurality of selected pixel;
One maximal value of getting in the difference value of pixel value of those adjacent selected pixels is an adjacent difference;
The difference value of those selected pixels of accumulative total is a total difference;
Should adjacent difference obtain this contrast ratio divided by this total difference; And
Repeat above-mentioned four steps, up to the calculating of this contrast ratio of accomplishing all those edge pixels;
Wherein, this step of a plurality of edge pixels of finding out the image object of this target image comprises: the edge image to carrying out producing after this Image Edge-Detection program reads its pixel value in regular turn with the preferential mode of row/row, produces corresponding gray-scale distribution curve; Change the edge section that surpasses a variation threshold value by selected pixels in this gray-scale distribution curve; And from this edge section, choose a plurality of edge pixels.
5. the rapid focus method of digital camera as claimed in claim 1 is characterized in that, when selecting the step of this target focal length, writes down present system time simultaneously.
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| CN102033388B (en) * | 2009-09-29 | 2012-06-27 | 华晶科技股份有限公司 | Quick focusing method of digital camera |
| CN102595049B (en) * | 2012-03-16 | 2014-11-26 | 盛司潼 | Automatic focusing control system and method |
| JP6204644B2 (en) * | 2012-08-15 | 2017-09-27 | キヤノン株式会社 | Imaging apparatus and control method thereof |
| CN103220465A (en) * | 2013-03-21 | 2013-07-24 | 广东欧珀移动通信有限公司 | Method, device and mobile terminal for accurate positioning of facial image when mobile phone is used for photographing |
| CN105338240A (en) * | 2014-08-12 | 2016-02-17 | 希姆通信息技术（上海）有限公司 | Shooting device and focusing method, device and system |
| CN105812835B (en) * | 2014-12-31 | 2019-01-15 | 联想(北京)有限公司 | A kind of information processing method and electronic equipment |
| CN104980663B (en) * | 2015-08-10 | 2019-03-29 | 联想(北京)有限公司 | The control method and device of Image Acquisition rapid focus |
| CN106412437B (en) * | 2016-10-19 | 2019-04-12 | Oppo广东移动通信有限公司 | Focusing method, device and the terminal of terminal |
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| JP2000047094A (en) * | 1998-07-30 | 2000-02-18 | Kyocera Corp | Autofocus control method for digital camera |
| KR100831865B1 (en) * | 2007-07-13 | 2008-05-22 | 엘지이노텍 주식회사 | Method for auto-focusing in camera module |
| CN101227561A (en) * | 2007-01-16 | 2008-07-23 | 索尼株式会社 | Image pickup system, image pickup apparatus, and interchangeable lens |
| CN100437332C (en) * | 2002-09-12 | 2008-11-26 | 佳能株式会社 | Automatic focusing device and method, camera device |
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2009
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000047094A (en) * | 1998-07-30 | 2000-02-18 | Kyocera Corp | Autofocus control method for digital camera |
| CN100437332C (en) * | 2002-09-12 | 2008-11-26 | 佳能株式会社 | Automatic focusing device and method, camera device |
| CN101227561A (en) * | 2007-01-16 | 2008-07-23 | 索尼株式会社 | Image pickup system, image pickup apparatus, and interchangeable lens |
| KR100831865B1 (en) * | 2007-07-13 | 2008-05-22 | 엘지이노텍 주식회사 | Method for auto-focusing in camera module |
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