CN102721988B - Sunshine duration measuring method based on sky visible-light images - Google Patents
Sunshine duration measuring method based on sky visible-light images Download PDFInfo
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- CN102721988B CN102721988B CN201210199585.5A CN201210199585A CN102721988B CN 102721988 B CN102721988 B CN 102721988B CN 201210199585 A CN201210199585 A CN 201210199585A CN 102721988 B CN102721988 B CN 102721988B
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Abstract
The invention discloses a sunshine duration measuring method based on sky visible-light images. The sunshine duration measuring method includes acquiring a series of sky visible-light images by image acquisition equipment at preset intervals; searching high-brightness pixels in a preset area of each sky visible-light image and counting the quantity of the high-brightness pixels; judging whether sunshine is shot in each sky visible-light image or not; determining that the sunshine is shot in a certain sky visible-light image when the quantity of the high-brightness pixels of the sky visible-light image is larger than or equal to a high-brightness pixel quantity threshold, and determining that the sunshine is not shot in the certain sky visible-light image when the quantity of the high-brightness pixels of the sky visible-light image is smaller than the high-brightness pixel quantity threshold; and computing sunshine duration according to the time interval and the quantity of the sky visible-light images shot with the sunshine. The relevance among the sky visible-light images and the direct solar irradiation intensity is built by means of fitting analysis, and accordingly the novel method for detecting or measuring the direct solar irradiation intensity in an image processing and analyzing mode is provided. The method provides a novel selectable scheme for measuring the sunshine duration.
Description
Technical field
The present invention relates to aerological sounding field, relate in particular to a kind of sunshine time measuring method based on sky visible images.
Background technology
Solar radiation is the key factor that affects general circulation and climate change.Direct solar radiation is the important component part of total solar radiation.From observing or taking measurement of an angle, direct solar radiation generally includes radiation and the sun scattered radiation of very narrow annular sky (a ring day scattering) around on vertical sun surface (approximately 0.5 °, visual angle).To direct solar radiation intensity, the measurement of irradiance in other words has important value in aerological sounding, sun power utilization and other field relevant to solar radiation, and therefore direct solar radiation intensity is the routine monitoring data of meteorological department.
The direct measurement of direct solar radiation intensity at present, is to utilize direct solar radiation table.Direct solar radiation table is mainly made up of light-intaking tube, induction pieces and tracking means conventionally.In the time of work, light-intaking tube is aimed at the sun; Induction pieces absorbs direct solar radiation and converts thereof into measurable electric signal; Tracking means also can be followed the tracks of the movement of the sun for supporting light-intaking tube, thereby makes light-intaking tube accurately follow the tracks of and aim at the sun.
For such direct solar radiation table, the small tracing deviation of tracking means will produce larger system deviation.Like this, in order to eliminate the impact of system tracking error, require direct solar radiation table can in real time, quickly and reliably follow the tracks of the sun.This requires highly to tracking means, and operation and maintenance is also very complicated.
Observation and the measurement of number when an application of direct solar radiation table is counterglow.Be that solar radiation shows the most intuitively sunshine.Sunshine time refers to the time number of the sun in an actual irradiation in ground, and it is defined as direct solar radiation intensity and meets or exceeds 120W/m
2the summation of that time, taking hour as unit, gets a decimal.The regularity of distribution of sunshine time, has important practical significance for rational deployment agricultural production, the construction that plans a city, exploitation tourist resources, design solar power station etc.Because direct solar radiation table can obtain the direct solar radiation intensity in any appointment moment, therefore, it can directly be used for Timing measurement direct solar radiation intensity add up sunshine time.
During due to counterglow, the measurement of number does not need to obtain each moment direct solar radiation intensity accurately, only needs to judge whether direct solar radiation intensity meets or exceeds 120W/m
2this threshold value, therefore also has some not use the sunshine time observation program of direct solar radiation table in prior art.
Sunshine time observation instrument based on burning trace method mainly contains dark-tube sunshine recorder and focusing sunshine recorder.This is the observation instrument at sunshine that most domestic meteorological station uses at present.But the traffic observation of dark cartridge type and focusing sunshine recorder be unable to do without manual operation, as heliogramma needs manual manufacture, installation and replacing, sunshine time need to carry out artificial judgment etc. according to sunlight path (or burnt trace), and this makes the automaticity of the type instrument lower.
Sunshine time observation instrument based on actinometry method, except aforesaid beam radia off-balancesheet, also has bimetallic strip sunshine recorder etc.The bimetallic strip that bimetallic strip sunshine recorder adopts is mechanical deformation type element, is subject to the temperature effect impact of expanding and shrinking, and repeatability is poor, and long-time stability are difficult to ensure, causes the type sensor measurement precision not high.
In addition, the CSD type sun heliograph of Kipp & Zonen company of Holland utilizes three electronic light sensing devices to measure total solar irradiance and scattering irradiance, the difference of recycling solar global irradiance and scattering irradiance obtains the direct irradiance of the sun, and the direct irradiance of this sun can be used to statistics and calculates sunshine time.China Meterological Science Research Institute designed a kind of sunshine recorder that utilizes integrating sphere principle and calculated sunshine time.But due to some shortcomings separately, all fail to be used widely in business.
Summary of the invention
The object of the invention is to provides a kind of brand-new direct solar radiation strength measurement method with a kind of brand-new design, and provides a kind of direct solar radiation strength meter and a kind of sunshine time measuring method based on this direct solar radiation strength measurement method.
The application's basic conception come from present inventor find the sun in sky visible images and around the quantity of high luminance pixel can reflect the size of direct solar radiation intensity.Specifically, the applicant's inventor has analyzed at the direct solar radiation intensity data sequences of long period scope inter-sync observation and corresponding sky Detection Method in Optical Image Sequences.The inventor is surprised to find, the sun and around present obvious monotonically increasing relation between the quantity of the high luminance pixel in certain area and direct solar radiation intensity, and can obtain fitting function with the matching relation between reflection high luminance pixel quantity and direct solar radiation intensity by fitting algorithm in sky visible images.
According to one aspect of the present invention, a kind of direct solar radiation strength measurement method based on sky visible images is provided, comprising:
Image acquisition step: utilize image acquisition equipment to obtain the sky visible images of predetermined instant;
High luminance pixel counting step: search for the high luminance pixel in the presumptive area of described sky visible images, and the quantity of high luminance pixel is counted;
Radiation intensity is calculated step: the matching relation between quantity and the direct solar radiation intensity of the high luminance pixel based in presumptive area described in predetermined sky visible images, calculate the direct solar radiation intensity of described predetermined instant according to the quantity of described high luminance pixel.
Preferably, described presumptive area can be the sun and the region in preset range around thereof in described sky visible images.
Preferably, described presumptive area can be the border circular areas of the central point extension predetermined radii of the sun image from described sky visible images.
Preferably, described direct solar radiation strength measurement method can also comprise sun image central point determining step, the position for the central point of described sun image of determining described sky visible images in described sky visible images.
Preferably, in described sun image central point determining step, can be according to elevation angle and the position angle with respect to described image acquisition equipment at the described predetermined instant sun, the position of the central point that calculates described sun image in described sky visible images.
Preferably, described predetermined radii can be 1.1～3 times of radius of the sun image in described sky visible images, more preferably 1.2～2 times.
Preferably, described high luminance pixel can be more than or equal to for gray-scale value in described sky visible images the pixel of predetermined gray threshold.Preferably, described gray threshold is chosen between 200-255.
Preferably, described matching is closed and is
y=a*e
bx+c
Wherein, y is the quantity of the high luminance pixel in described presumptive area, and x is direct solar radiation intensity, a, and b, c is fitting coefficient.
Preferably, described direct solar radiation strength measurement method also comprises image acquisition equipment regulating step: regulate described image acquisition equipment, make, for the arbitrary direct solar radiation intensity that is less than maximum possible direct solar radiation intensity, in the presumptive area of the described sky visible images that described image acquisition equipment obtains, to comprise non-high luminance pixel.
Preferably, described image acquisition equipment can obtain equipment for full visual field sky visible images, for obtaining full visual field sky visible images.
According to another aspect of the present invention, a kind of direct solar radiation strength meter based on sky visible images is provided, comprising:
Full visual field sky image obtains equipment, for obtaining the full visual field sky visible images of predetermined instant;
Sun image central point computing module, the position for the central point of sun image that calculates described full visual field sky visible images in the sky visible images of the described full visual field;
High luminance pixel counting module is searched for the high luminance pixel that gray-scale value is more than or equal to predetermined gray threshold, and the quantity of high luminance pixel is counted within the scope of the predetermined radii in the center of circle for the central point taking described sun image;
Radiation intensity is calculated module, for the matching relation between the quantity based on predetermined high luminance pixel and direct solar radiation intensity, calculates the direct solar radiation intensity of described predetermined instant according to the quantity of described high luminance pixel.
According to another aspect of the present invention, a kind of sunshine time measuring method based on sky visible images is provided, comprising:
Image acquisition step: utilize image acquisition equipment with a series of sky visible images of predetermined time interval acquiring;
High luminance pixel counting step: for each sky visible images, search for the high luminance pixel in its presumptive area, and the quantity of high luminance pixel is counted;
Sunshine determining step: for each sky visible images, judge whether it indicates sunshine; Wherein, in the time that the quantity of the high luminance pixel of described sky visible images is more than or equal to a high luminance pixel amount threshold, indicate sunshine; In the time that the quantity of the high luminance pixel of described sky visible images is less than described high luminance pixel amount threshold, represent all the time according to;
Sunshine time calculation procedure: according to the size in the described time interval and indicate that the quantity of the sky visible images at sunshine calculates sunshine time.
Preferably, described sunshine time measuring method can also comprise high luminance pixel amount threshold determining step: the matching relation between quantity and the direct solar radiation intensity of the high luminance pixel based in presumptive area described in predetermined sky visible images, calculate corresponding high luminance pixel amount threshold according to a predetermined direct solar radiation intensity threshold.
Preferably, described presumptive area can be the sun and the region in preset range around thereof in described sky visible images.
Preferably, described presumptive area can be the border circular areas of the central point extension predetermined radii of the sun image from described sky visible images.
Preferably, described sunshine time measuring method can also comprise sun image central point determining step: for sky visible images described in each, and the position of the central point of definite described sun image wherein in described sky visible images.
Preferably, in described sun image central point determining step, for sky visible images described in each, can be according to elevation angle and the position angle with respect to described image acquisition equipment at the corresponding moment sun of this sky visible images, the position of the central point that calculates described sun image in this sky visible images.
Preferably, described predetermined radii is 1.1～3 times of radius of the sun image in described sky visible images, more preferably 1.2～2 times.
Preferably, described high luminance pixel is the pixel that in described sky visible images, gray-scale value is more than or equal to predetermined gray threshold.Preferably, described gray threshold is chosen between 200-255.
Preferably, described matching is closed and is
y=a*e
bx+c
Wherein, y is the quantity of the high luminance pixel in described presumptive area, and x is direct solar radiation intensity, a, and b, c is fitting coefficient.
Preferably, described image acquisition equipment can obtain equipment for full visual field sky visible images, for obtaining full visual field sky visible images.
Technical scheme of the present invention has following beneficial effect:
(1) the present invention between visible images and direct solar radiation intensity, set up on high by Fitting Analysis associated, thereby provide a kind of mode of processing and analyzing by image of novelty to survey or measure the method for direct solar radiation intensity.This measurement for direct solar radiation intensity provides a kind of new possibility;
(2) in a kind of preferred implementation of the present invention, by utilizing the sky visible images in the full visual field, can avoid using complicated solar tracking device, also avoid the systematic measurement error being brought by tracking error simultaneously;
(3) measuring method of direct solar radiation intensity of the present invention can be applied in the various fields relevant to direct solar radiation ionization meter, as the measurement of sunshine time without barrier;
(4) because measuring method and the sunshine time measuring method of direct solar radiation intensity of the present invention are mainly that the mode of being processed and being analyzed by image is carried out, be therefore very suitable for automatically processing by computing machine, can greatly increase work efficiency.
Brief description of the drawings
Fig. 1 (a) shows the different full visual field sky visible images of two width with Fig. 1 (b);
Fig. 2 is the calculating schematic diagram of sun image center position in the sky visible images of the full visual field;
Fig. 3 is according to the process flow diagram of the direct solar radiation strength measurement method based on sky visible images of the present invention;
Fig. 4 is an embodiment according to direct solar radiation strength meter of the present invention;
Fig. 5 is according to the process flow diagram of the sunshine time measuring method based on sky visible images of the present invention.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in more detail.
In basic conception of the present invention, core is the sun and the matching relation between the quantity of high luminance pixel and the direct radiation intensity of the sun around thereof in sky visible images, therefore, below describe first respectively image acquisition step, high luminance pixel counting step and matching step in detail.
image acquisition step
Image acquisition step is to utilize image acquisition equipment to obtain the sky visible images of predetermined instant.In this sky visible images, include the image of desirable presumptive area.Conventionally, the image of this presumptive area refers to the sun and the image in preset range around thereof.
In one embodiment, this image acquisition equipment can obtain equipment for full visual field sky visible images, and as existing various total sky imagers in prior art or full visual field recording geometry, it can obtain the full view visible light image of whole sky substantially.The sky visible images obtaining is like this called full visual field sky visible images.Fig. 1 (a) shows respectively the different full visual field sky visible images of two width with Fig. 1 (b), wherein, in Fig. 1 (a), because cloud layer blocks or other reason, sun image crested; And can obviously see sun image in Fig. 1 (b).
In other embodiments, this image acquisition equipment can be that the local sky visible images of Limited eyeshot obtains equipment, as long as include needed presumptive area in this part sky visible images.The sky visible images obtaining is like this called local sky visible images.Obtain equipment for local sky visible images, it preferably has sun tracker, to follow the tracks of the operation of the sun, thereby can in officely mean all to include in local sky visible images that timing carves the image of needed presumptive area.
Obtain equipment than local sky visible images, full visual field sky visible images obtains equipment and can avoid using complicated sun tracker, and further avoids the systematic measurement error bringing due to tracking error.
high luminance pixel counting step
High luminance pixel counting step is the high luminance pixel of wanting in the presumptive area of search the sky visible images, and the quantity of high luminance pixel is counted.For this reason, first need to determine needed presumptive area.As previously mentioned, this presumptive area is the sun and the region in preset range around thereof normally, makes the image of this presumptive area mainly reflect direct radiation and the ring day scattering on sun surface, to can exclude the interference bringing due to reasons such as cloud layer scatterings.
Although this presumptive area can manually be set in the time sky visible images being carried out to image processing on image, for the ease of robotization processing, this presumptive area can be preferably that benchmark is set with the central point of the sun image that can calculate.The central point of the sun image on high position in visible images can and utilize various known parameters to calculate according to different image acquisition equipments.For example, in the time utilizing full visual field sky visible images to obtain equipment to obtain sky visible images, this full visual field sky visible images obtains equipment and conventionally adopts fish eye lens, and the position of the central point of sun image can calculate according to mode shown in Fig. 2.
As shown in Figure 2, the fish eye lens that full visual field sky visible images obtains in equipment is to take towards zenith direction, and the orientation in fish eye images is upper north (N), lower south (S), left east (E), right west (W).O point is that sky withstands on the subpoint in fish eye images, is also the central point of fish eye images, and OD is the imaging radius of fish eye images, and T is the position of the sun in celestial sphere, and P is the imaging point of the sun in fish eye images, the namely central point of sun image.H is sun altitude, and span is 0 ° ~ 90 °.A is the position angle of the sun, and span is-180 ° ~+180 °, and position angle is taking Due South to as zero, by south east northwards for negative, by south orientation west northwards for just.Wherein, elevation angle H and position angle A can utilize the residing longitude of image acquisition equipment, latitude and image imaging Time Calculation to obtain.
At sunrise, sun altitude is zero, and now P point overlaps with D point, and the sun is in the time of top, and sun altitude is 90 °, and P point overlaps with O point, and according to isometric projection principle, the total relation between OP and OD can be expressed as,
Wherein, α is the half at fish eye lens visual angle.In conjunction with solar azimuth A, can obtain sunny particular location coordinate in fish eye images and be,
X＝C
x+OD*sinA*(90°-H)/α
Y＝C
y+OD*cosA*(90°-H)/α
Wherein, in formula, X is the horizontal ordinate of solar core in fish eye images, and Y is ordinate, C
x, C
yfor the coordinate of fish eye images central point.
Although described hereinbefore for a kind of mode that adopts fish-eye full visual field sky visible images to obtain equipment how to obtain the central point of sun image, but be to be understood that, in other embodiments, also can adopt alternate manner to determine the central point of sun image.In one embodiment, in the time adopting the mode of the tracking sun to obtain local sky visible images, the central point of this part sky visible images can be considered the wherein central point of sun image.In another embodiment, also can directly carry out image processing to sky visible images, adopt the mode of image recognition to search for sun image and estimate its center position.
When determining after the center position of sun image in sky visible images, can set taking this center position as benchmark needed presumptive area.In one embodiment, this presumptive area is the border circular areas that starts to extend predetermined radii with the central point of sun image.In one embodiment, the size of this predetermined radii can be by observing and analyze obtained sky visible images or rule of thumb coming manually to preset.In other embodiments, this predetermined radii also can be set taking the radius of sun image as benchmark.For example, this predetermined radii can be 1.1～3 times of sun image radiuses, preferably 1.2～2 times of sun image radiuses.The radius of sun image can manually preset by observing and analyze sun image or rule of thumb coming.Or the radius of sun image also can obtain by the mode of computing machine graphics process, as the mode that adopts image recognition is searched for sun image and estimated its radius.For the ease of computing machine processing, the radius of aforementioned presumptive area and/or the radius of sun image can be taking the numbers of pixel as unit, be only in exemplary embodiment at one, sun image radius can be 200 pixels, and the radius of presumptive area can should be 300 pixels mutually.
After having determined needed presumptive area, can process this sky visible images with computing machine, in this predetermined areas, search for each pixel, judge whether each pixel is high luminance pixel, and the quantity of high luminance pixel is counted.In this application, high luminance pixel refers to that gray-scale value is more than or equal to the pixel of predetermined gray threshold; Correspondingly, to be less than the pixel of predetermined gray threshold be non-high luminance pixel to gray-scale value.What obtain when image acquisition equipment is during without 8 gray-scale maps of symbol, can set single gray threshold.In one embodiment, this gray threshold can be chosen between 200-255.When image acquisition equipment obtain be coloured image time, can set respectively identical or different gray thresholds for each Color Channel, or can change into a gray-scale map and set a gray threshold.
In a preferred embodiment, high luminance pixel counting step can be completed by computing machine completely automatically.For example, by after sky visible images input computing machine, can this image be analyzed and be processed with computing machine, calculate the center position of the sun image in sky visible images according to known parameters; Automatic search is each pixel within the scope of the predetermined radii of the center of circle taking this center position, the gray-scale value of each pixel and gray threshold compared, and to judge that whether each pixel is as high luminance pixel, and the quantity of adding up high luminance pixel.
matching step
Matching step is used for setting up the matching relation between quantity and the direct solar radiation intensity of the high luminance pixel in presumptive area in sky visible images.
In matching step, can utilize the regression fit relation between quantity and the direct solar radiation intensity of the high luminance pixel in the direct solar radiation intensity data sequences of long period scope inter-sync observation and corresponding sky Detection Method in Optical Image Sequences are analyzed the presumptive area of sky visible images.Direct solar radiation intensity data sequences can obtain by the means of prior art, for example, utilize direct solar radiation table directly to measure.For each sky visible images, its image obtain and the counting of quantity to the high luminance pixel in presumptive area wherein can be carried out according to the description in aforementioned image acquisition step and high luminance pixel counting step.
Like this, after the high luminance pixel quantity obtaining in a series of sky visible images and corresponding presumptive area, in conjunction with the direct solar radiation intensity data sequences of synchronization gain, can carry out regression fit analysis to the relation between high luminance pixel quantity and direct solar radiation intensity.Present inventor finds, presents obvious dull nonlinear characteristic between the two.In one embodiment, between the high luminance pixel quantity obtaining and corresponding direct solar radiation intensity, have good exponential relationship, fitting function is as follows:
y=a*e
bx+c
Wherein, y is the quantity of the high luminance pixel in presumptive area in sky visible images, and x is direct solar radiation intensity, a, and b, c is fitting coefficient.
In other embodiments, between the quantity of the high luminance pixel in sky visible images in presumptive area and corresponding direct solar radiation intensity, can be the matching relation of other form, the matching relation of for example polynomial function form.
Selection on presumptive area in sky visible images and also may affect the concrete form of matching relation on the selection of gray threshold.But, to those skilled in the art, after the direct solar radiation intensity data of the high luminance pixel incremental data in the presumptive area that obtains a series of sky visible images and correspondence, be easy to obtain by fitting algorithm the concrete form that reflects the fitting function of matching relation between the two.
direct solar radiation strength measurement method and device
Fig. 3 shows according to the process flow diagram of the direct solar radiation strength measurement method based on sky visible images of the present invention.
As shown in Figure 3, step 101 is matching step, and it can carry out according to the matching step of describing above, to set up the matching relation between quantity and the direct solar radiation intensity of the high luminance pixel in the presumptive area of sky visible images.
Step 102 is image acquisition step, and it can carry out according to the image acquisition step of describing above, to utilize image acquisition equipment to obtain the sky visible images of predetermined instant.It should be noted that, in step 102, obtain the condition of sky visible images, as aperture size and the time shutter etc. of image acquisition equipment, condition preferably and while obtaining sky visible images while carrying out matching in matching step 101 is consistent, to can use the most rightly determined matching relation in step 101 in subsequent step.
Step 103 is high luminance pixel counting step, and it can carry out according to the high luminance pixel counting step of describing above, so that the high luminance pixel in the presumptive area of search the sky visible images, and the quantity of high luminance pixel is counted.It should be noted that in step 103, should be consistent with setting while carrying out matching in step 101 for the selected of presumptive area and to the judgment criterion of high luminance pixel, to use the most rightly determined matching relation in step 101.
Step 104 is radiation intensity calculating step, in this step 104, based on the matching relation of setting up in advance in step 101, can calculate according to the quantity that obtains high luminance pixel in step 103 the direct solar radiation intensity of described predetermined instant (being the corresponding moment of sky visible images obtaining in step 102).
Here it should be noted that in some cases, in the time that direct solar radiation strength ratio is larger, for example in a certain bigger numerical (as 1000W/m
2) when above, the pixel in the presumptive area of sun visible images may be all high luminance pixel, like this, direct solar radiation strength measurement method of the present invention can be distinguished each direct solar radiation intensity on this numerical value.Therefore, in image acquisition step, preferably image acquisition equipment is adjusted to like this, that is: for the arbitrary direct solar radiation intensity that is less than maximum possible direct solar radiation intensity, in the presumptive area of the sky visible images that image acquisition equipment obtains, comprises non-high luminance pixel.Like this, for arbitrary direct solar radiation intensity level, there is a different high luminance pixel quantitative value corresponding with it.
Can comprise the adjusting of image acquisition equipment: 1) in the time of imaging, with less aperture and shorter time shutter etc.; Or 2) before camera lens, increase optical filter, adjust light-inletting quantity.
Fig. 4 shows an embodiment of the direct solar radiation strength meter of carrying out this measuring method, and this device can comprise that full visual field sky image obtains equipment, sun image central point computing module, high luminance pixel counting module and radiation intensity and calculates module.Wherein, sun image central point computing module, high luminance pixel computing module and radiation intensity calculating module can be realized by the computing machine (as shown in the empty frame in Fig. 4) that specific program is housed.
Full visual field sky image obtains equipment for obtaining the full visual field sky visible images of predetermined instant.Then, by obtained full visual field sky visible images input computing machine.In computing machine, sun image central point computing module is according to the sun altitude in moment corresponding to this full visual field sky visible images and the position that the central point of the sun image in this image is calculated at position angle.High luminance pixel counting module is searched for gray-scale value in this full visual field sky visible images and is more than or equal to the high luminance pixel of predetermined gray threshold within the scope of the predetermined radii in the center of circle at the central point taking sun image, and the quantity of high luminance pixel is counted.Radiation intensity is calculated the matching relation between quantity and the direct solar radiation intensity of module based on predetermined high luminance pixel, calculates the direct solar radiation intensity of this predetermined instant according to the quantity of obtained high luminance pixel.
Direct solar radiation strength meter of the present invention can complete the measurement to direct solar radiation intensity automatically.
sunshine time measuring method
Fig. 5 shows according to the process flow diagram of the sunshine time measuring method based on sky visible images of the present invention.
As shown in Figure 5, step 201 is matching step, and it can carry out according to the matching step of describing above, to set up the matching relation between quantity and the direct solar radiation intensity of the high luminance pixel in the presumptive area of sky visible images.
Step 202 is image acquisition step, utilize image acquisition equipment within predetermined time with a series of sky visible images of predetermined time interval acquiring.For each sky visible images, can carry out according to the image acquisition step of describing above.It should be noted that, in step 202, obtain the condition of sky visible images, as aperture size and the time shutter etc. of image acquisition equipment, condition preferably and while obtaining sky visible images while carrying out matching in matching step 201 is consistent, to can use the most rightly determined matching relation in step 201 in subsequent step.
Step 203 is high luminance pixel counting step, searches for the high luminance pixel in the presumptive area of each sky visible images, and the quantity of high luminance pixel is counted.For each sky visible images, can carry out according to the high luminance pixel counting step of describing above.It should be noted that, in step 203, should be consistent with setting while carrying out matching in step 201 for the selected of the presumptive area of each sky visible images and to the judgment criterion of high luminance pixel, to use the most rightly determined matching relation in step 201.
Step 204 is determining steps at sunshine, for judging whether each sky visible images indicates sunshine.For a sky visible images, in the time that the quantity of the high luminance pixel obtaining in step 203 is more than or equal to predetermined high luminance pixel amount threshold, this sky visible images indicates sunshine; In the time that the quantity of the high luminance pixel obtaining in step 203 is less than this high luminance pixel amount threshold, this sky visible images represent all the time according to.Here, high luminance pixel amount threshold corresponds to a direct solar radiation intensity threshold.Conventionally,, in meteorological field, direct solar radiation intensity in other words irradiance meets or exceeds 120W/m
2time for there being sunshine, be less than 120W/m
2time represent all the time according to, therefore can be by 120W/m
2as direct solar radiation intensity threshold.According to this direct solar radiation intensity threshold, and matching relation based on definite in step 201, can calculate corresponding high luminance pixel amount threshold.
Step 205 is sunshine time calculation procedure, according to the size in the time interval of setting in step 202 and indicate that the quantity of the sky visible images at sunshine calculates sunshine time.In one embodiment, can will in obtain a series of sky visible images, indicate that the moment at sunshine is designated as 1, all the time according to moment be designated as 0, form a discrete information sequence at sunshine.In accumulation information sequence at sunshine, all 1 number of times occurring, is multiplied by this number of times the time interval of setting in step 202, can obtain the sunshine time of the time range setting in step 202.When the time range in step 202 is set as comprising from sun to sun whole when the duration, can calculate the sunshine time of whole day.
The measurement of number when sunshine time measuring method of the present invention can utilize computing machine automatically to complete counterglow.
Claims (11)
1. the sunshine time measuring method based on sky visible images, comprising:
Image acquisition step: utilize image acquisition equipment with a series of sky visible images of predetermined time interval acquiring;
High luminance pixel counting step: for each sky visible images, search for the high luminance pixel in its presumptive area, and the quantity of high luminance pixel is counted;
Sunshine determining step: for each sky visible images, judge whether it indicates sunshine; Wherein, in the time that the quantity of the high luminance pixel of described sky visible images is more than or equal to a high luminance pixel amount threshold, indicate sunshine; In the time that the quantity of the high luminance pixel of described sky visible images is less than described high luminance pixel amount threshold, represent all the time according to;
Sunshine time calculation procedure: according to the size in the described time interval and indicate that the quantity of the sky visible images at sunshine calculates sunshine time.
2. sunshine time measuring method according to claim 1, it is characterized in that, also comprise high luminance pixel amount threshold determining step: the matching relation between quantity and the direct solar radiation intensity of the high luminance pixel based in presumptive area described in predetermined sky visible images, calculate corresponding high luminance pixel amount threshold according to a predetermined direct solar radiation intensity threshold.
3. sunshine time measuring method according to claim 1 and 2, is characterized in that, described presumptive area is the sun and the region in preset range around thereof in described sky visible images.
4. sunshine time measuring method according to claim 3, is characterized in that, described presumptive area is the border circular areas that the central point of the sun image from described sky visible images extends predetermined radii.
5. sunshine time measuring method according to claim 4, it is characterized in that, also comprise sun image central point determining step: for sky visible images described in each, the position of the central point of definite described sun image wherein in described sky visible images.
6. sunshine time measuring method according to claim 5, it is characterized in that, in described sun image central point determining step, for sky visible images described in each, according to elevation angle and the position angle with respect to described image acquisition equipment at the corresponding moment sun of this sky visible images, the position of the central point that calculates described sun image in this sky visible images.
7. sunshine time measuring method according to claim 4, is characterized in that, described predetermined radii is 1.1～3 times of radius of the sun image in described sky visible images.
8. sunshine time measuring method according to claim 1, is characterized in that, described high luminance pixel is the pixel that in described sky visible images, gray-scale value is more than or equal to predetermined gray threshold.
9. sunshine time measuring method according to claim 8, is characterized in that, described gray threshold is chosen between 200-255.
10. sunshine time measuring method according to claim 2, is characterized in that, described matching is closed and is
y＝a*e
bx+c
Wherein, y is the quantity of the high luminance pixel in described presumptive area, and x is direct solar radiation intensity, a, and b, c is fitting coefficient.
11. sunshine time measuring methods according to claim 7, is characterized in that, described predetermined radii is 1.2～2 times of radius of the sun image in described sky visible images.
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| CN201210199585.5A CN102721988B (en) | 2012-06-14 | 2012-06-14 | Sunshine duration measuring method based on sky visible-light images |
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| CN104849774B (en) * | 2015-04-17 | 2017-03-29 | 中国水产科学研究院东海水产研究所 | A kind of sun set/raise time measuring method comprising weather conditions |
| CN105116470A (en) * | 2015-06-29 | 2015-12-02 | 华北水利水电大学 | Sunshine duration calculation based on ground feature TIN model |
| CN105911614B (en) * | 2016-07-04 | 2018-08-07 | 南通大学 | A kind of sunshine time computational methods based on data buffer storage |
| CN106326191B (en) * | 2016-08-26 | 2018-09-21 | 河海大学 | A method of sunshine time is quantified based on weather forecast descriptive data |
| CN110109196B (en) * | 2019-05-09 | 2021-07-30 | 洛阳众智软件科技股份有限公司 | Sunlight analysis micro-area division method, device and equipment |
| CN110728333B (en) * | 2019-12-19 | 2020-06-12 | 广东博智林机器人有限公司 | Sunshine duration analysis method and device, electronic equipment and storage medium |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5510772A (en) * | 1992-08-07 | 1996-04-23 | Kidde-Graviner Limited | Flame detection method and apparatus |
| CN1664516A (en) * | 2005-03-22 | 2005-09-07 | 沈天行 | Solar energy in-situ detection method and system |
| JP2005331320A (en) * | 2004-05-19 | 2005-12-02 | Toudai Tlo Ltd | Sky factor and daylight hours calculation system and calculation program |
| JP2010230587A (en) * | 2009-03-27 | 2010-10-14 | Fujitsu Ltd | Apparatus, method and program for decision of fine weather in satellite image scene |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5510772A (en) * | 1992-08-07 | 1996-04-23 | Kidde-Graviner Limited | Flame detection method and apparatus |
| JP2005331320A (en) * | 2004-05-19 | 2005-12-02 | Toudai Tlo Ltd | Sky factor and daylight hours calculation system and calculation program |
| CN1664516A (en) * | 2005-03-22 | 2005-09-07 | 沈天行 | Solar energy in-situ detection method and system |
| JP2010230587A (en) * | 2009-03-27 | 2010-10-14 | Fujitsu Ltd | Apparatus, method and program for decision of fine weather in satellite image scene |
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