A kind of electrical equipment electric discharge ultraviolet imagery quantization parameter extracting method based on gray scale
Technical field
The present invention relates to technical field of data processing, specifically a kind of electrical equipment electric discharge ultraviolet imagery amount based on gray scale
Change parameter extracting method.
Background technique
After high-tension apparatus puts into operation, due to rough surface unevenness, filth, fault of construction, conductor poor contact etc.,
Equipment field strength distribution can be caused uneven, cause the electric discharge phenomena such as corona, electric arc.Conductor corona be surpass, UHV transmission line is led
An important factor for line selection type, if do not controlled in a reasonable range, conducting wire bloom will be to electromagnetic environment, transmission of electricity energy loss
Etc. impacting.Meanwhile if corona state modulator is too tight, Transmission Cost will be caused excessively high.Therefore in Transmission Line Design
Conductor corona performance needs to control in reasonable range.Meanwhile the appearance of corona means that equipment may deposit in terms of insulation
In weak link or defect, corona phenomenon is found in time and checks the safe operation of the electric discharge position and power of equipment to system
It is of great significance.Therefore, attention of the Partial Discharge Detecting Technology increasingly by electric power research mechanism, operation department.
Ultraviolet imagery is a kind of visual high-tension apparatus surface-discharge detection method, is had the advantage that with remote
Distance, running state information non-contact, real-time, that equipment is rapidly obtained in a manner of on-line checking;High resolution, image are straight
See, not by electromagnetic interference, safe and reliable and benefit output investment ratio is high the advantages that;It can be in the situation for not having a power failure, not sampling, do not disintegrate
The lower diagnostic analysis for carrying out failure.Wide application had been obtained in electric system high-tension apparatus discharge examination in recent years.
The index of current ultraviolet imager detection electric discharge is mainly number of photons and facula area.Number of photons is straight by instrument
Reading is connect, the number of photons and discharge capacity, gain, observed range of ultraviolet imager have extremely complex non-linear relation, with
Discharge capacity increases, and number of photons can first increase, then reduce, in practical projects using extremely difficult, and when detection zone exists
Number of photons can not describe the strength of discharge of each point when multiple point of discharges.Facula area method is first by ultraviolet image two-value
Change, region of discharge is indicated with binaryzation hot spot, calculates region of discharge hot spot using the quantization method of facula area
Pixel quantity, the strength of discharge in region of discharge are not different, the strength of discharge in region of discharge be defaulted as it is identical, and it is practical
Electrical equipment electric discharge, the strength of discharge of region of discharge can not be identical, and a dimension is lost in binarization
Initial data, therefore the simplification of this quadrat method will bring very big error to the quantitative description of electric discharge.
Summary of the invention
The electrical equipment that the purpose of the present invention is to provide a kind of based on gray scale discharges ultraviolet imagery quantization parameter extraction side
Method, to solve the problems mentioned in the above background technology.
To achieve the above object, the invention provides the following technical scheme:
A kind of electrical equipment electric discharge ultraviolet imagery quantization parameter extracting method based on gray scale, comprising the following steps:
Step 1: the selection of effective image, specifically includes:
1) the original ultraviolet image of each frame is extracted from original ultraviolet video by image processing software;
2) above-mentioned original ultraviolet image is subjected to greyscale transformation, in ultraviolet gray level image, grey scale pixel value be 0-255 it
Between value, black region grey scale pixel value is 0, and the grey scale pixel value of white area is 255, effective light spot choose outside pixel
Gray value all 0;
3) image after greyscale transformation binary transform: is respectively converted into binary image to divide spot area;
4) mathematical morphology filter;
5) it interferes filtering out for hot spot: filtering out the small light spot far from main spot, obtain the selection of effective light spot;
Step 2: the equivalent facula area based on gamma weighting calculates, specifically include:
1. selecting effective region on original uv-spectrogram by the selection of effective image, and by other area pixels
It sets black;
2. gray processing is handled, in ultraviolet gray level image, value of the grey scale pixel value between 0-255, and black region pixel
Gray value is 0, and the grey scale pixel value of white area is 255, the gray value all 0 of the pixel outside effective light spot selection;
3. calculating equivalent facula area:
If intensity-weighted coefficient is X (x, y), the gray value of each pixel is G (x, y), and equivalent facula area is S:
In formula: M and N is the line number and columns of image array respectively;XiIt is the intensity-weighted coefficient of ith pixel point, etc.
Effect facula area S be exactly by the number of pixels of filtered region of discharge and the cumulative of weighting coefficient and.
As a further solution of the present invention: in the binary image, the small light spot far from electric discharge main spot is considered
Noise jamming.
As a further solution of the present invention: the step 5) specifically includes: by filtered uv-spectrogram, determining each
The size of a hot spot and length apart from main spot, if the threshold value that zonule hot spot filters out is S0, each hot spot and key light
The distance of spot is Li, when small light spot is more than threshold value L apart from main spot distance0And small light spot area is less than S0When, assert that the hot spot is
Hot spot is interfered, is eliminated, effective uv-spectrogram region can be obtained after treatment.
Compared with prior art, the beneficial effects of the present invention are:
The present invention carries out the description of region of discharge using the hot spot with gray value, and the size of gray value characterizes putting for the region
The size of electricity, it is strong and weak to solve the problems, such as not describing discharge capacity in region of discharge in the past in this way, it also will be more accurate
Describe the strength of discharge of electrical equipment and the position of electric discharge.The electric discharge overall strength of region of discharge can be described as gamma and add
Weigh facula area, the discharge capacity in the more accurate description region.
Detailed description of the invention
Fig. 1 is the flow chart of the first step in the pretreatment of ultraviolet image.
Fig. 2 is the flow chart of second step in the pretreatment of ultraviolet image.
Fig. 3 is transmission line of electricity corona discharge ultraviolet video processing result schematic diagram.
Fig. 4 is 10*720 split conductor corona discharge facula area and voltage curve figure when threshold value is smaller.
Fig. 5 is 10*720 split conductor corona discharge facula area and voltage curve figure when threshold value is larger.
Fig. 6 is the 10*720 split conductor corona discharge facula area and voltage relationship under the different condition based on gray processing
Curve graph.
Specific embodiment
The technical solution of the patent is explained in further detail With reference to embodiment.
Please referring to Fig. 1-6, a kind of electrical equipment based on gray scale discharges ultraviolet imagery quantization parameter extracting method, including with
Lower step:
(1) pretreatment of ultraviolet image
Ultraviolet imager shooting data include visible light video and ultraviolet light video, ultraviolet imager show visible light and
UV fusion video, to the positioning of failure and the aiming of camera, in order to more convenient simple when data processing, the present invention is only handled
Ultraviolet PASS VIDEO.The pretreatment process of ultraviolet image is as depicted in figs. 1 and 2.
The pretreatment of ultraviolet image the following steps are included:
Step 1: the selection of effective image, specifically includes:
1) the original ultraviolet image of each frame is extracted from original ultraviolet video by image processing software;
2) above-mentioned original ultraviolet image is subjected to greyscale transformation, in ultraviolet gray level image, grey scale pixel value be 0-255 it
Between value, black region grey scale pixel value is 0, and the grey scale pixel value of white area is 255, effective light spot choose outside pixel
Gray value all 0;
3) image after greyscale transformation binary transform: is respectively converted into binary image to divide spot area;And
In binary image, the small light spot far from electric discharge main spot is regarded as noise jamming;
4) mathematical morphology filter;
5) it interferes filtering out for hot spot: by filtered uv-spectrogram, determining the size of each hot spot and apart from master
The length of hot spot, if the threshold value that zonule hot spot filters out is S0, each hot spot is L at a distance from main spoti, when small light spot distance
Main spot distance is more than threshold value L0And small light spot area is less than S0When, it can be assumed that the hot spot is interference hot spot, eliminated, is passed through
Effective uv-spectrogram region can be obtained after crossing processing;
Step 2: the equivalent facula area based on gamma weighting calculates, specifically include:
1. selecting effective region on original uv-spectrogram by the selection of effective image, and by other area pixels
It sets black;
2. gray processing is handled, in ultraviolet gray level image, value of the grey scale pixel value between 0-255, and black region pixel
Gray value is 0, and the grey scale pixel value of white area is 255, the gray value all 0 of the pixel outside effective light spot selection;
3. calculating equivalent facula area:
Define the intensity-weighted that the weighting ultraviolet hot spot area based on gamma is each pixel and the pixel
The cumulative summation of coefficient product;If intensity-weighted coefficient is X (x, y), the gray value of each pixel is Gi, equivalent hot spot face
Product is S:
In formula: M and N is the line number and columns of image array respectively;XiIt is the intensity-weighted coefficient of ith pixel point, etc.
Effect facula area S be exactly by the number of pixels of filtered region of discharge and the cumulative of weighting coefficient and.
Experimental example 1
It is illustrated in figure 3 transmission line of electricity corona discharge ultraviolet video processing result schematic diagram, the left side is that ultraviolet video is a certain
The original image of frame, the right are the filtered image of the frame image, and by gray processing, equivalent facula area, which is calculated, is
10878.8549, therewith as a comparison, if using the equivalent facula area calculation method of binaryzation, obtained equivalent hot spot face
Product is 13310.7569.
Experimental example 2
Extraction algorithm error analysis
Error in ultraviolet equivalent facula area calculating is from filtering processing and binary conversion treatment.Ultraviolet hot spot area
The electric discharge that size and gray value correspond to electrical equipment is strong and weak.
In filtering processing, in order to filter out disturbing factor, and effective light spot is not lost as far as possible, the present invention uses light
Two conditions of spot area and facula position.First, it is believed that large spot is effective light spot, and the small light spot near large spot is effective light
Spot.Therefore, it is only filtered out in filtering apart from the farther away small light spot of large spot, substantially reduces the introducing of error.Secondly, of the invention
The calculating that equivalent facula area is directly participated in using gray value contains complete discharge information relative to binary conversion treatment.Two
When value is handled, after a selected threshold value, weaker putting in piece image can a little be ignored, stronger electric discharge enhancing, this will
Unpredictable error can be brought, and when discharge capacity constantly changes, which needs constantly adjustment, and the selection to the threshold value will
The key factor that error is brought into can be become, bring difficulty to practical engineering application.And use gray scale value coefficient as equivalent hot spot
The weighting coefficient of areal calculation can eliminate this error, and more convenient in practical implementation.
The electric discharge uv-spectrogram analysis of 10*720 conductor corona is measured in Qinghai extra-high voltage Experimental Base by processing, is being used
When binaryzation mode carries out facula area calculating, threshold value selection when discharging weaker and stronger cannot be identical, is difficult to select.Such as figure
It is the equivalent facula area calculation method using binaryzation and the equivalent facula area calculation method two using gray processing shown in 4
10*720 split conductor corona discharge facula area and voltage curve figure under kind method, when selecting a threshold value, In
Electric discharge change from weak to strong during, it may appear that due to threshold value is unreasonable and bring error in data.It or as shown in figure 5, is to use
10* under the two methods of the equivalent facula area calculation method of binaryzation and equivalent facula area calculation method of use gray processing
720 split conductor corona discharge facula areas and voltage curve figure, when the threshold value of selection compares conjunction when discharging stronger
Reason, then just will appear when discharging weaker due to Threshold bring error in data.
Experimental example 3
Using this method obtain 10*LGJ-720 conducting wire respectively in drying, drench with rain and three kinds of different conditions of wet conducting wire under electricity
Corona intensity.As a result see Fig. 6, can be seemed by Fig. 6, with the growth of voltage, corona discharge facula area is also increased,
It tallies with the actual situation, to confirm using the gray level image quantization parameter than using the scientific and accurate of binaryzation parameter
Property.
Rationally, the present invention uses band for the electrical equipment electric discharge ultraviolet imagery quantization parameter extracting method design based on gray scale
The hot spot of gray value carries out the description of region of discharge, and the size of gray value characterizes the size of the discharge capacity in the region, in this way to
It solves the problems, such as not describing discharge capacity power in region of discharge in the past, more accurate is also described into the electric discharge of electrical equipment
The position of intensity and electric discharge;The electric discharge overall strength of region of discharge can be described as gamma weighting facula area, more accurate
Description the region discharge capacity.
The preferred embodiment of the patent is described in detail above, but this patent is not limited to above-mentioned embodiment party
Formula within the knowledge of one of ordinary skill in the art can also be under the premise of not departing from this patent objective
It makes a variety of changes.