CN105528586A - Background filtering method for detecting and positioning mountain underground building by using double time phases - Google Patents

Abstract

The invention discloses a background filtering method for detecting and positioning a mountain underground building by using double time phases. The method comprises three steps: filter preprocessing of an infrared image, coarse detection of an underground building on the low level of pixel gray values of the infrared image and optimized accurate detection with an 'onion peeling' algorithm, and specifically comprises the steps of acquiring double time phase infrared images of the day and the night, wherein the night infrared image is used as a background field; performing double-edge filtration on the day infrared image to remove noise, performing cluster analysis to detect a suspected target area, coarsely detecting an underground building area in the suspected target area by using a cut-off algorithm based on adjacent pixels, filtering the background of the suspected target area section by section by using the coarsely detected underground building area as an optimization criterion, and uncovering the mountain of the area layer by layer by using the 'onion peeling' algorithm till furthest accurately detecting the underground building. The method solves the difficulty in acquiring infrared images of multiple time phases, and can be used for accurately detecting deep underground buildings.

Description

Utilize the background filtering method of hypogee in two phase Detection location massif

Technical field

The invention belongs to the technical field that physical geography, thermophysics and information processing intersect, more specifically, relate to a kind of background filtering method utilizing hypogee in two phase Detection location massif.

Background technology

In recent years, because various subterranean resource, mineral resources and underground water need, build a large amount of hypogees, hypogee Detection Techniques are subject to extensive concern.Various hypogee is distributed, has heat radiation, is different from the thermal source of background, the resource temperature of underground higher than/lower than massif background, think underground thermal source/low-temperature receiver.Conventional remote sensing only realizes the conditional object on earth's surface or on the water surface, and the echo signal being only only applicable to shallow-layer is only subject to the detection process of the decay of air dielectric; But the remote sensing of multi-dielectric deep layer is faced with the Multiple decrements process that echo signal is subject to air, solid and water body medium, the multiple distortion process of the characteristic of medium itself and air, solid and water body medium.Final signal becomes very faint, cannot detect by existing conventional method at all.At present, mainly concentrate on the target under shallow-layer target, small scale underground thermal source target and shallow-layer target multi-temporal image to the detection of hypogee, the research detected further object (buried depth > 10m) is less.

Summary of the invention

For above defect or the Improvement requirement of prior art, the invention provides a kind of background filtering method utilizing hypogee in two phase Detection location massif, avoid the problem that the infrared figure of multidate obtains difficulty, can detect that deeper subsurface is built exactly.

For achieving the above object, the invention provides a kind of background filtering method utilizing hypogee in two phase Detection location massif, it is characterized in that, comprise the steps:

(1) the infrared figure of two round the clock phases comprising hypogee is obtained;

(2) the low bit getting its grey scale pixel value to figure infrared between daytime carries out the rough detection of hypogee, obtains the area in suspected target region;

Comprise the steps: further

(2-1) bilateral filtering is carried out to figure infrared between daytime, remove noise;

(2-2) large scale cluster analysis is carried out to figure infrared between the daytime after bilateral filtering, detect suspected target region;

(2-3) the cut position process based on neighborhood pixels is carried out to suspected target region, obtain the area in suspected target region;

(3) background filtering is carried out to suspected target area segmentation, obtain the thermal radiation field of hypogee, regulate the area of the thermal radiation field of hypogee, make it closest to the area in suspected target region, realize the detection and location to hypogee.

Preferably, described step (2-2) comprises the steps: further

(2-2-1) be multiple polygonal region by diagram root infrared between the daytime after bilateral filtering, using the gray average of each polygonal region as a sample block;

(2-2-2) the distance ratio of all sample block is calculated;

Wherein, i-th sample block b _idistance ratio s is the number of sample block, and d () represents the distance of two sample block;

(2-2-3) make the sequence number q=1 of class, chosen distance is than the class heart m of minimum sample block as first class ₁;

(2-2-4) be assigned to all sample block from its nearest class in all q class, and upgrade the class heart of all q class, wherein, the class heart of a kth class is k=1 ..., q, N _kthe sample number of a kth class, b _kjrepresent a jth sample block of a kth class;

(2-2-5) make q=q+1, judge whether q is greater than 2, be then using gray-scale value the greater graph of a correspondence region in first class and second class as suspected target region, otherwise order perform step (2-2-6):

(2-2-6) acquisition makes minimum sample block, it can be used as the class heart of q class, returns step (2-2-4).

Preferably, in described step (2-3), with the window traversal suspected target region that size is w*h, grey scale pixel value in window is done mutually and computing, according to operation result, to the pixel assignment again in suspected target region, obtain the fringe region of hypogee, add up the number of pixels in this region, obtain the area in suspected target region.

Preferably, the thermal radiation field of hypogee is:

$(x,y,z,t)=\mathrm{BT}(x,y,z,t)\underset{l=1}{\overset{n}{\∑}}{k}_l{E}_l,$

Wherein, k _lfor the weight coefficient of l height above sea level section in suspected target region of infrared figure in place, hypogee massif evening, E _lrepresent the gray average of l the height above sea level section in the suspected target region of place, hypogee massif infrared figure in evening, n is the height above sea level hop count amount in suspected target region of infrared figure in place, hypogee massif evening, BT (x, y, z, t) be infrared figure on place, hypogee massif daytime, (x, y, z) be volume coordinate, t is the time; By adjustment k _lvalue, regulate the area of thermal radiation field of hypogee.

In general, the above technical scheme conceived by the present invention compared with prior art, there is following beneficial effect: comprise infrared image filter preprocessing, the low level getting its grey scale pixel value to infrared image carries out the rough detection of hypogee and " stripping onion " algorithm optimizing accurately detects three steps, by obtaining the infrared figure of two phases on daytime and evening, by infrared for evening figure field as a setting, first bilateral filtering process is carried out to infrared figure on daytime and remove noise, carry out cluster analysis again, detect suspected target region, the cut position algorithm process based on neighborhood pixels is utilized to detect roughly region, hypogee to suspected target region, using the hypogee area of rough detection as optimization criterion, section is distinguished to suspected target and carries out background filtering, " stripping onion " algorithm is utilized to open the massif in this region from level to level, until at utmost accurately detect hypogee.The present invention utilizes two infrared figure of phase to realize Detection location, avoids the problem that the infrared figure of multidate obtains difficulty, can detect that deeper subsurface is built exactly.

Accompanying drawing explanation

Fig. 1 is the background filtering method process flow diagram of hypogee in the two phase Detection location massif of utilization of the embodiment of the present invention;

Fig. 2 is analogy man mountain infrared figure in evening;

Fig. 3 is analogy man mountain infrared figure on daytime;

Fig. 4 is the structural representation of analogy man mountain underground installation;

Fig. 5 is analogy man's mountain infrared figure object block on daytime result of detection and descends situation of building to contrast truly;

Fig. 6 is analogy man mountain sunny side on daytime/back infrared image sample block intensity profile figure, and wherein, (a) is sunny side, and (b) is the back;

Fig. 7 be based on the cut position process of neighborhood pixels after target area on daytime, analogy man mountain testing result;

Fig. 8 is analogy man mountain target area marker on daytime result;

Fig. 9 carries out background filtering schematic diagram to suspected target area segmentation;

Figure 10 is the result that " stripping onion " algorithm successively " opens " stratum;

Figure 11 target area area optimizing testing result.

Embodiment

In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.In addition, if below in described each embodiment of the present invention involved technical characteristic do not form conflict each other and just can mutually combine.

As shown in Figure 1, be described to explain a mountain, in the two phase Detection location massif of utilization of the embodiment of the present invention, the background filtering method of hypogee comprises the steps:

(1) the infrared figure of two round the clock phases comprising hypogee is obtained;

As shown in Figure 2, be analogy man mountain infrared figure in evening; As shown in Figure 3, be analogy man mountain infrared figure on daytime.Under the analogy man mountain in this region, have underground installation, its structural representation as shown in Figure 4.

(2) the low bit getting its grey scale pixel value to figure infrared between daytime carries out the rough detection of hypogee, obtains the area in suspected target region.Comprise the steps: further

(2-1) bilateral filtering is carried out to figure infrared between daytime, remove noise.

Bilateral filtering is a kind of wave filter can protecting limit denoising, why can reach this denoising effect, be because wave filter is made up of two functions, a function determines filter coefficient by geometric space distance, and another determines filter coefficient by pixel value difference.

In two-sided filter, the value of output pixel depends on the weighted array of the value of neighborhood territory pixel,

weight coefficient w (i, j, k, l) depends on field of definition core with codomain core product

$(i,j,k,l)\exp (-\frac{{(i-k)}^2+{(j-l)}^2}{{2\mathrm{\σ}}_d^2}-\frac{\left|\right|f(i,j)-f(k,l){\left|\right|}^2}{{2\mathrm{\σ}}_r^2})$

Consider the difference of spatial domain and codomain simultaneously.

Two-sided filter can the noise of the filtering analogy man infrared figure in mountain, retains the faint signal in hypogee simultaneously, carries out two-sided filter process, achieve good result in an experiment to the analogy man infrared figure in mountain.

(2-2) large scale cluster analysis is carried out to figure infrared between the daytime after bilateral filtering, detect suspected target region.

In the two round the clock phase analogy man infrared figure in mountain obtained, the analogy man infrared figure in mountain in evening is regarded background information field by us, by the analogy man infrared figure in mountain on daytime as target context information field, but still preserve faint hypogee information in the analogy man infrared figure in mountain at night, because the signal of deeper subsurface building is inherently very faint, we need to retain hypogee signal as far as possible, therefore, first large scale detects suspected target region, when the man infrared figure in mountain of two phase analogy round the clock subtracts each other, suspected target region is done and carefully subtracts each other process.First, the Detection Based on Clustering that large scale detects suspected target region is introduced.

In infrared image, the gray average of sample is a kind of feature can effectively distinguished down with/without hypogee, so, here direct several apex coordinates by providing each sample block, calculate the coordinate of the pixel in its polygon surrounded, take out the gray-scale value of its correspondence position, thus obtain the gray average of this sample block, utilize space constraint means clustering algorithm to obtain the mark result of each sample block.

Comprise the steps: further

(2-2-1) be multiple polygonal region by diagram root infrared between the daytime after bilateral filtering, the gray average of each polygonal region is as a sample block.

(2-2-2) the distance ratio of all sample block is calculated;

Wherein, i-th sample block b _idistance ratio s is the number of sample block, and d () represents the distance of two sample block.

(2-2-3) make the sequence number q=1 of class, chosen distance is than the class heart m of minimum sample block as first class ₁.

(2-2-4) be assigned to all sample block from its nearest class in all q class, and upgrade the class heart of all q class, wherein, the class heart of a kth class is k=1 ..., q, N _kthe sample number of a kth class, b _kjrepresent a jth sample block of a kth class.

(2-2-5) make q=q+1, judge whether q is greater than 2, is, algorithm terminates, otherwise order performs step (2-2-6).

(2-2-6) acquisition makes minimum sample block, it can be used as the class heart of q class, returns step (2-2-4).

Obtain the result after cluster by above formula, large that class of gray-scale value is as a class of doubtful hypogee, and the little class of gray-scale value is as a class of non-doubtful hypogee.The position of hypogee is obtained finally by space constraint clustering algorithm.

Because the heat that there is distributed deeper subsurface construction area can be delivered to the surface of massif through the heat modulation of rock, soil and vegetation, being reflected to will be variant with the gray-scale value around without the region of hypogee in gray level image, therefore according to its different gray difference by its cluster, result is as shown in Figure 5.

The region highlighted is the position, hypogee that cluster obtains, redness is position, real hypogee, those standard deviations between class in its class of further analysis, result shows that class internal standard difference is significantly less than standard deviation between class, has the regional average value of hypogee daytime higher than the average without hypogee block.Explain family mountain infrared figure target fast statistics daytime as shown in the figure, wherein, between class distance is the difference of average in two class classes, sunny side to have in the class of hypogee average 30191 > without average 30141 in the class of hypogee, and the back to have in the class of hypogee average 29974 > without average 29946 in the class of hypogee.

dis _{between_class}＝|mean _{with_target}-mean _{with_target}|

Following table is analogy man mountain infrared image on daytime sample block recognition result statistics.

As can be seen from the above table, no matter be the gray average (30214 having the sample block of hypogee under the analogy man ubac face or sunny side taken daytime, 29978) gray average (30154 of the lower sample block without hypogee is obviously greater than, 29952), but the gray average of the gray average of sunny side sample block apparently higher than back sample block can be found out from gray average, if directly all sample block are carried out the sample block that cluster will be identified as down the sample block without hypogee under some sunny sides hypogee cause higher false alarm rate so do not distinguish male and female face.In addition, under have the class internal standard of hypogee sample block difference and the lower class internal standard without hypogee sample block gray average difference to be all significantly less than the between class distance of two classes, with have at present hypogee sample block the poor class internal standard be slightly less than again without hypogee sample block of class internal standard poor.If Fig. 6 (a) and Fig. 6 (b) is analogy man's mountain sunny side on daytime and back infrared image sample block intensity profile figure respectively.

(2-3) the cut position process based on neighborhood pixels is carried out to suspected target region, obtain the area in suspected target region.

The feeble signal of deeper subsurface building is mainly reflected in the low bit of whole gradation of image, so the higher bit position of the mode filtering image that can be processed by position, by background filtering, is highlighted hypogee.

Particularly, be the window traversal suspected target region of w*h by size, the grey scale pixel value in window done mutually and computing, according to operation result, to the pixel assignment again in suspected target region.By with computing and pixel assignment again, detected roughly the fringe region of hypogee, add up the number of pixels in this region, the area S in the region, hypogee detected roughly.

Img is region, doubtful hypogee, and its size is c*r.

In the image coordinate system in suspected target region, be the window of (u, v) to center point coordinate, itself and operation result can be expressed as:

result＝img(u-h/2，v-w/2)&img(u-h/2，v-w/2+1)&…&img(u，v)&…

&img(u+h/2，v+w/2)；1＜u＜r，1＜v＜c

If result=0, then img (u, v)=0, otherwise img (u, v)=img (u, v)-result.

Analyze above formula, if window is background entirely or is target area entirely, so with rear, result change is little, img (u, v)=0; If in window be noise, so with rear result=0, img (u, v)=0; If window portion is divided into target area, part is background, because target area can be similar to the superposition regarding hypogee information field and background information field as, whole template area phase with after, be background information field, img (u, v)=img (u, v)-result, then img (u, v) be hypogee information field, so just detected roughly the fringe region of hypogee.

As Fig. 7 be based on the cut position process of neighborhood pixels after target area on daytime, analogy man mountain testing result, if Fig. 8 is analogy man mountain target area marker on daytime result.

(3) with " stripping onion " algorithm, suspected target region is accurately detected: carry out background filtering to the suspected target area segmentation of infrared figure between place, hypogee massif daytime, the thermal radiation field obtaining hypogee is:

$(x,y,z,t)=\mathrm{BT}(x,y,z,t)\underset{l=1}{\overset{n}{\∑}}{k}_l{E}_l$

Wherein, k _lfor the weight coefficient of l height above sea level section in suspected target region of infrared figure in place, hypogee massif evening, E _lrepresent the gray average of l the height above sea level section in the suspected target region of place, hypogee massif infrared figure in evening, n is the height above sea level hop count amount in suspected target region of infrared figure in place, hypogee massif evening, BT (x, y, z, t) be infrared figure on place, hypogee massif daytime, (x, y, z) be volume coordinate, t is the time.

By adjustment k _lvalue, make the area of the thermal radiation field of hypogee closest to the area S in the region, hypogee detected roughly in (2-3), thus accurate detection and location realized to hypogee.

According to sea level elevation segmentation; think that the landform thermo parameters method of identical height above sea level is roughly the same; because infrared figure in evening includes the information field of hypogee equally; to place, hypogee massif evening, the identical height above sea level section of infrared figure is got average and is carried out background filtering again; like this can in filtering containment objective information, simultaneously also can be similar to real landform Temperature Distribution.The target area explaining family mountain the daytime detected in (2-2) is carried out to the background filtering of layering, progressively find the signal of target to show the strongest level.As Fig. 9 carries out background filtering schematic diagram to suspected target area segmentation.

If Figure 10 is the result that " stripping onion " algorithm " opens " stratum from level to level, after adding the optimization criterion of target area area, final testing result as shown in figure 11.

Those skilled in the art will readily understand; the foregoing is only preferred embodiment of the present invention; not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.

Claims (4)

1. utilize a background filtering method for hypogee in two phase Detection location massif, it is characterized in that, comprise the steps:

(1) the infrared figure of two round the clock phases comprising hypogee is obtained;

(2) the low bit getting its grey scale pixel value to figure infrared between daytime carries out the rough detection of hypogee, obtains the area in suspected target region;

Comprise the steps: further

(2-1) bilateral filtering is carried out to figure infrared between daytime, remove noise;

(2-2) large scale cluster analysis is carried out to figure infrared between the daytime after bilateral filtering, detect suspected target region;

(2-3) the cut position process based on neighborhood pixels is carried out to suspected target region, obtain the area in suspected target region;

(3) background filtering is carried out to suspected target area segmentation, obtain the thermal radiation field of hypogee, regulate the area of the thermal radiation field of hypogee, make it closest to the area in suspected target region, realize the detection and location to hypogee.

2. the background filtering method utilizing hypogee in two phase Detection location massif as claimed in claim 1, it is characterized in that, described step (2-2) comprises the steps: further

(2-2-1) be multiple polygonal region by diagram root infrared between the daytime after bilateral filtering, using the gray average of each polygonal region as a sample block;

(2-2-2) the distance ratio of all sample block is calculated;

Wherein, i-th sample block b _idistance ratio s is the number of sample block, and d () represents the distance of two sample block;

(2-2-3) make the sequence number q=1 of class, chosen distance is than the class heart m of minimum sample block as first class ₁;

(2-2-4) be assigned to all sample block from its nearest class in all q class, and upgrade the class heart of all q class, wherein, the class heart of a kth class is k=1 ..., q, N _kthe sample number of a kth class, b _kjrepresent a jth sample block of a kth class;

(2-2-5) make q=q+1, judge whether q is greater than 2, be then using gray-scale value the greater graph of a correspondence region in first class and second class as suspected target region, otherwise order perform step (2-2-6);

(2-2-6) acquisition makes minimum sample block, it can be used as the class heart of q class, returns step (2-2-4).

3. the background filtering method utilizing hypogee in two phase Detection location massif as claimed in claim 1 or 2, it is characterized in that, in described step (2-3), of the window traversal suspected target region that size is w*h, the grey scale pixel value in window is made mutually and computing, according to operation result, to the pixel assignment again in suspected target region, obtain the fringe region of hypogee, add up the number of pixels in this region, obtain the area in suspected target region.

4. the background filtering method utilizing hypogee in two phase Detection location massif as claimed in claim 1 or 2, it is characterized in that, the thermal radiation field of hypogee is:

$T(x,y,z,t)=BT(x,y,z,t)-\underset{l=1}{\overset{n}{\Σ}}{k}_l{E}_l,$

Wherein, k _lfor the weight coefficient of l height above sea level section in suspected target region of infrared figure in place, hypogee massif evening, E _lrepresent the gray average of l the height above sea level section in the suspected target region of place, hypogee massif infrared figure in evening, n is the height above sea level hop count amount in suspected target region of infrared figure in place, hypogee massif evening, BT (x, y, z, t) be infrared figure on place, hypogee massif daytime, (x, y, z) be volume coordinate, t is the time; By adjustment k _lvalue, regulate the area of thermal radiation field of hypogee.