CN105657428A - Infrared image compression method and system applied to contact network - Google Patents

Abstract

The invention discloses an infrared image compression method and an infrared image compression system applied to a contact network; the method comprises the following steps: S1, obtaining an infrared temperature image stream; S2, successively taking out each frame infrared temperature image in the infrared temperature image stream; S3, judging whether the current frame infrared temperature image is a first frame image of the infrared temperature image stream; S4, creating a blank infrared video compressed file and a corresponding blank index file, and writing a file header in the index file; S5, carrying out compression processing as well as frame information generation and writing on the infrared temperature image; and S6, judging whether the current frame infrared temperature image is a last frame image of the infrared temperature image stream. According to the infrared image compression method and the infrared image compression system applied to the contact network provided by the invention, through carrying out the compression processing on each frame infrared temperature image in the infrared temperature image stream collected by an infrared camera, the space for storing the infrared temperature image stream is reduced.

Description

A kind of IR image compression method and system suitable in contact net

Technical field

The present invention relates to a kind of IR image compression method and system suitable in contact net.

Background technology

Railway contact line is that railroad train (locomotive and motor-car) provides reliable continual electric energy, transmits electric energy by supply lines and pantograph (abbreviation bow net) to train; Supply lines lead high level and stagger is the important parameter of contact net operation monitoring, common computational methods are the images of first shooting pantograph and supply lines contact site, go out to lead high level and stagger again through image analysis calculation; Utilize thermal infrared imaging equipment shooting bow net image, do not limited by light environment round the clock, by focusing, the infrared temperature data at bow net position can be accurately acquired.

Bow net infrared image is really temperature data matrix, and pixel value is the temperature value of corresponding pixel points; Because temperature data is likely to there is negative value, particularly in the winter time, and computer for the pixel value of image that shows on the occasion of, so the infrared image directly obtained cannot directly display; Because temperature data would be likely to occur bigger span, such as photographed the solar time, temperature values is likely 20 degrees Celsius to 300 degrees Celsius, and now bow net spot temperature value is likely 20 degrees Celsius to 40 degrees Celsius, after temperature data matrix conversion becomes gray level image, the pixel value at bow net position is less to be positioned near null value, and bow net position shows and tends to black, not easily sees clearly. In addition to obtain higher precision, the types of variables storing temperature value in computer is generally 16 word width, and the types of variables of the pixel value of gray level image is 8 word width, if the infrared image that directly 16 words of storage are wide, later stage is loaded into and after reading data, need again infrared image wide for 16 words to be converted to 8 wide gray level images of word, thus reducing speed and the efficiency of image procossing.

Summary of the invention

It is an object of the invention to overcome the deficiencies in the prior art, a kind of IR image compression method and system suitable in contact net are provided, in the infrared temperature image stream that infrared camera is collected, each frame infrared temperature image is compressed processing, and reduces infrared temperature image stream storage requisite space.

It is an object of the invention to be achieved through the following technical solutions: a kind of IR image compression method suitable in contact net, comprise the following steps:

S1. from infrared camera, obtain infrared temperature image stream;

S2. each frame infrared temperature image in infrared temperature image stream is taken out successively according to the time order and function order of infrared camera shooting;

S3. judge that whether present frame infrared temperature image is the first two field picture of infrared temperature image stream:

(1) if present frame infrared temperature image is the first two field picture of infrared temperature image stream, step S4 is jumped to;

(2) if present frame infrared temperature image is not the first two field picture of infrared temperature image stream, step S5 is jumped to;

S4. create the infrared video compressed file of blank and the index file that correspondence is blank, and indexed file writes file header;

S5. it is compressed present frame infrared temperature image processing, obtains the compression picture frame of present frame, and compression picture frame is write in infrared video compressed file with additional pattern; It is the frame information of the compression picture frame generation correspondence of present frame simultaneously, and the frame information generated is write in index file with additional pattern;

S6. judge that whether present frame infrared temperature image is the last frame image of infrared temperature image stream:

(1) if present frame infrared temperature image is the last frame image of infrared temperature image stream, this second compression terminates;

(2) if present frame infrared temperature image is the last frame image of infrared temperature image stream, jump to step S3, next frame infrared temperature image is carried out the operation of step S3��S6.

Described step S4 includes following sub-step:

S41. the infrared video compressed file of blank and the index file that correspondence is blank are created;

S42. writing file header in indexed file, the file header of write includes picture traverse information and the picture altitude information of infrared video compressed file.

Described step S5 includes following sub-step:

S51. the infrared temperature data of present frame infrared temperature image are obtained;

S52. to present frame infrared temperature image statistics temperature data and generate temperature rectangular histogram;

S53. present frame infrared temperature image is converted to infrared hybrid optical system;

S54. infrared hybrid optical system is carried out high temperature and low temp compensating, then promotes room temperature band contrast, obtain grey level compensation image;

S55. form the compression picture frame of present frame infrared temperature image, compression picture frame is write in infrared video compressed file with additional pattern;

The frame number compressing picture frame in infrared video compressed file starts counting up from 0, and the frame number of the 1st frame is 0, the frame number 1 of the 2nd frame, and the frame number of the i-th frame is i-1, i is the integer more than 0 less than totalframes.

Described compression picture frame includes including successively from front to back: jpeg image that compression obtains, acquiescence rectangle frame upper left lower right coordinate, acquiescence rectangle frame maximum temperature point temperature value, temperature value array that acquiescence rectangle frame maximum temperature point coordinates is corresponding with infrared gray scale.

S56. it is the frame information of the compression picture frame generation correspondence of present frame, and the frame information generated is write in index file with additional pattern.

Described frame information includes the timestamp information of the data size information of compression picture frame, the compression picture frame start position information in compressed video file, compression picture frame shooting from front to back successively.

After compression of images, it is possible to search corresponding timestamp information according to frame number, or find the compression image that this frame number is corresponding in compressed video file, in like manner, by known timestamp information, it is also possible to try to achieve the frame number of correspondence.

Described step S52 includes following sub-step:

S521. the statistics pixel sum n of present frame infrared temperature image, maximum temperature maxT, minimum temperature minT, high temperature dot number highc and low temperature are counted out lowc;

S522. definition present frame infrared temperature image is image A, if the height of image A is h, the width of image A is w, using the upper left corner of image A as initial point, set up pixel coordinate system, the row-coordinate i of pixel coordinate system increases from top to bottom successively, and the row coordinate j of pixel coordinate system increases from left to right successively, defines A (i, j) for pixel (i, j) temperature value at place, wherein 0��i��h-1,0��j��w-1;

S523. creating temperature rectangular histogram TA, and the transverse axis of temperature rectangular histogram TA is divided into 256 unit, element numerals x is integer, and 0��x��255, and the cell height H (x) of temperature rectangular histogram x unit is equal to the pixel number met the following conditions:

$x=\frac{A(i,j)-\min T}{\max T-\min T}*255;$

S524. temperature rectangular histogram transverse axis is divided into 1% low temperate zone, 98% room temperature band and 1% thermal zone, asks for the critical point lowx of low temperate zone and room temperature band, ask for room temperature band and thermal zone critical point highx.

Described step S53 includes: seek the gray value that in image A, each pixel is corresponding, obtain infrared hybrid optical system GA: pixel (i, j) corresponding gray value GA (i, j), equal to pixel (i, j) temperature value A (i, j) element numerals corresponding in temperature rectangular histogram.

Described step S54 includes: according to each pixel in image GA (i, pixel value GA j) (and i, j) and the relation of lowx, highx, try to achieve correspondence grey level compensation value GAS (i, j), obtains grey level compensation image GAS:

(1) if GA (i, j) less than lowx, GAS, (i, j) takes 0;

(2) if GA (i, j) more than highx, GAS, (i, j) takes 255;

(3) if GA (i, j) between lowx and highx:

$GAS(i,j)=\frac{GA(i,j)-lowx}{highx-lowx}*255$

Described step S55 includes following sub-step:

S551. grey level compensation compression of images is become jpeg image, and preserves the temperature value array that gray value in grey level compensation image is corresponding;

S552. use acquiescence rectangle frame that jpeg image is carried out labelling in jpeg image;

S553. the upper left lower right coordinate of acquiescence rectangle frame, acquiescence rectangle frame maximum temperature point temperature value and acquiescence rectangle frame maximum temperature point coordinates are preserved;

S554. the temperature value array that the jpeg image of present frame is corresponding with acquiescence rectangle frame upper left lower right coordinate, acquiescence rectangle frame maximum temperature point temperature value, acquiescence rectangle frame maximum temperature point coordinates and infrared gray scale forms the compression picture frame of present frame.

Further, grey level compensation compression of images becomes in the process of jpeg image, the height of image and width do not change, corresponding pixel coordinate system is also without changing, and acquiescence rectangle frame upper left lower right coordinate, acquiescence rectangle frame maximum temperature point temperature value and acquiescence rectangle frame maximum temperature point coordinates are all based on the pixel coordinate system in grey level compensation image.

Further, give tacit consent to rectangle frame, refer to artificial setting acquiescence rectangle marked region, carry out labelling by a part of specific region of gained jpeg image according to being manually set.

A kind of IR Image Compression suitable in contact net, including data acquisition module and data processing module; Described data processing module includes infrared video compressed file creating unit, index file creation unit, compression processing unit and frame information and generates unit:

Described data acquisition module for obtaining infrared temperature image stream from infrared camera;

Described infrared video compressed file creating unit is for creating the infrared video compressed file of blank;

Described index file creation unit is for creating the index file of blank;

Described compression processing unit, for each frame infrared temperature image in infrared temperature image stream is processed, obtains the compression picture frame of present frame infrared temperature image, and writes in video compress file by compression picture frame with additional pattern;

Described frame information generates unit for the compression picture frame delta frame information for present frame infrared temperature image, and is write in index file with additional pattern by the frame information generated.

The invention has the beneficial effects as follows: in the infrared temperature image stream that infrared camera is collected by (1), each frame infrared temperature image is compressed processing, reduce infrared temperature image stream storage requisite space.

(2) the compression picture frame obtained for each frame infrared temperature image Compression generates corresponding index information, lays a good foundation for successive image process, analysis and identification.

(3) the unsharp problem of partial image region that infrared temperature data cause is solved with excessive temperature value and extremely low temperature value.

(4) problem that infrared temperature data cannot be used directly for Computer display with negative value is solved.

Accompanying drawing explanation

Fig. 1 is the flow chart of the present invention;

Fig. 2 is the system principle diagram of the present invention.

Detailed description of the invention

Below in conjunction with accompanying drawing, technical scheme is described in further detail, but protection scope of the present invention is not limited to the following stated.

As it is shown in figure 1, a kind of IR image compression method suitable in contact net, comprise the following steps:

S1. from infrared camera, obtain infrared temperature image stream;

S2. each frame infrared temperature image in infrared temperature image stream is taken out successively according to the time order and function order of infrared camera shooting;

S3. judge that whether present frame infrared temperature image is the first two field picture of infrared temperature image stream:

(1) if present frame infrared temperature image is the first two field picture of infrared temperature image stream, step S4 is jumped to;

(2) if present frame infrared temperature image is not the first two field picture of infrared temperature image stream, step S5 is jumped to;

S4. create the infrared video compressed file of blank and the index file that correspondence is blank, and indexed file writes file header;

S5. it is compressed present frame infrared temperature image processing, obtains the compression picture frame of present frame, and compression picture frame is write in infrared video compressed file with additional pattern; It is the frame information of the compression picture frame generation correspondence of present frame simultaneously, and the frame information generated is write in index file with additional pattern;

S6. judge that whether present frame infrared temperature image is the last frame image of infrared temperature image stream:

(1) if present frame infrared temperature image is the last frame image of infrared temperature image stream, this second compression terminates;

(2) if present frame infrared temperature image is the last frame image of infrared temperature image stream, jump to step S3, next frame infrared temperature image is carried out the operation of step S3��S6.

Described step S4 includes following sub-step:

S41. the infrared video compressed file of blank and the index file that correspondence is blank are created;

S42. writing file header in indexed file, the file header of write includes picture traverse information and the picture altitude information of infrared video compressed file.

Described step S5 includes following sub-step:

S51. the infrared temperature data of present frame infrared temperature image are obtained;

S52. to present frame infrared temperature image statistics temperature data and generate temperature rectangular histogram;

S53. present frame infrared temperature image is converted to infrared hybrid optical system;

S54. infrared hybrid optical system is carried out high temperature and low temp compensating, then promotes room temperature band contrast, obtain grey level compensation image;

S55. form the compression picture frame of present frame infrared temperature image, compression picture frame is write in infrared video compressed file with additional pattern;

Described compression picture frame includes including successively from front to back: jpeg image, 16 bytes that compression obtains give tacit consent to the temperature value array that rectangle frame upper left lower right coordinate, 4 bytes acquiescence rectangle frame maximum temperature point temperature values, 8 bytes acquiescence rectangle frame maximum temperature point coordinates and 256 grades of infrared gray scales of 512 bytes are corresponding.

S56. it is the frame information of the compression picture frame generation correspondence of present frame, and the frame information generated is write in index file with additional pattern.

Described frame information includes the timestamp information of the data size information of compression picture frame, the compression picture frame start position information in compressed video file, compression picture frame shooting from front to back successively.

After compression, it is possible to search corresponding timestamp information according to frame number, or find the compression image that this frame number is corresponding in compressed video file, in like manner, by known timestamp information, it is also possible to try to achieve the frame number of correspondence

Described step S52 includes following sub-step:

S521. the statistics pixel sum n of present frame infrared temperature image, maximum temperature maxT, minimum temperature minT, high temperature dot number highc and low temperature are counted out lowc;

S522. definition present frame infrared temperature image is image A, if the height of image A is h, the width of image A is w, using the upper left corner of image A as initial point, set up pixel coordinate system, the row-coordinate i of pixel coordinate system increases from top to bottom successively, and the row coordinate j of pixel coordinate system increases from left to right successively, defines A (i, j) for pixel (i, j) temperature value at place, wherein 0��i��h-1,0��j��w-1;

S523. creating temperature rectangular histogram TA, and the transverse axis of temperature rectangular histogram TA is divided into 256 unit, element numerals x is integer, and 0��x��255, and the cell height H (x) of temperature rectangular histogram x unit is equal to the pixel number met the following conditions:

$x=\frac{A(i,j)-\min T}{\max T-\min T}*255;$

Further, in step S523, first it is temperature values different in statistics infrared temperature image A, and the pixel number that each temperature value is corresponding;

Then, it is that different temperature values is represented with corresponding element numerals x:

$x=\frac{A(i,j)-\min }{\max T-\min T}*255,0\≤x\≤255;$

The pixel number that each temperature value is corresponding is the pixel number that corresponding units label is corresponding, namely the cell height H (x) described in step S523.

S524. temperature rectangular histogram transverse axis is divided into low temperate zone, room temperature band and thermal zone, asks for the critical point lowx of low temperate zone and room temperature band, ask for room temperature band and thermal zone critical point highx.

Described step S53 includes: seek the gray value that in image A, each pixel is corresponding, obtain infrared hybrid optical system GA: pixel (i, j) corresponding gray value GA (i, j), equal to pixel (i, j) temperature value A (i, j) element numerals corresponding in temperature rectangular histogram.

Described step S54 includes: according to each pixel in image GA (i, pixel value GA j) (and i, j) and the relation of lowx, highx, try to achieve correspondence grey level compensation value GAS (i, j), obtains grey level compensation image GAS:

(1) if GA (i, j) less than lowx, GAS, (i, j) takes 0;

(2) if GA (i, j) more than highx, GAS, (i, j) takes 255;

(3) if GA (i, j) between lowx and highx:

$GAS(i,j)=\frac{GA(i,j)-lowx}{highx-lowx}*255$

Described step S55 includes following sub-step:

S551. grey level compensation compression of images is become jpeg image, and preserves the temperature value array that gray value in grey level compensation image is corresponding;

S552. use acquiescence rectangle frame that jpeg image is carried out labelling in jpeg image;

S553. the upper left lower right coordinate of acquiescence rectangle frame, acquiescence rectangle frame maximum temperature point temperature value and acquiescence rectangle frame maximum temperature point coordinates are preserved;

S554. the temperature value array that the jpeg image of present frame is corresponding with acquiescence rectangle frame upper left lower right coordinate, acquiescence rectangle frame maximum temperature point temperature value, acquiescence rectangle frame maximum temperature point coordinates and infrared gray scale forms the compression picture frame of present frame.

Further, grey level compensation compression of images becomes in the process of jpeg image, the height of image and width do not change, corresponding pixel coordinate system is also without changing, and acquiescence rectangle frame upper left lower right coordinate, acquiescence rectangle frame maximum temperature point temperature value and acquiescence rectangle frame maximum temperature point coordinates are all based on the pixel coordinate system in grey level compensation image.

Further, give tacit consent to rectangle frame, refer to artificial setting acquiescence rectangle marked region, carry out labelling by a part of specific region of gained jpeg image according to being manually set.

As in figure 2 it is shown, a kind of IR Image Compression suitable in contact net, including data acquisition module and data processing module; Described data processing module includes infrared video compressed file creating unit, index file creation unit, compression processing unit and frame information and generates unit:

Described data acquisition module for obtaining infrared temperature image stream from infrared camera;

Described infrared video compressed file creating unit is for creating the infrared video compressed file of blank;

Described index file creation unit is for creating the index file of blank;

Described compression processing unit, for each frame infrared temperature image in infrared temperature image stream is processed, obtains the compression picture frame of present frame infrared temperature image, and writes in video compress file by compression picture frame with additional pattern;

Described frame information generates unit for the compression picture frame delta frame information for present frame infrared temperature image, and is write in index file with additional pattern by the frame information generated.

Substantially, contact net is in the process carrying out infrared image acquisition, also tend to be synchronously performed the collection of high-definition image, owing to infrared camera is likely to different with the physical characteristic frame per second of high definition camera, the frame number of shooting per second is likely to difference, in subsequent processes, usually require to look up infrared image and the high-definition image of synchronization, at this moment, frame number according to infrared image finds its timestamp, at the high-definition image finding synchronization according to this timestamp, thus realizing synchronization infrared, high-definition image.

Claims (8)

1. the IR image compression method being applicable to contact net, it is characterised in that: comprise the following steps:

S1. from infrared camera, obtain infrared temperature image stream;

S2. each frame infrared temperature image in infrared temperature image stream is taken out successively according to the time order and function order of infrared camera shooting;

S3. judge that whether present frame infrared temperature image is the first two field picture of infrared temperature image stream:

(1) if present frame infrared temperature image is the first two field picture of infrared temperature image stream, step S4 is jumped to;

(2) if present frame infrared temperature image is not the first two field picture of infrared temperature image stream, step S5 is jumped to;

S4. create the infrared video compressed file of blank and the index file that correspondence is blank, and indexed file writes file header;

S5. it is compressed present frame infrared temperature image processing, obtains the compression picture frame of present frame, and compression picture frame is write in infrared video compressed file with additional pattern; It is the frame information of the compression picture frame generation correspondence of present frame simultaneously, and the frame information generated is write in index file with additional pattern;

S6. judge that whether present frame infrared temperature image is the last frame image of infrared temperature image stream:

(1) if present frame infrared temperature image is the last frame image of infrared temperature image stream, this second compression terminates;

(2) if present frame infrared temperature image is the last frame image of infrared temperature image stream, jump to step S3, next frame infrared temperature image is carried out the operation of step S3��S6.

2. a kind of IR image compression method suitable in contact net according to claim 1, it is characterised in that: described step S4 includes following sub-step:

S41. the infrared video compressed file of blank and the index file that correspondence is blank are created;

S42. writing file header in indexed file, the file header of write includes picture traverse information and the picture altitude information of infrared video compressed file.

3. a kind of IR image compression method suitable in contact net according to claim 1, it is characterised in that: described step S5 includes following sub-step:

S51. the infrared temperature data of present frame infrared temperature image are obtained;

S52. to present frame infrared temperature image statistics temperature data and generate temperature rectangular histogram;

S53. present frame infrared temperature image is converted to infrared hybrid optical system;

S54. infrared hybrid optical system is carried out high temperature and low temp compensating, then promotes room temperature band contrast, obtain grey level compensation image;

S55. form the compression picture frame of present frame infrared temperature image, compression picture frame is write in infrared video compressed file with additional pattern;

S56. it is the frame information of the compression picture frame generation correspondence of present frame, and the frame information generated is write in index file with additional pattern.

4. a kind of IR image compression method suitable in contact net according to claim 3, it is characterised in that: described step S52 includes following sub-step:

S521. the statistics pixel sum n of present frame infrared temperature image, maximum temperature maxT, minimum temperature minT, high temperature dot number highc and low temperature are counted out lowc;

S522. definition present frame infrared temperature image is image A, if the height of image A is h, the width of image A is w, using the upper left corner of image A as initial point, set up pixel coordinate system, the row-coordinate i of pixel coordinate system increases from top to bottom successively, and the row coordinate j of pixel coordinate system increases from left to right successively, defines A (i, j) for pixel (i, j) temperature value at place, wherein 0��i��h-1,0��j��w-1;

S523. creating temperature rectangular histogram TA, and the transverse axis of temperature rectangular histogram TA is divided into 256 unit, element numerals x is integer, and 0��x��255, and the cell height H (x) of temperature rectangular histogram x unit is equal to the pixel number met the following conditions:

$x=\frac{A(i,j)-\min T}{\max T-\min T}*255;$

S524. temperature rectangular histogram transverse axis is divided into low temperate zone, room temperature band and thermal zone, asks for the critical point lowx of low temperate zone and room temperature band, ask for room temperature band and thermal zone critical point highx.

5. a kind of IR image compression method suitable in contact net according to claim 3, it is characterized in that: described step S53 includes: seek the gray value that in image A, each pixel is corresponding, obtain infrared hybrid optical system GA: pixel (i, j) corresponding gray value GA (i, j), equal to pixel (i, temperature value A (i, j) element numerals corresponding in temperature rectangular histogram j).

6. a kind of IR image compression method suitable in contact net according to claim 3, it is characterized in that: described step S54 includes: according to each pixel (i in image GA, j) pixel value GA (i, and lowx j), the relation of highx, try to achieve correspondence grey level compensation value GAS (i, j), obtains grey level compensation image GAS:

(1) if GA (i, j) less than lowx, GAS, (i, j) takes 0;

(2) if GA (i, j) more than highx, GAS, (i, j) takes 255;

(3) if GA (i, j) between lowx and highx:

$GAS(i,j)=\frac{GA(i,j)-lowx}{highx-lowx}*255.$

7. a kind of IR image compression method suitable in contact net according to claim 3, it is characterised in that: described step S55 includes following sub-step:

S551. grey level compensation compression of images is become jpeg image, and preserves the temperature value array that gray value in grey level compensation image is corresponding;

S552. use acquiescence rectangle frame that jpeg image is carried out labelling in jpeg image;

S553. the upper left lower right coordinate of acquiescence rectangle frame, acquiescence rectangle frame maximum temperature point temperature value and acquiescence rectangle frame maximum temperature point coordinates are preserved;

S554. the temperature value array that the jpeg image of present frame is corresponding with acquiescence rectangle frame upper left lower right coordinate, acquiescence rectangle frame maximum temperature point temperature value, acquiescence rectangle frame maximum temperature point coordinates and infrared gray scale forms the compression picture frame of present frame.

8. the IR Image Compression being applicable to contact net, it is characterised in that: include data acquisition module and data processing module; Described data processing module includes infrared video compressed file creating unit, index file creation unit, compression processing unit and frame information and generates unit:

Described data acquisition module for obtaining infrared temperature image stream from infrared camera;

Described infrared video compressed file creating unit is for creating the infrared video compressed file of blank;

Described index file creation unit is for creating the index file of blank;

Described compression processing unit, for each frame infrared temperature image in infrared temperature image stream is processed, obtains the compression picture frame of present frame infrared temperature image, and writes in video compress file by compression picture frame with additional pattern;

Described frame information generates unit for the compression picture frame delta frame information for present frame infrared temperature image, and is write in index file with additional pattern by the frame information generated.