CN105466563B - A kind of heteropical module and method of two point correction thermal infrared imager - Google Patents
A kind of heteropical module and method of two point correction thermal infrared imager Download PDFInfo
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- CN105466563B CN105466563B CN201410456948.8A CN201410456948A CN105466563B CN 105466563 B CN105466563 B CN 105466563B CN 201410456948 A CN201410456948 A CN 201410456948A CN 105466563 B CN105466563 B CN 105466563B
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Abstract
The invention discloses a kind of heteropical module of two point correction thermal infrared imager and methods, low temperature black matrix image and high temperature blackbody image are acquired first with detector, weighted mean operation is carried out after heteropical module of two point correction thermal infrared imager receives, operation result is stored in serial FLASH, completes calibration；Timing first reads scalable video from serial FLASH and is stored in external memory, calculates correction parameter in real time after valid data arrival, while indicating and going bad first position out, completes correction and bad pixel replacement.The present invention introduces the average weighted method of multiframe in calibration, improves the accuracy of calibration；External memory arbitration control is introduced, calibration, correction and FLASH operation are combined, algorithm high modularization improves portability；The bad member of positioning, completes bad pixel replacement while correction.
Description
Technical field
The invention belongs to the Nonuniformity Correction field of infra-red thermal imaging system, especially a kind of two point correction infrared thermal imagery
The heteropical module and method of instrument.
Background technique
In the past few decades, first number of infrared detector is continuously increased, and is developed to alignment by unit, is sent out by alignment
Open up focal plane arrays (FPA) (FPA).The appearance of infrared focal plane array seeker is an epoch-making leather in infrared imaging history
Life, the sensitivity and reliability of infrared imaging system greatly improved in it.Pass as modern infrared system and thermal imaging system
Key member, gazing type infrared focal plane array (IRFPA) device cost is cheap, small in size, without refrigeration, at present in military affairs
(infrared track, early warning, guidance), medical treatment, safety etc. are used widely, and the infrared imaging system constituted with it is more traditional
Optical mechaical scanning infrared imaging system have structure simple, the operation is stable, high sensitivity, noise equivalent temperature difference (NETD) small etc. excellent
Point.
However, influenced by infrared detector material and process aspect, the non-uniformity of infrared focal plane array at
For the root problem for restricting its application for a long time.Heterogeneity in general sense refers to infrared focal plane array same equal
Cause its video output amplitude different since the infrared response degree of each pixel of detector is inconsistent under even radiation, image quality is caused to drop
It is low, also known as spatial noise；Heterogeneity in further meaning further include by focal plane arrays (FPA) local environment temperature change,
The factors such as charge transfer efficiency, 1/f noise (current noise), ineffective detection member (bad member) and infrared optical system are made
At image quality decline.The picture noise of this fixation declines the temperature resolution of infrared imaging system, picture quality
It is severely impacted.Therefore, it is necessary to carry out Nonuniformity Correction to infrared focal plane array.
Generalling use later period algorithm process carrys out compensation space heterogeneity at present.It in general, can be by these technologies point
For two major class, the i.e. Nonuniformity Correction based on calibration and based on scene.It originally develops and uses based on the non-of calibration
Homogeneity correction technology, wherein more mature method be based on detection member single-point, two o'clock and multiple spot scaling algorithm, they with
Based on Planck's law of radiation and the linear response model of infrared acquisition member, it is widely used among imaging system at this stage.
In recent years, the various Nonuniformity Corrections based on scene also continue to bring out, and to make up temperature drift phenomenon, avoid calibration process；
But extreme scenes are being faced, when switching repeatedly such as scene stillness, rotation of lens or the great scene of contrast, calibration result can be substantially
It degenerates, or even can not observe；In addition, being limited to existing system structure and level of hardware, it is only used for software emulation or subsequent
Processing can not also accomplish that practical application is still immature in real time.Comparatively, the Nonuniformity Correction based on calibration is more accurate,
There is no particular/special requirement for scene and target, hardware is easily achieved and integrates, and is the generally acknowledged assessment of infrared focal plane array system
Means.
To obtain higher frame frequency and better image quality, the detector and external memory devices of thermal infrared imager are not
Disconnected to update, each system architecture upgrading must all rewrite the processing routine of two point correction, carry out a large amount of repeatability
Work, extends the development cycle.
Summary of the invention
The purpose of the present invention is to provide a kind of heteropical module of two point correction thermal infrared imager and method, in conjunction with
The system architecture of FPGA+ external memory makes thermal imaging system meet wanting for online calibration and real time correction in actual use
It asks.
The technical solution for realizing the aim of the invention is as follows: a kind of heteropical mould of two point correction thermal infrared imager
Block, including data format adjustment module, serial ports command analysis module, calibration control module, weighted mean operation module, outside are deposited
Reservoir arbitrates control module, the first fifo buffer, the second fifo buffer, module of averaging and turns string and FLASH control
Device, internal register, two o'clock parameter calculating module, two point correction module and bad pixel replacement module.
Weighted mean operation module is controlled with serial ports command analysis module, calibration control module and external memory arbitration respectively
Molding block connection, external memory arbitrate control module respectively with serial ports command analysis module, calibration control module, the 2nd FIFO
Buffer area, module of averaging are connected with two o'clock parameter calculating module, calibration control module respectively with data format adjust module and
The connection of serial ports command analysis module, two point correction module are joined with serial ports command analysis module, the first fifo buffer, two o'clock respectively
Number computing module is connected with bad pixel replacement module, and turn string and FLASH controller are connect with the second fifo buffer, data format
Adjustment module is connect with the first fifo buffer, and two o'clock parameter calculating module is connect with bad pixel replacement module, and external memory is secondary
Control module external external memory again is cut out, external memory arbitrates control module, module of averaging and turns string and FLASH control
Device and internal register processed distinguish external serial FLASH.
Data format adjusts module and the initial data that the detector of thermal infrared imager acquires is converted into standard data,
That is present frame A, and it is sent to calibration control module and the first fifo buffer；Detector alignment low temperature thermal infrared imager is black
Body, serial ports command analysis module parse the focus command of host computer, and obtained cumulative frame number p and deposit low temperature and enable
It is sent into calibration control module, weighting parameter q is sent into weighted mean operation module；Calibration control module control present frame A, which is sent to, to be added
Weight average computing module is weighted and averaged operation, sends read write command to external memory and arbitrates control module, deposits in outside
Storage frame B is read in reservoir and mean value frame C is written, after loop iteration p times, final mean value frame C low temperature scalable video L.
External memory arbitrates control module and receives each read write command, is arranged in time them, sends read-write
Request, address and data control external memory and circuit sequentially each read write command of response to external memory；Again infrared thermal imagery
The detector of instrument is directed at high temperature blackbody, repeats the above process, obtains high temperature scalable video H；The transmission of serial ports command analysis module is write
FLASH enable signal arbitrates control module to external memory, and low temperature scalable video L and height are read simultaneously from external memory
Warm scalable video H is respectively fed to average module and the second fifo buffer；Module of averaging finds out low temperature scalable video respectively
The mean value of LWith the mean value of high temperature scalable video HAnd they are stored in the user area of serial FLASH；Second fifo buffer
For realizing rate-matched, the data after buffering are sent into and turn string and FLASH controller；And turn string and FLASH controller completion
Low temperature scalable video L and high temperature scalable video H are converted into serial data, are successively sequentially written in string by the configuration to serial FLASH
The user area row FLASH, so far scale operation is completed.
After system re-powers, low temperature scalable video L and high temperature scalable video H are sequential read out from serial FLASH automatically
And give to external memory and arbitrate control module, external memory designated position is written by it；Serial FLASH reads low temperature automatically
The mean value of scalable videoWith the mean value of high temperature scalable videoIt is stored in internal register；When a frame normal data reaches first
When fifo buffer, control module is just arbitrated by external memory and reads simultaneously low temperature scalable video L and high temperature scalable video
H reads the mean value of low temperature scalable video from internal registerWith the mean value of high temperature scalable videoIt is sent to two o'clock parameter together
Gain correction coefficient K and bias correction coefficient B 1 is calculated by two o'clock parameter calculating module in computing module, and by gain school
Positive coefficient K and bias correction coefficient B 1 are sent into two point correction module and are corrected, the image Y after being corrected, if gain calibration
The value of COEFFICIENT K and bias correction coefficient B 1 is more than the threshold value of setting, is just 1 bad first mark position, is otherwise set to 0, bad member mark
Bad pixel replacement module is sent into will position；Image Y after correction is re-fed into bad pixel replacement module, the bad member mark of bad pixel replacement module detection
Just one before pixel value corresponding at this caching pixel value is replaced, so far at correction once being found to be 1 will position
Reason is completed, and obtained final image is exported.
First fifo buffer plays the synchronous effect of data, normal data, gain correction coefficient K and bias correction system
Number B1 alignment, is sent into two point correction module together.
The weighted mean operation formula of above-mentioned weighted mean operation module are as follows:
Wherein C is mean value frame, i.e. the frame image that is averaged of single.
The two o'clock parameter calculation formula of two o'clock parameter calculating module are as follows:
The two point correction formula of two point correction module are as follows:
Y=KX+B1
X represents the normal data of data format adjustment module output.
A kind of heteropical method of two point correction thermal infrared imager, steps are as follows:
Step 1) is calibrated online, obtains low temperature scalable video L and high temperature scalable video H:
Step 1-1) data format adjustment module receives the real-time Infrared video sequence that thermal infrared imager obtains, i.e. present frame
The detector of thermal infrared imager is directed at low temperature black matrix by A, and using serial port setting weighting parameter q and cumulative frame number p, p range is 0,
1,2,3 ... 1024, q range be 0,1,2,3 ... 1024, and provide storage low temperature image enable signal, serial ports instruction parsing mould
After block receives the low temperature image enable signal, deposited by calibration control module control external memory arbitration control module in outside
It is stored in piece image in reservoir, i.e. storage frame B, then storage frame B is read from external memory, in weighted mean operation module
Each pixel collection value of present frame A and storage frame B corresponding position are weighted and averaged, formula are as follows:
Wherein C is mean value frame, i.e., the frame image that single is averaged covers the corresponding position of C deposit storage frame B
The value of B is covered as new storage frame, repeats above-mentioned weighted mean procedure p times, obtains low temperature scalable video L.
Step 1-2) the detector alignment high temperature blackbody of thermal infrared imager is provided using serial ports and deposited referring to step 1-1)
Store up the enable signal of high temperature image, the high temperature scalable video H after being weighted and averaged.
FLASH enable signal is write in the sending of step 2) serial ports command analysis module, arbitrates control module control by external memory
External memory processed reads simultaneously low temperature scalable video L and high temperature scalable video H, and adds up and be averaged in module of averaging
Respectively obtain the response mean value of low temperature scalable video LWith the response mean value of high temperature scalable video HThrough and turn string and FLASH control
The user area of serial FLASH is stored in after device parallel-serial conversion processed；80 degree of high temperature blackbody and 0 degree of low temperature black matrix are selected, is being controlled
The calibration process that step 1) is completed under signal function processed, by the low temperature scalable video L ' of reading and high temperature scalable video H ', and
Low temperature responds mean valueWith high-temperature response mean valueIt is stored in the factory region of serial FLASH together.
After the completion of the above-mentioned calibration process of step 3), real-time correct operation is carried out:
After each system electrification is stablized, L and H is read from the user area of serial FLASH automatically, is stored in external memory
Specified region, read response mean valueWithIt is stored in internal register, if you need to factory reset, then from the factory of serial FLASH
Region reads L ' and H ' deposit external memory, readsWithIt is stored in internal register.
Step 4) valid data arrive after, read simultaneously L, H obtained in step 3),WithMould is calculated in two o'clock parameter
Two point correction parameter, specific formula are determined in block are as follows:
Wherein, K indicates that the gain correction coefficient of two point correction, B1 indicate the bias correction coefficient of two point correction.
Finally usage factor K and B1 in two point correction module complete to correct the two point correction of image step 5)
Image Y afterwards, the formula of two point correction are as follows:
Y=KX+B1
Wherein, X represents the normal data of data format adjustment module output, and Y represents the image after correction.
Image Y after correction is re-fed into bad pixel replacement module by step 6), and bad pixel replacement module, which detects, goes bad first flag bit, and one
Denier is found to be 1, and just one before pixel value corresponding at this caching pixel value is replaced, and so far correction process is completed,
Obtained final image is exported.
Above-mentioned steps 4) in, if a great K or B1 value occurs in a certain pixel, the threshold value of setting is had exceeded, then is said
Bright H-L at this levels off to 0, i.e. high temperature and Low Temperature Target responds abnormal in the point, be judged as bad member, detects all
It will first mark position be badly 1 on such position, it is other to be set to 0 under normal circumstances.
Above-mentioned steps 1-4) in, the operation of all pairs of external memories is managed by external memory arbitration control module is unified
Reason, algorithm arbitrate control module application to external memory, circuit sequentially each application of response using the thought of time-sharing multiplex.
Step 1-1) and step 1-2) sequentially exchange.
Step 2) high temperature black matrix and low temperature black matrix, wherein low temperature blackbody temperature is 20 degree and high temperature blackbody temperature is 60
Degree.
Compared with prior art, the present invention its remarkable advantage: (1) the average weighted method of multiframe in calibration process is introduced,
Cumulative frame number can be adjusted to 1024 from 1, to reduce the interference of random noise bring, improve the accuracy for entering parameter in FLASH；
(2) hardware high modularization, inner parameter and control signal are by exterior arrangement, portable good, calibration, correction and FLASH
Operation all combines, easy to operate, is conducive to maintenance, adapts to different frame frequencies and data format, versatile；(3) at
Reason process all uses hardware realization, and speed is fast, meets requirement of real-time, and bad pixel replacement is completed while two point correction, simplifies
Processing step.
Detailed description of the invention
Fig. 1 is a kind of heteropical module of two point correction thermal infrared imager of the present invention and the process flow diagram of method.
Fig. 2 is the two point correction effect picture of the infrared video sequence of real scene, wherein figure (a) is adopting without bad member detection
With the correction image of single frames high/low temperature image calibration, scheming (b) is the average weighted high/low temperature figure of use multiframe containing bad member detection
As the correction image of calibration.
Specific embodiment
Present invention is further described in detail with reference to the accompanying drawing.
The present invention is the heteropical module and method of a kind of two point correction thermal infrared imager.Its principle are as follows: sharp first
Low temperature black matrix image is acquired with detector and high temperature blackbody image, heteropical module through two point correction thermal infrared imager connect
Weighted mean operation is carried out after receipts, operation result is stored in serial FLASH, completes calibration；Timing is first read from serial FLASH
Scalable video is stored in external memory, calculates correction parameter in real time after valid data arrival, while indicating and going bad first position out, complete
At correction and bad pixel replacement.
In conjunction with Fig. 1, a kind of heteropical module of two point correction thermal infrared imager, it is characterised in that: including data lattice
Formula adjusts module, serial ports command analysis module, calibration control module, weighted mean operation module, external memory arbitration control
Module, the first fifo buffer, the second fifo buffer, module of averaging and turn string and FLASH controller, internal register,
Two o'clock parameter calculating module, two point correction module and bad pixel replacement module.
Weighted mean operation module is controlled with serial ports command analysis module, calibration control module and external memory arbitration respectively
Molding block connection, external memory arbitrate control module respectively with serial ports command analysis module, calibration control module, the 2nd FIFO
Buffer area, module of averaging are connected with two o'clock parameter calculating module, calibration control module respectively with data format adjust module and
The connection of serial ports command analysis module, two point correction module are joined with serial ports command analysis module, the first fifo buffer, two o'clock respectively
Number computing module is connected with bad pixel replacement module, and turn string and FLASH controller are connect with the second fifo buffer, data format
Adjustment module is connect with the first fifo buffer, and two o'clock parameter calculating module is connect with bad pixel replacement module, and external memory is secondary
Control module external external memory again is cut out, external memory arbitrates control module, module of averaging and turns string and FLASH control
Device and internal register processed distinguish external serial FLASH.
Data format adjusts module and the initial data that the detector of thermal infrared imager acquires is converted into standard data,
That is present frame A, and it is sent to calibration control module and the first fifo buffer；Detector alignment low temperature thermal infrared imager is black
Body, serial ports command analysis module parse the focus command of host computer, and obtained cumulative frame number p and deposit low temperature and enable
It is sent into calibration control module, weighting parameter q is sent into weighted mean operation module；Calibration control module control present frame A, which is sent to, to be added
Weight average computing module is weighted and averaged operation, sends read write command to external memory and arbitrates control module, deposits in outside
Storage frame B is read in reservoir and mean value frame C is written, after loop iteration p times, final mean value frame C low temperature scalable video L.
External memory arbitrates control module and receives each read write command, is arranged in time them, sends read-write
Request, address and data control external memory and circuit sequentially each read write command of response to external memory；Again infrared thermal imagery
The detector of instrument is directed at high temperature blackbody, repeats the above process, obtains high temperature scalable video H；The transmission of serial ports command analysis module is write
FLASH enable signal arbitrates control module to external memory, and low temperature scalable video L and height are read simultaneously from external memory
Warm scalable video H is respectively fed to average module and the second fifo buffer；Module of averaging finds out low temperature scalable video respectively
The mean value of LWith the mean value of high temperature scalable video HAnd they are stored in the user area of serial FLASH；Second fifo buffer
For realizing rate-matched, the data after buffering are sent into and turn string and FLASH controller；And turn string and FLASH controller completion
Low temperature scalable video L and high temperature scalable video H are converted into serial data, are successively sequentially written in string by the configuration to serial FLASH
The user area row FLASH, so far scale operation is completed.
After system re-powers, low temperature scalable video L and high temperature scalable video H are sequential read out from serial FLASH automatically
And give to external memory and arbitrate control module, external memory designated position is written by it；Serial FLASH reads low temperature automatically
The mean value of scalable videoWith the mean value of high temperature scalable videoIt is stored in internal register；When a frame normal data reaches first
When fifo buffer, control module is just arbitrated by external memory and reads simultaneously low temperature scalable video L and high temperature scalable video
H reads the mean value of low temperature scalable video from internal registerWith the mean value of high temperature scalable videoIt is sent to two o'clock parameter together
Gain correction coefficient K and bias correction coefficient B 1 is calculated by two o'clock parameter calculating module in computing module, and by gain school
Positive coefficient K and bias correction coefficient B 1 are sent into two point correction module and are corrected, the image Y after being corrected, if gain calibration
The value of COEFFICIENT K and bias correction coefficient B 1 is more than the threshold value of setting, is just 1 bad first mark position, is otherwise set to 0, bad member mark
Bad pixel replacement module is sent into will position；Image Y after correction is re-fed into bad pixel replacement module, the bad member mark of bad pixel replacement module detection
Just one before pixel value corresponding at this caching pixel value is replaced, so far at correction once being found to be 1 will position
Reason is completed, and obtained final image is exported；
First fifo buffer plays the synchronous effect of data, normal data, gain correction coefficient K and bias correction system
Number B1 alignment, is sent into two point correction module together.
A kind of heteropical method of two point correction thermal infrared imager, method and step are as follows:
When infrared detector acquires video sequence, since each pixel of detector has inconsistent sound to identical radiation irradiation
It answers, so that being superimposed one layer of fixed pattern noise, i.e. heterogeneity on display image, this can seriously affect picture quality.According to
Irradiation level-voltage model of detector pixel, it is approximately linear for detector being responded, i.e. y (i, j)=g (i, j) x (i,
J)+o (i, j), the difference of g (i, j) and o (i, j) may be considered the root of heterogeneity generation between each pixel point.In order to disappear
Except this influence, two points that can be obtained according to high/low temperature image mean value determine one with reference to straight line, by each pixel
The g (i, j) and o (i, j) of point are corrected, they are all corrected on reference curve, so that output image uniform.Hardware realization
Final purpose be exactly the gain correction coefficient w found out at each pixel point of detectorn(i, j) and bias correction coefficient bn(i,
J), by wn(i, j) and bnThe gain correction coefficient matrix w (i, j) and b (i, j) that (i, j) is constituted are stored in external memory, whenever
Valid data just read corresponding position coefficient when arriving is corrected, compensation heterogeneity bring interference.
Updating formula are as follows: x (i, j)=w (i, j) y (i, j)+b (i, j), wherein gain coefficient correction matrix w (i, j) and
Biasing coefficient correction matrix b (i, j) is respectively
Hardware realization mainly includes two parts of calibration and correction, the exterior arrangement coefficient used in the process, enable signal
It is sent by host computer by serial ports.
Thermal infrared imager collects the initial data of real-time Infrared video sequence, is first fed into internal data format adjustment
Module, ranks number and valid data location information needed for adjusting module configuration for data format, can integrate initial data
For the format of normal data, as present frame A, be used for subsequent calibration and correction, the format of normal data be to connect before every frame
Continuous valid data, followed by being consecutive invalid data.
It is calibrated online followed by high/low temperature scene.The detector of thermal infrared imager is directed at low temperature black matrix, to infrared
Detector the operation is stable of thermal imaging system after blackbody temperature is uniform, starts to acquire low temperature image.Utilize serial port setting weighting parameter q
With cumulative frame number p, p range is 0,1,2,3 ..., and 1024, q ranges are 0,1,2,3 ... 1024, and provide making for storage low temperature image
Energy signal after serial ports command analysis module receives the low temperature image enable signal, controls external storage by calibration control module
Device arbitration control module is stored in piece image in external memory, i.e. storage frame B, then reads storage frame from external memory
B, in weighted mean operation module by present frame A and storage frame B corresponding position each pixel collection value be weighted it is flat
, formula are as follows:
Wherein C is mean value frame, i.e., the frame image that single is averaged covers the corresponding position of C deposit storage frame B
The value of B is covered as new storage frame, repeats above-mentioned weighted mean procedure p times, obtains low temperature scalable video L.Weighting parameter q and tired
Add frame number p act synergistically, the value of the weighting parameter q of setting is smaller, influence of the present frame A to low temperature scalable video L with regard to smaller, with
Cooperation cumulative frame number p value it is then bigger, it is also stronger to the inhibiting effect of system random noise in this way；The weighting parameter of setting
The value of q is bigger, and influence of the present frame A to low temperature scalable video L is bigger, and the value of matched cumulative frame number p is then smaller, this
Sample calibration accuracy is influenced just to become larger by random noise；As q=1024 or p=1, the case where being calibrated for single frames of degenerating.
The detector of thermal infrared imager is directed at high temperature blackbody, referring to above-mentioned calibration process, it is high to provide storage using serial ports
The enable signal of warm image, the high temperature scalable video H after being weighted and averaged.
FLASH enable signal is write in the sending of serial ports command analysis module, external by external memory arbitration control module control
Memory reads simultaneously low temperature scalable video L and high temperature scalable video H, and adds up to be averaged in module of averaging and obtain respectively
To the response mean value of low temperature scalable video LWith the response mean value of high temperature scalable video HThrough and turn string and FLASH controller simultaneously
The user area of serial FLASH is stored in after string conversion；80 degree of high temperature blackbody and 0 degree of low temperature black matrix are selected respectively, are being controlled
The calibration process that step 1) is completed under signal function, by the low temperature scalable video L ' of reading and high temperature scalable video H ' and low
Temperature response mean valueWith high-temperature response mean valueIt is stored in the factory region of serial FLASH together, so far scale operation is completed.
Followed by real-time correct operation.After each system electrification is stablized, automatically from the user area of serial FLASH
L and H is read, the specified region of external memory, read response mean value are stored inWithIt is stored in internal register, if you need to recover
Factory's setting, then read L ' and H ' deposit external memory from the factory region of serial FLASH, readsWithThe internal deposit of deposit
In device.To valid data arrive, read simultaneously L, H,WithTwo point correction parameter is determined in two o'clock parameter calculating module, it is public
Formula are as follows:
Wherein, K indicates that the gain correction coefficient of two point correction, B1 indicate the bias correction coefficient of two point correction；Specifically answer
Used time, generally between 0.5 to 1.5, the range of bias correction coefficient B 1 is generally arrived -400 the range of gain correction coefficient K
Between 400, to guarantee computational accuracy, molecule is avoided negative occur, needs that the molecule of gain correction coefficient K is first amplified 1024 times,
Bias correction coefficient B 1 is superimposed one 1024 biasing, and formula becomes:
The value of gain correction coefficient K and bias correction coefficient B 1 are detected simultaneously, if a great K occurs in a certain pixel
Or B value, the threshold value of setting is had exceeded, then illustrates that the H-L at this levels off to 0, i.e., high temperature and Low Temperature Target respond not just in the point
Often, it is judged as bad member, will first mark position will be badly 1 on all such positions detected, it is other to be set to 0 under normal circumstances.
It is buffered from the first fifo buffer valid data, gain correction coefficient K and bias correction coefficient B 1, then
It reads simultaneously, makes the aligned in position of three, valid data are corrected with gain correction coefficient K and bias correction coefficient B 1,
Formula are as follows:
Y=KX+B1
Wherein, X represents the normal data of data format adjustment module output, and Y represents the image after correction；Concrete application
When, to restore normal gain correction coefficient K and bias correction coefficient B 1, formula becomes:
Image Y after correction is re-fed into bad pixel replacement module, the bad first flag bit of bad pixel replacement module detection, once it finds
It is 1, just one before pixel value corresponding at this caching pixel value is replaced, so far correction process is completed, and will be obtained
Final image output.
The read-write operation of all pairs of external memories passes through external memory and arbitrates control module in above-mentioned treatment process
Unified management.General external memory read or write speed is very fast, and thermal infrared imager acquisition real-time Infrared video sequence and FLASH
Read or write speed is slower, therefore using the thought of time-sharing multiplex, first distributes for first read-write requests to external memory certain
The domination time, so that its is monopolized external memory resource during this period of time, it is external to be then followed successively by the distribution of other read-write requests
The domination time of memory, rotation handle each read-write requests；It is in this way actually that external memory is divided into time
Multiple portions, then they are distributed to different read-write requests and is used.
Embodiment 1
Detector selects the non-refrigeration type thermal infrared imager of 384 × 288 pixels, and the frame frequency of acquisition is that 50 frames are per second, two o'clock
The heteropical module for correcting thermal infrared imager selects the EP3C40F484I7 chip of ALTERA company, and external memory is selected
SDRAM, model MT48LC16M16A2FG observe real scene with the system.In conjunction with Fig. 2, wherein Fig. 2 (a) is
The correction image using single frames high/low temperature image calibration without bad member detection, Fig. 2 (b) are the use multiframe weighting containing bad member detection
The correction image of average high/low temperature image calibration.As can be seen that there are more vertical line and spots for the image in Fig. 2 (a), still
In the presence of bad member, and the image in Fig. 2 (b) is more smooth, and bad member is substituted.The present invention is realized by high modularization, is applicable in
In the different external memory systems such as SRAM, SDRAM, DDR, it may be convenient to transplant.
Claims (7)
1. a kind of heteropical module of two point correction thermal infrared imager, it is characterised in that: including data format adjustment module,
Serial ports command analysis module, calibration control module, weighted mean operation module, external memory arbitrate control module, first
Fifo buffer, the second fifo buffer, module of averaging simultaneously turn string and FLASH controller, internal register, two o'clock parameter
Computing module, two point correction module and bad pixel replacement module；
Weighted mean operation module controls mould with serial ports command analysis module, calibration control module and external memory arbitration respectively
Block connection, external memory are arbitrated control module and are buffered respectively with serial ports command analysis module, calibration control module, the 2nd FIFO
Area, module of averaging are connected with two o'clock parameter calculating module, and calibration control module adjusts module and serial ports with data format respectively
Command analysis module connection, two point correction module respectively with serial ports command analysis module, the first fifo buffer, two o'clock parameter meter
It calculates module to connect with bad pixel replacement module, and turn string and FLASH controller are connect with the second fifo buffer, data format adjustment
Module is connect with the first fifo buffer, and two o'clock parameter calculating module is connect with bad pixel replacement module, external memory arbitration control
Molding block again arbitrate control module, module of averaging and turn string and FLASH controller by external external memory, external memory
External serial FLASH is distinguished with internal register；
Data format adjusts module and the initial data that the detector of thermal infrared imager acquires is converted into standard data, that is, works as
Previous frame A, and it is sent to calibration control module and the first fifo buffer；The detector of thermal infrared imager is directed at low temperature black matrix, string
Mouth command analysis module parses the focus command of host computer, and obtained cumulative frame number p and deposits the enabled feeding of low temperature
Control module is calibrated, weighting parameter q is sent into weighted mean operation module；It is flat that calibration control module control present frame A is sent to weighting
Equal computing module is weighted and averaged operation, sends read write command to external memory and arbitrates control module, in external memory
Middle reading stores frame B and mean value frame C is written, after loop iteration p times, final mean value frame C low temperature scalable video L；
External memory arbitrates control module and receives each read write command, is arranged in time them, transmission read-write requests,
Address and data control external memory and circuit sequentially each read write command of response to external memory；Again thermal infrared imager
Detector is directed at high temperature blackbody, repeats the above process, obtains high temperature scalable video H；FLASH is write in the transmission of serial ports command analysis module
Enable signal arbitrates control module to external memory, and low temperature scalable video L is read simultaneously from external memory and high temperature is fixed
Logo image H is respectively fed to average module and the second fifo buffer；Module of averaging finds out low temperature scalable video L's respectively
Mean valueWith the mean value of high temperature scalable video HAnd they are stored in the user area of serial FLASH；Second fifo buffer is used
Realize rate-matched, data after buffering are sent into and turn string and FLASH controller；And turn string and FLASH controller completion pair
Low temperature scalable video L and high temperature scalable video H are converted into serial data by the configuration of serial FLASH, are successively sequentially written in serial
The user area FLASH, so far scale operation is completed；
After system re-powers, low temperature scalable video L and high temperature scalable video H are sequential read out from serial FLASH automatically and is sent
Control module is arbitrated to external memory, external memory designated position is written by it；Serial FLASH reads low temperature calibration automatically
The mean value of imageWith the mean value of high temperature scalable videoIt is stored in internal register；When a frame normal data reaches the first FIFO
When buffer area, control module is just arbitrated by external memory and reads simultaneously low temperature scalable video L and high temperature scalable video H, from
The mean value of low temperature scalable video is read in internal registerWith the mean value of high temperature scalable videoIt is sent to the calculating of two o'clock parameter together
Gain correction coefficient K and bias correction coefficient B 1 is calculated by two o'clock parameter calculating module in module, and by gain calibration system
Number K and bias correction coefficient B 1 are sent into two point correction module and are corrected, the image Y after being corrected, if gain correction coefficient K
Value with bias correction coefficient B 1 is more than the threshold value of setting, is just 1 bad first mark position, is otherwise set to 0, bad member flag bit is sent
Enter bad pixel replacement module；Image Y after correction is re-fed into bad pixel replacement module, bad pixel replacement module detects bad first flag bit,
Once being found to be 1, just one before pixel value corresponding at this caching pixel value is replaced, so far correction process is complete
At by the output of obtained final image；
First fifo buffer plays the synchronous effect of data, normal data, gain correction coefficient K and bias correction coefficient B 1
Two point correction module is sent into alignment together.
2. heteropical module of two point correction thermal infrared imager according to claim 1, it is characterised in that:
The weighted mean operation formula of above-mentioned weighted mean operation module are as follows:
Wherein C is mean value frame, i.e. the frame image that is averaged of single；
The two o'clock parameter calculation formula of two o'clock parameter calculating module are as follows:
The two point correction formula of two point correction module are as follows:
Y=KX+B1
X represents the normal data of data format adjustment module output.
3. a kind of heteropical method of two point correction thermal infrared imager, which is characterized in that steps are as follows:
Step 1) is calibrated online, obtains low temperature scalable video L and high temperature scalable video H:
Step 1-1) data format adjustment module receive thermal infrared imager obtain real-time Infrared video sequence, i.e. present frame A, will
The detector of thermal infrared imager is directed at low temperature black matrix, and using serial port setting weighting parameter q and cumulative frame number p, p range is 0,1,2,
3 ... 1024, q range are 0,1,2,3 ... 1024, and provide the enable signal of storage low temperature image, and serial ports command analysis module connects
After receiving the low temperature image enable signal, by calibration control module control external memory arbitration control module in external memory
Interior deposit piece image, i.e. storage frame B, then read storage frame B from external memory, will work as in weighted mean operation module
Each pixel collection value of previous frame A and storage frame B corresponding position is weighted and averaged, formula are as follows:
Wherein C is mean value frame, i.e., the corresponding position of C deposit storage frame B is covered B's by the frame image that single is averaged
Value repeats above-mentioned weighted mean procedure p times as new storage frame, obtains low temperature scalable video L；
Step 1-2) by the detector alignment high temperature blackbody of thermal infrared imager, referring to step 1-1), it is high that storage is provided using serial ports
The enable signal of warm image, the high temperature scalable video H after being weighted and averaged；
FLASH enable signal is write in the sending of step 2) serial ports command analysis module, outer by external memory arbitration control module control
Portion's memory reads simultaneously low temperature scalable video L and high temperature scalable video H, and adds up in module of averaging and be averaged difference
Obtain the response mean value of low temperature scalable video LWith the response mean value of high temperature scalable video HThrough and turn string and FLASH controller
The user area of serial FLASH is stored in after parallel-serial conversion；80 degree of high temperature blackbody and 0 degree of low temperature black matrix are selected, is believed in control
Number lower calibration process for completing step 1) of effect, by the low temperature scalable video L ' of reading and high temperature scalable video H ' and low temperature
Respond mean valueWith high-temperature response mean valueIt is stored in the factory region of serial FLASH together；
After the completion of the above-mentioned calibration process of step 3), real-time correct operation is carried out:
After each system electrification is stablized, L and H is read from the user area of serial FLASH automatically, is stored in the specified of external memory
Region, read response mean valueWithIt is stored in internal register, if you need to factory reset, then from the factory region of serial FLASH
L ' and H ' deposit external memory are read, is readWithIt is stored in internal register；
Step 4) valid data arrive after, read simultaneously L, H obtained in step 3),WithIn two o'clock parameter calculating module
Determine two point correction parameter, specific formula are as follows:
Wherein, K indicates that the gain correction coefficient of two point correction, B1 indicate the bias correction coefficient of two point correction；
Finally usage factor K and B1 in two point correction module complete the two point correction to image to step 5), after being corrected
Image Y, the formula of two point correction are as follows:
Y=KX+B1
Wherein, X represents the normal data of data format adjustment module output, and Y represents the image after correction；
Image Y after correction is re-fed into bad pixel replacement module, the bad first flag bit of bad pixel replacement module detection by step 6), once it sends out
Now it is 1, just one before pixel value corresponding at this caching pixel value is replaced, so far correction process is completed, will
The final image output arrived.
4. heteropical method of two point correction thermal infrared imager according to claim 3, it is characterised in that: above-mentioned step
It is rapid 4) in, if a great K or B1 value occurs in a certain pixel, have exceeded the threshold value of setting, then illustrate that H-L at this is approached
In 0, i.e. high temperature and Low Temperature Target responds abnormal in the point, is judged as bad member, will be bad on all such positions detected
First mark position is 1, other to be set to 0 under normal circumstances.
5. heteropical method of two point correction thermal infrared imager according to claim 3, it is characterised in that: above-mentioned step
It is rapid 1)-step 4) in, the operations of all pairs of external memories is by external memory arbitration control module unified management, algorithm
Control module application is arbitrated to external memory, each application of response is circuited sequentially using the thought of time-sharing multiplex.
6. heteropical method of two point correction thermal infrared imager according to claim 3, it is characterised in that: step 1-
1) it is sequentially exchanged with step 1-2).
7. heteropical method of two point correction thermal infrared imager according to claim 3, it is characterised in that: step 2)
High temperature black matrix and low temperature black matrix, wherein low temperature blackbody temperature is 20 degree and high temperature blackbody temperature is 60 degree.
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| CN107036715B (en) * | 2017-03-30 | 2019-06-14 | 智来光电科技（苏州）有限公司 | A kind of infrared image is without baffle Nonuniformity Correction device and its bearing calibration |
| CN112752041A (en) * | 2019-10-31 | 2021-05-04 | 合肥美亚光电技术股份有限公司 | CMOS image sensor correction method, system and image processing equipment |
| CN111988548B (en) * | 2020-08-25 | 2023-05-19 | 中国电子科技集团公司第二十四研究所 | Pixel-level ADC focal plane readout circuit and correction method thereof |
| CN112781724B (en) * | 2020-12-22 | 2022-11-29 | 上海微波技术研究所（中国电子科技集团公司第五十研究所） | Detector non-uniformity real-time correction method, system and medium based on two-point method |
| CN113514155B (en) * | 2021-04-13 | 2023-04-28 | 武汉华中数控股份有限公司 | Non-uniform correction method without shutter |
| CN114295226A (en) * | 2021-12-29 | 2022-04-08 | 天津大学 | Calibration method for improving thermal imager temperature measurement resolution ratio based on frame accumulation |
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