CN113674134A - Real-time reliable star point identification and storage method - Google Patents
Real-time reliable star point identification and storage method Download PDFInfo
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- CN113674134A CN113674134A CN202110886273.0A CN202110886273A CN113674134A CN 113674134 A CN113674134 A CN 113674134A CN 202110886273 A CN202110886273 A CN 202110886273A CN 113674134 A CN113674134 A CN 113674134A
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Abstract
A real-time reliable star point identification and storage method adopts two FSM state machines, and comprises the following steps: for FSM state machine 1, state 100: circularly obtaining image frames until the number of data in the FIFO of the gray value accumulation sum is greater than 0, and transferring to a state 101; state 101: after the read data is latched, alternately starting a divider 1 and a divider 2; for FSM state machine 2: judging when the operation of the divider 1 or the divider 2 is finished; if the current star point is not the last star point of the image frame and is a pseudo star, the star point transmission has no action; if the current star point is not the last star point of the image frame and is a normal star, latching read data; if the current star point is the last star point of the image frame and is a pseudo star, the star point transmission has no action; and if the current star point is the last star point of the image frame and is a normal star, latching the read data.
Description
Technical Field
The invention relates to a real-time reliable star point identification and storage method, and belongs to the technical field of image processing.
Background
The high-dynamic high-precision star sensor is used for measuring the three-axis attitude of a satellite in an inertial space, provides support for the operation of the satellite in the space through an autonomous acquisition function, and is a key optical attitude measurement component for realizing a satellite control subsystem. And the FPGA is adopted to complete the functions of receiving and preprocessing images of the CCD camera, downloading the images and the like. In the capturing stage, the whole image needs to be subjected to global processing, the speed is low, in the tracking stage after capturing, in order to improve the refresh rate of star point tracking processing, neighborhood windowing processing is carried out, invalid calculation of image data of an out-of-window redundant area is reduced, and the data refresh rate is improved.
In the image processing process, two types of CCD image data are received by the FPGA: and carrying out subsequent image processing on the full image in the capturing mode and the window image in the tracking mode according to whether the working mode is the capturing mode or the tracking mode.
In a capture mode, an FPGA on a DPU receives a full-frame image, filters the full-frame image and extracts effective pixels, then full-frame star point extraction is completed, coordinate information is obtained and stored in an SRAM in the FPGA, and meanwhile sampling is performed, histogram statistics is performed, and the coordinate information is stored in the SRAM in the FPGA.
In a tracking mode, received window image data are stored in an SRAM (static random access memory) in the FPGA, a window image processing module is triggered immediately after window image acquisition is finished, window image processing comprises background threshold calculation, star point extraction, pseudo star judgment, centroid calculation and the like, and the centroid of each window is stored in a star point information SRAM according to a specified format after the centroid calculation is finished.
The process of tracking and processing the window image data comprises star point extraction, pseudo star judgment, centroid calculation and the like, and aims to guarantee the accuracy of a star point capturing stage. The process of capturing and processing the full-width image data in the star point capturing stage comprises star point extraction, pseudo star judgment, star point storage and the like, and the following three problems can be involved in the pseudo star judgment and star point storage process.
Firstly, in the process of performing pseudo star determination for a plurality of continuously captured star points, the following problems occur: the working period of the divider is T1, the interval between two adjacent star points is T2, when the distance between the two adjacent star points is short and the operation time T1 of the divider is greater than the interval T2 between the two adjacent star points, the divider is occupied by the first star point during the operation period, and the state machine is not quitted, so that the calculation result of the second adjacent star point cannot be stored, and the star point is lost. Similarly, as long as the arrival time of the subsequent star point is smaller than the working period T1 of the divider compared with the first star point, the divider is in an occupied state, and the star point data calculation processing cannot be performed, so that the star point is lost.
Secondly, in order to ensure the real-time performance of star point identification operation, a logic structure which collects image data and calculates and stores simultaneously is adopted in logic implementation, when a transmission mark final _ star of the last star point arrives, star point transmission is finished, but the calculation and storage operation of the last star point is not finished, and at the moment, a state machine is interrupted, so that the calculation result of the last star point is lost.
Thirdly, in the operation process, through calculation and judgment, identification marks star _ flag are established for effective star points and pseudo stars in the transmission image, and when the star _ flag is '1', the star is represented as a normal star; at '0', it is represented as a pseudo star. When the star points are stored, if the star points are effective star points, a storage mark tick signal is generated; if the signal is a pseudo star, no store tick signal is generated. And ensuring that the stored result is only valid star points and rejecting pseudo stars at the same time. However, in the actual calculation process, when the last star point is a pseudo star, the state machine cannot detect that the store signal is valid, which may cause an abnormal situation that the state machine cannot exit.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the method adopts the flow process of alternately using two dividers to perform division calculation on star point data in FIFO. The method uses two FSM state machines to carry out logic realization, and comprises the following steps:
for FSM state machine 1:
state 100: circularly obtaining image frames until the number of data in the FIFO of the gray value accumulation sum is greater than 0, and transferring to a state 101;
state 101: after the read data is latched, alternately starting a divider 1 and a divider 2; the conditions for alternately starting divider 1 and divider 2 are: after the divider 1 is started, if the timing time is longer than three system clocks and the number of data in FIFO of the gray value accumulation sum of the image frames is larger than 0, the divider 2 is started; after the divider 2 is started, if the operation of the divider 1 is finished and the number of data in the FIFO of the gray value accumulation sum of the image frame is more than 0, the divider 1 is started; setting the last star point mark signal until the image frame is finished, and transferring to the state 100;
for FSM state machine 2: judging when the operation of the divider 1 or the divider 2 is finished; if the current star point is not the last star point of the image frame and is a pseudo star, the star point transmission has no action; if the current star point is not the last star point of the image frame and is a normal star, latching read data; if the current star point is the last star point of the image frame and is a pseudo star, the star point transmission has no action, and the star point number, the exposure time, the image SYNC star time, the image synchronization signal count, the image clock count and the background estimation value are stored in a star map SRAM; and if the current star point is the last star point of the image frame and is a normal star, latching read data, and after the waiting time is more than or equal to two preset durations, storing the star point, the number of the star points, the exposure time, the image SYNC star time, the image synchronization signal count, the image clock count and the background estimation value into a star map SRAM.
The purpose of the invention is realized by the following technical scheme:
a real-time reliable star point identification and storage method adopts a method of alternately using two dividers for flow operation and carrying out division calculation on star point data in FIFO. The method uses two FSM state machines to carry out logic realization, and comprises the following steps:
for FSM state machine 1:
state 100: circularly obtaining image frames until the number of data in the FIFO of the gray value accumulation sum is greater than 0, and transferring to a state 101;
state 101: after the read data is latched, alternately starting a divider 1 and a divider 2; the conditions for alternately starting divider 1 and divider 2 are: after the divider 1 is started, if the timing time is longer than three system clocks and the number of data in FIFO of the gray value accumulation sum of the image frames is larger than 0, the divider 2 is started; after the divider 2 is started, if the operation of the divider 1 is finished and the number of data in the FIFO of the gray value accumulation sum of the image frame is more than 0, the divider 1 is started; setting the last star point mark signal until the image frame is finished, and transferring to the state 100;
for FSM state machine 2: judging when the operation of the divider 1 or the divider 2 is finished; if the current star point is not the last star point of the image frame and is a pseudo star, the star point transmission has no action; if the current star point is not the last star point of the image frame and is a normal star, latching read data; if the current star point is the last star point of the image frame and is a pseudo star, the star point transmission has no action, and the star point number, the exposure time, the image SYNC star time, the image synchronization signal count, the image clock count and the background estimation value are stored in a star map SRAM; and if the current star point is the last star point of the image frame and is a normal star, latching read data, and after the waiting time is more than or equal to two preset durations, storing the star point, the number of the star points, the exposure time, the image SYNC star time, the image synchronization signal count, the image clock count and the background estimation value into a star map SRAM.
Preferably, the method for real-time and reliable star point identification and storage includes the following steps:
if the number of pixels in any pixel block is larger than the upper limit value of the number of strong light pixels, setting a strong light interference mark and judging the strong light interference mark as a pseudo star;
in a certain star image spot, if the number of pixels with the gray level higher than the highlight gray level threshold is larger than the highlight pixel number threshold, setting a highlight mark and judging the highlight mark as a pseudo star;
the pixel block with the pixel number smaller than the lower limit value of the pseudo star pixel number or larger than the upper limit value of the pseudo star pixel number is judged as a pseudo star;
judging the pixel block with only 1 row or 1 column as a pseudo star;
for the pixel block with only two rows, if the number of columns is less than or equal to the number of columns of two rows of pixel blocks, and the difference between the number of pixels in the two rows is less than or equal to the pixel difference between the two rows of pixel blocks, judging the pixel block as a true star, otherwise, judging the pixel block as a false star;
for pixel blocks with only two columns, if the number of rows is less than or equal to that of the pixel blocks in the two columns, and the difference between the number of pixels in the two columns is less than or equal to that of the pixel blocks in the two columns, the pixel blocks are judged to be true stars, otherwise the pixel blocks are false stars;
if one of the number of lines or the number of columns is larger than the maximum value of the star point row-column, judging the pseudo star;
the pixel block row span is the absolute value of the difference between the row coordinates of the uppermost pixel and the row coordinate of the lowermost pixel, and the column span is the absolute value of the difference between the column coordinates of the leftmost pixel and the rightmost pixel, if any: and (line span multiplied by column span)/total number of pixels is more than or equal to the ratio of star point areas, and the pseudo star is judged.
Preferably, if the current star point is the last star point of the image frame and is a normal star, the data storage is required. The latched data comprises star points, the number of the star points, exposure time, image SYNC star time, image synchronous signal counting, image clock counting, background evaluation value and the like, and is stored in the FPGA star map SRAM, and then the state machine is quitted to wait for starting the next star point storage. In the storage process of the normal star, if the waiting time is shorter than the time length of two (star point calculation + storage period), continuing to wait; if the waiting time is longer than or equal to the time length of two (star point calculation + storage period), the 'supplementary operation mark' con _ star is set to '0', and the storage operation of the last normal star point is finished.
Preferably, if the current star point is the last star point of the image frame and is a pseudo star, the star point transmission has no action, and the storage mark store tick signal is not generated without storing the related data of the pseudo star point. And only the star point number, the exposure time, the image SYNC star time, the image synchronization signal count, the image clock count and the background evaluation value are stored in the FPGA star map SRAM. The state machine operation may also be exited upon non-detection of the store flag store tick.
According to the real-time reliable star point identification and storage method, preferably, each preset time duration of the waiting time is the sum of the star point calculation time duration and the storage period.
An electronic device, comprising:
a processor; and
a memory for storing computer program instructions;
wherein when the computer program instructions are loaded and run by the processor, the processor performs the above-described real-time reliable star point identification and storage method.
Compared with the prior art, the invention has the following beneficial effects:
(1) the method of the invention uses a method of externally connecting two dividers with FIFO to realize the running water treatment of the ping-pong divider and ensure that a plurality of star points with too close distance are not lost in the treatment process. Meanwhile, the high-speed real-time star point identification processing under the limited resources is realized through a logic structure which collects and processes simultaneously.
(2) The method of the invention uses the image transmission end mark final _ star to trigger the 'supplementary operation flow cycle', ensures that the last effective star point can still have sufficient time sequence margin to be calculated and stored properly after the image transmission is finished.
(3) The method judges the pseudo star identifier star _ flag in the 'supplement operation flow period', ensures that the state machine can safely quit without causing deadlock on function when the last star point is the pseudo star and the state machine cannot detect the store storage identifier, namely, the pseudo star is not stored.
Drawings
FIG. 1 is an overall functional block diagram of the method of the present invention.
FIG. 2 is a schematic diagram of an image processing flow of the method of the present invention.
FIG. 3 is a pseudo star determination flowchart of the method of the present invention.
FIG. 4 shows the implementation process of ping-pong pipeline processing by the method of the present invention, in which two dividers externally connected to FIFO operate alternately.
FIG. 5 is a process for implementing the method of the present invention using the image transmission end flag final _ star to trigger "supplementary operation flow cycle".
FIG. 6 is a process for implementing the method of the present invention to ensure safe exit from the state machine by using the decision of the star identifier star _ flag in the "supplementary operation flow period".
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
According to different requirements of the system, the invention utilizes the FPGA for the requirements of speed and accuracy of functions of receiving and preprocessing images of the CCD camera, downloading the images and the like, and uses a ping-pong flow design mode of a divider externally connected with an FIFO in a star point distinguishing stage in a flow and a pseudo star distinguishing process aiming at a plurality of star points, thereby avoiding the situation that effective star points are lost when adjacent star points are close in distance. In order to ensure strong real-time calculation and storage, the invention uses the image transmission end mark to trigger a 'supplementary operation flow cycle' when high-speed star image processing is carried out, and ensures that the last star point is completely stored. The invention judges whether the pseudo star exists in the 'supplement operation flow period', ensures that the pseudo star can be safely exited under the condition of not storing the pseudo star, and improves the reliability of the system. The method and the device can intuitively, quickly and accurately improve the guidance navigation operation efficiency of the GNC subsystem, and have wide application prospect due to the design universality.
The overall functional block diagram of the present invention is shown in fig. 1.
1. Pseudo star distinguishing method
The composition and basic processing flow of the image processing module is shown in fig. 2. The pseudo star discrimination specific algorithm is as follows:
step one, if the number of pixels in any pixel block is larger than the upper limit value of the number of strong light pixels, setting a strong light interference mark and judging the strong light interference mark as a pseudo star;
step two, in a certain star image spot, if the number of pixels with the gray level higher than the highlight gray level threshold is larger than the highlight pixel number threshold, setting a highlight mark and judging the highlight mark as a pseudo star;
step three, judging the pixel block with the pixel number (total effective star point number) smaller than the lower limit value of the pseudo star pixel number or larger than the upper limit value of the pseudo star pixel number as a pseudo star;
step four, judging the pixel block with only 1 row or 1 column as a pseudo star;
step five, regarding the pixel block with only two rows of rows, if the number of columns is less than or equal to the number of columns of two rows of pixel blocks, and the difference between the number of pixels in the two rows is less than or equal to the pixel difference between the two rows of pixel blocks, judging the pixel block as a true star, otherwise, judging the pixel block as a false star;
step six, regarding pixel blocks with only two columns of columns, if the number of rows is less than or equal to the number of rows of two columns of pixel blocks, and the difference between the number of pixels in the two columns is less than or equal to the pixel difference between the two columns of pixel blocks, judging the pixel blocks as true stars, otherwise, judging the pixel blocks as false stars;
seventhly, if one of the number of rows or the number of columns is larger than the maximum value of the star point row-column, judging the star as a pseudo star;
step eight, pixel block row span is the absolute value of the difference between the row coordinates of the uppermost pixel and the lowermost pixel, and column span is the absolute value of the difference between the column coordinates of the leftmost pixel and the rightmost pixel, if yes: and (line span multiplied by column span)/total number of pixels is more than or equal to the ratio of star point areas, and the pseudo star is judged.
The flow chart is shown in fig. 3, wherein in step eight "(row span x column span)/total number of pixels" is the place where the divider is needed to calculate in the present invention.
2. Window star point identification method
The specific implementation process of the state machine of the window star point judgment module is as follows:
FSM state machine 1:
state 0: if an image frame starts, clearing the data in the gray value accumulation and FIFO, and transferring the state to the state 1;
state 1: if the number of data in the FIFO of the gray value accumulated sum is greater than 0, starting a data reading signal, and transferring the state to a state 2, otherwise, circulating in the state 1;
state 2: clearing the read data starting signal, and transferring the state to a state 3;
state 3: keeping a read data starting signal clearing state, latching read data, and transferring the state to a state 4;
and 4: starting the divider 1, and making a state transition to a state 5;
and state 5: if an image frame is finished, setting a last star point mark signal, and transferring the state to a state 0;
waiting for the timing time to be longer than three system clocks, if the number of data in the FIFO of the gray value accumulated sum is larger than 0, starting a data reading signal, and transferring the state to a state 6, otherwise, circulating in a state 5;
and 6: clearing the read data starting signal, and transferring the state to the state 7;
and state 7: keeping the clear state of the read data starting signal, latching the read data, and transferring the state to a state 8;
state 8: starting the divider 2, and making a state transition to a state 9;
state 9: if an image frame is finished, setting a last star point mark signal, and transferring the state to a state 0;
waiting for the ending mark of the divider 1 to be set to be '1', if the number of data in the FIFO of the gray value accumulated sum is greater than 0, starting a data reading signal, and transferring the state to a state 10, otherwise, circulating in a state 9;
state 10: clearing the read data start signal and making the state transition to the state 11;
state 11: keeping a read data starting signal clearing state, latching read data, and transferring the state to a state 4;
FSM state machine 2:
state 0: clearing a pseudo star judgment result, clearing a pseudo star mark, clearing a last star point mark signal and transferring the state to a state 1;
state 1: if an image frame is finished, setting a last star point mark signal, and transferring the state to a state 2; .
State 2: waiting for a calculation end mark of the divider 1, and if the calculation end mark is detected, transferring the state to a state 3;
state 3: and adopting a pseudo star distinguishing method to distinguish pseudo stars.
And 4: and waiting for the judgment of the pseudo star to end.
If the star point is not the last star point, the state transitions to state 1. If the satellite is a pseudo satellite, the star point transmission end mark tick signal has no action; if the star point is a normal star, the read data is latched;
if the star point is the last star point, the state transitions to state 0. If the satellite is a pseudo satellite, the star point transmission end mark tick signal has no action; if the star point is a normal star, the read data is latched;
and state 5: waiting for the calculation end mark of the divider 2, and if the calculation end mark is detected, transferring the state to a state 6;
and 6: and adopting a pseudo star distinguishing method to distinguish pseudo stars.
And state 7: and waiting for the judgment of the pseudo star to end.
If the star point is not the last star point, the state transitions to state 1. If the satellite is a pseudo satellite, the star point transmission end mark tick signal has no action; if the star point is a normal star, the read data is latched;
if the star point is the last star point, the state transitions to state 0. If the satellite is a pseudo satellite, the star point transmission end mark tick signal has no action; if the star point is a normal star, the read data is latched;
in the pseudo star distinguishing process, the problem that the star is lost due to the fact that subsequent star points cannot be calculated and stored when the star points arrive and the divider is occupied can be solved. When the internal resources of the FPGA are under the limited condition, namely at most two dividers can be instantiated, the method adopts a ping-pong pipeline processing mode of the two dividers externally connected with the FIFO in the fake star distinguishing process, and avoids the condition that effective star points are lost when the adjacent follow-up star points are close to each other. As shown in fig. 4.
3. Delay design aiming at time when last star point is normal star and data needs to be stored
The invention aims to solve the problem that the last star point result cannot be stored in the star point storage process. After the final star point signal final _ star comes, a logic step needs to be added to ensure that the final valid star point can finish the operation and finish the storage.
State 0: the "supplementary operation flag" con _ star is cleared, and the state transitions to state 1;
state 1: if final _ star comes, setting 'supplementary operation flag' con _ star to '1', and making the state transition to state 2;
state 2: waiting for the timing time, and if the waiting time is less than the duration of two (star point calculation + storage period), circulating in a state 2; if the waiting time is longer than or equal to the duration of two (star point calculation + storage period), "supplementary operation flag" con _ star is set to "0", and the storage operation is ended. State transition to state 1;
in the method, after final _ star arrives, a 'supplementary operation mark' con _ star is set to be '1', and after the duration of two star operation storage periods lasts, the last star is ensured to be set to be '0' after the calculation and the storage of the last star are finished. And finishing the operation of star point identification operation and result storage of the whole frame of image by using the falling edge of con _ star, thereby avoiding the omission of the last star point. As shown in fig. 5.
4. Storage process design for last star point
The image storage module needs to provide a star map RAM for storing star map related data processed by a full map mode and a window mode. The star map RAM is realized by using a RAM block inside the FPGA, and provides interfaces for processor access (reading and writing) and FPGA internal access (writing). The image storage module latches the values of currently used integration time, image SYNC star time, image synchronization signal count, image clock count and background evaluation value, and stores the values into the star map SRAM.
In the capture mode, if the number of continuously stored star point pixels is greater than or equal to the maximum allowed number or less than or equal to the minimum allowed number (for 2 rows of images processed simultaneously, the two pixel columns are the same or adjacent and are considered to be continuous), the storage of the continuous star point pixels is abandoned.
In the capture mode, the implementation process of the whole-image star point information storage module is as follows:
state 0: clearing the effective pixel count, clearing the data storage address, clearing the writing flag tick signal of the image preprocessing data RAM, clearing the writing address of the image preprocessing data RAM, clearing the writing data array of the image preprocessing data RAM, clearing the last star point flag and clearing the latch data register. If the image preprocessing frame starting flag array tick signal is set, the state is transferred to the state 1, otherwise, the state is circulated in the state 0;
state 1: and starting to store the star points.
If the star point is a pseudo star, the state is transferred to the state 8, after the state is sequentially transferred to the state 14 from the state 8, the state 14 can jump to the state 0, and the operation of returning the state machine to zero is carried out, so that the problems that the state machine cannot return to zero and the state cannot jump out in the state machine due to the fact that whether the star point is the pseudo star or not is not judged are solved.
If the star point is a normal star and the storage star point flag signal is in the activated state, the state transitions to state 2. Adding one to the effective pixel count, and latching data of gray sum, gray sum and row number product, gray sum and column number product, star point pixel number, star point number of lines and star point number of columns; this case uses the operation of the delay design for the storage process as described in embodiment 3. The "supplementary operation flag" con _ star sets "1" when starpoint storage is started, indicating that storage is started, and sets "0" only when the waiting time is equal to or longer than two (the starpoint calculation + the storage period), indicating that storage is ended.
If the storage star point mark signal is not started, circulating in a state 1;
if the image preprocessing frame finishes marking the set of tick signals, the last star point mark is set;
state 2: setting a writing mark of an image preprocessing data RAM, storing the product of the gray level and the line number of the image preprocessing data, adding one to a data storage address, and transferring the state to a state 3;
state 3: setting a writing mark of an image preprocessing data RAM, storing the product of the gray level and the column number of the image preprocessing data, adding one to a data storage address, and transferring the state to a state 4;
and 4: setting a writing mark of an image preprocessing data RAM, storing the number of star points of the image preprocessing data, adding one to a data storage address, and transferring the state to a state 5;
and state 5: setting a writing mark of an image preprocessing data RAM, storing the number of lines occupied by star points of the image preprocessing data, adding one to a data storage address, and transferring the state to a state 6;
and 6: if the last star point flag is set or the valid pixel count is greater than 110, the state transitions to state 8, otherwise the state transitions to state 1;
state 8: setting a writing mark of the image preprocessing data RAM, storing the star point number, returning the data storage address to the initial address of the image preprocessing data storage, and transferring the state to a state 10;
state 10: setting a writing mark of an image preprocessing data RAM, storing exposure time, returning a data storage address to an exposure time storage address, and transferring the state to a state 11;
state 11: setting a writing mark of the image preprocessing data RAM, storing an image SYNC star time, returning a data storage address to an image SYNC star time storage address, and transferring the state to a state 12;
state 12: setting a writing flag of the image preprocessing data RAM, storing an image synchronization signal count, returning a data storage address to an image synchronization signal count storage address, and transferring the state to a state 13;
state 13: setting a writing flag of the image preprocessing data RAM, storing image clock count, returning a data storage address to an image clock count storage address, and transferring the state to a state 14;
state 14: setting a writing mark of an image preprocessing data RAM, storing sum information, returning a data storage address to a checksum storage address, and transferring the state to a state 0;
in the star point storage process, in order to solve the abnormal situation that the state machine cannot exit, the operation of distinguishing the pseudo star mark needs to be added in the last star point storage process at this time so as to realize the reliable design of effective star point storage and safe exit of the state machine, as shown in fig. 6.
Those skilled in the art will appreciate that those matters not described in detail in the present specification are well known in the art.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications of the present invention without departing from the spirit and scope of the present invention by using the methods and technical contents disclosed above.
Claims (6)
1. A real-time reliable star point identification and storage method is characterized in that two FSM state machines are adopted, and the method comprises the following steps:
for FSM state machine 1:
state 100: circularly obtaining image frames until the number of data in the FIFO of the gray value accumulation sum is greater than 0, and transferring to a state 101;
state 101: after the read data is latched, alternately starting a divider 1 and a divider 2; the conditions for alternately starting divider 1 and divider 2 are: after the divider 1 is started, if the timing time is longer than three system clocks and the number of data in FIFO of the gray value accumulation sum of the image frames is larger than 0, the divider 2 is started; after the divider 2 is started, if the operation of the divider 1 is finished and the number of data in the FIFO of the gray value accumulation sum of the image frame is more than 0, the divider 1 is started; setting the last star point mark signal until the image frame is finished, and transferring to the state 100;
for FSM state machine 2: judging when the operation of the divider 1 or the divider 2 is finished; if the current star point is not the last star point of the image frame and is a pseudo star, the star point transmission has no action; if the current star point is not the last star point of the image frame and is a normal star, latching read data; if the current star point is the last star point of the image frame and is a pseudo star, the star point transmission has no action, and the star point number, the exposure time, the image SYNC star time, the image synchronization signal count, the image clock count and the background estimation value are stored in a star map SRAM; and if the current star point is the last star point of the image frame and is a normal star, latching read data, and after the waiting time is more than or equal to two preset durations, storing the star point, the number of the star points, the exposure time, the image SYNC star time, the image synchronization signal count, the image clock count and the background estimation value into a star map SRAM.
2. The real-time reliable star point identification and storage method according to claim 1, wherein the pseudo star discrimination method comprises the following steps:
if the number of pixels in any pixel block is larger than the upper limit value of the number of strong light pixels, setting a strong light interference mark and judging the strong light interference mark as a pseudo star;
in a certain star image spot, if the number of pixels with the gray level higher than the highlight gray level threshold is larger than the highlight pixel number threshold, setting a highlight mark and judging the highlight mark as a pseudo star;
the pixel block with the pixel number smaller than the lower limit value of the pseudo star pixel number or larger than the upper limit value of the pseudo star pixel number is judged as a pseudo star;
judging the pixel block with only 1 row or 1 column as a pseudo star;
for the pixel block with only two rows, if the number of columns is less than or equal to the number of columns of two rows of pixel blocks, and the difference between the number of pixels in the two rows is less than or equal to the pixel difference between the two rows of pixel blocks, judging the pixel block as a true star, otherwise, judging the pixel block as a false star;
for pixel blocks with only two columns, if the number of rows is less than or equal to that of the pixel blocks in the two columns, and the difference between the number of pixels in the two columns is less than or equal to that of the pixel blocks in the two columns, the pixel blocks are judged to be true stars, otherwise the pixel blocks are false stars;
if one of the number of lines or the number of columns is larger than the maximum value of the star point row-column, judging the pseudo star;
the pixel block row span is the absolute value of the difference between the row coordinates of the uppermost pixel and the row coordinate of the lowermost pixel, and the column span is the absolute value of the difference between the column coordinates of the leftmost pixel and the rightmost pixel, if any: the total number of (line span multiplied by column span)/pixels is more than or equal to the ratio of the star point area, and the satellite is judged to be a pseudo-star;
and if the current star point is the last star point of the image frame and is a normal star, latching read data, and after the waiting time is more than or equal to two preset durations, storing the star point, the number of the star points, the exposure time, the image SYNC star time, the image synchronization signal count, the image clock count and the background estimation value into a star map SRAM.
3. The real-time reliable star point identification and storage method according to claim 1, wherein if the current star point is the last star point of the image frame and is a normal star, data storage is required; latching data comprises star points, star point numbers, exposure time, image SYNC star time, image synchronization signal counting, image clock counting and background evaluation, and after the latching data is stored in an FPGA star map SRAM, exiting a state machine to wait for starting the next star point storage; in the storage process, after the waiting time is more than or equal to two preset durations, the mark bit is set.
4. A real-time reliable star point identification and storage method according to claim 3 wherein each predetermined duration of the wait time is the sum of the star point calculation duration and the storage period.
5. The method as claimed in claim 1, wherein if the current star point is the last star point of the image frame and is a pseudo star, the star point transmission has no action, and does not need to store the data related to the pseudo star point and does not generate a storage flag signal.
6. An electronic device, comprising:
a processor; and
a memory for storing computer program instructions;
wherein when the computer program instructions are loaded and executed by the processor, the processor performs the method of any of claims 1 to 5.
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