CN1811591A - Medical CCD camera and corresponding X-ray machine exposure controlling method - Google Patents

Medical CCD camera and corresponding X-ray machine exposure controlling method Download PDF

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CN1811591A
CN1811591A CN200610041869.6A CN200610041869A CN1811591A CN 1811591 A CN1811591 A CN 1811591A CN 200610041869 A CN200610041869 A CN 200610041869A CN 1811591 A CN1811591 A CN 1811591A
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time
exposure
image
ray machine
ccd
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CN100561333C (en
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牟轩沁
邹屹洋
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Xian Jiaotong University
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Xian Jiaotong University
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Abstract

The present invention discloses a medical CCD camera and correspondent X-ray machine exposure control method. Said invention utilizes short exposure, pre-exposure, first weak reading-out and secondary weak reading-out method to calculate the exposure termination time of this X-ray machine exposure. In the X-ray machine exposure control method the interface of X-ray controller is basically identical to the interface of traditional X-ray machine exposure controller, the CCD quick reading-out method can make the processes of pre-exposure, short exposure and weak reading-out, etc. be implemented within 1-several milliseconds, and the circuits of calculation module and time sequence control module can extensively select existent various embedded computing chips, including DSP, ARM and FPGA, so that it can calculate exposure time of X-ray machine within submillisecond level time, and can raise imaging quality of X-ray machine.

Description

Medical CCD camera and corresponding X-ray machine exposal control method
Technical field
The invention belongs to medical science X-ray imaging field, relate to a kind of automatic exposure control method and device in the X-ray imaging, particularly do not need the traditional optical signal feedback, based on the X-ray machine Control Technique for Automatic Exposure and the corresponding video camera of exposure prediction and calculation.
Background technology
In x-ray imaging, in general, roentgen dose X is big more, and the quality of image is good more.But in yet another aspect, the big more injury to the patient of dosage is also just big more.So Control Technique for Automatic Exposure is occupied important role in x-ray imaging.
The suffered x-ray dose of patient is mainly by the bulb voltage (kVp) of X-ray machine, bulb electric current and the product (mAs) that the time is set, and the distance between bulb and the patient, and may between bulb and object, any decay of path decide.Wherein, in automatic exposure control, mainly regulate mAs.
The X-ray imaging mainly divides three kinds of patterns, perspective imaging, spot film imaging, contrast imaging.Main spot film imaging and the contrast imaging paid close attention among the present invention; When spot film imaging or contrast imaging, two kinds of traditional control methods are arranged, and a kind of is after the exposure beginning, by ionization chamber (Ionization chamber), the intensity of detecting x-ray, this intensity is converted into a current value, behind the integrator integration, compares with a predefined magnitude of voltage, if greater than this magnitude of voltage, then send out end exposure and give the X lane controller, stop the X-ray machine exposure, it is used that this method is generally film imaging.Second method is in the image amplifier rear end, and (photodetector) surveys light intensity with photomultiplier, and method thereafter is identical with said method.This method is generally video camera imaging and adopts.Exposal control method has several shortcomings: at first, the adding of ionization chamber and photomultiplier has increased the complexity of whole X-ray machine.Secondly, the cost of ionization chamber and photomultiplier is all than higher.
Summary of the invention
The objective of the invention is to overcome above-mentioned prior art deficiency, a kind of medical CCD camera and corresponding X-ray machine exposal control method are provided, directly control the X lane controller, finished the exposure control function, simplify the connection of X-ray machine, can effectively reduce X-ray machine complexity and cost.
Technical scheme of the present invention is achieved in that a kind of video camera of controlling the X-ray machine exposure, comprises CCD chip, sensing circuit, analog to digital conversion circuit, time-sequence control module, computing module; Camera lens is exported optical focus at the CCD chip with the video imaging device of X-ray machine, and the output of the simulating signal of CCD chip is connected on the analog to digital conversion circuit, and sensing circuit is made of level transferring chip, and output is connected on the CCD chip; Analog to digital conversion circuit is made up of variable gain amplifier and analog to digital converter, and this module one tunnel output is connected on the computing module, and one tunnel output is as the output of video camera; Computing module is realized on digital signal processing chip that by software programming time-sequence control module is received in this module output; Time-sequence control module receives the input of X-ray machine control panel, and the X lane controller is received in the output of time-sequence control module, sensing circuit and analog to digital conversion circuit; The X lane controller is connected to x-ray generator; X-ray generator sends the X line, and the video imaging device transfers the X-ray line to luminous ray.
Described time-sequence control module comprises: controller, counter, clock generator, fast shift sequential generation module, normally shift sequential generation module, read output signal generation module, substrate signal generating module, MUX; The X-ray machine control panel is input to controller, and controller outputs to counter, MUX, X lane controller, analog to digital conversion circuit respectively; Clock generator outputs to the analog to digital conversion circuit sum counter; Computing module is input to counter, counter output to respectively controller, fast shift sequential generation module, normally shift sequential generation module, read output signal generation module, substrate signal generating module; Shift sequential generation module fast and normally shift sequential generation module and all output to MUX; MUX, read output signal generation module and substrate signal generating module all output to sensing circuit.Shift the count value of sequential generation module fast according to counter, produce horizontal transfer and the vertical transitions sequential of CCD, and produce the transfer sequential of CCD chip at vertical direction vertical combining arranged side by side, the significant level duration of the vertical transfer clock in the vertical transitions sequential of this module, the sequential that claims this module to send was called quick transfer sequential than between short 100 to 1000 times of the time of normal vertical transitions data in the next line; The normal count value that shifts sequential generation module according to counter, produce the horizontal transfer and the vertical transitions sequential of CCD chip, the vertical transitions direction of this module is not carried out side by side, and the transfer significant level duration of the transfering clock in this vertical transitions sequential is the 1-10 microsecond; The sequential that claims this module to send is the normal sequential that shifts; Read output signal generation module produces read output signal and is connected to sensing circuit according to the count value of counter, and read output signal can change the duration of read output signal significant level under the control of counter; The substrate signal generating module according to the count value of counter, produces the substrate signal; MUX connects and to shift sequential generation module fast, normally shifts sequential generation module, according to the selection of controller, wherein road signal is sent as output signal;
Utilize the method for above-mentioned video camera control X-ray machine exposure to divide four kinds:
Method one: comprise in the double exposure of X-ray machine, CCD exposed twice in the corresponding time, wherein the time shutter first time of X-ray machine is less than 1 millisecond, be called pre-exposure, exposure for the second time is called formal exposure, the CCD chip of the method can use interline transfer CCD and frame transfer CCD, claims that the method is the pre-exposure method, and step is as follows:
1) operation control panel is set the X lane controller, and according to providing bulb electric current mA with irradiated site, bulb voltage kVp produces X ray; Simultaneously, the video camera time-sequence control module is sent out the exposure that the substrate signal begins CCD, and the exposure of X-ray machine and the exposure of CCD this time is called pre-exposure;
2) process is less than after 1 millisecond time, and time-sequence control module is sent out the exposure stop signal to the X lane controller, and the control X-ray machine stops to produce X ray, and simultaneously, time-sequence control module [4] is sent out read output signal, end CCD exposure; Pre-exposure finishes;
3) time-sequence control module sends quick transfer sequential to sensing circuit, sensing circuit produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip, electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit, analog to digital conversion circuit transfers the analog level output of CCD to data image signal, produces the pre-exposure image;
4) the video camera computing module is by the pre-exposure image, and formally the required time shutter of exposure feeds back to time-sequence control module to calculate X-ray machine;
5) time-sequence control module is sent out the exposure commencing signal to the X lane controller, and X-ray machine begins formal exposure, and simultaneously, time-sequence control module is sent out the substrate signal, and the CCD chip begins formal exposure;
6) time-sequence control module is sent out the end exposure signal to the X lane controller when the time shutter of setting arrives, and finishes the X-ray machine exposure; Simultaneously, time-sequence control module is sent out read output signal, finishes the CCD current exposure;
7) time-sequence control module sends normal transfer sequential to sensing circuit, sensing circuit produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip, electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit, analog to digital conversion circuit transfers the analog level output of CCD to data image signal, produces output image.
The computing module of described X-ray machine exposal control method goes out X-ray machine by the pre-exposure image calculation, and formally the required time shutter of exposure may further comprise the steps:
1), obtains the feature gray scale of image from the pre-exposure image; The calculating of feature gray scale has following method:
I. calculate the average gray value of entire image;
Ii. on image, set 1 to 10 area-of-interest, calculate the average image gray-scale value of area-of-interest;
Iii. set the weighting coefficient of gradation of image around area-of-interest and its, calculate area-of-interest and the weighted mean of image around it;
2), calculate the formal time shutter of X-ray machine by formula (1):
T total = E m E pre * T pre - - - ( 1 )
Wherein, E mThe average gray of output image when representing CCD to reach maximum dynamic range, E PreRepresent the feature gray scale of pre-exposure image, T PreRepresent the time of X-ray machine pre-exposure; T TotalThe time of the formal exposure of expression X-ray machine.
Method two: comprise the double exposure of the single exposure and the CCD of X-ray machine, the CCD chip of the method can use interline transfer CCD and frame transfer CCD, claims that the method is the short exposure method, may further comprise the steps:
1) operation X-ray machine control panel is set the X lane controller, provides mA according to irradiated site, and kVp produces X ray; Simultaneously, time-sequence control module is sent out this exposure that the substrate signal begins CCD; The exposure of CCD this time is called short exposure;
2) process is less than after 1 millisecond time, and time-sequence control module is sent out read output signal, and end CCD chip is integral time this time, finishes the CCD exposure; Short exposure finishes;
3) time-sequence control module is exported different signals at the kind of CCD chip; For interline transfer CCD, time-sequence control module produces read output signal to sensing circuit, and sensing circuit produces reads level, and the electric charge that drives interline transfer CCD is transferred to the vertical transitions register from pixel; For frame transfer CCD, time-sequence control module produces and shifts sequential fast to sensing circuit, and sensing circuit produces vertical transfer clock, and the driven CCD electric charge is transferred to storage from imaging area;
4) time-sequence control module is sent out the integration that the substrate signal begins the formal exposure of CCD;
5) time-sequence control module sends quick transfer sequential to sensing circuit, sensing circuit produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip, electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit, analog to digital conversion circuit transfers the analog level output of CCD to data image signal, produces the short exposure image;
6) computing module is by the short exposure image, calculates this X-ray machine required time shutter of exposure to feed back to time-sequence control module;
7) time-sequence control module is sent out the end exposure signal to the X lane controller when the time shutter arrives, and finishes the X-ray machine exposure, and simultaneously, time-sequence control module is sent out read output signal, finishes the CCD exposure;
8) time-sequence control module sends normal transfer sequential to sensing circuit, sensing circuit produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip, electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit, analog to digital conversion circuit transfers the analog level output of CCD to data image signal, produces output image.
In this X-ray machine exposal control method, computing module comprises following step by the computing method of short exposure image calculation X-ray machine time shutter:
1), obtains the feature gray scale of image from the short exposure image; The computing method of feature gray scale are as follows:
I. calculate the average gray value of entire image;
Ii. on image, set 1 to 10 area-of-interest, calculate the average image gray-scale value of area-of-interest;
Iii. set the weighting coefficient of gradation of image around area-of-interest and its, calculate area-of-interest and the weighted mean of image around it;
2) by formula (2), calculate total time shutter of X-ray machine current exposure:
T total = E m E short * T short - - - ( 2 )
Wherein, E mThe average gray of output image when representing CCD to reach maximum dynamic range, E ShortRepresent the feature gray scale of short exposure image, T ShortWhen representative obtains the short exposure image, the time that X-ray machine has exposed; T TotalThe time that the total exposure of expression X-ray machine need be carried out;
Method three: twice readout that comprises CCD, effective duration of the read output signal in wherein reading for the first time is below 0.1 microsecond, read a little less than claiming this time to read as, the significant level duration of a back read output signal claims to read as normally specifically to read between 5 to 100 microseconds; The CCD chip of the method can only use interline transfer CCD; Claim this method to be weak reading method once, step is as follows:
1) operation X-ray machine control panel is set the X lane controller, provides mA according to irradiated site, and kVp produces X ray; Simultaneously, time-sequence control module is sent out this exposure that the substrate signal begins CCD;
2) after the time through the 1-5 millisecond, time-sequence control module is sent out a significant level and is continued the following read output signal of 0.1 microsecond, and the part of electric charge below 1% transferred in the vertical transitions register in the driven CCD pixel; This is read a little less than reading and being called;
3) time-sequence control module sends quick transfer sequential to sensing circuit, sensing circuit produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip, electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit, analog to digital conversion circuit transfers the analog level of CCD to data image signal, reads image a little less than the generation;
4) computing module is by the weak image of reading, and calculates this X-ray machine required time shutter of exposure to feed back to time-sequence control module;
When 5) time shutter of time-sequence control module arrives, send out the end exposure signal to the X lane controller, finish the X-ray machine exposure, simultaneously, time-sequence control module sends out read output signal normal, finishes CCD and exposes;
6) time-sequence control module sends normal transfer sequential to sensing circuit, sensing circuit produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip, electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit, analog to digital conversion circuit transfers the analog level of CCD to data image signal, produces output image.
The video camera computing module calculates the computing method of X-ray machine time shutter by the weak image of reading, and may further comprise the steps:
1), obtains the feature gray scale of image from the weak image of reading; The calculating of feature gray scale has following method:
I. calculate the average gray value of entire image;
Ii. on image, set 1 to 10 area-of-interest, calculate the average image gray-scale value of area-of-interest;
Iii. set the weighting coefficient of gradation of image around area-of-interest and its, calculate area-of-interest and the weighted mean of image around it;
2) by formula (3), (4) calculate this X-ray machine exposure required time:
E pre = τ t * E r - - - ( 3 )
T total = E m E pre * T pre - - - ( 4 )
Wherein, E PreA little less than obtaining, representative reads image constantly, the feature gray scale of CCD pixel; The read output signal significant level duration during the τ representative is normally read; The read output signal significant level duration in reading a little less than the t representative; E rRead the feature gray scale of image a little less than the representative; E mThe average gray of output image when representing CCD to reach maximum dynamic range, T PreWhen reading image a little less than representative obtains, the time that X-ray machine has exposed; T TotalExpression total time shutter of X-ray machine;
Method four: comprise the single exposure of X-ray machine, read for three times of CCD, read a little less than wherein preceding read as for twice, after once for normally reading; The CCD chip of the method can only use interline transfer CCD, claims that this method is the weak reading method of secondary, and step is as follows:
1) operation X-ray machine control panel is set the X lane controller, provides mA according to irradiated site, and kVp produces X ray.Simultaneously, the video camera time-sequence control module is sent out this exposure that the substrate signal begins CCD;
2) time of process 1-5 millisecond, time-sequence control module is sent out the following read output signal of significant level duration 0.1 microsecond, the part of electric charge below 1% that accumulates in the CCD pixel this moment transferred in the vertical transitions register, read a little less than claiming this time to read as the first time;
3) time-sequence control module sends quick transfer sequential to sensing circuit, sensing circuit produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip, electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit, analog to digital conversion circuit transfers the analog level of CCD to data image signal, reads image a little less than the generation for the first time;
4) pass through the 1-5 millisecond time, it is the following read output signal of 0.1 microsecond that time-sequence control module is sent out a duration again, and the part of electric charge below 1% that accumulates in the CCD pixel this moment transferred in the vertical transitions register, and this is read a little less than reading and being called for the second time;
5) time-sequence control module sends quick transfer sequential to sensing circuit, sensing circuit produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip, electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit, analog to digital conversion circuit transfers the analog level output of CCD to data image signal, reads image a little less than the generation for the second time;
6) computing module is read image a little less than twice, calculates total time shutter of X-ray machine to feed back to time-sequence control module;
7) time-sequence control module is sent out the end exposure signal to the X lane controller when the time shutter of setting arrives, and finishes the X-ray machine exposure, and simultaneously, time-sequence control module sends out read output signal normal, finishes CCD and exposes;
8) time-sequence control module sends normal transfer sequential to sensing circuit, sensing circuit produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip, electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit, analog to digital conversion circuit [3] transfers the analog level of CCD to data image signal, produces output image.
Described computing module is read image a little less than by two width of cloth, calculates the method for X-ray machine time shutter, and step is as follows:
1), obtains the feature gray scale of image from the weak image of reading; The calculating of feature gray scale has following method:
I. calculate the average gray value of entire image;
Ii. on image, set 1 to 10 area-of-interest, calculate the average image gray-scale value of area-of-interest;
Iii. set the weighting coefficient of gradation of image around area-of-interest and its, calculate area-of-interest and the weighted mean of image around it;
2) by formula (5), (6), (7) calculate this X-ray machine exposure required time:
E 0 = τ t 0 * E r 0 - - - ( 5 )
E 1 = τ t 1 * E r 1 - - - ( 6 )
T total = ( E m - E 1 ) * ( T 1 - T 0 ) E 1 - E 0 + T 1 - - - ( 7 )
Wherein, E 0, E 1Represent respectively for the first time, read constantly the feature gray scale of CCD pixel a little less than the second time; t 0, t 1Represent for the first time the read output signal significant level duration in reading a little less than the second time respectively; The read output signal significant level duration during the τ representative is normally read; E R0, E R1Represent for the first time the feature gray scale of reading image a little less than the second time respectively; T 0, T 1Represent respectively for the first time, read the time shutter of X-ray machine constantly a little less than the second time; E mThe average gray of output image when representing CCD to reach maximum dynamic range; T TotalExpression total time shutter of X-ray machine.
The present invention utilizes short exposure, pre-exposure, reads a little less than once, and the weak reading method of secondary can calculate end exposure time of this X-ray machine exposure.Control the control interface basically identical with the interface and the exposure of traditional X-ray ray machine of X lane controller in the X-ray machine exposal control method of the present invention.The quick reading method of CCD can be so that pre-exposure, short exposure, a little less than process such as read and can in 1 to several milliseconds times, finish.Existing various embedded computing chip comprises DSP, ARM, and FPGA makes computing module, and circuit such as time-sequence control module have choice widely, and powerful computing ability is arranged, can be according to the time shutter that calculates X-ray machine in the time of inferior Millisecond.
The present invention utilizes the control method of ccd video camera control X-ray machine exposure, for the complexity that reduces X-ray machine, improves the X-ray machine image quality, and reducing the suffered radiant quantity of patient has great function.
Description of drawings
Fig. 1 system functional block diagram of the present invention.
Fig. 2 time-sequence control module block diagram.
Fig. 3 pre-exposure method sequential chart.
Fig. 4 short exposure method sequential chart.
The once weak reading method sequential chart of Fig. 5.
The weak reading method sequential chart of Fig. 6 secondary.
The structural drawing of Fig. 7 interline transfer CCD.
The structural drawing of Fig. 8 frame transfer CCD.
Fig. 9 interline transfer CCD shifts sequential chart fast.
Figure 10 frame transfer CCD shifts sequential chart fast.
Accompanying drawing is specific embodiments of the invention;
Below in conjunction with accompanying drawing content of the present invention is described in further detail.
Embodiment
As shown in Figure 1, frame of broken lines inside is ccd video camera, and this video camera is by constituting with lower module:
1) the CCD chip 1
CCD chip 1 is used for changing the optical signalling of video imaging device into analog electrical signal; At CCD chip 1, the simulating signal of CCD chip 1 outputs on the analog-to-digital conversion module 3 camera lens with X-ray machine video imaging device output optical focus, and the TL translation level of CCD chip 1 is imported from sensing circuit 2; In video camera of the present invention, the CCD chip of employing is the interline transfer CCD of Kodak, model name KAI-1020M, and resolution is 1004 * 1004; Interline transfer CCD is applicable to all control methods of the present invention, and frame transfer CCD is applicable to pre-exposure method of the present invention and short exposure method.
2) sensing circuit 2
Sensing circuit 2 is made of level transferring chip, level transferring chip is connected on the sequential control mould 4, the sequential level that sends with time-sequence control module 4, these level comprise vertical transfer clock, the horizontal transfer clock, read output signal level, substrate signal level, be transformed into the level signal that meets 1 driving of CCD chip, output to CCD chip 1; In the video camera of the present invention, sensing circuit is made of the level transferring chip SN74ALVC164245 of company of Texas Instrument (TI), and this chip transfers the 3.3V level that time-sequence control module sends to the 5V level;
3) analog to digital conversion circuit 3
Analog to digital conversion circuit 3 is made up of variable gain amplifier and analog to digital converter, and variable gain amplifier is connected the output terminal of CCD chip 1, and 1 output of CCD chip is by being input to behind the variable gain amplifier in the analog to digital converter; Analog to digital converter one tunnel output is connected to computing module 5, this road output be pre-exposure, short exposure is read a little less than once, reads image a little less than the secondary; The image output that another road output is last exposure, this road output is exported as video camera; In the video camera of the present invention, what analog to digital converter adopted is the ADS807 chip of TI company, analog input can be transferred to the digital signal of 12 precision; What variable gain amplifier was used is the AD8330 chip of analog meter company (ANALOG DEVICE);
4) time-sequence control module 4
Tfi module is by realizing on the software programming digital signal processing chip.The X-ray machine control panel 20 of time-sequence control module 4 and X-ray machine is connected, the operator can be provided with the parameter of time-sequence control module 4 by X-ray machine control panel 20, in the pre-exposure method, the short exposure method, once weak reading method, select a kind of exposure control mode in the weak reading method of secondary, and can control the On/Off of whole video camera; Time-sequence control module 4 is connected with X lane controller 21, sends exposure beginning/end signal, the beginning and the end of the exposure of control X-ray machine; The output of time-sequence control module 4 is connected to sensing circuit 2, and the signal of transmission comprises the vertical transitions signal, horizontal transfer signal, read output signal, substrate signal; The gain control signal of time-sequence control module 4 transmission variable gain amplifiers and the change over clock of analog to digital converter are to analog to digital conversion circuit 3; The output of computing module 5 is connected to this module, is used to control the exposure control time of X-ray machine; Time-sequence control module 4 is by the VHDL programming in the video camera of the present invention, realizes on fpga chip.
5) computing module 5
Computing module 5 is realized on digital signal processing chip that by software programming this module realizes formula (1), (2), (3), (4), (5), (6), the computing method of (7); The input of this module is connected in one tunnel output of analog to digital conversion circuit [3], accepts pre-exposure, and short exposure is read a little less than once, reads image a little less than the secondary, and output is connected time-sequence control module 4, is used to control the X-ray machine time shutter.In the video camera of the present invention, this module is programmed by VHDL, realizes on fpga chip.
As shown in Figure 2, time-sequence control module 4 is made of big solid box inner module, comprises following functional module:
1) controller 6
Controller 6 is accepted the parameter setting of X-ray machine control panel, the operator can be provided with the parameter of time-sequence control module by control panel, in the pre-exposure method, the short exposure method, once weak reading method, select a kind of exposure control mode in the weak reading method of secondary, and can control the On/Off of whole video camera; Controller 6 is according to the count value of counter 7 and the exposure time signal that returns from computing module 5, and output exposure beginning/end signal is to the X lane controller; Controller 6 output amplifier gain control signals are to the variable gain amplifier of analog to digital conversion circuit 3; Controller output resets, zero clearing, set, counting begin stop signal to counter 7; Output selects signal to MUX 13, selects to be output as quick sequential generation module 9 or normal sequential generation module 10; In the video camera of the present invention, the change over clock that controller 6 mails to analog to digital conversion circuit can change between 20MHZ-40MHZ, and the gain margin of variable gain amplifier changes between 0-30DB.
2) counter 7
The count value respectively of counter 7 output to controller 6, fast shift sequential generation module 9, just often supervention is given birth to module 10, read output signal generation module 11, substrate signal generating module 12; The counting clock of counter 7 is from clock generator 8; The result of calculation of computing module 5 is input to counter, and the count value of counter is set; Counter have synchronous asynchronous reset, set, clock enable, count and function such as enable, all controlled device 6 controls of these functions;
3) clock generator 8
This module is sent clock to counter 7 and analog to digital conversion circuit 3, and this module is the most basic clock module in the whole video camera, and all clock signals are all controlled by this clock generator; In the video camera of the present invention, this module is realized by the phaselocked loop among the FPGA;
4) shift sequential generation module 9 fast
This module produces horizontal transfer and the vertical transitions sequential of CCD according to count cycle information, and produces the transfer sequential of CCD at vertical direction (vertical combining) arranged side by side; The significant level duration of the vertical transfer clock in the vertical transitions sequential of this module is than short certain ratio of the time of normal vertical transitions data in the next line; This ratio can be set between 100 to 1000; The sequential that claims this module to send is called quick transfer sequential; In video camera of the present invention, shift 9 of timing sequencers fast and shift sequential fast, its vertical direction is per 62 row and delegation, the row of last less than 62 abandons, and at last entire image is listed as 16 row; The significant level duration of the vertical transfer clock when video camera of the present invention normally shifts be 3.6 microseconds, in shifting fast, this time was 72 nanoseconds;
5) normally shift sequential generation module 10
This module produces the horizontal transfer and the vertical transitions sequential of CCD chip 1 according to the count value of counter 7; The vertical transitions direction of this module is not carried out side by side, but transferring in the CCD chip 1 horizontal transfer register 17 delegation of image delegation; The transfer significant level duration of the transfering clock in this vertical transitions sequential is longer; The scope of this time is several microseconds; The sequential that claims this module to send is the normal sequential that shifts;
6) read output signal generation module 11
This module produces read output signal to sensing circuit 2 according to the count value of counter 7; Read output signal can change the duration of read output signal significant level under the control of counter; In the video camera of the present invention, the read output signal significant level duration of normally reading is 8 to 15 microseconds, and in the weak reading method, this read output signal significant level duration was 50 nanoseconds;
7) the substrate signal generating module 12
This module produces the substrate signal of CCD chip 1 according to the count value of counter 7, outputs to sensing circuit 2;
8) MUX 13
MUX 13 connects and shifts sequential generation module 9 fast, normally shifts sequential generation module 10, according to the selection of controller 6, wherein road signal is issued to sensing circuit 2 as output signal;
As shown in Figure 3, X-ray machine exposure twice in the pre-exposure method, CCD chip 1 exposed twice in the corresponding time.The detailed process of pre-exposure method is as follows:
1) operator operates X-ray machine control panel 20 and sets X lane controller 22, provides bulb electric current mA according to patient figure and irradiated site, and bulb voltage kVp produces X ray; Simultaneously, 4 substrate signals of time-sequence control module are given CCD chip 1,1 exposure of beginning CCD chip.The exposure of X-ray machine and the exposure of CCD chip 1 this time is called pre-exposure;
2) through T 0Time, T 0Value is below 1 millisecond, and 4 exposures of time-sequence control module stop signal is controlled X-ray machine and stopped to produce X ray, and simultaneously, this module is sent out read output signal, finishes 1 exposure of CCD chip.Pre-exposure finishes.
3) time-sequence control module 4 sends quick transfer sequential to sensing circuit 2, sensing circuit 2 produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip 1, electric charge is under the driving of transfering clock in the CCD chip 1, output to analog to digital conversion circuit 3, analog to digital conversion circuit 3 transfers the analog level output of CCD chip 1 to data image signal, produces the pre-exposure image;
4) computing module 5 utilizes formula (1) to calculate the required time shutter T of the formal exposure of X-ray machine by the pre-exposure image 2, computing module 5 is with T 2Issue time-sequence control module 4;
(3), (4) two steps must be at T 1Constantly, finish in the moment that just X-ray machine stops to expose; T 1Be the time that spent of pre-exposure image transfer and computing module computation process institute spended time and;
5) 4 exposures of time-sequence control module commencing signal is to X lane controller 21, and x-ray generator 22 beginnings are with mA, and kVp produces ray, simultaneously, 4 substrate signals of time-sequence control module, beginning is exposure formally;
6) time-sequence control module 4 is worked as T 2Time finishes, and sends out the end exposure signal to X lane controller 21, finishes the X-ray machine exposure; Simultaneously, 4 read output signals of time-sequence control module finish CCD chip 1 current exposure;
7) time-sequence control module 4 sends normal transfer sequential to sensing circuit 2, sensing circuit 2 produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip 1, electric charge is under the driving of transfering clock in the CCD chip 1, output to analog to digital conversion circuit 3, analog to digital conversion circuit 3 transfers the analog level of CCD to data image signal, produces output image;
As shown in Figure 4, X-ray machine exposes once in the short exposure method, CCD exposure twice, and detailed process is as follows:
1) operation X-ray machine control panel 20 is set X lane controller 21, provides mA according to irradiated site, and kVp produces X ray; Simultaneously, 4 substrate signals of time-sequence control module begin this exposure of CCD chip 1; The exposure of CCD chip 1 this time is called short exposure;
2) through T 0Time, T 0Value is below 1 millisecond, and 4 read output signals of time-sequence control module finish CCD chip 1 integral time this time, finish 1 exposure of CCD chip; Short exposure finishes; At this moment, x-ray generator 22 does not quit work;
3) time-sequence control module 4 is exported different signals at the kind of CCD chip 1; For interline transfer CCD, time-sequence control module 4 produces read output signals to sensing circuit 2, and sensing circuit 2 produces reads level, the electric charge of driving interline transfer CCD from pixel 15 to vertical transitions register 14; For frame transfer CCD, time-sequence control module 4 produces and shifts sequential fast to sensing circuit 2, and sensing circuit 2 produces vertical transfer clock, and the driven CCD electric charge is transferred to memory block 19 from imaging area 18; T 1For finishing the required time of said process;
4) 4 substrate signals of time-sequence control module begin the integration of CCD chip 1 formal exposure;
5) time-sequence control module 4 sends quick transfer sequential to sensing circuit 2, sensing circuit 2 produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip 1, electric charge is under the driving of transfering clock in the CCD chip 1, output to analog to digital conversion circuit 3, analog to digital conversion circuit 3 transfers the analog level output of CCD to data image signal, produces the short exposure image;
6) computing module 5 utilizes formula (2) can calculate whole X-ray machine exposure required time by the short exposure image, and this time deducts T 0, T 1, both can obtain the time T that X-ray machine also need expose 2, computing module 5 is with T 2Send to time-sequence control module 4;
7) time-sequence control module 4 is at T 2During end, send out the end exposure signal, finish the X-ray machine exposure to X lane controller 21.Simultaneously, 4 read output signals of time-sequence control module finish 1 exposure of CCD chip;
8) time-sequence control module 4 sends normal transfer sequential to sensing circuit 2, sensing circuit 2 produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip 1, electric charge is under the driving of transfering clock in the CCD chip 1, output to analog to digital conversion circuit 3, analog to digital conversion circuit 3 transfers the analog level output of CCD chip 1 to data image signal, produces output image.
As shown in Figure 5, read in the control method a little less than once, X-ray machine exposes once, the CCD exposure once but readout is arranged twice, step is as follows:
1) operation X-ray machine control panel 20 is set X lane controller 21, provides mA according to irradiated site, and kVp produces X ray; 4 substrate signals of time-sequence control module begin this exposure of CCD chip 1 simultaneously;
2) through T 0Time, T 0Value is the 1-5 millisecond, and 4 significant levels of time-sequence control module continue the read output signal of t, and the part of driven CCD chip 1 pixel, 15 stored charges below 1% transferred in the vertical transitions register; The t value is below 0.1 microsecond; This is read a little less than reading and being called;
3) time-sequence control module 4 sends quick transfer sequential to sensing circuit 2, sensing circuit 2 produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip 1, electric charge is under the driving of transfering clock in the CCD chip 1, output to analog to digital conversion circuit 3, analog to digital conversion circuit 3 transfers the analog level output of CCD chip 1 to data image signal, reads image a little less than the generation;
4) video camera computing module 5 utilizes formula (3) by the weak image of reading, and (4) calculate this required time shutter of X-ray machine exposure, and this time deducts T 0Be that X-ray machine also needs time shutter T 1, computing module 5 is with T 1Send to time-sequence control module 4;
5) time-sequence control module 4 is worked as T 1During end, send out the end exposure signal, finish the X-ray machine exposure to X lane controller 21.Simultaneously, the read output signal that time-sequence control module 4 significant level duration are τ finishes the CCD exposure; τ value 5 to 100 microseconds;
6) time-sequence control module 4 sends normal transfer sequential to sensing circuit 2, sensing circuit 2 produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip 1, electric charge is under the driving of transfering clock in the CCD chip 1, output to analog to digital conversion circuit 3, analog to digital conversion circuit 3 transfers the analog level output of CCD chip 1 to data image signal, produces output image.
As shown in Figure 6, in the weak reading method of secondary, X-ray machine expose once, and 1 exposure of CCD chip once still has reads for three times:
1) operation X-ray machine control panel 20 is set X lane controller 21, provides mA according to irradiated site, and kVp produces X ray.Simultaneously, 4 substrate signals of video camera time-sequence control module begin this exposure of CCD chip 1;
2) through T 0Time, T 0Value 1-5 millisecond, 4 one significant level duration t of time-sequence control module 0Read output signal, the part of electric charge below 1% of accumulation in this moment CCD chip 1 pixel 15 transferred in the vertical transitions register 14; t 0Below value 0.1 microsecond; Read a little less than claiming this time to read as for the first time;
3) time-sequence control module 4 sends quick transfer sequential to sensing circuit 2, sensing circuit 2 produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip 1, electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit 3, analog to digital conversion circuit 3 transfers the analog level output of CCD chip 1 to data image signal, reads image a little less than the generation for the first time;
4) through T 1Time, video camera is read tfi module and is sent out a significant level duration t 1Read output signal, the part of stored charge below 1% in this moment CCD chip 1 pixel 15 transferred in the vertical transitions register 14; t 1Below value 0.1 microsecond; This is read a little less than reading and being called for the second time;
5) time-sequence control module 4 sends quick transfer sequential to sensing circuit 2, sensing circuit 2 produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip 1, electric charge is under the driving of transfering clock in the CCD chip 1, output to analog to digital conversion circuit 3, analog to digital conversion circuit 3 transfers the analog level output of CCD chip 1 to data image signal, reads image a little less than the generation for the second time.
6) video camera computing module 5 is read image a little less than twice, utilizes formula (5), and (6), (7) calculate total time shutter of X-ray machine, and this time deducts T 0, T 1The both time T that also need expose for X-ray machine 2, computing module 5 is with T 2Send to time-sequence control module 4;
7) time-sequence control module 4 is worked as T 2During end, send out the end exposure signal, finish the X-ray machine exposure to X lane controller 21.Simultaneously, the normal read output signal that time-sequence control module 4 significant level duration are τ finishes the CCD exposure; τ value 5-100 microsecond;
8) time-sequence control module 4 sends normal transfer sequential to sensing circuit 2, sensing circuit 2 produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip 1, electric charge is under the driving of transfering clock in the CCD chip 1, output to analog to digital conversion circuit 3, analog to digital conversion circuit 3 transfers the analog level output of CCD chip 1 to data image signal, produces output image.
As Fig. 7, shown in Figure 8, the difference of the structure of the structure of interline transfer CCD and frame transfer CCD is that interline transfer CCD does not possess a special memory block 19, but between pixel 15, there is vertical register 14, in vertical register 14, the conductively-closed of input light.And there is a memory block 19 in frame transfer CCD, in the memory block, and the conductively-closed of input light.Because the structure difference of these two kinds of CCD, so the quick transfer sequential of these two kinds of CCD is different.And because once weak reading method and the weak reading method of secondary need vertical register 14, so weak reading method only is applicable to interline transfer CCD.In pre-exposure method and the short exposure method, these two kinds of CCD are suitable for.
The method that CCD shifts fast is divided into the quick transfer method of interline transfer CCD and the quick transfer method of frame transfer CCD according to the design feature of CCD chip 1.For interline transfer CCD, after 4 read output signals of video camera time-sequence control module were transferred to the electric charge in the CCD pixel 15 in the vertical transitions register 14,4 vertical transitions sequential of time-sequence control module and horizontal transfer sequential shifted out with electric charge.For frame transfer CCD, the control of 4 read output signals of time-sequence control module indicates that just imaging area 18 electric charges transfer to memory block 19 beginnings, and then 4 vertical transitions sequential of time-sequence control module are transferred to memory block 19 with electric charge from imaging area 18, and then shift.
The quick transfer method of interline transfer CCD may further comprise the steps:
1) read output signal transfers to the vertical transitions register 14 with the CCD electric charge from pixel 15.
2) vertical transitions register 14, is transferred to multirow in the horizontal transfer register 17 under the effect of quick vertical transfer clock with behavior unit.
3) horizontal transfer register 17 is exported pixel by amplifier 16 under the effect of horizontal transfer clock.
The quick transfer method of frame transfer CCD may further comprise the steps:
1) after read output signal occurred, vertical transfer clock with behavior unit, was transferred to memory block 19 with electric charge from imaging area 18 in the effect of vertical transfer clock fast.
2) in the memory block, vertical transfer clock is transferred to the multirow of memory block in the horizontal shifting register fast.
3) the horizontal transfer register is exported pixel by amplifier 16 under the effect of horizontal transfer clock.
As shown in Figure 9, to be applied to a resolution be M * N interline transfer CCD to the quick transfer method of interline transfer CCD:
Remember that this image is M*N, note vertical moving time T once v, a time of horizontal transfer note T h, then read whole pixel T transfer time TotalCan represent with (8) formula.
T total＝M*T v+M*N*T h (8)
In order to reduce pixel transfer time, in the present invention, pre-exposure, short exposure, to read a little less than once, read reading of image a little less than the secondary be not that pixel is exported respectively one by one, but being merged into delegation, reads multirow, after soon the multirow electric charge of CCD will all move on in the horizontal transfer register 17, read again.Suppose to read M/A=X again after we are with the capable merging of A.Like this, we just obtain the image of an X*N, and according to formula (8), we can see second M*N*T hReduced A doubly.The transfer time of CCD is mainly by second decision.
Shifting in the sequential fast, the significant level duration of its vertical transfer clock can be than the significant level T of the vertical transfer clock in the normal transfer vLittle 100 to 1000 times, remember that this time is T FastLike this, last pre-exposure T readout time Pre_total:
T pre_total＝M*T fast+X*N*T h (9)
As shown in figure 10, the quick transfer method of the frame transfer row CCD frame transfer CCD that to be applied to a resolution be M * N.
Unique difference is that frame transfer CCD needs earlier the electric charge of imaging area to be transferred to the memory block fast with interline transfer CCD herein, and is identical with the analysis of Fig. 9.Last quick readout time T Pre_total:
T pre_total＝2*M*T fast+X*N*T h (10)

Claims (10)

1. a video camera of controlling the X-ray machine exposure comprises CCD chip [1], sensing circuit [2], analog to digital conversion circuit [3], time-sequence control module [4], computing module [5]; It is characterized in that, camera lens with the output optical focus of the video imaging device [23] of X-ray machine in CCD chip [1], the simulating signal output of CCD chip [1] is connected on the analog to digital conversion circuit [3], and sensing circuit [2] is made of level transferring chip, and output is connected on the CCD chip [1]; Analog to digital conversion circuit [3] is made up of variable gain amplifier and analog to digital converter, and this module one tunnel output is connected on the computing module [5], and one tunnel output is as the output of video camera; Computing module [5] is realized on digital signal processing chip that by software programming time-sequence control module [4] is received in this module output; The X lane controller [21] of time-sequence control module [4] and X-ray machine is connected with X-ray machine control panel [20]; Time-sequence control module [4] outputs to sensing circuit [2] and analog to digital conversion circuit [3]; X lane controller [21] is connected to x-ray generator [22]; X-ray generator [22] sends the X line, and video imaging device [23] transfers the X-ray line to luminous ray.
2. according to the video camera of the described control X-ray machine exposure of right 1, it is characterized in that described time-sequence control module [4] comprising: controller [6], counter [7], clock generator [8], fast shift sequential generation module [9], normally shift sequential generation module [10], read output signal generation module [11], substrate signal generating module [12], MUX [13]; X-ray machine control panel [20] is input to controller [6], and controller [6] outputs to counter [7], MUX [13], X lane controller [21], analog to digital conversion circuit [3] respectively; Clock generator [8] outputs to analog to digital conversion circuit [3] sum counter [7]; Computing module [5] is input to counter [7], counter [7] output to respectively controller [6], fast shift sequential generation module [9], normally shift sequential generation module [10], read output signal generation module [11], substrate signal generating module [12]; Shift sequential generation module [9] fast and normally shift sequential generation module [10] and all output to MUX [13]; MUX [13], read output signal generation module [11] and substrate signal generating module [12] all output to sensing circuit [2].
3. one kind is used the video camera of claim 1 to control the method that X-ray machine exposes, it is characterized in that, comprise in the double exposure of X-ray machine, CCD chip [1] exposed twice in the corresponding time, wherein the exposure first time of X-ray machine is that the pre-exposure time is less than 1 millisecond, exposure for the second time is called formal exposure, and the CCD chip [1] of the method can use interline transfer CCD and frame transfer CCD, and step is as follows:
1) operation X-ray machine control panel [20] is set X lane controller [21], provides bulb electric current mA according to irradiated site, and bulb voltage kVp produces X ray; Simultaneously, time-sequence control module [4] is sent out the substrate signal and is begun the exposure of CCD, and the exposure of X-ray machine and the exposure of CCD chip [1] this time is called pre-exposure;
2) process is less than after 1 millisecond time, and time-sequence control module [4] is sent out an exposure stop signal to X lane controller [21], and the control X-ray machine stops to produce X ray, and simultaneously, time-sequence control module [a 4] read output signal finishes CCD chip [1] exposure; Pre-exposure finishes;
3) time-sequence control module [4] sends quick transfer sequential to sensing circuit [2], sensing circuit [2] produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip [1], electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit [3], analog to digital conversion circuit [3] transfers the analog level of CCD chip [1] output to data image signal, produces the pre-exposure image;
4) computing module [5] is by the pre-exposure image, and formally the required time shutter of exposure feeds back to time-sequence control module [4] to calculate X-ray machine;
5) time-sequence control module [4] is sent out the exposure commencing signal to X lane controller [21], and X-ray machine begins formal exposure, and simultaneously, time-sequence control module [4] is sent out the substrate signal, formally exposure of CCD chip [1] beginning;
6) time-sequence control module [4] is sent out the end exposure signal to X lane controller [21] when the time shutter of setting arrives, and finishes the X-ray machine exposure; Simultaneously, time-sequence control module [4] is sent out read output signal, finishes CCD chip [1] current exposure;
7) time-sequence control module [4] sends normal transfer sequential to sensing circuit [2], sensing circuit [2] produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip [1], electric charge is under the driving of transfering clock in the CCD chip [1], output to analog to digital conversion circuit [3], analog to digital conversion circuit [3] transfers the analog level output of CCD chip [1] to data image signal, produces output image.
4. method according to claim 3 is characterized in that, described computing module [5] goes out X-ray machine by the pre-exposure image calculation, and formally the required time shutter of exposure may further comprise the steps:
1), obtains the feature gray scale of image from the pre-exposure image; The calculating of feature gray scale has following method:
I. calculate the average gray value of entire image;
Ii. on image, set 1 to 10 area-of-interest, calculate the average image gray-scale value of area-of-interest;
Iii. set the weighting coefficient of gradation of image around area-of-interest and its, calculate area-of-interest and the weighted mean of image around it;
2), calculate the formal time shutter of X-ray machine by formula (1):
T total = E m E pre * T pre - - - ( 1 )
Wherein, E mRepresent the average gray of CCD chip [1] output image when reaching maximum dynamic range, E PreRepresent the feature gray scale of pre-exposure image, T PreRepresent the time of X-ray machine pre-exposure; T TotalThe time of the formal exposure of expression X-ray machine.
5. one kind is used the video camera of claim 1 to control the method that X-ray machine exposes, it is characterized in that, comprise the single exposure of X-ray machine, the double exposure of CCD chip [1], the CCD chip [1] of the method can use interline transfer CCD and frame transfer CCD, may further comprise the steps:
1) operation X-ray machine control panel [20] is set X lane controller [21], and according to providing mA with irradiated site, kVp produces X ray; Simultaneously, time-sequence control module [a 4] substrate signal begins this exposure of CCD chip [1]; The exposure of CCD chip [1] this time is called short exposure;
2) process is less than after 1 millisecond time, and time-sequence control module [4] is sent out read output signal, finishes this integral time of CCD, finishes CCD and exposes; Short exposure finishes;
3) time-sequence control module [4] is exported different signals at the kind of CCD chip [1]; For interline transfer CCD, time-sequence control module [4] produces read output signal to sensing circuit [2], and sensing circuit [2] produces reads level, the electric charge of driving interline transfer CCD from pixel [15] to vertical transitions register [14]; For frame transfer CCD, time-sequence control module [4] produces and shifts sequential fast to sensing circuit [2], and sensing circuit [2] produces vertical transfer clock, and the driven CCD electric charge is transferred to memory block [20] from imaging area [19];
4) time-sequence control module [4] is sent out the integration that the substrate signal begins the formal exposure of CCD chip [1];
5) time-sequence control module [4] sends quick transfer sequential to sensing circuit [2], sensing circuit [2] produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip, electric charge is under the driving of transfering clock in the CCD chip [1], output to analog to digital conversion circuit [3], analog to digital conversion circuit [3] transfers the analog level output of CCD chip [1] to data image signal, produces the short exposure image;
6) computing module [5] is by the short exposure image, calculates this X-ray machine required time shutter of exposure to feed back to time-sequence control module [4];
7) time-sequence control module [4] is sent out the end exposure signal to X lane controller [21] when the time shutter of setting arrives, and finishes the X-ray machine exposure, and simultaneously, time-sequence control module [4] is sent out read output signal, finishes CCD chip [1] exposure;
8) time-sequence control module [4] sends normal transfer sequential to sensing circuit [2], sensing circuit [2] produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip [1], electric charge is under the driving of transfering clock in the CCD chip [1], output to analog to digital conversion circuit [3], analog to digital conversion circuit [3] transfers the analog level output of CCD chip [1] to data image signal, produces output image.
6. method according to claim 5 is characterized in that, computing module [5] comprises following step by the computing method of short exposure image calculation X-ray machine time shutter:
1), obtains the feature gray scale of image from the short exposure image; The computing method of feature gray scale are as follows:
I. calculate the average gray value of entire image;
Ii. on image, set 1 to 10 area-of-interest, calculate the average image gray-scale value of area-of-interest;
Iii. set the weighting coefficient of gradation of image around area-of-interest and its, calculate area-of-interest and the weighted mean of image around it;
2) by formula (2), calculate total time shutter of X-ray machine current exposure:
T total = E m E short * T short - - - ( 2 )
Wherein, E mRepresent the average gray of CCD chip [1] output image when reaching maximum dynamic range, E ShortRepresent the feature gray scale of short exposure image, T ShortWhen representative obtains the short exposure image, the time that X-ray machine has exposed; T TotalThe time that the total exposure of expression X-ray machine need be carried out.
7. one kind is used the video camera of claim 1 to control the method that X-ray machine exposes, it is characterized in that, read for twice that comprises CCD chip [1], effective duration of the read output signal in wherein reading for the first time is below 0.1 microsecond, read a little less than claiming this time to read as, the significant level duration of the read output signal in back claims to read as normally specifically to read between 5 to 100 microseconds; Claim this method to be weak reading method once, the CCD chip [1] of the method can use interline transfer CCD, and step is as follows:
1) operation X-ray machine control panel [20] is set X lane controller [21], provides mA according to irradiated site, and kVp produces X ray; Simultaneously, time-sequence control module [a 4] substrate signal begins this exposure of CCD chip [1];
2) after the time through the 1-5 millisecond, read tfi module [4] and send out the following read output signal of lasting 0.1 microsecond of a significant level, the part of electric charge below 1% transferred in the vertical transitions register [14] in driven CCD chip [1] pixel [15]; This is read a little less than reading and being called;
3) time-sequence control module [4] sends quick transfer sequential to sensing circuit [2], sensing circuit [2] produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip [1], electric charge is under the driving of transfering clock in the CCD chip [1], output to analog to digital conversion circuit [3], analog to digital conversion circuit [3] transfers the analog level output of CCD chip [1] to data image signal, reads image a little less than the generation;
4) computing module [5] is by the weak image of reading, and calculates this X-ray machine required time shutter of exposure to feed back to time-sequence control module [4];
5) time-sequence control module [4] is sent out the end exposure signal to X lane controller [21] when the time shutter of setting arrives, and finishes the X-ray machine exposure, and simultaneously, time-sequence control module [4] sends out normal read output signal, and end CCD chip [1] exposes;
6) time-sequence control module [4] sends normal transfer sequential to sensing circuit [2], sensing circuit [2] produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip [1], electric charge is under the driving of transfering clock among the CCD, output to analog to digital conversion circuit [3], analog to digital conversion circuit [3] transfers the analog level output of CCD to data image signal, produces output image.
8. method according to claim 7 is characterized in that, computing module [5] calculates the computing method of X-ray machine time shutter by the weak image of reading, and may further comprise the steps:
1), obtains the feature gray scale of image from the weak image of reading; The calculating of feature gray scale has following method:
I. calculate the average gray value of entire image;
II. on image, set 1 to 10 area-of-interest, calculate the average image gray-scale value of area-of-interest;
III. set the weighting coefficient of gradation of image around area-of-interest and its, calculate area-of-interest and the weighted mean of image around it;
2) by formula (3), (4) calculate this X-ray machine exposure required time:
E pre = τ t * E r - - - ( 3 )
T total = E m E pre * T pre - - - ( 4 )
Wherein, E PreA little less than obtaining, representative reads image constantly, the feature gray scale of CCD pixel [14]; The read output signal significant level duration during the τ representative is normally read; The read output signal significant level duration in reading a little less than the t representative; E rRead the feature gray scale of image a little less than the representative; E mThe average gray of output image when representing CCD to reach maximum dynamic range, T PreWhen reading image a little less than representative obtains, the time that X-ray machine has exposed; T TotalExpression total time shutter of X-ray machine.
9. the method for a video camera control X-ray machine exposure of using claim 1 is characterized in that, comprises that three times of CCD chip [1] are read, read a little less than wherein preceding read as for twice, after once for normally reading; Claim that this method is the weak reading method of secondary, the CCD chip [1] of the method can use interline transfer CCD, and step is as follows:
1) operation X-ray machine control panel [20] is set X lane controller [21], provides mA according to irradiated site, and kVp produces X ray, and simultaneously, video camera time-sequence control module [4] is sent out the substrate signal and begun this exposure of CCD chip [1];
2) time of process 1-5 millisecond, time-sequence control module [4] is sent out the following read output signal of significant level duration 0.1 microsecond, the middle part of electric charge below 1% that accumulates of CCD chip [1] pixel this moment [15] transferred in the vertical transitions register [14], and title is read a little less than this time reading as for the first time;
3) time-sequence control module [4] sends quick transfer sequential to sensing circuit [2], sensing circuit [2] produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip [1], electric charge is under the driving of transfering clock in the CCD chip [1], output to analog to digital conversion circuit [3], analog to digital conversion circuit [3] transfers the analog level output of CCD chip [1] to data image signal, reads image a little less than the generation for the first time;
4) pass through again the 1-5 millisecond time, reading tfi module, to send out a duration be the following read output signal of 0.1 microsecond, the middle part of electric charge below 1% that accumulates of CCD chip [1] pixel this moment [15] transferred in the vertical transitions register [14], and this is read a little less than reading and being called for the second time;
5) time-sequence control module [4] sends quick transfer sequential to sensing circuit [2], sensing circuit [2] produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip [1], electric charge is under the driving of transfering clock in the CCD chip [1], output to analog to digital conversion circuit [3], analog to digital conversion circuit [3] transfers the analog level output of CCD chip [1] to data image signal, reads image a little less than the generation for the second time;
6) video camera computing module [5] is read image a little less than twice, calculates total time shutter of X-ray machine to feed back to time-sequence control module [4];
7) time-sequence control module [4] is sent out the end exposure signal to X lane controller [21] when the time shutter of setting arrives, and finishes the X-ray machine exposure, and simultaneously, time-sequence control module [4] sends out normal read output signal, and end CCD chip [1] exposes;
8) time-sequence control module [4] sends normal transfer sequential to sensing circuit [2], sensing circuit [2] produces the vertical transfer clock and the horizontal transfer clock of driven CCD chip [1], electric charge is under the driving of transfering clock in the CCD chip [1], output to analog to digital conversion circuit [3], analog to digital conversion circuit [3] transfers the analog level output of CCD chip [1] to data image signal, produces output image.
10. method according to claim 9 is characterized in that, computing module [5] is read image a little less than by two width of cloth, calculates the method for X-ray machine time shutter, and step is as follows:
1), obtains the feature gray scale of image from the weak image of reading; The calculating of feature gray scale has following method:
I. calculate the average gray value of entire image;
Ii. on image, set 1 to 10 area-of-interest, calculate the average image gray-scale value of area-of-interest;
Iii. set the weighting coefficient of gradation of image around area-of-interest and its, calculate area-of-interest and the weighted mean of image around it;
2) by formula (5), (6), (7) calculate this X-ray machine exposure required time:
E 0 = τ t 0 * E r 0 - - - ( 5 )
E 1 = τ t 1 * E r 1 - - - ( 6 )
T total = ( E m - E 1 ) * ( T 1 - T 0 ) E 1 - E 0 + T 1 - - - ( 7 )
Wherein, E 0, E 1Represent respectively for the first time, read constantly the feature gray scale of CCD chip [1] pixel [15] a little less than the second time; t 0, t 1Represent for the first time the read output signal significant level duration in reading a little less than the second time respectively; The read output signal significant level duration during the τ representative is normally read; E R0, E R1Represent for the first time the feature gray scale of reading image a little less than the second time respectively; T 0, T 1Represent respectively for the first time, read the time shutter of X-ray machine constantly a little less than the second time; E mRepresent the average gray of CCD chip [1] output image when reaching maximum dynamic range; T TotalExpression total time shutter of X-ray machine.
CNB2006100418696A 2006-03-02 2006-03-02 Medical CCD camera and corresponding X-ray machine exposal control method Expired - Fee Related CN100561333C (en)

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CN103876762A (en) * 2012-11-06 2014-06-25 上海联影医疗科技有限公司 CT (computed tomography) bulb tube exposure control system and method
CN104735373A (en) * 2015-03-31 2015-06-24 中国科学院上海技术物理研究所 Method for reading data from frame transfer CCD high-frame-frequency window imaging area
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CN108770337A (en) * 2016-01-05 2018-11-06 Bae系统成像解决方案有限公司 The system and method for adjusting dental X-ray exposure
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CN102809869B (en) * 2011-06-02 2015-04-08 赵建国 X-ray exposure control method and device and X-ray exposure system
CN102809869A (en) * 2011-06-02 2012-12-05 赵建国 X-ray exposure control method and device and X-ray exposure system
CN103207592B (en) * 2012-01-11 2016-04-06 北京美智医疗科技有限公司 The program control rim brake device of medical x-ray machine, programmed control method and special-purpose member
CN103207592A (en) * 2012-01-11 2013-07-17 北京美智医疗科技有限公司 Program control hand brake device for medical X-ray machine, program control method and special parts
CN103876762A (en) * 2012-11-06 2014-06-25 上海联影医疗科技有限公司 CT (computed tomography) bulb tube exposure control system and method
CN103876762B (en) * 2012-11-06 2018-01-16 上海联影医疗科技有限公司 A kind of CT bulbs Exposure Control Module and method
CN103068135B (en) * 2013-01-06 2015-07-22 刘志宏 Time of exposure non-intervention measuring device and method of X-ray machine
CN103068135A (en) * 2013-01-06 2013-04-24 刘志宏 Time of exposure non-intervention measuring device and method of X-ray machine
CN104181805B (en) * 2014-07-07 2016-10-19 中国科学院长春光学精密机械与物理研究所 A kind of detection method of between-the-lens shutter closing time
CN104735373A (en) * 2015-03-31 2015-06-24 中国科学院上海技术物理研究所 Method for reading data from frame transfer CCD high-frame-frequency window imaging area
CN104735373B (en) * 2015-03-31 2017-09-26 中国科学院上海技术物理研究所 A kind of high frame frequency windowing imaging region data read methods of frame transfer CCD
CN108770337A (en) * 2016-01-05 2018-11-06 Bae系统成像解决方案有限公司 The system and method for adjusting dental X-ray exposure
CN108013887A (en) * 2016-10-28 2018-05-11 北京东软医疗设备有限公司 A kind of automatic exposure control method and device and auto exposure system
CN108013887B (en) * 2016-10-28 2020-09-11 北京东软医疗设备有限公司 Automatic exposure control method and device and automatic exposure system
CN110101399A (en) * 2018-02-01 2019-08-09 上海西门子医疗器械有限公司 Automatic exposure dosage adjusting method and system and storage medium for X-ray machine
CN111588398A (en) * 2020-05-26 2020-08-28 广东明峰医疗科技有限公司 CT exposure control method for effectively reducing invalid dose
CN111588398B (en) * 2020-05-26 2022-06-07 广东明峰医疗科技有限公司 CT exposure control method for effectively reducing invalid dose

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