CN103607205B - Signal processing method, apparatus and equipment - Google Patents
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Abstract
The invention discloses a signal processing method, apparatus and equipment. The signal processing method comprises the following steps that: an amplified electric pulse signal is obtained; analog-to-digital conversion is carried out on the amplified electric pulse signal so as to obtain a digital signal; sampling is carried out on the digital signal according to a preset time interval; whether a sampling result is larger than a preset threshold value is determined; and if so, the sampling result is stored; and two sampling results that are larger than the preset threshold value and are first to be stored in a cycle of decay are utilized to identify time information of the cycle of decay. According to the invention, the electric pulse signal is converted into the digital signal; time information identification processing is carried out on the sampling result of the digital signal; and the first two sampling results that are larger than the preset threshold value in the cycle of decay are used for identifying time information of the cycle of decay. Therefore, there is no need to use a time processing circuit for time identification process; the structure of a positron emission tomography (PET) system is simplified; and the system cost is lowered. Moreover, the digital signals can be transmitted in parallel; the transmission speed is fast; the time delay error is small; and the precision is high.
Description
Technical Field
The present invention relates to the field of computer technologies, and in particular, to a signal processing method, device, and apparatus.
Background
Positron Emission Tomography (PET) equipment is an advanced molecular imaging equipment in the medical field today. A radioactive nuclide is marked on the fluorodeoxyglucose to be used as a tracer, and after a positron released by the radioactive nuclide moves for a certain distance, the positron is annihilated with electrons with negative charges in the surrounding environment to generate a pair of gamma photons with equal energy and opposite directions.
Conventional PET equipment generally employs a closed-loop detector structure, and a detector loop is formed by assembling a plurality of detector modules. Each detector module is composed of a plurality of scintillation crystals and a Photomultiplier Tube (PMT). Gamma photons generated by annihilation are received by the detector ring, the gamma photons enter the scintillation crystal and then decay to generate optical pulse signals, and the PMT converts the optical pulse signals into electric pulse signals.
And after filtering and amplifying the electric pulse signal output by the PMT, carrying out signal processing on the electric pulse signal to obtain the time information of gamma photons. The time information is mainly used for determining the moment of receiving gamma photons, and further judging coincidence events. When the time difference of a pair of gamma photons reaching the detector is less than a preset time window (generally 8 to 12 ns), the pair of gamma photons is considered to be originated from the same positron annihilation event, namely, a coincidence event is generated, and the information generated by the pair of gamma photons is recorded; otherwise, the pair of gamma photons is considered as two single events and the resulting information is discarded. The electric pulse signals output by the PMT are analyzed to judge the time values received by a pair of gamma photons, judge whether a coincidence event occurs or not, and judge the position of a scintillation crystal receiving the gamma photons generating the coincidence event, so that the concentration distribution of the radioactive nuclide in a living body is obtained.
At present, a time processing circuit is mainly adopted for identifying time information of gamma photons, when the time processing circuit receives the gamma photons, a high-speed comparator in the circuit generates a time pulse, and a high-precision time measuring chip is used for measuring the time difference between the generated time pulse and the calibration time of a main clock, so that the time information of the received gamma photons is determined.
When the above method is used to process the electrical pulse signal output by the PMT, the following disadvantages are found by those skilled in the art:
the time processing circuit needs to adopt a high-speed comparator and a high-precision time measurement chip, the circuit cost is high, and the time processing circuit is needed to determine the time information of gamma photons in each channel of the PET system, so that the whole PET system is complex in structure and high in manufacturing cost.
Disclosure of Invention
In view of this, the present invention provides a signal processing method, apparatus and device, which convert the amplified electrical pulse signal into a digital signal, and perform identification processing on the sampling result of the digital signal without using a plurality of complex time processing circuits to respectively implement time information identification processing.
A method of signal processing, the method comprising:
acquiring an amplified electric pulse signal, wherein the electric pulse signal is obtained by performing photoelectric conversion on an optical pulse signal;
performing analog-to-digital conversion on the amplified electric pulse signal to obtain a digital signal;
sampling the digital signal according to a preset time interval;
judging whether the sampling result is larger than a preset threshold value or not, and if so, storing the sampling result;
and identifying a time information of a decay period by using two sampling results which are firstly stored in the decay period and are larger than a preset threshold value.
Optionally, the method further includes:
one energy information of one decay period is identified using all the stored samples of the decay period.
Optionally, the one energy information for identifying a decay period by using all the stored sampling results in the decay period comprises:
summing all sampling results in a decay period to obtain a sampling sum, and taking the product of the sampling sum and a time interval as energy information of the decay period;
or,
the product of each sample stored in a decay period and the time interval is used as a sub-energy value, and each sub-energy value is summed to be used as energy information in a decay period.
Optionally, the identifying a time information of a decay cycle by using two sampling results which are stored first in the decay cycle and are greater than a preset threshold value includes:
calculating the ratio of the difference value between two sampling moments which are stored firstly and are greater than a preset threshold value and time information as a first ratio;
calculating the ratio of two sub-energy values of two times of sampling which are stored firstly and are larger than a preset threshold value as a second ratio;
the difference value between two sampling moments which are stored firstly and are greater than a preset threshold value is a preset time interval;
calculating the difference value between the first sampling moment and the time information according to a preset time interval by using the first ratio equal to the second ratio as an initial time period;
calculating the difference value between the sampling time and the calibration time of the first sampling result as a total time period;
the difference between the total time period and the start time period is calculated as a time information of the decay period.
Optionally, the acquiring the amplified electrical pulse signal includes:
acquiring a pre-amplified electric pulse signal;
or,
and acquiring the electric pulse signals after pre-amplification and variable gain amplification.
A signal processing apparatus, the apparatus comprising:
the signal acquisition unit is used for acquiring the amplified electric pulse signals, and the electric pulse signals are obtained by performing photoelectric conversion on the electric pulse signals;
the analog-to-digital conversion unit is used for performing analog-to-digital conversion on the amplified electric pulse signal to obtain a digital signal;
the sampling unit is used for sampling the digital signal according to a preset time interval;
the judging unit is used for judging whether the sampling result is larger than a preset threshold value or not, and if so, storing the sampling result;
and the time identification unit is used for identifying time information of the decay period by utilizing two sampling results which are firstly stored in the decay period and are larger than a preset threshold value.
Optionally, the apparatus further comprises:
and the energy identification unit is used for identifying energy information of the decay period by using all the stored sampling results in the decay period.
Optionally, the energy identification unit includes:
the first energy identification subunit is used for summing all sampling results in a decay period to obtain a sampling sum, and taking the product of the sampling sum and a time interval as energy information of the decay period;
or,
and a second energy identifying subunit, for taking the product of each sampling result stored in a decay period and the time interval as a sub-energy value, and summing each sub-energy value as an energy information in a decay period.
Optionally, the time identification unit includes:
the first calculating subunit is used for calculating a ratio of a difference value between two firstly stored sampling moments which are greater than a preset threshold value and time information, and taking the ratio as a first ratio;
the second calculating subunit is used for calculating the ratio of two sub-energy values of two times of sampling which are stored firstly and are larger than a preset threshold value as a second ratio;
the third calculation subunit is used for firstly storing a difference value between two sampling moments which are greater than a preset threshold value and are used for two times as a preset time interval;
the fourth calculating subunit is configured to calculate, according to a preset time interval, a difference between the first sampling time and the time information as an initial time period by using that the first ratio is equal to the second ratio;
the fifth calculating subunit is used for calculating the difference value between the sampling time and the calibration time of the first sampling result as a total time period;
and the sixth calculating subunit is used for calculating the difference value between the total time period and the starting time period as one time information of the decay period.
Optionally, the signal acquiring unit includes:
the first signal acquisition subunit is used for acquiring the pre-amplified electric pulse signal;
or,
and the second signal acquisition subunit is used for acquiring the electric pulse signals after the pre-amplification and the variable gain amplification.
A signal processing apparatus, the apparatus comprising:
the photomultiplier, the amplifying circuit, the analog-to-digital conversion chip and the programmable logic device are connected in sequence;
the photomultiplier is used for converting the received optical pulse signals into electric pulse signals;
an amplifying circuit for amplifying the electric pulse signal;
the analog-to-digital conversion chip is used for performing analog-to-digital conversion on the amplified electric pulse signal to obtain a digital signal;
the programmable logic device is used for sampling the digital signal according to a preset time interval; judging whether the sampling result is larger than a preset threshold value or not, and if so, storing the sampling result; the stored sampling results are subjected to a time detection process and/or an energy detection process during a decay period.
From the above, the present invention has the following advantages:
the invention discloses a signal processing method, a device and equipment, wherein amplified electric pulse signals are obtained, and the electric pulse signals are obtained by performing photoelectric conversion on the electric pulse signals; performing analog-to-digital conversion on the amplified electric pulse signal to obtain a digital signal; sampling the digital signal according to a preset time interval; judging whether the sampling result is larger than a preset threshold value or not, and if so, storing the sampling result; the method comprises the steps of identifying time information of a decay period by utilizing two sampling results which are firstly stored and are larger than a preset threshold value in the decay period, converting received optical pulse signals into electric pulse signals and then into digital signals, carrying out time information identification processing on the sampling results of the digital signals, identifying time information of the decay period by utilizing two sampling results which are firstly stored and are larger than the preset threshold value in the decay period, and not needing to adopt a time processing circuit to carry out time identification processing.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow chart of a signal processing method according to an embodiment of the present invention;
FIG. 2 is a diagram illustrating a digital signal sampling result according to the present invention;
FIG. 3 is a flowchart of a signal processing method according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a method of obtaining decay cycle time information t according to the present invention;
FIG. 5 is a schematic diagram of a signal processing apparatus according to a third embodiment of the present invention;
FIG. 6 is a diagram illustrating a fourth exemplary embodiment of a signal processing apparatus according to the present invention;
fig. 7 is a schematic structural diagram of a signal processing apparatus according to a fifth embodiment of the present invention.
Detailed Description
The invention discloses a signal processing method, a device and equipment, which convert an amplified electric pulse signal into a digital signal, and carry out time information identification processing on a digital signal sampling result, thereby simplifying the system structure and reducing the system cost.
The following describes embodiments of the present invention in detail with reference to the accompanying drawings.
Example one
Fig. 1 is a flow chart of an embodiment of a signal processing method according to the present invention, the method includes:
step 101: and acquiring an amplified electric pulse signal, wherein the electric pulse signal is obtained by performing photoelectric conversion on the optical pulse signal.
Gamma photons generated by positron annihilation are received by a crystal on the detector, the gamma photons decay in the crystal to generate a light pulse signal of visible light, and the light pulse signal is converted into an electric pulse signal by a Photomultiplier Tube (PMT) and output. Gamma photons are in different crystals with different decay periods, for example: in bismuth germanate (Bi)4Ge3O12BGO) crystal, the decay period of the gamma photon is 300 ns.
The visible light generated by gamma photon decay is very weak and cannot be detected, although the visible light is amplified after being received by the PMT, the amplified signal is still not enough to be directly detected, and the electric pulse signal amplified and converted by the PMT needs to be further amplified for detection.
Optionally, the acquiring the amplified electrical pulse signal includes two possible embodiments:
a first possible implementation:
and acquiring the electric pulse signal after pre-amplification.
The pre-amplification can amplify the electrical pulse signal to a range where it can be directly detected.
A second possible implementation:
and acquiring the electric pulse signals after pre-amplification and variable gain amplification.
The electric pulse signal is not only pre-amplified, but also amplified with variable gain, so that the noise in the electric pulse signal can be effectively reduced.
Step 102: and performing analog-to-digital conversion on the amplified electric pulse signal to obtain a digital signal.
The amplified electrical pulse signal is converted into a Digital signal by an Analog-to-Digital Converter (ADC) or an Analog-to-Digital Converter chip.
Step 103: and sampling the digital signal according to a preset time interval.
And sampling the converted digital signal by adopting a Programmable Gate Array (FPGA) according to a preset time interval, wherein the sampling frequency cannot be less than 40 MHz. Taking the BGO crystal as an example, the decay period of gamma photons is 300ns, the sampling frequency of FPGA is 100M, and 30 times can be sampled every time one gamma photon is received.
Step 104: judging whether the sampling result is larger than a preset threshold value or not, if so, executing the step 105; if not, step 107 is performed.
Step 105: and storing the sampling result.
Presetting a preset threshold value in the FPGA, when the sampling value is larger than the preset threshold value, indicating that an optical pulse signal generated by gamma photons is received, namely an event is received, and storing the sampling result.
Step 106: and identifying a time information of a decay period by using two sampling results which are firstly stored in the decay period and are larger than a preset threshold value.
After an optical pulse signal generated by one gamma photon decay period is converted into an electric pulse signal, a digital signal obtained by analog-to-digital conversion can be sampled according to a preset time interval, and a plurality of sampling results can be acquired. Since the energy release process is an increase and decrease process when the gamma photons decay, the value of the sampling result is also increased and decreased. From the first sampling result larger than the preset threshold value to the last sampling result larger than the preset threshold value, all the continuous sampling results in the period are the sampling results stored in one decay period, as shown in fig. 2, a total of 23 sampling results are stored in one decay period, and the values of the sampling results are increased and then decreased according to the sampling sequence.
And (3) carrying out time identification processing on the sampling result:
and obtaining specific time information of gamma photon decay according to two sampling results which are firstly stored in a decay period and are larger than a preset threshold value. Outputting the obtained time information to a coincidence processor, carrying out coincidence time judgment on two recently received time information sent by different signal processing devices by the coincidence processor, and when the time difference between the two time information is smaller than a preset time window (usually 8-12 ns), considering that the two time information generate a coincidence event and recording the coincidence event; and if the time difference between the two pieces of time information is greater than a preset time window, the two pieces of time information are two separate events respectively, and the time information is discarded. And providing effective data basis for subsequent processing according to the times of the coincidence events recorded by the coincidence processor.
Step 107: the sampling result is discarded.
And when the sampling value is smaller than the preset threshold value, the current sampling value can be considered as noise, and the sampling result is discarded.
From the above, the present invention has the following advantages:
the invention discloses a signal processing method, a device and equipment, wherein amplified electric pulse signals are obtained, and the electric pulse signals are obtained by performing photoelectric conversion on the electric pulse signals; performing analog-to-digital conversion on the amplified electric pulse signal to obtain a digital signal; sampling the digital signal according to a preset time interval; judging whether the sampling result is larger than a preset threshold value or not, and if so, storing the sampling result; the method comprises the steps of identifying time information of a decay period by utilizing two sampling results which are firstly stored and are larger than a preset threshold value in the decay period, converting received optical pulse signals into electric pulse signals and then into digital signals, carrying out time information identification processing on the sampling results of the digital signals, identifying time information of the decay period by utilizing two sampling results which are firstly stored and are larger than the preset threshold value in the decay period, and not needing to adopt a time processing circuit to carry out time identification processing.
Example two
Fig. 3 is a flowchart of an embodiment of a signal processing method according to the present invention, wherein compared with the first embodiment, the method further includes an energy identification process, and the method includes:
step 301: and acquiring an amplified electric pulse signal, wherein the electric pulse signal is obtained by performing photoelectric conversion on the optical pulse signal.
Step 302: and performing analog-to-digital conversion on the amplified electric pulse signal to obtain a digital signal.
Step 303: and sampling the digital signal according to a preset time interval.
Step 304: judging whether the sampling result is larger than a preset threshold value, if so, executing a step 305; if not, step 308 is performed.
Step 305: and storing the sampling result.
Steps 301 to 305 are similar to the embodiments, and refer to the description of the first embodiment, which is not repeated herein.
Step 306: and identifying a time information of a decay period by using two sampling results which are firstly stored in the decay period and are larger than a preset threshold value.
Optionally, the identifying a time information of a decay cycle by using two sampling results which are stored first in the decay cycle and are greater than a preset threshold value includes:
calculating the ratio of the difference value between two sampling moments which are stored firstly and are greater than a preset threshold value and time information as a first ratio;
calculating the ratio of two sub-energy values of two times of sampling which are stored firstly and are larger than a preset threshold value as a second ratio;
the difference value between two sampling moments which are stored firstly and are greater than a preset threshold value is a preset time interval;
calculating the difference value between the first sampling moment and the time information according to a preset time interval by using the first ratio equal to the second ratio as an initial time period;
calculating the difference value between the sampling time and the calibration time of the first sampling result as a total time period;
the difference between the total time period and the start time period is calculated as a time information of the decay period.
Alternatively, as shown in fig. 4, a time information identifying the decay period can also be calculated using equation (1):
wherein m is the number of preset time intervals included between the sampling time and the calibration time of the first sampling result, E1Is the sub-energy value of the first sampling result, E2Is the sub-energy value of the second sampling result, t0T is time information for a preset time interval.
Step 307: one energy information of one decay period is identified using all the stored samples of the decay period.
As shown in fig. 2, the product of each sampling result and the sampling time interval is used as a sub-energy value, and the energy information of one decay period is obtained by summing all 23 sub-energy values.
Alternatively, there are two possible implementations of the identification of one energy information of a decay period using all the stored samples of this decay period:
a first possible implementation: the product of each sample stored in a decay period and the time interval is used as a sub-energy value, and each sub-energy value is summed to be used as energy information in a decay period.
Obtaining energy information E according to equation (2):
wherein h isiFor the height of each sample result, t0N is the number of sampling results for a preset time interval.
A second possible implementation: and summing all sampling results in a decay period to obtain a sampling sum, and taking the product of the sampling sum and the time interval as energy information of the decay period.
Obtaining energy information E according to equation (3):
wherein h isiFor the height of each sample result, t0N is the number of sampling results for a preset time interval.
After the energy identification processing is carried out on the sampling result stored in one decay period, the obtained energy information can provide reliable data basis for the subsequent processing:
the energy information produced by a gamma photon decay period, which is the energy information produced by the decay of gamma photons received by a PMT, is calculated from the stored samples during a decay period.
One detector is a matrix of 11 by 11 crystals, each followed by 2 PMTs that receive the visible light produced by the decay of gamma photons from the crystals. The four PMTs form a four-quadrant receiving region, and the number of visible light generated by each PMT receiving gamma photon decay is different, and the electric pulse signals generated in each PMT are also different.
In a decay period, the energy information obtained by processing the electric pulse signals converted by each PMT during the decay of gamma photons is analyzed, and because the energy information obtained by the subsequent processing of the electric pulse signals output by the PMT is different in size, the position with the strongest energy released during the decay can be obtained through analysis, namely the specific position of a crystal receiving the gamma photons on the detector, and the position of the gamma photons generated by the positron decay can be further known, so that the concentration distribution of the radioactive nuclides in a living body can be obtained.
It should be noted here that the execution order of step 306 and step 307 is not limited, and step 307 may be executed first, step 306 is executed, or only one of the steps may be executed. Step 308: the sampling result is discarded.
EXAMPLE III
Fig. 5 is a schematic diagram of a third structure of a signal processing apparatus according to an embodiment of the present invention, which is an apparatus corresponding to the method according to the first embodiment of the present invention, and the apparatus includes:
the signal acquiring unit 501 is configured to acquire an amplified electrical pulse signal, where the electrical pulse signal is obtained by performing photoelectric conversion on an optical pulse signal.
Optionally, the signal acquiring unit 501 includes:
the first signal acquisition subunit is used for acquiring the pre-amplified electric pulse signal;
or,
and the second signal acquisition subunit is used for acquiring the electric pulse signals after the pre-amplification and the variable gain amplification.
An analog-to-digital conversion unit 502, configured to perform analog-to-digital conversion on the amplified electrical pulse signal to obtain a digital signal.
A sampling unit 503, configured to sample the digital signal at preset time intervals.
The determining unit 504 is configured to determine whether the sampling result is greater than a preset threshold, and if so, store the sampling result.
The time identification unit 505 is configured to identify a time information of a decay period by using two sampling results which are stored first in the decay period and are greater than a preset threshold value.
Example four
Fig. 6 is a schematic diagram of a fourth structure of a signal processing apparatus according to an embodiment of the present invention, which is an apparatus corresponding to the method according to the second embodiment, and the apparatus includes:
the signal acquiring unit 501 is configured to acquire an amplified electrical pulse signal, where the electrical pulse signal is obtained by performing photoelectric conversion on an optical pulse signal.
An analog-to-digital conversion unit 502, configured to perform analog-to-digital conversion on the amplified electrical pulse signal to obtain a digital signal.
A sampling unit 503, configured to sample the digital signal at preset time intervals.
The determining unit 504 is configured to determine whether the sampling result is greater than a preset threshold, and if so, store the sampling result.
The time identification unit 505 is configured to identify a time information of a decay period by using two sampling results which are stored first in the decay period and are greater than a preset threshold value.
Optionally, the time identification unit 505 includes:
the first calculating subunit is used for calculating a ratio of a difference value between two firstly stored sampling moments which are greater than a preset threshold value and time information, and taking the ratio as a first ratio;
the second calculating subunit is used for calculating the ratio of two sub-energy values of two times of sampling which are stored firstly and are larger than a preset threshold value as a second ratio;
the third calculation subunit is used for firstly storing a difference value between two sampling moments which are greater than a preset threshold value and are used for two times as a preset time interval;
the fourth calculating subunit is configured to calculate, according to a preset time interval, a difference between the first sampling time and the time information as an initial time period by using that the first ratio is equal to the second ratio;
the fifth calculating subunit is used for calculating the difference value between the sampling time and the calibration time of the first sampling result as a total time period;
and the sixth calculating subunit is used for calculating the difference value between the total time period and the starting time period as one time information of the decay period.
Optionally, the time identification unit 505 includes:
the time identification subunit is used for calculating and identifying a piece of time information of the decay period by using two sampling results which are firstly stored in the decay period and are larger than a preset threshold value and adopting the following formula:
wherein m is the number of preset time intervals included between the sampling time and the calibration time of the first sampling result, E1Is the sub-energy value of the first sampling result, E2Is the sub-energy value of the second sampling result, t0T is time information for a preset time interval.
An energy identification unit 601 for identifying an energy information of a decay period by using all the stored samples in the decay period.
Optionally, the energy identification unit 601 includes:
the first energy identification subunit is used for summing all sampling results in a decay period to obtain a sampling sum, and taking the product of the sampling sum and a time interval as energy information of the decay period;
or,
and a second energy identifying subunit, for taking the product of each sampling result stored in a decay period and the time interval as a sub-energy value, and summing each sub-energy value as an energy information in a decay period.
EXAMPLE five
Fig. 7 is a schematic structural diagram of a fifth embodiment of a signal processing apparatus according to the present invention, where the apparatus includes:
the photomultiplier 701, the amplifier circuit 702, the analog-to-digital conversion chip 703, and the programmable logic device 704 are connected in sequence.
And a photomultiplier 701 for converting the received optical pulse signal into an electrical pulse signal.
An amplifying circuit 702 for amplifying the electrical pulse signal.
The analog-to-digital conversion chip 703 is configured to perform analog-to-digital conversion on the amplified electrical pulse signal to obtain a digital signal.
The programmable logic device 704 is used for sampling the digital signal according to a preset time interval; judging whether the sampling result is larger than a preset threshold value or not, and if so, storing the sampling result; the stored sampling results are subjected to a time detection process and/or an energy detection process during a decay period.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (9)
1. A method of signal processing, the method comprising:
acquiring an amplified electric pulse signal, wherein the electric pulse signal is obtained by performing photoelectric conversion on an optical pulse signal;
performing analog-to-digital conversion on the amplified electric pulse signal to obtain a digital signal;
sampling the digital signal according to a preset time interval;
judging whether the sampling result is larger than a preset threshold value or not, and if so, storing the sampling result;
identifying a time information of a decay period by using two sampling results which are firstly stored in the decay period and are larger than a preset threshold value;
the time information for identifying the decay period by using the two sampling results which are firstly stored in the decay period and are larger than the preset threshold value comprises the following steps:
calculating the ratio of the difference value between two sampling moments which are stored firstly and are greater than a preset threshold value and time information as a first ratio;
calculating the ratio of two sub-energy values of two times of sampling which are stored firstly and are larger than a preset threshold value as a second ratio;
the difference value between two sampling moments which are stored firstly and are greater than a preset threshold value is a preset time interval;
calculating the difference value between the first sampling moment and the time information according to a preset time interval by using the first ratio equal to the second ratio as an initial time period;
calculating the difference value between the sampling time and the calibration time of the first sampling result as a total time period;
the difference between the total time period and the start time period is calculated as a time information of the decay period.
2. The method of claim 1, further comprising:
one energy information of one decay period is identified using all the stored samples of the decay period.
3. The method of claim 2, wherein identifying an energy information of a decay period using all stored samples within the decay period comprises:
summing all sampling results in a decay period to obtain a sampling sum, and taking the product of the sampling sum and a time interval as energy information of the decay period;
or,
the product of each sample stored in a decay period and the time interval is used as a sub-energy value, and each sub-energy value is summed to be used as energy information in a decay period.
4. The method of any of claims 1-3, wherein said acquiring amplified electrical pulse signals comprises:
acquiring a pre-amplified electric pulse signal;
or,
and acquiring the electric pulse signals after pre-amplification and variable gain amplification.
5. A signal processing apparatus, characterized in that the apparatus comprises:
the signal acquisition unit is used for acquiring the amplified electric pulse signals, and the electric pulse signals are obtained by performing photoelectric conversion on the electric pulse signals;
the analog-to-digital conversion unit is used for performing analog-to-digital conversion on the amplified electric pulse signal to obtain a digital signal;
the sampling unit is used for sampling the digital signal according to a preset time interval;
the judging unit is used for judging whether the sampling result is larger than a preset threshold value or not, and if so, storing the sampling result;
the time identification unit is used for identifying time information of a decay period by utilizing two sampling results which are firstly stored in the decay period and are larger than a preset threshold value;
the time recognition unit includes:
the first calculating subunit is used for calculating a ratio of a difference value between two firstly stored sampling moments which are greater than a preset threshold value and time information, and taking the ratio as a first ratio;
the second calculating subunit is used for calculating the ratio of two sub-energy values of two times of sampling which are stored firstly and are larger than a preset threshold value as a second ratio;
the third calculation subunit is used for firstly storing a difference value between two sampling moments which are greater than a preset threshold value and are used for two times as a preset time interval;
the fourth calculating subunit is configured to calculate, according to a preset time interval, a difference between the first sampling time and the time information as an initial time period by using that the first ratio is equal to the second ratio;
the fifth calculating subunit is used for calculating the difference value between the sampling time and the calibration time of the first sampling result as a total time period;
and the sixth calculating subunit is used for calculating the difference value between the total time period and the starting time period as one time information of the decay period.
6. The apparatus of claim 5, further comprising:
and the energy identification unit is used for identifying energy information of the decay period by using all the stored sampling results in the decay period.
7. The apparatus of claim 6, wherein the energy recognition unit comprises:
the first energy identification subunit is used for summing all sampling results in a decay period to obtain a sampling sum, and taking the product of the sampling sum and a time interval as energy information of the decay period;
or,
and a second energy identifying subunit, for taking the product of each sampling result stored in a decay period and the time interval as a sub-energy value, and summing each sub-energy value as an energy information in a decay period.
8. The apparatus according to any one of claims 5 to 7, wherein the signal acquisition unit comprises:
the first signal acquisition subunit is used for acquiring the pre-amplified electric pulse signal;
or,
and the second signal acquisition subunit is used for acquiring the electric pulse signals after the pre-amplification and the variable gain amplification.
9. A signal processing apparatus, characterized in that the apparatus comprises:
the photomultiplier, the amplifying circuit, the analog-to-digital conversion chip and the programmable logic device are connected in sequence;
the photomultiplier is used for converting the received optical pulse signals into electric pulse signals;
an amplifying circuit for amplifying the electric pulse signal;
the analog-to-digital conversion chip is used for performing analog-to-digital conversion on the amplified electric pulse signal to obtain a digital signal;
the programmable logic device is used for sampling the digital signal according to a preset time interval; judging whether the sampling result is larger than a preset threshold value or not, and if so, storing the sampling result; performing time identification processing and/or energy identification processing on the sampling result stored in one decay period;
identifying a time information of a decay cycle includes:
calculating the ratio of the difference value between two sampling moments which are stored firstly and are greater than a preset threshold value and time information as a first ratio;
calculating the ratio of two sub-energy values of two times of sampling which are stored firstly and are larger than a preset threshold value as a second ratio;
the difference value between two sampling moments which are stored firstly and are greater than a preset threshold value is a preset time interval;
calculating the difference value between the first sampling moment and the time information according to a preset time interval by using the first ratio equal to the second ratio as an initial time period;
calculating the difference value between the sampling time and the calibration time of the first sampling result as a total time period;
the difference between the total time period and the start time period is calculated as a time information of the decay period.
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| CN107981877B (en) * | 2016-10-27 | 2021-01-05 | 北京东软医疗设备有限公司 | Sampling method and sampling device of scanning equipment |
| CN109270490A (en) * | 2018-09-30 | 2019-01-25 | 成都精位科技有限公司 | Positioning signal processing method and processing device |
| CN109330598A (en) * | 2018-10-31 | 2019-02-15 | 上海健康医学院 | A real-time counting detector for positron nuclides based on the detection principle |
| CN109884684B (en) * | 2019-01-10 | 2020-09-15 | 中国科学院高能物理研究所 | Electronic data processing method and system for performance test of PET scintillation crystal |
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