Filtering method and circuit for video signal, and computer-readable storage medium

Abstract

The present invention relates to a filtering method and circuit for a video signal, and a computer-readable storage medium in the technical field of video signal processing. The method comprises the following steps: receiving a video signal, and performing high‑low frequency detection on the video signal to output a detection result; performing first synchronous delay processing on the video signal on the basis of the high-low frequency detection to obtain a first synchronously delayed signal; on the basis of the detection result, performing selective filtering processing on the first synchronously delayed signal to obtain a filtered signal, and on the basis of a filter register delay, performing second synchronous delay processing on the first synchronously delayed signal to obtain a second synchronously delayed signal; and on the basis of the detection result, selectively outputting the filtered signal and the second synchronously delayed signal to obtain a filtered output signal. The present invention solves the problem of increased circuit power consumption of existing filtering circuits caused by performing a filtering operation on both high-frequency signals and low-frequency signals during the filtering operation of video signals.

Description

A video signal filtering method, circuit, and computer-readable storage medium Technical Field

[0001] This invention relates to the field of video signal processing technology, and more specifically to a video signal filtering method, circuit, and computer-readable storage medium. Background Technology

[0002] Analog video signals contain luminance signals, chrominance signals, color sync signals, and composite sync signals. Luminance signals and composite sync signals are low-frequency signal components, while chrominance signals and color sync signals are high-frequency signal components. In digital circuits that decode analog video signals, various filtering operations are required to process the high-frequency components in order to separate the luminance signals, chrominance signals, color sync signals, and composite sync signals.

[0003] In digital circuits, filter circuits typically consist of a large number of multiply-accumulate structures and operate continuously after the circuit is powered on. Existing digital filters usually perform filtering operations on both high-frequency and low-frequency signals. However, in practice, filtering is unnecessary for the low-frequency signal range. If filtering is performed, the circuit will generate power consumption due to signal inversion in that range, thereby increasing the circuit's power consumption. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a video signal filtering method, circuit, and computer-readable storage medium. It solves the problem that existing filtering circuits increase power consumption when filtering both high-frequency and low-frequency signals.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A method for filtering video signals, comprising the following steps:

[0007] Receive a video signal, perform high and low frequency detection on the video signal, and output the detection result, wherein outputting the detection result includes marking each sample point interval of the video signal as a high frequency signal or a low frequency signal;

[0008] Based on the high and low frequency detection, the video signal is subjected to the first synchronization delay processing to obtain synchronization delay signal one;

[0009] Based on the detection results, the first synchronization delay signal is selectively filtered to obtain a filtered signal. At the same time, based on the filter register delay, the first synchronization delay signal is subjected to a second synchronization delay to obtain the second synchronization delay signal.

[0010] Based on the detection results, the filtered signal and the second synchronization delay signal are selectively output to obtain the filtered output signal.

[0011] Optionally, the high and low frequency detection includes the following steps:

[0012] Set a high-frequency signal threshold and calculate the amplitude of the signal change between each current sample signal and the previous sample signal in the video signal;

[0013] Based on the signal change amplitude and the high-frequency signal threshold, the signal type of each current sample signal is determined, and high-frequency signal counting is performed based on the signal type of each current sample signal.

[0014] Based on the counting results of high-frequency signals, the signal type of the sample interval is obtained, wherein the sample interval is a signal interval formed by multiple consecutive sample signals, and the length of the sample interval is the minimum interval length where high-frequency signals exist in the video signal.

[0015] Optionally, determine the signal type of each current sample signal and perform high-frequency signal counting based on the signal type of each current sample signal, including the following steps:

[0016] Determine whether the amplitude of each signal change is greater than or equal to the high-frequency signal threshold;

[0017] If yes, then the signal type of the current sample signal corresponding to the change in amplitude of the signal is determined to be a high-frequency signal; otherwise, the signal type of the current sample signal corresponding to the change in amplitude of the signal is determined to be a low-frequency signal.

[0018] When the signal type is a high-frequency signal, determine whether the high-frequency signal count value is equal to the maximum count threshold. If yes, the high-frequency signal is not counted; otherwise, the high-frequency signal count is incremented by "1".

[0019] When the signal type is a low-frequency signal, determine whether the high-frequency signal count value is equal to the minimum count threshold. If yes, the high-frequency signal is not counted; if no, the high-frequency signal count is decremented by "1". The initial count value is the minimum count threshold and is the same as the number of samples in the sample interval.

[0020] Optionally, based on the counting results of high-frequency signal counting, the signal type of the sample interval is obtained, including the following steps:

[0021] The counting results corresponding to each sample interval of the video signal are compared with zero-crossing. If the high-frequency signal count value in the counting result is greater than zero, the signal type of the sample interval is determined to be a high-frequency signal; otherwise, it is a low-frequency signal.

[0022] Optionally, during the first synchronization delay processing, the video signal is delayed based on the delay generated by the high and low frequency detection register and the delay generated by the logic detection cycle of high and low frequency detection.

[0023] Optionally, the selective filtering process includes the following steps:

[0024] In the synchronous delay signal one, the signal region corresponding to the sample interval marked as high-frequency signal is filtered;

[0025] In the synchronous delay signal, the signal region corresponding to the sampling interval marked as low frequency signal is not filtered.

[0026] Optionally, during the second synchronization delay processing, the synchronization delay signal one is delayed based on the delay generated by the register in the filter.

[0027] Optionally, selectively outputting filtered output signals includes the following steps:

[0028] When the sampling interval is a high-frequency signal, the region of the filtered signal corresponding to the sampling interval is selected as the output.

[0029] When the sampling interval is a low-frequency signal, the region of the synchronous delay signal two corresponding to the sampling interval is selected as the output.

[0030] A video signal filtering circuit, wherein the video signal filtering circuit performs the video signal filtering method described in any one of the above claims, includes a high-low frequency detection circuit, a first delay synchronization circuit, a filtering circuit, a second delay synchronization circuit, a first selector, and a second selector. The output terminal of the high-low frequency detection circuit is connected to the input terminals of the first selector and the second selector, respectively. The output terminal of the first delay synchronization circuit is connected to the input terminals of the filtering circuit and the second delay synchronization circuit, respectively. The output terminals of the filtering circuit and the second delay synchronization circuit are both connected to the input terminal of the second selector. The output terminal of the first selector is connected to the input terminal of the filtering circuit.

[0031] The high and low frequency detection circuit is used to receive the input clock and video signal, perform high and low frequency detection on the video signal, and output the detection result;

[0032] The first selector is used to output a digital signal based on the output detection result;

[0033] The delay synchronization circuit one is used to perform the first synchronization delay processing on the video signal based on high and low frequency detection to obtain the first synchronization delay signal;

[0034] The filtering circuit is used to selectively filter the synchronous delay signal 1 according to the detection result to obtain the filtered signal;

[0035] The second delay synchronization circuit is used to perform a second synchronization delay processing on the first synchronization delay signal according to the filter register delay, so as to obtain the second synchronization delay signal.

[0036] The second selector is used to selectively output the filtered signal and the synchronization delay signal based on the detection result, so as to obtain a filtered output signal.

[0037] A computer-readable storage medium storing a computer program, which, when executed by a processor, performs the video signal filtering method described in any one of the preceding claims.

[0038] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0039] By performing high and low frequency detection on the video signal, the video signal is marked as a high-frequency signal or a low-frequency signal in the form of multiple sample intervals, so that the video signal can be selected and filtered in the subsequent process, thereby reducing the unnecessary circuit power consumption caused by filtering low-frequency signals.

[0040] The first synchronization delay process aligns the synchronization delay signal with the high-frequency and low-frequency signals in the video signal after high and low frequency detection. This ensures that during selective filtering, the high-frequency and low-frequency signals identified in the video signal can be accurately selected for filtering, thus ensuring the accuracy of the filtering results.

[0041] The second synchronization delay process aligns the second synchronization delay signal with the filter signal, thus facilitating the obtaining of an accurate filtered output signal in the final output. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 is a flowchart of a video signal filtering method proposed in this embodiment 1;

[0044] Figure 2 is a flowchart of the high and low frequency detection proposed in this embodiment 1;

[0045] Figure 3 shows the simulated waveforms of each signal obtained by the video signal filtering method according to Embodiment 1.

[0046] Figure 4 shows a video signal filtering circuit proposed in this embodiment 2. Detailed Implementation

[0047] The present invention will be further described in detail below with reference to the embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0048] Example 1

[0049] As shown in Figure 1, a video signal filtering method includes the following steps: S100, receiving a video signal and performing high and low frequency detection on the video signal, and outputting the detection result. The output detection result includes marking each sample interval of the video signal as a high-frequency signal or a low-frequency signal. By judging the high and low frequency signals of the video signal, the video signal is marked as a high-frequency signal or a low-frequency signal in the form of multiple sample intervals for subsequent filtering of high-frequency signals, while low-frequency signals are not filtered, thereby reducing the unnecessary circuit power consumption caused by filtering low-frequency signals.

[0050] As shown in Figure 2, the high and low frequency detection includes the following steps:

[0051] S110. Set the high-frequency signal threshold and calculate the signal change amplitude between each current sample signal and the previous sample signal in the video signal.

[0052] Specifically, in this embodiment, the signal change amplitude is a positive value, and its calculation formula is as follows: This facilitates the determination of high-frequency signals in each sample point of the video signal by comparing the amplitude of the signal change with a set high-frequency signal threshold. It should be noted that the high-frequency signal threshold set in this embodiment can be flexibly set according to the characteristics of the actual video signal. The setting principle is: in the video signal, the amplitude of the high-frequency signal interval sample change is one-tenth of the overall amplitude; the calculation formula is: th = (S max -S min ) / 10, where th represents the high-frequency signal threshold; S max S represents the maximum signal strength of the video signal. min This represents the minimum signal value of the video signal.

[0053] S120. Based on the signal change amplitude and the high-frequency signal threshold, determine the signal type of each current sample signal, and count the high-frequency signals based on the signal type of each current sample signal.

[0054] Specifically, determining the signal type of each current sample signal and performing high-frequency signal counting based on the signal type of each current sample signal includes the following steps: determining whether the amplitude of each signal change is greater than or equal to the high-frequency signal threshold; if yes, then determining that the signal type of the current sample signal corresponding to the amplitude of the signal change is a high-frequency signal; if no, then determining that the signal type of the current sample signal corresponding to the amplitude of the signal change is a low-frequency signal.

[0055] When the signal type is a high-frequency signal, determine whether the high-frequency signal count value is equal to the maximum count threshold. If yes, the high-frequency signal is not counted; otherwise, the high-frequency signal count is incremented by "1". When the signal type is a low-frequency signal, determine whether the high-frequency signal count value is equal to the minimum count threshold. If yes, the high-frequency signal is not counted; otherwise, the high-frequency signal count is decremented by "1". The initial count value is the minimum count threshold, and the initial count value is the same as the number of samples in the sample interval.

[0056] Since the signal type determination of a single sample point in a video signal cannot show the continuity of signal changes in the video signal, it is unstable. If the signal type determination result of a single sample point signal is used as the basis for the final filtering process, it will increase the load on the filtering process. Therefore, after determining the signal type of each sample point signal in the video signal, it is necessary to further use the counting function of a counter to count the high-frequency or low-frequency signals in the determination result, so as to facilitate the determination of signal continuity. The counting range of the counter is [minimum counting threshold, maximum counting threshold].

[0057] It should be noted that the initial value of the counter is set to the minimum interval length of the high-frequency signal in the video signal, and is expressed as a negative value. Before detecting high and low frequency signals, the staff can obtain the minimum interval length of the high-frequency signal of the video signal to be detected in advance, and then count the signal. On the other hand, the negative value of the minimum interval length is also set as the minimum counting threshold in this embodiment, so as to ensure that the high-frequency signal with the minimum interval length can be judged and avoid misjudgment or omission of high-frequency signal detection.

[0058] Specifically, this embodiment takes the minimum interval length of high-frequency signals in the video signal as 16 as an example. In this case, the initial value of the counter is set to -16, and the minimum counting threshold is also set to -16.

[0059] At this point, if the current sample signal is determined to be a low-frequency signal, the counter is further checked to see if the high-frequency signal count value is -16. If it is, the counter does not count and maintains the current high-frequency signal count value to ensure that the high-frequency signal with the smallest interval length can be identified. If the high-frequency signal count value is not -16, the counter decrements the high-frequency signal count value by "1" to count the continuous low-frequency signal.

[0060] If the current sample signal is determined to be a high-frequency signal, then it is further determined whether the high-frequency signal count value in the counter is the maximum counting threshold. If it is, the counter does not count and maintains the current high-frequency signal count value. If the high-frequency signal count value is not the maximum counting threshold, the counter increments the high-frequency signal count value by "1".

[0061] S130. Based on the counting results of high-frequency signal counting, the signal type of the sample interval is obtained, wherein the sample interval is a signal interval formed by multiple consecutive sample signals, and the length of the sample interval is the minimum interval length where high-frequency signals exist in the video signal.

[0062] The method for determining the signal type of a sample interval based on the counting results of high-frequency signals includes the following steps: comparing the counting results corresponding to each sample interval of the video signal with zero crossings; if the high-frequency signal count value in the counting result is greater than zero, the signal type of the sample interval is determined to be a high-frequency signal, otherwise it is a low-frequency signal.

[0063] The signal judgment of the sample interval is used to solve the problem of instability in the detection results of a single sample signal. By using the sample interval, the judgment of continuous high-frequency or low-frequency signals can be achieved, thereby increasing the signal feature significance of high-frequency signals and low-frequency signals in the video signal, while reducing the load on subsequent filtering processing.

[0064] Specifically, when the high-frequency signal count value of the counter is greater than zero, the length of the previous segment of the current signal is considered to be... The sampling interval is a high-frequency signal.

[0065] After high and low frequency signal detection is completed, filtering can be performed. The principle of filtering is that when HF... - When en=1, signal filtering is performed, and the filtered signal is output. When HF - When en=0, no signal filtering is performed, and a direct signal is output. The specific steps are as follows:

[0066] S200. Based on high and low frequency detection, the video signal is subjected to the first synchronization delay processing to obtain the first synchronization delay signal. In the first synchronization delay processing, the video signal is delayed according to the delay generated by the register of high and low frequency detection and the delay generated by the logic detection cycle of high and low frequency detection.

[0067] Because the registers in the circuit used for high and low frequency detection of video signals will generate a delay in units of clock cycles, and the high and low frequency detection will also generate an algorithmic delay, it is necessary to further delay the video signal. The synchronous delay signal 1 after delay processing is used as the filtering object for selective filtering, so that the synchronous delay signal 1 is aligned with the high-frequency and low-frequency signals of the video signal after high and low frequency detection. This ensures that during the filtering process, selective filtering can be performed accurately based on the high-frequency and low-frequency signals identified in the video signal, thus ensuring the accuracy of the filtering results.

[0068] S300. Based on the detection results, perform selective filtering on the first synchronization delay signal to obtain a filtered signal. At the same time, based on the filter register delay, perform a second synchronization delay on the first synchronization delay signal to obtain the second synchronization delay signal.

[0069] The selective filtering process includes the following steps: filtering the signal region in the first synchronous delay signal that corresponds to the sample interval marked as a high-frequency signal; and not filtering the signal region in the first synchronous delay signal that corresponds to the sample interval marked as a low-frequency signal.

[0070] Specifically, the sample intervals marked as high-frequency signals in the video signal are filtered along with the corresponding signal regions in the synchronization delay signal, and the filtered signals of the intervals are output. The sample intervals marked as low-frequency signals in the video signal are not filtered along with the corresponding signal regions in the synchronization delay signal, and the output signals are passed through. The filtered signals and passed through signals of each interval are combined according to the timestamp of the video signal to obtain the complete filtered signal.

[0071] On the other hand, since the registers in the circuit used for selective filtering will generate a delay during selective filtering, it is necessary to further delay the first synchronous delay signal to obtain the second synchronous delay signal, so that the second synchronous delay signal is aligned with the complete filtered signal, thereby facilitating the obtaining of an accurate filtered output signal in the final output.

[0072] S400. Based on the detection results, selectively output the filtered signal and the second synchronous delay signal to obtain the filtered output signal. During the second synchronous delay processing, the first synchronous delay signal is delayed according to the delay generated by the register in the filter.

[0073] The selective output filtering signal includes the following steps: when the sampling interval is a high-frequency signal, the region of the filtered signal corresponding to the sampling interval is selected as the output; when the sampling interval is a low-frequency signal, the region of the synchronous delay signal II corresponding to the sampling interval is selected as the output.

[0074] Because the output of the low-frequency signal sample interval is a direct signal during selective filtering, and in order to ensure that the low-frequency signal in the final filtered output signal maintains high fidelity with the original video signal, the low-frequency signal in the filtered output signal is kept consistent with the low-frequency signal in the video signal by selectively outputting the filtered signal and the synchronization delay signal.

[0075] Figure 3 shows the simulated waveforms of the signals obtained by the above filtering method for a selected video signal at each stage. As can be seen from the figure, HF_en (the waveform of the signal after high and low frequency detection) has a certain delay compared to the video signal. Therefore, the video signal is subjected to the first synchronization delay processing to obtain the output signal after the first stage of delay synchronization: synchronization delay signal one. Through the first synchronization delay processing, HF_en is aligned with synchronization delay signal one, and the HF_en=1 part can completely cover the high-frequency part of synchronization delay signal one.

[0076] Using HF_en as the enable signal, the synchronous delay signal 1 is selectively filtered to obtain the filtered signal. When HF_en=1, the filtering circuit outputs the filtered data of the synchronous delay signal 1. When HF_en=0, the filtering operation stops, and the output remains the last output before HF_en was pulled low.

[0077] The second synchronous delay signal is the second-stage delay output. Through the second synchronous delay processing, the second synchronous delay signal can be aligned with the filter signal. Finally, HF_en is used to select between the second synchronous delay signal and the filter signal to obtain a filter output signal containing only low-frequency signals.

[0078] Example 2

[0079] As shown in Figure 4, a video signal filtering circuit includes a high / low frequency detection circuit, a delay synchronization circuit one, a filtering circuit, a delay synchronization circuit two, a first selector, and a second selector. The output of the high / low frequency detection circuit is connected to the input of the first selector and the second selector, respectively. The output of the delay synchronization circuit one is connected to the input of the filtering circuit and the input of the delay synchronization circuit two, respectively. The output of the filtering circuit and the output of the delay synchronization circuit two are both connected to the input of the second selector. The output of the first selector is connected to the input of the filtering circuit.

[0080] The high and low frequency detection circuit receives the input clock and video signal, performs high and low frequency detection on the video signal, and outputs the detection result. The first selector outputs a digital signal based on the output detection result. The first delay synchronization circuit performs a first synchronization delay processing on the video signal based on the high and low frequency detection to obtain a synchronization delay signal one. The filtering circuit performs selective filtering processing on the synchronization delay signal one based on the detection result to obtain a filtered signal. The second delay synchronization circuit performs a second synchronization delay processing on the synchronization delay signal one based on the filter register delay to obtain a synchronization delay signal two. The second selector selectively outputs the filtered signal and the synchronization delay signal two based on the detection result to obtain a filtered output signal.

[0081] Specifically, taking the video signal filtering circuit structure shown in Figure 4 as an example, the input clock signal is clk, and the video signal is video. - signal, filtered signal flt - signal.

[0082] First, the video signal passes through a high-low frequency detection circuit to obtain HF_en. When the detected signal is a high-frequency signal, HF_en=1; otherwise, HF_en=0.

[0083] The input video signal is then processed by the delay synchronization circuit to perform the first synchronization delay, so that the high frequency range of the processed signal corresponds to HF_en, and the synchronization delay signal syn1_signal is obtained.

[0084] The clock switch of the filter circuit is controlled by HF_en. When HF_en=0, the clock of the filter circuit is pulled low and the filter circuit is in a non-working state; when HF_en=1, the clock of the filter circuit is equal to the input clock clk and the filter circuit is in a working state.

[0085] The first synchronous delay signal syn1_signal, after the first synchronous delay processing, undergoes further synchronous delay processing through the second delay synchronization circuit to ensure that the phase of the signal after the two synchronizations remains aligned with the output signal of the filter circuit, thus obtaining the second synchronous delay signal syn2_signal.

[0086] Finally, with HF_en enabled, the filtered signal flt is processed through the second selector. - The signal and the synchronization delay signal syn2_signal are selected. When HF_en=1, it indicates that the current video signal is in the high frequency range and needs to be filtered, and the filtered signal is output. When HF_en=0, it indicates that the current video signal is in the low frequency range and does not need to be filtered, and the filtered output signal is output.

[0087] Since the video signal filtering circuit in this embodiment performs the video signal filtering method shown in Embodiment 1, it will not be described in detail in this embodiment.

[0088] Example 3

[0089] A computer-readable storage medium storing a computer program, which, when executed by a processor, implements a video signal filtering method according to Embodiment 1.

[0090] More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wire segments, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0091] In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless segments, wire segments, optical cables, RF, etc., or any suitable combination thereof.

[0092] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of modules, units, or units is merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units, modules, or components may be combined or integrated into another device, or some features may be ignored or not executed.

[0093] The units may or may not be physically separate. The components shown as units can be one or more physical units, meaning they can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0094] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0095] In particular, according to embodiments disclosed in this invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this disclosure include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication component, and / or installed from a removable medium. When the computer program is executed by a central processing unit (CPU), it performs the functions defined in the methods of this application. It should be noted that the computer-readable medium described above in this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof.

[0096] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0097] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for filtering video signals, characterized in that, Includes the following steps: Receive a video signal, perform high and low frequency detection on the video signal, and output the detection result, wherein outputting the detection result includes marking each sample point interval of the video signal as a high frequency signal or a low frequency signal; Based on the high and low frequency detection, the video signal is subjected to the first synchronization delay processing to obtain synchronization delay signal one; Based on the detection results, the first synchronization delay signal is selectively filtered to obtain a filtered signal. Simultaneously, based on the filter register delay, the first synchronization delay signal is subjected to a second synchronization delay to obtain a second synchronization delay signal. The selective filtering process includes the following steps: filtering the signal region in the first synchronization delay signal corresponding to the sample intervals marked as high-frequency signals; and not filtering the signal region in the first synchronization delay signal corresponding to the sample intervals marked as low-frequency signals. Based on the detection results, the filtered signal and the second synchronization delay signal are selectively output to obtain the filtered output signal.

2. The video signal filtering method according to claim 1, characterized in that, The high and low frequency detection includes the following steps: Set a high-frequency signal threshold and calculate the amplitude of the signal change between each current sample signal and the previous sample signal in the video signal; Based on the signal change amplitude and the high-frequency signal threshold, the signal type of each current sample signal is determined, and high-frequency signal counting is performed based on the signal type of each current sample signal. Based on the counting results of high-frequency signals, the signal type of the sample interval is obtained, wherein the sample interval is a signal interval formed by multiple consecutive sample signals, and the length of the sample interval is the minimum interval length where high-frequency signals exist in the video signal.

3. The video signal filtering method according to claim 2, characterized in that, Determine the signal type of each current sample signal and perform high-frequency signal counting based on the signal type of each current sample signal, including the following steps: Determine whether the amplitude of each signal change is greater than or equal to the high-frequency signal threshold; If yes, then the signal type of the current sample signal corresponding to the change in amplitude of the signal is determined to be a high-frequency signal; otherwise, the signal type of the current sample signal corresponding to the change in amplitude of the signal is determined to be a low-frequency signal. When the signal type is a high-frequency signal, determine whether the high-frequency signal count value is equal to the maximum count threshold. If yes, the high-frequency signal is not counted; if no, the high-frequency signal count is incremented by "1". When the signal type is a low-frequency signal, determine whether the high-frequency signal count value is equal to the minimum count threshold. If yes, the high-frequency signal is not counted; if no, the high-frequency signal count is decremented by "1". The initial count value is the minimum count threshold and is the same as the number of samples in the sample interval.

4. The video signal filtering method according to claim 2, characterized in that, Based on the counting results of high-frequency signals, the signal type of the sample interval is obtained, including the following steps: The counting results corresponding to each sample interval of the video signal are compared with zero-crossing. If the high-frequency signal count value in the counting result is greater than zero, the signal type of the sample interval is determined to be a high-frequency signal; otherwise, it is a low-frequency signal.

5. The video signal filtering method according to claim 1, characterized in that, During the first synchronization delay processing, the video signal is delayed based on the delay generated by the high and low frequency detection registers and the delay generated by the logic detection cycle of high and low frequency detection.

6. The video signal filtering method according to claim 1, characterized in that, During the second synchronization delay processing, the synchronization delay signal one is delayed based on the delay generated by the register in the filter.

7. The video signal filtering method according to claim 1, characterized in that, Selectively filtering the output signal includes the following steps: When the sampling interval is a high-frequency signal, the region of the filtered signal corresponding to the sampling interval is selected as the output. When the sampling interval is a low-frequency signal, the region of the synchronous delay signal two corresponding to the sampling interval is selected as the output.

8. A video signal filtering circuit, characterized in that, The video signal filtering circuit performs the video signal filtering method according to any one of claims 1-7, including a high-low frequency detection circuit, a delay synchronization circuit one, a filtering circuit, a delay synchronization circuit two, a first selector, and a second selector. The output terminal of the high-low frequency detection circuit is connected to the input terminals of the first selector and the second selector, respectively. The output terminal of the delay synchronization circuit one is connected to the input terminal of the filtering circuit and the input terminal of the delay synchronization circuit two, respectively. The output terminals of the filtering circuit and the delay synchronization circuit two are both connected to the input terminal of the second selector. The output terminal of the first selector is connected to the input terminal of the filtering circuit. The high and low frequency detection circuit is used to receive the input clock and video signal, perform high and low frequency detection on the video signal, and output the detection result; The first selector is used to output a digital signal based on the output detection result; The delay synchronization circuit one is used to perform the first synchronization delay processing on the video signal based on high and low frequency detection to obtain the first synchronization delay signal; The filtering circuit is used to selectively filter the synchronization delay signal one according to the detection result to obtain a filtered signal. The selective filtering process includes the following steps: filtering the signal region in the synchronization delay signal one that corresponds to the sample interval marked as a high-frequency signal; and not filtering the signal region in the synchronization delay signal one that corresponds to the sample interval marked as a low-frequency signal. The second delay synchronization circuit is used to perform a second synchronization delay processing on the first synchronization delay signal according to the filter register delay, so as to obtain the second synchronization delay signal. The second selector is used to selectively output the filtered signal and the synchronization delay signal based on the detection result, so as to obtain a filtered output signal.

9. A non-transitory computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it performs the video signal filtering method as described in any one of claims 1-7.

Images