TW201041373A - Vertical synchronization processing method and circuit for composite video signal - Google Patents

Abstract

A vertical synchronization processing method for a composite video signal is provided. The method includes the following steps: determining whether a predetermined number of scan lines in the composite video signal corresponds to a feature of a specific field in turn; assigning numbers to each of the scan lines in the composite video signal to generate a scan-line-index signal when the predetermined number of the scan lines corresponds to the feature of the specific field; determining a field type based on the scan-line-index signal and the feature of the specific field and outputting a vertical synchronization confirm signal.

Description

201041373 VI. Description of the Invention: [Technical Field] The present invention relates to the processing of composite video signals, in particular to a vertical synchronization processing method for composite video signals and related circuits . 〇 [Prior Art] Composite video (CVBS), or composite video, refers to a video signal with a sync signal. For analog video signals of analog TVs, these signals not only have the data of each scan line, but also the information of synchronization between the frame and the face. After the receiver receives the composite video signal, it needs These sync signals can be accurately detected, and the boundaries of each picture and each scan line can be correctly distinguished accordingly. Since the composite video signal uses an interlaced scan to interleave the data of the 〇dd field and the even field (even line), it is necessary to have appropriate at the receiving end. The circuit determines the type of the field to be received to confirm that it is an even field or an odd field, and accordingly marks each scan line with the correct scan line number for subsequent The decoding process. However, the vertical sync detection mechanism applied by today's composite video signals often causes errors when the signal quality is poor or serious noise is generated, and the 201041373 surface during playback is shaken, scrolled, or even unable to complete synchronization. The situation has occurred, which has seriously affected the quality of the viewing. Therefore, there is a need to provide a novel vertical synchronization processing circuit and related methods to solve the problems of the prior art, and even in the case of high noise, the vertical synchronization of the signal can be correctly performed to ensure the playback quality. . SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a vertical synchronization processing method suitable for a composite video signal and related circuitry that can be stably operated in various states to maintain the quality of the output video. According to an embodiment of the present invention, a vertical synchronization processing method is disclosed. The method includes: sequentially determining, in the composite video signal, whether a predetermined number of scan lines have a specific field feature; and when the predetermined number of scan lines have the specific field feature, each scan line of the composite video signal Encoding is performed to generate a broom line track number; and according to the _ line coded signal and the ultra-fine field feature, the vertical field confirmation signal is outputted by the lying field type '.

According to another embodiment of the present invention, a vertical synchronization detection circuit is disclosed, and the vertical synchronization detection circuit is coupled to a horizontal synchronization detection circuit for receiving a sampling point signal and a horizontal synchronization. Confirm the signal. The circuit has a feature detection circuit, a sweeping cat line numbering circuit, and a vertical synchronization judging circuit. The feature detection circuit 5 201041373 sequentially determines whether a predetermined number of scan lines in the composite video signal have a specific field feature based on the sampling point signal and the horizontal synchronization confirmation signal. The scan line code circuit encodes each scan line of the composite video signal according to the sampling point signal, the horizontal synchronization confirmation signal, and the determination result of the characteristic detection circuit to generate a scan line coded signal. The vertical synchronization judging circuit judges the correct field type according to the scan line coded signal and the judgment result of the feature detection circuit, and rotates a vertical sync confirmation signal, wherein the vertical sync judging circuit encodes according to the scan line The Q signal and the judgment result of the feature detecting circuit calculate the total number of scan lines corresponding to one of the specific field features to determine the field type and output a vertical sync confirmation signal. By the embodiments of the present invention, which include circuit diagrams of some of the circuits and their internal circuit components disclosed in the Summary of the Invention, the problems encountered in the prior art can be solved or avoided and technical or . The technical features and advantages of the present invention will be briefly described in order to make the subsequent inventions easier to understand, and additional technical features and related details of the present invention will be disclosed later, and are claimed in the scope of the present application. The scope of the claim. Those skilled in the art should be able to modify or design other structures or processes that achieve the same objectives of the present invention as well as those skilled in the art. The scope of the present invention is not limited by the scope of the present invention and the scope of the claims. 6 201041373 [Embodiment] 词汇 In the scope of this patent specification and the subsequent patent application, the vocabulary is referred to as "special". There are some common solutions in the field, and hardware manufacturers may use different nouns to refer to the same one. The applicant should be able to bury the specification and the subsequent patent application scope is not a difference in name. The way of the component is to make the difference in the function of the component: The terminology of the reference in the entire specification and subsequent claims is an open term and should be interpreted as "including but not limited to two:" "coupled" - the word is included here. Any direct and indirect electrical connection 2 . 'Therefore, as described in the text - the device is connected to the second device, it means that the first device can be directly electrically connected to the $2 device, or indirectly connected to the second device through other devices or connection means. . Please refer to FIG. 1A', which is a schematic diagram of an embodiment of a video processing circuit of the present invention. As shown in FIG. 1, the video processing circuit 100 includes, but is not limited to, a horizontal synchronization detecting circuit 110, a vertical synchronization processing circuit 120, and a signal processing unit 13A. As shown, the horizontal synchronization detection circuit 110 receives a composite video signal sCVB to perform a horizontal synchronization (Horizontal Synchronization) related operation. After the horizontal synchronization is completed, the horizontal synchronization debt measuring circuit 110 provides a sampling point number Ssample-index to the vertical synchronization processing circuit ι2 〇 and the signal processing unit 130' to confirm that each sampling point is in one scanning line. 7 201041373 The location of the representative. For example, in the composite video signal system of the National Television standards Committee (NTSC) standard, with a sampling frequency of 24.576 MHz, each scanning line has 1562 sampling points at a frequency of 15.734 KHZ. In addition, when the horizontal synchronization operation is completed, the horizontal synchronization detecting circuit 11 also issues a horizontal synchronization confirmation signal HSYNC-lock to the vertical synchronization processing circuit 120 and the signal processing unit 130' to inform that the horizontal synchronization has been completed. The vertical synchronization processing circuit 12 is consuming the horizontal synchronization detection circuit 11 〇 for performing further vertical synchronization operation on the composite video signal sCVB after the horizontal synchronization operation is completed. During the vertical synchronization operation, the vertical synchronization processing circuit 12 controls the feature detection circuit 14A, the vertical synchronization determination circuit 15A, and the scan line number circuit 16A for vertical synchronization. m synchronously confirms the money vs YNc_iGek to the signal unit 130' and provides a corresponding number for each scan line

Line index, 卩 informs the time after the signal processing single & $ one scan line in the entire screen (fmme), for subsequent signal processing #. However, the above-mentioned circuit configuration and circuit elements have only been used as examples and are not limiting of the invention. For example, the horizontal synchronization processing circuit, the vertical synchronization processing circuit, and the occupation processing unit 130 are integrated into the same-electrical-block, and in other embodiments of the present invention, the scanning line numbering circuit can be independent. In addition to the horizontal block detection circuit 8 201041373 circuit 110 and the vertical synchronization processing circuit 120 circuit block; in addition, depending on the circuit 1G0 can also be added according to the needs of the s ten need to add other circuits • 7G pieces k# * The related design changes are transferred to the scope of the present invention within the spirit of the invention. In the vertical synchronization processing circuit 12G, the feature detection circuit can sequentially determine, according to the sampling point number Ssample_index and the horizontal synchronization confirmation signal 〇HSYNCM0ck, that a predetermined number of scanning shirts in the received composite video signal have a special (four) texture. (Charming frequency sign), and output the feature signal. The feature detection circuit can just use different identification mechanisms according to different design requirements to determine that the predetermined number of scan lines in the received composite video signal s(10) are material-specific. The scan line numbering circuit 160 converts and subtracts the line code according to the feature signal, the sample point number Ssampie index, and the horizontal sync confirmation signal HSYNCAek, and outputs (4) the line number. Vertical synchronization judgment circuit! 5〇 According to the feature signal and the scan line ^ 〇 number Line-index for vertical synchronization and field type determination, the round-up vertical sync confirmation signal VSYNC-lock to the signal processing unit 130, informing that the vertical synchronization has been completed and according to the figure The result of the field type determination produces a control signal cs to the scan line numbering circuit 160. The scanning line number circuit 16A corrects the sampling point number Ssample-index based on the control sfl number CS. Please refer to Figure 1 to see Figure 2 and Figure 3. Figure 2 shows a composite video signal that complies with the National Televisi〇n '201041373 standards committee (NTSC) standard. Figure 3 shows a composite video signal that complies with the I-phase phase aiternati〇n Hne (pal) standard. In a first embodiment of the present invention, the feature detecting circuit 14G can adopt a horizontal synchronization signal width pattern algorithm 'by observing the horizontal synchronization signal width of the scanning line (the low level in the initial part of the scanning line) The feature of the bit is to detect whether the predetermined number of scan lines in the composite video signal Sew have a specific field feature; in addition, in a second embodiment of the present invention, the feature detecting circuit 14 〇 A line-of-line transition algorithm can also be used to detect whether a predetermined number of scan lines in the composite video signal have a specific field characteristic by observing the characteristics of the low-level width in the middle portion of the scan line. . When a specific field feature is detected, the vertical synchronization determining circuit 15 can calculate the total number of scan lines corresponding to the specific field feature by the scan line number Line_index and compare it with a predetermined number of scan lines to determine the field. The class is an odd field or an even field, and outputs a vertical sync signal VSYNCMock to the signal processing unit 130, and a control signal cs to the scan line number circuit. Further, the vertical synchronization judging circuit 15 can further observe whether or not the appearance rule of the field type is a predetermined appearance rule to turn out the 'vertical synchronization confirmation signal VSYNC-lock. The horizontal synchronizing signal width and the in-line feature judging method of the present invention will be described in detail as follows. Please continue to see Figure 2. For a composite video signal conforming to the National Television System Committee (NTSC) standard, each picture of the composite video signal consists of an odd field (consisting of scan line 1 to scan line 262) and an even picture 201041373 field = scan line 263 ~ scan line 525 constitutes the composition, please note that because # first transmission of the H i staff meeting (job) standard, the position of the composite video signal line, ha 'transmission instead of the screen scan, 4 Φ odd field actual The system includes - the number of strokes in the written number of strokes (that is, the flute in the face) (5) the odd-numbered sweep of the s song), and the even map field, the sweep of the entire scan line, etc., "This Ο ❹ (ie, the second body in the face: including the even-numbered scan line push in one screen), therefore, the second figure, the -f, the fourth scan line, etc., with such odd-numbered scan lines, The scanning line τ of the τ and the scanning line 262 is the scanning line 263 of the even-numbered picture in the picture, and the scanning line of the National Television System Committee of the scanning line. As shown in the figure, for a composite video signal that has 525 lines per screen in the United States and its C standard, line 9 is a special feature scan line: in the odd field, the scan line! To the sweeping signal; for the even and the some scan lines do not have the characteristic μ* feature sweep: coffee 'sweep line-scan':::: clear reference 3 fSI · F1 4 installed 1J · composite video signal = = European regulations - ^ 忠 The loyalty corresponds to the 625 broadcasts including the sweep line 1 to the scan line 312, and the even map field of the C specification includes ^ progressive, in addition to the broadcast shown in Figure 3.蠄谉 线 line 625, the middle scan r. refers to the position of the transmission and the position of the northern all-known line, that is, the 3rd π instead of the 扫描面不不 scan line 1 to the sweep line 312 201041373 The odd-numbered scan lines, and the scan lines 313 to 625 shown in FIG. 3 are even-numbered scan lines in the face. For the US National Television System Committee (NTSC) composite video signal, the European standard progressive backward (PAL) composite video signal, or other composite video signals of the other specifications, due to the odd map field and the even picture The front end of the field has a special scan line group (such as scan line 1 to scan line 9 in the composite video signal conforming to the National Television System Committee (NTSC) standard, and a combination of the National Television System Committee (NTSC) standards. A scan line 263 to a scan line 272) in the video signal, wherein a predetermined number of scan lines in a particular scan line group have a specific field feature, that is, one of the objects of the present invention is to provide a horizontal sync k A pattern algorithm and a transition algorithm are used to determine the type of the field by observing whether a feature of a predetermined number of scan lines in the composite video signal conforms to a particular field feature. To confirm that each field is an odd field or an even field, and output a vertical synchronization confirmation signal VSYNC-lock. The horizontal sync signal width feature judging method is to detect whether a predetermined number of scan lines in the composite video signal SCVB have a horizontal sync 彳5 break width (a portion of the low level in the start portion of the scan line) of the scan line. A specific field feature. Taking a composite video signal conforming to the National Television System Committee (NTSC) standard as an example, it can be found from the scan line sequence of the composite video signal that the width of the horizontal sync signal in the beginning of each scan line is not all the same (eg 2, wherein the scan line 524 and the scan line 525 are normal 12 201041373 with data, and for the scan line 1 to the scan line 3, the width of the horizontal sync signal is about the positive scan line level. The width of the sync signal is half; as before, the sweep "line 4 knows that the line 6 also belongs to a special feature scan line, and the horizontal sync (four) width of the scan line 4 to the scan line 6 is wider than the normal scan line. The width is wide, however, after the scan line Η), the odd map field knows that the line's horizontal sync signal width has returned to the normal width.简 In short, for the National Television System Committee (NTSC) standard ^ composite video (4), if the positive (four) scan _ horizontal sync signal is wide (_ Ϊ ' _ scan line horizontal sync signal width is marked as s (s_ ), and the longer horizontal sync signal width of the sweep line is labeled as 〇〇ng), then the width of the horizontal sync signal width of each scan line can be determined first to detect whether the predetermined number of scan lines have a specific Field feature (vertical synchronization feature). For example, when the composite video is shouted to meet the standards of the NTSC, if the feature circuit 14 判 reads a set of horizontal sync signals in a predetermined number of scan lines, the width is nnsssl-l_l-s-s_s -n, which means that the feature intrusion circuit i measures the specific field characteristics of the field (as shown in Figure 2) and issues the feature $0 Odd-field-match and Even-field-match. In the embodiment of ;^ 私日日七θ十知乃', since the specific field features of the singular field and the even field are all NNSSSLLLSS-S_N, when finding the specific field features, 垂13 201041373 is the same The Y judging circuit 150 can calculate the total number of scan lines of the characteristics of the special money field and the number of predetermined scan lines (10) to make a "line or 263 scan lines" by the scan line number Line_index, and confirm the figure to confirm the figure. The field type is odd field (262 sweep lines) or even field (263 scan lines). Similarly _ in accordance with the European standard progressive backward (PAL) standard composite video. The horizontal sync signal width of the scan line can be observed to detect whether the predetermined number of scan lines have a specific field feature in the composite video signal SCVB. The horizontal sync signal width feature judging method, the vertical sync processing circuit and the judging The processing circuit of the composite video signal conforming to the line-by-line backward ceramic standard is processed, and the processing circuit of each field field type is processed. In the present invention, the real circuit (10) is interpreted in the number of scan lines. Sync ^ The secret is called Can Che, the job shows this = special ^_ direct synchronization feature) and can send the characteristic signal ◦ dd-tield-match; back to the description, the raft 4_, sweep the y-line, the temple sign detection circuit 140 A predetermined number (four) of lines is interpreted as a set of horizontal sync signal widths of 'that indicates that the even field of the even field is detected at this time, and the characteristic signal trfieitmateh can be emitted. When _ is to a specific field feature According to the leaf user's demand, whether it should be counted in the lychee field, the number of lines (five) scan lines (four) 313 sweeps and sweeps to confirm the map field odd _312___ two = 201041373 scan lines). For the composite and signal of the progressive backward (Pal) standard, the specific field features of the odd and even fields are not the same. The video can be selected according to the designer's selectivity. The total number of lines and a predetermined number of scanning lines are used to confirm the field type again. Referring to FIG. 4, FIG. 4 is a flow chart showing the operation of the vertical synchronization processing circuit 120 of the present invention using the horizontal synchronization signal width feature determination method. The process includes the following steps: w Step 410: Flow of the process Step 420: sequentially determine whether a predetermined number of sweep lines in the composite video signal have a specific field feature. The horizontal synchronization signal width feature determination method is used to determine whether a specific circular field feature is read. If the scan line has a specific field feature, step 430 is performed; otherwise, returning to step 42. In an embodiment of the present invention, the feature preparation circuit 140 determines whether the image is read at this time. The specific field feature of the field, if yes, step 430. _ 430: When a predetermined number of scan lines have a specific field feature, each scan line of the composite video signal is encoded to generate a scan I, which is a code money. According to the sweeping code signal and the specific market characteristics, to determine the correct field _ is the _ field or the odd field. + For example, 'When the feature % of the even field is detected in step 42G, 'starting the editing of each scan line 201041373, and according to the coding of each scan line, the corresponding map feature is obtained. If the total number of scan lines is the same as the total number of broom lines corresponding to the even field, step 440 is performed; otherwise, return to step 420. / Step 440. Check the next field signal. If all the fields in the field meet the corresponding field order, proceed to step 4 5 〇, otherwise, return to step 430. For example, if it is determined in step 430 that the field received at this time is an even field (the total number of sweep lines corresponds to the total number of scan lines of the even field), then successive fields are determined. Whether the total number of scan lines owned corresponds to the order of the field (such as odd field _> even field -> odd field -> even field), if the total number of consecutive fields is higher than one When a threshold value Thdl is reached, step 450 is performed. Step 450: Output a vertical synchronization confirmation signal vSY]Sfc_iock and end the flow. Next, the in-line feature judging method of the present invention will be explained. Please continue to refer to Figures 2 and 3. For the composite video signal SCVB, the width of the interval (the width of the low level portion) in each of the scanning lines also changes. The in-line feature judging method of the present invention detects whether a predetermined number of scan lines have a specific field feature (vertical sync feature) by judging the interval width of the middle portion of the scan line. Taking the video signal of the National Television System Committee (NTSC) standard 16 201041373 as an example, observing the composite video signal (as shown in Figure 2), it appears that in the middle of scan line 3 (scan line 265) A shorter width section of the lower level can be marked as S. In the middle portion of the known line 4 (scanning line 266), a low-level low-level section appears, which can be labeled $L. &Henju said that the feature detecting circuit 140, when a predetermined number of scanning lines are ordered to read a group of scanning lines, is characterized by SL (the low-level width variation of the middle portion of two consecutive scanning lines), that is, the detection A specific field feature is detected and signals 〇 Even-field-match and 0dd-field_match are sent to the scan line numbering circuit 160. In another embodiment, the feature detecting circuit 14() can further observe the width (horizontal sync signal width) of the starting portion in the scan line 3 (scan line 265) and the scan line 4 (scan line 2 66). The width of the middle part is used to distinguish the type of the field from the odd field or the even field. That is to say, when the composite video signal sCVB conforms to the specifications of the National Television System Committee (NTsc), the feature detection circuit just in the predetermined number of scan lines _ - the middle part of the smear line = levy ^ after 'and corresponding The beginning of the scan line (horizontal sync signal = f is also S_L' means that the feature of this segment corresponds to the scan of the odd field. The number of features is required to be at the beginning of the corresponding scan line. Between the feature and the scan line; / between the line 3 and the scan line starting point of the scan line 4. The file feature 'and the scan line 265 to the scan line 266 sweep 201041373 line start feature and the scan line middle part feature), Then, it can be judged that the pattern field at this time is used to emit a corresponding signal.

Even-field-match or

Odd-field-match to scan line numbering circuit 16〇. On the other hand, when the composite video signal SCVB complies with the European standard progressive backward (PAL) standard, the feature detecting circuit 14 detects a middle portion of the scanning line in a predetermined number of scanning lines as S_L (scanning line 625~). The scan line 丄 and the scan line 312 312 313 are detected to detect a specific field feature, and the signals Even-field-match and 〇 dd-field-match are sent to the scan line number circuit 160. In another embodiment, when the feature detection circuit 14 detects a specific field feature, it can further observe the corresponding scan line horizontal synchronization number width to determine the type of the field at this time. Signal the Even-field-match or 〇dd-field-match. Referring to Fig. 5, Fig. 5 is a flow chart showing the operation of the vertical synchronization processing circuit ❹ 120 of the present invention using the in-line feature judging method. The process includes the following steps: Step 510: The process begins. Step 520: sequentially determining whether a predetermined number of scan lines in the composite video signal have a specific field feature. Use the in-line feature judgment method to determine whether a specific field feature is read? If there is a pre-number, the finger line has a particular field feature, then -5 530; otherwise, 'back to step 520. For example, in one embodiment of the present invention, the feature-preferred circuit 140 determines whether a particular field of the even field is read at this time. If yes, step 530 is performed. The field pattern feature is as follows: Step 530: When a predetermined number of sweeps have a characteristic field feature, each scan line of the video signal is made, and the paper horse produces a broadcast/.Α coded signal. According to the scan line, the grasshopper lacks R δ 9 Hita Green ° ’U and the specific map field to determine the correct type of the field is the pigeon figure. Wind, Ο 勿 Do not 5 乂 March. For example, when the feature field feature of the even field is _ in step 520, the coding of each scan line is started, and the scan line corresponding to the feature of the field is obtained according to the stone of each broom line. When the total number is the same as the total number of scan lines corresponding to the even field, step 540 is performed; otherwise, I goes to step 520. ^ Step _: Observe the next field signal. If the corresponding field is connected to the field, go to step 550. Otherwise, go back to step 530. For example, when it is determined in step 53 that the field received at this time is an even field (the total number of the women's and women's lines corresponds to the total number of scan lines of the even field; and;; the direct synchronization determining circuit 150 will judge Whether the total number of scan lines owned by successive fields is corresponding to the order of the field (such as odd field _> even field · gt; odd figure private field), if the total number of consecutive fields is consistent When it is higher than a first threshold Thdi, step 55 is performed. 19 201041373 Step 55: A vertical synchronization confirmation signal VSYNC_lock is output, and the flow is ended. However, the vertical synchronization processing circuit 12 uses a horizontal synchronization signal. The width feature judging method or the in-line feature judging method is used to determine the type of the field, and the feature detecting circuit 14G must calculate the low-level width corresponding to each scan line in a predetermined number of scanning lines (the initial portion and / or the middle part of the scan line), in order to calculate the specific field feature ', and in order to calculate the width of the low level of each scan line, you need to preset or calculate a wearing position threshold Hsync_Slicer_Thd 'When the gas number is lower than this cut When the threshold value Hsync_Slicer_Thd is used, the level can be regarded as a low level, and the feature detecting circuit 丨4 可 can be based on the time of the low level of the initial portion and/or the middle portion of each scanning line. The length (width) is compared - the predetermined number of scan lines is ^ corresponding to a particular field feature. The 〇_ algorithm disclosed in the present invention is based on the width of the corresponding portion of the predetermined number of scan lines to be turned off. ^ has a 敎 map (vertical synchronization feature), and further determine the type of field. Please refer to (4) to 9 ® 1 6 to 9 respectively show the feature detection circuit _ detection sweep Schematic diagram of the low-level width (time length) of the line. As shown in Fig. 6, the 'feature_circuit_ first multiplexes the composite video signal S cv B via a low-pass filter 6 to output a filtered signal Hsync-Slicer -In. The feature detecting circuit 14〇t sets an observation window at a specific portion (such as the starting portion and/or the middle portion) of each of the 20 201041373 of each scanning line; as shown in FIGS. 7 to 9, the viewing window It can be an observation window with a width of 2H. The degree may be a standard horizontal sync signal width. After determining the position of the viewing window, the feature detecting circuit 140 starts calculating a first reference value BackPorch_Val and a second reference value Hsync_Peak Val; and then according to the two references. Value to determine the required cutoff threshold

Hsync_Slicer_Thd; After the truncation threshold Hsync_Slicer_Thd is obtained, the feature detection circuit 140 compares the current scan line signal with the truncation threshold Hsync-Slicer_Thd to calculate that the current scan line signal is lower than the truncation threshold. The length of time Hsync_Slicer_Thd determines the corresponding feature (S, N or L). In an embodiment of the present invention, the feature detecting circuit 14 turns on a first reference area Bkporch_Val_Window in the observation window, where the first reference value BackPorch_Val is calculated. In addition, the feature detecting circuit mo ^ further determines the second reference value in a second reference region Hsync_PhErr_Window in the set viewing window.

Hsync—Peak-Val. For example, the feature detecting circuit 14 can calculate the average value of all sampling points in the first reference region Bkporch_Val_Window as the first reference value BackPorch_Val, and the lowest point in the second reference region Hsync_PhErr_Window. As the second reference value HSync_Peak_Va, after obtaining the first reference value BackPorch_Val and the second reference value Hsync_Peak_Val, the truncation threshold 21 is determined accordingly.

Hsync_Slicer_Thd. Please note that the foregoing process of calculating the first reference value and the second reference value to determine the truncation threshold Hsync_Slicer_Thd is for illustrative purposes only and is not one of the limitations of the present invention; any decision-reference threshold (intercept threshold) The value Hsync_Slicer_Thd) is a method/circuit for applying the vertical value to the horizontal synchronization signal width feature determination method/line in-line feature determination method provided by the present invention to perform vertical synchronization processing, and is within the scope of the present invention. For example, in an embodiment of the invention, the truncation threshold Hsync_Slicer_Thd can be determined according to the following formula:

Hsync_Slicer_Thd(n+1)=(Hsync_Peak_Val(n)+ BackProch_Val(n))/2; After determining the truncation threshold Hsync_Slicer_Thd of the current scan line, the feature detection circuit 140 can be based on the algorithm used (horizontal synchronization) The signal width feature judging method/in-line feature judging method is used to judge whether the initial portion/middle portion of each scanning line () is at a low level width, thereby detecting whether a predetermined number of scanning lines have a specific field feature. It is to be noted that the current truncation threshold Hsync_Slicer_Thd(n+1) of the scan line is obtained by averaging the first reference value BackPorch_Val(n) of the previous scan line and the second reference value Hsync_Peak_Val(n). In another embodiment, the truncation threshold Hsync_Slicer_Thd of the scan line may also be set to a predetermined value. Referring to FIG. 7, in the embodiment, the width of the scan line signal lower than the threshold value Hsync-Slicer_Thd of the section 22 201041373 is marked as St, then the gate is

St is less than 1.25H (as described above, when the width of the observation window is Η again). . . 8ι. is greater than 0.75 ’, then the feature width at this time is determined to be '’Ν,. Referring to FIG. 8, in this embodiment, the width of the scan line signal threshold Hsync_Slicer-Thd is marked as &, then the county presses Ο Ο

St is larger than L25H (as described above, the width of the observation window is two or two, and the feature width is "L"." When 0.25H is judged, the feature width at this time is "s". Said, through the feature detection circuit (10) = the characteristic sequence of the scan line, according to the line = the predetermined algorithm used to enter (four) the operation of the money step "wrong or inter-line knowledge and feature width" S",,, n ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, And the modifications, all = examples, the scope of patents according to the present invention is within the scope of the present invention. 23 201041373 [Simple Description of the Drawings] FIG. 1 is a schematic diagram of an embodiment of a video processing circuit according to the present invention. Figure 2 is a schematic diagram of a composite video signal conforming to the National Television (NTSC) System Committee standard. Figure 3 is a schematic diagram of a composite video signal conforming to the European standard progressive backward (PAL) standard.

Fig. 4 is a flow chart showing the operation of the vertical synchronization detecting circuit of the present invention using the horizontal synchronizing signal width characteristic judging method. Fig. 5 is a flow chart showing the operation of the in-line feature judging method for the vertical sync inversion circuit of the present invention. Fig. 6 is a view showing the first embodiment of the low-level width (time length) of the characteristic detecting circuit_scanning line of the present invention. Fig. 7 is a view showing a second embodiment of the low-level width (time length) of the characteristic_circuit_scanning line of the present invention. Fig. 8 is a schematic view showing a third embodiment of the feature detecting circuit _ Sweeping low-level width of the present invention. Fig. 9 is a view showing a fourth embodiment of the feature_circuit_such as the low-order length of the line) of the present invention. [Main component symbol description] 100 Video processing system 24 201041373 110 Horizontal synchronization detection circuit 120 Vertical synchronization processing circuit 130 Signal processing unit 140 Feature detection circuit 150 Vertical synchronization judgment circuit 160 Scan line number circuit 610 Low-pass waver Ο 25

Claims (1)

201041373 VII. Application for patents: 1. A vertical synchronization method for detecting a composite video signal. The vertical synchronization processing method includes: & a predetermined number of scans is required to have a specific field Number of turns = When the sweep line has the characteristics of the particular field, the composite video is encoded 'generating-sweeping line coded signal; and 』 /T field line editing signal and the specific field feature are judged The field outputs a vertical sync confirmation signal. And the method of claim 4, wherein the sweeping total number corresponding to one of the specific field features is calculated according to the sweep code and the map field feature to determine the correct map field type. ❹3 Special, the green, the shot, and the scale of the field described in the first item are characterized by the corresponding low-level time width of the beginning of the broom line: Λ the method described in item 3, where The window of the predetermined number of scan lines ϋ the low-level time width is the time width of one of the initial portions to observe the threshold value below one intercept. Such as the scope of patent application! The method of the present invention, wherein the middle portion of the predetermined number of scan lines respectively has a corresponding lower level of 5 Hz. The method of claim 5, wherein the middle portion of the predetermined number of scan lines Each has a low-level time width which is the time width of one of the middle portions of the observation window that is lower than a cut-off threshold. 7. The method of claim 1, wherein the composite video signal conforms to the National Television System (National NTSC) or Progressive Phase Inversion (PAL) standard. 8. A vertical sync detection circuit for receiving a composite video signal, the vertical sync detection circuit is coupled to a horizontal sync detection circuit for receiving a sample point signal and a horizontal sync confirmation signal, the vertical The synchronization processing circuit includes: a feature detection circuit, according to the sampling point signal and the horizontal synchronization confirmation signal, sequentially determining whether a predetermined number of scan lines in the composite video signal have a specific field feature; And encoding, according to the sampling point signal, the horizontal synchronization confirmation signal and the determination result of the feature detecting circuit, the scanning lines of the composite video signal to generate a scanning line encoding signal; and a vertical synchronization determining circuit, according to The scan line encodes the signal and the judgment result of the feature detection circuit to determine the field type and outputs a vertical sync confirmation signal. 9. The circuit of claim 8, wherein the vertical synchronization determining circuit 27 201041373=calculates the pair & the specific field based on the scan line coded signal and the determination result of the feature detection circuit Feature - The total number of scan lines for the correct type of field. The circuit described in item 8, wherein the fine field characteristic is " the initial portion of the scan number of the pre-existing number has a corresponding fresh time width. Ο G U. The circuit of claim H), wherein the initial portion of the number of scan lines is less than the time width of the cut-off threshold in the fa1 wide (four) window. Observation 12. The circuit of claim 8, wherein the specific field feature is the predetermined number of swept towels. 13. The circuit of claim 12, wherein the inter-I portion of the predetermined number of scan lines respectively has a low-level time width which is one of the middle portions thereof, and is less than a truncation threshold. The time width of the value. 14. The circuit of claim 8, wherein the composite video signal is a standard of the National Television System Committee (Nati〇nai ntsc) or Progressive Phase Inversion (PAL). The circuit of claim 8, wherein the vertical synchronization judging circuit determines the correct field type of 28 201041373 according to the scan line coded signal and the judgment result of the feature detection circuit. The scan line numbering circuit is capable of encoding correction. Eight, schema 29