JPH10333627A - Picture signal discriminating circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture signal discriminating circuit that carry out the signal discrimination by judging to which signal out of a plurality of comparison object signals the input picture signal is most similar, so that the impossibility of discrimination is prevented. SOLUTION: Synchronous characteristic detecting circuits 1, 2, 3 detect and classify horizontal and vertical synchronous signals in accordance with the characteristics such as the frequency, form, and polarity. Image characteristic detecting circuits 4, 5 detect and classify a picture signal in accordance with the characteristics such as the blanking time, and phase. Weighted multiplication circuits 7 (7a to 7e) compare the respective characteristics detected and classified by the synchronous characteristic detecting circuits and the image characteristic detecting circuits with a prescribed characteristic for carrying out weighting in accordance with the degree of approximation, and a similarity degree adding circuit 8 calculates the degree of similarity on the basis of the degree of approximation for each characteristic. On the basis of the similarity, a discriminating circuit 6 compares it with a predetermined discriminating element and the result of discrimination is output. By the result of discrimination, various picture signal characteristics are automatically enabled to be discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal discriminating circuit, for example, a video signal discriminating circuit applied to a video display device and capable of selecting an optimum adjustment state by using discrimination information of a video signal.

[0002]

2. Description of the Related Art Conventionally, a video signal discriminating circuit is configured as a discriminating circuit for receiving various video signals and discriminating the video signals. This video signal discrimination circuit is applied and used in a video display device or the like. For example, in order to automatically follow a variety of video signals and display various video signals in an optimal state, a video signal determination circuit is used to accurately determine the video signals.

In order to accurately determine a video signal, it is necessary to detect and determine a unique element of the video signal. These determination methods include a horizontal and vertical synchronization frequency, a synchronization mode determination for determining whether the synchronization signal is separated from the video signal, and whether the horizontal and vertical synchronization signal is separated, and whether the synchronization signal is positive or negative. There are a sync polarity determination for determining whether or not there is, and a method for detecting a relative position between a time of a non-picture portion in a video signal and a synchronization signal.

FIG. 5 shows an example of the configuration of a video signal discriminating circuit according to a first conventional example. The video signal discriminating circuit of the first conventional example shown in FIG. 5 includes a horizontal / vertical synchronous frequency detecting circuit 1 for detecting horizontal and vertical synchronous frequencies, and whether an input synchronous signal is a horizontal / vertical separation type signal or a decoding synchronous signal. A synchronous form detection circuit 2 for detecting whether the signal is of a type added to the video signal, a synchronization polarity detection circuit 3 for detecting the polarity of the synchronization signal, and a block for detecting the time of a non-picture portion in the video signal. A ranking time detection circuit 4, a video phase detection circuit 5 for detecting a relative position between a video display portion and a synchronization signal, and a video signal input based on detection results of the synchronization frequency detection circuits 1 to 5 And a determination circuit 16 for determining the state.

Next, the operation of the video signal discriminating circuit of the first prior art will be described. FIG. 7 shows an example of data for detecting a signal discriminating element between an input signal and a signal to be compared.

It is assumed that the discriminating circuit 16 has a plurality of discriminating elements for signals to be compared (signals B and C) set in advance as shown in FIG. Now, it is assumed that the signal A is input, and the detection results output from the detection circuits (1, 2, 3) for each discrimination element are similarly as shown in FIG. These are discrimination circuits 16
To be compared with the discriminant elements of the respective signals to be compared in FIG. Based on the result of the comparison, a signal that matches in all the discrimination elements is selected from the comparison target signals, and it is determined which input comparison signal the input signal corresponds to. In the first conventional example, since the detection result of the signal A matches all the discrimination factors of the signal C, the signal C is selected as the discrimination result of the signal A.

In addition to the method of setting the comparison target signal shown in FIG. 7 in advance, a method of storing a discriminating element of an arbitrary signal is also conceivable. FIG. 6 shows a second example of the configuration of the video signal discriminating circuit of this variation. In the video signal discriminating circuit shown in FIG. 6, the discriminating circuit 26 is generally composed of a CPU circuit controlled by software and a memory circuit 27 for storage.

FIG. 8 shows a flowchart of a control procedure in signal discrimination of the first conventional example. According to the signal discrimination of Conventional Example 1 in FIG. 8, a new video signal is input (S11), each signal discrimination element is detected (S12), and the presence or absence of a corresponding signal is checked (S13). Performs the necessary correction on the corresponding signal (S14), and the signal determination ends. However, if there is no such signal, the signal cannot be determined.

Conventionally, in discriminating a video signal, discrimination is made based on differences in the horizontal and vertical synchronization frequencies, the form and polarity of the synchronization signal, and the time and position of a non-picture portion in the video signal, which are factors for the discrimination. Is generally performed by detecting and discriminating a match / mismatch between these elements of the input video signal and the discrimination element of the video signal to be compared. In this case, it is determined that the input video signal is the same as the video signal to be compared when all the determination elements match.

As a prior art example similar to the present invention in the technical field, a "multi-scan display monitor" disclosed in Japanese Patent Application Laid-Open No. Hei 7-177439 of the related art 2 divides a horizontal synchronizing signal to a predetermined frequency, and divides the signal into the same frequency. And discloses a technique for counting the pulse signal and dividing the horizontal frequency.

The "horizontal frequency mode discriminating circuit" disclosed in Japanese Unexamined Patent Application Publication No. 6-90377 of the prior art 3 is a simple circuit for simplifying the horizontal frequency mode in a multi-scan monitor using a plurality of video signals having different horizontal frequencies as input sources. A discrimination circuit that can be discriminated by a circuit having a simple configuration is disclosed.

As a method of discriminating a video signal, a method of counting a synchronous frequency of one of horizontal and vertical or both by a counter circuit as in the above-described conventional example 2 and discriminating the signal is used. As in Example 3, a method of converting the synchronization frequency into a frequency and a voltage and discriminating a signal by a voltage comparator circuit is generally used.

[0013]

However, in the methods of the above-mentioned conventional examples 1 to 3, only those in which all the discriminating elements match can be selected. For this reason, even if only some of the discrimination elements are different, it is inevitable that the discrimination cannot be performed unless there is a match with all the other discrimination elements. Further, the method of determining whether or not these determination elements match those of the signal to be compared involves a problem that the signals that can be determined are limited.

Further, when discrimination is performed based on the coincidence of all discrimination elements, it is impossible to discriminate even very similar video signals in which only some of the discrimination elements are different. This is because if the number of discriminants is reduced so that similar video signals can be discriminated,
Since the number of video signals to be compared is reduced, the types that can be discriminated are reduced, and it becomes difficult to discriminate between similar signals. When the input video signal is similar to a plurality of comparison targets, there is a problem that a more similar signal cannot be specified from the corresponding comparison target signals. This is because similarity can be determined only by detecting the coincidence or non-coincidence of the discrimination elements, but the similarity cannot be detected.

The present invention provides a video signal discriminating circuit that discriminates a signal based on which of a plurality of input video signals is most similar among a plurality of comparison target signals and prevents the discrimination from being impossible. The purpose is to:

[0016]

In order to achieve the above object, a video signal discriminating circuit according to the present invention comprises: a synchronous feature detecting circuit for detecting and classifying a horizontal synchronizing signal and a vertical synchronizing signal according to predetermined characteristics; A video feature detection circuit for detecting and classifying each of the predetermined characteristics, and comparing each of the characteristics detected and classified by the synchronous feature detection circuit and the video feature detection circuit with a predetermined predetermined characteristic, and calculating an approximation of the predetermined characteristic. A weight multiplying circuit for weighting according to the degree, a similarity adding circuit for calculating the similarity based on the degree of approximation for each characteristic; And a discriminating circuit for outputting the signal, whereby the characteristics of various video signals can be automatically discriminated based on the discrimination result.

The synchronous feature detecting circuit includes a synchronous frequency detecting circuit for detecting the horizontal and vertical frequencies of the synchronous signal, a synchronous form detecting circuit for detecting the form of the synchronous signal, and a synchronous form detecting the polarity of the synchronous signal. Including a polarity detection circuit,
The video feature detection circuit may include a blanking time detection circuit that detects a time of a non-picture portion in the video signal, and a video phase detection circuit that detects a phase based on a position or the like of the video signal.

Further, the discrimination circuit includes a CPU circuit and a memory circuit, and performs comparison using preset software, and the predetermined characteristic and / or discrimination element are stored in a predetermined table. It is good to set in the format.

It is preferable that the information of the above-mentioned determination result can be utilized in various kinds of video signal processing devices or display devices.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a video signal discriminating circuit according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 and FIG. 4 show an embodiment of a video signal discriminating circuit of the present invention. FIG. 1 is a circuit configuration block diagram showing an embodiment of a video signal discrimination circuit of the present invention.
FIG. 4 is a flowchart showing a control procedure for signal discrimination.

The video signal discriminating circuit of the present embodiment shown in FIG. 1 has the same function as the conventional example, that is, a horizontal / vertical synchronous frequency detecting circuit 1 for detecting horizontal and vertical synchronous frequencies. A synchronization form detection circuit 2 for detecting whether the synchronization signal is a horizontal / vertical separation type signal, a decoding synchronization signal, or a type added to a video signal;
A synchronization polarity detection circuit 3 for detecting the polarity of the synchronization signal, a blanking time detection circuit 4 for detecting the time of a non-picture portion in the video signal, and a video phase detection circuit 5 for detecting a relative position between the video display portion and the synchronization signal. ,have.

Further, a discriminating circuit 6 for discriminating the input video signal based on the detection results from the synchronous frequency detecting circuit 1 to the video phase detecting circuit 5, weighting multiplication for weighting the detection output of each signal discriminating element A circuit 7, an adding circuit 8 for calculating the similarity by summing the results of the weighting and multiplying circuits 7, a synchronizing signal processing circuit 11 for synchronizing an externally input horizontal synchronizing signal and a vertical synchronizing signal, and a video signal processing circuit 1.
2 is configured.

In the connection relationship of the video signal discriminating circuits constituted by the above-described respective parts, the two output signals of the horizontal synchronizing signal and the vertical synchronizing signal of the synchronizing signal processing circuit 11 The circuit 2, the synchronization polarity detection circuit 3, the blanking time detection circuit 4, and the video phase detection circuit 5 are input to each unit. The video signal, which is an output signal of the video signal processing circuit 12, is input to the blanking time detection circuit 4 and the video phase detection circuit 5.

The output signals from the synchronous frequency detecting circuit 1, the synchronous form detecting circuit 2, the synchronous polarity detecting circuit 3, the blanking time detecting circuit 4, and the video phase detecting circuit 5 are supplied to respective weighting and multiplying circuits 7a to 7e. Is input to Output signals from each of the weighting multiplication circuits 7a to 7e are input to the similarity addition circuit 8, and output signals from the similarity addition circuit 8 are input to the determination circuit 6, and the determination result is output from the determination circuit 6. .

Next, an operation example of the video signal discriminating circuit of the present embodiment will be described. FIG. 2 shows a configuration example of detection data of a signal discriminating element of an input signal and a signal to be compared according to the present embodiment.

FIG. 2 shows an example of a configuration in which the discriminating elements are configured in a table format. The discrimination mode is an H / V separation type signal B, an H / V mixed type signal C, a discrimination value of 1/0, and a weighting coefficient.

FIG. 3 shows a configuration example of the similarity between the input signal and the signal to be compared in the present embodiment.

FIG. 3 shows a configuration example 2 in which the discriminating elements are configured in a table format as in FIG. The discrimination mode is defined as H / V separation type signal A, H / V separation type signal B, H / V mixed type signal C, similarity between signal A and signal B, and similarity between signal A and signal C. I have.

It is assumed that the discriminating circuit 6 has a plurality of discriminating elements for comparison signals set in advance as shown in Table 2. now,
Here, it is assumed that the signal A is input and the detection result output from each discriminant detection circuit is also as shown in FIG.

The signal A is compared with each of a plurality of signals to be compared and their discrimination elements, and the difference between them is detected. At the time of detection, weights individually set for each discrimination element are performed by the weight detection circuit 7 and output.
The results output from the weighting detection circuit 7 are summed up by the similarity addition circuit 8 and are expressed as the similarity between the input signal and the comparison target signal. In the present embodiment, the similarity between the signal A and each comparison target signal is represented as shown in FIG. In this case, the signal A is larger than the signal C in the signal C than the signal B.
Since the numerical value of the similarity between the signal A and the signal A is larger, the signal A is more similar to the signal C than the signal B, and the signal C is selected as the determination result.

According to the above-described embodiment, in the method of detecting only the coincidence or non-coincidence of each signal discriminating element and selecting the corresponding signal from the signals stored in advance, the signals other than the stored signals are selected. The disadvantage that the input cannot be discriminated when it is input is eliminated. In addition, the number of comparison target signals stored in advance so as not to be indistinguishable is increased, and the restriction on increasing the combination of horizontal and vertical frequencies is eliminated.
Accordingly, it is possible to flexibly cope with a demand for accuracy required in various devices to which the present video signal discriminating circuit is applied, for example, various kinds of video signal processing devices or display devices. Therefore, it is possible to eliminate the fact that the discrimination cannot be practically performed.

Further, in the present embodiment, even if the number of comparison target signals stored is small, the similarity between the newly input signal and each comparison target signal is obtained, and the closest signal is selected. Therefore, it is not impossible to determine. If the signal selected as the determination result is not acceptable, the currently input signal is newly stored and used as a comparison target signal, so that the range of selection of a signal to be input in the future can be expanded.

It is expected that the influence of each discrimination element on the actual display of an image will differ greatly depending on the difference in the image display element. For example, in an LCD display, the difference in the number of displayable pixels has a greater effect on the displayed image than in the horizontal and vertical synchronization frequencies. On the contrary, in a CRT display, the difference in the number of displayable pixels is greater than the information on the number of displayable pixels. It is considered that the frequency has a higher influence on the display.

In the present embodiment, the weighting coefficient set individually for each discrimination element can be changed according to the degree of influence of each discrimination element on signal discrimination due to a difference in image display element or the like. It is possible to respond.

FIG. 4 shows a flowchart of a control procedure in signal discrimination according to the present embodiment.

A plurality of sets of the horizontal and vertical frequencies, the form and polarity of the synchronization signal, the time and position of the non-picture portion in the video signal, which are the discrimination elements of the comparison target signal for determining the input video signal. It shall be stored. When a new video signal is input here (S1), each discriminant element of each signal is detected (S2), and each discriminant element is compared with one of the stored comparison target signals to obtain a difference. Then, weighting is performed in order from the element having the highest importance among the discrimination elements. In this weighting procedure, the one having the highest similarity is selected (S3), and the presence or absence of a problem in the selected signal is checked (S4). If there is no problem, necessary correction is performed on the corresponding signal (S3). S5). If there is a problem, the determination element is newly stored (S6).

After weighting according to the above procedure,
The obtained numerical values are summed to determine a similarity between the obtained signal and the comparison target signal. This similarity is calculated for each signal to be compared, one having the highest similarity is selected, and this is determined as the corresponding signal.

According to the above procedure, when it is determined that the result of displaying the video signal is not a problem, the result of the determination is maintained thereafter. If there is a problem in the result, each of the discrimination elements is newly stored for this signal, so that it can be used as a discrimination target of a newly input video signal. Also,
The most similar comparison target signal is selected based on the similarity calculated by the discrimination element of the newly input video signal, so that the discrimination cannot be disabled. Also,
Only when there is a problem in the result of displaying the video, it is only necessary to newly store each discrimination element of the corresponding signal, and it is not necessary to individually store all the elements of the input signal.

The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the spirit of the present invention.

[0040]

As apparent from the above description, the video signal discriminating circuit of the present invention detects and classifies the horizontal synchronizing signal and the vertical synchronizing signal according to predetermined characteristics, and detects and classifies video signals according to predetermined characteristics. I do. Each of the detected and classified characteristics is compared with a predetermined characteristic, weighted based on the degree of approximation to the predetermined characteristic, and the similarity is calculated based on the degree of approximation for each characteristic. Based on the degree of similarity, a comparison is made with a predetermined discrimination element, and the result of the comparison is output.

According to the present apparatus, no matter what video signal is input, the similarity between a plurality of comparison target signals stored in advance is calculated, whereby the comparison target signal having the highest similarity is calculated. Can always be selected. Therefore, no matter which video signal is input, it is not impossible to determine. Further, the weighting coefficient of each discrimination element can be arbitrarily changed, and the degree of influence on the discrimination result of the signal discrimination element can be changed.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing an embodiment of a video signal discrimination circuit of the present invention.

FIG. 2 is a diagram illustrating an example of detection of a signal discriminating element of an input signal and a signal to be compared according to the present invention.

FIG. 3 is a diagram illustrating an example of a similarity between an input signal of the present invention and a comparison target signal.

FIG. 4 is a flowchart of a control procedure for signal discrimination in the present invention.

FIG. 5 is a circuit block diagram showing a configuration example 1 of a video signal discriminating circuit of Conventional Example 1.

FIG. 6 is a circuit block diagram showing a second example of the configuration of the video signal discrimination circuit of the first conventional example.

FIG. 7 is a diagram illustrating an example of detection of a signal discriminating element of a conventional input signal and a signal to be compared.

FIG. 8 is a flowchart of a control procedure in a conventional signal discrimination. [Brief description of drawings]

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Synchronization frequency detection circuit 2 Synchronization form detection circuit 3 Synchronization polarity detection circuit 4 Blanking time detection circuit 5 Video phase detection circuit 6 Discrimination circuit 7 Weighting multiplication circuit 8 Addition circuit 11 Synchronization signal processing circuit 12 Video signal processing circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 17/00 H04N 17/00 F

Claims (6)

[Claims] A synchronous feature detection circuit that detects and classifies a horizontal synchronization signal and a vertical synchronization signal according to predetermined characteristics; a video feature detection circuit that detects and classifies a video signal according to predetermined characteristics; A weighting multiplying circuit that compares each characteristic detected and classified by the video feature detection circuit with a predetermined characteristic and performs weighting according to the degree of approximation with the predetermined characteristic; A similarity addition circuit that calculates a similarity based on the degree; and a determination circuit that compares the similarity with a predetermined determination element based on the similarity and outputs the compared determination result. A video signal discriminating circuit characterized in that characteristics of various video signals can be automatically discriminated. 2. The synchronous feature detecting circuit includes: a synchronous frequency detecting circuit for detecting horizontal and vertical frequencies of a synchronous signal; a synchronous form detecting circuit for detecting a form of the synchronous signal; and a synchronous polarity for detecting a polarity of the synchronous signal. 2. The video signal discrimination circuit according to claim 1, further comprising a detection circuit. 3. A blanking time detecting circuit for detecting a time of a non-picture portion in a video signal,
3. The video signal discrimination circuit according to claim 1, further comprising a video phase detection circuit for detecting a phase based on a position of the video signal and the like. 4. The image according to claim 1, wherein the determination circuit includes a CPU circuit and a memory circuit, and the comparison is performed by software set in advance. Signal discrimination circuit. 5. The video signal discriminating circuit according to claim 1, wherein the predetermined characteristics and / or discriminating elements are set in a predetermined table format. 6. The video signal according to claim 1, wherein the information of the determination result can be used in a variety of video signal processing devices or display devices. Discrimination circuit.