KR20080060961A - Image display apparatus having detecting about kinds of field and control method thereof - Google Patents

Abstract

A display device having a function of detecting a type of a field and its control method are provided to accurately determine a type of a field if there is a change in a synchronous signal due to surroundings, to thus prevent screen image sparkles or a screen image interruption. A field analyzing unit determines whether the type of the certain number of sequentially inputted fields are the same(S410). If the types of fields are the same, the field analyzing unit stores the type of a final field in a storage unit(S420). The field analyzing unit determines whether a type of a previous field stored in the storage unit and a type of a subsequently inputted field are different(S430). If the types of the fields are different, the field analyzing unit checks the position of a synchronous signal(S440). The field analyzing unit determines whether the synchronous signal is positioned at a search window having a certain interval from the center among pulses constituting a horizontal synchronous signal(S450). If the synchronous signal is positioned at the search window, the field analyzing unit outputs a current field signal based on the type of the previous field(S460).

Description

Image display apparatus having detecting about kinds of field and control method

1A illustrates a general synchronization signal;

1B is a view showing the change of the synchronization signal according to the surrounding environment,

2 is a block diagram schematically illustrating a display apparatus including a field type detection function according to an embodiment of the present disclosure;

3 illustrates detection of a synchronization signal for field type determination according to an embodiment of the present invention; And

4 is a flowchart provided to explain a control method for detecting a field type according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

210: video signal input unit 220: video signal processing unit

230: separation unit 240: A / D conversion unit

250: field analysis unit 260: scaler unit

270: display unit 280: storage unit

290: control unit

The present invention relates to a display apparatus including a field type detection function and a control method thereof, and more particularly, to a display capable of reducing the occurrence of screen shuffling and screen breakup of an output image as the synchronization signal is changed by the surrounding environment. An apparatus and a method thereof are provided.

The analog video signal input from the display apparatus for receiving and outputting a video signal includes a composite video signal (CVBS (Composite Video Bust Synchronization)), an S-video signal, and a component signal.

The CVBS may be received through a tuner included in the display device or may be input through a VCR (Video Cassette Recorder, hereinafter VCR) connector.

The S-video signal may be input to the display device through a terminal that may be connected to a device such as a video home system (S-VHS) VCR or a digital versatile disc (DVD) having an S-video output. The S-video signal is composed of a luminance signal Y and a color signal C.

The component signal may be an RGB (Red, Green, Blue) signal or Y / Pb / Pr or Y / Cb / Cr type and may be input to the display device through a terminal which may be connected to a device such as a computer.

The input analog video signal includes a synchronization signal for identifying an input video format and for performing a display suitable for the format. In particular, the synchronization signal includes a horizontal synchronization signal for notifying the start of each field and a vertical synchronization signal for notifying the start of each frame, and the type of the input field may be determined according to the position of the vertical synchronization signal based on the horizontal synchronization signal. have.

1A and 1B show a conventional synchronization signal. Referring to FIG. 1A and FIG. 1B, FIG. 1A shows a phase at a distance apart from the horizontal sync signal 120 by δ with respect to the center (1H / 2) of one period of the horizontal sync signal 120. A diagram illustrating the vertical synchronization signal 110 to be changed.

In determining the type of the field, if the position of the horizontal synchronizing signal 120 and the vertical synchronizing signal 110 is δ> 1H / 2, the input field is determined as the top field, and the horizontal synchronizing signal 120 and the vertical synchronizing are performed. If the position of the signal 110 is δ <1H / 2, the input field is determined as the bottom field.

These analog video signals may be changed in the horizontal synchronizing signal and the vertical synchronizing signal by the surrounding environment. In particular, in the case of a VCR, a phenomenon in which the horizontal synchronizing signal and the vertical synchronizing signal are changed by the recording method, the deck speed, or the like is severely generated.

In addition, the display device displaying the analog image signal may cause an error in determining the type of field according to the change of the horizontal synchronizing signal and the vertical synchronizing signal.

1B is a diagram in which the horizontal synchronizing signal and the vertical synchronizing signal are changed by the surrounding environment.

Referring to FIG. 1B, the vertical synchronization signal 110 ′ is shifted to the left by ε by the surrounding environment from the existing vertical synchronization signal 110. In particular, the vertical synchronizing signal 110 'whose phase is changed at a distance apart from the horizontal synchronizing signal 120 by δ + ε is located on the left side of the horizontal synchronizing signal 120 at the left side of the horizontal synchronizing signal 120. It is determined that the change.

In particular, when the VCR operates in the stop mode and only one field is output, the display apparatus may incorrectly determine the type of the field and thus may not accurately determine the type of the field, which may result in screen jamming and screen truncation.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a display apparatus and a method for reducing the occurrence of screen distortion and screen dropping of the output image as the synchronization signal is changed by the surrounding environment. In providing.

According to an aspect of the present invention, there is provided a display apparatus including a second synchronization device between a storage unit in which information on a type of a previous field is stored, and pulses constituting a first synchronization signal for a current field. If the change position of the logic level of the signal is located in a predetermined section, the type of the current field includes a field analyzer to determine that the type of the current field is the same as the type of the previous field stored in the storage unit.

The predetermined section may be a section within a predetermined distance from the center of the pulses constituting the first synchronization signal.

In addition, if it is determined that the types of the predetermined number of fields sequentially input are the same, the field analyzer may store the types of the fields as the type of the previous field in the storage unit.

The first synchronization signal may be a horizontal synchronization signal, and the second synchronization signal may be a vertical synchronization signal.

On the other hand, the method of detecting the correct type of field determines whether the change position of the logic level of the second synchronous signal is located in a predetermined section among the pulses constituting the first synchronous signal for the current field and the change position is the predetermined position. If it is located in the section includes the step of determining that the type of the current field is the same as the type of the previous field.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

2 is a block diagram schematically illustrating a display apparatus according to an exemplary embodiment.

Referring to FIG. 2, a display apparatus according to an exemplary embodiment of the present invention includes an image signal input unit 210, an image signal processor 220, a display unit 270, a storage unit 280, and a controller 290.

The video signal input unit 210 receives one of a video signal such as a composite video signal (CVBS), an S-video signal, and a component signal and transmits it to the video signal processor 220.

The image signal processor 220 divides the received image signal into a field signal and a synchronization signal, and provides the display unit 270 with an RGB signal including each field signal in one frame according to the synchronization signal.

The image signal processor 220, which performs such a function, includes a separator 230, an A / D converter 240, a field analyzer 250, and a scaler 260.

The separating unit 230 separates the transmitted image signal into a field signal and a synchronization signal. In particular, the separating unit 230 separates the field signal (Y, Cb / Cr) and the synchronization signal (horizontal synchronization signal, vertical synchronization signal) and transmits it to the A / D conversion unit 240.

The A / D converter 240 converts the field signal and the synchronization signal transmitted from the separator 230 into a digital signal and transmits the digital signal to the field analyzer 250.

The field analyzer 250 determines the field type of the field signal transmitted through the horizontal / vertical synchronization signal from the A / D converter 240 and transmits the field type information to the controller 290. In particular, the field analyzer 250 determines the type of field according to the logic level change position of the vertical sync signal based on the horizontal sync signal, and classifies the field into a top / bottom field (odd / even field) according to the field type.

In more detail, when it is determined that the types of the predetermined number of fields sequentially input are the same, the field analyzer 250 stores the type of the field in the storage 280. When the field type is changed due to the change of the position of the synchronization signal, the control unit 290 detects the logic level of the vertical synchronization signal among the pulses constituting the horizontal synchronization signal for the current field. If it is determined that the change position with respect to the predetermined section, it is determined that the same as the type of the previous field stored in the storage unit 280 and controls to output the same image as before.

In addition, when the type of the predetermined number of fields sequentially input by the field analyzer 250 is the same, a detailed description of the process of determining the type of the field through the search window in determining the type of the field to be transmitted later will be given. It will be described later.

The scaler 260 combines the field signals transmitted according to the field types determined by the field analyzer 250 into one frame, and displays the RGB image signals adjusted to the size of the display unit 270. To pass on.

The display unit 270 displays the RGB image signal transmitted from the scaler 260.

The storage unit 280 may store a control algorithm for activating the setting and control of the display apparatus. In addition, the storage unit 280 may temporarily store the field signal and the type of the field.

The controller 290 controls the overall operation of the display apparatus such that the input image signal is normally displayed using the field signal stored in the storage unit 280 and the type of the field information. In particular, the controller 290 controls the scaler 260 to combine the field signals into one frame according to the type of the field determined by the field analyzer 250 so that a normal output is performed.

3 is a diagram illustrating detection of a synchronization signal for determining a field type according to an embodiment of the present invention.

3 includes the modified synchronization signal as shown in FIG. 1B and includes a search window 130 having a predetermined period α from the center 1H / 2 between the pulses constituting the horizontal synchronization signal 120.

If it is determined that the types of the predetermined number of fields sequentially input are the same, the field analyzer 250 stores the field type information of the last field among the predetermined number of fields in the storage unit 280. In addition, the field analyzer 250 controls the fields to be input later through the search window 130 to determine the type of the field.

In particular, when it is determined that the changed vertical synchronization signal 110 ′ has changed the logic level in the search window 130 section, the field analyzer 250 is the same field type as the field type information stored in the storage unit 280. Control to be judged.

Thus, the controller 290 controls the transfer of the previous field type information stored in the storage 280 to the scaler 260 to output a normal image.

Hereinafter, a control process of the display apparatus including the field type detection function illustrated in FIG. 2 will be described in detail with reference to FIG. 4. 4 is a flowchart provided to explain a control method for detecting a field type according to an embodiment of the present invention.

Referring to FIG. 4, the field analyzer 260 determines whether the types of the predetermined number of fields sequentially input are the same (S410).

If the types of the predetermined number of fields are output as the same (S410-Y), the field analyzer 250 stores the type of the last field among the predetermined number of fields in the storage unit 280 (S420).

The field analyzer 250 determines whether the type of the previous field stored in the storage unit 280 is different from the type of the field input thereafter (S430).

If the field type information is different (S430-Y), the field analyzer 250 checks the position of the synchronization signal (S440).

The field analyzer 250 determines whether the position of the synchronization signal is located in the search window 130 having a predetermined period α from the center 1H / 2 between the pulses constituting the horizontal synchronization signal (S450).

If the position of the synchronization signal is located in the search window 130 (S450-Y), the field analyzer 250 determines that the type of the current field is the same as the type of the previous field stored in the storage unit 280, and stores it. The current field signal is output based on the type of the previous field stored in the unit 280 (S460).

If the location of the synchronization signal is not located in the search window 130 (S450-N), the field analyzer 250 determines that the type of the field is detected and outputs the current field signal based on the type of the current field. (S470).

As described above, according to the present invention, when there is a change in the synchronization signal due to the surrounding environment, it is possible to accurately determine the type of the field, thereby reducing the occurrence of screen jamming and screen dropping of the output image. Thus, a stable and clean image can be provided to the user.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the specific embodiments described above, but the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

Claims (5)

A storage unit for storing information on the type of the previous field; And If the change position of the logic level of the second synchronization signal is located in a predetermined section among the pulses constituting the first synchronization signal for the current field, the type of the current field is the same as the type of the previous field stored in the storage unit. And a field analyzer to determine that it is determined. The method of claim 1, And the predetermined section is a section within a predetermined distance from a center of pulses constituting the first synchronization signal. The method of claim 1, The field analysis unit, If it is determined that the types of the predetermined number of fields sequentially input are the same, And storing the types of the fields as the type of the previous field in the storage unit. The method of claim 1, And the first synchronization signal is a horizontal synchronization signal, and the second synchronization signal is a vertical synchronization signal. Determining whether a change position of a logic level of the second synchronization signal is located in a predetermined section among pulses constituting the first synchronization signal for the current field; And And determining that the type of the current field is the same as the type of the previous field when the change position is located in the predetermined section.

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