Method and apparatus for transmitting video signal

Provided is a method and apparatus for transmitting a video signal. The video signal transmission method and apparatus receives a digital video signal from a video sensor, reconfigures the digital video signal by adaptively adjusting at least one of the number of horizontal blank samples and the number of vertical blank lines of the digital video signal so that the digital video signal corresponds to a video standard, converts the reconfigured digital video signal to an analog video signal, and transmits the analog video signal.

CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. National Stage of PCT application PCT/KR2015/001906 filed in the Korean language on Feb. 27, 2015, and entitled “METHODANDAPPARATUSFORTRANSMTITINGVIDEOSIGNAL,” which claims priority to Korean application KR 10-2014-0166380, filed on Nov. 26, 2014, which applications are each hereby incorporated herein by reference in their entireties.

TECHNICAL FIELD

Example embodiments relate to technology for transmitting a video signal, and more particularly, to technology for transmitting an analog video signal by converting a digital video signal to the analog video signal.

RELATED ART

A video transmission method may include a method of using an open circuit and a method of using a closed circuit. Since a video transmission method using an open circuit is to transmit video signals to a plurality of unspecific users, a standardized scheme may be employed to transmit a video. On the other hand, since a video transmission method using a closed circuit is to transmit a video signal only to a specific user, only the specific user may be aware of a video signal transmission scheme.

In general, a composite signal used in a closed-circuit system follows a standard method about an analog color television (TV). Since the standard method uses a limited frequency band, an alternating color issue and a luminance inclusion issue may occur.

Korean Patent Publication No. 10-2006-0063723, published on Dec. 5, 2005, discloses the invention relating to a video signal processing device and a video signal transmission method. This invention may be applied to display a national television system committee (NTSC)-based video signal, thereby effectively avoiding displaying of an unnatural edge and efficiently processing a video signal having a relatively high frame frequency through a simple configuration. In the published invention, a center value of a temporal axis in a single frame of a color difference signal is set to be closest to a center value of a temporal axis in a plurality of frames of a luminance signal corresponding to the color difference signal, and the single frame of the color difference signal is allocated to the plurality of frames of the luminance signal.

DETAILED DESCRIPTION

Technical Subject

Example embodiments provide an apparatus and method for transmitting a video signal

Example embodiments also provide an apparatus and method for transmitting an analog video signal by converting a digital video signal to the analog video signal.

Solution

According to an aspect, there is provided a video signal transmission method including receiving a digital video signal from a video sensor, reconfiguring the digital video signal by adaptively adjusting at least one of the number of horizontal blank samples and the number of vertical blank lines of the digital video signal so that the digital video signal corresponds to a video standard, converting the reconfigured digital video signal to an analog video signal, and transmitting the analog video signal.

The video signal transmission method may further include generating the digital video signal using the video sensor.

The generating of the digital video signal may include receiving information about a resolution of a digital video, and generating the digital video to correspond to the resolution.

The reconfiguring may include determining at least one of the number of horizontal blank samples, the number of vertical blank lines, a frame rate, and a scanning scheme based on the received digital video signal, and reconfiguring the digital video signal based on at least one of the number of horizontal blank samples and the number of vertical blank lines.

The converting may include determining a system frequency of the analog video signal based on at least one of the number of horizontal blank samples, the number of vertical blank lines, and the frame rate, and generating the analog video signal using the system frequency.

The system frequency may be determined by multiplying the number of samples in a single horizontal line, the number of vertical lines, and the frame rate.

The reconfiguring of the digital video signal based on at least one of the number of horizontal blank samples and the number of vertical blank lines may include adjusting the number of samples in each horizontal line of the digital video signal to include the number of horizontal blank samples, and adjusting the number of vertical lines of the digital video signal to include the number of vertical blank lines.

The determined number of horizontal blank samples may be an even number.

The reconfiguring of the digital video signal based on at least one of the number of horizontal blank samples and the number of vertical blank lines may include reconfiguring a Y-channel and a CbCr-channel of the digital video signal based on at least one of the number of horizontal blank samples and the number of vertical blank lines.

The reconfiguring of the digital video signal based on at least one of the number of horizontal blank samples and the number of vertical blank lines may include reconfiguring the digital video signal based on the scanning scheme.

The reconfiguring may include displaying additional data on preset area of a vertical blank line of the reconfigured digital video signal.

The converting may include calculating a horizontal frequency of the analog video signal, calculating a subcarrier frequency based on the horizontal frequency, and converting the digital video signal to the analog video signal based on the horizontal frequency and the subcarrier frequency.

The reconfiguring may include displaying additional data on preset area of a vertical blank line of the reconfigured digital video signal.

The converting may include calculating a horizontal frequency of the analog video signal, calculating a subcarrier frequency based on the horizontal frequency, and converting the digital video signal to the analog video signal based on the horizontal frequency and the subcarrier frequency.

The converting of the digital video signal to the analog video signal based on the horizontal frequency and the subcarrier frequency may include modulating a color difference signal of the analog video signal based on the subcarrier frequency.

According to another aspect, there is provided an apparatus for transmitting a video signal, the apparatus including a communicator configured to receive a digital video signal from a video sensor, and to transmit an analog video signal, and a processor configured to reconfigure the digital video signal by adaptively adjusting at least one of the number of horizontal blank samples and the number of vertical blank lines of the digital video signal so that the digital video signal corresponds to a video standard, and to convert the reconfigured digital video signal to the analog video signal.

The processor may be further configured to determine at least one of the number of horizontal blank samples, the number of vertical blank lines, a frame rate, and a scanning scheme based on the received digital video signal, and to reconfigure the digital video signal based on at least one of the number of horizontal blank samples and the number of vertical blank lines.

The processor may be further configured to display additional data on a preset area of a vertical blank line of the reconfigured digital video signal.

The processor may be further configured to calculate a horizontal frequency of the analog video signal, to calculate a subcarrier frequency based on the horizontal frequency, and to convert the digital video signal to the analog video signal based on the horizontal frequency and the subcarrier frequency.

Effect

According to example embodiments, there may be provided a video signal transmission apparatus and method.

Also, according to example embodiments, there may be provided an apparatus and method that may transmit a video signal by converting a digital video signal to an analog video signal.

Also, according to example embodiments, there may be provided an apparatus and method that may adaptively reconfigure digital video signal having various resolutions.

Hereinafter, some example embodiments will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings refer to like elements throughout the present specification.

Various modifications may be made to the example embodiments. However, it should be understood that these embodiments are not construed as limited to the illustrated forms and include all changes, equivalents or alternatives within the idea and the technical scope of this disclosure.

Hereinafter, the term “digital video” may be interpreted as the same meaning as the term “digital video data” or “digital video signal”. The term “analog video” may be interpreted as the same meaning as the term “analog video signal”.

FIG. 1illustrates an example of a flow of generating an analog video signal according to example embodiments.

A video sensor may generate an image by photographing a scene. The image refers to a digital frame generated using a digital method. A plurality of frames constitutes a digital video. That is, the video sensor may generate a digital video by photographing a plurality of scenes.

According to an aspect, the video sensor may be an imaging device used for a closed circuit television (CCTV) system. For example, the video sensor may be a monitoring camera.

A method of providing the generated digital video to a receiver may include a digital method and an analog method. The digital method may directly transmit the digital video. The analog method may convert a digital video signal to an analog video signal, and may transmit the analog video signal.

A method of transmitting the digital video using the analog method will be described with reference toFIGS. 2 through 14.

FIG. 2is a block diagram illustrating a configuration of a video signal transmission apparatus according to example embodiments.

Referring toFIG. 2, a video signal transmission apparatus200includes a communicator220and a processor230. The video signal transmission apparatus200may further include a video sensor210and a storage240.

The video sensor210may correspond to the video sensor ofFIG. 1. For example, the video sensor210may be an imaging device using a complementary metal-oxide semiconductor (CMOS).

The communicator220may be connected to an external device to transmit and receive data.

The processor230may process data received at the communicator220or data stored in the storage240.

The storage240may store data received at the communicator220or data processed at the processor230.

The video sensor210, the communicator220, the processor230, and the storage240will be described with reference toFIGS. 3 through 14.

FIG. 3is a flowchart illustrating a video signal transmission method according to example embodiments.

In operation310, the video sensor210may generate a digital video by photographing a scene. The video sensor210may generate the digital video based on a sampling clock. The digital video may include one or more frames.

For example, the video sensor210may photograph a scene at a variety of resolutions. As another example, the video sensor210may convert the photographed digital video based on a variety of resolutions.

For example, a variety of resolutions may include 1024×600, 1280×1024, and 1280×768.

In operation320, the communicator220may receive a digital video signal from the video sensor210. The digital video signal may be a signal or data about the digital video.

In operation330, the processor230may reconfigure the digital video signal so that the digital video signal corresponds to a video standard. For example, the processor230may reconfigure the digital video signal by adaptively adjusting at least one of horizontal blank samples and the number of vertical blank lines of the digital video signal so that the digital video signal corresponds to the video standard.

The video standard may be preset. For example, the video standard may be set based on a coaxial cable through which an analog video signal is transmitted. The video standard may be preset not to exceed a transmittable maximum bandwidth of the coaxial cable.

A method of reconfiguring the digital video signal will be described with reference toFIGS. 5 through 10.

In operation340, the processor230may convert the reconfigured digital video signal to the analog video signal.

A method of converting the reconfigured digital video signal to the analog video signal will be described with reference toFIGS. 11 through 14.

FIG. 4is a flowchart illustrating a method of generating a digital video signal according to example embodiments.

In operation410, the video sensor210may receive information about a resolution of the digital video.

According to an aspect, the video sensor210may receive information about the resolution through the communicator220. For example, a user of a CCTV system may transmit information about the resolution to the communicator220through a video signal reception apparatus connected to the video signal transmission apparatus200.

In operation420, the video sensor210may generate the digital video to correspond to the resolution.

Through operations410and420, the video sensor210may generate the digital video having a variety of resolutions.

FIG. 5is a flowchart illustrating a method of reconfiguring a digital video signal according to example embodiments.

In operation510, the processor230may determine at least one of the number of horizontal blank samples, the number of vertical blank lines, a frame rate, and a scanning scheme of the digital video signal that is reconfigured based on the received digital video signal.

The number of horizontal blank samples, the number of vertical blank lines, the frame rate, and the scanning scheme of the reconfigured digital video signal will be described with reference toFIG. 6.

In operation520, the processor230may reconfigure the digital video signal based on the number of horizontal blank samples and the number of vertical blank lines. For example, the processor230may reconfigure the digital video signal by adjusting the number of samples of the received digital video signal.

A method of reconfiguring the digital video signal will be described with reference toFIG. 7.

In operation530, the processor230may determine a system frequency of an analog video signal based on the number of horizontal blank samples, the number of vertical blank lines, and a frame rate.

The system frequency may be a frequency at which the analog video signal is generated. The system frequency may be a system clock.

For example, the system frequency may be determined by multiplying the number of samples in a single horizontal line, the number of vertical lines, and the frame rate.

For example, the system frequency may be determined based on Table 1. In Table 1, a numerical number may denote the number of samples of each item.

In operation540, the processor230may generate the analog video signal based on the system frequency.

For example, the processor230may generate the analog video signal by converting samples or data of the reconfigured digital video signal to the analog video signal based on the system frequency.

FIG. 6illustrates an example of a frame of a digital video according to example embodiments.

A frame600of a digital video may be a single image. The frame600of the digital video may include active data650that represents a scene and other data.

A preset height from an uppermost end of the frame600of the digital video may be a vertical blank line620. The vertical blank line620may be configured using a plurality of lines. The vertical blank line620may be used to distinguish a plurality of flames from one another.

A preset interval from a leftmost side of the frame600of the digital video may be a horizontal blank line640. The horizontal blank line640may be used to maintain the horizontal line630at a constant interval.

A resolution may relate to the number of pixels of the active data650. For example, the resolution may be a value acquired by multiplying the number of pixels included in the active data650among the horizontal lines630and the number of vertical lines included in the active data650among the vertical lines610.

Although at least one of the number of horizontal blank samples denoting the number of samples in the horizontal blank line640and the number of vertical blank lines620varies, the resolution may not vary. The sample may be data included in each horizontal line630.

According to an aspect, although the frame600of the digital video has a variety of resolutions, the processor230may reconfigure the frame600of the digital video frame by adaptively adjusting at least one of the number of samples in the horizontal blank line640and the number of vertical blank lines620.

FIG. 7is a flowchart illustrating a method of reconfiguring a digital video signal based on the number of horizontal blank samples and the number of vertical blank lines according to example embodiments.

According to an aspect, operation520ofFIG. 5may include operations710and720.

In operation710, the processor230may adjust the number of samples in each horizontal line of the digital video signal to include the determined number of horizontal blank samples.

The processor230may adjust the number of samples in the horizontal blank line640ofFIG. 6to be the determined number of horizontal blank samples. For example, the processor230may adjust the number of samples by removing a portion of the samples in the horizontal blank line640.

In operation720, the processor230may adjust the number of vertical lines of the digital video signal to include the determined number of vertical blank lines.

The processor230may adjust the number of blank lines610ofFIG. 6to be the determined number of vertical blank lines. For example, the processor230may adjust the number of lines by removing a portion of the vertical lines610.

In operation730, the processor230may reconfigure a Y-channel and a CbCr-channel of the digital video signal based on at least one of the number of horizontal blank samples and the number of vertical blank lines.

The Y-channel and the CbCr-channel may be included in each horizontal line of the digital video signal. For example, the Y-channel and the CbCr-channel may be an integrated channel. As another example, the Y-channel and the CbCr-channel may be separate channels each including data.

A method of reconfiguring the Y-channel and the CbCr-channel will be further described with reference toFIG. 8.

FIG. 8illustrates an example of reconfiguring a Y-channel and a CbCr-channel based on the number of horizontal blank samples according to example embodiments.

According to an aspect, each horizontal line of the digital video signal may include a Y-channel810and a CbCr-channel820. A ratio of luminance signal Y:Cb signal:Cr signal may be 4:2:2. Each of the Cb signal and the Cr signal may be a color difference signal.

Each of the Y-channel810and the CbCr-channel820may include an end of active video signal (EAV) code, horizontal blank data, a start of active video signal (SAV) code, and active data.

When the digital video signal are generated, the Y-channel810and the CbCr-channel820may be paired and generated in parallel.

The EAV code and the SAV code may include the same data or code.

According to an aspect, the number of horizontal blank samples, for example, the number of samples in each of vertical blank lines815and825may be an even number. For example, the number of samples in each of the vertical blank lines815and825may be 272 or more.

The processor230may reconfigure the Y-channel810and the CbCr-channel820by adjusting the number of horizontal blank samples, for example, the number of samples in the horizontal blank line815of the Y-channel and the number of horizontal blank samples, for example, the number of samples in the horizontal blank line825of the CbCr-channel. For example, the processor230may adjust the number of samples in the horizontal blank line815of the channel and the number of samples in the horizontal blank line825of the CbCr-channel so that each of the horizontal blank line815of the Y-channel and the horizontal blank line825of the CbCr-channel may have the determined number of horizontal blank samples. The determined number of horizontal blank samples may be an even number.

A method of adjusting the number of horizontal blank samples may be to determine a horizontal data timing.

FIG. 9illustrates an example of a digital video reconfigured based on a scanning scheme according to example embodiments.

A video scanning scheme may include a progressive scanning scheme and an interlaced scanning scheme.

In operation520ofFIG. 5, the processor230may reconfigure the digital video signal based on the scanning scheme of the digital video.

FIG. 9illustrates a digital video900reconfigured based on a progressive scanning scheme.

A vertical blank line may include a pulse line910and a blank line920.

The pulse line910may include a pre-equalizing pulse, a serration pulse, and a post-equalizing pulse. For example, each of the pr equalizing pulse, the serration pulse, and the post-equalizing pulse may include three lines. The pulse line910may include a total of 9 lines.

The blank line920may include 11 or more lines. The processor230may generate the reconfigured digital video900by adjusting the number of blank lines920.

Adjusting the number of blank lines920may be determining a vertical data timing.

According to an aspect, the processor230may display additional data on a preset area of a vertical blank line. A method of displaying additional data will be described with reference toFIG. 12.

FIG. 10illustrates another example of a digital video reconfigured based on a scanning scheme according to example embodiments.

FIG. 10illustrates a digital video1000reconfigured based on an interlaced scanning scheme.

Referring toFIG. 10, the digital video1000may include a first pulse line and a first blank line for first active data, and may include a second pulse line and a second blank line for second active data.

Each of the first pulse line and the second pulse line may include 9 lines.

Each of the first blank line and the second blank line may include 11 or more lines.

FIG. 11illustrates an example of a relationship between a digital video signal and an analog video signal according to example embodiments.

In operation340ofFIG. 3, the processor230may convert the reconfigured digital video signal to the analog video signal.

According to an aspect, the processor230may convert the digital video signal to the analog video signal based on a system frequency.

The processor230may convert the digital video signal to the analog video signal by converting each horizontal line of the digital video signal to the analog video signal.

Referring toFIG. 11, the processor230may generate a horizontal blank area1125of a horizontal line1120of an analog video signal corresponding to a horizontal blank area1115of a horizontal line1110of a digital video signal. For example, the number of samples of the horizontal blank area1125may be 20 or more.

According to a decrease in the number of samples in the horizontal blank area1115, a length of the horizontal blank area1125may be reduced.

The processor230may generate a horizontal sync, a front burst interval, a burst, and a back burst interval of the analog video signal to correspond to a video standard.

The number of samples in the horizontal sync may be 150 or more.

Each of the number of samples in the front burst interval and the number of samples in the back burst interval may be 20 or more.

The number of samples in the burst may be 70 or more.

A sync and burst area may be a section that includes the horizontal sync, the front burst interval, the burst, and the back burst interval.

Table 2 shows a timing about a horizontal line of an analog video. In Table 2, a numerical number may denote the number of samples of each item.

Here, p of the resolution denotes a progressive scanning scheme.

The processor230may generate an active area of the horizontal line1120of the analog video signal corresponding to video data or active data of the horizontal line1110of the digital video signal.

FIG. 12illustrates an example of additional data displayed on an analog video signal according to example embodiments.

In operation330ofFIG. 3, the processor230may display additional data on a preset area of a vertical blank line of a reconfigured digital video signal. The preset area of the vertical blank line may be a protocol transmission area.

The additional data may be a protocol. That is, the additional data may be data preset between a video transmission apparatus and a video reception apparatus.

When the processor230converts the reconfigured digital video signal to the analog video signal in operation340, the processor230may display a protocol on a protocol transmission area1200of the analog video signal converted using the displayed additional data. The displayed protocol may be a pulse indicating a bit string. For example, the displayed protocol may use a Manchester code scheme.

A start point and interval of the protocol may be based on a horizontal sync.

FIG. 13is a flowchart illustrating a method of converting a digital video signal to an analog video signal according to example embodiments.

In operation1310, the processor230may calculate a horizontal frequency of the analog video signal.

The horizontal frequency may be a burst frequency.

The horizontal frequency may be calculated according to Equation 1.
Horizontal frequency=1(frame rate*number of vertical lines)  [Equation 1]

In operation1320, the processor230may calculate a subcarrier frequency based on the horizontal frequency.

The subcarrier frequency may be calculated according to Equation 2.
Subcarrier frequency=(2N+1)/2*horizontal frequency.  [Equation 2]

In Equation 2, N denotes a natural number.

(2N+1)/2 folds of the horizontal frequency may be used to avoid interference between a color difference frequency and a luminance frequency of the analog video signal.

Table 3 shows an example of the calculated subcarrier frequency.

In operation1330, the processor230may convert the digital video signal to analog video signal based on the horizontal frequency and the subcarrier frequency.

When converting the digital video signal to the analog video signal, the processor230may convert the digital video signal to the analog video signal using a frequency corresponding to two times or more of the system frequency to achieve a stable operation.

When converting the digital video signal to the analog video signal, the processor230may convert the digital video signal to the analog video signal using a frequency corresponding to four times or more of the subcarrier frequency to achieve a stable operation.

According to an aspect, the processor230may modulate a color difference signal of the analog video signal based on the subcarrier frequency. The modulated analog video signal will be described with reference toFIG. 14.

FIG. 14illustrates an example of an analog video signal in which a color difference signal is modulated according to example embodiments.

Referring toFIG. 14, an analog video signal1410modulated at the processor230may include a luminance frequency signal1420and a modulated color difference frequency signal1430.

The luminance frequency signal1420may have a first frequency bandwidth in which a first frequency is maximum.

According to an aspect, a highest frequency in a bandwidth of the color difference frequency signal1430may be lower than the first frequency. That is, the bandwidth of the color difference frequency signal1430may be included in the first frequency bandwidth.

When the bandwidth of the color difference frequency signal1430is included in the first frequency bandwidth, and when a subcarrier frequency is high, an alternating color issue and a luminance inclusion issue may decrease compared to a standard scheme.

The units and/or modules described herein may be implemented using hardware components, software components, and/or combination of the hardware components and the software components. For example, the apparatuses and the hardware components described herein may be implemented using, for example, a processor, a controller and an arithmetic logic unit (ALU), a digital signal processor, a microcomputer a field programmable array (FPA), a programmable logic unit (PLU), a microprocessor, or one or more general-purpose computers or specific-purpose computers such as any other device capable of responding to and executing instructions in a defined manner. The processing device may run an operating system (OS) and one or more software applications that run on the OS. The processing device also may access, store, manipulate, process, and create data in response to execution of the software. For purpose of simplicity, the description of a processing device is used as singular, however, one skilled in the art will be appreciated that a processing device may include multiple processing elements and/or multiple types of processing elements. For example, a processing device may include multiple processors or a processor and a controller. In addition, different processing configurations are possible, such a parallel processors.