KR100608810B1 - A method and a apparatus of improvement image quality at multimedia communication for mobile phone - Google Patents

Abstract

According to an aspect of the present invention, there is provided a camera unit for distinguishing a face region, a human region, and an outline region in a mobile terminal image communication, and setting respective quantization steps to transmit images with optimum image quality. A control unit for detecting and controlling a face region, an outline region, and a human region of an image signal input from the camera unit to apply different quantization steps; A template unit for detecting a face position portion of an image signal by a template, determining a size of a face region by color signal analysis, and determining a human region and an outline region; A compression unit for compressing and outputting different quantization steps to respective areas of the image signal output from the template unit; And a modulation and demodulation section for outputting the image signal compressed from the compression section by the corresponding encryption and modulation processing.

Description

Device and method for improving video communication image quality of mobile terminal {A METHOD AND A APPARATUS OF IMPROVEMENT IMAGE QUALITY AT MULTIMEDIA COMMUNICATION FOR MOBILE PHONE}

1 is a state diagram of a video communication image of a mobile terminal according to one embodiment;

2 is a flowchart of a video communication transmission method according to the prior art;

3 is a functional configuration diagram of a video communication image quality improving device of a mobile terminal of the present invention;

4 is a flowchart of a method for improving image communication quality of a mobile terminal according to the present invention;

5 is an explanatory diagram of a video communication image quality improving system of the present invention portable terminal.

          ** Explanation of symbols on the main parts of the drawing **

100: wireless unit 110: control unit 120: modulation and demodulation unit

130 memory unit 140 input / output unit 150 compression unit

160: template portion 170: camera portion

The present invention improves the image quality of video communication using a mobile terminal, and in particular, sets a template that distinguishes a face, a human region, and an outline of an image signal, sets different quantization steps, and compresses each channel to allow data transmission rate. The present invention relates to an apparatus and method for improving image communication quality of a portable terminal for transmitting an optimal quality.

Common means of communication with the other party include the use of sound (AUDIO or SOUND), the inclusion of an image (IMAGE), the transmission of signs and characters, the communication of the senses, and the like. It was the most common to use sound.

As a representative means of telecommunication, there is a mobile terminal for mobile communication, and the mobile terminal for mobile communication (MS) is a service area formed by a corresponding base station (RAN: RADIO ACCESS NETWORK) of a registered mobile communication system (SERVICE AREA). By freely moving inside, the mobile switching center (MSC: MOBILE SWITCHING CENTER) monitors, controls, and switches the communication path established by SWITCHING. It is a high-tech wireless communication device that moves everywhere.

The mobile terminal (MS) initially communicated mainly on a voice-grade signal medium, and in the next generation, it has developed into a communication method for rapidly transmitting a large amount of information such as a message or an email using a text-grade data signal medium. In the 3rd generation, the multimedia system including the image media in the voice media and the text media has been developed into a communication method for quickly transmitting more information to the other party.

The third generation multimedia communication method portable terminal as described above uses a video and audio signal to communicate with a wirelessly connected counterpart. .

However, since the multimedia level video signal has a larger amount of data to transmit than the voice level or text level signal, it requires a wide bandwidth (BANDWIDTH) and a high speed data transmission technology. Since the area or bandwidth is limited and multiple subscribers must communicate at the same time, there are many technical restrictions such as fixed allocation or restriction without increasing the data transmission rate per channel.

That is, in the wireless channel serviced by the mobile communication system, the amount of data that can be transmitted is limited, and the transmitted image signal has an opposite condition of increasing the amount of data to be transmitted in order to maintain good image quality.

RATE CONTROL and compression techniques are used to transmit the maximum amount of data and maintain optimal image quality without distortion by making the most of the amount of data that can be transmitted by the wireless channel of the mobile communication system.

The RATE CONTROL technology distributes and controls data of a video signal to be transmitted, and distributes the data optimally in accordance with a data size or a target bit amount that an allocated channel can transmit, thereby maintaining and transmitting optimal image quality without distortion. The compression technique is to convert the data to be transmitted into a small capacity according to a predetermined rule. Generally, the compression technique and the rate control technique are used together, and the present invention relates to the compression technique field.

In general, video communication using a mobile terminal communicates with each other while looking at each other's faces, and has a feature of less change or movement of an image than a general natural video.

As described above, various signal processing, transmission methods, and compression methods are applied to transmit an image communication signal using a limited data rate of a channel and having a large amount of data.

The video communication that communicates while looking at the face of the other party has a small change in screen or a screen difference, and in particular, the background screen has a small change and the time is not concentrated, and the time is concentrated on the other side's face and outline. have.

The signal processing method using the shape information characteristics of the video communication and changing the corresponding compression rate is an efficient method of providing an optimum picture quality to the other party in a limited data rate environment of the channel, so it is possible to develop a more efficient image compression technology. There is a need.

Hereinafter, a video communication method of a mobile terminal according to the prior art will be described with reference to the accompanying drawings.

Attached to explain the prior art, FIG. 1 is a state diagram of a video communication image of a mobile terminal according to an example, and FIG. 2 is a flowchart of a video communication transmission scheme according to the prior art.

Referring to FIG. 1, an example of an image or an image to be transmitted is illustrated when performing image communication with a portable terminal.

As shown in FIG. 1, in the case of video communication using a portable terminal, the center portion where the eyes are concentrated is the face portion, the next order is the contour region of the person, and the gaze decreases on the background screen.

That is, since the area where the eyes are concentrated is the face area, and the next is the contour area, the quality of the face area is the most important.

Hereinafter, with reference to the accompanying Figure 2, a description will be given of a video communication method of a mobile terminal according to the prior art.

An image signal is input through a camera unit integrally provided in the portable terminal MS (S10), and the signal is processed by the input image signal and analyzed as a frequency component (ANALYZE).

The high frequency component of the image signal analyzed as the frequency component is removed and compressed as described above (S20), and modulated by the corresponding encryption, and the encrypted and modulated video signal as described above is wirelessly transmitted to the designated counterpart (S30).

When the image signal is analyzed by the frequency component, in general, the contour portion that separates the object is analyzed by the high frequency signal component, and the other portion is analyzed by the low frequency signal component.

The digital conversion of the high frequency signal increases the size of the data, and also requires a lot of time and data transmission speed in order to transmit the data.

Therefore, low frequency components that can transmit many image signals with the same amount of data are mainly transmitted, and some of the high frequency components are removed. Therefore, compression transmission is performed while maintaining optimum image quality in accordance with a limited data transmission rate.

However, in the conventional compression technique as described above, when a large number of high frequency portions are deleted, a blocking phenomenon occurs in the contour portion, thereby degrading image quality.

In addition, another conventional technique is to transmit image signals by applying different compression ratios in units of frames or divided frames, but there is a problem in that they are not applicable to video calls.

The present invention divides image signals into spatial templates and applies different compression ratios to each other. The size of the face portion detected by the template is determined, the contour area and the human area are respectively determined, and sequential compression rates are applied. It is an object of the present invention to provide an apparatus and method for improving image communication quality of a portable terminal which communicates with an image signal having an optimum image quality in a limited data rate environment.

The present invention has been made to achieve the above object, the camera unit for photographing and inputting the image signal for the image communication for the control signal; A control unit for detecting and controlling a face region, an outline region, and a human region of an image signal input from the camera unit to apply different quantization steps; A template unit connected to the control unit, detecting a face position portion of an image signal by a template, determining a size of a face region by color signal analysis, and determining a human region and an outline region; A compression unit which is connected to the control unit and compresses and outputs a different quantization step to each area of the image signal output from the template unit; And a modulation / demodulation unit connected to the control unit and configured to output the image signal compressed from the compression unit by corresponding encryption and modulation.

In addition, the present invention has been made in order to achieve the above object, the preparation process for setting and inputting the basic template of the face region, the human region and the contour region of the image frame to the mobile terminal; A face process of detecting a flesh color pixel and determining a size of a face area in comparison with a face template when an image signal is input to the portable terminal; A size process of determining the size of the human area and the contour area in proportion to the size of the face area of the image signal; A quantization step value is sequentially set in the order of the face region, the contour region, the human region, and the background region, and is compressed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, an apparatus and method for improving image communication quality of a portable terminal will be described with reference to the accompanying drawings.

3 is a functional configuration diagram of a video communication image quality improving apparatus of a mobile terminal according to the present invention, and FIG. 4 is a flowchart illustrating a method of improving video communication image quality of a mobile terminal according to the present invention. Is a diagram illustrating a video communication image quality improving method of a mobile terminal according to the present invention.

According to the present invention with reference to FIG. 3, a description will be given of an apparatus for improving image communication quality of a mobile terminal. The wireless unit is connected to the control unit 110 and wirelessly transmits and receives an image signal compressed and encrypted and modulated by a corresponding control. With 100,

It detects the face area of the image signal input from the camera unit 170, determines the size, detects the contour area and the human area, controls and monitors to apply different quantization steps, and receives a corresponding control command from the input / output unit. And inputting an image signal by controlling the camera unit, applying the input image signal to the template unit, and controlling the template unit to output the image signal into a face region, an outline region, a human region and a background region, and output the image signal. Applying to the compression unit, and controlling the compression unit to output a compressed image signal by sequentially applying a quantization step in the order of the face region, the contour region, the human region, and the background region, and applying the compressed image signal to the modulation / demodulation unit, The control unit 110 for wireless transmission since the modulation and demodulation unit is controlled and applied to the wireless unit through encryption and modulation processing

A modulation and demodulation unit 120 connected to the control unit 110 and outputting the image signal compressed from the compression unit 150 by corresponding encryption and modulation processing;

A memory unit 130 connected to the controller 110 for recording, storing and outputting an operating program and data of the portable terminal;

An input / output unit 140 connected to the control unit 110 and inputting / outputting a multimedia signal and inputting a control command and a dialing signal including compression transmission;

The controller 110 is connected to the control unit 110 and compressed and outputs by applying different quantization steps to respective regions of the image signal output from the template unit 160. The control unit 110 controls the control unit 110. A compression unit 150 that analyzes the image signal and compresses and outputs the quantization step sequentially in the order of the face region, the contour region, the human region, and the background region;

It is connected to the control unit 110 and detects the face position part of the image signal by the spatial template, and determines the face size by the color signal analysis and determines the human area and the contour area. Outputs a face position, detects a skin region pixel based on the face position, determines the size of the face region, sets a region proportionally proportional to the determined face size, and determines the human region. A template unit 160 for setting an area proportionally proportional to the face size to determine the contour area, and outputting an image signal divided into the areas determined as described above;

The camera unit 170 which captures and inputs an image signal for image communication in a frame unit according to the control signal applied from the controller 110 is included.

Hereinafter, according to the present invention having the above-described configuration, it will be described in detail with reference to the accompanying drawings, an image communication image quality improving device of a mobile terminal (MS).

When the operating power is applied, the controller 110 of the portable terminal MS receives and sets an operation program and data from the memory unit 130, and thus, the controller 110 is in a standby state for providing a mobile communication service.

The controller 110 recognizes a corresponding control signal input from the input / output unit 140, and is for image communication. The controller 110 controls the camera unit 170 to receive an image signal in a frame unit, and inputs the image signal. Is applied to the template unit 160.

The template unit 160 stores a template having a basic size of a face area, a human area, and a contour area, and analyzes pixels corresponding to the basic size face area template from the input image communication image signal.

The pixel PIXEL of the skin color is detected in the analysis, and if the skin color pixel is detected in the analysis, the pixel area is determined as a face area, and all the areas where the skin color pixel is detected are detected to estimate and set the size of the face area.

When the face area to be transmitted to the counterpart is set for video communication as described above, the human area and the contour area which are proportionally proportional to the template based on the size of the face area are estimated and set based on the template size.

That is, the face region, the human region, the contour region and the background region of the image signal inputted by the template unit 160 are output.

Referring to FIG. 5, the face region 1 is distinguished from the image signal input by the template unit 160, the human region 2 is distinguished in the following order, and the outline region 3 is next. The states for distinguishing are shown in order.

The controller 110 applies the image signal divided into the respective regions from the template unit 160 to the compression unit 150.

The compression unit 150 analyzes the input image signal and sets a small quantization step value so that the highest or most bit amount is allocated to the face area, and sets a small quantization step value in the following order in the contour area where the human outline can be confirmed. In this case, the person area which can confirm the whole figure of the person is set to the next quantization step, and the background area is set to the largest quantization step value so that the smallest bit amount is allocated.

If the quantization step value is set to be small, the image quality is improved by allocating many bits to the corresponding area, and if the quantization step value is large, the bit rate is assigned to the corresponding area to increase the compression ratio.

The image signals compressed at different compression rates by the compression unit 150 as described above are applied to the modulation / demodulation unit 120 under the control of the control unit 110, and encrypted by the modulation / demodulation unit 120 in a corresponding manner. It is modulated with and is applied to the radio unit 100 and is wirelessly transmitted to the called party.

According to the present invention having the above-described configuration, in the data transmission size environment that is allowed by the channel allocated for video communication in the mobile communication system, the image quality of the face area where attention is concentrated is best, and the contour area, the human area, and the background area are the best. In order to improve the picture quality.

Therefore, there is an advantage in that the image quality is optimally improved and transmitted in the allowed range of mobile communication radio channel resources.

Hereinafter, a method of improving image communication quality of a mobile terminal according to the present invention will be described with reference to the accompanying drawings.

A preparation process (S100) for setting and inputting a basic template of a face region, a human region and an outline region of an image frame to a mobile terminal (MS);

When the image signal is input to the portable terminal MS in the preparation process S100, the flesh color pixel PIXEL is detected and the size of the face area is determined in comparison with the face template TEMPLET. Determining whether an image signal for image communication is input to the input signal (S110); When the image signal is input in the step (S110), the face process comprising the step of detecting the boundary area of the flesh pixel (PIXEL) and determining the size of the face area in contrast to the template of the face area (S120),

Determining the size of the human area and the contour area in proportion to the size of the face area of the image signal by the face process, and determining and setting the size of the human area in proportion to the size of the face area determined in the face process (S130). ; A size process consisting of determining and setting the size of the contour area in proportion to the size of the face area determined in the face process (S140);

The quantization step values are sequentially set in the order of the face region, the contour region, the human region, and the background region of the image signal of the size process, and are transmitted by compressing, encrypting, and modulating the image signal. Sequentially setting quantization step values in order of a face region, an outline region, a human region, and a background region (S150); Compression process consists of a process of compressing, encrypting, modulating and transmitting according to the quantization step value set in the process (S150) (S160).

Hereinafter, the above-described configuration will be described in detail with reference to the accompanying drawings, a method for improving image communication quality of a mobile terminal according to the present invention.

The multimedia mobile terminal (MS) is capable of video communication, and the template unit 160 stores the template of the face area, the human area and the contour area to a predetermined size in advance (S100).

The controller 110 of the mobile terminal MS determines whether an image signal is input, and when the image signal is input, analyzes the surrounding pixels PIXEL based on the template TEMPLET of the face region 1. A pixel having flesh color is detected, and when the flesh color pixel is detected, all the flesh color pixel areas around the template are checked to determine and set the size of the face area (S120).

The size of the human area 2 by the template of the human area 2 is determined and set based on the face area 1 set in the step S120 (S130).

That is, the size of the human area 2 is determined and set from the template of the human area 2 based on the size ratio of the template of the face area set previously and the face area 1 set by the color pixel detection.

In the same manner as described above, the size of the contour area 3 proportional to the size of the face area 1 is determined and set (S140).

As described above, the quantization step values are sequentially set in the face area 1, the contour area 3, the human area 2, and the background area determined from the image signal (S150). The area is compressed, and is encrypted and modulated and applied to the wireless unit 100 so as to be transmitted to the counterpart having video communication (S160).

Since the highest quantization step is set in the face region 1 and many bits are allocated, the image quality is compressed to the best state, and the lowest quantization step is set in the background region and the least bit is allocated, thereby compressing at the highest compression rate. The total number of bits transmitted through the compression is not exceeded the bit number range allowed by the channel.

Therefore, the present invention having the above-described configuration has an advantage of improving the transmission of the face area where the focus is focused to the optimum image quality in the data rate range allowed by the channel allocated by the mobile communication system for video communication.

The present invention having the above-described configuration compresses and transmits the face region at the highest image quality and transmits the background region at the highest compression rate among the video communication frame unit signals, and thus is optimal in the data rate range allowed by the wireless channel of the mobile terminal. There is an industrial use effect of transmitting image quality.

In addition, in image communication using a mobile terminal, since the image quality of the face area where the gaze is concentrated is most improved and transmitted, there is an effect of convenience in use such that the image quality is improved in the entire image signal frame unit.

Claims (10)

A camera unit which photographs and inputs an image signal for image communication by a control signal; A control unit which detects a face region, an outline region and a human region of the image signal input from the camera unit, controls and monitors a different quantization step to be applied; A template part connected to the control part and detecting a face position part of an image signal by a template, determining a size of a face area by color signal analysis, and determining a human area and an outline area; A compression unit which is connected to the control unit and compresses and outputs a different quantization step to each area of the image signal output from the template unit; And a modulation and demodulation unit for connecting to the control unit and for outputting the encrypted and modulated image signals compressed from the compression unit. According to claim 1, A wireless unit for wirelessly transmitting and receiving an image signal compressed and encrypted and modulated by the control unit; A memory unit for accessing the control unit to record, store and output an operation program and data of the portable terminal; And an input / output unit for connecting to the control unit, inputting / outputting a multimedia signal, and inputting a control command including a compression transmission and a dialing signal. The method of claim 1, wherein the template portion, The normal face position is detected by the template of the image signal input from the camera unit, Detecting the flesh color pixel area of the face position to determine the size of the face area, Determining a human area by setting a region proportionally proportional to the determined face size, Determining the contour area by setting a region proportionally proportional to the determined face size, And an image signal divided into the areas determined as described above. The method of claim 1, wherein the compression unit, Analyzing the image signal applied from the template unit under the control of the controller, and compresses and outputs the quantization step sequentially in the order of face region, contour region, human region and background region. Video communication image quality improvement device. The method of claim 4, wherein And the quantization step value of the face area is set to be the smallest, and the quantization step value of the background area is to be set to the largest. The method of claim 1, wherein the control unit, Receiving a corresponding control command from the input / output unit, controlling the camera unit to input an image signal, The input image signal is applied to a template unit, and the template unit is controlled to divide the image signal into a face region, an outline region, a human region, and a background region. The divided image signal is applied to a compression unit, and the compression unit is controlled to sequentially compress and apply a quantization step value in order of a face region, an outline region, a human region, and a background region. And applying the compressed image signal to a modulation / demodulation unit, and controlling the modulation / demodulation unit to perform encryption and modulation processing to apply to a wireless unit, thereby wirelessly transmitting the image communication image quality improvement device of the portable terminal. Preparing and inputting a basic template of a face region, a human region and an outline region of an image frame on a mobile terminal; A face process of detecting a flesh color pixel and determining a size of a face area in comparison with a face template when an image signal is input to the portable terminal; A size process of determining the size of the human area and the contour area in proportion to the size of the face area of the image signal; And a compression process of sequentially setting the quantization step values in the order of the face region, the contour region, the human region, and the background region, and compressing, encrypting, and modulating and transmitting the quantization step values. The method of claim 7, wherein the facial process, Determining whether an image signal for image communication is input to the portable terminal; And detecting the flesh color pixel when the image signal is input, and determining and setting a size of the face area in comparison with a template of the face area. The method of claim 7, wherein the size process, Determining and setting the size of the human area in proportion to the size of the face area determined in the face process; And determining and setting a size of the contour area in proportion to the size of the face area determined in the face process. The method of claim 7, wherein the compression process, Sequentially setting the quantization step values in the order of the face region, the contour region, the human region, and the background region of the image signal determined and set in the size process; And compressing, encrypting, modulating, and transmitting the image according to the set quantization step value.

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