JP2009081753A - Wireless communication system, transmitter and receiver - Google Patents

Abstract

The present invention relates to a wireless communication system, and provides a technique capable of suppressing or improving a quality deterioration of a display image or the like on a receiving side according to a wireless communication environment.
In this wireless communication system, a transmitter 100 detects the degree of congestion (empty time ratio) of a wireless transmission path, and determines the coding rate of video data to be transmitted to a receiver 110 according to the detection result. change. Correspondingly, the receiver 110 switches and controls whether to perform image quality improvement processing (super-resolution processing or the like) on the received video data. For example, data that has been changed to a low rate on the transmission side and transmitted at the time of congestion is displayed after image quality improvement processing on the reception side.
[Selection] Figure 1

Description

  The present invention relates to a system (wireless communication system) for wirelessly transmitting data (signals) such as video and audio, and more particularly to video rate control and image processing.

  Short-range wireless communication systems such as wireless LANs are rapidly spreading from offices to homes in conjunction with the spread of Internet connections. In recent years, its use is not limited to file transfer between computers, but there is an increasing demand for connecting AV equipment to distribute video and audio.

  On the other hand, it is known that the transmission quality at the time of wireless transmission is greatly influenced by the communication environment (transmission path environment and surrounding environment) as compared with the wired communication. In general, video and audio that require high transmission quality may be difficult to wirelessly transmit with desired quality due to environmental influences. For example, when using CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance), which is an access method used in wireless LAN, etc., if the same type of equipment operates in the vicinity using the same frequency, it acts as interference. . As a result, the throughput of wireless transmission is greatly reduced, and the quality of video and audio after wireless transmission is seriously hindered. That is, due to radio transmission quality (interference, congestion, etc. in the radio transmission path), a failure such as disturbance or stop in the received video occurs, and the quality is greatly reduced.

  The following technique (video rate control technique, referred to as the first technique) is known as one method for suppressing such quality degradation as image disturbance. In this technique, the amount of data actually transmitted in the communication environment is adjusted by changing the rate (compression rate, etc.) of video or the like to be transmitted (transmitted) in accordance with the changing communication environment. This suppresses quality degradation on the receiving side. In this technology, particularly when the communication environment (wireless transmission path condition) is poor (according to the deterioration of the communication environment), the compression rate of video data (stream data) to be transmitted is increased (encoded) by video rate control. Transmit at a lower rate. As a result, the amount of data transmitted through the wireless transmission path is reduced. On the other hand, when the communication environment is good, the video data is transmitted with a low compression rate (high encoding rate).

  The above-described techniques are described in, for example, Japanese Patent Application Laid-Open No. 2002-204278 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2004-153610 (Patent Document 2).

  However, with the above-described technology, the video data with a reduced rate naturally reduces the quality (image quality) when the video is displayed on the receiving side (receiver), which lowers viewer satisfaction. I cannot deny it.

On the other hand, a super-resolution processing technique (referred to as a second technique) is known as a technique for obtaining a high-quality image from a low-quality image. This technique is obtained by synthesizing a single high-resolution image from a plurality of low-resolution images that are close in terms of time or space. This technique is described in, for example, Japanese Patent Laid-Open No. 8-336046 (Patent Document 3). Also, as an application of this technology, there is a known method for realizing higher quality of moving images by obtaining higher quality frame data using a plurality of frames (images) in moving image (video) data. It has been.
JP 2002-204278 A JP 2004-153610 A JP-A-8-336046

  In the prior art, when a video or the like (video data or the like) is transmitted (transmitted) wirelessly, a desired transmission rate may not be obtained due to the surrounding environment (deterioration of transmission path conditions). Disruption, stoppage, etc., image quality degradation, etc. occur. In order to prevent this, when the transmission rate (encoding rate) of the video or the like is set low, the quality of the received video or the like is lowered, and the satisfaction of the viewer is lowered.

  In other words, in the first technique, the transmission side (transmitter) controls the rate of the video to be transmitted (transmitted) according to the surrounding environment (low coding rate) so that the received video does not fail. In the case of a change to (or the like), the quality of the video or the like to be displayed (reproduced) is deteriorated on the receiving side (receiver).

  The present invention has been made in view of the problems as described above, and its main purpose is related to a wireless communication system, and the quality of a display image or the like on the receiving side according to a wireless communication environment (wireless transmission path condition). The object is to provide a technique capable of suppressing or improving the decrease.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows. In order to achieve the above object, a representative embodiment is a wireless communication system that wirelessly transmits (transmits / receives) video data (signals) between a transmitter (transmission side) and a receiver (reception side). This technique is characterized by having the following configuration.

  In this wireless communication system, processing control for changing the rate (image quality) of target data (particularly video data) to be transmitted (transmitted) from the transmission side to the reception side in accordance with the wireless communication environment (ambient environment) (the first control). The first processing control corresponding to the technology (video rate control technology) is performed by, for example, the transmission side. Corresponding to the first processing control, the receiving side performs processing for improving (recovering) image quality in the display (reproduction) of the data, for the received target data, according to the rate. Processing control to be performed (second processing control corresponding to the second technology (super-resolution processing technology)) is performed. As a result, the transmission efficiency in the wireless communication environment (adjustment of the amount of transmission data) and the deterioration of quality (image quality) such as video display on the receiving side are suppressed or improved.

  In this wireless communication system, for example, the transmitting side (transmitter) detects or measures the status (interference, congestion, etc.) of the wireless transmission path (the radio frequency used by itself and other peripheral devices). And means for changing the transmission rate (encoding rate, compression rate, etc.) of the target data (video data, etc.) according to the detection result.

  Corresponding to the configuration on the transmission side, the reception side (receiver) is provided with means for performing image quality improvement processing (super-resolution processing, etc.) on the received target data, and whether to perform the processing (ON / OFF). Off) and the like.

  In the means for changing the rate, for example, switching (selection) of the video source or the encoded video data or the change of the encoding rate of the encoding process is performed.

  The image quality improvement processing means performs, for example, super-resolution processing (frame-unit resolution conversion processing), frame rate conversion processing, etc., on an image (frame) group constituting the received video data. In the super-resolution processing, processing for obtaining one high-resolution image from a plurality of low-resolution images is performed.

  The processing operation (for example, transmission of video data from the transmitter to the receiver) and control in this system are as follows, for example. In the transmitter, as the first processing control, the degree of congestion is detected as the state of the wireless transmission path (the radio frequency channel (radio wave) to be used) between the transmitter and the receiver, and the degree of congestion is low (that is, the state is good). In such a case, the target data is transmitted at a relatively high transmission rate (for example, at the original high rate). In that case, the receiver turns off image quality improvement processing (super-resolution processing or the like) for the reception target data as the second processing control. In the transmitter, as the first process control, when the degree of congestion is high (that is, the situation is bad), the transmission rate of the target data is relatively lowered (for example, from the original high rate to the low level). Change to rate) and send. In that case, in the receiver, as the second processing control, the image quality improvement processing (super-resolution processing or the like) for the reception target data is turned on to improve the display image quality (at least the transmission rate (reception video data Display rate (image quality) higher than (rate).

  As described above, transmission efficiency (adjustment of transmission data amount) at the time of wireless transmission is realized by changing the transmission rate of the target data in accordance with the communication environment (its change) in the first processing control. After the reception on the side, the display image at the original high rate or the rate after the image quality improvement is obtained by improving the image quality by the second processing control.

  This system is, for example, a wireless communication system that wirelessly transmits data such as video between a transmitter and a receiver, and the transmitter is a wireless transmission path between the transmitter and the receiver. In response, the encoding rate of the first video data to be transmitted to the receiver is changed, and the receiver performs frame unit according to the rate of the first video data received from the transmitter. In the transmitter, when the state of the wireless transmission path is not good, the transmitter encodes the code of the first video data. The transmission rate is changed to a lower value, and the image quality improvement processing including the super-resolution processing is turned on in response to the transmission.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows. According to a typical embodiment, it is related to a wireless communication system, and it is possible to suppress or improve a deterioration in quality of a display image or the like on the receiving side according to a wireless communication environment (wireless transmission path condition).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

(Embodiment 1)
A radio communication system according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a functional block configuration in the wireless communication system of the first embodiment. In the first embodiment, a wireless communication system employing CSMA / CA used in a wireless LAN is used for access control. The system includes a transmitter 100 and a receiver 110 that perform wireless communication. The transmitter 100 includes a coding rate changing unit 101, a baseband unit 102, a wireless transmission unit 103, an antenna (transmission antenna) 104, an antenna (reception antenna) 105, a wireless reception unit 106, and a control unit 107. The receiver 110 includes an antenna 111, a wireless reception unit 112, a baseband unit 113, a video decoding unit 114, a super-resolution processing unit 115, switches 116 and 117 (image quality improvement unit 118), and the like. For example, a display unit (display) 120 is connected to the receiver 110.

  The overall flow of processing and the like in this system will be described with reference to FIG. This processing includes transmission (transmission) of video data and the like through a wireless transmission path (radio frequency channel) from the transmitter 100 to the receiver 110, and display (reproduction) of the received video data and the like at the receiver 110, Etc.

  A video source 108 is input to the transmitter 100. The video source 108 is not particularly limited. In response to an instruction (control) from the control unit 107, the encoding rate changing unit 101 converts the resolution of each frame (image) constituting the video (changes the encoding rate) to the video source 108. Process). Thereby, the amount of video data to be transmitted through the wireless transmission path is adjusted. A video rate instruction signal (A3) is input from the control unit 107 to the coding rate changing unit 101. Instructions for the control unit 107 will be described later.

  The transmitter 100 wirelessly transmits the video data 109 (transmitted radio signal: packet or other radio wave) from the antenna 104 through the processing in the baseband unit 102 and the wireless transmission unit 103 after the encoding rate changing unit 101. Send. The wireless transmission unit 103 notifies the control unit 107 of timing (starting transmission time) at which wireless transmission of the video data 109 (packet or the like) from the transmitter 100 starts and ends. From wireless transmission section 103 to control section 107, a signal (A1) of its own transmission timing is input.

  On the other hand, another antenna 105 of the transmitter 100 receives radio waves related to a wireless transmission path (radio frequency channel) between the transmitter 100 and the receiver 110. The antenna 105 receives a packet using a radio frequency included in a radio frequency channel used by the transmitter 100 in a device (wireless communication device) existing in the vicinity of the transmitter 100 and other radio waves. Then, the reception start and end timing (other device transmission timing) is notified from the antenna 105 to the control unit 107 through the wireless reception unit 106 as a signal (A2) of the other device transmission timing. In other words, the transmitter 100 obtains information on the transmission timing of the other device by performing carrier sense based on CSMA / CA (detection of radio waves in the radio frequency channel used by the transmitter 100).

  In the first embodiment, the transmitter 100 includes the transmission / reception antennas 104 and 105. However, the present invention is not limited to this, and a configuration may be employed in which a transmission / reception antenna is provided.

  As described above, the control unit 107 collects information on radio waves related to the surrounding environment of the transmitter 100. This information is information on transmission start and end timings for all devices that are located in a range that can be received by the transmitter 100 and that communicate using radio waves of the same radio frequency as the radio frequency channel used by the transmitter 100. is there. Accordingly, the control unit 107 calculates the time used by the transmitter 100 (own device) for transmission (own device transmission time) and the time used by other devices for transmission (other device transmission time) on the time axis. it can. This information (time) is an index (congestion degree) of the radio frequency congestion used by the transmitter 100 for transmission of the target data. That is, the control unit 107 can detect and grasp the state of interference and congestion (vacancy) in the wireless transmission path (radio frequency) to be used as the degree of congestion (vacancy time rate).

  Based on the above information, the control unit 107 can instruct the coding rate changing unit 101 as a signal (A3) with the coding rate (transmission rate) corresponding to the degree of congestion. For example, the control unit 107 instructs a low coding rate when the degree of congestion is large (when the idle time rate is small), and when the degree of congestion is small (when the idle time rate is large), the control unit 107 sets a high coding rate. Instruct.

  As described above, in the transmitter 100, the transmission rate of the video data 109 to the receiver 110 is low when the transmission opportunity by CSMA / CA is not sufficient due to radio interference from peripheral devices (when the degree of congestion is high). If the transmission rate is changed to the coding rate, and it is not (when the degree of congestion is low), it can be transmitted at the high coding rate. As a result, the video data 109 can be delivered to the receiver 110 while suppressing packet loss and discard of the video data 109 in wireless transmission.

  The processing control in the transmitter 100 will be described in more detail with reference to FIG. FIG. 2 shows a processing flow of wireless channel condition detection and coding rate instruction (function switching operation) in the control unit 107 of the transmitter 100 (note that S represents a processing step).

  Control and instruction from the control unit 107 to the coding rate changing unit 101 can be realized as follows, for example. The control unit 107 calculates the ratio of time during which wireless transmission is not performed (free time ratio) for all devices including the transmitter 100 (own device) in a certain observation time in the surrounding environment, and calculates this value. Compared with a predetermined threshold value, if it is larger than this threshold value, a high coding rate is instructed. Conversely, if it is small, a low coding rate is instructed. This will be described in detail as follows.

  In S201, the control unit 107 performs the following free time rate calculation process (congestion degree calculation process). As described above, the control unit 107 includes the status of the wireless transmission path, that is, the time during which the transmitter 100 (own device) performs wireless transmission, and the peripheral device (other device) that uses the same frequency as the own device. Information on the time when is performing wireless transmission is collected. Here, on the time axis, a time t1 (t1 = −Tm) retroactive by an observation time Tm having a predetermined size from the current time t0 (t0 = 0) is set as a starting point, and the current time t0 is set as an end point. Within the length of time, the time excluding the time when the transmitter 100 (own device) was wirelessly transmitting (own device transmission time Tx) and the time when the other device was wirelessly transmitting (other device transmission time Ty) It is possible to calculate the ratio of (Tm−Tx−Ty), that is, the time during which no peripheral devices including the own device wirelessly transmit in Tm. Here, this ratio is called a free time ratio (α). As a calculation formula, α = (Tm−Tx−Ty) ÷ Tm. This free time rate (α) can be used as a measure corresponding to an index (congestion degree) indicating the degree of congestion on the time axis for the radio frequency used by the transmitter 100 (free time rate (α)). A larger value corresponds to a lower degree of congestion).

  In S202, the calculated idle time rate (α) is compared with a predetermined threshold value. If α is larger than the threshold value (S202-Y), the transmitter 100 considers that there is sufficient opportunity to transmit, and in S203, the control unit 107 sends a signal (A3) to the coding rate changing unit 101. ) To indicate a high encoding rate (in other words, a high resolution setting is notified). Specifically, for example, the control unit 107 transmits (function off) a predetermined value (function off) with the number of pixels (resolution) of each frame of the video data as it is (the rate (resolution) of the video source 108). For example, 0) is designated.

  On the other hand, when the idle time rate (α) is equal to or smaller than the threshold (S202-N), the control unit 107 considers that there is not enough opportunity for the transmitter 100 to transmit, and the control unit 107 encodes the coding rate changing unit 101. In contrast, a low encoding rate is instructed (in other words, a low resolution setting is notified). Specifically, for example, the control unit 107 converts (encodes) the number of pixels (resolution) of each frame of video data so as to be smaller than that of the original (video source 108), and then transmits (function on). ) By a predetermined value (for example, 1).

  It should be noted that the present invention is not limited to the configuration instructing the function (encoding rate change) on (1) / off (0) switching as described above, and may be configured to directly instruct the encoding rate value.

  The encoding rate changing unit 101 performs encoding processing corresponding to each instruction (S203, S204) on the target video data (video source 108). In this example, the process is executed (function on) only in the case of an instruction to change to a low rate (S204).

  The above processing is repeated during transmission of the image (frame) group of the target video data. As a result, wireless transmission can be performed at a video rate (transmission rate) corresponding to the degree of congestion (free time rate (α)) at each time point (corresponding to an image) on the time axis.

  On the other hand, in FIG. 1, in the receiver 110, a radio signal (video data 109) input (received) from the antenna 111 passes through a radio receiver 112, a baseband unit 113, and a video decoder 114. Data). The restored signal passes through the image quality improvement unit 118 and the like as necessary, and is sent to the display unit 120 and the like, and the video is displayed (reproduced) on the display unit 120 (screen). The display unit 120 may be externally connected to the receiver 110, may be included in the receiver 110, or may be included in a host device connected to the receiver 110.

  Here, the receiver 110 performs the following process control in accordance with the process control in the transmitter 100 (the transmission rate of the video data 109). When the encoding rate (transmission rate) of the video data 109 has been changed to be low by the processing control in the transmitter 100 (S204), the receiver 110 performs the following processing control. That is, in the receiver 110, the signal (data) from the video decoding unit 114 is passed through the image quality improvement processing unit 118 (super-resolution processing unit 115) through the switching operation of the switches 116 and 117. That is, the super-resolution processing is turned on for the video data. By this super-resolution processing, the image quality of display of the video is improved by recovering (increasing) the resolution of each frame in the video.

  On the other hand, when the encoding rate (transmission rate) of the video data 109 is increased by the processing control in the transmitter 100 (S203), the receiver 110 receives a signal (data) from the video decoding unit 114. ) Is prevented from passing through the image quality improvement processing unit 118 (super-resolution processing unit 115) through the switching operation of the switches 116 and 117. That is, the super-resolution processing is turned off for the video data.

  As described above, in the receiver 110, when the video data 109 whose rate is changed by the transmitter 100 is received, it can be displayed with improved (recovered) image quality. Otherwise, the high-quality video data 109 is displayed as it is. Can be obtained and displayed. In either case, it is possible to avoid low image quality and failure in the received video display.

  In this system, in the wireless transmission path (wireless section) between the transmitter 100 and the receiver 110, the wireless frequency to be used is also used by other peripheral devices (with interference), so there is little space and transmission (transmission) is possible. When the data rate is limited and cannot be sufficiently secured, the transmission data amount is reduced by reducing the transmission rate in the wireless section and wirelessly transmitting (reducing congestion). Then, after the deterioration of the image quality of the video data is improved (recovered) by passing it through the image quality improvement unit 118 (super-resolution processing unit 115) on the receiving side (receiver 110), video display (reproduction) is performed. can do. Also, in this system, when there is little congestion in the radio frequency to be used in the radio section and a sufficient data rate can be ensured, the transmission rate is set high so that the image quality of the video is not lowered as much as possible. The receiving side (receiver 110) can display (reproduce) video with the same image quality as that of the transmitting side (transmitter 100). As described above, it is possible to suppress or improve deterioration of the quality of a display image or the like on the reception side (receiver 110) according to the communication environment (wireless transmission path condition or the like).

  Although not particularly described in the configuration of FIG. 1, the receiver 110 has a control unit that performs switching (super-resolution processing function on / off) control and the like of the switches 116 and 117 as in the transmitter 100 side. You may prepare. In the configuration of FIG. 1, the receiver 110 is configured to perform function ON / OFF control by hardware and circuit by switching the switches 116 and 117. It is good also as a structure to perform.

  In addition, the control configuration for switching between two states, such as high / low transmission rate and function on / off, is not limited to this. For example, a configuration in which a plurality of states are switched in stages may be employed.

  In addition, although the transmitter 100 is configured to observe the transmission start and end timings (transmission timing and time of other devices) of all the peripheral devices, the present invention is not limited to this, and for example, the receiver 110 observes the transmission timing of the other devices and A configuration in which the result is transmitted to the transmitter 100 (a configuration in which the receiver side detects a wireless transmission path condition and controls a transmission rate) may be employed.

(Embodiment 2)
Next, the radio | wireless communications system of Embodiment 2 of this invention is demonstrated using FIG. FIG. 3 shows a functional block configuration of transmitter 300 of the wireless communication system according to the second embodiment. As a main difference from the above-described embodiment, the transmitter 300 prepares and stores video data (301, 302) of different rates in the memory 304 in advance and uses them by switching the switch 303 or the like. is there. The receiving side (receiver 110) has the same configuration as that described above.

  The overall flow of the processing operation and the like of this system will be described with reference to FIG. The transmitter 300 has video data {encoded video data A301, B302} encoded (encoded) at different encoding rates in advance in the memory 304. For example, data A301 with a high coding rate and data B302 with a low coding rate. The transmitter 300 switches either of these data (301, 302) by the switch 303 in accordance with an instruction (A3) from the control unit 107, and transmits the antenna via the baseband unit 102 and the wireless transmission unit 103. Sent from 104.

  As in the first embodiment, the control unit 107 is notified of the transmission timing (A1) of the transmitter 300 (own device) from the wireless transmission unit 103, and received by the antenna 105 from the wireless reception unit 106. The transmission timing (A2) of the other device (which uses the same frequency as the own device) is notified. Then, the control unit 107 selects and determines which of the video data (301, 302) is to be transmitted from the degree of congestion on the time axis (free time ratio (α)) in the radio frequency used in the radio transmission path, The corresponding switching control is performed.

  In this system, for example, in the transmitter 300, when the transmission opportunity by CSMA / CA is not sufficiently obtained due to radio interference from the peripheral device, the encoded video data B302 encoded at a low encoding rate is used. The encoded video data A301 encoded at a high encoding rate can be transmitted to the receiver 110. The receiver 110 that receives the video data transmitted from the transmitter 300 has the same configuration as that of the first embodiment, and only when the encoded video data B302 having a low encoding rate is received, the image quality improving unit 118 ( The processing of the super-resolution processing unit 115) can be turned on, and the image quality can be improved (recovered) and displayed.

(Embodiment 3)
Next, the radio | wireless communications system of Embodiment 3 of this invention is demonstrated using FIG. FIG. 4 shows a functional block configuration of transmitter 400 of the wireless communication system according to the third embodiment. As a part mainly different from the above-described embodiment, the transmitter 300 includes a video encoding unit 402 that performs encoding (encoding processing) at an instructed rate. The receiving side (receiver 110) has the same configuration as that described above.

  The overall flow of the processing operation and the like of this system will be described with reference to FIG. The transmitter 400 of this system has video data (video source) 401 stored in advance, and the video encoding unit 402 encodes this. At this time, the video encoding unit 402 receives an instruction of the encoding rate from the control unit 107 by the signal (A3), and performs encoding at an encoding rate (resolution or the like) according to the instruction. The encoded video data is transmitted from the antenna 104 via the baseband unit 102 and the wireless transmission unit 103.

  As in the first embodiment, the control unit 107 grasps the wireless transmission path condition (congestion degree) from the own device transmission timing (A1) and the other device transmission timing (A2), and based on this, the video coding unit 402 An encoding rate is determined, and instruction / switching is performed by a signal (A3).

  As described above, the transmitter 400 of this system transmits video data at an encoding rate corresponding to the wireless transmission path condition, and the receiver 110 improves image quality according to the rate of the received video data, as in the above-described embodiment. The processing (super-resolution processing) can be turned on to improve (recover) the image quality and display.

(Embodiment 4)
Next, a radio communication system according to the fourth embodiment of the present invention will be described with reference to FIGS. FIG. 5 shows a functional block configuration of receiver 510 of the wireless communication system according to the fourth embodiment. As a main difference from the above-described embodiment, the receiver 510 switches processing of the image quality improvement unit 118 (super-resolution processing unit 115) in accordance with a signal from the video decoding unit 114. The transmitting side (transmitter 100 or the like) has the same configuration as that described above.

  The overall flow of the processing operation and the like of this system will be described with reference to FIG. It is assumed that the receiver 510 of this system receives the video data 109 transmitted from the transmitter 100. The receiver 510 restores (decodes) the wireless signal (video data 109) input from the antenna 111 into a video signal (data) through the wireless reception unit 112, the baseband unit 113, and the video decoding unit 114. The restored (decoded) video (decoded video data) is sent to the display unit 120 or the like through the image quality improvement unit 118 as necessary, as in the above-described form.

  The video decoding unit 114 obtains the rate information of the target video data from the decoded video data. Here, the format of the video data 109 is MPEG, for example. In the video decoding unit 114, for example, information on the number of pixels, that is, resolution (resolution in frame units) of decoded video data, such as pixel number information and image rate information in a sequence header in MPEG video data (stream data). The information of the image rate, that is, the frame rate (the number of frames per unit time) can be obtained.

  Here, in the video decoding unit 114, when the resolution of the image (frame) of the decoded video data is equal to or lower than a predetermined threshold value, the video decoding unit 114 passes the super-resolution processing unit 115 of the image quality improvement unit 118 (super-resolution processing). The image resolution of the video is restored. On the other hand, if it is higher than the threshold, the super-resolution processing unit 115 of the image quality improvement unit 118 is not passed (super-resolution processing is turned off). The switching is performed, for example, by giving a super-resolution processing switching signal (B1) from the video decoding unit 114 to the switches 116 and 117.

  As described above, the receiver 510 can recover the resolution when receiving the video data whose resolution is lower than the setting, and can obtain and display the video data having the received resolution otherwise. Note that the receiver 510 may include a control unit for controlling the processing.

  The processing control in the receiver 510 will be described in further detail with reference to FIG. FIG. 6 shows a process flow of the switching instruction operation of the image quality improvement process (super-resolution process) based on the rate information in the receiver 510.

  In S601, the video decoding unit 114 obtains decoded video data from the input video stream data, and extracts information on the number of pixels (P) from the header (others may extract frame rate information and the like). ). In S602, the video decoding unit 114 compares the extracted number of pixels (frame resolution) (P) with a predetermined threshold value. When the number of extracted pixels (P) is smaller than the threshold value (S602-Y), the signal (B1) is instructed to turn on the super-resolution processing for the decoded video data in S603. On the other hand, when the number of pixels (P) is equal to or greater than the threshold value (S602-N), an instruction is given to turn off the super-resolution processing in S604.

  By repeating these processes during reception of the video stream, it is possible to display the image by restoring the image quality by super-resolution processing according to the resolution of the received video (image) at each time point.

  As described above, the receiver 510 of the present system receives the video data transmitted at the encoding rate corresponding to the wireless transmission path condition, and improves the image quality (particularly, the frame resolution) in the same manner as described above. The video can be displayed after recovery.

  For example, the receiver 510 receives control information (encoding rate information) from the transmitter 100 separately from the video stream data, and the receiver 510 refers to the rate information, for example. In addition, a configuration for switching image quality improvement processing is also possible.

(Embodiment 5)
Next, a radio communication system according to the fifth embodiment of the present invention will be described with reference to FIGS. FIG. 7 shows a functional block configuration of the wireless communication system according to the fifth embodiment. As a main difference from the above-described embodiment, in the transmitter 700, the baseband unit 702 inputs a signal (A3) of an instruction (control information) from the control unit 107 and multiplexes the data with the receiver 710. The baseband unit 713 separates data and control information, and performs switching control of image quality improvement processing according to the separated control information.

  The overall flow of the processing operation and the like of this system will be described with reference to FIG. The transmitter 700 of this system performs coding rate change on the input video source at the coding rate changing unit 101 and adjusts the amount of video data to be transmitted, and then the baseband unit 702 and the wireless transmission unit 103. Through the antenna 104.

  As in the first embodiment, the control unit 107 gathers information on its own transmission timing from the wireless transmission unit 103 (A1) and information on other device transmission timing from the wireless reception unit 106 (A2). , Grasp the degree of congestion (free time rate (α)) related to the radio frequency to be used. The control unit 107 instructs the coding rate changing unit 101 on the coding rate corresponding to the degree of congestion by a signal (A3). For example, the control unit 107 encodes a high coding rate when the idle time rate (α) is larger than a threshold value during the latest fixed time, and a low coding rate when it is equal to or smaller than the threshold value. Instructs the rate changing unit 101.

  In this system, the control unit 107 not only notifies the coding rate changing unit 101 of the determined coding rate, but also notifies the baseband unit 702. The baseband unit 702 multiplexes the encoded video data (encoded video data) input from the encoding rate changing unit 101 and the encoding rate information (A3) input from the control unit 107. To the wireless transmission unit 103.

  Here, in the control unit 107 and the baseband unit 702, the control information includes not only the determined encoding rate itself (A3a) but also whether the encoding rate is kept low due to congestion at the radio frequency to be used. The information (A3b) that conveys information may also be included or multiplexed. The information (A3b) can be regarded as information on the function on / off switching instruction control of the receiving side (receiver 710).

  From the above, in the transmitter 700, the signal 709 obtained by multiplexing the encoded video data of the encoding rate according to the degree of congestion and the control information (A3a, A3b in this example) according to the degree of congestion as in the above-described form. Wireless transmission.

  On the other hand, in the receiver 710 of this system, the wireless signal (signal 709) input from the antenna 111 is restored (decoded) to a video signal (video data) through the wireless receiving unit 112, the baseband unit 713, and the video decoding unit 114. ) Here, of the control information (A3a, A3b) multiplexed in the video data, information (A3b) indicating whether or not the video coding rate has been changed by the transmitter 700 is changed by the baseband unit 713. It can be obtained by separating the coding rate information (A3a). The baseband unit 713 controls the on / off of the super-resolution processing by giving this information (A3a) to the switches 116 and 117 of the image quality improvement unit 118 (super-resolution processing unit 115).

  As described above, the receiver 710 receives the video data transmitted at the encoding rate according to the wireless transmission path condition, and displays the video after improving (recovering) the image quality accordingly. Can do.

  The function switching operation of the receiver 710 will be described in more detail with reference to FIG. In S801, the baseband unit 713 separates the coding rate information (A3) from the signal received from the signal 709 multiplexed and transmitted by the transmitter 700, thereby receiving an image (frame) of the video data being received. The number of pixels (P) and the like can be grasped. In S802, the baseband unit 713 compares, for example, the number of pixels (P) in the coding rate information with a predetermined threshold value. When the number of pixels (P) is smaller than the threshold (S802-Y), the baseband unit 713 turns on image quality improvement processing (super-resolution processing) on the decoded video data from the video decoding unit 114 in S803. Instructed by the signal (B1). On the other hand, when the number of pixels (P) is equal to or greater than the threshold value (S802-N), the baseband unit 713 instructs the signal (B1) to turn off the image quality improvement processing (super-resolution processing) in S804. .

  By repeating these processes during the reception of the video stream data, the image quality can be restored by super-resolution processing and displayed according to the resolution of the received video (image) at each time point.

(Embodiment 6)
Next, the radio | wireless communications system of Embodiment 6 of this invention is demonstrated using FIG. FIG. 9 shows a functional block configuration of receiver 910 of the wireless communication system according to the sixth embodiment. The image quality improvement unit 918 includes a resolution conversion unit (super-resolution processing unit) 911 and a frame number conversion unit (frame rate processing unit) 912 as mainly different from the above-described form.

  The overall flow of the processing operation and the like of this system will be described with reference to FIG. It is assumed that the receiver 910 of this system receives the video data 109 transmitted from the transmitter 100 or the like similar to the above-described form. The receiver 910 restores (decodes) the radio signal input from the antenna 111 into a video signal (video data) through the radio reception unit 112, the baseband unit 113, and the video decoding unit 114. Here, in the receiver 910, when the video encoding rate has been changed to a low value by the transmitter 100, the image quality improvement processing is performed by the image quality improvement unit 918. Otherwise, the image quality recovery processing is performed. Not performed.

  In this system, the image quality improvement unit 918 has a resolution conversion process (super-resolution process) by the resolution conversion unit 911 and a frame rate conversion process by the frame number conversion unit 912. The resolution conversion unit 911 recovers (improves) the image quality in units of frames by performing processing (super-resolution processing) that increases the number of pixels (frame resolution) of one frame in the video data (frame group). Also, the frame number conversion unit 912 recovers (improves) the image quality of the moving image by performing a process of increasing the number of frames (frame rate) by complementing the frames in the video data (frame group).

  Whether the resolution conversion unit 911 is routed (turned on) or whether the frame number conversion unit 912 is routed (turned on) can be switched. That is, the combination of ON / OFF of each process of the image quality improvement process can be appropriately selected from both off, only one on, both on.

  In addition, the degree of each image quality improvement process (the degree of change in resolution and frame rate, the processing parameters, etc.) may be appropriately controlled. In addition, the switching (selection) may be configured to be instructed by the transmitter 100 side or may be determined by the receiver 910 side.

  As described above, the receiver 910 can turn on / off the recovery of the frame resolution and / or the number of frames when receiving video data whose video encoding rate is lower than the setting, and otherwise, it remains as it is. Video data can be obtained.

  As described above, the receiver 910 receives the video data transmitted at the encoding rate according to the wireless transmission path condition, and displays the video after improving (recovering) the image quality accordingly. Can do.

(Embodiment 7)
A radio communication system according to the seventh embodiment of the present invention will be described with reference to FIGS. FIG. 10 shows a functional block configuration of receiver 1010 of the wireless communication system according to the seventh embodiment. As a part mainly different from the above-described embodiment, the receiver 1010 includes a control unit 1011, and based on the information (B 1) such as the coding rate and the performance information (C 1) from the display unit 1020, the image quality improvement unit 1018. The process is switched on / off.

  The overall flow of the processing operation and the like of this system will be described with reference to FIG. It is assumed that the receiver 1010 of this system receives the video data 109 transmitted from the transmitter 100 similar to that described above. The receiver 1010 restores (decodes) the radio signal input from the antenna 111 into a video signal (video data) through the radio reception unit 112, the baseband unit 113, and the video decoding unit 114. Here, if the video encoding rate has been changed to a low value by the transmitter 100, the image quality recovery process is performed, and if not, the image quality recovery process is not performed. The receiver 1010 includes, as the image quality improvement unit 1018, for example, a resolution conversion unit 911 and a frame number conversion unit 912 as in the above-described form.

  The video data received by the receiver 1010 is displayed (reproduced) as video on the display unit 1020 connected to the receiver 1010, for example. In this example, the receiver 1010 and the display unit 1020 are provided. However, the present invention is not limited thereto, and the configuration in which the receiver 1010 has the function of the display unit 1020, or conversely, the display unit 1020 is the receiver 1010. A configuration having a function is also possible.

  In this system, the display unit 1020 notifies the receiver 1010 of the performance of the display unit 1020, that is, information such as the resolution and frame rate of reproducible video data (performance information C1). Alternatively, the performance information C1 of the display unit 1020 is acquired from the receiver 1010. Alternatively, for example, once the display unit 1020 is connected to the receiver 1010, the performance information C1 is obtained to the control unit 1011. When another display unit 1020 is connected, the performance information C1 is similarly obtained. Is obtained.

  The control unit 1011 of the receiver 1010 receives the video information from the performance information C1 of the display unit 1020 and information (B1) such as the resolution and frame rate of the received video data (decoded video data) notified from the video decoding unit 114. Whether or not to apply the processing of the image quality improvement unit 1018 to the data (whether it passes through the resolution conversion unit 911 and / or whether it passes through the frame number conversion unit 912) is determined and determined Is applied to the switch of the image quality improvement unit 1018 or the like.

  The determination of the switching control can be realized as follows, for example. When the frame resolution of the received video data is lower than the upper limit of the resolution that can be displayed by the display unit 1020, the control unit 1011 switches to pass through the resolution conversion unit 911, otherwise, the resolution conversion unit Switch not to go through 911. In addition, the control unit 1011 switches to the frame number conversion unit 912 when the frame rate of the received video data is lower than the upper limit of the frame rate that can be displayed by the display unit 1020. Switch not to go through.

  The processing control (function switching operation) of the receiver 1010 of this system will be described in more detail using FIG. In step S1101, the control unit 1011 receives, from the display unit 1020, as the performance information C1, the upper limit value (maximum resolution information c1) of the number of pixels (frame resolution) that can be displayed on the display unit 1020 and the upper limit of the frame rate that can be displayed. Information on the value (maximum frame rate c2) is acquired. In S1102, the video decoding unit 114 extracts information on the number of pixels (P) and information on the frame rate (Q) from the video stream data (for example, header).

  In step S <b> 1113, the control unit 1011 can display the extracted number of pixels (frame resolution) (P) on the display unit 1020 with the number of pixels (p) as a result when the resolution conversion unit 911 performs super-resolution processing. The upper limit value (maximum resolution information c1) of the number of pixels is compared. When the number of pixels (p) after the super-resolution processing is larger than the upper limit value (c1) (S1103-Y), the super-resolution of the decoded video data is performed from the control unit 1011 to the image quality improvement unit 1018 in S1104. Instructs to turn off processing. On the other hand, when the number of pixels (p) after the super-resolution processing is equal to or less than the upper limit value (c1) (S1103-N), the super-resolution processing is turned on from the control unit 1011 to the image quality improvement unit 1018 in S1105. To instruct.

  Similarly, in S1106, the frame rate (q) obtained by subjecting the frame rate (Q) extracted in S1102 to frame conversion processing by the frame number conversion unit 912 and the display unit 1020 can display the result. The upper limit value of the frame rate (maximum frame rate c2) is compared. When the converted frame rate (q) is larger than the upper limit value (c2) (S1106-Y), in step S1107, the frame rate conversion process for the decoded video data is turned off from the control unit 1101 to the image quality improvement unit 1108. To instruct. On the other hand, when the frame rate (q) after the frame rate conversion is equal to or lower than the upper limit value (c2) (S1106-N), the frame rate conversion process is turned on from the control unit 1101 to the image quality improvement unit 1108 in S1108. To instruct.

  By repeating these switching processes while receiving the video stream data, the frame resolution and frame rate of the received video at each time point and the resolution upper limit (c1) and frame rate upper limit (c2) that can be displayed on the display unit 1020 are displayed. Accordingly, restoration (improvement) of image quality by super-resolution processing and / or frame rate conversion processing can be turned on / off, respectively. The order of the on / off processing is an example.

  As described above, the receiver 1010 can appropriately select the resolution of the video and the recovery of the frame rate according to the encoding rate of the received video data and the display performance of the display unit 1020. Can be displayed with high image quality.

(Embodiment 8)
Next, the radio | wireless communications system of Embodiment 8 of this invention is demonstrated using FIG. FIG. 12 shows the overall configuration of the wireless communication system according to the eighth embodiment. This is a case where video data is transmitted from the transmitter 1200 to each of a plurality of receivers 1210A to 1210C, which is mainly different from the above-described embodiment. Note that the above-described embodiment is the same as the present embodiment when viewed as a system configuration having a plurality of receivers instead of a single receiver.

  In this system, the wireless communication apparatus includes a transmitter 1200 and a receiver 1210 (1210A, B, C). The transmitter 1200 has the same configuration as the transmitter 100 of Embodiment 1 (FIG. 1), for example. The receiver 1210 has the same configuration as the receiver 1010 of Embodiment 7 (FIG. 10), for example. In addition, the display unit 1220 connected to each of the receivers 1210A to 1210 includes 1220 (1220A, B, C). Display unit 1220 has the same configuration as display unit 1020 in the seventh embodiment (FIG. 10), for example. As described above, the receiver 1210 and the display unit 1220 may be integrated. In this example, a case where one transmitter 1200 and three receivers 1210 are provided is shown.

  The transmitter 1200 (for example, the control unit 1201) detects the state of a wireless transmission path including a plurality of other apparatuses (receivers 1210) in the surrounding environment, and changes / adjusts the transmission rate of the wireless section according to the detection. Control. That is, the transmitter 1200 detects (calculates) the degree of congestion (free time ratio (α)) on the time axis based on the situation of each of the receivers 1210A to 12C using the same radio frequency as that of the own device, and responds accordingly. Thus, the encoding rate of video data or the like transmitted (transmitted) to the communication partner device (for example, each of the receivers 1210A to 1210C) is changed / adjusted.

  Each of the receivers 1210A to 1210C receives video data and the like transmitted from the transmitter 1200. Each receiver 1210A-C (for example, the control unit 1211) improves the image quality of the received video data according to the performance of the corresponding display units 1220A-C (resolution of displayable video, frame rate, etc.). Control on / off of processing. The image quality improvement processing is, for example, resolution conversion processing (super-resolution processing) and frame number conversion processing by each image quality improvement unit 1212.

  As described above, by changing the data rate of the wireless section in accordance with the situation including other devices in the surrounding environment, it is possible to prevent the failure of the video on the receiving side (each receiver 1210A-C). In addition, by converting the image quality (resolution, frame rate, etc.) of the received video data according to the performance of each display unit 1220A-C connected to each receiver 1210A-C, the data rate in the wireless section is lowered. Even in this case, image quality can be improved (recovered) on the receiving side (respective receivers 1210A to 1210C) and displayed appropriately.

  When video data is transmitted from the transmitter 1200 to the receivers 1210A to 1210C at the same rate and the performance of the display units 1220A to 12C of the receivers 1210A to 12C is different, the image quality is displayed according to the performance. So it is efficient.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention is applicable to a wireless communication system.

It is a figure which shows the functional block structure of the radio | wireless communications system which is Embodiment 1 of this invention. It is a figure which shows the processing flow of the switching control in the transmitter in the radio | wireless communications system of Embodiment 1 of this invention. It is a figure which shows the structure of the transmitter in the radio | wireless communications system which is Embodiment 2 of this invention. It is a figure which shows the structure of the transmitter in the radio | wireless communications system which is Embodiment 3 of this invention. It is a figure which shows the structure of the receiver in the radio | wireless communications system which is Embodiment 4 of this invention. It is a figure which shows the processing flow of the switching control in the receiver in the radio | wireless communications system of Embodiment 4 of this invention. It is a figure which shows the functional block structure of the radio | wireless communications system which is Embodiment 5 of this invention. It is a figure which shows the processing flow of the switching control in the receiver in the radio | wireless communications system of Embodiment 5 of this invention. It is a figure which shows the structure of the receiver in the radio | wireless communications system which is Embodiment 6 of this invention. It is a figure which shows the structure of the receiver in the radio | wireless communications system which is Embodiment 7 of this invention. It is a figure which shows the processing flow of the switching control in the receiver in the radio | wireless communications system of Embodiment 7 of this invention. It is a figure which shows the whole structure in the radio | wireless communications system which is Embodiment 8 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100,300,400,700,1200 ... Transmitter, 101 ... Coding rate change part, 102 ... Baseband part, 103 ... Wireless transmission part, 104 ... Antenna, 105 ... Antenna, 106 ... Wireless reception part, 107, 1201 ... Control unit, 108 ... Video source, 109 ... Video data (transmission radio signal), 110, 510, 710, 910, 1010, 1210A-C ... Receiver, 111 ... Antenna, 112 ... Radio reception unit, 113 ... Baseband 114, video decoding unit, 115 ... super-resolution processing unit, 116, 117 ... switch, 118, 918, 1018, 1212 ... image quality improvement unit, 120, 1020, 1220A to C ... display unit, 301 ... encoded video Data A, 302 ... encoded video data B, 303 ... switch, 304 ... memory, 401 ... video data (video source , 402 ... Video encoding unit, 702 ... Baseband unit, 709 ... Signal, 713 ... Baseband unit, 911 ... Resolution conversion unit (super-resolution processing unit), 912 ... Frame number conversion unit, 1011, 1211 ... Control unit .

Claims (11)

A wireless communication system having a transmitter and a receiver and transmitting data such as video wirelessly between the transmitter and receiver,
The transmitter includes a control unit that performs processing control to change a coding rate of the first video data to be transmitted to the receiver according to a state of a wireless transmission path between the transmitter and the receiver. And
The receiver includes an image quality improvement unit that performs an image quality improvement process including a super-resolution process for increasing resolution by interpolating between pixels in video data, and receives the first video received from the transmitter For the data, in accordance with the encoding rate, performs processing control to perform the image quality improvement processing,
When the state of the wireless transmission path is not good, in the transmitter, the control unit transmits the first video data by changing the coding rate to a low value, and accordingly, in the receiver, A wireless communication system, wherein the image quality improvement processing by the image quality improvement unit is turned on. The wireless communication system according to claim 1, wherein
In the environment including the other transmitters using the radio frequency included in the radio frequency channel used by the own device, the transmitter transmits information on the wireless transmission timing of the own device and the other transmitter obtained by carrier sense. A wireless communication system comprising: means for detecting or measuring the state of the wireless transmission path as a degree of congestion on the time axis or an idle time rate by referring to the wireless transmission timing information of The wireless communication system according to claim 1, wherein
The control unit of the transmitter prepares each encoded video data having a plurality of different encoding rates in a memory in advance, and selects the first video data according to the state of the wireless transmission path from these. A wireless communication system, comprising: selecting data to be transmitted as video data. The wireless communication system according to claim 1, wherein
The control unit of the transmitter determines the encoding rate according to the state of the wireless transmission path, and transmits data obtained by encoding video data at the encoding rate as the first video data. A wireless communication system characterized by the above. The wireless communication system according to claim 1, wherein
The receiver refers to information on a coding rate of the video data from data obtained by decoding the received first video data, and switches and controls whether to perform the image quality improvement processing; A wireless communication system. The wireless communication system according to claim 1, wherein
In addition to the first video data, the control unit of the transmitter multiplexes the information of the coding rate of the first video data or transmits it to the receiver as another data,
The receiver switches whether to perform the image quality improvement processing by separating the encoding rate information of the first video data from the transmitter or receiving it as separate data. A wireless communication system. The wireless communication system according to claim 1, wherein
The receiver performs, as the image quality improvement processing by the image quality improvement unit, a combination of super-resolution processing for each frame and processing for increasing the frame rate by increasing the number of frames by interpolating between frames. A wireless communication system characterized by the above. The wireless communication system according to claim 7, wherein
The receiver includes a control unit that controls on / off or the degree of the image quality improvement processing according to the performance of a display unit that displays the received first video data as video. Wireless communication system. The wireless communication system according to claim 1 or 8,
A plurality of the receivers for receiving the first video data transmitted from the transmitter;
Each receiver is connected or built in a display unit that displays the received first video data as video,
Each wireless communication system performs switching control as to whether or not to perform the image quality improvement processing according to the performance of the display unit. The transmitter in a wireless communication system having a transmitter and a receiver and transmitting data such as video wirelessly between the transmitter and receiver,
The transmitter includes a control unit that performs processing control to change a coding rate of the first video data to be transmitted to the receiver according to a state of a wireless transmission path between the transmitter and the receiver. And
The receiver includes an image quality improvement unit that performs an image quality improvement process including a super-resolution process for increasing resolution by interpolating between pixels in a frame unit for video data, and the first video received from the transmitter For the data, in accordance with the encoding rate, performs processing control to perform the image quality improvement processing,
When the state of the wireless transmission path is not good, in the transmitter, the control unit transmits the first video data by changing the encoding rate to be low, and correspondingly, in the receiver, A transmitter characterized by turning on the image quality improvement processing by the image quality improvement unit. The receiver in a wireless communication system having a transmitter and a receiver and transmitting data such as video wirelessly between the transmitter and receiver,
The transmitter includes a control unit that performs processing control to change a coding rate of the first video data to be transmitted to the receiver according to a state of a wireless transmission path between the transmitter and the receiver. And
The receiver includes an image quality improvement unit that performs an image quality improvement process including a super-resolution process for increasing resolution by interpolating between pixels in video data, and receives the first video received from the transmitter For the data, in accordance with the encoding rate, performs processing control to perform the image quality improvement processing,
When the state of the wireless transmission path is not good, in the transmitter, the control unit transmits the first video data by changing the encoding rate to be low, and correspondingly, in the receiver, A receiver characterized by turning on the image quality improvement processing by the image quality improvement unit.

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