JP5742342B2 - Portable terminal device and image correction program - Google Patents

Description

  The present invention relates to a portable terminal device capable of viewing a short distance broadcast using one segment of a terrestrial digital television broadcast.

  As television broadcasting for mobile phones, television broadcasting using one segment of terrestrial digital television broadcasting (hereinafter referred to as one-segment broadcasting) has become widespread. As an example of one-segment broadcasting, “short distance broadcasting by a small-scale broadcasting station” using a weak radio wave covering a narrow reception area with a radius of several meters to several tens of meters has been proposed.

  The specifications of short-distance broadcasting by small-scale broadcasting stations are basically the same as general one-segment broadcasting (other than short-distance broadcasting). Therefore, the user can view a short-distance broadcast by a small-scale broadcast station using a mobile phone capable of receiving a one-segment broadcast. Such short-distance broadcasting by a small-scale broadcasting station can provide the latest programs suitable for a region or a store such as a department store, a convenience store, a restaurant, etc. by utilizing the characteristics of weak radio waves.

  Here, an example of the conventional short distance broadcast viewing process will be specifically described. In the mobile phone, a television broadcast is received by the video playback tuner, and the received broadcast is displayed on the screen, while the channel is scanned by the search tuner to detect other broadcast waves. When a broadcast wave is detected by the search tuner, the mobile phone further compares the channel information of the detected broadcast wave with the channel information stored in the general broadcast channel storage unit. As a result, if the channel information of the detected broadcast wave is not registered in the general broadcast channel storage unit, the mobile phone determines that the detected broadcast wave is a short-distance broadcast by a small broadcast station. . Then, the detected broadcast wave channel information is registered in the small-scale broadcast channel storage unit. Thereafter, in the mobile phone, the channel of the video playback tuner is switched to the registered channel for small-scale broadcasting, and the short-distance broadcast video is displayed on the screen. By using such a technique, the user can view, for example, a recommended content broadcast in a store within a predetermined range such as in a store.

JP 2009-182800 A

  However, since the conventional technology uses weak radio waves covering a reception area with a radius of several meters to several tens of meters, the reception state deteriorates while moving in the store, and the image quality deteriorates. There was a problem that the “screen is broken”.

  The disclosed technology has been made in view of the above, and an object of the present invention is to provide a portable terminal device that can prevent image distortion when the reception state of short-distance broadcast deteriorates.

  A mobile terminal device disclosed in the present application is, in one aspect, a mobile terminal device capable of viewing a video broadcast from a broadcast station, and stores a storage unit storing an I picture and a broadcast wave from the broadcast station. When the reception quality of the broadcast wave is monitored and the deterioration of the reception quality is detected, the I picture corresponding to the timing when the deterioration of the reception quality is detected is read from the storage unit, and the read I picture is displayed on the screen. A control unit to be displayed above.

  According to one aspect of the mobile terminal device disclosed in the present application, there is an effect that it is possible to prevent image disturbance when the reception state of the short-distance broadcast deteriorates.

FIG. 1 is a diagram illustrating a configuration example of a mobile phone which is an example of a mobile terminal device. FIG. 2 is a diagram showing an outline of image correction processing in the mobile phone. FIG. 3 is a diagram showing an outline of image correction processing in the mobile phone. FIG. 4 is a flowchart showing image correction processing of the mobile phone. FIG. 5 is a diagram illustrating a criterion for detection within / without a reception area. FIG. 6 is a flowchart showing I picture interpolation processing.

  Embodiments of an image correction program and a mobile terminal device disclosed in the present application will be described below in detail with reference to the drawings. In the following embodiment, a mobile phone is used as an example of the mobile terminal device, but the present invention is not limited to this embodiment. For example, the technology disclosed in the present application can be similarly applied to any device capable of receiving one-segment broadcasting such as a PDA (Personal Digital Assistant), a notebook personal computer, a game machine, and a car navigation system.

  FIG. 1 is a diagram illustrating a configuration example of a mobile phone according to the present embodiment. In FIG. 1, a cellular phone 1 according to the present embodiment performs infrared communication and the like with a processor 11, a terrestrial digital receiving unit 12, a demodulation / separation unit 13, an audio decoding unit 14, an image decoding unit 16, and a data broadcast decoding unit 17. And an external communication unit 18. In addition, these structures can be comprised by CPU (Central Processing Unit), FPGA (Field Programmable Gate Array), etc., for example.

  1, the mobile phone 1 includes a display unit 15 such as an LCD (Liquid Crystal Display), a storage unit 19 having a ROM and a RAM, an antenna 20 for receiving broadcast waves, and a speaker 21. Note that the configuration example of the mobile phone 1 shown in FIG. 1 lists the configurations related to the processing of the present embodiment for convenience of explanation, and does not represent all the configurations that realize the mobile phone function.

  The processor 11 executes the image correction program and the like of the present embodiment, and performs a terrestrial digital reception unit 12, a demodulation separation unit 13, an audio decoding unit 14, a display unit 15, an image decoding unit 16, a data broadcast decoding unit 17, an external communication The unit 18 and the storage unit 19 are controlled.

  The terrestrial digital receiver 12 receives broadcast waves via the antenna 20 and performs processing such as conversion into baseband signals and A / D conversion. The decoding / separating unit 13 performs processing such as demodulation and error correction decoding on the received signal to restore a TS (Transport Stream) packet. This TS packet includes data information such as captions and program information in addition to video and audio. Further, the decoding / separating unit 13 separates the TS packets into video, audio, and data broadcasting TS packets.

  Further, the audio decoding unit 14 generates an audio signal from the separated TS packet and outputs the audio from the speaker 21. The image decoding unit 16 generates a video signal from the separated TS packet. The data broadcast decoding unit 17 generates a data broadcast signal from the separated TS packet. The display unit 15 displays an image obtained by superimposing a video signal and a data broadcast signal, for example.

  The storage unit 19 stores various programs such as the image correction program of this embodiment in advance. The processor 11 reads and executes these programs. The storage unit 19 stores an I picture for I picture interpolation processing, which will be described later.

  Next, an overview of image correction processing in the mobile phone 1 of the present embodiment will be described. 2 and 3 are diagrams showing an outline of the image correction processing in the mobile phone 1. It is assumed that the mobile phone 1 is a mobile phone that can receive one-segment broadcasting. Moreover, since the specifications of the short-distance broadcast by the small-scale broadcasting station 2 are the same as those of the general one-segment broadcast, the user can view the short-distance broadcast using the mobile phone 1 that can receive the one-segment broadcast. In short-distance broadcasting, it is assumed that the same video is repeatedly broadcast.

  For example, when the mobile phone 1 is located in the short-distance broadcast receiving area 3 by the small-scale broadcasting station 2, if the user performs an operation to instruct the mobile phone 1 to view the short-distance broadcast, The telephone 1 starts to receive a short-distance broadcast wave. The mobile phone 1 acquires an I picture (Intra picture) and a B / P picture (Predictive picture / Bi-directional predictive picture) as video data by decoding the received signal obtained via the antenna 20 ( 2, FIG. 3, S1). In S1 of FIG. 3, an example of video data (see the upper part of FIG. 3) obtained by decoding is described. Specifically, an example in which the frame rate representing the number of frames per second is 15 FPS and the GOP (Group Of Pictures) length is 5 is described. In this case, the interval to the next I picture is “1 ÷ 15 × 5 = 0.33 seconds”. The cellular phone 1 displays video on the display unit 15 using the video data (I picture, B / P picture) (see video data after application of the image correction program in S1 in FIG. 3).

  On the other hand, the mobile phone 1 uses the infrared communication function by the external communication unit 18 to start receiving short-distance broadcasts. Requests batch transfer of I pictures. Then, as a response, the requested I picture is collectively received from a computer installed in the small-scale broadcasting station 2 using the infrared communication function of the infrared communication unit 18 (S2 in FIG. 2). In this embodiment, IrSimple is adopted as an example of the infrared communication function. This I picture reception process may be executed autonomously on the mobile phone 1 side under the control of the processor 11, or may be executed when the mobile phone 1 is placed in the cradle. Good. In this embodiment, IrSimple is used when receiving an I picture. However, the present invention is not limited to this, and infrared communication other than IrSimple or near field communication such as Bluetooth (registered trademark) may be used.

  When the reception of the I picture by S2 is completed, the mobile phone 1 starts monitoring the reception quality of the broadcast wave. This monitoring may be performed at all times by the processor 11 controlling the terrestrial digital reception unit 12 or periodically (every 5 seconds or the like) by the processor 11 controlling the terrestrial digital reception unit 12. It is good as well.

  In this state, for example, when the user of the mobile phone 1 starts to move out of the reception area 3 (FIG. 2, FIG. 3, S3), the mobile phone 1 detects video data at the timing when the reception quality deterioration is detected. Is interpolated with the I picture received in S2 (FIGS. 2, 3, and S4). For example, when the reception quality deteriorates, video data cannot be obtained as shown in FIG. 3 (see the decoded video data at the top of FIG. 3), and the video on the display unit 15 of the mobile phone 1 is disturbed. (See FIGS. 2 and 3). Therefore, in the cellular phone 1 according to the present embodiment, video data after the timing when the deterioration of the reception quality is detected is interpolated with an I picture (I picture having the same broadcast frame number) received in advance (see FIG. 3, S4-1). The interpolated I pictures are continuously displayed on the display unit 15 until the frame timing of the next I picture (after 0.33 seconds) (S4-2 in FIG. 3). Thereafter, the mobile phone 1 repeats the above-described interpolation processing at the frame timing of the I picture until the reception quality is recovered and predetermined video data is obtained (FIG. 3, S4-3). Avoid disturbances.

  Thereafter, when recovery of reception quality is detected, the mobile phone 1 ends the interpolation processing and displays a video on the display unit 15 using video data (I picture, B / P picture) obtained by decoding. (FIG. 3, S5). Note that the cellular phone 1 discards the interpolated I-pictures received in S2 at the end of reception of short-distance broadcasting (corresponding to “one-segment end” in FIG. 3).

  Next, the operation of the mobile phone 1 will be specifically described according to a flowchart. FIG. 4 is a flowchart showing the image correction processing of this embodiment.

  For example, when the user performs an operation for receiving a one-segment broadcast on the mobile phone 1, the processor 11 stores the channel ID designated by the user's operation in the storage unit 19 and stores the one-segment broadcast in the terrestrial digital reception unit 12. Broadcast wave reception is started (S11).

  When the one-segment broadcasting being received is a short-distance broadcast, the processor 11 uses the infrared communication function of the infrared communication unit 18 to generate a video that is repeatedly broadcast to a computer installed in the small-scale broadcasting station 2. Requests batch transfer of corresponding I pictures. As a response, the processor 11 uses the infrared communication function of the infrared communication unit 18 to collectively receive the requested I pictures from the computer installed in the small-scale broadcasting station 2 and stores them in the storage unit 19. .

  Further, the processor 11 monitors whether the terrestrial digital receiver 12 is within the reception area while receiving the short-distance broadcast by the small-scale broadcasting station 2 or other general one-segment broadcast (S11). . That is, the processor 11 monitors the reception quality of the received signal, determines that it is within the reception area when the predetermined reception quality is satisfied, and determines that it is out of the reception area when the predetermined reception quality is not satisfied. FIG. 5 is a diagram illustrating a criterion for detection within / without a reception area. In FIG. 5, as an example, the reception quality is CNR (Carrier to Noise ratio). The processor 11 determines that it is out of the reception range when this CNR is less than a threshold value (for example, 30 dB). In this embodiment, the CNR is used as the reception quality, but the present invention is not limited to this.

  For example, in the processing by S12, when the processor 11 determines that the signal is within the reception range (S12, Yes), the terrestrial digital reception unit 12 receives the received signal after A / D conversion based on the transfer instruction from the processor 11 Transfer to the demodulator / separator 13. Next, the demodulation separation unit 13 performs processing such as OFDM (Orthogonal Frequency Division Multiplexing) demodulation and error correction decoding on the received signal under the control of the processor 11 to restore the TS packet (S13). Then, the demodulation / separation unit 13 separates the restored TS packet into a video / audio packet and a data broadcast packet (S14). Next, the audio decoding unit 14, the image decoding unit 16, and the data broadcast decoding unit 17 decode the separated TS packets under the control of the processor 11 to generate an audio signal, a video signal, and a data broadcast signal, respectively ( S15). After decoding the TS packet, the display unit 15 displays the video under the control of the processor 11 (S16).

  On the other hand, if it is determined in step S12 that the received signal is out of the reception area (S12, No), the processor 11 determines that the broadcast wave being received is a short-distance broadcast based on the reception channel ID stored in the storage unit 19. It is determined whether it is a one-segment broadcasting or other one-segment broadcasting (S17). For example, when the broadcast wave being received is a broadcast wave of one-segment broadcasting other than the short distance broadcast (S17, No), the processor 11 executes the processes of S13 to S16 by the same process as described above. On the other hand, when the broadcast wave being received is a short-distance broadcast wave (S17, Yes), the processor 11 executes the “I picture interpolation” process shown in FIG. 6 (S18). Specifically, the processor 11 first acquires the broadcast frame number at the timing determined to be out of the reception range in S12 (S21), and the I picture corresponding to the same broadcast frame number is stored in the storage unit 19. It is determined whether or not (S22). When an I picture corresponding to the same broadcast frame number is stored in the storage unit 19 (S22, Yes), the processor 11 reads the I picture from the storage unit 19 and reads video data at a timing determined to be out of the reception range. Then, the read I picture is interpolated (S23). Then, the processor 11 continuously displays the interpolated I pictures on the display unit 15 (S16). In addition, when the I picture corresponding to the same broadcast frame number is not memorize | stored in the memory | storage part 19 (S22, No), the processor 11 has memorize | stored the I picture corresponding to the same number in the memory | storage part 19. Until it can be confirmed, the processes of S21 and S22 are repeated.

  The processor 11 repeatedly executes the processes of S12 to S18 while the terrestrial digital receiver 12 is receiving short-distance broadcasting by the small-scale broadcasting station 2 or other general one-segment broadcasting (S11). . The processor 11 discards the I picture for interpolation stored in the storage unit 19 in response to the end of the reception of the short distance broadcast. As a result, the available area can be increased.

  As described above, in this embodiment, the mobile phone collectively receives I pictures of repeatedly broadcast images while receiving a short-distance broadcast wave. When the mobile phone detects the deterioration of the reception quality of the broadcast wave, the I picture (I of the same broadcast frame number) that has received in advance the video data after the timing when the deterioration of the reception quality is detected. (Picture). Thereby, even when the reception state of the short-distance broadcast by the small-scale broadcast station is deteriorated, it is possible to prevent image disturbance on the display.

DESCRIPTION OF SYMBOLS 1 Mobile telephone 2 Small broadcasting station 3 Reception area 11 Processor 12 Terrestrial digital receiving part 13 Demodulation separation part 14 Audio | voice decoding part 15 Display part 16 Image decoding part 17 Data broadcast decoding part 18 External communication part 19 Memory | storage part 20 Antenna 21 Speaker

Claims (4)

In a mobile terminal device capable of viewing video broadcast from a broadcasting station,
A storage unit storing I pictures;
When receiving the broadcast wave from the broadcasting station, the reception quality of the broadcast wave is monitored, and when the deterioration of the reception quality is detected, the reception quality of the reception quality is determined from the storage unit when the deterioration of the reception quality is detected . A control unit for sequentially reading out I pictures corresponding to the timing of the frame in which recovery is detected , and displaying the read out I pictures on the screen;
A portable terminal device comprising: The control unit requests transfer of an I picture included in video data corresponding to video broadcast from the broadcast station at a predetermined timing after the start of reception of the broadcast wave;
The mobile terminal device according to claim 1. The control unit maintains the screen display of the read I picture until reception quality is restored.
The mobile terminal device according to claim 1, wherein the mobile terminal device is a mobile terminal device. An image correction program executed by a computer having a storage unit storing an I picture,
When receiving the broadcast wave from the broadcasting station, the reception quality of the broadcast wave is monitored, and when the reception quality deterioration is detected, the reception quality is recovered from the storage unit from the timing of the frame where the reception quality deterioration is detected. The corresponding I picture is read up to the timing of the detected frame, and the read I picture is displayed on the screen.
An image correction program causing a computer to execute processing.

Images