JP2011030075A - Presentation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a presentation system capable of quickly displaying a video intended to be displayed even when a projection video display device is wirelessly connected to a PC, and having high convenience of a user. <P>SOLUTION: The presentation system includes: a projection video display device 40 for projecting video light on a projection surface; and a plurality of devices 20, 50 communicable via a radio communication network 70. In the presentation system, the apparatus includes a communication unit 60 capable of transmitting information to the radio communication network; and the communication unit changes the compression rate of information in accordance with the transmission environment of the radio communication network or the volume of information to be output to the radio communication network. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a presentation system that combines a personal computer (hereinafter referred to as a PC), a display device such as a projection video display device, and wireless transmission technology.

  In recent years, mobile terminals such as PCs and large display devices are often used in education sites. In such education sites, the contents of teaching materials transmitted from PCs are transferred to, for example, the screens of projection video display devices. Is displayed. Each student in the classroom proceeds with learning by listening to the teacher's story while watching the contents displayed on the screen.

  On the other hand, there are many classes conducted by a small number of people (several people), but a large number of students line up their desks and receive classes (for example, dozens of students lined up in a two-dimensional array). As each student also takes classes with a mobile terminal, the connection (wiring) between each student's mobile terminal and a PC or projection display becomes a problem in the classroom. it is conceivable that.

The above is an explanation of the educational site, but it is considered that the same problem occurs in business sites such as conferences.
JP 2008-233310 A

  However, when a projection display apparatus and a PC are connected wirelessly, an image to be displayed may not be displayed neatly or a time lag may occur. Specifically, communication via a wireless communication network is greatly affected by the propagation environment of the network and the amount of information.

  Therefore, the present invention has been made to solve the above-described problem, and even if the projection display apparatus and the PC are connected wirelessly, it is possible to display a desired image at a high speed, which is convenient for the user. The purpose is to provide a high presentation system.

  In order to solve the above-described problems, the present invention has the following features. First, in one aspect of the present invention, the presentation system (presentation system 10) is a projection display apparatus (projection display apparatus 40) that projects image light (image light I) onto a projection surface (screen 30). And a plurality of devices (for example, the PC 20 and the tablet 50) capable of communicating via the wireless communication network (wireless communication network 70). The device includes a communication unit (communication unit 60) capable of transmitting information to the wireless communication network, and the communication unit depends on a propagation environment of the wireless communication network or an amount of information output to the wireless communication network. The compression rate of the information is changed.

  According to this feature, each device includes a communication unit that can transmit information to the wireless communication network. The communication unit changes the compression rate of the information according to the propagation environment of the wireless communication network or the amount of information output to the wireless communication network. Therefore, if the presentation system of the present invention is introduced, the projection display apparatus and each device such as a PC are connected wirelessly, and information can be exchanged. Furthermore, even in the case of data with a large amount of information, since information can be exchanged at high speed, the convenience of the user can be improved.

  In the above one feature, the communication unit can receive information from the wireless communication network, and the device displays information on the device according to information received from the wireless communication network (control Unit 200). Thereby, in each apparatus, the information received from the wireless communication network can be displayed at high speed regardless of the size of the information.

  In the above feature, the projection display apparatus controls a communication unit capable of receiving information from the wireless communication network and an image to be projected onto the projection surface according to the information received from the wireless communication network. A control unit. Thereby, the projection display apparatus can display information from each device, particularly a PC, at high speed regardless of the size of the information.

  According to the present invention, it is possible to provide a presentation system that is highly convenient for the user by wirelessly connecting the projection display apparatus and each device such as a PC.

It is a figure which shows the structure of the presentation system which concerns on 1st Embodiment. It is a figure which shows the structure of the tablet which concerns on 1st Embodiment. It is a block diagram which shows the communication unit which concerns on 1st Embodiment. It is a flowchart which shows the compression rate change procedure which concerns on 1st Embodiment. It is a block diagram which shows the control unit which concerns on 1st Embodiment.

  Hereinafter, a presentation system according to an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[First Embodiment]
(Presentation system configuration)
The configuration of the presentation system according to the first embodiment will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a presentation system according to the first embodiment.

  As shown in FIG. 1, the presentation system 10 includes a personal computer (hereinafter referred to as a PC 20) operated by a teacher T, a projection video display device 40 that performs enlarged projection on a screen 30 that is a projection surface, and a plurality of students S1 to S3. Are operated by tablets 50-1 to 50-3. In this embodiment, an explanation is given on the premise that the teacher T operates the PC 20 and the student S operates the tablet 50, assuming, for example, an education site. The tablet 50 may be operated. Further, instead of the tablet 50, all the members may operate the PC 20, and conversely, all the members may operate the tablet 50.

  The PC 20 includes a display unit 21 that displays an image and the like, and a projection video display device 40 and an operation unit 22 that operates the PC 20. Although details will be described later, the PC 20 includes a communication unit 60 (not shown), and is connected to the wireless communication network 70 via the communication unit 60.

  The screen 30 reflects the image light from the projection display apparatus 40. The area of the image light I projected from the projection display apparatus 40 onto the screen 30 is defined as an image 31 constituted by the image light I. The screen 30 includes a projection-type image display device 40 at the top.

  The projection display apparatus 40 is provided on the upper part of the screen 30. The projection display apparatus 40 incorporates a communication unit 60 (not shown) and is connected to the wireless communication network 70 via the communication unit 60.

  The projection display apparatus 40 includes a light source that emits white light (not shown), a UV / IR cut filter that transmits visible light and blocks invisible light (external light), and a fly-eye lens unit that equalizes light. A PBS array that aligns the polarization state of light, and liquid crystal panels that modulate visible light (red component light, green component light, and blue component light) (for example, red component light liquid crystal panel, green component light liquid crystal panel, and blue light) A liquid crystal panel for component light) and a cross dichroic prism that combines light emitted from the liquid crystal panel. The projection display apparatus 40 enables projection with a very short focal length from the top of the screen 30 by a projection lens group and an aspherical concave mirror.

  As shown in FIG. 2, the tablet 50 displays images and the like, and performs a touch panel unit 51 capable of operating other devices and entering responses, and switching images displayed on the touch panel unit 51 and selecting menus. A plurality of operation buttons 52, 53, and 54 and an operation pen 55 for performing an input operation to the touch panel unit 51 are provided. The tablet 50 includes a communication unit 60 (not shown) and is connected to the wireless communication network 70 via the communication unit 60.

(Configuration of wireless communication network)
Next, a wireless communication network (for example, a wireless LAN such as IEEE 802.11n) 70 according to the first embodiment will be described with reference to the drawings. In the present embodiment, information is exchanged between the devices (PC 20, projection display device 40, and tablet 50) via communication unit 60 and wireless communication network 70. In the following, description will be made on the premise of transmission of moving image data that seems to be the most burdensome on the wireless communication network 60.

  In general, when data is transmitted through the wireless communication network 70, the transmission rate varies depending on the propagation environment, and therefore, a predetermined amount of data may not be transmitted within a predetermined period. Therefore, in the communication unit 60, it is confirmed whether or not encoded data for one frame has been transmitted within the frame period. If the encoded data cannot be transmitted, the communication unit 60 performs setting to increase the compression rate of the compression code. Thereby, it becomes possible to perform the compression encoding process of a moving image with the compression rate suitable for a propagation environment, and a moving image with high real-time property can be transmitted reliably.

  Here, the “frame” is a screen unit for each frame constituting the moving image data, and the Motion JPEG compression method performs an intra-frame compression process in this screen unit. In interlaced moving image data such as NTSC (National Television Standards Committee), a field corresponds. A non-interlaced moving image data such as a VGA (Video Graphics Array) corresponds to a frame.

  The “frame period” refers to a time interval between frames arranged on the time axis. In the case of the above-mentioned NTSC, it is about 16.6 ms, and in the case of VGA, it is about 33.3 ms.

  FIG. 3 is a conceptual diagram showing the configuration of the communication unit 60 according to Embodiment 1 of the present invention. The communication unit 60 includes a transmission unit 100, a compression unit 101, a recording unit 102, a control unit 103, a reception unit 104, and a decompression unit 105.

  In FIG. 3, the transmission unit 100 is connected to the wireless communication network 70, converts information to be transmitted into the data format of the wireless communication network 70, and outputs the data to the wireless communication network 70. In addition, a transmission buffer for buffering the output from the compression unit 101 is included to adjust the transmission timing.

  When the encoded data output from the compression unit 101 reaches a predetermined transmission unit (for example, 1500 bytes), the transmission unit 100 reads out the encoded data from the transmission buffer, converts the data format, and performs the wireless communication network 70. Send to.

  The compression unit 101 performs compression coding processing using the Motion JPEG compression method on moving image data input from the outside. The Motion JPEG compression method applies a JPEG compression method, which is a still image compression method, to a moving image, and performs JPEG compression processing for each frame of moving image data.

  The compression unit 101 performs processing such as Discrete Cosine Transform (DCT), quantization, Huffman coding, and the like, and then includes the compression rate and identification information indicating whether the method is a sequential method or a progressive method. The header information is added to the moving image data that has been subjected to compression processing, and encoded data of the Motion JPEG compression method is generated. Each time encoded data in a predetermined output unit (for example, macroblock unit or wireless packet payload length unit) is generated, the encoded data is output to the transmission unit 100.

  The compression unit 101 changes the compression rate in the compression process according to setting parameters included in a configuration file described later. For example, the compression rate is changed by changing the quantization step.

  The recording unit 102 records a configuration file that includes setting parameters for changing the compression rate of the compression unit 101. Note that it is preferable to prepare a plurality of configuration files so that a wide range of compression rates can be set from a setting with a low compression rate (ie, high-quality compression) to a setting with a high compression rate (ie, low-quality compression).

  The control unit 103 controls the timing of the entire communication unit 60 and the like. Further, the control unit 103 initializes the timing counter at the frame start timing of the moving image data, for example, at the rising edge of the vertical synchronization signal (Vsync: 1195125407546_0) of the moving image data. When it is determined from the timing counter value that one frame period has elapsed from the frame start timing of the moving image data, that is, the frame end timing has been reached, the control unit 103 checks the remaining amount of encoded data in the transmission buffer. To do.

  If a sufficient transmission rate cannot be ensured, compression encoding processing of the frame to be processed is performed within one frame period from the frame start timing of the moving image data, and the encoded data of the compression encoded frame cannot be transmitted. Sometimes.

  If the state in which the encoded data of the frame to be processed cannot be transmitted within one frame period continues, overflow occurs in the transmission buffer, and moving image data cannot be transmitted in real time.

  Therefore, the control unit 103 determines whether the encoded data of the frame to be processed can be transmitted within one frame period from the frame start timing of the moving image data input from an imaging device (for example, a camera) (not shown). Judgment is made based on the remaining amount of the transmission buffer.

  When the remaining amount of encoded data is confirmed (that is, when encoded data for one frame cannot be transmitted within the frame period), it is determined that the compression rate in the compression unit 101 is too low for the transmission rate. Then, the control unit 103 increases the compression rate of the compression unit 101. Therefore, the control unit 103 reads a configuration file that sets a compression rate higher than the current compression rate from the recording unit 102, and sets the compression rate of the compression unit 101 high based on the setting parameters included in the configuration file. When the compression rate is set high, the compression rate may be set one step higher than the current compression rate or may be set to the highest compression rate.

  When the compression rate is set higher by one step, transmission of moving image data suitable for the propagation environment can be realized while suppressing deterioration of the quality of the encoded data. When the highest compression rate is set, frequent changes in the compression rate are suppressed, and moving image data can be transmitted robustly.

  When the encoded data is generated by the compression unit 101, it is preferable to increase the amount of encoded data if high quality moving image data is to be transmitted. However, if the amount of encoded data is increased too much, it may be sufficient depending on the propagation environment. Since a high transmission rate cannot be ensured, the compression rate is frequently changed, making it difficult to transmit moving image data robustly.

  Therefore, since the control unit 103 robustly transmits high-quality moving image data, when the remaining amount of the encoded data is not confirmed (that is, the encoded data for one frame can be transmitted within the frame period). ), The compression rate is set so that the encoded data amount falls within a predetermined range.

  The control unit 103 stores a threshold value related to the upper limit of the encoded data amount (hereinafter referred to as the first threshold value) and a threshold value related to the lower limit of the encoded data amount (hereinafter referred to as the second threshold value). ing. Here, the first threshold value is larger than the second threshold value. For example, when the first threshold value is 48 Kbytes, the second threshold value is 40 Kbytes. These threshold values are obtained by experiments (for example, changing the compression rate for various moving image data and subjectively evaluating the image quality of the generated encoded data). Further, these threshold values may be different for each moving image data system (for example, the above-mentioned NTSC or VGA).

  The control unit 103 measures the data amount when storing the encoded data for one frame generated by the compression unit 101 in the transmission buffer of the transmission unit 100.

  When the encoded data for one frame is transmitted within the frame period, the control unit 103 compares the measured data amount with the first threshold value. If the measured data amount is larger than the first threshold value, it is determined that the current compression rate is too low, and the control unit 103 increases the compression rate of the compression unit 101. The setting for increasing the compression rate of the compression unit 101 is performed in the same manner as the setting of the compression rate when the encoded data for one frame cannot be transmitted within the frame period.

  In addition, when the encoded data for one frame is transmitted within the frame period, the control unit 103 compares the measured data amount with the second threshold value. If the measured data amount is smaller than the second threshold value, it is determined that the current compression rate is too high, and the control unit 103 lowers the compression rate of the compression unit 101. Therefore, the control unit 103 reads a configuration file that sets a compression rate lower than the current compression rate from the recording unit 102, and sets the compression rate of the compression unit 101 to be low based on the setting parameter included in the configuration file. When setting the compression rate low, the compression rate may be set one step lower than the current compression rate, or may be set to the lowest compression rate.

  When the compression rate is set to one step lower, it is possible to realize transmission of moving image data suitable for the propagation environment while suppressing deterioration of the quality of the encoded data. When the minimum compression rate is set, high-quality moving image data can be transmitted.

  The timing for changing the compression rate may be the timing at which the compression unit 101 generates encoded data for one frame, that is, the frame period, and the control unit 103 encodes encoded data for one frame within the frame period. May be performed at a timing at which it is determined that cannot be transmitted. If the compression rate is changed at the frame period, the burden on the compression encoding process is reduced. If the compression rate is changed at the timing when the control unit 103 determines that transmission is not possible, the followability of the compression encoding process with respect to a change in transmission speed is improved, so that transmission of moving image data more suitable for the propagation environment can be realized.

  FIG. 4 is a flowchart showing the compression rate changing procedure. The control unit 103 detects the remaining amount of the transmission buffer of the transmission unit 100 and confirms whether or not encoded data for one frame has been transmitted within the frame period (S100). When the encoded data for one frame has been transmitted (Y in S100), the control unit 103 confirms whether the amount of encoded data for one frame is equal to or greater than the first threshold (S101).

  When the amount of encoded data for one frame is smaller than the first threshold (N in S101), the control unit 103 determines whether the amount of encoded data for one frame is equal to or smaller than the second threshold. Confirm (S102). When the amount of encoded data for one frame is equal to or smaller than the second threshold (Y in S102), the control unit 103 checks whether or not the compression rate of the compression unit 101 is the lowest compression rate. (S103). When the compression rate is not the lowest (N in S103), the control unit 103 reads the corresponding configuration file from the recording unit 102, and executes the setting for reducing the compression rate of the compression unit 101 based on the configuration file. The process is terminated (S104).

  When the encoded data for one frame cannot be transmitted (N in S100) or the encoded data amount for one frame is greater than or equal to the first threshold (Y in S101), the control unit 103 It is confirmed whether or not the compression rate of the compression unit 101 is the highest compression rate (S105).

  When the compression rate is not the highest (N in S105), the control unit 103 reads the corresponding configuration file from the recording unit 102, and executes the setting for increasing the compression rate of the compression unit 101 based on the configuration file. The process is terminated (S106). When the amount of encoded data for one frame is not less than or equal to the second threshold (N in S102), the compression rate is the lowest (Y in S103), or the compression rate is the highest (Y in S105) ), The process is terminated.

  According to such a configuration, the compression rate of the compression unit 101 is set to be high if it is equal to or greater than the first threshold value, and the compression rate of the compression unit 101 is decreased if it is equal to or less than the second threshold value. Set up. For this reason, it is possible to perform compression encoding processing of a moving image at a compression rate suitable for the propagation environment, and it is possible to transmit a moving image in real time with robustness and high quality.

  Returning to FIG. 3, reception of information from the wireless communication network 70 will be described. First, the receiving unit 104 is connected to the wireless communication network 70 and receives information to be input from the wireless communication network 70. When the information received from the wireless communication network 70 reaches a predetermined input unit, the receiving unit 104 outputs the information to the decompressing unit 105.

  The decompression unit 105 performs decompression processing on the encoded data input from the reception unit 104. The decompressing unit 105 outputs the decompressed moving image data to each device (the PC 20, the projection display apparatus 40, and the tablet 50) for each predetermined input unit.

  These configurations can be realized in terms of hardware by a CPU, memory, or other LSI of an arbitrary computer, and in terms of software, they are realized by programs loaded into the memory. Draw functional blocks. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

(Configuration of control unit)
Next, the configuration of the control unit according to the first embodiment will be described with reference to the drawings. FIG. 5 is a block diagram showing the control unit according to the first embodiment.

  As shown in FIG. 5, the control unit 200 is provided in each device (PC 20, projection video display device 40, and tablet 50). Here, for example, a case provided in the PC 20 will be described. Specifically, the control unit 200 includes an information selection unit 201, a basic video generation unit 202, and a video control unit 203.

  The information selection unit 201 selects necessary information from the information output from the communication unit 60 or video information (video input signal) input from the outside according to, for example, a user instruction. Information selected by the information selection unit 201 is output to the basic image generation unit 202. When the display instruction signal to the tablet 50 is attached together with the moving image data output from the PC 20, the information selection unit 201 of the tablet 50 gives priority to the display instruction signal over the user instruction, and the moving image output from the PC 20 Image data is output to the basic image generation unit 202.

  The basic video generation unit 202 generates a basic video based on the information output from the information selection unit 201 or the video input signal input from the outside. Specifically, the basic video generation unit 202 configures a video displayed on the display unit 21 by the PC 20, a video projected by the projection video display device 40 on the screen 30, and a video displayed by the tablet 50 on the touch panel 51. To generate a basic video.

  The video control unit 203 controls a display unit mounted on each device, specifically, a liquid crystal panel or the like, according to the video signal output from the basic video generation unit 202.

  With the above configuration, the information that each student S describes on the tablet 50 can be projected onto the screen 30 from the projection display apparatus 40 onto the screen 30. Here, the control unit 200 has been described as being provided in the PC 20, but is not limited thereto. For example, the control unit 200 may be provided in the projection display device 40, and may be provided in each tablet 50. It may be provided.

(Action / Effect)
In the first embodiment, the communication unit 60 switches the compression rate and the transmission rate according to the propagation environment and the amount of information. The control unit 200 selects input information from the wireless communication network 70. As a result, it becomes possible to perform compression encoding processing of information (particularly moving image data) at a compression rate suitable for the propagation environment, and information with high real-time characteristics can be transmitted reliably. In addition, wiring in the classroom is not necessary, and the degree of freedom of arrangement of each device is increased. In addition, each student's answers, works, opinions, etc. can be easily displayed on the screen, enabling active classes.

[Other Embodiments]
Although the present invention has been described with reference to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  Specifically, the projection display apparatus 40 may be provided with an imaging device that captures a projection image on the screen 30. Thereby, the content of the lesson can be imaged, and the moving image data of the lesson can be transmitted at high speed to the students at a remote location via the wireless communication network 70 of the present invention.

  Further, the tablet 50 may include an imaging device. As a result, in addition to the contents described on the touch panel 51, it is possible to visualize and present what each student has observed and the created work. Of course, an imaging device may be connected to the PC 20, and the imaging device itself may include a communication unit. For the tablet 50, the presentation system of the present invention will be more realizable by using a game device including a touch panel, operation buttons, a touch pen, and an imaging device.

  Furthermore, the tablet 50 may be provided with a data storage means and may serve as a means for contacting each home from the school side. In addition to being able to achieve paperlessness, analysis of the transition of each student's grades and the like can be facilitated if gradebooks are distributed to each home via the tablet 50.

  In addition to the devices described in the embodiments, a data storage device such as iVDR may be connected to the wireless communication network 70. Class contents and videos taken by each student can be digital archived.

  From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  DESCRIPTION OF SYMBOLS 10 ... Presentation system, 20 ... PC, 21 ... Display part, 22 ... Operation part, 30 ... Screen, 31 ... In image, 40 ... Projection type image display apparatus, 50 ... Tablet, 51 ... Touch panel, 52-54 ... Operation button 55 ... Touch pen, 60 ... Communication unit, 70 ... Wireless communication network, 100 ... Transmission unit, 101 ... Compression unit, 102 ... Recording unit, 103 ... Control unit, 104 ... Reception unit, 105 ... Decompression unit, 200 ... Control unit 201 ... Information selection unit 202 ... Basic video generation unit 203 ... Video control unit

Claims (3)

A presentation system comprising a projection display device for projecting image light onto a projection surface and a plurality of devices capable of communicating via a wireless communication network,
The device includes a communication unit capable of transmitting information to the wireless communication network,
The said communication part changes the compression rate of the said information according to the propagation environment of the said wireless communication network, or the quantity of the information output to the said wireless communication network, The presentation system characterized by the above-mentioned. The presentation system according to claim 1, wherein
The communication unit is capable of receiving information from the wireless communication network;
The presentation system includes a control unit that displays information on the device according to information received from the wireless communication network. The presentation system according to claim 1, wherein
The projection display apparatus is
A communication unit capable of receiving information from the wireless communication network;
A presentation system comprising: a control unit that controls an image projected onto the projection surface in accordance with information received from the wireless communication network.