JP2016014834A - Image processing apparatus, image processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent flicker and fluctuation of a display image to the maximum extent.SOLUTION: An image processing apparatus includes: a video acquisition part 21 that acquires a video signal and creates a sampling clock signal on the basis of the video signal; an image processing part 30 that calculates the amount of change in brightness between two frames of the video signal; and a phase adjustment control part 29 that determines the phase of the sampling clock signal on the basis of the amount of change in brightness and outputs the phase from the video acquisition part 21. The phase adjustment control part 29 determines the phase of the sampling clock signal in which the amount of change in brightness becomes maximum and causes the video acquisition part 21 to create a sampling clock signal with a reverse phase having a phase reverse to the determined phase.

Description

  The present invention relates to an image processing apparatus, an image processing method, and a program suitable for preventing the flicker and fluctuation of a display image that occur when a video signal acquired from outside is displayed.

  2. Description of the Related Art Conventionally, an electronic blackboard that allows a background image from a computer device to be displayed on a display and a user to draw stroke images such as letters, numbers, and figures on the background image at a meeting in a company, an educational institution, an administrative organization, etc. Is being used.

Here, the contents of the analog video signal output from the computer apparatus and the display image generation method performed by a general receiving apparatus will be described.
The analog video signal output from the computer apparatus is mainly composed of a signal (hereinafter referred to as RGB signal) representing luminance of R (red), G (green), and B (blue), a horizontal synchronization signal, a vertical synchronization signal, and the like. ing. This RGB signal is configured so that the luminance of each pixel is represented by a voltage value when the image area is scanned by the horizontal synchronizing signal and the vertical synchronizing signal. In an apparatus that receives an analog video signal, the voltage value representing the luminance of each pixel is analog / digital converted by an A / D converter by sampling the voltage value of the RGB signal, and the image data converted into digital data is converted into digital data. Is generated.
Here, since the sampling clock signal used for sampling in the A / D converter is generated by the PLL circuit inside the receiving device, the phase of the sampling clock signal is shifted from the RGB signal. For this reason, it is necessary to adjust the phase of the sampling clock signal.

  In Patent Document 1, the display area is divided into a plurality of areas, the amount of change in luminance value between pixels and the previous frame is calculated for each area, the luminance difference between pixels is weighted, and the previous frame A technique of setting a sampling clock phase at which a difference value between luminance values becomes small is disclosed.

However, in Patent Document 1, when the luminance difference between the pixels is uniformly small in each divided area when the phase adjustment is performed, the optimum phase cannot be determined. In addition, since the phase adjustment is not performed at regular intervals, the optimum phase cannot be determined at the timing when the luminance difference between pixels becomes large. Furthermore, there is a problem that even if the number of phase adjustments is repeated, a more appropriate phase cannot be determined.
The present invention has been made in view of the above, and an object thereof is to provide an image processing apparatus, an image processing method, and a program that can prevent flickering and fluctuation of a display image to the maximum extent.

  In order to solve the above problems, the invention according to claim 1 acquires a video signal and generates a sampling clock signal based on the video signal, and a luminance change between two frames of the video signal An image processing unit that calculates an amount; and a phase adjustment control unit that determines a phase of the sampling clock signal based on the luminance change amount and outputs the phase from the video acquisition unit, and the phase adjustment control The unit obtains a phase of the sampling clock signal that maximizes the amount of change in luminance, and causes the video acquisition unit to generate a sampling clock signal having an inverted phase obtained by inverting the phase.

  According to the present invention, the phase of the sampling clock signal that maximizes the amount of change in luminance between two frames of the video signal is obtained, and the video acquisition unit generates a sampling clock signal having an inverted phase obtained by inverting the phase. The flickering and fluctuation of the display image can be prevented to the maximum.

1 is an overall configuration diagram of an image processing system according to an embodiment. It is a hardware block diagram of an electronic blackboard. It is a functional block diagram of an electronic blackboard. It is a functional block diagram of a file processing unit. It is a conceptual diagram which shows page data. It is a conceptual diagram which shows stroke data. It is a conceptual diagram which shows coordinate arrangement | sequence data. It is a conceptual diagram which shows media data. It is a conceptual diagram which shows an address book management table. It is a conceptual diagram which shows backup data. It is a conceptual diagram which shows operation data. It is a block diagram of each image layer. 1 is a block diagram illustrating a characteristic configuration of an image processing apparatus according to an embodiment of the present invention. It is a flowchart which shows the main operation | movement of the phase adjustment control part shown in FIG. It is a flowchart which shows operation | movement of the subroutine of the phase adjustment control part shown in FIG. It is a timing chart which shows an example in which the phase of a sampling clock signal is appropriate with respect to the phase of an RGB signal. It is a timing chart which shows an example in which the phase of a sampling clock signal is inappropriate with respect to the phase of RGB signal.

  An embodiment of the present invention will be described. The present invention calculates the amount of change in luminance between two frames in all pixels in the display area for each phase of the sampling clock signal. Then, the phase of the sampling clock signal that maximizes the amount of change in luminance between two frames is extracted, and the inverted phase of this phase is set as the phase in the sampling clock signal. At this time, the phase at which the luminance change amount is maximized is stored, and this phase adjustment flow is performed at regular intervals. The maximum luminance change amount in the phase adjustment flow is the luminance change amount at the previous phase adjustment. If it is larger than the maximum value, the phase setting is updated. Otherwise, the phase setting is not updated.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
<System overview>
FIG. 1 is an overall configuration diagram of an image processing system according to the present embodiment. In FIG. 1, only two electronic blackboards 2a and 2b and electronic pens 4a and 4b associated with the electronic blackboards 2a and 2b are shown to simplify the description. A pen or the like may be used.
As shown in FIG. 1, the image processing system 1 includes a plurality of electronic blackboards 2a and 2b, a plurality of electronic pens 4a and 4b, USB memories 5a and 5b, notebook PCs (Personal Computer) 6a and 6b, a television ( Video) having conference terminals 7a, 7b and PC8. The electronic blackboards 2a and 2b and the PC 8 are connected via a communication network 9 so that they can communicate with each other. Further, the plurality of electronic blackboards 2a and 2b are respectively provided with displays 3a and 3b. Also, the electronic blackboard 2a has an event generated by the electronic pen 4a (the pen tip of the electronic pen 4a on the display 3a or An image drawn by touching the pen butt of the electronic pen 4a can be displayed on the display 3a. Note that the image displayed on the display 3a can be changed based not only on the electronic pen 4a but also on an event (a gesture such as enlargement, reduction, or page turning) generated by the user's hand Ha or the like.

The electronic blackboard 2a can be connected to a USB memory 5a. The electronic blackboard 2a reads an electronic file such as PDF from the USB memory 5a, and the electronic blackboard 2a records an electronic file in the USB memory 5a. Can do. The electronic blackboard 2a is connected to a display port, a DVI (Digital Visual Interface), an HDMI (registered trademark) (High-Definition Multimedia Interface), and a cable 10a1 capable of communication according to a standard such as VGA (Video Graphics Array). A notebook PC 6a is connected. Then, the electronic blackboard 2a generates an event by touching the display 3a, and transmits event information indicating the event to the notebook PC 6a in the same manner as an event from an input device such as a mouse or a keyboard. Similarly, a television (video) conference terminal 7a is connected to the electronic blackboard 2a via a cable 10a2 capable of communication according to the above-mentioned standards. Note that the notebook PC 6a and the video conference terminal 7a may communicate with the electronic blackboard 2a by wireless communication complying with various wireless communication protocols such as Bluetooth (registered trademark).
On the other hand, in the other bases where the electronic blackboard 2b is installed, the electronic blackboard 2b with the display 3b, the electronic pen 4b, the USB memory 5b, the notebook PC 6b, the video conference terminal 7b, the cable 10b1, and the cable 10b2 in the same manner as described above. Is used. Furthermore, the image displayed on the display 3b can be changed based on an event caused by the user's hand Hb or the like.

Thereby, the image drawn on the display 3a of the electronic blackboard 2a at one base is also displayed on the display 3b of the electronic blackboard 2b at another base, and conversely on the display 3b of the electronic blackboard 2b at another base. The image drawn on is displayed on the display 3a of the electronic blackboard 2a at one base. As described above, the image processing system 1 can perform remote sharing processing for sharing the same image at a remote location, and thus is very convenient when used for a conference or the like at a remote location.
In the following, when an arbitrary electronic blackboard among the plurality of electronic blackboards is indicated, it is indicated as “electronic blackboard 2”. When an arbitrary display among a plurality of displays is shown, “display 3” is shown. When an arbitrary electronic pen among a plurality of electronic pens is indicated, it is indicated as “electronic pen 4”. When an arbitrary USB memory is indicated among the plurality of USB memories, it is indicated as “USB memory 5”. When an arbitrary notebook PC is indicated among the plurality of notebook PCs, it is indicated as “node PC 6”. When an arbitrary video conference terminal is indicated among the plurality of video conference terminals, it is indicated as “video conference terminal 7”. In addition, “hand H” is used when an arbitrary hand among the hands of a plurality of users is shown. When an arbitrary cable is indicated among the plurality of cables, it is indicated as “cable 10”.

In this embodiment, an electronic blackboard will be described as an example of an image processing apparatus. However, the present invention is not limited to this, and the present invention can also be applied to products such as a projector and a display as other examples of the image processing apparatus. The notebook PC 6 will be described as an example of the information processing terminal, but is not limited thereto. Other examples of the information processing terminal include a desktop PC, a tablet PC, a PDA, a digital video camera, a digital camera, and a game. It may be a terminal capable of supplying image frames such as a machine.
Further, the communication network includes the Internet, a LAN (Local Area Network), a mobile phone communication network, and the like. In this embodiment, a USB memory is described as an example of a recording medium. However, the present invention is not limited to this, and various recording media such as an SD card may be used as another example of the recording medium.

<Hardware configuration of electronic blackboard>
Next, the hardware configuration of the electronic blackboard according to the present embodiment will be described with reference to FIG. FIG. 2 is a hardware configuration diagram of the electronic blackboard.
As shown in FIG. 2, the electronic blackboard 2 includes a CPU 101 that controls the operation of the electronic blackboard 2 as a whole, a ROM 102 that stores a program used to drive the CPU 101 such as an IPL, and a RAM 103 that is used as a work area of the CPU 101. And an SSD 204 for storing various data such as a program for the electronic blackboard 2, a network controller 105 for controlling communication with the communication network 9, and an external storage controller 106 for controlling communication with the USB memory 5.
The electronic blackboard 2 includes a capture device 111 that acquires video information displayed on the display of the notebook PC 6 as a still image or a moving image, a GPU (Graphics Processing Unit) 112 that specializes in graphics, and an output image from the GPU. Is output to the display 3 or the video conference terminal 7, a display controller 105 that controls and manages screen display is provided.

  The electronic blackboard 2 further includes a sensor controller 114 that controls processing of the contact sensor 115 and a contact sensor 115 that detects that the electronic pen 4 or the hand H of the user touches the display 3. The contact sensor 115 performs coordinate input and coordinate detection by an infrared ray blocking method. In this coordinate input and coordinate detection method, two light emitting / receiving devices (not shown) installed at both upper ends of the display 3 emit a plurality of infrared rays in parallel with the display 3, This is a method of receiving light that is reflected by the reflecting member provided on the light source and returns on the same optical path as the light path of the light emitted by the light receiving element. The contact sensor 115 outputs infrared IDs (Identification) emitted from the two light receiving and emitting devices blocked by the object to the sensor controller 114, and the sensor controller 114 specifies the coordinate position that is the contact position of the object. All IDs shown below are examples of identification information.

In addition, the contact sensor 115 is not limited to the infrared ray blocking method, but a capacitance type touch panel that identifies a contact position by detecting a change in capacitance, or a contact position determined by a voltage change of two opposing resistance films. Various detection means such as a resistance film type touch panel to be identified and an electromagnetic induction type touch panel to identify a contact position by detecting electromagnetic induction caused by contact of a contact object with the display unit may be used.
The electronic blackboard 2 includes an electronic pen controller 116. This electronic pen controller 116 communicates with the electronic pen 4 to determine whether or not there is a pen tip touch or a pen butt touch on the display 3. It should be noted that the electronic pen controller 116 may determine whether or not the user grips the part of the electronic pen 4 as well as the other electronic pen part, as well as the pen tip and the bottom of the electronic pen 4.
Further, the electronic blackboard 2 includes the CPU 101, ROM 102, RAM 103, SSD 104, network controller 105, external storage controller 106, capture device 111, GPU 112, sensor controller 114, and electronic pen controller 116 as shown in FIG. A bus line 120 such as an address bus or a data bus for electrical connection is provided.
The program for the electronic blackboard 2 may be recorded and distributed on a computer-readable recording medium such as a CD-ROM.

<Functional configuration of electronic blackboard>
Next, the functional configuration of the electronic blackboard will be described with reference to FIGS. First, the overall functional configuration of the electronic blackboard 2 will be described with reference to FIG. FIG. 3 is a functional block diagram of the electronic blackboard.
The electronic blackboard 2 has the functional configurations shown in FIG. 3 by the hardware configuration and program shown in FIG. The electronic blackboard 2 can be a “host device” that starts the remote sharing process first, and can also be a “participating device” that participates in the remote sharing process that has already started. The electronic blackboard 2 is roughly composed of both the client unit 20 and the server unit 90. The client unit 20 and the server unit 90 are functions realized in one housing of the electronic blackboard 2. When the electronic blackboard 2 is a hosting device, the electronic blackboard 2 implements the client unit 20 and the server unit 90. Further, when the electronic blackboard 2 is a participating device, in the electronic blackboard 2, the client unit 20 is realized, but the server unit 90 is not realized. That is, in FIG. 1, when the electronic blackboard 2a is the hosting device and the electronic blackboard 2b is the participating device, the client unit 20 of the electronic blackboard 2a receives the other via the server unit 90 realized in the same electronic blackboard 2a. Communicate with the client unit 20 of the electronic blackboard 2b. On the other hand, the client unit 20 of the electronic blackboard 2b communicates with the client units of the other electronic blackboard 2a via the server unit 90 realized in the other electronic blackboard 2a.

<Functional configuration of client unit 20>
Next, the functional configuration of the client unit 20 will be described mainly using FIGS. 3 to 4. The client unit 20 includes a video acquisition unit 21, a coordinate detection unit 22, an automatic adjustment unit 23, a contact detection unit 24, an event distribution unit 25, an operation processing unit 26, a gesture processing unit 27, a video superimposition unit 28, and a phase adjustment control unit. 29, an image processing unit 30, and a communication control unit 60.
Among these, the video acquisition unit 21 acquires the output video of the video output device connected to the cable 10. When the video acquisition unit 21 receives an image signal from the video output device, the video acquisition unit 21 analyzes the image signal, and updates the resolution of the image frame that is a display image of the video output device formed by the image signal. Image information such as frequency is derived and output to the image acquisition unit 31.
The coordinate detection unit 22 detects the coordinate position of an event (such as an operation in which the user's hand H is touched on the display 3) generated by the user on the display 3. The coordinate detection unit 22 also detects the touched area.
The automatic adjustment unit 23 is activated when the electronic blackboard 2 is activated, and adjusts the image processing parameters of the sensor camera in the optical sensor method of the contact sensor 115 so that the contact sensor 115 can output an appropriate value to the coordinate detection unit 22. To do.

The contact detection unit 24 detects an event (such as an operation in which the pen tip of the electronic pen 4 or the pen tip of the electronic pen 3 is pressed (touched) on the display 3).
The event distribution unit 25 distributes the coordinate position of the event detected by the coordinate detection unit 22 and the detection result detected by the contact detection unit 24 to each event of stroke drawing, UI operation, and gesture operation.
Here, “stroke drawing” is performed when the user presses the electronic pen 4 on the display 3 when a stroke image (B) described later shown in FIG. 12 is displayed on the display 3. In this state, the electronic pen 4 is moved and finally the electronic pen 4 is released from the display 3. By this stroke drawing, for example, alphabets “S” and “T” are drawn on the display 3. The “stroke drawing” includes not only drawing an image but also an event of deleting an already drawn image or editing a drawn image.

The “UI operation” is an event in which the user presses a predetermined position with the electronic pen 4 or the hand H when a UI image (A) (described later) shown in FIG. . By this UI operation, for example, the color or width of a line drawn by the electronic pen 4 is set.
The “gesture operation” is an event in which the user touches or moves the display 3 with the hand H when a stroke image (B) described later shown in FIG. is there. By this gesture operation, for example, by moving the hand H while the user touches the display 3 with the hand H, the image can be enlarged (or reduced), the display area can be changed, or the page can be switched. it can.

The operation processing unit 26 executes various operations according to the UI element in which the event is generated, from what is determined as the UI operation by the event distribution unit 25. Examples of the UI element include a button, a list, a check box, and a text box.
The gesture processing unit 27 performs an operation corresponding to what is determined as a gesture operation by the event distribution unit 25.
The video superimposing unit 28 displays an image superimposed by a display superimposing unit 36 (to be described later) on the video output device (display 3 or the like) as a video. In addition, the video superimposing unit 28 performs picture-in-picture of the video sent from another video output device (such as the video conference terminal 7) with respect to the video from the video output device (such as the notebook PC 6). Further, the video superimposing unit 28 performs switching for displaying the video that is picture-in-picture and displayed on a part of the display 3 on the entire display 3.

The phase adjustment control unit 29 determines the phase of the sampling clock signal based on the luminance change amount, and causes the video acquisition unit 21 to output the phase.
The image processing unit 30 performs superimposing processing of each image layer as shown in FIG. The image processing unit 30 includes an image acquisition unit 31, a stroke processing unit 32, a UI image generation unit 33, a background generation unit 34, a layout management unit 35, a display superimposition unit 36, a page processing unit 37, a file processing unit 40, page data. A storage unit 300 and a remote license management table 310 are provided.
Among these, the image acquisition unit 31 acquires each frame as an image from the video acquired by the video acquisition unit 21. The image acquisition unit 31 outputs the image data to the page processing unit 37. This image corresponds to the output image (C) from the video output device (notebook PC 6 or the like) shown in FIG.
The stroke processing unit 32 draws an image, deletes the drawn image, or edits the drawn image based on the event related to the stroke drawing assigned by the event distribution unit 25. The image by the stroke drawing corresponds to the stroke image (B) shown in FIG. In addition, the results of drawing, deleting, and editing an image based on the stroke drawing are stored in the operation data storage unit 840 as operation data described later.

The UI image generation unit 33 generates a UI (user interface) image set in advance on the electronic blackboard 2. This UI image corresponds to the UI image (A) shown in FIG.
The background generation unit 34 receives media data from the page data read from the page data storage unit 300 by the page processing unit 37 from the page processing unit 37. The background generation unit 34 outputs the received media data to the display superimposing unit 36. The image based on the media data corresponds to the background image (D) shown in FIG. The pattern of the background image (D) is plain or grid display.
The layout management unit 35 provides layout information indicating the layout of each image output from the image acquisition unit 31, the stroke processing unit 32, and the UI image generation unit 33 (or the background generation unit 34) to the display superimposing unit 36. I manage. Thereby, the layout management unit 35 causes the display superimposing unit 36 to display the output image (C) and the stroke image (B) in the UI image (A) and the background image (D). It is possible to instruct whether to hide.
Based on the layout information output from the layout management unit 35, the display superimposing unit 36 displays the layout of each image output from the image acquisition unit 31, the stroke processing unit 32, and the UI image generation unit 33 (background generation unit 34). Do.

The page processing unit 37 stores the data of the stroke image (B) and the data of the output image (C) in one page data and stores them in the page data storage unit 300. The data of the stroke image (B) forms part of page data as the stroke arrangement data (each stroke data) indicated by the stroke arrangement data ID shown in FIG. The data of the output image (C) forms part of the page data as the media data indicated by the media data ID shown in FIG. Then, when this media data is read from the page data storage unit 300, it is handled as data of the background image (D).
Further, the page processing unit 37 transmits the media data of the once stored page data to the display superimposing unit 36 via the background generating unit 34 so that the video superimposing unit 28 displays the background image (D). 3 can be displayed again. The page processing unit 37 can return the stroke arrangement data (each stroke data) in the page data to the stroke processing unit 32 so that the stroke can be re-edited.

Further, the page processing unit 37 can delete or duplicate page data.
That is, the data of the output image (C) displayed on the display 3 when the page processing unit 37 stores the page data in the page data storage unit 300 is temporarily stored in the page data storage unit 300 and then When read from the page data storage unit 300, it is read as media data indicating the background image (D). Then, the page processing unit 37 outputs stroke arrangement data indicating the stroke image (B) among the page data read from the page data storage unit 300 to the stroke processing unit 32. Further, the page processing unit 37 outputs media data indicating the background image (D) among the page data read from the page data storage unit 300 to the background generation unit 34.

The display superimposing unit 36 includes an output image (C) from the image acquisition unit 31, a stroke image (B) from the stroke processing unit 32, a UI image (A) from the UI image generation unit 33, and a background generation unit 34. The background image (D) is superimposed according to the layout designated by the layout management unit 35. Thus, as shown in FIG. 12, each of the UI image (A), the stroke image (B), the output image (C), and the background image (D) in the order in which the user can see each image even if they overlap. It has Leia composition.
Moreover, the display superimposing unit 36 can also superimpose the image (A) and the image (B) exclusively by switching the image (C) and the image (D) shown in FIG. . For example, when the cable 10 between the electronic blackboard 2 and the video output device (notebook PC 6 or the like) is disconnected while the image (A), the image (B), and the image (C) are initially displayed. As specified by the layout management unit 35, the image (C) can be removed from the superimposition target and the image (D) can be displayed. In this case, the display superimposing unit 36 also performs display enlargement, display reduction, and display area movement processing.

The page data storage unit 300 stores page data as shown in FIG. FIG. 5 is a conceptual diagram showing page data. The page data is data for one page displayed on the display 3 (stroke arrangement data (each stroke data) and media data). Since there are many types of parameters included in the page data, the contents of the page data will be described here with reference to FIGS.
As shown in FIG. 5, the page data includes a page data ID for identifying an arbitrary page, a disclosure time indicating the start time of display of this page, rewriting of the contents of the page by a stroke, a gesture, and the like. Are associated with the end time indicating the time when the operation is stopped, the stroke arrangement data ID for identifying the stroke arrangement data generated by the stroke of the electronic pen 4 or the user's hand H, and the media data ID for identifying the media data. Is remembered. The stroke arrangement data is data for displaying a stroke image (B) shown in FIG. The media data is data for displaying a background image (D) shown in 16 described later on the display 3.

With such page data, for example, when the user draws the alphabet “S” with the electronic pen 4, the stroke is written in one stroke, and therefore, one stroke data ID is displayed and one letter of the alphabet [S] is indicated. However, when the user draws the alphabet “T” with the electronic pen 4, since it is a two-stroke writing, the one letter “T” is indicated by two stroke data IDs.
The stroke arrangement data shows detailed information as shown in FIG. FIG. 6 is a conceptual diagram showing stroke arrangement data. As shown in FIG. 6, one stroke arrangement data is represented by a plurality of stroke data. One stroke data includes a stroke data ID for identifying the stroke data, a start time indicating the start time of writing one stroke, an end time indicating the end time of writing one stroke, the color of the stroke, A stroke width and coordinate array data ID for identifying an array of stroke passing points are shown.

  Further, the coordinate array data shows detailed information as shown in FIG. FIG. 7 is a conceptual diagram showing coordinate array data. As shown in FIG. 7, the coordinate array data includes one point (X coordinate value, Y coordinate value) on the display 3, and a time difference (ms from the disclosure time of the stroke when the one point is passed) ) And writing pressure information of the electronic pen 4 at this one point. That is, a collection of one point shown in FIG. 7 is represented by one coordinate array data shown in FIG. For example, when the user draws the alphabet “S” with the electronic pen 4, it is drawn with a single stroke, but passes through a plurality of passing points until the drawing of “S” is completed. Information.

Further, the media data in the page data shown in FIG. 5 shows detailed information as shown in FIG. FIG. 8 is a conceptual diagram showing media data. As shown in FIG. 8, the media data is stored in the page data storage unit 300 from the page processing unit 37, the media data ID in the page data shown in FIG. The recording time, the position of the image displayed on the display 3 by the page data (X coordinate value, Y coordinate value), the size of the image (width, height), and data indicating the contents of the media data are shown in association with each other. Has been. Among these, the position of the image displayed on the display 3 by the page data is displayed by the page data when the coordinates of the upper left corner of the display 3 are (X coordinate value, Y coordinate value) = (0, 0). The position of the upper left corner of the image to be displayed is shown.
Returning to FIG. 3, the remote license management table 310 manages license data necessary to execute the remote sharing process.

<Functional Configuration of File Processing Unit 40>
Next, the functional configuration of the file processing unit 40 shown in FIG. 3 will be described with reference to FIG. FIG. 4 is a functional block diagram of the file processing unit.
The file processing unit 40 includes a recovery unit 41, a file input unit 42a, a file output unit 42b, a file conversion unit 43, a file transmission unit 44, an address book input unit 45, a backup processing unit 46, a backup output unit 47, and a setting management unit 48. A setting file input unit 49a and a setting file output unit 49b. Furthermore, the file processing unit 40 includes an address book management table 410, a backup data storage unit 420, a setting file storage unit 430, and a connection destination management table 440.
Among these, the recovery processing unit 41 detects the abnormal end after the electronic blackboard 2 ends abnormally, and recovers the unsaved page data. For example, in the case of a normal end, the page data is recorded as a PDF file on the USB 5 via the file processing unit 40, but in the case of an abnormal end such as when the power is down, the page data is recorded in the page data storage unit 300. Has been done. Therefore, when the power is turned on again, the recovery processing unit 41 recovers by reading the page data from the page data storage unit 300.
The file input unit 42a reads a PDF file from the USB memory 5 and stores each page in the page data storage unit 300 as page data.

The file conversion unit 43 converts the page data stored in the page data storage unit 300 into a PDF format file.
The file output unit 42 b records the PDF file output by the file conversion unit 42 in the USB memory 5.
The file transmission unit 44 transmits the PDF file generated by the file conversion unit 43 by attaching it to an electronic mail. The transmission destination of the file is displayed by displaying the contents of the address book management table 410 on the display 3 by the display superimposing unit 36, and the file transmitting unit 44 accepts the selection of the destination by the operation of the input device such as a touch panel by the user. It is determined. In the address book management table 410, as shown in FIG. 11, the name of the destination and the mail address of the destination e-mail are managed in association with each other. Further, the file transmission unit 44 can accept an input of a mail address as a destination by an operation of an input device such as a touch panel by the user.
The address book input unit 45 reads a list file of e-mail addresses from the USB memory 5 and manages it in the address book management table 410.

The backup processing unit 46 performs backup by storing the file output by the file output unit 42 b and the file transmitted by the file transmission unit 44 in the backup data storage unit 420. If the user does not set backup, backup processing is not performed. The backup data is stored in the PDF format as shown in FIG.
The backup output unit 47 stores the backed up file in the USB memory 5. At the time of storage, a password is input for security by the operation of an input device such as a touch panel by the user.
The setting management unit 48 stores and reads various setting information of the electronic blackboard 2 in the setting file storage unit 430 for management. Examples of the various setting information include network settings, date and time settings, region and language settings, mail server settings, address book settings, connection destination list settings, and backup settings. The network setting is, for example, an IP address setting of the electronic blackboard 2, a net mask setting, a default gateway setting, a DNS (Domain Name System) setting, or the like.
The setting file output unit 49b records various setting information of the electronic blackboard 2 in the USB memory 5 as a setting file. Note that the settings file cannot be viewed by the user due to security.
The setting file input unit 49a reads a setting file stored in the USB memory 5 and reflects various setting information on various settings of the electronic blackboard.
The address book input unit 50 reads a list file of connection destination IP addresses for remote sharing processing from the USB memory 5 and manages it in the connection destination management table 440.

<Phase adjustment control>
FIG. 13 is a block diagram showing a characteristic configuration of the image processing apparatus according to the embodiment of the present invention.
The video acquisition unit 21 includes a PLL circuit 21a, a phase delay circuit 21b, and an A / D conversion circuit 21c.
The PLL circuit 21a generates a clock signal based on a horizontal synchronization signal (Hsync) added to, for example, an R / G / B signal that is a video signal input from the notebook PC 6. The PLL circuit 21a generates a clock signal having a frequency f extremely higher than the frequency fh of the horizontal synchronization signal by the VCO circuit, and compares the signal obtained by dividing the frequency f of the clock signal by an integer value with the horizontal synchronization signal. Thus, the differential voltage is obtained and fed back to the VCO circuit. As a result, a clock signal having a frequency locked to the frequency fh of the horizontal synchronization signal can be generated. Note that the PLL circuit 21a may be a digital PLL circuit.
The phase delay circuit 21b includes a delay circuit in which a plurality of delay elements are connected in series, and a selector circuit that selects clock signals having respective phases after delay according to the phase number. The phase delay circuit 21b passes the clock signal generated by the PLL circuit 21a to each delay element, selects the delay signal output from the output terminal of each delay element by the selector circuit, and performs A / D conversion as a sampling clock signal. Output to the circuit 21c. By setting a phase number for this selector circuit, a sampling clock signal having a desired phase can be output to the A / D conversion circuit 21c.

The A / D conversion circuit 21c, for example, samples each R / G / B signal that is a video signal input from the notebook PC 6 by using a sampling clock signal, performs analog / digital conversion, and is digitized. The R / G / B image data is output to the image processing unit 30.
The image processing unit 30 calculates a luminance change amount between two frames for the video signals stored in the frame memories F1 and F2 provided in the RAM 103.
The image processing unit 30 adds a luminance change amount ΔL as an average value obtained by dividing all the difference values for each pixel on the same coordinate between two frames of the image data input from the video acquisition unit 21 by the total number of pixels. Is stored in the RAM 103 in association with the phase number x.
The image processing unit 30 includes a resolution detection unit 30a that detects whether or not the resolution of the video signal has been changed based on a horizontal synchronization signal included in the video signal.
Specifically, the resolution detection unit 30a counts the number of horizontal synchronization signals included in the video signal to obtain a vertical resolution, and measures the period of one horizontal synchronization signal to obtain a pseudo horizontal resolution. The resolution is stored in the RAM 103 as the resolution. The resolution change flag is set to 0 when the previous resolution matches the current resolution, and the resolution change flag is set to 1 when they do not match. The resolution detection unit 30a sets the resolution change flag to 1 when a change in resolution is detected, and outputs it, while setting the resolution change flag to 0 when there is no change in resolution.

The phase adjustment control unit 29 determines the phase of the sampling clock signal based on the luminance change amount, and causes the video acquisition unit 21 to output the phase. The phase adjustment control unit 29 obtains the phase of the sampling clock signal that maximizes the amount of change in luminance, and causes the video acquisition unit to generate a sampling clock signal having an inverted phase obtained by inverting the phase.
The phase adjustment control unit 29 stores the phase number representing the phase of the sampling clock signal that maximizes the luminance change amount in the RAM 103 together with the luminance change amount, and the video acquisition unit displays the phase number representing the inverted phase obtained by inverting the phase. Set to 21. The phase adjustment control unit 29 obtains a value at which the current luminance change amount is maximized after a predetermined period elapses, and the value at which the current luminance change amount is maximized is the previous luminance change amount acquired from the RAM 103. When the value is larger than the value obtained, the setting in the video acquisition unit 21 is updated.
The phase adjustment control unit 29 does not update the setting in the video acquisition unit 21 when the value at which the current luminance change amount is maximum is smaller than the value at which the previous luminance change amount acquired from the RAM 103 is maximum. To control. When the resolution detection unit 30a detects that the resolution of the video signal has been changed, the phase adjustment control unit 29 restarts the setting update to the phase number to the video acquisition unit 21.

FIG. 14 is a flowchart showing a main operation of the phase adjustment control unit 29 according to the embodiment of the present invention. FIG. 15 is a flowchart showing an operation of a subroutine of the phase adjustment control unit 29 according to the embodiment of the present invention. The programs represented by the flowcharts shown in FIGS. 14 and 15 are stored in the ROM 102. The CPU 101 reads the operating system OS from the ROM 102, develops it on the RAM 103, starts up the OS, reads the program from the ROM 102 under the management of the OS, and executes phase adjustment processing.
In the present embodiment, in order to prevent flickering and fluctuation of a display image captured from a notebook PC 6 connected from the outside, when an analog video signal is input from the notebook PC to the image processing system, it is generated by the video acquisition unit 21. Adjust the phase of the sampling clock signal.

The main operation of the phase adjustment control unit 29 will be described with reference to FIG.
First, in step S100, the phase adjustment control unit 29, based on the current date and time read from the timer and the date and time of the previous phase adjustment process read from the RAM 103, for a certain period (for example, several Determine whether the time, days, etc. have passed. The phase adjustment control unit 29 proceeds to step S110 when the certain period has elapsed, and proceeds to step S105 when the certain period has not elapsed.
Next, in step S105, the phase adjustment control unit 29 determines whether there is a change in the resolution of the video signal. Here, when the resolution change flag acquired from the resolution detection unit 30a is 1, since the change of the resolution is detected, the process proceeds to step S110. On the other hand, if the resolution change flag is 0, the resolution is not changed, and the process returns to step S100.
In step S110, the phase adjustment control unit 29 calls a phase adjustment processing subroutine and proceeds to step S5 shown in FIG.

With reference to FIG. 15, the operation of the subroutine of the phase adjustment process will be described.
First, in step S5, the phase adjustment control unit 29 sets the phase number x = 0 as the initial phase of the sampling clock signal. Here, the phase adjustment control unit 29 sets the phase number x = 0 in the video acquisition unit 21 as the initial phase of the sampling clock signal. As a result, in the phase delay circuit 21b, the selector circuit selects and outputs the input signal of the first-stage delay element according to the phase number x = 0, and the sampling clock signal is changed to the initial phase (x = 0). . Thereby, the phase of the sampling clock signal generated by the video acquisition unit 21 is temporarily fixed.
Next, in step S10, in the phase adjustment control unit 29, the image processing unit 30 causes the frame memories F1 and F2 to acquire the luminance of all the pixels for two frames of the video. Here, a frame refers to a video (frame) of unit time.
Next, in step S15, the phase adjustment control unit 29 changes the luminance as an average value obtained by dividing the difference value for each pixel on the same coordinate between the two frames acquired by the image processing unit 30 by the total number of pixels. The amount ΔL is calculated and stored in the table (Table 1) of the RAM 103 in association with the phase number x.

Next, in step S20, the phase adjustment control unit 29 increments the phase number x.
Next, in step S25, the phase adjustment control unit 29 determines whether or not the incremented phase number x has reached a reference value n representing the required number of samples. Here, if the phase number x has not reached the reference value n, the phase adjustment control unit 29 proceeds to step S30. On the other hand, when the phase number x reaches the reference value n, the phase adjustment control unit 29 proceeds to step S35.
In step S30, the phase adjustment control unit 29 sets the phase number x in the video acquisition unit 21 in order to cause the video acquisition unit 21 to change the phase of the sampling clock signal in accordance with the incremented phase number x. Return to processing. As a result, in the phase delay circuit 21b, the selector circuit selects and outputs the output signal of the x-th delay element according to the phase number x, and the phase (x) of the sampling clock signal is changed.

On the other hand, when the phase number x reaches the reference value n, in step S35, the phase adjustment control unit 29 refers to the table of the RAM 103 (Table 1), and the luminance change amount ΔL between the two frames is maximized. The phase number x and the luminance change amount ΔL at that time are obtained.
Next, in step S40, the phase adjustment control unit 29 determines that the maximum luminance change amount ΔL obtained in step S35 is larger than the luminance change amount ΔLmax during the previous adjustment that is already stored in the RAM 103 at the present time. Determine whether or not. Here, the phase adjustment control unit 29 proceeds to step S45 when the maximum luminance change amount ΔL is larger than the luminance change amount ΔLmax at the previous adjustment. On the other hand, the phase adjustment control unit 29 ends the process when the maximum luminance change amount ΔL is equal to or smaller than the luminance change amount ΔLmax at the previous adjustment.
When the current maximum luminance change amount ΔL is larger than the previous luminance change amount ΔLmax, in step S45, the phase adjustment control unit 29 determines the current maximum luminance change amount ΔL as the luminance change amount. It is stored in the RAM 103 as ΔLmax.

  Next, in step S50, the phase adjustment control unit 29 shifts the phase setting of the video acquisition unit 21 by 2 / T with respect to the phase represented by the phase number x having the maximum luminance change amount ΔL. To update the process. Here, since T represents the cycle of the sampling clock signal, the phase shifted by 2 / T is a phase in which the phase of the sampling clock signal is shifted by a half cycle, that is, a phase obtained by inverting the phase represented by the phase number x.

Here, the phase table will be described with reference to Table 2.
In the phase table, each phase (°) in one cycle corresponding to each of the phase numbers 1 to m and an inverted phase number representing the inverted phase number are described. m is a natural number that is uniquely determined according to the delay time of one unit of delay elements constituting the phase delay circuit of the video acquisition unit 21 and the frequency of the sampling clock signal, and m is preferably an even number.
The phase adjustment control unit 29 reads out the inverted phase number from the phase table based on the phase number x having the luminance change amount ΔL that is the maximum this time, and acquires the video as the inverted phase number as the phase number x of the sampling clock signal. Set in part 21. As a result, the phase of the sampling clock signal output from the video acquisition unit 21 is changed to the inverted phase.
The phase adjustment control unit 29 sets the phase number x having the maximum luminance change amount ΔL in the video acquisition unit 21 and sets the phase of the clock signal output from the selector circuit of the phase delay circuit 21b. By passing the signal through the inverter circuit and inverting it, a sampling clock signal having an inverted phase may be generated and output to the A / D conversion circuit 21c.
According to the present embodiment, since the phase adjustment is performed at regular intervals, it is possible to specify the phase where the flickering or fluctuation of the display image is the largest at the timing when the luminance difference between the pixels at the same position between the two frames becomes large. Further, the inversion phase of the phase can be determined as the optimum phase.
In addition, whether or not the current phase is more appropriate than the phase determined in the previous phase adjustment is determined and updated only when the amount of change in luminance is larger. A more appropriate phase can be obtained.

FIG. 16 is a timing chart showing an example of the phase of the RGB signal and the phase of the sampling clock signal, and shows an example in which the setting of the phase of the sampling clock signal is appropriate for the phase of the RGB signal.
In FIG. 16, sampling (sample and hold) is performed at the timing when the voltage level of the RGB signal is flattened and converged at the rising edge of the sampling clock signal, so that it is acquired after A / D conversion by the A / D conversion circuit 21c. This shows that the obtained image data is stable.
FIG. 17 is a timing chart showing an example of the phase of the RGB signal and the phase of the sampling clock signal, and shows an example in which the sampling phase is inappropriate with respect to the phase of the RGB signal. In FIG. 17, since the voltage level of the RGB signal is sampled (sampled and held) at an unstable timing, the image data obtained after A / D conversion may vary from frame to frame. When such image data is displayed on the display, there is a problem in that the display image appears to fluctuate or flicker, resulting in poor visibility for the user. For this reason, it is necessary to adjust the phase of the sampling clock signal to an appropriate phase with respect to the phase of the RGB signal.

<Examples of Embodiments and Effects of the Present Invention>
<First aspect>
The image processing apparatus according to this aspect acquires a video signal, generates a sampling clock signal based on the video signal, and an image processing unit 30 that calculates a luminance change amount between two frames of the video signal. And a phase adjustment control unit 29 that determines the phase of the sampling clock signal based on the luminance change amount and outputs the phase from the video acquisition unit 21, and the phase adjustment control unit 29 has the maximum luminance change amount. The phase of the sampling clock signal to be obtained is obtained, and the video acquisition unit 21 is caused to generate a sampling clock signal having an inverted phase obtained by inverting the phase.
According to this aspect, the phase of the sampling clock signal that maximizes the amount of luminance change between two frames of the video signal is obtained, and the video acquisition unit generates a sampling clock signal having an inverted phase obtained by inverting the phase. The flickering and fluctuation of the display image can be prevented to the maximum. As a result, the visibility of the user can be improved.

<Second aspect>
The phase adjustment control unit 29 of this aspect stores the RAM 103 that stores the phase number representing the phase of the sampling clock signal that maximizes the luminance change amount together with the luminance change amount, and the phase number that represents the inverted phase obtained by inverting the phase. And setting means (step S50) for setting in the video acquisition unit 21.
According to this aspect, the phase number representing the phase of the sampling clock signal that maximizes the amount of change in luminance can be stored together with the amount of change in luminance, and the phase number representing the inverted phase obtained by inverting the phase can be stored in the video. By setting the acquisition unit 21, flickering or fluctuation of the display image can be prevented to the maximum.

<Third aspect>
The phase adjustment control unit 29 according to the present aspect obtains a value at which the current luminance change amount is maximized after a predetermined period has elapsed, and the value at which the current luminance change amount is maximized is acquired from the RAM 103. When the amount is larger than the maximum value, the setting in the video acquisition unit 21 is updated.
According to this aspect, since the phase adjustment is performed every predetermined period, it is possible to update the setting in the video acquisition unit 21 at some timing when it becomes larger than the maximum value of the luminance change amount until the previous time.

<4th aspect>
The phase adjustment control unit 29 according to the present embodiment sets the video acquisition unit 21 when the value at which the current luminance change amount is maximum is smaller than the value at which the previous luminance change amount acquired from the RAM 103 is maximum. It is characterized by not being updated.
According to this aspect, when the value at which the current luminance change amount is maximum is smaller than the value at which the previous luminance change amount is maximum, the display image is not updated by updating the setting in the video acquisition unit 21. Flicker and fluctuation can be prevented to the maximum.

<5th aspect>
The image processing unit 30 of this aspect includes a resolution detection unit 30a that detects whether or not the resolution of the video signal has been changed based on a synchronization signal included in the video signal, and the phase adjustment control unit 29 When the resolution is changed, the setting update to the video acquisition unit 21 is resumed.
According to this aspect, when the resolution of the video signal is changed, the optimum phase setting corresponding to the changed resolution of the video signal is performed by restarting the update of the setting to the video acquisition unit 21. Can do.

<Sixth aspect>
The image processing method of this aspect includes a video acquisition unit 21 that acquires a video signal and generates a sampling clock signal based on the video signal, and an image processing unit 30 that calculates a luminance change amount between two frames of the video signal. An image processing method of an image processing apparatus comprising:
A phase adjustment control step (S110) for determining the phase of the sampling clock signal based on the luminance change amount and outputting the phase from the video acquisition unit is provided, and the phase adjustment control step (S110) maximizes the luminance change amount. The phase of the sampling clock signal is obtained, and the video acquisition unit 21 is caused to generate a sampling clock signal having an inverted phase obtained by inverting the phase.
According to this aspect, the phase of the sampling clock signal that maximizes the amount of luminance change between two frames of the video signal is obtained, and the video acquisition unit generates a sampling clock signal having an inverted phase obtained by inverting the phase. The flickering and fluctuation of the display image can be prevented to the maximum. As a result, the visibility of the user can be improved.

<Seventh aspect>
The program according to this aspect is characterized by causing a processor to execute the steps according to the sixth aspect.
According to this aspect, by causing the processor to execute this program, the phase of the sampling clock signal that maximizes the amount of change in luminance between two frames of the video signal is obtained, and the sampling clock having the inverted phase obtained by inverting the phase The signal can be generated by the video acquisition unit, and flickering and fluctuation of the display image can be prevented to the maximum.

DESCRIPTION OF SYMBOLS 1 ... Image processing system, 2 ... Electronic blackboard, 3 ... Display, 4 ... Electronic pen, 5 ... USB memory, 6 ... Notebook PC, 7 ... Video conference terminal, 8 ... PC, 9 ... Communication network, 21a ... PLL circuit, 21b ... Phase delay circuit, 21c ... A / D conversion circuit, 29 ... Phase adjustment control unit, 30 ... Image processing unit, 30a ... Resolution detection unit, CPU ... 101, ROM ... 102, RAM ... 103

JP2012-053087A

Claims (7)

A video acquisition unit that acquires a video signal and generates a sampling clock signal based on the video signal;
An image processing unit for calculating a luminance change amount between two frames of the video signal;
A phase adjustment control unit that determines a phase of the sampling clock signal based on the luminance change amount and outputs the phase from the video acquisition unit;
The phase adjustment control unit
An image processing apparatus, comprising: obtaining a phase of the sampling clock signal that maximizes the amount of change in luminance; and causing the video acquisition unit to generate a sampling clock signal having an inverted phase obtained by inverting the phase. The phase adjustment control unit
Storage means for storing a phase number representing the phase of the sampling clock signal that maximizes the luminance change amount together with the luminance change amount;
The image processing apparatus according to claim 1, further comprising setting means for setting a phase number representing an inverted phase obtained by inverting the phase in the video acquisition unit. The phase adjustment control unit
After a predetermined period of time has elapsed, a value at which the current luminance change amount is maximized is obtained, and a value at which the current luminance change amount is maximized is a value at which the previous luminance change amount obtained from the storage means is maximized. The image processing apparatus according to claim 2, wherein the setting in the video acquisition unit is updated when the value is larger than the value. The phase adjustment control unit
The setting to the video acquisition unit is not updated when the value at which the current luminance change amount is maximum is smaller than the value at which the previous luminance change amount acquired from the storage unit is maximum. The image processing apparatus according to claim 3. The image processing unit includes resolution detection means for detecting whether the resolution of the video signal has been changed based on a synchronization signal included in the video signal,
The phase adjustment control unit
The image processing apparatus according to claim 4, wherein when the resolution of the video signal is changed, the setting update to the video acquisition unit is resumed. A video acquisition unit that acquires a video signal and generates a sampling clock signal based on the video signal;
An image processing method of an image processing apparatus comprising: an image processing unit that calculates a luminance change amount between two frames of the video signal,
A phase adjustment control step of determining a phase of the sampling clock signal based on the luminance change amount and outputting the phase from the video acquisition unit;
The phase adjustment control step includes:
An image processing method comprising: obtaining a phase of the sampling clock signal that maximizes the amount of change in luminance, and causing the video acquisition unit to generate a sampling clock signal having an inverted phase obtained by inverting the phase.   A program for causing a processor to execute the steps according to claim 6.

Images