JP4851860B2 - Projector and angle of view control method - Google Patents

Description

  The present invention relates to a projector that projects an image based on an input video signal.

  When a projector is installed, the distance between the projector and the screen (projection distance) and the angle at which the image from the projector is projected are arbitrarily set by the user. Recent projectors are provided with a digital zoom function and a trapezoidal distortion (keystone distortion) correction function in order to simplify the installation work of the projector by the user (see Patent Documents 1 and 2). Here, the trapezoidal distortion correction function is a function for correcting the keystone distortion of the screen that occurs when an image is projected from an oblique direction with respect to the screen. The digital zoom function is a function for enlarging or reducing an image while performing interpolation processing. When the display screen (projected image) protrudes from the screen frame, the user can adjust the display screen to fit within the screen frame by using the trapezoidal distortion correction function or the digital zoom function.

  10A and 10B are schematic diagrams for explaining the trapezoidal distortion correction processing, and FIGS. 10C and 10D are schematic diagrams for explaining the digital zoom processing.

  As shown in FIG. 10A, when the image P1 formed on the liquid crystal panel is projected on the screen from an oblique direction without the trapezoidal distortion correction process, the projected image T1 has a trapezoidal shape and protrudes from the image frame SC. In this case, trapezoidal distortion correction is performed on the image P1 so that the projected image T1 fits in the image frame SC. As shown in FIG. 10B, when the image P2 subjected to the trapezoidal distortion correction is projected, the projected image T2 fits in the image frame SC.

  Further, as shown in FIG. 10C, when the image P3 formed on the liquid crystal panel is projected onto the screen and the projection image T3 protrudes from the screen image frame SC, the projection image fits in the screen image frame SC. As described above, the image P3 is corrected by the digital zoom function. As shown in FIG. 10D, when the image P4 subjected to the digital zoom process is projected, the projected image T4 is within the image frame SC.

As described above, when the projected image extends beyond the screen image frame, the image formed on the liquid crystal panel is subjected to trapezoidal distortion correction processing or digital zoom processing, so that the display screen (projected image) is displayed on the screen. Can fit in a frame.
JP 2005-195969 A Special table 2002-527953 gazette

  However, the method of placing the display screen (projected image) in the image frame of the screen using the keystone distortion correction or digital zoom has the following problems.

  When image deformation processing by trapezoidal distortion correction or digital zoom is performed on an image (original image data) formed on a liquid crystal panel, the processed image data is deteriorated as compared with the original image data. For this reason, it may be difficult to see the projected image. In particular, when image transformation processing is performed on original image data including ruled lines, small characters, and halftone patterns, the image quality is easily deteriorated and the projected image is difficult to see.

  Note that image quality deterioration can be avoided by temporarily canceling the trapezoidal distortion correction and digital zoom. However, in this case, since the projected image protrudes from the screen frame, the user needs to re-install the projector. Such installation work is troublesome for the user.

  An object of the present invention is to provide a projector that solves the above-described problems, can store a projected image in a screen frame, and can suppress image quality deterioration of the projected image.

In order to achieve the above object, a projector according to the present invention provides:
A projector that projects an image formed on a liquid crystal panel,
A memory for storing image data;
The liquid crystal formed on the basis of the image data subjected to the deformation process while performing a deformation process on the image data stored in the memory so that the projected image to be projected falls within a predetermined display area. An angle-of-view conversion unit that acquires position information corresponding to the display area in the image on the panel, and determines an effective area on the image data stored in the memory based on the position information;
An image data extraction unit that extracts image data corresponding to an effective area determined by the angle-of-view conversion unit from the image data stored in the memory;
An image deformation mode and an image cropping mode can be set, and when the image deformation mode is set, an image based on the image data subjected to the deformation process by the angle-of-view angle conversion unit is formed on the liquid crystal panel, A control unit configured to form an image on the liquid crystal panel based on the image data extracted by the image data extraction unit when the image cutting mode is set.

  According to the above configuration, the mode can be switched between the image deformation mode in which the image deformation process is performed and the image cut-out mode in which the image deformation process is not performed. When the screen protrudes from the display area in the screen frame, the image transformation mode is set. When the image deformation mode is set, the display screen can be accommodated in a predetermined display area by the image deformation processing by trapezoidal distortion correction or digital zoom, so that it is not necessary to re-install the projector.

  In the state where the image deformation mode is set, if the screen becomes difficult to see due to image quality deterioration due to the image deformation process, the image cut mode is set. In the image cropping mode, only the image data corresponding to the display area in the screen frame is extracted from the image data stored in the memory, and the image based on the extracted image data is not subjected to image transformation processing. Project on the screen. Since image deformation processing is not performed, the image quality of the projected image does not deteriorate.

  According to the present invention, in addition to the existing effect that the screen can be easily adjusted to fit within the display area of the screen by the image deformation mode, the image cropping mode makes it difficult to see the projected image by the deformation process. There is an effect that it can be improved.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a projector according to an embodiment of the present invention. Referring to FIG. 1, the projector projects image light obtained by spatially modulating a light beam from a lamp 6 with a liquid crystal panel 7 onto a screen 9 with a projection lens 8, and the main part thereof is an image. Input unit 1, AD conversion unit 2, angle of view conversion unit 3, DA conversion unit 4, liquid crystal panel drive unit 5, on-screen display (OSD) 10, CPU 11, storage unit 12, key input unit 13, and image data extraction unit 14

  The video input unit 1 is supplied with a video signal (analog) from an external video signal source such as a personal computer. The video input unit 1 supplied to the video input unit 1 is supplied to the AD conversion unit 2. The AD conversion unit 2 converts the video signal supplied from the video input unit 1 into a digital signal. The digital video signal AD-converted by the AD conversion unit 2 is stored in the storage unit 12.

  The storage unit 12 includes memories a to c for holding a digital video signal and processing data and information related to the digital video signal. The memory a stores video data for one frame output from the AD conversion unit 2. The memory b stores trapezoidal distortion correction parameters set by the OSD 10. The memory c stores position information (effective area) related to the image frame of the screen 9 on the image data. The storage unit 12 also stores programs and data necessary for operating the projector.

  The key input unit 13 includes a key for executing each function of the projector and a key for inputting information. Examples of keys provided in the key input unit 13 include an up key, a down key, a left key, a right key, and an enter key. The OSD 10 displays on-screen menu information on the liquid crystal panel 7 when a predetermined key is pressed by the key input unit 13, and performs various settings based on information selected or input by the user according to the display menu. The on-screen menu information is, for example, pull-down menu information that includes a main menu and submenus. The user can make various settings related to image display (for example, settings related to image parameters such as aspect ratio and keystone) on the displayed on-screen menu. The trapezoidal distortion correction parameters set in the on-screen menu are stored in the memory b.

  The angle-of-view conversion unit 3 transforms the angle of view of the video signal converted into a digital signal, and acquires position information (effective area) on the liquid crystal panel. Here, the view angle transformation process of the video signal is a view angle transformation process by trapezoidal distortion correction or digital zoom. The position information (effective area) is position information on the liquid crystal panel 7 of the image data subjected to the deformation process, and corresponds to the image frame of the screen 9. The position information (effective area) is stored in the memory c. The image data extraction unit 14 extracts image data corresponding to the effective area stored in the memory c from the frame data stored in the memory a.

  The DA conversion unit 4 converts the image data (digital) that has been subjected to the view angle transformation process by the view angle conversion unit 3 or the image data (digital) extracted by the image data extraction unit 14 into an analog signal. The image data DA-converted by the DA conversion unit 4 is supplied to the liquid crystal panel drive unit 5. The liquid crystal panel drive unit 5 drives the liquid crystal panel 7 based on the image data supplied from the DA conversion unit 4.

  The CPU 11 controls the operation of the entire projector according to a program stored in the storage unit 12. The CPU 11 receives an input from the key input unit 13, receives the angle of view conversion unit 3, OSD 10, the storage unit 12, and data. The operation of each part of the extraction unit 14 is controlled. The image display mode includes an image deformation mode in which image display is performed based on the image data subjected to the view angle deformation process by the view angle conversion unit 3, and an image display based on the image data extracted by the image data extraction unit 14. There are image cutting modes to be performed, and the user can arbitrarily select these modes through the key input unit 13. The CPU 11 controls switching between the image deformation mode and the image cropping mode according to the mode selection input through the key input unit 13.

  Next, the operation of the projector of this embodiment will be specifically described.

[Image transformation mode]
When the user performs an input operation for selecting the image deformation mode on the key input unit 13, the CPU 11 accepts the input operation and sets the image display mode of the projector to the image deformation mode.

  The video signal supplied from the external video signal source in units of frames is supplied to the AD conversion unit 2 via the video input unit 1, and is converted into a digital signal by the AD conversion unit 2. The AD-converted video signal is temporarily stored in the memory a and then supplied to the angle-of-view conversion unit 3. The angle-of-view conversion unit 3 performs an image transformation process based on the correction parameters stored in the memory b on the supplied image data. The image data subjected to the image transformation process is converted into an analog signal by the DA converter 4 and then supplied to the liquid crystal panel drive 5. The liquid crystal panel drive 5 drives the liquid crystal panel 7 based on the supplied image data. Thus, an image is displayed on the screen 9.

  Since the memory b is in a default state when the projector is activated, the image transformation process by the angle-of-view conversion unit 3 is not performed. Therefore, depending on how the projector is installed with respect to the screen 9, trapezoidal distortion may occur in the display screen on the screen 9, and part of the screen may protrude from the image frame of the screen 9.

  As an example, FIG. 2A shows image data S (original image) stored in the memory a, FIG. 2B shows an image P5 formed on the liquid crystal panel, and FIG. 2C shows a display screen on the screen. T5 is shown respectively. The image data S shown in FIG. 2A is tabular information data including ruled lines and character data. When the image data S is displayed as it is without performing the image transformation process, a square image P5 as shown in FIG. 2B is formed on the liquid crystal panel. When the image P5 is projected obliquely upward toward the screen, a display screen T5 having a trapezoidal distortion as shown in FIG. 2C is displayed. In this example, a part of the display screen T5 is in a state of protruding from the screen image frame SC.

  As described above, when trapezoidal distortion occurs in the display screen and a part of the screen protrudes from the image frame, the user sets the trapezoidal distortion correction parameter as follows.

  When the user presses a key for displaying an on-screen menu at the key input unit 13, the OSD 10 displays on-screen menu information on the liquid crystal panel 7. The user performs each setting according to the display menu. One of these settings is a trapezoidal distortion correction parameter setting.

  FIG. 3A shows an example of a trapezoidal distortion correction parameter setting screen. This trapezoidal distortion correction parameter setting screen has a horizontal direction adjustment button for performing deformation in the horizontal direction (corresponding to the horizontal direction in the display image on the liquid crystal panel) for the image data, and for the image data. It has a vertical direction adjustment button for performing deformation in the vertical direction (corresponding to the vertical direction in the display image on the liquid crystal panel). These adjustment buttons are in the form of a so-called slider, and a desired numerical value of the parameter can be set by sliding the adjustment button. Next to the slider, a box in which the value of the parameter is displayed according to the position of the button is prepared, and the user can know the current set value from the parameter displayed in the box. In this example, it is possible to set trapezoidal distortion correction parameters in the horizontal direction and the vertical direction by sliding each adjustment button or pressing the left and right keys arranged on both sides of the adjustment button.

  FIG. 3B schematically shows changes in the shape of the image displayed on the liquid crystal panel when the trapezoidal distortion correction parameter is changed in four stages “0” to “3” in the vertical direction. . When the trapezoidal distortion correction parameter is set to “0”, a square image is displayed (the shape is the same as the original image). As the trapezoidal distortion correction parameter setting values gradually increase to “1”, “2”, and “3”, the trapezoidal distortion correction amount increases.

  In the projector, according to the set value of the correction parameter, the keystone distortion correction processing by the angle-of-view conversion unit 3 is performed in real time. The on-screen menu screen and the display screen based on the image data subjected to the deformation process can be simultaneously displayed on the screen. Therefore, the user can adjust the trapezoidal distortion of the display screen by sliding the horizontal adjustment button and the vertical adjustment button on the on-screen menu while watching these screens, and at the same time, the entire display screen is displayed on the screen. It can be adjusted so that it fits in the nine image frames.

  FIG. 2D shows an image displayed on the liquid crystal panel when trapezoidal distortion correction is performed, and FIG. 2E shows a display screen based on the image. The image shown in FIG. 2D is an image displayed on the liquid crystal panel when trapezoidal distortion correction is applied to the image data S shown in FIG. In this way, by applying the trapezoidal distortion correction, the display screen T6 in which the trapezoidal distortion is corrected is displayed on the screen in a size that just fits in the image frame SC.

  As described above, when the trapezoidal distortion correction parameter is set in the OSD 10, the CPU 11 stores the set parameter in the memory b. After setting the trapezoidal distortion correction parameters, the angle-of-view conversion unit 3 performs trapezoidal distortion correction on the image data read from the memory a based on the correction parameters stored in the memory b. Thus, the image with the trapezoidal distortion corrected is displayed on the screen 9 in a size that fits within the image frame.

  Further, in the process of performing the trapezoidal distortion correction based on the correction parameter, the angle-of-view conversion unit 3 detects the position information on the liquid crystal panel 7 of the deformed image data (the effective area indicated by the broken line in FIG. 2D). R). The effective area R in FIG. 2D corresponds to the effective area A on the screen shown in FIG. The effective area A is an area set in the image frame SC, and can be set to the same size as the image frame SC. The acquisition of the position information on the liquid crystal panel 7 is performed as follows.

  FIG. 4 schematically shows the trapezoidal distortion correction amount of the image formed on the liquid crystal panel. The correction amount of each line in the horizontal direction and the vertical direction is calculated for the image subjected to the trapezoidal distortion correction. The correction amount is an amount given by arrows a and b in the horizontal line L as shown in FIG. These correction amounts are calculated from the values of the trapezoidal distortion correction parameters set by the user using table information (stored in the storage unit 12) prepared in advance.

  FIG. 5 shows an example of a parameter correction amount table related to the vertical direction, and FIG. 6 shows an example of a parameter correction amount table related to the horizontal direction. 5 and 6, the values in the parameter column correspond to the values of the trapezoidal distortion correction parameters set by the user. For each parameter value, the correction amount (a, b) is set. This example is a correction amount of a liquid crystal panel having a panel resolution of 1024 × 768. For example, when the user sets the vertical correction parameter to “2” and the horizontal correction parameter to “3”, the angle-of-view conversion unit 3 sets the parameter “2” in the parameter correction amount table (vertical). The correction amount (a, b) in the column “” is acquired, and the correction amount (a, b) in the column “3” is acquired in the parameter correction amount table (horizontal). Then, the view angle conversion unit 3 calculates an effective area (area ABCD in FIG. 4) on the liquid crystal panel based on the acquired correction amount.

  The information on the effective area calculated by the angle-of-view conversion unit 3 as described above is stored in the memory c by the CPU 11. Here, the correction amount is calculated with reference to the table. However, when the correction amount changes according to a certain rule, the angle-of-view conversion unit 3 is based on a calculation formula corresponding to the rule. The correction amount may be calculated from the correction parameter set by the user.

The parameter correction amount tables shown in FIGS. 5 and 6 store the correction amounts (a, b) of each line for each correction parameter. Instead of this, the image correction amount table shown in FIG. A table storing the coordinates of the vertex ABCD for each correction parameter may be used.
[Image cropping mode]
When the user performs an input operation for selecting an image cropping mode on the key input unit 13, the CPU 11 accepts the input operation and sets the image display mode of the projector to the image cropping mode.

  In the image cropping mode, the video signal AD-converted by the AD converter 2 is temporarily stored in the memory a. The image data extraction unit 14 specifies an effective area on the image data stored in the memory a based on the position information of the effective area stored in the memory c. For example, as shown in FIG. 7A, when the effective area R1 on the liquid crystal panel is set by the angle-of-view conversion unit 3, the image data extracting unit 14 reads the position of the effective area R1 from the memory c. Get information. The image data extraction unit 14 then, based on the acquired position information of the effective area R1, as shown in FIG. 7B, the effective area S1 corresponding to the effective area R1 on the image data D in the memory a. Ask for. It is assumed that the addresses of the memory a and the pixels of the liquid crystal panel 9 are associated in advance.

  After obtaining the effective area S1, the image data extraction unit 14 supplies image data included in the effective area S1 among the image data stored in the memory a to the DA conversion unit 4. The DA conversion unit 4 converts the image data of the effective area S1 supplied from the image data extraction unit 14 into an analog signal. The DA-converted image data of the effective area S 1 is supplied to the liquid crystal panel drive 5. The liquid crystal panel drive 5 drives the liquid crystal panel 7 based on the supplied image data. As shown in FIG. 7C, an image based on the image data of the effective area S1 is formed on the liquid crystal panel 7, and a screen based on the image in the image frame is displayed on the screen 9.

  According to the projector of the present embodiment described above, as shown in FIG. 2C, trapezoidal distortion occurs in the screen T5 displayed on the screen, and a part of the screen is an image frame of the screen. When the user is out of the SC, the user selects the image deformation mode with the key input unit 13 and sets correction parameters using an on-screen menu. As a result, the display screen T6 with the trapezoidal distortion corrected as shown in FIG. 2E is displayed on the screen in a size that just fits within the image frame SC.

  On the display screen T <b> 6, when it is difficult to see information such as displayed characters due to image quality degradation due to image deformation processing, the user selects an image cropping mode using the key input unit 13. In the image cropping mode, an image based on the image data P7 included in the effective area S1 among the image data S shown in FIG. 2A is formed on the liquid crystal panel without performing image deformation processing. Then, as shown in FIG. 2G, the display screen T7 based on the image data P7 is displayed on the screen in a size that fits within the image frame SC.

  Note that the image data displayed on the display screen T7 is a part of the image data S that is the original image, and the remaining portion is not displayed. In the state in which the display screen T7 is displayed in the image cut-out mode, the user presses the up key, the down key, the left key, and the right key direction key on the key input unit 13 to thereby display the non-display portion. Can be displayed. Specifically, the non-display portion is displayed as follows.

  When the user presses any one of the up key, down key, left key, and right key on the key input unit 13, the CPU 11 moves the memory a in the direction specified by the pressed direction key. The position of the effective area S1 on the image data is offset. The offset amount may be a predetermined amount or an amount corresponding to the length of time that the direction key is pressed. The CPU 11 supplies the offset amount together with the control signal to the image data extraction unit 14. The image data extraction unit 14 extracts image data corresponding to the effective area whose position is offset by the CPU 11 from the image data stored in the memory a.

  FIG. 8A schematically shows the offset processing of the effective area S1. In the upper part of FIG. 8A, the offset direction and the offset amount specified by the direction key are shown as a two-dimensional vector composed of “dx” and “dy” components. In this example, the right key and the down key are pressed. The CPU 11 moves the position of the effective area S1 on the image data D stored in the memory a based on the offset direction and the offset amount specified by the direction key. Then, the image data extraction unit 14 supplies the image data D included in the moved effective area S <b> 2 of the image data D to the DA conversion unit 4. As a result, an image based on the image data of the effective area S2 is formed on the liquid crystal panel as shown in FIG. 8B. The position of the formed image is an image based on the image data of the effective area S1. Is the same as the formation position.

  According to this offset process, the user can display the non-displayed portion only by pressing the direction key. Specifically, as shown in FIG. 9, when the left key is pressed, a non-display portion on the left side of the screen can be displayed, and when the right key is pressed, a non-display portion on the right side of the screen can be displayed. You can display the non-display area at the top of the screen by pressing the up key.

  The above is an example of trapezoidal distortion correction. However, when digital zoom processing is performed, image quality deterioration due to deformation processing can be suppressed by performing similar processing.

  Further, although the image data is stored in the memory a in units of frames, the image data may be stored in units of fields. In this case, the operation can be described by replacing the frame with a field in the above description.

  The projector of the above-described embodiment is an example of the present invention, and the configuration and operation thereof can be changed as appropriate without departing from the spirit of the invention.

  The screen 9 may be a projection-dedicated screen or may be a structure such as a wall. In either case, an image frame is set on the screen.

  The key input unit 13 may be an operation unit provided in the projector main body, or may be a remote controller (remote controller) separate from the projector main body.

  The projector of the present invention can be applied to all projectors that project an image formed by a display device capable of spatial modulation such as a liquid crystal panel.

1 is a block diagram illustrating a schematic configuration of a projector according to an embodiment of the present invention. (A)-(g) is a schematic diagram for demonstrating operation | movement of the projector shown in FIG. (A) is a schematic diagram illustrating an example of a trapezoidal distortion correction parameter setting screen, and (b) is a schematic diagram illustrating a shape change of an image on a liquid crystal panel based on a trapezoidal distortion correction parameter. It is a figure for demonstrating the trapezoid distortion correction amount of the image formed on a liquid crystal panel. It is a figure which shows an example of the parameter correction amount table regarding a vertical direction. It is a figure which shows an example of the parameter correction amount table regarding a horizontal direction. (A)-(c) is a schematic diagram for demonstrating the image data extraction process performed in the image data extraction part shown in FIG. It is a figure for demonstrating the offset process of an effective area. It is a schematic diagram which shows the content of the screen displayed by an offset process. (A)-(d) is a schematic diagram for demonstrating the image deformation process of the existing projector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Video input part 2 AD conversion part 3 Angle of view conversion part 4 DA conversion part 5 Liquid crystal panel drive part 6 Lamp 7 Liquid crystal panel 8 Projection lens 9 Screen 10 On-screen display (OSD)
11 CPU
12 storage unit 13 key input unit 14 image data extraction unit

Claims (5)

A projector that projects an image formed on a liquid crystal panel,
A memory for storing image data;
The liquid crystal formed on the basis of the image data subjected to the deformation process while performing a deformation process on the image data stored in the memory so that the projected image to be projected falls within a predetermined display area. An angle-of-view conversion unit that acquires position information corresponding to the display area in the image on the panel, and determines an effective area on the image data stored in the memory based on the position information;
An image data extraction unit that extracts image data corresponding to an effective area determined by the angle-of-view conversion unit from the image data stored in the memory;
An image deformation mode and an image cropping mode can be set, and when the image deformation mode is set, an image based on the image data subjected to the deformation process by the angle-of-view angle conversion unit is formed on the liquid crystal panel, And a control unit configured to form an image on the liquid crystal panel based on the image data extracted by the image data extraction unit when the image cut-off mode is set. An input key for designating an offset direction and an offset amount of the image data displayed in the display area;
When the offset direction and the offset amount are designated by the direction key in a state where the image cut-off mode is set, the control unit, on the image data of the memory, based on the offset direction and the offset amount, Offset the position of the effective area determined by the angle of view converter,
The projector according to claim 1, wherein the image data extraction unit extracts image data corresponding to an effective area whose position is offset by the control unit from the image data stored in the memory.   The projector according to claim 1, wherein the image deformation process is a trapezoidal distortion correction process for correcting a trapezoidal distortion generated in the projected image to be projected.   3. The digital zoom process according to claim 1, wherein the image transformation process is a digital zoom process for enlarging or reducing an image on the liquid crystal panel displayed based on image data stored in the memory while performing an interpolation process. Projector. Based on the image data stored in the memory, an image is formed on the liquid crystal panel, and the image data stored in the memory is transformed so that a projected image obtained by projecting the image is within a predetermined display area. A first step of performing
Position information corresponding to the display area in the image on the liquid crystal panel formed based on the image data subjected to the deformation process is acquired, and on the image data stored in the memory based on the position information A second step of determining an effective area at
A third step of extracting image data corresponding to the effective area determined in the second step from the image data stored in the memory;
When an input for setting the image deformation mode is received, an input for forming an image based on the image data subjected to the deformation process in the first step on the liquid crystal panel and setting the image cropping mode And a fourth step of forming an image based on the image data extracted in the third step on the liquid crystal panel.

Images