JP3843902B2 - Projector to correct keystone distortion - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projector that performs trapezoidal distortion correction.
[0002]
[Prior art]
In recent years, the technology of projectors that display images by projecting light is becoming widespread. By using a projector, an image such as a presentation is displayed based on an image signal received from an information terminal such as a personal computer, or an image such as a television or movie is projected based on a video signal received from an AV device or the like. Can be.
[0003]
In a projector, a user may desire projection with a tilt angle. In the case of projection with a tilt angle, trapezoidal distortion occurs in the display image due to tilt projection. In order to compensate for this, a technique for performing projection by deforming an image in a display image is used.
[0004]
FIG. 16 is an explanatory diagram showing distortion correction for compensating for trapezoidal distortion. The image processing unit of the projector generates deformed corrected images N1h and R1h by deforming the images in the corrected images N1 and R1 so as to compensate for the trapezoidal distortion. A gap (hatched portion) generated by the deformation becomes a portion to be projected in black.
[0005]
At the time of normal display, the data of the corrected image N1 is supplied as it is to the liquid crystal panel to form a liquid crystal panel image N2. Further, when performing reverse display, the liquid crystal panel image R2 is formed based on the corrected image R1 by reversing the driving order of the liquid crystal cells. The deformation correction image R1h is turned upside down to become a deformation panel image R2h.
[0006]
FIG. 17 is an explanatory diagram showing an illuminance distribution when a projector is projected. In FIG. 17, the illuminance distribution of projection performed by the liquid crystal cell on the liquid crystal panel plane is shown as a ratio to the case of the central axis 50 position of the lens that performs projection. FIG. 17 also shows a position where the liquid crystal panel 40 is provided with respect to the central axis 50. In the liquid crystal panel 40, the left half and the right half are indicated by a liquid crystal panel image N2 during normal display and a liquid crystal panel image R2 during reverse display, respectively.
[0007]
The centroid 40x of the liquid crystal panel 40 is located above the central axis 50. From center axis 50 Also down This is because projection display is performed on the screen to be provided. As shown in FIG. 17, the illuminance decreases as the distance from the position of the central axis 50 increases. For this reason, the illuminance at the upper end of the liquid crystal panel 40 is low. In particular, the performance at the left and right ends is low.
[0008]
Note that the illuminance distribution substantially coincides with other display performance distributions related to resolution, lens flare, chromatic aberration, distortion, and the like. If the illuminance is high, the display performance of that part is high. In recent years, a projector using a projection optical system 54 that performs wide-angle projection has been desired. However, as the wide-angle projection is used, the display performance at the upper end of the liquid crystal panel 40 is significantly reduced. Here, when examining the deformed panel image N2h during normal rotation display, a lot of useful light rays near the lower end portion N2b are used, and use of light rays near the upper end portion N2t is missed. For example, the portion N2hT having an illuminance of 90% or less of the illuminance at the central axis 50 is extremely limited in the deformed panel image N2h.
[0009]
[Problems to be solved by the invention]
However, when examining the deformed panel image R2h at the time of reverse display, it is recognized that useful light rays near the lower end portion R2b are made useless, and light rays near the upper end portion R2t are used frequently. For example, a portion R2hT having an illuminance of 90% or less of the illuminance at the central axis 50 covers a considerable portion in the deformed panel image R2h.
[0010]
Here, it is also conceivable to perform image deformation in distortion correction with reference to the upper end portions N1t and R1t in FIG. In this way, the deformed panel image R2h at the time of reverse display can use a lot of useful light rays in the vicinity of the lower end portion R2b, and avoid using the light rays in the vicinity of the upper end portion R2t. However, this time, the deformed panel image N2h at the time of normal display makes useless light rays near the lower end portion N2b and uses many light rays near the upper end portion N2t.
[0011]
This problem is not limited to the case described above, and is a problem common to projectors that perform projection display while compensating for trapezoidal distortion caused by tilt projection. For example, it is a problem that occurs even when reverse display in the horizontal direction is performed.
[0012]
The present invention has been made to solve these problems, and an object of the present invention is to improve the image quality of projection display performed while compensating for trapezoidal distortion caused by tilt projection.
[0013]
[Means for solving the problems and their functions and effects]
In order to solve at least a part of the above problems, the following configuration is applied in the present invention.
The projector of the present invention
A projector that irradiates a light bundle and projects an image on a predetermined projection area in the light bundle,
The central axis of the lens that irradiates the light bundle and the centroid of the projection area are shifted by a predetermined distance,
An input unit for inputting image data representing the image;
A distortion correction unit that applies distortion correction to the image data to deform the image in the projection area so as to compensate for trapezoidal distortion that occurs in the projection area due to tilt projection in the direction in which the shift occurs;
A reverse instruction input unit for inputting an instruction as to whether or not to perform reverse display of the image;
A reversing unit for correcting the data after distortion correction so as to realize the reversal when an instruction to be reversed is input,
The distortion correction unit switches the distortion correction so that when the reverse display is instructed, the distance between the centroid of the image after deformation and the central axis is increased as compared with the case without the instruction. The gist is to do.
[0014]
By doing in this way, it is possible to achieve both display performance in the case of normal display and in the case of reverse display. This is because the arrangement of the image after deformation in the projection area can be switched based on the display performance distribution in accordance with the presence or absence of correction in the inverting unit.
[0015]
Here, there are various cases in which the data correction after distortion correction is performed so as to realize inversion. You may perform by rearranging the data for 1 screen memorize | stored in memory for every pixel. Alternatively, every time an input for one line is received, an inverted output may be performed for each line. Further, the driving order of the liquid crystal panel and other devices may be changed.
[0016]
In the projector of the present invention,
The distortion correction unit performs the deformation based on one side of the projection area when there is no instruction for the reverse display, and performs the deformation based on a side facing the one side when there is an instruction for the reverse display. It may be done.
[0017]
By doing in this way, it is possible to achieve both high display performance in the case of normal display and the case of reverse display. For example, the distortion correction unit may perform deformation with reference to the lower side of the projection area when there is no instruction for reverse display, and perform deformation with reference to the upper side when there is an instruction for reverse display.
[0018]
In the projector of the present invention,
The shift may include a vertical component, and the inversion may be a rotation transformation of 180 degrees or a symmetrical transformation about the horizontal axis.
[0019]
In the projector of the present invention,
The shift may include a horizontal component, and the inversion may be a 180 degree rotation transformation or a symmetric transformation about the vertical axis.
[0020]
For example, it is conceivable to use symmetrical transformation about the vertical axis when viewing an image that passes through the screen from the back side of the surface that is projected onto the screen. In addition, rotation conversion can be used when the projector is installed with the bottom surface facing the ceiling by rotating the projector 180 degrees around the projection direction. Further, it is conceivable that the symmetrical transformation about the horizontal axis is used when an image transmitted through the screen is viewed from the back side while being installed on the ceiling.
[0021]
The second projector of the present invention is
A projector that irradiates a light bundle and projects an image on a predetermined projection area in the light bundle,
The central axis of the lens that irradiates the light bundle and the centroid of the projection area are shifted by a predetermined distance,
An input unit for inputting image data representing the image;
A reverse instruction input unit for inputting an instruction as to whether or not to perform reverse display of the image;
When the image data is corrected and the instruction to reverse display is input, a pre-inversion unit that performs correction to represent the inverted image obtained by inverting the image;
And a correction unit that performs distortion correction for deforming the image in the projection area so as to compensate for trapezoidal distortion generated in the projection area due to tilt projection, on the image data or the corrected image data. And
[0022]
By doing in this way, it is possible to achieve both display performance in the case of normal display and in the case of reverse display. This is because the presence or absence of correction of the image data that realizes the inversion does not affect the arrangement of the deformed image in the projection area. It is possible to realize a desired arrangement of the deformed image in the projection area without any complexity. This is because it is not necessary to consider the case where there is an instruction to perform reverse display.
[0023]
There are various cases in which the pre-inversion unit generates the inverted image data. For example, the horizontal reversal may be performed using a line memory that stores image data for one line in the image. Further, a frame memory that stores image data for one image may be used to perform upside down inversion and rotation.
[0024]
Further, the pre-inversion unit may perform predetermined image processing together with the inversion. For example, it is conceivable to perform image processing for converting image data in MPEG format or encrypted image data into image data in a predetermined format. In general, the burden when performing the reversing process in addition to these image processes is smaller than the burden of performing the reversing process alone.
[0025]
Here, it is desirable that the pre-inversion unit avoids changing the driving order of other devices. For example, as described above, inversion display may be realized by inverting the driving order of the liquid crystal cells. However, such a change in the driving order affects the display characteristics of the liquid crystal panel, thereby causing problems related to display performance and adjustment work. It is desirable that the pre-inversion unit does not cause such a problem.
[0026]
The present invention can be configured in various modes such as an image projection method and a computer program for causing a computer to control the projector, in addition to the mode as a projector. Moreover, you may comprise as a signal which can be equated with the said computer program, and may comprise as a recording medium which recorded these computer programs.
[0027]
Here, the recording medium may be a flexible disk, CD-ROM, magneto-optical disk, IC card, ROM cartridge, punch card, printed matter on which a code such as a bar code is printed, an internal storage device of a computer (memory such as RAM or ROM). ) And various types of computer-readable media such as external storage devices.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of projectors.
A. First embodiment: Change of correction:
A1. Schematic configuration:
A2. Reversing LCD cell drive order:
A3. Distortion correction:
A4. processing:
B. Second embodiment: Horizontal tilt projection:
C. Third embodiment: Pre-inversion processing:
[0029]
A. First embodiment: Change of correction:
A1. Schematic configuration:
FIG. 1 is an explanatory diagram showing a schematic configuration of a projector. The projector 10 includes a receiver 12, an image processing unit 20, a drive unit 30, a liquid crystal panel 40, and a control unit 60. The projector 10 also includes an illuminating device 52 for irradiating the liquid crystal panel 40 with a light beam, and a projection optical system 54 for projecting transmitted light that has passed through the liquid crystal panel 40 onto the screen SC.
[0030]
The receiver 12 inputs image data via the image input terminal 13. As the image data, an analog image signal or digital image signal supplied from an information terminal such as a personal computer (not shown), or a video signal supplied from an AV device or the like can be used. The receiver 12 converts these signals into image data in a format that can be processed by the image processing unit 20.
[0031]
The control unit 60 is configured as a microcomputer including a CPU and a memory, and controls the image processing control unit 20, the drive unit 30, and the like. Further, the control unit 60 inputs user input via the remote controller 61. The user can set whether to perform reverse display or distortion correction by operating the remote controller 61.
[0032]
The image processing unit 20 has a function of adjusting the frame rate and clock frequency of image data. The frame memory 21 is used for the adjustment, and the image data is stored in the frame memory 21 and read out to the drive unit 30 for adjustment. At this time, a distortion correction process is performed so as to compensate for the trapezoidal distortion generated in the display image by tilt projection.
[0033]
The driving unit 30 generates a driving signal based on the image data adjusted by the image processing unit 20 and drives the liquid crystal panel 40. Note that the drive unit 30 has a function of realizing reverse display such as upside down display, left / right reverse display, and rotation display. Details of this function will be described later.
[0034]
The liquid crystal panel 40 modulates the light flux emitted from the illumination device 52 according to the drive signal generated by the drive unit 30. The liquid crystal panel 40 is a transmissive liquid crystal panel and is used as a light valve (light modulator). The liquid crystal panel 40 includes two-dimensionally arranged liquid crystal cells, and the drive signal specifies the modulation mode of each liquid crystal cell. Due to the set of modulated pixels of each liquid crystal cell, the light flux on the liquid crystal panel 40 forms a liquid crystal panel image.
[0035]
The projection optical system 54 includes a predetermined lens group. The projection optical system 54 projects and displays a liquid crystal panel image on the screen SC. The centroid of the display image displayed on the screen SC is located above the central axis 50 of the lens in the projection optical system 54. This is because the centroid of the liquid crystal panel 40 is provided at a position shifted from the central axis 50 in the vertical direction.
[0036]
A2. Reversing LCD cell drive order:
FIG. 2 is an explanatory diagram showing inversion display by changing the driving order for the liquid crystal panel. Here, a case where the display is reversed by rotating 180 degrees will be described. For example, when projection is performed with the projector 10 installed on the ceiling, the projector 10 is rotated 180 degrees around the projection direction, and the projector 10 is installed with the bottom surface facing the ceiling.
[0037]
The frame memory 21 stores image data representing an image (frame). An image is composed of a plurality of rows of scanning lines (lines). FIG. 2 shows the case where an image is composed of lines 1 to 4. The drive unit 30 reads the lines 1 to 4 in this order and generates a corresponding drive signal to drive the liquid crystal panel 40. Each line is a column of a plurality of pixels, and the driving unit 30 sequentially processes the pixels in each line.
[0038]
As shown in FIG. 2, the order of the drive signals for driving the liquid crystal cells is reverse in the case of the normal display and the case of the reverse display. By reversing the driving order of the liquid crystal cells, it is possible to form a liquid crystal panel image in which the order of each line and the order of the pixels in each line are reversed. That is, it is possible to form a liquid crystal panel image in which the image is rotated. Note that symmetry inversion and the like about the horizontal and vertical axes can be performed in the same manner.
[0039]
A3. Distortion correction:
FIG. 3 is an explanatory diagram showing details of the configuration of the image processing unit that switches the distortion correction mode.
First, an outline of the configuration shown in FIG. 3 will be described.
The clock generation mechanism CLK1 synchronizes the operations of the input address generation mechanism 22 and the receiver 12. The input address generation mechanism 22 generates a storage address for the frame memory 21. The image processing unit 20 stores the image data received from the receiver 12 at the address generated by the input address generation mechanism 22.
[0040]
The clock generation mechanism CLK2 synchronizes the output address generation mechanism 23 and the drive unit 30. The output address generation mechanism 23 generates a read address for the frame memory 21. The image processing unit 20 reads out image data stored in the frame memory 21 in accordance with the address generated by the output address generation mechanism 23 and inputs the image data to the driving unit 30.
[0041]
The control unit 60 causes each address generation mechanism 22 and 23 to generate a predetermined address by writing an instruction in a register included in each of the address generation mechanisms 22 and 23. Thereby, data exchange between the frame memory 21 and the receiver 12 and the drive unit 30 is controlled. Here, the control unit 60 sets the address generation mode of the output address generation mechanism 23, thereby realizing the output of the deformation correction image corresponding to the distortion correction. At this time, black output for filling a gap generated by the deformation is also performed. The information written in the register by the control unit 60 includes information on whether or not to perform distortion correction, and information on tilt angles when distortion correction is performed.
[0042]
Next, a function for switching the distortion correction mode will be described.
The control unit 60 has a function of switching the arrangement of the deformation correction image in the correction image input to the drive unit 30 by switching the address generation mode in the output address generation mechanism 23. The control unit 60 instructs the output address generation mechanism 23 to switch through the register. The instruction content of the control unit 60 includes information on whether or not the driving unit 30 reverses the driving order. The output address generation mechanism 23 switches the address generation mode when the drive unit 30 reverses the drive order.
[0043]
FIG. 4 is an explanatory diagram showing a liquid crystal panel image according to the correction switching. FIG. 4 shows the corrected images S1 and T1 output from the frame memory 21 and the liquid crystal panel images S2 and T2 that are formed on the liquid crystal panel 40 by the drive unit 30 based on these images. The correction image S1 and the liquid crystal panel image S2 are shown for the case of normal rotation display, and the correction image T1 and the liquid crystal panel image T2 are shown for the case of reverse display.
[0044]
In the case of normal rotation display, the deformation correction image S1h is arranged along the lower end S1b in the correction image S1. 16 If indicated It is the same. As a result, the deformed panel image S2h follows the lower end S2b in the liquid crystal panel image S2. The deformed panel image S2 uses many useful light rays near the lower end S2b.
[0045]
In the case of reverse display, the deformation correction image T1h follows the upper end T1t in the correction image T1. 16 If indicated Different from . Based on the corrected image T1, the drive unit 30 forms a liquid crystal panel image T2. Since the driving unit 30 performs the inversion, the deformed panel image T2h follows the lower end T2b in the liquid crystal panel image T2. The deformed panel image T2h uses many useful rays near the lower end T2b.
[0046]
Therefore, in this embodiment, the positions of the centroids Sx and Tx of the deformed panel images S2h and T2h with respect to the center axis 50 of the lens are the same in the case of normal display and the case of reverse display. In FIG. 4, the arrangement of the deformed panel images S2h and T2h in the liquid crystal panel images S2 and T2 is such that the distance between the centroids Sx and Tx and the central axis 50 of the lens is the smallest. However, the arrangement of the deformed panel images S2h and T2h shown in FIG. 4 in the liquid crystal panel images S2 and T2 is merely an example, and the present invention is not limited to this case.
[0047]
A4. processing:
FIG. 5 is an explanatory diagram showing the corrected image S1 during forward rotation display. FIG. 6 is an explanatory diagram showing the corrected image T1 during reverse display. FIG. 7 is a flowchart showing the deformation output process. FIG. 7 shows a flowchart of the process in which the frame memory 21 outputs the corrected image shown in FIGS. 5 and 6. Hereinafter, the output process of FIG. 7 will be described with reference to FIGS.
[0048]
In step Sa1, the output address generation mechanism 23 reads the tilt angle from the register. In step Sa2, it is checked whether or not to perform reverse display by reading the same register. In the case of normal display, the lower end reference deformation output processing of steps Sb0 to Sb4 is performed, and in the case of reverse display, the upper end reference deformation output processing of steps Sc1 to 5 is performed.
[0049]
First, the lower end reference deformation output process in the case of normal rotation display will be described. In step Sb0, the start line LA0 of the deformation correction image is prepared. As shown in FIG. 5, the start line LA0 is a line in which the upper end of the deformation correction image S1h is located in the correction image S1. The information of the start line LA0 is written in the register of the output address generation mechanism 23 by the control unit 60. A line LA0 in which the line LAn corresponding to the lower end of the deformation correction image S1h is the last line of the correction image S1 is written. In step Sb1, the start timing of outputting the corrected image S1 is detected from the clock generated by the clock generation mechanism CLK2. In step Sb2, black output is performed from the left end pixel St0 in the upper end line of the corrected image S1. In step Sb3, the output start timing of line LA0 examined in step Sb0 is detected from the clock.
[0050]
Thereby, in step Sb4, a process of outputting the deformation correction image S1h is performed. Specifically, the lines LA0 to LAn are output. In the case of the lower end reference deformation output process, the line LAn corresponding to the lower end of the deformation correction image S1h is the final line of the correction image S1. Specifically, the output end pixel is the pixel Stn, and the last pixel data Stnp stored in the frame memory 21 is output. Therefore, the process itself of outputting the corrected image S1 is completed by the end of the output process in step Sb4. The deformation-corrected image output process in step Sb4 will be described in detail later.
[0051]
Next, upper end reference deformation output processing in the case of reverse display will be described. In step Sc1, the start of frame output of the corrected image T1 is detected from the clock generated by the clock generation mechanism CLK2. In step Sc4, a process of outputting the deformation correction image T1h is performed. Specifically, the lines LB0 to LBn are output. The output start pixel is the pixel Tt0, and the first pixel data Tt0p stored in the frame memory 21 is output. The output in step Sc4 is performed up to the line Lbn corresponding to the lower end of the deformed panel image R1h. After the output up to the line LBn is finished, in Step Sc5, black output is performed until the timing for finishing the output of the corrected image T1 is detected. Specifically, black output is performed up to the pixel Ttn.
[0052]
FIG. 8 is a flowchart showing processing for outputting a deformation correction image. This shows the processing in steps Sb4 and Sc4 in FIG. That is, this is a process of outputting the lines LA0 to LAn or the lines LB0 to LBn one by one by the loop of steps Sd1 to Sd7. In the following description, it is assumed that the current output line is the line LA in FIG. 5 or the line LB in FIG.
[0053]
Step Sd1 detects the timing at which line output should start from the clock of the clock generation mechanism CLK2. Thereby, black output is performed in step Sd2. In the corrected image S1 shown in FIG. 5, black output is performed for the pixels La1 and La2, and in the corrected image R1 shown in FIG. 8, black output is performed for the pixels Lb1 and Lb2. The image processing unit 20 determines the position of the pixel La2 or Lb2 based on the current line LA or LB and the tilt angle.
[0054]
In steps Sd3 to Sd5, the pixels La2 to La3 or the pixels Lb2 to Lb3 are sequentially output. The output process is performed until the end of the output to the pixel La3 or Lb3 is detected in step Sd5. Further, the pixel output in steps Sd3 to Sd5 is performed so as to realize deformation of distortion correction. Specifically, pixel thinning is performed to shorten the shape in the horizontal direction, and several lines arranged in the vertical direction are condensed and output.
[0055]
In step Sd3, data to be read from the frame memory 21 for the current output pixel is specified. For example, in FIG. 5, the pixel data La2p is specified when the pixel La2 is output, and the pixel data La3p is specified when the pixel La3 is output. In step Sd4, the data is actually read from the frame memory 21 and output to the drive unit 30. Various methods can be considered for the output processing in steps Sd3 to Sd4.
[0056]
Finally, in step Sd6, black output is performed up to pixels La3 to La4 or pixels Lb3 to Lb4. This completes the output of the current lines LA and LB.
[0057]
The processing in steps Sd1 to Sd6 is performed until the end of output to the lines LAn and LBn is detected in step Sd7. If not completed, the process returns to step Sd1, and the next line is output.
[0058]
According to the projector in the present embodiment, it is possible to achieve both display performance in the case of the normal display and the case of the reverse display. This is because the arrangement of the deformed panel image in the liquid crystal panel image can be switched based on the distribution of display performance in accordance with the presence or absence of correction in the inverting unit.
[0059]
Various configurations of the projection optical system 54 can be considered. For example, in order to place the centroid of the display image at a position above the central axis 50, it is conceivable that the centroid of the liquid crystal panel image is below the central axis 50 of the lens in the projection optical system 54. Further, in FIG. 1 and the like, for convenience of illustration, the illumination device 52, the projection optical system 54, etc. are displayed considerably simplified. For example, the liquid crystal panel 40 actually performs light modulation for each color of RGB. Further, in the above description, the case where the reverse display is realized by changing the driving order of the liquid crystal cells has been described. However, the present invention is not limited to this case.
[0060]
Here, the configuration of the image processing unit and the like illustrated in FIG. 5 is merely an example, and for example, the output of the deformation correction image corresponding to the distortion correction may be realized by changing the address generation mode in the input address generation mechanism 22. . In the present embodiment, the case where the tilt projection direction is the vertical direction is illustrated, but the present invention is not limited to this case. For example, the same applies to the case of tilting projection in an oblique direction.
[0061]
B. Second embodiment: Horizontal tilt projection:
FIG. 9 is an explanatory diagram showing the projector 10a in which the centroid of the liquid crystal panel and the center axis 50a of the lens are displaced in the horizontal direction. FIG. 9 is a plan view of the projector 10a, the screen SC1, the viewers pp1 to pp3, and the like viewed from above.
[0062]
The screen SC1 is provided in a show window installed on the outer wall Wall of the building. The projector 10a of FIG. 9 performs projection display on the screen SC1 from the space in in the building. Visitors pp1 to pp3 viewing from the space out outside the building view images displayed through the screen SC1. As shown in FIG. 9, the projector 10a performs left-right reverse display of an image when projected from the back side of the screen as shown in FIG. Note that the projector 10a has a function of performing normal display as well as horizontal reversal display.
[0063]
The schematic configuration of the projector 10a is the same as that of the projector 10 in the first embodiment, and has a distortion correction function and other functions. However, the projector 10a is different from the first embodiment in which an image is displayed on the screen SC installed on the upper side in that the image is displayed on the screen SC1 installed on the right side of the central axis 50a when viewed from the projector 10a. .
[0064]
FIG. 10 is an explanatory diagram showing a liquid crystal panel image corresponding to the horizontal tilt. In the case of normal display, the deformation correction image V1h is arranged along the left end V1L in the correction image V1. Accordingly, the deformed panel image V2h is arranged along the left end V2L in the liquid crystal panel image V2. In the reverse display, the deformation correction image W1h is arranged along the right end W1R in the correction image W1. Thereby, the deformed panel image W2h is arranged along the left end W2L in the liquid crystal panel image W2. This is because during the reverse display, as in the case of the first embodiment, the liquid crystal panel image W2 obtained by inverting the correction image W1 is formed by changing the driving order of the liquid crystal cells.
[0065]
Accordingly, the positional relationship between the centroids Vx and Wx of the deformed panel images V2h and W2h and the center axis 50a of the lens is the same in both the normal display and the reverse display.
[0066]
FIG. 11 is an explanatory diagram showing a correction image corresponding to the horizontal tilt in the case of normal rotation display. FIG. 12 is an explanatory diagram showing a correction image corresponding to the horizontal tilt in the case of reverse display. FIG. 13 is a flowchart showing the deformation output process corresponding to the horizontal tilt. The process shown in FIG. 13 will be described with reference to FIGS. 11 and 12.
[0067]
Step Se1 and Step Se2 correspond to Step Sa1 and Step Sa2 in FIG. 7, respectively. In the case of normal display, the left end reference deformation output processing in steps Sf1 to Sf7 is performed, and in the case of reverse display, the right end reference deformation output processing in steps Sg0 to Sg7 is performed.
[0068]
First, the left end reference deformation output process at the time of forward display will be described. First, in step Sf1, the start of frame output is detected. Thereafter, the processes of steps Sf2 to Sf7 are repeatedly performed to output the lines LC0 to LCn. Hereinafter, the process for the current line LC shown in FIG. 11 will be described as an example.
[0069]
In step Sf2, the start timing of line output is detected. In step Sf5, the outputs of the pixels Lc1 to Lc3 of the deformation correction image V1h and the black output of the pixels Lc3 to Lcm are performed. Specifically, the output is performed by the line image output process shown in FIG. Here, in the line image output processing, black output of the pixels Lc1 to Lc2 is performed in step Sd2, pixels Lc2 to Lc3 are output in steps Sd3 to Sd5, and black output of the pixels Lc3 to Lcm is performed in step Sd6. If all the deformed panel images V1h are output and it is detected in step Sf7 that the processing up to the line LCn has been completed, the deforming output processing ends.
[0070]
Next, the right end reference deformation output process at the time of reverse display will be described. In step Sg0, the start distance h is prepared. The start distance h shown in FIG. 12 is the distance between the pixel at which the left end W1hL of the deformed panel image W1h is located and the left end W1L of the liquid crystal panel image W1. The output address generation mechanism 23 reads the information of the start distance h from the register, similarly to the process at step SC0 in the process shown in FIG. The control unit 60 writes the start distance h such that the right end of the deformation correction image W1h becomes the right end of the correction image W1 in the register of the output address generation mechanism 23. First, in step Sg1, the start of frame output is detected. Thereafter, the processes of steps Sg2 to Sg7 are repeated to sequentially output the lines LD0 to LDn. In the following, the process for the current line LD shown in FIG. 12 will be described as an example.
[0071]
Step Sg2 detects the start timing of line output in the same manner as step Sd1 in FIG. In steps Sg3 to Sg4, black output of the pixels LdM to Ld1 is performed. In step Sg5, the pixels Ld1 to Ld3 in the deformation correction image W1h are output. Specifically, the output is performed by the line image output process shown in FIG. In the line image output process, the pixels nLd1 to Lc2 are output in Steps Sd3 to Sd5, and the black output of the pixels Ld3 to LdM is performed in Step Sd6. If it is detected in step Sg7 that all of the deformed panel image W1h has been output, the deformed output process ends.
[0072]
B. Third embodiment: Pre-inversion processing:
FIG. 14 is an explanatory diagram showing a schematic configuration of the projector 10b that performs the pre-inversion process. The schematic configuration of the projector 10b in this embodiment is different from the projector 10 in the previous embodiment in that it includes a reversing unit 100b. The control unit 60b gives an instruction for reverse display not to the drive unit 30b but to the reverse unit 100b. The inversion unit 100b has a frame memory 11b, and performs pre-inversion processing using the frame memory 11b. The frame memory 11b has a function of storing two frames. In the pre-inversion process, the image data received from the receiver 12b is inverted. Further, in this embodiment, the order of the liquid crystal cell driving performed by the driving unit 30b is constant regardless of whether the display is normal or inverted.
[0073]
The reversing unit 100b performs reading from another frame while writing to one frame. The forward scan writing and the reverse scan reading are performed while alternately changing the frames to be read and written for each frame. In this way, the inversion unit 100b inverts and outputs the input image with a time delay corresponding to one frame. However, when the control unit 60b instructs normal display, the reversing unit 100b outputs the image as it is without reversing.
[0074]
FIG. 15 is an explanatory diagram showing the reverse display by the pre-inversion process. For the normal display and the reverse display, the receiver input image input by the receiver 12b, the reverse image output by the reverse unit 100b, and the corrected image output by the image processing unit 20b are shown. As described above, in the present embodiment, the drive unit 30b causes the liquid crystal panel 40b to directly form the corrected image as a liquid crystal panel image. The driving unit 30b does not change the driving order of the liquid crystal cells.
[0075]
In the case of reverse display, the reversing unit 100b performs reversal by pre-reversal processing and outputs the result. In the case of normal display, the receiver input image is output to the image processing unit 20b as it is. The image processing unit 20b performs distortion correction processing based on the inverted portion image and outputs corrected images Y and Z. When the distortion correction is performed, the deformation correction images Yh and Zh obtained by deforming the inverted part image are arranged in the correction images Y and Z.
[0076]
The correction images Y and Z shown in FIG. 15 are the same as those in the first embodiment in that the deformation correction images Yh and Zh are included therein. In the case of normal display, the corrected image Y is the same as the corrected image N1 in the first embodiment.
[0077]
However, the case of reverse display is different from the case of the first embodiment in that the deformation correction image Y2 is attached to the lower end Zb. From this, the liquid crystal panel image in the case of reverse display in the present embodiment is the same as the corrected image T2 in the first embodiment (see FIG. 4). In the first embodiment, the drive unit 30 inverts the correction image T1 to form the liquid crystal panel image T2. In the present embodiment, not only for the image formed on the liquid crystal panel 40b but also for the corrected image output from the image processing unit 20b, the centroid position of the image is different between the case of reverse display and the case of normal display. It is different from the case of the first embodiment in that it is the same.
[0078]
In the case of the first embodiment, the deformation output process in the projector 10b according to the present embodiment always performs the lower end reference deformation output process (steps Sb0 to Sb4) regardless of whether the normal display or the reverse display is performed (FIG. 7). Is different. That is, the branch process in step Sa2 is not performed.
[0079]
According to the projector in the present embodiment, it is possible to achieve both display performance in the case of the normal display and the case of the reverse display. Whether or not to perform the process of realizing the inversion does not affect the arrangement of the deformed panel image in the liquid crystal panel image. The desired arrangement of the deformed panel image in the liquid crystal panel image can be realized without complication.
[0080]
In the above description, the case where the position of the centroid of the deformed panel image is the same in the case of the normal display and the case of the reverse display is illustrated, but the present invention is not limited to this case. Further, the deformed panel image need not follow the lower end of the liquid crystal panel image.
[0081]
As mentioned above, although the various Example of this invention was described, it cannot be overemphasized that this invention is not limited to these Examples, and can take a various structure in the range which does not deviate from the meaning.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a schematic configuration of a projector.
FIG. 2 is an explanatory diagram showing image display by changing the driving order for the liquid crystal panel 40;
FIG. 3 is an explanatory diagram illustrating details of a configuration of an image processing unit that switches modes of distortion correction.
FIG. 4 is an explanatory diagram showing a liquid crystal panel image according to correction switching.
FIG. 5 is an explanatory diagram showing a corrected image at the time of normal display.
FIG. 6 is an explanatory diagram showing a corrected image at the time of reverse display.
FIG. 7 is a flowchart showing a modified output process.
FIG. 8 is a flowchart illustrating a process for outputting a deformation correction image.
FIG. 9 is an explanatory diagram showing a projector 10a in which the centroid of the liquid crystal panel and the center axis of the lens are displaced in the horizontal direction.
FIG. 10 is an explanatory diagram showing a liquid crystal panel image corresponding to a horizontal tilt.
FIG. 11 is an explanatory diagram illustrating a case where a correction image corresponding to horizontal tilt is displayed in a normal rotation.
FIG. 12 is an explanatory diagram showing a correction image corresponding to the horizontal tilt in the case of reverse display.
FIG. 13 is a flowchart showing a deformation output process corresponding to a horizontal tilt.
FIG. 14 is an explanatory diagram showing a schematic configuration of a projector 10b that performs a pre-inversion process.
FIG. 15 is an explanatory diagram showing inversion display by pre-inversion processing;
FIG. 16 is an explanatory diagram showing distortion correction for compensating for trapezoidal distortion.
FIG. 17 is an explanatory diagram showing an illuminance distribution when a projector is projected.
[Explanation of symbols]
10. Projector
12 ... Receiver
20: Image processing unit
21 ... Frame memory
22: Input address generation mechanism
23 ... Output address generation mechanism
30 ... Drive unit
40 ... LCD panel
50 ... Center axis of lens
54. Projection optical system
60 ... Control unit
61 ... Remote control
CLK1, CLK2 ... Clock generation mechanism
LB0 ... Start line
S1, T1 ... corrected image
S1h, T1h ... deformation correction image
S2, T2 ... LCD panel image
S2h, T2h ... Deformed panel image
Sx, Tx ... centroid of deformed panel image
10a ... Projector
50a ... Center axis of lens
10b ... Projector
pp1, pp2, pp3 ... Viewers of images displayed transparently
V1, W1 ... corrected image
V1h, W1h ... deformation correction image
V2, W2 ... LCD panel image
V2h, W2h ... Deformed panel image
Vx, Wx ... Deformed panel image centroid
h: Starting distance
12b ... Receiver
20b ... Image processing unit
30b ... Drive unit
40b ... Liquid crystal panel
60b ... Control unit
61b ... Remote control
100b ... reversing part
11b Frame memory
Y, Z ... Corrected image
Yh, Zh ... deformation correction image
N1, R1 ... corrected image
N1h, R1h ... deformation correction image
N2, R2 ... LCD panel image
N2h, R2h ... Deformed panel image
N2ht, R2ht ... The part where the illuminance is 90% or less
40x ... centroid of LCD panel

Claims (7)

A projector that projects an image by irradiating a projection area on a screen with a light beam modulated by a light modulation panel,
  The center of the light modulation panel is shifted from the central axis of the lens for irradiating the light bundle,
  A distortion correction unit for forming a deformed panel image obtained by deforming the image on the light modulation panel so as to compensate for the trapezoidal distortion of the projection area caused by the tilt projection when tilting projection is performed;
  The projector is capable of normal display and reverse display in which the normal display is inverted in at least one of the vertical and horizontal directions,
  The distortion correction unit is arranged at a position where the center of gravity of the deformed panel image is shifted from the center of the light modulation panel toward the center axis of the lens in both the normal display and the reverse display. As described above, when the normal display is performed, the image is deformed by the normal correction process to form the deformed panel image on the light modulation panel, and when the reverse display is performed, the image is corrected by the reverse correction process. A projector that deforms the image to form the deformed panel image on the light modulation panel. The projector according to claim 1, wherein
  The distortion correction unit
  An image processing unit that includes a deformation correction image obtained by deforming the image, and outputs a correction image representing an image formed on the entire surface of the light modulation panel;
  A light modulation panel driving unit that outputs the correction image output by the image processing unit to the light modulation panel and forms a light modulation panel image represented by the correction image on the light modulation panel;
  The distortion correction unit converts the deformation correction image into the correction image so that the center of gravity of the deformation correction image in the forward correction processing and the center of gravity of the deformation correction image in the reverse correction processing are different from each other. Placed inside,
  The projector, wherein the light modulation panel drive unit reverses the light modulation panel image by changing a drive order of the light modulation panel between the normal rotation correction process and the reverse correction process. The projector according to claim 2, wherein
  The deformation process of the image in the normal rotation correction process is to deform the image so that the first side of the image is in contact with one side of the correction image,
  The projector in which the deformation process of the image in the inversion correction process deforms the image so that a second side of the image facing the first side is in contact with one side of the corrected image. The projector according to claim 1,
  The distortion correction unit is a non-inverted image that does not invert the image, and an inverted image in which the image is inverted.
  An image processing unit that generates a corrected image representing an image formed on the entire surface of the light modulation panel by deforming an image output from the reversing unit,
  In the forward rotation correction process, the reversing unit outputs the non-reversed image, and in the reverse correction process, the reversing unit outputs the reversed image. A method of projecting an image by irradiating a projection area on a screen with a light beam modulated by a light modulation panel,
  The center of the light modulation panel is shifted from the central axis of the lens for irradiating the light bundle,
  A distortion correcting step of forming a deformed panel image obtained by deforming the image on the light modulation panel so as to compensate for the trapezoidal distortion of the projection area caused by the tilt projection when tilt projection is performed; ,
  The distortion correction step includes
  When performing normal display so that the center of gravity of the deformed panel image is shifted from the center of the light modulation panel to the center axis side of the lens, the image is deformed by normal correction processing. And forming the deformed panel image on the light modulation panel;
  Inversion in which the normal display is inverted in at least one of the vertical direction and the horizontal direction so that the center of gravity of the deformation panel image is disposed at a position shifted from the center of the light modulation panel toward the center axis of the lens. Forming the deformed panel image on the light modulation panel by deforming the image by inversion correction processing when displaying; and
Including a method. A computer program for causing a computer to control a projector that projects an image by irradiating a projection area on a screen with a light beam modulated by a light modulation panel,
  The projector is
  The center of the light modulation panel is deviated from the central axis of the lens for irradiating the light bundle;
  The computer program has a distortion correction function for forming a deformed panel image obtained by deforming the image on the light modulation panel so as to compensate for a trapezoidal distortion of the projection area caused by the tilt projection when tilt projection is performed. Is equipped with a computer program that realizes
  A computer program for causing a computer to realize the distortion correction function is as follows.
  When performing the normal rotation display, the image is deformed by normal rotation correction processing so that the center of gravity of the deformation panel image is arranged at a position shifted from the center of the light modulation panel to the center axis side of the lens. A function of forming the deformation panel image on the light modulation panel;
  Inversion in which the normal display is inverted in at least one of the vertical direction and the horizontal direction so that the center of gravity of the deformation panel image is disposed at a position shifted from the center of the light modulation panel toward the center axis of the lens. A function of deforming the image by reversal correction processing when displaying and forming the deformed panel image on the light modulation panel;
A computer program, including a computer program that causes a computer to realize the above.   A computer-readable recording medium on which the computer program according to claim 6 is recorded.

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