KR100308579B1 - Device of horizontal scanning efficiency change for keystone distortion compensation of LCD projector - Google Patents

Abstract

According to the present invention, in the projection type display of an LCD projector, keystone distortion caused by adjusting the angle of the screen or the installation height of the LCD projector can be corrected by converting the horizontal scanning ratio according to the vertical direction of the image signal. The present invention relates to a horizontal scan rate converter for correcting keystone distortion.

Conventionally, in a projection display such as an LCD projector, keystone distortion occurs in the projected image due to the difference in the optical projection distance such as the installation angle of the screen and the position of the LCD projector. Solving the problem by adjusting the screen angle, height adjustment of the LCD projector, and shanghai east of the projection lens may cause inconvenience to the user and correct distortion.

According to the present invention, the keystone distortion caused by the difference in optical projection distance of the LCD projector is obtained by correcting a geometrically accurate calculation formula, that is, the keystone distortion angle by the user's OSD menu key 10 ( ), The horizontal distortion dots (hm) are detected by each vertical line (Vp), and then the horizontal scan rate (hcm) is converted to reflect the horizontal dot number (h) of the original video signal. By converting the horizontal scan rate of the signal to correct keystone distortion, the user can fine tune the distortion through the OSD menu key and easily and accurately correct the keystone distortion phenomenon.

Description

Device of horizontal scanning efficiency change for keystone distortion compensation of LCD projector

The present invention is to correct the keystone distortion of the LCD projector to correct the keystone distortion caused by the angle of the screen or the height of the installation of the LCD projector when the projection display such as the LCD projector is converted by converting the horizontal scan rate of the image signal A horizontal scan rate converter.

First, in a projection display device such as an LCD projector, when the LCD projector 2 is mounted on the pedestal 1 as shown in FIG. 1A or the ceiling 4 is installed as shown in FIG. It can be divided into

In the case where the LCD projector 2 is mounted on the base 1, the projected screen 5 by the improper angle adjustment between the screen 3 and the projection lens 2a of the LCD projector 2 is shown in FIG. As described above, a geometric distortion phenomenon (upper distortion; 5a) called Keystone is generated.

In addition, when the LCD projector 2 is mounted on the ceiling 4, the projected screen 5 by the improper angle adjustment between the screen 3 and the projection lens 2a of the LCD projector 2 is shown in FIG. As shown in b), the geometric distortion phenomenon (the lower distortion; 5b) called Keystone occurs.

Therefore, in the above two cases, an image is projected due to an improper angle adjustment between the screen 3 and the projection lens 2a of the LCD projector 2, that is, the difference in optical projection distance. , 5b) will occur.

As a basic method of correcting the keystone distortion, it can be divided into three types as shown in (a) (b) and (c) of FIG. 3.

The first is to adjust the angle of the screen (3) as shown in (a), the second to adjust the installation height of the LCD projector (2) as shown in (b), and the third to (c) as shown in (c). There is a method of adjusting the projection lens 2a of the projector 2 by moving the vertical position.

However, correcting the keystone distortion using the above methods is actually difficult to use and quite inconvenient. Particularly, in the third method, only the projection lens 2a is fixed while the installation height of the LCD projector 2 is fixed. As a result, there is a limit to correcting keystone distortion.

4 is a block diagram showing the configuration of a scanning rate converter of a conventional LCD projector;

A frame memory and a refresh rate converter 11 for converting and storing the refresh rates of the input video signals R _HV , G _HV , B _HV into video signals R _HcVc , G _HcVc , B _HcVc that match the output format; LCD driver 12 for projecting the converted image signals R _HcVc , G _HcVc , B _HcVc onto the LCD screen according to the synchronization signals H _C and V _C , and the horizontal and vertical synchronization signals H and V inputted. A timing adjusting unit 14 for converting the signals into sync signals Hc and Vc corresponding to the refresh rate-converted video signals R _HcVc , G _HcVc and B _HcVc and outputting them to the LCD driver 12, and the refresh rate converting unit 11. And a microcomputer 15 for outputting control data through the serial bus I ² C to control the timing adjusting unit 14.

Reference numeral 13 denotes a phase locked loop (PLL) unit that receives a horizontal synchronization signal H input to the timing adjusting unit 14 to generate an arbitrary frequency and output the random frequency.

The apparatus for converting a refresh rate of an LCD projector configured as described above will be described with reference to FIG.

First, the frame memory and the rate conversion unit 11 convert an input video signal (R _HV , G _HV , B _HV ) into a video signal corresponding to an output format by control data through the serial bus I ² C of the microcomputer 15. (R _HcVc , G _HcVc , B _HcVc ) converts and stores the refresh rate, and outputs the converted video signal to the LCD driver 12.

The timing adjusting unit 14 outputs the vertical synchronizing signal V and the horizontal synchronizing signal H through the PLL unit 13 based on the control data of the microcomputer 15 and outputs the image signals R _HcVc , G _HcVc and B. _HcVc ) is converted into synchronization signals Hc and Vc suitable for _HcVc and then output as synchronization signals of the LCD driver 12 by the clock signal CK.

In addition, the timing adjusting unit 14 outputs the horizontal synchronizing signal H to the frame memory and the rate converter 11 by the clock signal CK.

However, the image signals R _HcVc , G _HcVc , and B _HcVc output by the rate converter 11 are always constant along the vertical lines, so that the installation angle of the screen and the position of the LCD projector, that is, optical It is difficult to solve the geometric distortion phenomenon called keystone by the projection distance in circuit.

In order to solve the above problems, the present invention is to correct the keystone distortion by converting the horizontal scan rate along each vertical line of the image signal to project a different image signal for each vertical line, the optical projection distance After detecting the horizontal scan rate from the distortion angle and the relationship between the vertical angle and the horizontal dot number of the video signal, the horizontal scan rate of the video signal is measured for each vertical line by the detected horizontal scan rate. By converting and correcting the keystone distortion, the user can fine tune the keystone distortion angle on the OSD menu to provide the convenience of correcting the keystone distortion accurately and easily.

1 is a case where the LCD projector is installed on a pedestal,

(a) is a side view of the LCD projector installed for the base,

(b) shows the keystone distortion screen in the case of (a).

2 is a case of installing the LCD projector on the ceiling,

(a) is a side view of the LCD projector installed on the ceiling,

(b) is a keystone distortion screen in the case of Figure 2 (a).

3 is an example for showing a keystone distortion correction method of a conventional LCD projector;

(a) is an example of distortion correction by adjusting the angle of the screen,

(b) shows an example of distortion correction by adjusting the installation height of the LCD projector.

(c) shows an example of adjusting the projection lens of the LCD projector by moving it up and down.

Figure 4 is a block diagram for showing a refresh rate conversion apparatus of a conventional LCD projector.

5 is a block diagram showing a refresh rate converter for keystone distortion correction of an LCD projector of the present invention;

6 is a view for explaining the geometrical relationship between the keystone distortion of the present invention and the number of horizontal dots and vertical lines of a video signal;

The horizontal scan rate converter for keystone distortion correction of the LCD projector of the present invention is shown in FIG.

Keystone distortion angle according to user's OSD menu key (10) selection And the microcomputer 20 for outputting the variable,

A timing adjusting unit 40 for outputting the vertical synchronizing signal V and the horizontal synchronizing signal H, which are input, as the synchronizing signals Hc and Vc of the video signal according to the output format and outputting each vertical line Vp;

Keystone distortion angle output from the microcomputer 20 ( ) And each vertical line (Vp) by reflecting the horizontal dot number (h) of the image signal of the supporter that detects the horizontal distortion dot number (hm) using each vertical line (Vp) of the timing adjusting unit (40). A scanning rate converting means 50 for converting the horizontal scanning rate so that the image signal is projected differently every time;

LCD driver for projecting the image signals (R ' _HcVc , G' _HcVc , B ' _HcVc ) output from the refresh rate converting means (50) onto the screen by the synchronization signals (Hc, Vc) of the timing adjusting unit (40). 60).

And, the scanning rate converting means 50, the keystone distortion angle through the microcomputer 20 ( And the horizontal distortion dot number detecting unit 51 for detecting the horizontal distortion dot number hm that contributes to the keystone distortion by each vertical line Vp of the timing adjusting unit 40 and the vertical line Vp. The horizontal scan rate (hcm) subtracted from the horizontal dot number (h) of the original video signal by using the horizontal distortion dot number (hm) of the dot number detector 51 as the left and right horizontal distortion dot numbers (2hm). A horizontal scan rate detector 52, a rate converter 53 for converting the input video signals R _HV , G _HV , B _HV into a refresh rate suitable for the output images R _HcVc , G _HcVc , B _HcVc , and A horizontal scan rate corrector 54 for decimating the horizontal scan rate detected by the horizontal scan rate detector 52 for each vertical line of the converted video signal, and interpolated the lost information of the decimated video signal. The interpolation processing unit 55 corrected by the interpolation processing unit 55 and the image interpolated by the interpolation processing unit 55 Adjusting the arc horizontal dots so as to be arranged the same number to the left or right from the center of the screen, and then the final keystone distortion correction of an image signal _{(R 'HcVc, G' HcVc} , B 'HcVc) for outputting to the LCD driving unit 60 Frame memory 57 for storing the image data of the horizontal dot array unit 56, the refresh rate conversion unit 53, the horizontal scan rate correction unit 54, the interpolation processing unit 55, and the horizontal dot array unit 56. It consists of.

The horizontal distortion dot number detection unit 51 is a distortion angle of the microcomputer 20 ( Is an integer that takes only an integer of a distortion angle conversion unit 51a for calculating the ratio of the horizontal dot number h and the vertical line number V, A multiplier for determining the horizontal distortion dot number hm by multiplying the integer value for the distortion angle of the summation unit 51b and the distortion angle of the integerization unit 51b by the number of vertical lines Vp input from the timing adjusting unit 40. It consists of 51c.

The distortion angle conversion unit 51a is a distortion angle through the microcomputer 20 ( ) Tangent (tan) And the tangent (tan) ) Is proportional to the number of vertical lines (Vp) relative to the number of horizontal dots (hc).

The multiplier 51c is an integer distortion angle tan ) And the number of horizontal distortion dots (hm) proportional to the product of each vertical line (Vp).

The horizontal scanning rate (hcm) detected by the horizontal scanning rate detection unit 52 is a result value of hcm = h-2hm, where h is the number of horizontal dots of the original video signal, and 2hm is the number of horizontal distortion dots appearing on the left and right sides of the screen. to be.

The description of the same parts as in the related art for the horizontal scanning rate conversion device for keystone distortion correction of the LCD projector according to the present invention configured as described above will be omitted and described with reference to the accompanying drawings.

When upper or lower distortion occurs on the screen projected by the LCD projector, when the user selects the OSD menu key 10, the microcomputer 20 recognizes the distortion angle for keystone distortion correction ( ) Is outputted to the scanning rate converting means 50 while varying.

In addition, the microcomputer 20 outputs control data through the serial bus I ² C to the timing controller 40 and the scanning rate converting means 50 so that the input image is converted to the output image.

The timing adjusting unit 40 receives the vertical synchronizing signal V and the horizontal synchronizing signal H through the PLL unit 30, and adjusts the timing of the synchronizing signals H and V to the clock signal CK. The driving unit 60 outputs the horizontal and vertical synchronization signals Hc and Vc, and outputs the horizontal synchronization signal H to the scanning rate converting means 50.

In addition, the timing adjusting unit 40 outputs each vertical line Vp to the scanning rate converting means 50 so that the horizontal scanning rate hcm is converted along the vertical direction of the image signal.

Here, each vertical line Vp is a value obtained by subtracting the number V of the vertical lines from the nth vertical line Vn.

Then, the rate conversion means 50 is used to correct the keystone distortion of the projected image signal. ), The horizontal scan rate (hcm) of the video signal is converted from the relationship between the vertical line number (V) and the horizontal dot number (h) of the video signal, and after correcting the lost information of the converted video signal, Arranged as

Horizontal distortion number detection unit 51 of the rate conversion means 50 is the distortion angle (the input through the microcomputer 20) And each vertical line Vp inputted from the timing adjusting unit 40 to contribute to the keystone distortion at each horizontal line Vp of the video signal from the number of horizontal dots h of the original video signal. The horizontal distortion dot number hm is detected.

That is, the distortion angle conversion unit 51a of the horizontal distortion dot number detection unit 51 has a keystone distortion angle ( ) Tangent ), And the converted value is integerized by the integerizer 51b. The integerized value is multiplied by each vertical line Vp in the multiplier 51c and outputted as the number of horizontal distortion dots hm. Therefore, the number of horizontal distortion dots hm contributing to keystone distortion is detected for each vertical line Vp.

Where the distortion angle ( ) Is zero ('0'), the number of horizontal distortion dots (hm) becomes zero ('0') to become a projection screen without keystone distortion, and the distortion angle ( If is determined, the number of horizontal distortion dots (hm) changes in proportion to the value of each vertical line (Vp).

In addition, the horizontal distortion dot number hm is a keystone distortion value generated at one side of the screen.

The horizontal scanning rate detection unit 52 is set to the left and right horizontal distortion dot numbers 2hm, which is twice the horizontal distortion dot number hm obtained from the multiplier 51c of the horizontal distortion number detection unit 51. The horizontal distortion number (2hm) is subtracted from the horizontal dot number (h) of the original video signal to detect the horizontal scanning rate (hcm).

To explain this in detail, as an example of correcting the upper distortion 5b of the screen 5 projected on the screen 3 as shown in FIG.

The geometric distortion angle when the image signal having the horizontal dot number (h) and the vertical line number (V) is projected on the screen. In this case, the distortion angle (in the nth vertical line Vn) The geometric equation for detecting the number of horizontal distortion dots (hm) contributing to keystone distortion by

Here, Vp = V-Vn and hm is the number of horizontal distortion dots that contribute to the keystone distortion, the value of which takes only integers and discards the decimal point.

When the number of horizontal distortion dots (hm) contributing to keystone distortion is obtained as described above, the horizontal distortion rate (2hm) displayed on the screen is subtracted from the number of horizontal dots (h) of the original video signal. hcm) is detected.

Then, the horizontal scan rate hcm detected by the horizontal scan rate detector 52 can be obtained as shown in Equation 2 below.

Where distortion angle '' If = 0 ', the projection screen without keystone distortion (hcm = h) will be displayed. If the value of is determined, the number of horizontal distortion dots hm changes in proportion to the value of each vertical line Vp.

Also, the distortion angle ( ) Is a correction amount used directly to obtain a horizontal scan rate (hcm), so that the correction amount is controlled by controlling through the microcomputer 20.

In addition, the scanning rate converting means 50 measures the horizontal scanning rate (hcm) detected as described above by the horizontal scanning rate ( _hcm ) for each vertical line (Vp) of the image signals R _HcVc , G _HcVc , and B _{HcVc which have been converted} . After interpolation and interpolation process, the interpolated image is arranged in the center of the screen.

The refresh rate converter 53 converts the refresh rate of the input video signals R _HV , G _HV , B _HV into video signals R _HcVc , G _HcVc , B _HcVc that match the output format, and the horizontal scan rate corrector 54. The decimation is performed for each vertical line by the horizontal scan rate (hcm) detected by the horizontal scan rate detector 52 in the scan rate-converted image signal, and then output to the interpolation processor 55.

The interpolation processor 55 corrects the image information lost by decimation by interpolation, and the horizontal dot array unit 56 that receives the interpolated image signal changes an image signal by a horizontal scan rate for each vertical line. After adjusting the horizontal dots of the same number from left to right from the center of the screen (align) and then the final keystone distortion-corrected video signal (R ' _HcVc , G' _HcVc , B ' _HcVc ) is the LCD driver 60 Will output

Then, the image signals R ' _HcVc , G' _HcVc , B ' _HcVc , which are keystone distortion-corrected by the scanning rate converting means 50, are projected on the screen through the LCD driver 60 as shown in FIG. Keystone distortion caused by left and right is removed, and in this state, the user can adjust the OSD menu key 10 to perform finer keystone distortion correction.

Therefore, the distortion angle ( If there is a keystone-distorted projection screen, the horizontal dot number h of the original image signal is equal to the horizontal distortion dot number 2hm that contributes to the keystone distortion for each vertical line Vp of the image signal. By decimating, the horizontal scanning ratio is converted in accordance with the vertical direction of the video signal.

The horizontal scan rate-converted video signal is interpolated, and the horizontal number of horizontal dots (hcm) for each vertical line Vp is arranged so that the same number of horizontal dots are arranged from the center of the screen. = h-2hm = h-2Vptan The keystone distortion is corrected by allowing another image signal to be projected by.

The refresh rate converting means 50 includes a frame memory 57 for storing image information of the refresh rate converting unit 53, the horizontal scanning rate correcting unit 54, the interpolation processing unit 55, and the horizontal dot array unit 56. It will include.

The present invention detects the horizontal distortion dot number through geometric analysis of the keystone distortion caused by the difference in optical projection distance generated when using the LCD projector, and then uses the horizontal distortion dot number to adjust the horizontal scan rate in the vertical direction. By converting and correcting the distortion, the user can fine tune the distortion correction on the OSD menu, while correcting the distortion accurately and easily, thereby providing convenience and satisfaction to the projector user.

Claims (4)

In a projection display device such as an LCD projector, A microcomputer for varying and outputting a keystone distortion angle according to a user's OSD menu key selection, a timing controller for receiving horizontal and vertical synchronization signals and outputting the number of vertical lines, and the keystone distortion angle And a scanning rate converting means for detecting the horizontal distortion dot number by the number of vertical lines and converting the horizontal scanning rate so that a different image signal is projected for each vertical line by reflecting the number of horizontal dots of the original video signal. Horizontal scan rate converter to correct keystone distortion of LCD projector. 2. The apparatus of claim 1, wherein the scanning rate converting means comprises: a horizontal distortion dot detection unit for detecting the number of horizontal distortion dots contributing to keystone distortion according to the keystone distortion angle and the number of vertical lines; A horizontal scan rate detector for detecting a horizontal scan rate by subtracting a value twice the number from the horizontal dot number of the original video signal, a scan rate converter for converting a scan rate of an input video signal to an output video signal, and the scan rate conversion A horizontal scan rate correction unit for decimating the received video signal by the detected horizontal scan rate for each vertical line, and an interpolation processor for correcting information lost by decimation of the video signal by interpolation; The horizontal dots of the interpolated video signal are arranged in the same number from left to right from the center of the screen and then output to the LCD driver. A horizontal array for keystone distortion correction of an LCD (LCD) projector, comprising: a dot array unit, a refresh rate converting unit, a horizontal scanning unit correcting unit, an interpolation processing unit, and a frame memory for storing image data of a horizontal dot array unit; Refresh rate inverter. The method of claim 2, wherein the horizontal distortion dot number detector converts the distortion angle of the microcomputer into a tangent value proportional to the number of horizontal dots and vertical lines contributing to keystone distortion, and to the converted distortion angle value. A horizontal scan rate converter for correcting the keystone distortion of an LCD (LCD) projector, characterized by determining the number of horizontal distortion dots that contribute to keystone distortion by multiplying each vertical line inputted from a timing controller. The LCD projector according to claim 2, wherein the horizontal distortion dot number detected by the horizontal distortion dot number detection unit is varied by the keystone distortion angle through the microcomputer and is converted in proportion to the number of vertical lines. Horizontal scan rate converter for correction of keystone distortion.