KR20040078280A - Apparatus and Method for Compensate Image of Projector - Google Patents

Abstract

PURPOSE: An apparatus and a method for correcting a picture of a projector are provided to adjust contrast and gamma data in response to a picture size to produce an optimum picture. CONSTITUTION: A picture correcting apparatus includes a distance measuring sensor(110), a memory(120), a contrast controller(130), a gamma controller(140), a controller(100) and a driver(150). The distance measuring sensor senses a distance between zoom lenses of a projector. The memory stores contrast control data and gamma control data in response to magnifying factors of the zoom lenses. The contrast controller has the contrast control data for controlling contrast of a picture projected on a screen. The gamma controller has the gamma control data for controlling gamma characteristic of the picture projected on the screen. The controller calculates the magnifying factors of the zoom lenses based on the distance sensed by the distance measuring sensor and resets the contrast control data and the gamma control data in response to the calculated magnifying factors. The driver adjusts contrast and gamma characteristic of the picture in response to the reset contrast control data and gamma control data.

Description

Screen compensator of projector and its method {Apparatus and Method for Compensate Image of Projector}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projector, and more particularly, to an apparatus and a method for calibrating a projector to realize an optimal screen by adjusting contrast and gamma data according to a screen size.

In general, due to the limitation of the screen size of the existing TV, the development of a projection display system is prominent while the development and release of a large screen, ultra-thin display is active.

In such a projection display system, the development and spread of a projector using liquid crystal display (LCD) or digital light processing (DLP) and the like are rapidly increasing.

In such a projection display system, the development and spread of a projector using liquid crystal display (LCD) or digital light processing (DLP) is rapidly increasing, which is a presentation in schools, corporations, and public offices. It is not only universally used to display the output screen of city PC (Personal Computer) on the screen, but also used for home-theater at home.

1 and 2, a typical LCD projector separates light emitted from a casing (not shown) forming an accommodating space therein and a lamp (not shown) accommodated inside one side of the casing. An illumination system 15 to be disposed on one side of the illumination system 15 along the optical path and separated from the illumination system 15 to synthesize the incident light, and a synthesis system 19 arranged on one side of the synthesis system 19 It is composed of a projection lens 25 that allows light to be projected with an appropriate size to an external screen (not shown).

With the above configuration, the driving unit of the projector using the LCD display element is composed of the high brightness lamp and the illumination system 15, which are light sources, through which light is separated into R (Red), G (Green), and B (Blue), respectively. Allows you to adjust the amount of light for your color.

In such a driving unit, contrast and gamma adjustment are made in consideration of factors such as R, G, and B panel characteristics of the display element and human visual characteristics.

The output end of the driving unit consisting of the light source and the illumination system 15 is composed of the synthesis system 19 and the projection lens 25, the synthesis system 19 is a trichromatic light of R, G, B separated from the illumination system 15 The three liquid crystal panels 21a to 21c disposed at right angles to each other and the prism 23 arranged to have a square shape in the front region of the liquid crystal panels 21a to 21c according to each optical path. It is configured to include.

The projection lenses 25 may include a plurality of lenses 27 spaced apart from each other along an axial direction of the light projected to one side through the prism 23 of the synthesis system 19, and the plurality of lenses 27. ) Has a barrel portion 29 for receiving and supporting.

By this configuration, the light irradiated from the lamp is separated into trichromatic light having the corresponding path by the illumination system 15, and each light is incident on the corresponding liquid crystal panels 21a to 21c of the synthesis system 19 through different paths. do. The incident light is projected to one side by the prism 23 and synthesized and projected to the outside through the projection lens 25.

Usually, the projection lens 25 uses a zoom lens so that the size of the screen and the focal length can be adjusted. The zoom lens is composed of three lenses 27 and each lens 27 has a focal length and a screen size. It is fixed through a lens fixing screw (not shown) installed to protrude outward so as to be movable to vary.

In the above-described projector, when the user changes the screen size through a predetermined menu, the focal length is changed by varying the distance between the lenses 27 to adjust the screen size set by the user, wherein the screen size is enlarged or reduced. In this case, the amount of light per unit area changes so that not only changes in contrast but also gamma characteristics change.

That is, in the related art, as the screen size increases, the luminance of the projector decreases, and the contrast also greatly decreases due to the Stevens Effects.

In addition, since the gamma of the adjusted R, G, and B is also changed due to the lowering of the contrast, the deterioration of the image quality of the final image cannot be prevented.

Accordingly, an object of the present invention is to solve the problems of the prior art described above, and an object of the present invention is to adjust a contrast and gamma data according to a screen size so as to realize an optimal screen and a projector screen correction apparatus. To provide a method.

1 is a perspective view showing a conventional projector configuration

Figure 2 is a plan sectional view showing a projection lens of the prior art

Figure 3 is a block diagram showing a screen correction apparatus of the projector according to the present invention

4 is a flowchart illustrating a screen correction method of a projector according to the present invention.

Explanation of symbols for main parts of the drawings

100: control unit 110: distance measuring sensor

120: memory unit 130: contrast adjustment unit

140: gamma adjusting unit 150: driving unit

According to an aspect of the present invention, there is provided a screen correcting apparatus for a projector including a zoom lens configured to include a plurality of lenses to project a screen having a predetermined size onto an external screen. A contrast adjusting unit having a distance measuring sensor for detecting a distance, a memory unit for storing contrast adjustment data and gamma adjustment data according to the magnification of the zoom lens, and contrast adjustment data for adjusting the contrast of the screen projected on the screen; A gamma adjustment unit having gamma adjustment data for adjusting the gamma characteristic of the screen projected on the screen, and calculating a magnification of the zoom lens according to the distance between the zoom lenses detected by the distance measuring sensor and communicating the data with the memory unit to calculate the calculation The contrast adjustment unit according to the magnification of the zoom lens And a control unit for controlling to reset the gamma adjustment data of the contrast adjustment data and the gamma adjustment unit, and a driver for adjusting the contrast and gamma characteristics of the screen according to the reset data of the contrast and the gamma adjustment unit. .

In addition, the screen correction method of the projector according to the present invention for achieving the above object comprises a zoom lens for projecting a screen of a predetermined size on the external screen consisting of a plurality of lenses, a contrast adjustment unit and a gamma adjustment unit A control method of a projector, comprising: initializing contrast adjustment data of the contrast adjustment unit and gamma adjustment data of the gamma adjustment unit when system power is turned on; Resetting the contrast or gamma adjustment data according to the size of the adjusted screen when the user adjusts the size of the screen projected on the screen; And correcting the contrast and gamma characteristics of the screen projected on the screen according to the reset contrast or gamma adjustment data.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, an apparatus and a method of calibrating a screen of a projector according to the present invention will be described with reference to the accompanying drawings.

3 is a block diagram illustrating a screen correction apparatus for a projector according to the present invention, and FIG. 4 is a flowchart illustrating a screen correction method for a projector according to the present invention.

First, the screen correction apparatus of the projector according to the present invention will be described with reference to FIG. 3.

The screen correction apparatus of the projector according to the present invention, as shown in the projector having a zoom lens (not shown) consisting of a plurality of lenses to project a screen of a predetermined size on an external screen (not shown) (not shown) A distance sensor 110 for detecting a distance between the zoom lenses, a memory unit 120 for storing contrast adjustment data and gamma adjustment data according to the magnification of the zoom lens, and contrast of a screen projected on the screen. Contrast adjustment unit 130 having contrast adjustment data for adjustment, gamma adjustment unit 140 having gamma adjustment data for adjusting gamma characteristics of the screen projected on the screen, and a zoom lens sensed by the distance measuring sensor 110 The magnification of the zoom lens is calculated according to the distance therebetween, and the data is communicated with the memory unit 120 to determine the magnification of the zoom lens. The control unit 100 controls to reset the contrast adjustment data of the contrast adjustment unit 130 and the gamma adjustment data of the gamma adjustment unit 140, and the screen according to the adjustment data of the reset contrast and gamma adjustment units 130 and 140. It comprises a drive unit 150 for adjusting the contrast and gamma characteristics of.

At this time, the drawings showing the overall configuration of the projector and the general operation description are omitted, and the same reference numerals are denoted for the same configuration as the conventional art.

As described above, the driving unit 150 is composed of a lamp, which is a light source, and an illumination system 15, thereby separating light into R (Red), G (Green), and B (Blue) through the light. Adjust the amount of. That is, the driver 150 performs contrast and gamma adjustment of the screen projected on the screen.

The R, G, and B signals separated by the driving unit 150 are synthesized through the synthesis system 19, and the synthesized light is appropriately sized to an external screen through the projection lens 25 formed of a zoom lens 27. To project. At this time, the projection lens 25 is composed of three lenses 27 that can be adjusted to the projected screen size and the focal length of the screen and each lens 27 is a lens fixing screw installed to protrude to the outside (Screw) (Not shown).

When the screen size is changed, each of the lenses 27 is moved to move the position of the screw. The present invention provides a distance measuring sensor 110 at the position of the screw to detect a change in distance between the lenses 27. Attach.

For example, when the three lenses 27 are A, B, and C, respectively, the A, B, or C lenses are positioned at fixed screws so that the distance between A, B, B, and C can be detected. One or more distance measuring sensors 110 are attached.

Looking at the operation of the screen correction apparatus of the projector according to the present invention configured as described above, when the main power (On) to the projector (On), the control unit 100 detects it and contrast adjustment data of the contrast adjustment unit 130 And the gamma adjustment data of the gamma adjustment unit 140 are initialized.

An image processor (not shown) of the projector is configured to display an image signal input through an external input means such as a PC (not shown) on the screen, and the processed image signal is driven by the driver 150. Will output

The driver 150 receives the image signal output from the image processor and outputs the R, G, and B tricolor signals to have contrast and gamma characteristics corresponding to the initialized contrast adjustment data and gamma adjustment data.

The trichromatic light signals of R, G, and B output from the driving unit 150 are synthesized through the synthesis system 19, and the synthesized light is projected onto an external screen with an appropriate size through the projection lens 25 to implement a screen. .

In this case, the controller 100 reads the distance between the zoom lenses 27 detected by the distance measuring sensor 110 when a predetermined time interval or a user inputs a screen size adjustment command through a predetermined menu.

Then, the magnification of the current zoom lens 27 is calculated from the distance between the zoom lenses 27 read from the distance measuring sensor 110, and the corresponding contrast adjustment data is calculated according to the calculated magnification of the zoom lens 27. And gamma adjustment data are read from the memory unit 120.

In this case, the memory unit 120 stores the contrast adjustment data and the gamma adjustment data according to the magnification of the zoom lens 27 in a table.

For example, if the magnification of the zoom lens 27 is 1 to 1.3 and the contrast variable region is 50 to 80, the contrast adjustment data 50 is matched to the magnification 1, and the contrast adjustment data 80 is matched to the magnification 1.3 to form a table. do. Gamma Adjustment Data Further, the R, G, and B color coordinates (gamma characteristics) are tabulated by experiment according to the magnification of the zoom lens 27.

The control unit 100 resets the table value of the contrast adjustment unit 130 with the contrast adjustment data read from the memory unit 120, and similarly, the table value of the gamma adjustment unit 130 with the read gamma adjustment data. Reset it.

After resetting the contrast and gamma adjustment data according to the magnification of the zoom lens 27, the driver 150 transmits a signal input from the image processing unit according to the adjustment data of the contrast and gamma adjustment units 130 and 140. And gamma correction to output tricolor light of R, G, and B.

Referring to the screen correction method of the projector according to the present invention configured as described above, as shown in Figure 4 when the system power is turned on (On), that is, the corresponding adjustment data of the contrast adjustment unit and gamma adjustment unit (130, 140), namely contrast Initialize the adjustment data and gamma adjustment data (S100 to S110).

In addition, it is determined whether there is a change in distance between the zoom lenses 27 through the distance measuring sensor 110 (S120).

As a result of the determination (S120), if there is no change in distance between the zoom lenses 27, the initialized contrast adjustment data and gamma adjustment data are maintained, and the screen displayed on the screen is the contrast adjustment unit and the gamma adjustment unit 130 and 140. Output to have a contrast and gamma characteristics corresponding to the current data of (S130).

On the other hand, if there is a change in the distance between the zoom lens 27, the determination result (S120), the lens magnification change is calculated through the distance between the zoom lens 27 (S140).

Then, the contrast adjustment data corresponding to the current lens magnification is read and the adjustment data of the contrast adjustment unit 130 is reset (S150).

At this time, it is determined whether the calculated lens magnification change exceeds a set value (S160). That is, when the amount of change in magnification is greater than a predetermined threshold (Threshold) to a certain degree of change is detected.

As a result of the determination (S160), if the lens magnification change is less than or equal to the set threshold value, the current adjustment data set in the gamma adjusting unit 140 is maintained (S170).

Contrast adjusts the adjustment data of the contrast adjustment unit 130 by continuously changing the value with respect to the lens magnification change, but correction for gamma does not occur continuously and is corrected when the change in magnification is more than the threshold value.

This is to save the storage space of the memory unit 120 because gamma adjustment data occupies a relatively large storage space of the memory unit 120. If the capacity of the memory unit 120 is sufficient, correction of the gamma is also performed. It can be done continuously.

In other words, when the lens magnification is less than or equal to the set threshold value, only the contrast adjustment data is reset and the gamma adjustment data is maintained at the current value to perform screen correction.

If the lens magnification change is greater than or equal to the set threshold, the determination result (S170) reads gamma adjustment data corresponding to the current lens magnification and resets the adjustment data of the gamma adjustment unit 150 (S180).

If the lens magnification change is greater than or equal to the set threshold value, the adjustment data of the contrast adjusting unit and the gamma adjusting units 130 and 140 are reset, and the screen correction is performed according to the reset contrast adjusting data and the gamma adjusting data (S190).

In general, viewers tend to make black and white gradation distinction by setting gamma large when the ambient luminance becomes dark. Since the brightness of the screen itself and the ambient brightness are relative to each other, increasing the magnification of the zoom lens 27 lowers the brightness of the screen itself, which means that the ambient brightness becomes bright. In this case, when one gamma curve is used, an area capable of expressing brightness is narrowed. Therefore, in order to widen the area, it is preferable to move the gamma curve (color coordinate) closer to the Y axis (Luminance axis) by reducing the gamma value.

With this simple theory, when the lens magnification increases only when the change in the zoom lens magnification exceeds the threshold, the gamma adjustment data value is reduced to move the entire gamma curve closer to the Y axis, and conversely, when the lens magnification decreases, the gamma adjustment data is reversed. Increase the value to move it closer to the X axis (input voltage axis).

Therefore, through experiments, the magnification of the entire zoom lens 27 is divided into predetermined steps, an optimal gamma correction curve is obtained for each step, and the gamma correction data for each step is stored in a table in the memory unit 120. do.

The present invention automatically corrects the contrast and gamma characteristics according to the magnification change of the zoom lens 27, that is, the screen size, in order to realize an optimal screen in enlarging / reducing the screen size using the zoom lens.

The screen correction apparatus and method of the projector according to the present invention as described above, when the screen size of the projector is enlarged or reduced in size, the optimum screen is realized by automatically correcting the contrast and gamma characteristics according to the magnification of the zoom lens. There is an effect that can be maximized.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (3)

In the projector having a zoom lens consisting of a plurality of lenses to project a screen of a predetermined size on the external screen, Distance measuring sensor for detecting the distance between the zoom lens, A memory unit for storing contrast adjustment data and gamma adjustment data according to the magnification of the zoom lens; A contrast adjustment unit having contrast adjustment data for adjusting the contrast of the screen projected on the screen, A gamma adjustment unit having gamma adjustment data for adjusting a gamma characteristic of a screen projected on the screen, The magnification of the zoom lens is calculated according to the distance between the zoom lenses detected by the distance measuring sensor, and the data is communicated with the memory to communicate the contrast adjustment data and the gamma adjustment data of the contrast adjustment part according to the calculated magnification of the zoom lens. A control unit for controlling to reset the And a driving unit for adjusting the contrast and gamma characteristics of the screen according to the adjusted data of the contrast and gamma adjustment unit. In the projector control method comprising a zoom lens consisting of a plurality of lenses to project a screen of a predetermined size on an external screen, and a contrast adjustment unit and a gamma adjustment unit, Initializing contrast adjustment data of the contrast adjustment unit and gamma adjustment data of the gamma adjustment unit when system power is turned on; Resetting the contrast or gamma adjustment data according to the size of the adjusted screen when the user adjusts the size of the screen projected on the screen; And, Correcting the contrast and gamma characteristics of the screen projected on the screen according to the reset contrast or gamma adjustment data. The method of claim 2, When the user adjusts the size of the screen projected on the screen, resetting the contrast or gamma adjustment data according to the size of the adjusted screen may be performed. Determining whether there is a change in distance between the zoom lenses according to a user's screen size adjustment command; Calculating a change in magnification of the zoom lens based on a change in distance between the zoom lenses if there is a change in distance between the zoom lenses; Resetting adjustment data of the contrast adjusting unit to contrast adjustment data corresponding to the magnification of the zoom lens when the calculated magnification change of the zoom lens is within a preset range; And resetting adjustment data of the contrast adjusting unit and the gamma adjusting unit with contrast adjustment data and gamma adjustment data corresponding to the magnification of the zoom lens when the calculated magnification change of the zoom lens is greater than or equal to the set range. How to calibrate the projector's screen.