TWI771131B - Parameter adjusting method and projector - Google Patents

Abstract

A parameter adjusting method is applied to a projector having an ambient light sensor, a database and a digital micromirror device. The parameter adjusting method includes analyzing a detection signal generated by the ambient light sensor to acquire an environmental light datum, comparing the detection signal with a lookup table of the database to compute at least one compensation parameter, and adjusting an amount of reflection light generated by the digital micromirror device in accordance with the at least one compensation parameter for controlling the projector to output a calibrated projecting image in response to compensation of the environmental light datum.

Description

Parameter adjustment method and its projector

The present invention provides a method for adjusting parameters and a projector thereof, especially a method for adjusting parameters and a projector for automatically correcting a projected image according to ambient light information.

Generally speaking, projectors have been widely used in conference presentations, advertisement placement, exhibition performances and other places. They use a lens system to generate a wide range of projection images. The projector can provide the most original picture color performance in a non-illuminated environment; however, in some lighting environments, the projected picture will be affected by the ambient light information, resulting in color fade and blurred details. In order to overcome this problem, users usually try to reduce the brightness of the ambient light, but it is difficult to reduce to a no-light environment. Another solution is to increase the brightness of the light source of the projector. However, the increase of the projection brightness will increase the projector's energy consumption, body temperature, fan speed, mechanical noise, and equipment cost. After the brightness of the light source is increased, it cannot be calculated and the color change of the preset projection screen needs to be tested one by one to know the conversion relationship between the color change and the increased brightness of the light source. The test process is cumbersome and the accuracy rate is low. Therefore, how to design a parameter adjustment method and a projector that can quickly and correctly adjust the projection image in response to ambient light information is a key development goal of the related optical system design industry.

The present invention provides a parameter adjustment method and a projector for automatically correcting a projected image according to ambient light information, so as to solve the above-mentioned problems.

The scope of the patent application of the present invention is to disclose a parameter adjustment method, which is applied to a projector having an ambient light detector, a database and a digital micro-mirror module. The parameter adjustment method includes acquiring a detection signal generated by the ambient light detector to obtain ambient light information, comparing the detection signal with a look-up table in the database to calculate at least one compensation parameter, and calculating at least one compensation parameter according to the At least one compensation parameter adjusts the amount of reflected light of the digital micro-mirror module, so as to control the projector to project a modified projection image which is compensated according to the ambient light information.

The scope of the patent application of the present invention further discloses that the parameter adjustment method further includes selecting a key color chip, obtaining a reference color parameter of the key color chip when the brightness of an environment where the projector is located is lower than a threshold value, and measuring An original color parameter of the key color chip under the ambient light information, and the difference between the reference color parameter and the original color parameter is compared to establish the look-up table. A color gamut coordinate system of one of the key color chips is located within a color gamut range of one of the original color parameters. The ambient brightness being lower than the threshold value means that the projector is in a no-illuminated light situation.

The scope of the patent application of the present invention further discloses a projector with a parameter adjustment function, which includes an ambient light detector, a database, a digital micromirror module and an arithmetic processor. The ambient light detector is used for generating a detection signal to obtain ambient light information. The database is used to store a look-up table. The arithmetic processor is electrically connected to the ambient light detector, the database and the digital micromirror module. The arithmetic processor is used for obtaining the ambient light information, comparing the detection signal with a look-up table in the database to calculate at least one compensation parameter, and adjusting a reflection of the digital micromirror module according to the at least one compensation parameter The amount of light is controlled, thereby controlling the projector to project a modified projection image which is compensated according to the ambient light information.

The parameter adjustment method and the projector of the present invention firstly establish a look-up table for common light source types and different ambient brightness according to the color coordinate change from high saturation to low saturation of color chips, that is, saturation sweeps. Domain compensation; the feature of the present invention is that it only needs to select a few color chips for adjustment, and then the precise adjustment of the overall projection picture can be completed. Then, compare the ambient light information obtained by the ambient light detector with the look-up table, and then use interpolation or other calculation methods to find the closest parameters, and use the digital micro-mirror module to control the amount of reflected light to adjust the projection screen so that The original color parameters can be close to or overlap with the base color parameters. The parameter adjustment method and the projector of the present invention can effectively achieve the purpose of correcting the projected image without adjusting the projection light source, and have the advantages of energy saving, low operating temperature, low operating noise, low equipment cost, and high color adjustment accuracy .

10: Projector

12: Digital Micromirror Module

14: Ambient light detector

16:Database

18: Computing processor

20: Projection Curtain

22: External light source

24: Solid triangle

26: Dotted triangle

S100, S102, S104, S106, S108, S110, S112, S114: Steps

S200, S202, S204, S206, S208, S210: Steps

FIG. 1 is a functional block diagram of a projector according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of the assembly of the projector according to the embodiment of the present invention.

FIG. 3 is a flowchart of establishing a lookup table according to an embodiment of the present invention.

FIG. 4 is a flowchart of a parameter adjustment method according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of a color space displayed by a parameter adjustment method according to an embodiment of the present invention.

Please refer to FIG. 1. FIG. 1 is a functional block diagram of the projector 10 according to an embodiment of the present invention. The projector 10 may include a digital micromirror module 12 , an ambient light detector 14 , a database 16 and an arithmetic processor 18 . The ambient light detector 14 is used to generate a detection signal to obtain ambient light information, such as analyzing the brightness of the detection signal or other parameters to determine the ambient brightness. Database 16 is used to store lookup tables. The look-up table may be the default information established by the system in the database 16, or may be stored by the projector 10 during autonomous operation during operation The update information in the database 16; the source of the lookup table is not limited to the previously disclosed implementation form, and the end depends on the design requirements. The arithmetic processor 18 can be electrically connected to the digital micromirror module 12 , the ambient light detector 14 and the database 16 . The projector 10 has a parameter adjustment function; the arithmetic processor 18 can automatically adjust the amount of reflected light of the digital micro-mirror module 12 according to the ambient light information of the location of the projector 10 , so that the projected image can maintain the same color under various ambient brightness.

Please refer to FIGS. 2 to 5. FIG. 2 is a schematic diagram of assembling the projector 10 according to an embodiment of the present invention, FIG. 3 is a flowchart of establishing a lookup table according to an embodiment of the present invention, and FIG. 4 is an embodiment of the present invention. The flow chart of the parameter adjustment method of FIG. 5 is a schematic diagram of the color space displayed by the parameter adjustment method according to the embodiment of the present invention. The projector 10 can project a projection image with complete color information on the projection screen 20 in an environment without ambient light; however, in order to meet the user's viewing needs, the projector 10 is usually applied in a place with a slight ambient brightness, and an external light source is used. The ambient light information generated by 22 will affect the quality of the projected image, so the parameter adjustment method of the present invention can correspondingly improve the parameters such as white balance, hue, saturation, gain value and gamma value of the projected image according to the ambient light information, so that after compensation, The projected picture can have better color performance.

Regarding the lookup table establishment method, step S100 is first performed to select key color tickets in the color space. Generally speaking, the key color swatches will choose the three primary colors of light and color, which means red (Red, R), green (Green, G), blue (Blue, B), cyan (Cyan, C), magenta (Magenta, M), Yellow (Yellow, Y). Next, steps S102 and S104 are executed to obtain the reference color parameters of the key color chips when the ambient brightness of the projector 10 is lower than the threshold value, and the original color parameters of the measured key color chips under ambient light information. The definition of the reference color parameters and the original color parameters can be the color coordinates of the key color chips at a specific saturation, such as 20%, 40%, 60%, 80%, 100% saturation. The percentage of saturation and its interval difference are not limited to the previously disclosed implementations, but depend on actual needs.

As shown in FIG. 5 , when the projector 10 is in a non-illuminated light environment, the original color gamut of the projected image is the solid triangle 24 in the color space, and the non-illuminated light environment can also be interpreted as a projector When the brightness of the environment where the projector 10 is located is lower than the threshold value; if the projector 10 is in an environment with illumination light, which means that the brightness of the environment where the projector 10 is located is higher than or equal to the threshold value, the original color gamut ( color gamut) is a dashed triangle 26 in the color space. The color gamut coordinates of the key color chips need to be within the color gamut range of the original color parameters, which means the solid line triangle 24 shown in Figure 5; generally speaking, the color coordinates of the key color chips with 100% saturation may fall on the dotted line Outside the triangle 26, in practice, the color coordinates of 100% saturation are generally not selected. The selection of key color chips and their reference color parameters and original color parameters is not limited to the previous implementation, but depends on actual needs.

Next, step S106 is executed to obtain a plurality of original color luminances of each key color ticket under different ambient light information. The present invention can predict the possible variation range of the ambient brightness, and delimit a plurality of illuminance intervals within the possible variation range; , lux), and can delineate a plurality of illuminance intervals in units of 50 lux. Next, step 108 is executed to list a plurality of original color luminances and the relationship between the corresponding gamma compensation values and saturation compensation values to be included in the look-up table, as shown in Table 1 below.

Next, step S110 is executed to obtain the comparison relationship between a plurality of original color gamut coordinates (i.e. color temperature) and a plurality of light source types for each key color ticket under different ambient light information, and then continue to execute steps S112 and S114, list Figure out the relationship between a plurality of light source types and the corresponding white balance compensation value and hue compensation value to be included in the look-up table, as shown in Table 2 below. It is particularly mentioned that the reference color parameters and the original color parameters can be at least one or two parameters of the color brightness and color gamut coordinates of the corresponding key color chips, which means that Table 1 and Table 2 can be used as look-up tables, Or use the set of Table 1 and Table 2 as the lookup table required for the parameter adjustment method.

After the lookup table is established, it can be applied to the parameter adjustment method of the present invention. First, step S200 is executed to obtain ambient light information by using the detection signal generated by the ambient light detector 14 . Next, step S202 is executed to analyze the detection signal to determine whether the original projection image of the projector 10 is affected by the ambient light information. If the original projected image is not affected by the ambient light information, it means that the ambient brightness is very low, or the brightness of the projection light source of the projector 10 is extremely high and is not disturbed. Therefore, step S204 is executed, and the digital micro-mirror model is not adjusted. The amount of reflected light for group 12. If the original projected image is affected by ambient light information, for example, the ambient brightness is higher than the preset brightness threshold, or the ratio of ambient brightness to the brightness of the projection light source is higher than the preset brightness threshold, steps S206 and S208 can be executed to connect to the data The library 16 obtains the look-up table, and substitutes the detection signal into the look-up table to calculate the compensation parameters. Finally, step S210 is executed to adjust the amount of reflected light of the digital micromirror module 12 according to the compensation parameter, so as to control the projector 10 to project a modified projection image compensated according to the ambient light information.

As shown in FIG. 5, when the brightness of the environment where the projector 10 is located is higher than or equal to the threshold value, the key color swatches (including six colors of red R, green G, blue B, cyan C, magenta M, and yellow Y) The color coordinates of various degrees of saturation are circular marks in the color space, which are located in the dotted triangle 26; and after adjusting the amount of reflected light of the digital micromirror module 12 by the parameter adjustment method of the present invention, the various degrees of saturation of the key color chips are The color coordinates can be respectively corrected as rectangular marks in the color space, which means that the key color chips of various saturation can be corrected to the position close to the solid triangle 24, so that the projected picture provided by the projector 10 in a high ambient brightness can be adjusted. It can have the same or similar to the projected image performance at low ambient brightness.

To sum up, the parameter adjustment method and the projector of the present invention firstly establish common light source types and different ambient brightness according to the color coordinate change from high saturation to low saturation of the color chip, that is, saturation sweeps. The characteristic of the invention is that only a few kinds of color chips are selected for adjustment, and the precise adjustment of the overall projection picture can be completed. Then, compare the ambient light information obtained by the ambient light detector with the look-up table, and then use interpolation or other calculation methods to find the closest parameters, and control the amount of reflected light through the digital micro-mirror module to adjust the whiteness of the projected image Balance (WB, also regarded as color temperature), Hue (Hue), Saturation (Saturation), Gain value (Gain, also regarded as brightness), Gamma value (meaning the smoothness of the transition between black and white blocks), let The original color parameters can be close to or overlap with the base color parameters. Compared with the prior art, the parameter adjustment method and the projector of the present invention do not require Improving the brightness of the projection light source can effectively achieve the purpose of correcting the projection image, and has the advantages of energy saving, low operating temperature, low operating noise, low equipment cost, and high color adjustment accuracy.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

S200, S202, S204, S206, S208, S210: Steps

Claims (11)

A parameter adjustment method is applied to a projector having an ambient light detector, a database and a digital micromirror module. The parameter adjustment method includes: obtaining a detection generated by the ambient light detector signal to obtain ambient light information; select a key color chip and obtain a reference color parameter of the key color chip when an ambient brightness where the projector is located is lower than a threshold value, wherein the ambient brightness is lower than the threshold value A color gamut coordinate of the key color chip is located within a color gamut range of an original color parameter when there is no lighting environment; an original color parameter of the key color chip under the ambient light information is measured, and the reference color parameter is compared The difference from the original color parameter is used to establish a look-up table in the database; the detection signal is compared with the look-up table to calculate at least one compensation parameter; and the digital micromirror module is adjusted according to the at least one compensation parameter. A reflected light quantity is used to control the projector to project a modified projection image which is compensated according to the ambient light information. The parameter adjustment method according to claim 1, wherein a color gamut coordinate system of the key color chip is located within a color gamut range of the original color parameter. The parameter adjustment method as claimed in claim 1, wherein the ambient brightness is lower than the threshold value means that the projector is in a no-illuminated light condition. The parameter adjustment method of claim 1, wherein the reference color parameter and the original color parameter each include at least one of a color gamut coordinate and a color brightness of the key color swatch. The parameter adjustment method as described in claim 1, further comprising: Obtaining a plurality of original color intensities of the key color swatches under different ambient light information; and listing the relationship between the plurality of original color intensities and corresponding gamma compensation values to be included in the look-up table. The parameter adjustment method according to claim 1, further comprising: obtaining a plurality of original color intensities of the key color ticket under different ambient light information; and listing the relationship between the plurality of original color intensities and corresponding saturation compensation values to be included in this lookup table. The parameter adjustment method according to claim 1, further comprising: obtaining a plurality of original color gamut coordinates of the key color chip under different ambient light information and the comparison relationship of different light source types. The parameter adjustment method according to claim 7, further comprising: listing the relationship between the light source types and the corresponding white balance compensation values to be included in the look-up table. The parameter adjustment method according to claim 7, further comprising: listing the relationship between the light source types and the corresponding hue compensation values to be included in the look-up table. The parameter adjustment method according to claim 1, further comprising: analyzing the detection signal to determine whether an original projection image of the projector is affected by the ambient light information; and if the original projection image is affected by the ambient light Affect, connect to the database for comparison of the detected signal with the lookup table. A projector with parameter adjustment function, which includes: an ambient light detector for generating a detection signal to obtain ambient light information; a database for storing a look-up table; a digital micromirror module; and an arithmetic processor electrically connected to the ambient light detector The tester, the database and the digital micromirror module are used to execute the parameter adjustment method described in one of claim 1 to claim 10.

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