TW201737701A - System and method for adjusting projection brightness and contrast - Google Patents

Abstract

One embodiment of the invention discloses a system and method for adjusting projection brightness and contrast. A system for adjusting projection brightness and contrast includes an image pickup unit, a brightness measurement unit, a distance measurement unit, a brightness adjustment unit, and a contrast adjustment unit.

Description

Automatic adjustment system and method for projection brightness and contrast

The invention relates to an automatic adjustment system for projection brightness and contrast and an automatic adjustment method for projection brightness and contrast.

If the projector continues to project a high-brightness screen, it will easily reduce the life of the light source and prevent heat dissipation. Generally speaking, if the brightness difference between the screen brightness and the background brightness of the projector is too small, the picture will be too dark and the color will be poor. However, when the difference between the brightness of the projector screen and the background brightness is too large, the eyes will be easily uncomfortable when viewing the screen. When the brightness of the screen and the background brightness are at an appropriate ratio, the visual effect is better and the human eye is more comfortable. Therefore, the projector often has a need to adjust the projection brightness in real time. However, current projector brightness is manually adjusted and is inconvenient.

The invention provides an automatic adjustment system for projection brightness and contrast and an automatic adjustment method for projection brightness and contrast.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein. In order to achieve one or a portion or all of the above or other objects, an embodiment of the present invention provides an automatic adjustment system for projection brightness and contrast. The automatic adjustment system for projecting brightness and contrast comprises an image capturing unit, a brightness measuring unit, a ranging unit, a brightness adjusting unit and a contrast adjusting unit. The image capturing unit captures an image to obtain brightness of a background area outside the projection area or the projection area, and the brightness measuring unit calculates an ambient brightness value according to the image capturing parameter of the image capturing unit and the lens characteristic parameter of the projector. . The ranging unit is based on the projector's AF position and The lens characteristic parameter calculates a focusing distance, and the brightness adjusting unit calculates an output luminous intensity value according to the focusing distance, the ambient brightness value and a brightness increasing magnification, wherein the brightness increasing magnification is a preset comfort brightness value and an ambient brightness value. The ratio, and the projector adjusts the brightness projected onto the projection area based on the output illumination intensity value. The contrast adjustment unit sets an output contrast value with reference brightness increase magnification, and the projector adjusts the contrast of the projection area according to the output contrast value.

According to the design of the above embodiment, the projector can automatically adjust the brightness or contrast required by the screen according to the current ambient brightness, improve the flexibility and convenience of the brightness adjustment of the screen, and can automatically adjust the brightness or contrast of the projector. Avoid continuous use of high-brightness projection screens, thus extending lamp life and reducing heat dissipation requirements.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein. The above and other objects, features, and advantages of the invention will be apparent from

10‧‧‧Automatic adjustment system for projection brightness and contrast

12‧‧‧Image capture unit

14‧‧‧Brightness measurement unit

16‧‧‧Ranging unit

18‧‧‧Brightness adjustment unit

19‧‧‧Contrast adjustment unit

21‧‧‧Auto Focus Unit

22‧‧‧Projector

22a‧‧‧ lens

23‧‧‧ Processor

24‧‧‧ camera

24a‧‧‧Image lens

24b‧‧‧Photosensor

25‧‧‧Light source driver

26‧‧‧Image

27‧‧‧Image Processor

28‧‧‧Image Processing Unit

29‧‧‧Processor

32‧‧‧ screen

A‧‧‧projection area

B‧‧‧Background area

C‧‧‧ contrast value

F‧‧‧Brightness correction factor

I‧‧‧ images

L‧‧‧Focus distance

N‧‧‧ brightness increase magnification

O‧‧‧Output luminous intensity value

S‧‧‧Environmental brightness value

S1, S2‧‧‧Gamma curve

1 is a block diagram showing an automatic adjustment system for projection brightness and contrast according to an embodiment of the present invention.

2 and 3 are schematic views illustrating an example of the constitution of a component of the automatic adjustment system of Fig. 1.

4 is a schematic diagram showing a relative position of an image capturing area and a projected area according to an embodiment of the present invention.

Fig. 5 is a schematic view showing an example of calculating an output luminous intensity value from the focusing distance.

Figure 6 is a diagram illustrating the adjustment of contrast by setting different gamma curves.

FIG. 7 is a flowchart of a method for automatically adjusting projection brightness and contrast according to an embodiment of the present invention.

FIG. 8 is a flowchart of a method for automatically adjusting projection brightness and contrast according to another embodiment of the present invention.

FIG. 9 is a flowchart of a method for automatically adjusting projection brightness and contrast according to another embodiment of the present invention.

FIG. 10 is a schematic diagram showing a relative position of an image capturing area and a projected area according to another embodiment of the present invention.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the embodiments of the invention. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only directions referring to the additional drawings. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

1 is a schematic diagram of an automatic adjustment system for projection brightness and contrast according to an embodiment of the present invention. The automatic adjustment system 10 for projecting brightness and contrast can automatically adjust the brightness or contrast required of the projected picture according to the brightness of the surrounding environment, so that the observer can view a projection picture that is more comfortable with respect to the human eye. As shown in FIG. 1 , the automatic brightness adjustment system 10 for projecting brightness and contrast may include an image capturing unit 12 , a brightness measuring unit 14 , a ranging unit 16 , a brightness adjusting unit 18 , and a contrast adjusting unit 19 . The image capturing unit 12 can capture an image I to obtain the brightness of a background area or a background area outside the projection area, and the brightness measuring unit 14 can according to the image capturing parameters of the image capturing unit 12 and the lens characteristics of the projector. The parameter calculates an ambient brightness value S. The ranging unit 16 can calculate a focusing distance L according to the AF position and the lens characteristic parameter of the projector 22, and the brightness adjusting unit 18 can calculate according to the focusing distance L, the ambient brightness value S, and a brightness increasing magnification N. An output luminous intensity value O is obtained, and the brightness increasing magnification N is a ratio of a preset comfort brightness value to an ambient brightness value S, and the projector 22 can adjust the brightness projected to the projection area according to the output luminous intensity value O. The contrast adjustment unit 19 can set an output contrast value C with reference to the brightness increase magnification N, and the projector 22 adjusts the contrast of the projection area according to the output contrast value C. As shown in FIG. 2, in an embodiment, the projector 22 can have an auto-focusing unit 21 and have an auto-focusing function, and can project an image onto the object such as the screen 32 via the lens 22a. The image capturing unit 12 can be, for example, For a camera 24 as shown in FIG. 3, the camera 24 can be disposed on the projector 22, for example, but is not limited. The ranging unit 16 and the brightness adjusting unit 18 can be, for example, a processor 23, and the processor 23 can provide calculations. The function of the focus distance L, the brightness increase magnification N, and the output illumination intensity value O, the brightness adjustment unit 18 can be, for example, the light source driver 25 of the projector 22, and the light source driver 25 can adjust the illumination intensity according to the output illumination intensity value O, thereby changing the projection. The brightness to the projection area. The processor 23 can be provided, for example, in the auto-focus unit 21 or other device without limitation. The contrast adjustment unit 19 can be, for example, an image processor 27 of the projector 22, and the image processor 27 can adjust the Gamma curve of the output brightness according to the set output contrast value C. As shown in FIG. 3, the camera 24 may include, for example, an image taking lens 24a for collecting optical signals and a light sensor 24b for converting optical signals into electronic signals. The electronic signals are then subjected to subsequent image processing by the image processing unit 28. Camera 24 and image processing unit 28 may be, for example, components in a camera. In one embodiment, the brightness measurement unit 14 can be a processor 29 in the image processing unit 28, and the processor 29 can calculate the ambient brightness value S according to the image taking parameters of the camera 24 and the lens characteristic parameters of the projector 22.

As shown in FIG. 4, the projector 22 can form a projection area A on the screen 32, and the camera 24 can capture an image 26 that is larger than the projection area A. Therefore, the area of the image 26 outside the projection area A can be regarded as In the background area B, when the camera 24 captures the image 26, the brightness of the projection area A or the background area B can be obtained. The measuring unit 14 can calculate an environment according to the image taking parameters of the camera 24 (such as exposure time, brightness gain value and gray scale bit value) and the lens characteristic parameters of the projector 22 (for example, the projected picture size, the lens focus length, etc.). Brightness value S. Furthermore, the ranging unit 16 can calculate a focus distance L according to the auto focus position and the lens characteristic parameter of the projector 22 (ie, the linear distance of the lens to the projected picture after the projector completes autofocus). An example of obtaining a focus distance L between the projector lens 22a and the screen 32 by the autofocus function of the projector 22 will be described below. As shown in the following table, assuming that the projector 22 has completed the position correction of the 30-inch picture, the number of motor steps required to obtain the position corresponding to an absolute reference point is 200 steps. When the projector 22 completes the auto-focus, the lens 22a moves to The number of motor steps required for the current position is 124 steps. Since the position of the projection screen 32 is unchanged, the focusing distance can be 2629 mm from the table below. Furthermore, if the actual number of motor steps does not appear in the table below, the focus distance can be obtained by interpolation or by additionally creating a table of the number of steps corresponding to each step.

The preset comfort brightness value required for the projected picture can be set to N times the ambient brightness value S (N>1), that is, when the ambient brightness value S is measured, the brightness of the projected picture is adjusted to N times the ambient brightness value. A picture with comfortable brightness can be obtained, and the N value can be defined as a brightness increase magnification. Therefore, in an embodiment, if the projector has the ability to project N times the brightness value, an output illuminance required by the projector light source can be calculated according to the focus distance L, the ambient brightness value S, and the brightness increase magnification N. The intensity value O is used to instantly adjust the brightness projected onto the projection area A. In an embodiment, the output luminous intensity value O output by the light source driver 25 of the projector 22 can be obtained by the following formula: Output luminous intensity value O (lm) = ambient brightness value (lm / m ² ) × brightness gain ratio N × projection area area (m ² ) = ambient brightness value S (lm / m ² ) × brightness increase magnification N × focus distance L (m) × tan θ v × (2 × focus distance L (m) × tan θ _H ); The definition of the parameters in the formula is as shown in Fig. 5, where θ _H is the horizontal angle of the projection area A with respect to the optical axis, and tan θ _V is the vertical angle of the projection picture with respect to the optical axis.

In an embodiment, when the light source of the projector 22 cannot reach the capability of projecting N times the brightness value, the contrast adjusting unit 19 can select the Gamma curve S1 for enhancing the output contrast as shown in FIG. 6 to compensate for the lack of brightness enhancement. For better projection picture quality. In another embodiment, the contrast gamma curve may be adjusted first, and then the brightness gain magnification N may be increased, so that a good picture with a small brightness gain ratio N can be obtained, thereby saving power consumption of the light source. In another embodiment, it is also conceivable to simultaneously adjust the contrast gamma curve (for example, the selection curve S1 to strengthen the contrast or the curve S2 to weaken the contrast) and the brightness gain ratio N to obtain a good picture quality while achieving energy saving effects.

For example, if the brightness gain ratio N is set to 5-7 times, Gamma can be selected by the table value in the range of 25-75% to obtain good picture quality and achieve energy saving effect. In this embodiment, the table value can be determined according to the formula: for example, [Nn, Gn]=[(7-0.2n), (25+5n)].

In another embodiment, as shown in the following table, the table value can be directly determined from the empirical value or demand according to the formula:

In an embodiment, as shown in FIG. 7, an automatic adjustment method of projection brightness and contrast may include the following steps:

Step S102: Turn on the system.

Step S104: Capture an image by using an image capturing unit to obtain brightness of a background area outside the projection area or the projection area.

Step S106: Calculate an ambient brightness value according to the image capturing parameter of the image capturing unit and the lens characteristic parameter of the projector.

Step S108: Perform an autofocus operation of the projector.

Step S110: According to the focus position and lens characteristic of the projector The number calculates a focus distance.

Step S112: Calculate an output brightness value according to the focus distance and the ambient brightness value, and the projector adjusts the brightness and contrast projected to the projection area according to the output brightness value and the brightness gain magnification. Furthermore, the output brightness and the contrast can be adjusted in real time according to the ambient brightness change (step S116). If the ambient brightness changes, the process can be repeated by repeating the above process to adjust the brightness and contrast of the projected picture, and if not, the end is The sub-adjustment process, in which the "end" term represents the end of the adjustment process and waits for the next environmental change to be adjusted (step S118).

As shown in FIG. 8, in another embodiment, an automatic adjustment method of projection brightness and contrast may include the following steps:

Step S202: Turn on the system.

Step S204: Perform an autofocus operation of the projector.

Step S206: Capture an image by using an image capturing unit to obtain brightness of a background area outside the projection area or the projection area.

Step S208: Calculate an ambient brightness value according to the image capturing parameter of the image capturing unit and the lens characteristic parameter of the projector.

Step S210: Calculate a focus distance according to the auto focus position and the lens characteristic parameter of the projector.

Step S212: Calculate an output brightness value according to the focus distance and the ambient brightness value, and the projector adjusts the brightness and contrast projected to the projection area according to the output brightness value and the brightness gain magnification. Furthermore, for example, when the projector moves or other factors have the need to refocus (step S216), the process may be repeated by step S204 to repeat the above process to adjust the brightness and contrast of the projected screen. If no adjustment is needed, the adjustment process is ended. Here, the term "end" means that the current adjustment process is ended and the system waits for the next environmental change to be adjusted (step S218).

The brightness adjustment process shown in FIG. 7 and FIG. 8 is only an example and is not limited. In other embodiments, for example, the autofocus of the projector and the operation of capturing images by the image capturing unit may be performed simultaneously. In addition, although FIG. 7 and FIG. 8 show the adjustment process of adjusting the brightness and contrast of the projection area at the same time, it is not limited, and various factors (such as projector light-emitting capability, energy-saving efficiency, and screen quality requirements) may be used. Adjust the brightness of the projected area or adjust only the contrast of the projected area. Furthermore, the contrast adjustment process of the aforementioned projection area can be implemented regardless of whether the projector 22 adopts an auto focus or a manual focus mode.

In summary, the embodiment of the present invention has at least one of the following advantages: by the design of the above various embodiments, the projector can automatically adjust the brightness or contrast required for the picture according to the current ambient brightness, and improve the maneuver of the brightness adjustment of the picture. Sexuality and convenience, and through the automatic adjustment of the brightness or contrast of the projector, the continuous use of high-brightness projection images can be avoided, thus extending the life of the light source and reducing the heat dissipation requirement.

As shown in FIG. 9, in another embodiment, an automatic adjustment method of projection brightness may include the following steps:

Step S302: Turn on the system.

Step S304: Perform an autofocus operation of the projector.

Step S306: Capture an image by using an image capturing unit to obtain brightness of the projection area and a background area outside the projection area.

Step S308: Calculate an ambient brightness value according to the image capturing parameter of the image capturing unit and the lens characteristic parameter of the projector.

Step S310: determining whether the brightness of the projection area is weighted by a brightness correction factor, and whether the preset comfort brightness is reached. In an embodiment, the preset comfort brightness value may be N times the ambient brightness value (=ambient brightness value (lm/m ² )×N), and the brightness correction factor F may be the total number of pixels of the projected picture divided by The sum of the brightness values of all the pixels, so when the current projection brightness value (lm/m ² ) multiplied by the brightness correction factor F is not equal to the preset comfort brightness value, the brightness of the projector is increased or decreased ( Step S312) and skipping to step S306 to repeat the above process until the weighting value is equal to the preset comfort brightness value, ending the adjustment process, where the "end" term represents the system that ends the adjustment process and waits for the next environmental change. Adjustment is further made (step S314).

With the design of the embodiment, the effect of automatic adjustment of the projection brightness and contrast can be obtained without calculating the focusing distance.

As shown in FIG. 10, in an embodiment, if the image 26 captured by the image capturing unit 12 has a smaller range than the projection area A of the projector 22, the black screen may be inserted during projection or measured when not projected to obtain a background. Brightness, also can be calculated according to the focus distance and ambient brightness value.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the terms "first" and "second" as used in the specification or the scope of the claims are only used to name the components or distinguish different embodiments or ranges, and are not intended to limit the upper or lower limits of the number of components. .

10‧‧‧Automatic adjustment system for projection brightness and contrast

12‧‧‧Image capture unit

14‧‧‧Brightness measurement unit

16‧‧‧Ranging unit

18‧‧‧Brightness adjustment unit

19‧‧‧Contrast adjustment unit

22‧‧‧Projector

Claims (13)

An automatic adjustment system for projecting brightness and contrast, comprising: an image capturing unit, capturing an image to obtain brightness of a projection area or a background area outside the projection area; and a brightness measuring unit for capturing the image according to the image The image capturing parameter of the unit and the lens characteristic parameter of the projector calculate an ambient brightness value; a ranging unit calculates a focusing distance according to an autofocus position of the projector and the lens characteristic parameter; a brightness adjusting unit, Calculating an output luminous intensity value according to the focusing distance, the ambient brightness value, and a brightness increasing magnification, wherein the brightness increasing magnification is a ratio of a preset comfort brightness value to the ambient brightness value, and the projector is configured according to the The output luminous intensity value adjusts the brightness projected to the projection area; and a contrast adjusting unit sets an output contrast value with reference to the brightness increasing magnification, and the projector adjusts the contrast of the projected area according to the output contrast value. An automatic adjustment system for projecting brightness and contrast for adjusting brightness and contrast of a projection area of a projector with an autofocus function, the automatic adjustment system for brightness and contrast of the projection includes: a camera capturing an image to obtain The brightness of the projection area or a background area outside the projection area; a first processor calculates an ambient brightness value according to the image taking parameter of the camera and the lens characteristic parameter of the projector; and a second processor calculates the image according to an auto focus position of the projector and the lens characteristic parameter a focusing distance, calculating a brightness increasing magnification according to the ambient brightness value and a preset comfort brightness value, calculating an output luminous intensity value according to the focusing distance and the brightness increasing magnification, and referring to the brightness increasing magnification setting An output contrast value; a light source driver that adjusts brightness projected to the projection area according to the output illumination intensity value; and an image processor that adjusts contrast of the projection area according to the output contrast value. An automatic adjustment system for projected brightness and contrast as described in claim 1 or 2, wherein the image taking parameter comprises an exposure time, a brightness gain value, and a gray scale bit value. An automatic adjustment system for projecting brightness and contrast as claimed in claim 1 or 2, wherein the lens characteristic parameter comprises a projected picture size and a lens focus length. An automatic adjustment system for projecting brightness and contrast as described in claim 1 or 2, wherein the number of steps of the motor path required to move to the focus position corresponds to the focus distance. An automatic adjustment system for projecting brightness and contrast as described in claim 2, wherein the camera comprises an image taking lens for collecting the light signal and a light sensor for converting the light signal into an electronic signal. An automatic adjustment method for projection brightness and contrast for adjusting a projector projection The brightness and contrast of a projected area of the projection, the automatic adjustment method of the brightness and contrast of the projection includes: capturing an image by using an image capturing unit to obtain brightness of the projection area or a background area outside the projection area; Calculating an ambient brightness value according to the image capturing parameter of the image capturing unit and the lens characteristic parameter of the projector; calculating a focusing distance according to the AF position of the projector and the lens characteristic parameter; and according to the focusing distance and the environment The brightness value calculates an output luminous intensity value and an output contrast value, and the projector respectively adjusts the brightness and contrast projected to the projection area according to the output luminous intensity value and the output contrast value. The method for automatically adjusting the brightness and contrast of the projection according to claim 7 further includes: re-capturing the image according to the ambient brightness change to instantly adjust the brightness and contrast of the projected area. The method for automatically adjusting the brightness and contrast of the projection according to claim 7 further includes: changing the auto focus position of the projector and retrieving the image to instantly adjust the brightness of the projection area. An automatic brightness adjustment method for adjusting a brightness of a projection area projected by a projector, the method for automatically adjusting the brightness of the projection includes: Obtaining an image by using an image capturing unit to obtain brightness of a projection area or a background area outside the projection area; calculating an ambient brightness according to the image capturing parameter of the image capturing unit and the lens characteristic parameter of the projector Calculating a focus distance according to the AF position of the projector and the lens characteristic parameter; and calculating an output light intensity value according to the focus distance and the ambient brightness value, and the projector adjusts according to the output light intensity value The brightness projected to the projection area. An automatic brightness adjustment method for adjusting a brightness of a projection area projected by a projector, the method for automatically adjusting the brightness and contrast of the projection includes: capturing an image by using an image capturing unit to obtain the projection area and the The brightness of a background area outside the projection area; calculating an ambient brightness value according to the image capturing parameter of the image capturing unit and the lens characteristic parameter of the projector; comparing the brightness of the projected area by a brightness correction factor weighting calculation The weighting value and a preset comfort brightness value; and adjusting the output brightness of the projector such that the weighting value is equal to the comfort brightness value. An automatic adjustment method for projection brightness and contrast as described in claim 11, wherein the comfort brightness value is a multiple of the ambient brightness value. An automatic adjustment method for projection contrast, comprising: capturing an image by using an image capturing unit to obtain brightness of a projection area or a background area outside the projection area; according to the image capturing parameter of the image capturing unit and the projection Calculating an ambient brightness value according to the lens characteristic parameter of the machine; calculating a focus distance according to a focus position of the projector and the lens characteristic parameter; calculating a brightness increase ratio according to the ambient brightness value and a preset comfort brightness value Setting an output contrast value with reference to the brightness increase magnification; and adjusting the contrast of the projection area according to the output contrast value.