CN104065901B - projection system, projector and correction method thereof - Google Patents

Abstract

The present invention discloses a projection system, a projector and a correction method thereof, wherein: an uncorrected digital driving level output unit enables the projector to project images to at least a part of the area of the projected object at different uncorrected digital driving levels. A brightness sensing device can sense the brightness parameters of the above-mentioned area when the projector is at different uncorrected digital driving levels. A characteristic curve calculation unit can obtain a characteristic curve of the projector according to the uncorrected digital driving level and the brightness parameter. A correction unit can perform a correction procedure according to the characteristic curve and a grayscale standard display function to obtain a corrected digital driving level corresponding to each uncorrected digital driving level. A corrected digital driving level output unit enables the projector to project another image to at least a part of the area of the projected object at the corrected digital driving level.

Description

Projection system, projector and calibration method thereof

technical field

The present invention relates to a projector, and in particular to a projection system, a projector and a calibration method thereof.

Background technique

Since the medical display device is used for disease diagnosis, which is critical to the safety of life, the medical display device must accurately display all the details of the medical image to avoid misjudgment by medical personnel.

In order to help all medical display devices to accurately display all the details of the image, manufacturers and scholars in related fields jointly formulated the Digital Imaging and Communications in Medicine (DICOM) agreement, and formulated in this agreement The grayscale standard display function (Grayscale Standard Display Function, GSDF) is formulated to standardize the conditions that medical images should meet, such as image brightness and so on.

As long as it is used to display medical images, any display device, for example: liquid crystal display, image tube display, etc., must meet the specifications of the grayscale standard display function. However, it is not easy to use a projector to project an image that conforms to the grayscale standard display function.

Contents of the invention

In view of this, an object of the present invention is to enable a projector to project an image conforming to a grayscale standard display function (GSDF).

In order to achieve the above object, according to an embodiment of the present invention, a projection system includes a projector, an uncorrected digital drive level output unit, a brightness sensing device, a characteristic curve calculation unit, a calibration unit, and a Correct the digital drive level output unit. The uncorrected digital driving level output unit can be used to enable the projector to respectively project a picture to at least a partial area of a projected object under different uncorrected digital driving levels (DDL). The brightness sensing device can be used to sense a brightness parameter of the at least partial area when the projector is under different uncorrected digital driving levels respectively. The characteristic curve calculation unit can be used to obtain a characteristic curve of the projector according to the uncorrected digital driving level and brightness parameters. The calibration unit can be used to perform a calibration procedure according to the characteristic curve and the grayscale standard display function, so as to obtain a corrected digital driving level corresponding to each uncorrected digital driving level. The corrected digital driving level output unit is used to enable the projector to project another picture to at least a partial area of the projected object under the corrected digital driving level.

According to another embodiment of the present invention, a projector includes an image projection module, an uncorrected digital driving level output unit, a characteristic curve calculation unit, a calibration unit, and a corrected digital driving level output unit. The uncorrected digital driving level output unit can enable the image projection module to respectively project a picture to at least a partial area of a projected object under different uncorrected digital driving levels. The characteristic curve calculation unit can be used to obtain a characteristic curve of the projector according to the uncorrected digital driving level and a brightness parameter sensed by a brightness sensing device. The calibration unit can be used to perform a calibration procedure according to the characteristic curve and a grayscale standard display function, so as to obtain a corrected digital driving level corresponding to each uncorrected digital driving level. The corrected digital driving level output unit is used to enable the image projection module to project another image to at least a partial area of the projected object under the corrected digital driving level.

According to yet another embodiment of the present invention, the steps of a calibration method for a projector include: when a projector is under different uncorrected digital drive levels, respectively project a picture to at least a partial area of a projected object; When the projectors are under different uncorrected digital drive levels, use a brightness sensing device to sense a brightness parameter of at least part of the area to obtain a characteristic curve of the projector; display according to the characteristic curve and gray scale standard The function performs a correction process to obtain a corrected digital drive level corresponding to each uncorrected digital drive level. Make the projector project another picture to at least a partial area of the object to be projected under the calibrated digital driving level.

In the above embodiments, the brightness parameter sensed by the brightness sensing device is not only related to the projected picture projected by the projector, but also related to the ambient brightness. In this way, the projector can calibrate the digital driving level in consideration of the ambient brightness, so that the projector can project a picture or image conforming to the grayscale standard display function under the calibrated digital driving level.

The above descriptions are only used to illustrate the problems to be solved by the present invention, the technical means for solving the problems, and the effects thereof, etc. The specific details of the present invention will be introduced in detail in the following embodiments and related drawings.

Description of drawings

In order to make the above and other objects, features, advantages and embodiments of the present invention more obvious and understandable, the accompanying drawings are described as follows:

FIG. 1 shows a schematic diagram of a projection system according to an embodiment of the present invention;

FIG. 2 shows a functional block diagram of a projection system according to an embodiment of the present invention;

FIG. 3 shows a graph of a grayscale standard display function according to an embodiment of the present invention;

FIG. 4 shows a graph of a characteristic curve C2 and a curve C1 of a grayscale standard display function according to an embodiment of the present invention;

FIG. 5 shows a hardware architecture diagram of a projection system according to an embodiment of the present invention;

FIG. 6 shows a schematic diagram of a projection system according to another embodiment of the present invention;

FIG. 7 shows a functional block diagram of a projection system according to another embodiment of the present invention;

FIG. 8 shows a flowchart of a calibration method for a projector according to an embodiment of the present invention;

FIG. 9 shows a flow chart of pre-operations of a calibration method for a projector according to an embodiment of the present invention;

FIG. 10 is a flow chart of the post-processing of the projector calibration method according to an embodiment of the present invention.

Wherein, the reference signs are explained as follows:

100: Projector

110: Controller

111, 510: Uncorrected digital drive level output unit

112, 520: characteristic curve output unit

113, 530: correction unit

114, 540: grayscale standard display function storage unit

115, 550: screen fixed unit

116, 560: brightness calculation unit

117, 570: Corrected digital drive level output unit

120: Video signal front-end circuit

130: Video signal processing chip

140: Image projection module

142: display panel

144: rear lens group

146: Front lens group

148: Projection light source

150: Image transmission interface

160: Lighter circuit

170: memory

190: bus

200: Brightness sensing device

300: projected object

310: area

400: connecting line

410: The first sub-connection line

420: The second sub-connection line

500: computer

610～640,701～708,711～717: steps

700: Pre-work

710: post job

C1: Curve of grayscale standard display function

C2: characteristic curve

Lmin: minimum brightness value

Lmax: the highest brightness value

i, j, k, l: points

P1: Sensing data

P2: Calculate data

detailed description

A plurality of embodiments of the present invention will be disclosed in the following figures. For the sake of clarity, many practical details will be described together in the following description. However, those skilled in the art should appreciate that in some embodiments of the present invention, these practical details are not necessary and thus should not be used to limit the present invention. In addition, for the sake of simplifying the drawings, some conventional structures and elements will be shown in a simple and schematic manner in the drawings.

FIG. 1 is a schematic diagram of a projection system according to an embodiment of the present invention. As shown in FIG. 1 , the projection system of this embodiment may include a projector 100 . The projector 100 can project images toward at least a partial area 310 of a projected object 300 . However, the brightness of the image projected by the projector 100 on the projected object 300 is easily affected by the ambient brightness. For example, when the projected object 300 is under sunlight, the image brightness is relatively high. When indoors, the picture brightness is low. Therefore, as long as the ambient brightness changes, it is difficult for the projector 100 to comply with the specifications on Characteristic Curve, Display Function and Grayscale Standard Display Function (GSDF) in the Digital Imaging and Communications for Medical Use (DICOM) protocol. In view of this, the projection system of this embodiment adopts a brightness sensing device 200, which can be electrically connected to the projector 100 wirelessly or wiredly (for example, through the connection line 400), so that the projector 100 can A picture or image conforming to the grayscale standard display function is projected.

Further, please refer to FIG. 2 , which shows a functional block diagram of a projection system according to an embodiment of the present invention. As shown in FIG. 2 , the projector 100 may include an image projection module 140 and a controller 110 electrically connected to the image projection module 140 . The controller 110 may include an uncorrected digital driving level output unit 111 , a characteristic curve calculation unit 112 , a calibration unit 113 , a gray scale standard display function storage unit 114 and a corrected digital driving level output unit 117 . The uncorrected digital drive level output unit 111 of the controller 110 is electrically connected to the image projection module 140 of the projector 100, and can be used to make the image projection module 140 respectively project a The picture reaches at least a partial area 310 of the projected object 300 (see FIG. 1 ). The brightness sensing device 200 can be used to sense a brightness parameter of at least part of the region 310 when the projector 100 is under different uncorrected digital driving levels. The characteristic curve calculation unit 112 is electrically connected to the brightness sensing device 200 and can be used to obtain a characteristic curve (Characteristic Curve) of the projector 100 according to the uncorrected digital driving level and the corresponding brightness parameter. The grayscale standard display function storage unit 114 stores grayscale standard display functions. The calibration unit 113 is electrically connected to the characteristic curve calculation unit 112 and the gray scale standard display function storage unit 114, and can obtain the characteristic curve and the gray scale standard display function from the characteristic curve calculation unit 112 and the gray scale standard display function storage unit 114 respectively, And according to this, a calibration procedure is performed to obtain a corrected digital driving level corresponding to each uncorrected digital driving level. The corrected digital drive level output unit 117 is electrically connected to the correction unit 113 and the image projection module 140, so that the corrected digital drive level can be obtained from the correction unit 113, so that the image projection module 140 can be adjusted at the corrected digital drive level Next, the corrected image is projected to the area 310 of the projected object 300 . In this way, the projector 100 can project images or images conforming to the grayscale standard display function (GSDF) while considering the ambient brightness.

It should be understood that the "uncorrected" digital driving levels and "corrected" digital driving levels described throughout this specification are only used to help readers distinguish between the two digital driving levels before correction and after correction. The digital driving level is a digital signal value, such as an 8-bit digital signal, that is, 0≦DDL≦255, and DDL is an integer.

FIG. 3 is a graph showing a grayscale standard display function according to an embodiment of the present invention. The horizontal axis of this figure is the index of the smallest difference that can be noticed (Just-Noticeable Difference index, JNDindex), and the vertical axis is the luminance parameter in logarithmic form. This luminance parameter in this figure is the luminance value (Luminance, the unit is cd/ m2). The JND described in this manual refers to the brightness difference that the human eye can just feel, and the JND index is the input value of the gray scale standard display function, so the JND index can be substituted into the gray scale standard display function to calculate the brightness parameter. The brightness difference obtained after substituting the JND index and the previous JND index into the grayscale standard display function is just the smallest difference that can be noticed by the human eye. Among them, the grayscale standard display function is as follows:

Where L(j) is the brightness value, j is the JND index, 1≦j≦1023, and j is an integer;

Ln is natural logarithm;

a=-1.3011877, b=-2.5840191E-2, c=8.0242636E-2, d=-1.0320229E-1, e=1.3646699E-1, f=2.8745620E-2, g=-2.5468404E-2, h=-3.1978977E-3, k=1.2992634E-4, m=1.3635334E-4.

FIG. 4 is a graph showing a characteristic curve C2 and a curve C1 of a grayscale standard display function according to an embodiment of the present invention. The horizontal axis of this figure is the digital driving level (DDL), and the vertical axis is the brightness parameter, which is the brightness value in this figure. Different digital driving levels can drive the projector 100 to project pictures with different brightness parameters. For example, when the digital driving level is 70, the brightness value obtained by the brightness sensing device 200 (see FIG. 2 ) can be about 2.15cd/m2; The luminance value obtained by the device 200 may be about 15.9 cd/m2. The above numerical values are examples only, and are not intended to limit the present invention.

According to the digital driving level and the brightness parameter sensed by the brightness sensing device 200, the characteristic curve calculation unit 112 can generate the characteristic curve C2. For example, referring to FIG. 2 and FIG. 4, the brightness sensing device 200 can sense and obtain a plurality of sensing data P1, and the characteristic curve calculation unit 112 can use an interpolation method to calculate the After obtaining the calculation data P2, the characteristic curve calculation unit 112 can synthesize the sensing data P1 and the calculation data P2 to generate the characteristic curve C2.

Referring to FIGS. 2 , 3 and 4 , the luminance values obtained by the luminance sensing device 200 under different digital driving levels are between the minimum luminance value Lmin and the maximum luminance value Lmax. Based on this, the calibration unit 113 can obtain the gray scale standard display function curve C1 between the lowest brightness value Lmin and the highest brightness value Lmax in FIG. 3 .

According to the curve C1 and the characteristic curve C2 of the grayscale standard display function, the calibration unit 113 can correct the digital driving level. Specifically, as shown in FIG. 2 and FIG. 4, the uncorrected driving level can be point i, and the correction unit 113 can obtain the corresponding first brightness parameter on the curve C1 of the gray scale standard display function, that is, point i j. The correction unit 113 can obtain a second brightness parameter equal to the first brightness parameter on the characteristic curve C2, that is, a point k equal to the point j. The correction unit 113 can obtain the corrected digital driving level corresponding to point k from the characteristic curve C2 , that is, point l.

Since the correction unit 113 can obtain the corrected digital driving level corresponding to each uncorrected digital driving level according to the curve C1 and the characteristic curve C2 of the grayscale standard display function, these uncorrected digital driving levels (such as points i) and the corrected digital driving level (such as point l) are made into a look-up table (Look-up Table, LUT). In this way, when the image projection module 140 (refer to FIG. 2 ) receives an uncorrected digital driving level DDL_i, it only needs to find the corresponding uncorrected digital driving level DDL_i from the look-up table in the correction unit 113. Correct the digital driving level DDL_1, and then provide the corrected digital driving level DDL_1 to the image projection module 140 through the corrected digital driving level output unit 117, so that the image projection module 140 can project a picture conforming to the gray scale standard display function or image. In addition, since the existing image projection module 140 is equipped with a LUT for the digital drive level of the video signal, the above-mentioned corrected digital drive level output unit 117 can also be stored and implemented in the image projection module in practice. 140 in.

In addition to ambient brightness, when the size of the screen changes, the brightness of the screen may also change accordingly. For example, when the image is zoomed out, its brightness may increase, and conversely, when the image is enlarged, its brightness may decrease. Therefore, in some embodiments, as shown in FIG. 2 , the projection system may further include a frame fixing unit 115, which can be used to control the image projection module 140 to fix the size of the frame, so as to avoid affecting the brightness sensed by the brightness sensing device 200. brightness parameter.

In some implementations, when the screen size changes, the screen fixing unit 115 can control the image projection module 140 to fix the changed screen size after the size change is completed. After the frame size is fixed, the brightness parameter can be re-sensed by the brightness sensing device 200 , and the characteristic curve C2 (refer to FIG. 4 ) can be re-obtained by the characteristic curve calculation unit 112 , and re-calibrated by the calibration unit 113 . In this way, even if the screen size changes, the projector 100 can still project a screen or image conforming to the grayscale standard display function.

In addition to ambient brightness and screen size, the gain value of the projected object 300 (refer to FIG. 1 ) may also affect the brightness parameter sensed by the brightness sensing device 200 . Therefore, in some implementations, as shown in FIG. 2 , the projection system may further include a brightness calculation unit 116 . The brightness parameter sensed by the brightness sensing device 200 can be an illuminance value (Illuminance, the unit is lux), and the brightness calculation unit 116 can receive the data of the illuminance value, and calculate according to the illuminance value and the gain value ( Gain) to get the brightness value of the screen (Luminance, the unit is cd/m2). Specifically, when the brightness sensing device 200 senses the illuminance value I, the brightness calculation unit 116 may execute the following formula to obtain the brightness value L:

I×r/π=L

Among them, π is the circumference ratio, that is, π=3.1415926...;

r is the reflectance of the projected object 300 .

Generally speaking, the reflectivity r of the projected object 300 is approximately equal to its gain value, or is positively correlated with the gain value. Therefore, according to the above formula, the brightness value L can be obtained according to the gain value (reflectance) and the illuminance value I. Therefore, the projector 100 can project a frame or image conforming to the grayscale standard display function by considering the gain value through the calculation of the brightness calculation unit 116 . Preferably, the gain value of the projected object 300 is 1, and its reflectivity r is also 1.

FIG. 5 shows a hardware architecture diagram of a projection system according to an embodiment of the present invention. As shown in Figure 5, the projector 100 may include a controller 110, a video signal front-end circuit 120, a video signal processing chip 130, an image projection module 140, an image transmission interface 150, a lamp circuit 160, a memory 170 and a bus 190 . The controller 110 , the video signal front-end circuit 120 and the video signal processing chip 130 are all electrically connected to the bus 190 , and the image projection module 140 is electrically connected to the video signal processing chip 130 . In this way, the controller 110 can control the image projection module 140 to project images through the video signal front-end circuit 120 and the video signal processing chip 130 .

Please refer to FIG. 5 , in some embodiments, the controller 110 can be controlled by an external device through the remote sensor 102 , or through the connection interface 104 . The remote sensor 102 can be an infrared sensor, but the present invention is not limited thereto. The connection interface 104 can be an RS232 interface, but the invention is not limited thereto. Please also refer to FIG. 2, the uncorrected digital drive level output unit 111, the characteristic curve calculation unit 112, the correction unit 113, the gray scale standard display function storage unit 114, the picture fixing unit 115, the brightness calculation unit 116 and the corrected digital drive circuit. The flat output unit 117 can be disposed in the controller 110 of the projector 100 . For example, the above units can be programs, software or firmware installed in the controller 110, but the present invention is not limited thereto.

During the calibration process, the controller 110 can control the video signal processing chip 130 to output full-white images with different brightness according to different uncorrected digital driving levels, so as to facilitate calibration. After the calibration is completed, the controller 110 can control the video signal processing chip 130 to output a picture conforming to the grayscale standard display function according to the corrected digital driving level.

In some implementations, an external device (such as a mobile phone, a video signal generator, a notebook computer, etc.) can transmit images to the video signal front-end circuit 120 through the video transmission interface 150 . The video signal front-end circuit 120 can convert the image into a form suitable for the image projection module 140 . For example, the video signal front-end circuit 120 can convert the picture in analog form to the picture in digital form. During the calibration process, the image transmitted by the external device to the video signal front-end circuit 120 may be a full white image.

In some implementations, the video signal processing chip 130 can receive the picture from the video signal front-end circuit 120 and can adjust the quality of the picture. For example, the video signal processing chip 130 can adjust the image resolution or color saturation, etc., but the invention is not limited thereto. In some implementations, the memory 170 can be used as a buffer memory required by the video signal processing chip 130 for signal processing (eg, resolution adjustment).

In some implementations, the video signal processing chip 130 does not need to receive the picture transmitted by the video signal front-end circuit 120 , but can provide the picture by itself. For example, the video signal processing chip 130 can generate monochrome or full white images with specified brightness by itself.

In some implementations, the image projection module 140 can project the image transmitted by the video signal processing chip 130 to the projected object 300 . Specifically, the image projection module 140 may include a display panel 142 , a rear lens 144 group, a front lens group 146 and a projection light source 148 . The front lens group 146 , the display panel 142 and the rear lens group 144 are sequentially disposed on the optical path of the light emitted by the projection light source 148 . The projection light source 148 is electrically connected to the lighter circuit 160 . The display panel 142 is electrically connected to the video signal processing chip 130 and can receive images transmitted by the video signal processing chip 130 . When the lighter circuit 160 is turned on, the projection light source 148 will emit light, and the light will pass through the front lens group 146, the display panel 142 and the rear lens group 144 in order to project the image on the display panel 142 to the projected object 300 superior.

In some implementations, the brightness sensing device 200 may be a photometer (photometer or light-meter) or a photo-sensor (photo-sensor), etc., but the invention is not limited thereto. In some implementations, the projected object 300 can be a curtain or a wall, etc., but the present invention is not limited thereto.

FIG. 6 is a schematic diagram of a projection system according to another embodiment of the present invention. As shown in FIG. 6 , the main difference between this embodiment and FIG. 1 is that this embodiment may also include a computer 500 . The computer 500 is electrically connected between the projector 100 and the brightness sensing device 200 . Specifically, the computer 500 can connect to the projector 100 through the first sub-connection line 410 , and connect to the brightness sensing device 200 through the second sub-connection line 420 . The first sub-connection cable 410 has the same specifications as the connection interface 104 (see FIG. 3 ) of the projector 100 , so the computer 500 can connect to and control the projector 100 through the connection interface 104 .

FIG. 7 is a functional block diagram of a projection system according to another embodiment of the present invention. As shown in Figure 7, the function of the computer 500 is similar to that of the controller 110 in Figure 2, which may include an uncorrected digital drive level output unit 510, a characteristic curve calculation unit 520, a correction unit 530, and a gray scale standard display function storage unit 540 , a frame fixing unit 550 , a brightness calculation unit 560 and a corrected digital driving level output unit 570 . That is to say, the functions executable by the computer 500 are the same as those of the controller 110 in FIG. 2 and related descriptions above, so the descriptions will not be repeated here. The above units may be programs, software or firmware installed in the computer 500, but the present invention is not limited thereto. In this embodiment, since the calibration program is executed by the computer 500, the burden on the projector 100 can be reduced.

In some embodiments, the computer 500 can be a desktop computer, a notebook computer, a tablet computer, a smart phone or a personal digital assistant (PDA), etc., but the present invention is not limited thereto.

FIG. 8 is a flow chart of a calibration method for a projector according to an embodiment of the present invention. As shown in Figure 8, the correction method of this embodiment may include the following steps:

In step 610 , when the projector is at different uncorrected digital driving levels, respectively project images to at least partial areas of the object to be projected. Specifically, the projector can project pictures with different brightness to the projected object according to different uncorrected digital driving levels.

In step 620, when the projectors are under different uncorrected digital driving levels, a brightness sensor is used to sense a brightness parameter of at least part of the region, so as to obtain a characteristic curve of the projector. Specifically, when the uncorrected digital driving levels of the projector change, the brightness sensing device can be used to sense the brightness parameters on the projected object, and then according to all the uncorrected digital driving levels and their corresponding brightness parameters, Create a characteristic curve.

In step 630, a calibration procedure can be performed according to the characteristic curve and the gray scale standard display function to obtain the corrected digital driving level corresponding to each uncorrected digital driving level, and these uncorrected digital driving levels can be converted into And the corrected digital driving level is made into a look-up table (Look-up Table, LUT).

In step 640, the projector can be made to project another picture to the at least partial area of the object to be projected under the calibrated digital driving level.

The specific calibration method can be referred to FIG. 9 and FIG. 10. FIG. 9 shows a flowchart of the pre-operation 700 of the projector calibration method according to an embodiment of the present invention, and FIG. 10 shows a projector according to an embodiment of the present invention. A flow chart of post-operation 710 of the calibration method. As shown in FIG. 9, the pre-work 700 includes the following steps:

In step 701 , the pre-operation 700 is started.

In step 702, the frame size is fixed. Specifically, the screen size can be adjusted to a desired size first, and then the screen fixing unit in the projector or an external computer can be used to control the image projection module to fix the screen size.

In step 703, the minimum value of the uncorrected digital drive level may be provided. Specifically, the uncorrected digital driving level output unit may output the minimum value of the uncorrected digital driving level to the image projection module.

In step 704, the brightness parameter at the uncorrected digital drive level may be sensed and stored. Specifically, the brightness parameter of the picture on the projected object can be sensed or sensed by the brightness sensing device.

In step 705, the uncorrected digital drive level may be increased. Specifically, the uncorrected digital drive level can be increased by one unit by the uncorrected drive level output unit. For example, if the form of the digital driving level is 8 bits, then the digital driving level DDL can satisfy: 0≦DDL≦255, and DDL is an integer, and in step 705, the digital driving level of one unit can be increased , such as changing from 0 to 1.

In step 706, it may be checked whether the uncorrected digital drive level is less than a maximum value. Specifically, the uncorrected digital drive level output unit can check whether the uncorrected digital drive level output by it is less than the maximum value, for example, if the form of the digital drive level is 8 bits, it can be checked whether it is less than 255 . If the digital driving level is less than the maximum value (for example: 255), return to step 704; if the digital driving level is equal to the maximum value (for example: 255), then enter step 707.

In step 707, the maximum value and the minimum value of the sensed brightness parameter can be retrieved. Specifically, the maximum value and minimum value of the brightness parameter can be obtained by the characteristic curve calculation unit, and all the brightness parameters and uncorrected digital driving levels in this interval can be made into the characteristic curve C2 (refer to FIG. 4 ).

In step 708, the segment between the maximum value and the minimum value corresponding to the above-mentioned brightness parameter in the grayscale standard display function is obtained. Specifically, the calibration unit can obtain the gray scale standard display function curve C1 (refer to FIG. 4 ) from the gray scale standard display function storage unit, and obtain the section between the maximum value and the minimum value of the brightness parameter.

After the pre-operation 700 is completed, the characteristic curve C2 and the curve C1 of the grayscale standard display function can be obtained. Then you can enter the post-operation 710, as shown in Figure 10, the post-operation 710 includes the following steps:

In step 711, the minimum value of the uncorrected digital drive level may be provided. Specifically, the uncorrected digital driving level output unit may output the minimum value of the uncorrected digital driving level to the correction unit.

In step 712, a first luminance parameter on the curve C1 corresponding to the gray scale standard display function corresponding to the uncorrected digital driving level in step 711 can be obtained. For example, referring to FIG. 4 , the uncorrected driving level may be point i on the graph, and its first luminance parameter on the curve C1 of the grayscale standard display function is point j.

In step 713, a second brightness parameter equal to the first brightness parameter is obtained on the characteristic curve C2, and a corrected digital driving level corresponding to the second brightness parameter is obtained and recorded from the characteristic curve C2. For example, referring to FIG. 4 , the calibration unit can obtain point k on the characteristic curve C2 that is equal to point j, and then obtain point l on the graph of the corrected digital driving level from point k.

In step 714, the uncorrected digital drive level may be increased. Specifically, the uncorrected digital drive level can be increased by one unit by the uncorrected drive level output unit. For example, if the form of the digital driving level is 8 bits, then the digital driving level DDL can satisfy: 0≦DDL≦255, and DDL is an integer, and in step 705, the digital driving level of one unit can be increased , such as changing from 0 to 1.

In step 715, it may be checked whether the uncorrected digital drive level is less than a maximum value. Specifically, the uncorrected digital drive level output unit can check whether the uncorrected digital drive level output by it is less than the maximum value, for example, if the form of the digital drive level is 8 bits, it can be checked whether it is less than 255 . If the digital drive level is less than the maximum value (for example: 255), then return to step 712; if the digital drive level is equal to the maximum value (for example: 255), then enter step 716.

In step 716, a look-up table recording the uncorrected digital drive levels and the corrected digital drive levels may be stored. Specifically, the correction unit can store each uncorrected digital drive level (such as point i in Figure 4) and its corresponding corrected digital drive level (such as point l in Figure 4), and make a lookup surface.

In step 717, the flow of the calibration method ends.

After the pre-operation 700 and the post-operation 710 are completed, the corrected digital drive level output unit can output the corrected digital drive level to the image projection module, so that the image projection module can project a picture conforming to the gray scale standard display function or image.

Although the present invention has been disclosed above in terms of implementation, it is not intended to limit the present invention. Anyone skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall prevail as defined in the scope of the appended patent application.

Claims (11)

1. a kind of optical projection system, comprising：

One projector；

One does not correct digital driving levels output unit, to make the projector not corrected under digital driving levels in different, At least part region of a picture a to projectual is projected respectively；

One brightness sensing device, to when the projector respectively in described do not correct under digital driving levels when, sense this at least One luminance parameter of subregion；

One characteristic curve computing unit, not correct digital driving levels and the luminance parameter according to, obtains the throwing One characteristic curve of shadow machine；

One correction unit, it is every to obtain to carry out a correction program according to the characteristic curve and a GTG standard display function One corresponding to digital driving levels is not corrected described in one and has corrected digital driving levels；And

One has corrected digital driving levels output unit, to make the projector in the case where this has corrected digital driving levels, projection Another picture is at least part region of the projectual；

One picture fixed cell, to fix the size of the picture, and makes the characteristic curve computing unit in the size of the picture The characteristic curve under fixation, is obtained, and makes the correction unit in the case where the size of the picture is fixed, the correction journey is carried out Sequence.

2. optical projection system as claimed in claim 1, the wherein correction program performed by the correction unit are included：

There is provided and do not correct digital driving levels described in one；

Obtain this and do not correct digital driving levels correspondence to one first luminance parameter on the GTG standard display function；

One second luminance parameter equal with first luminance parameter is obtained on the characteristic curve；And

Digital driving levels have been corrected as this corresponding to the characteristic curve obtains second luminance parameter.

3. optical projection system as claimed in claim 1, in addition to：

The luminance parameter that one luminance calculation unit, the wherein brightness sensing device are sensed is a brightness value, the brightness calculation Unit is used to the yield value according to the brightness value and at least part region, obtains a brightness value of the picture.

4. optical projection system as claimed in claim 1, wherein this does not correct digital driving levels output unit, the characteristic curve meter Calculate unit and the correction unit is arranged in the projector.

5. optical projection system as claimed in claim 1, in addition to：

One computer, is electrically connected with the projector, and wherein this does not correct digital driving levels output unit, the characteristic curve and calculates single Member and the correction unit are arranged in the computer.

6. a kind of projector, comprising：

One image projection module；

One does not correct digital driving levels output unit, and digital drive electricity is not corrected to make the image projection module different Under flat, at least part region of a picture a to projectual is projected respectively；

One characteristic curve computing unit, is sensed not correct digital driving levels according to a brightness sensing device A luminance parameter, obtain a characteristic curve of the projector；And

One correction unit, it is every to obtain to carry out a correction program according to the characteristic curve and a GTG standard display function One corresponding to digital driving levels is not corrected described in one and has corrected digital driving levels；

One has corrected digital driving levels output unit, and digital driving levels have been corrected to make the image projection module at this Under, another picture is projected at least part region of the projectual；And

One picture fixed cell, to fix the size of the picture, and makes the characteristic curve computing unit in the size of the picture The characteristic curve under fixation, is obtained, and makes the correction unit in the case where the size of the picture is fixed, the correction journey is carried out Sequence.

7. projector as claimed in claim 6, the wherein correction program performed by the correction unit include：

There is provided and do not correct digital driving levels described in one；

Obtain this and do not correct digital driving levels correspondence to one first luminance parameter on the GTG standard display function；

One second luminance parameter equal with first luminance parameter is obtained on the characteristic curve；

Digital driving levels have been corrected as this corresponding to the characteristic curve obtains second luminance parameter.

8. projector as claimed in claim 6, in addition to：

The luminance parameter that one luminance calculation unit, the wherein brightness sensing device are sensed is a brightness value, the brightness calculation Unit is used to the yield value according to the brightness value and at least part region, obtains a brightness value of the picture.

9. a kind of bearing calibration of projector, its step is included：

When not correcting under digital driving levels, a picture a to projectual is projected respectively at least different by a projector Subregion；

When the projector respectively in described do not correct under digital driving levels when, sense at least portion using a brightness sensing device A subregional luminance parameter, to obtain a characteristic curve of the projector；

One correction program is carried out according to the characteristic curve and a GTG standard display function, to obtain each described not correcting numeral One corresponding to drive level has corrected digital driving levels；And

Make the projector in the case where this has corrected digital driving levels, project another picture at least part area of the projectual Domain,

Wherein in the case where the size of the picture is fixed, obtain the characteristic curve and carry out the correction program,

Wherein described bearing calibration also includes：After the size of the picture changes, retrieve the characteristic curve and re-start The correction program.

10. the bearing calibration of projector as claimed in claim 9, the wherein correction program are included：

There is provided and do not correct digital driving levels described in one；

This is obtained not correct corresponding to digital driving levels to one first luminance parameter on the GTG standard display function；

One second luminance parameter equal with first luminance parameter is obtained on the characteristic curve；And

Digital driving levels have been corrected as this corresponding to the characteristic curve obtains second luminance parameter.

11. the bearing calibration of projector as claimed in claim 9, the wherein luminance parameter are a brightness value, and the correction side Method also includes the yield value according to the brightness value and at least part region, obtains a brightness value of the picture.