JP2003114669A - Image display device, image processing method, program, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device, an image processing method and a program which detect changes of external environment in real time and perform desired image processing. SOLUTION: The image display device which displays an image by performing desired image processing to image input data, measures external environment data by a 1st optical sensor 165 and measures display image data by a 2nd optical sensor 170. Further, external environment change detecting means 180 and 185 detect changes of the external environment according to the external environment data measured by the 1st optical sensor 165. When the changes of the external environment are detected, the 2nd optical sensor 170 measure data of the displayed image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device, an image processing method, a program and a recording medium for detecting an influence of an external environment on an output image and performing desired image processing.

[0002]

2. Description of the Related Art When using an image display device such as a projector, it is important to be able to reproduce an image intended by the manufacturer even if the external environment changes. There is a concept of color management that reproduces colors by managing the input / output characteristics of the device as a concept of adjusting the appearance of such an image, but regarding a concrete method of color management that takes into account changes in the external environment. Is not clear.
In particular, it is difficult to reproduce an appropriate color unless consideration is given to the case where the brightness or color of the external illumination or the color of the projection surface changes as the change of the external environment. Typically,
When the brightness of the external illumination increases, the contrast of the output image of the image display device decreases, and proper color reproduction becomes impossible. Further, for example, even when the same white is displayed, the color may change depending on the color of the external illumination and the type of the projection surface.

In order to grasp such a change in the external environment, a desired patch is output from the image display device to the screen, and the patch displayed on the screen is subjected to color measurement by a sensor.

[0004]

However, when the image display device is projecting an image on the screen,
It is difficult to display the desired patch on the screen, and it is difficult to grasp the change in the external environment in real time and correct it.

The present invention has been made to solve the above-mentioned problems, and an image display device, an image processing method, and an image processing method for detecting a change in the external environment in real time to perform desired image processing.
The challenge is to provide a program.

[0006]

In view of the above-mentioned problems, the invention according to claim 1 is an image display device for performing desired image processing on image input data to display an image, wherein the external environment data A first data measuring means for measuring
A second data measuring means for measuring the data of the displayed image; and an external environment change detecting means for detecting a change in the external environment based on the external environment data measured by the first data measuring means. When the change of the external environment is detected, the data measurement of the displayed image by the second data measuring means is performed.

According to the image display apparatus configured as described above, which displays the image by performing the desired image processing on the image input data, the first environmental data is measured by the first data measuring means, and the second environmental data is measured. The data of the image displayed by the data measuring means is measured. The external environment change detecting means detects a change in the external environment based on the external environment data measured by the first data measuring means, and when the change in the external environment is detected, the second environment is detected.
Data measurement of the displayed image is performed by the data measurement means.

The invention described in claim 2 is the same as claim 1.
The image display device according to claim 2, wherein the first data measuring unit measures the lightness as the external environment data, and when the change amount of the lightness within a predetermined time is equal to or more than a threshold value, the second
It is arranged to make a data measurement of the displayed image by the data measuring means.

Further, the invention according to claim 3 is the image display device according to claim 2, wherein the first data measuring means measures the brightness as the external environment data, and the brightness of the brightness within a predetermined time is measured. When the amount of change is 30 to 50% or more, the data measurement of the displayed image by the second data measurement means is performed.

The invention according to claim 4 is the same as claim 2
Alternatively, the image display device according to the third aspect is configured so that the predetermined time is about 10 seconds or less.

Further, the invention according to claim 5 is the image display device according to any one of claims 1 to 4, wherein the first data measuring means measures the brightness as external environment data, When the measured lightness is equal to or higher than a predetermined value, the data measurement of the displayed image by the second data measuring means is performed.

The invention according to claim 6 is the same as claim 5
The image display device according to 1, wherein the predetermined value is 50 to 10
Configured to be 0 lux.

Further, the invention according to claim 7 is the image display device according to any one of claims 1 to 6, wherein the first data measuring means and the second data measuring means are combined into one unit. Consists of a sensor.

The invention described in claim 8 is the same as claim 1.
7. The image display device according to any one of items 1 to 6,
The first data measuring means and the second data measuring means are constituted by different sensors.

Further, the invention according to claim 9 is an image processing method for image input data input to an image display device, wherein a first data measuring step for measuring external environmental data is displayed. Second to measure image data
A data measuring step and an external environment change detecting step for detecting a change in the external environment based on the external environment data measured in the first data measuring step are provided, and when a change in the external environment is detected, , Is configured to perform data measurement of the displayed image according to the second data measurement step.

According to a tenth aspect of the present invention, there is provided a program for causing a computer to execute image processing on image input data input to an image display device.
A first data measurement process for measuring the external environment data, a second data measurement process for measuring the data of the displayed image, and an external environment data of the external environment based on the external environment data measured by the first data measurement process. A computer is caused to execute an external environment change detection process for detecting a change, and a process of measuring data of a displayed image by the second data measurement process when a change in the external environment is detected. Composed.

Further, the invention according to claim 11 is a computer-readable recording medium in which the program according to claim 10 is recorded.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

First Embodiment System Configuration FIG. 1 shows a projector 2 according to the first embodiment of the present invention.
The schematic explanatory drawing of the image display system using 0 is shown. The image display device of the present invention includes a projector, a CR
T, liquid crystal display, etc. are also included.

A predetermined image is projected from a projector 20 provided almost in front of the screen 10.

In this case, the appearance of the projected image greatly differs depending on the type of the screen 10 and the external illumination 80. For example, even if the same white is displayed, it may appear yellowish white depending on the type of the screen 10. Even when the same white is displayed, it may appear bright or dark depending on the intensity of the external illumination 80.

In the first embodiment, as shown in FIG. 1, the first optical sensor 16 for measuring external environment data is used.
5 and the second optical sensor 170 for measuring the data of the displayed image are separately provided.

FIG. 2 shows a functional block diagram of the image processing section 100 in the projector 20 of the present invention.

Image processing unit 10 in the projector of the present invention
0 is an A / D conversion unit 110 that converts an analog image input signal into a digital signal, and a color correction unit 120 that applies a one-dimensional color correction table to each RGB image input signal to perform desired color correction. A D / A converter 130 for converting a digital signal into an analog signal, an L / V (light valve) driver 140 for driving a liquid crystal light valve to project and display an image, and a dark room A device characteristic storage memory 160 for storing the color characteristic information of the projector when output to the reference projection plane, and a first light for measuring external environment data (brightness as an example in the embodiment). The sensor 165, the second optical sensor 170 for measuring the brightness of the light reflected by the projector and the screen of the external lighting, and the light based on the external environment data from the first optical sensor. Brightness detecting unit 180 for detecting the
And a lightness change detection unit 185 for detecting a lightness change based on the external environment data from the first light sensor, and a colorimetric value of the light sensor 170 and a device characteristic storage device according to the detected lightness / lightness change. And a color correction table generation unit 150 that generates a color correction table in consideration of the influence of external illumination based on the information stored in the memory.

In the projector according to the present invention, an analog image input signal supplied from a personal computer or the like is converted into a digital image signal by the A / D converter 110. Then, the converted digital image signal is referred to the color correction table generated by the color correction table generation unit 150, and is subjected to desired color correction by the color correction unit 120 in consideration of the influence of external illumination.
The color-corrected digital image signal is output to the D / A conversion unit 130.
Is converted into an analog signal by. L / V drive unit 14
0 drives the liquid crystal light valve based on the converted analog signal to project and display an image.

Operation of Image Processing Unit 100 Next, the operation of the image processing unit 100 in the projector 20 of the present invention will be described with reference to FIG. The processing by the image processing unit 100 such as the generation / writing process of the color correction table described below is performed by executing the image processing program recorded in the program storage unit (not shown) of the projector 20. . The program storage unit constitutes a medium recording an image processing program. Furthermore, the image processing program itself is also included within the scope of the present invention.

First, when the use of the projector 20 according to the present invention is started, the color correction table generating section 150 performs a color correction table generating / rewriting process (step 204). The generation / rewriting process of the color correction table will be described in detail below with reference to FIG.

After the color correction table generation / rewriting process, the image is displayed based on the image signal color-corrected by the color correction unit 120 with reference to the rewritten color correction table (step 206). . Here, if the lightness detected by the lightness detection unit 180 is less than a predetermined value (Step 210, No) without displaying the image (No at Step 208), or the lightness detected by the lightness change detection unit 185 is detected. Change less than threshold (step 21
2, No), the display state of the image in step 206 continues. On the other hand, the display of the image is not ended (step 20
8, No), the brightness detected by the brightness detection unit 180 is a predetermined value or more (step 210, Yes), and the brightness change within the predetermined time detected by the brightness change detection unit 185 is the threshold value or more (step 212). , Yes)
In this case, it is judged that the external environment has changed, and in consideration of the case where the brightness or color of the external lighting or the color of the projection surface changes over time, the color correction table is generated and rewritten again. (Step 204), the image is displayed (Step 206).

In this embodiment, as an example, when the brightness change within about 10 seconds is 30 to 50%, it is determined that the brightness change within the predetermined time detected by the brightness change detection unit 185 is equal to or more than the threshold value. Shall be.

Further, in this embodiment, as an example, the brightness detected by the brightness detection unit 180 is 50 to 10
When it is 0 lux or more, it is determined that the brightness detected by the brightness detection unit 180 is a predetermined value or more.

According to the image display device of the first embodiment, the change of the external environment is judged based on the external environment data from the first optical sensor 165, and the external illumination is based on the measured image data from the second optical sensor 170. Since the color correction table is rewritten in consideration of the brightness or the color of the image, or the change of the color of the projection surface, it is possible to appropriately reproduce the color.

When the display of the image is terminated by turning off the power of the projector (step 208, Y)
The processing ends in (es).

Color Correction Table Generation / Rewriting Process Next, referring to FIG. 4, a color correction table generation / rewriting process by the color correction table generation unit 150 in the projector 20 of the present invention (step 204 in FIG. 3). Processing) will be described.

FIG. 4 shows a flowchart for explaining the color correction table generation / rewriting processing according to the present invention.

As shown in FIG. 4, in the color correction table generation / rewriting process, the color correction table generation unit 150
First, the color characteristic data of the device is acquired from the device characteristic storage memory 160 (step 220). That is, the color correction table generation unit 150 outputs the projector output (white, red, green, blue, and black 5) under the reference environment (dark room, reference projection plane) stored in the device characteristic storage memory 160.
Color (color) measured by the second optical sensor 170 (XYZ
Value). Projector output (white red green blue black 5
The measurement data (XYZ value) of color) is defined as follows.

[0036] White (R, G, B) = (255,255,255) X_WO  Y_WO  Z_WO Red (R, G, B) = (255, 0, 0) X_RO  Y_RO  Z_RO Green (R, G, B) = (0,255, 0) X_GO  Y_GO  Z_GO Blue (R, G, B) = (0, 0,255) X_BO  Y_BO  Z_BO Black (R, G, B) = (0, 0, 0) X_KO  Y_KO  Z_KO From RGB based on these measurement data (XYZ values)
The matrix Mo for conversion to XYZ is

[0037]

[Equation 1] Is asked for.

Next, the color correction table generator 150 measures the external environment data (step 222). That is, the color correction table generation unit 150 measures the outputs (five colors of red, green, blue, and black) of the projector under the use environment by the second optical sensor 170. The external environment data is measured by displaying a patch on the edge of the screen. The measurement data (XYZ values) of the projector outputs (five colors of white, red, green, blue and black) under the use environment are defined as follows.

[0039] White (R, G, B) = (255,255,255) X_Wd  Y_Wd  Z_Wd Red (R, G, B) = (255, 0, 0) X_Rd  Y_Rd  Z_Rd Green (R, G, B) = (0,255, 0) X_Gd  Y_Gd  Z_Gd Blue (R, G, B) = (0, 0,255) X_Bd  Y_Bd  Z_Bd Black (R, G, B) = (0, 0, 0) X_Kd  Y_Kd  Z_Kd From RGB based on these measurement data (XYZ values)
The matrix Md for conversion to XYZ is

[0040]

[Equation 2] Is asked for.

Next, the color correction table generator 150
Calculation of correction parameters (parameters of (1) to (3) below) necessary for generating the dimensional color correction table (step 2)
24). (1) Both the white brightness Yw of the projector and the brightness Yi of the illumination are values on the correction target projection surface, and are used in correction for changes in the brightness of the external illumination. Yw = Ywd−Ykd (3) Yi = Ykd (4) (2) to correct for color change of the RGB colors luminance ratio projection plane of the _{projector, y R, y G, y} B (RGB colors luminance ratio of the correction target projection plane) y _R0, y _G0, y _B0 (luminance ratio of each RGB color on the reference projection plane) is used. These values are y _R = (Y _Rd -Y _kd ) / (Y _Gd -Y _kd ) ... (5) y _G = (Y _Gd -Y _kd ) / (Y _Gd -Y _kd ) = 1 ... (5) 6) y _B = (Y _Bd -Y _kd ) / (Y _Gd -Y _kd ) ... (7) y _R0 = (Y _R0 -Y _k0 ) / (Y _G0 -Y _k0 ) ... (8) y _G0 = ( Y _G0 -Y _k0 ) / (Y _G0 -Y _k0 ) = 1 (9) y _B0 = (Y _B0 -Y _k0 ) / (Y _G0 -Y _k0 ) ... (10) (3) Luminance r on the RGB correction target projection surface when the XYZ values of the illumination are expressed by the RGB mixed colors of the projector
i, gi, bi ri, gi, bi are used to correct for changes in the color of the external lighting,

[0042]

[Equation 3] Required by.

A one-dimensional color correction table for each color of RGB is generated by using the parameters for correcting each influence obtained as described above (step 230).

Generation of One-Dimensional Color Correction Table for Each Color of RGB (Step 230) Generation Processing of Color Correction Table Next, referring to FIG. 5, generation of a color correction table in the projector 20 according to the first embodiment of the present invention. Generation processing of the color correction table by the unit 150 (processing in step 230 of FIG. 4) will be described.

In the color correction table generation processing, first, color correction curve calculation processing 1 (correction for changes in the brightness of external illumination) (step 322) and color correction curve calculation processing 2 (for changes in the color of the projection surface). Correction) (Step 3
23) and color correction curve calculation processing 3 (correction for changes in color of external illumination) (step 324). Next, three rounds of correction curve rounding processing 1, 2 and 3 are performed (steps 325, 326 and 32).
7). The correction curve calculation processing and the correction curve rounding processing will be described in detail later.

Then, a new one-dimensional color correction table is generated based on the calculated correction curve (step 328). Then, returning to step 232 in FIG. 4, the one-dimensional color correction table referred to by the color correcting unit 120 is rewritten by the newly generated one-dimensional color correction table (step 232) and the process returns to step 206 in FIG. .

Correction Curve Calculation Process 1 (Correction for Change in Brightness of External Illumination) Next, the correction curve calculation process 1 will be described with reference to FIG.

First, the γ curve is standardized under each environment (step 330). W (white), R (red), G (green),
Since all B (blue) correction curves are the same curve, the correction curve for W is calculated as an example in the present embodiment. The γ curve under each environment (in the case of a dark room and in the presence of external lighting) is assumed as follows. Here, γ is the gradation characteristic of the target projector. It is appropriate that gamma is obtained by actually measuring the gradation characteristics of the target projector and an average value thereof is used. In this embodiment, as an example, γ = 2.2. In case of dark room: Fd (Din) ＝ Yw ・ Din ^γ … (12) When external lighting is present: Fi (Din) ＝ Yw ・ Din ^γ ＋ Yi… (13) Fig. 7 shows the γ curve under each environment.

Here, F is the total brightness of the reflected light from the screen, Din is the RGB digital input value (0 to 255 gradations) standardized to 0 to 1, Yw is the white brightness of the projector, and Yi is Is the brightness of the lighting. And these equations (1
2) and Equation (13) under the assumption that the eyes are acclimatized with the brightness (Yw in the case of a dark room, Yw + Yi when outside the external light exists) when the projector outputs white under each environment. Standardize. That is, the formula (12) and the formula (13) are used to determine the brightness when the projector outputs white under each environment (in a dark room: Y
w, Outside of external lighting: Standardize so that Yw + Yi) becomes 1. Specifically, in the case of a dark room: F'd (Din) = Fd (Din) / Yw = Din ^γ (14) When external lighting is present: F'i (Din) = Fi (Din) / (Yw + Yi ) = become ^{(Yw · Din γ + Yi)} / (Yw + Yi) ... (15).

FIG. 8 shows the standardized γ curve under each environment.

Next, the γ curves are superposed at the reference point Do (step 332). As shown in FIG. 9, at the reference point Do,
F'd (Din) has the same value as F'i (Din), so F'd (Din)
in) is translated in the F′-axis direction by {F′i (Do) −F′d (Do)}. Specifically, F "d (Din) = F'd (Din) + {F'i (Do) -F'd (Do)} = F'd (Din) -F'd (Do) + F ' i and (Do). here, the use of formula (14) and formula (15), F "d ( Din) = Din γ -Do γ + (Yw · Do γ + Yi) / (Yw + Yi) ... (16 ).

Then, the first correction curve is calculated using the equation (16) (step 334).

As described above, in the present embodiment, as shown in FIG. 9, the output value of the correction curve in the presence of external illumination and the output value of the correction curve in the dark room match near the reference point Do. So that the first correction curve is formed.

Then, by correcting the input gradation data so that the relative contrast (gradient of the γ curve) in the vicinity of the reference point Do does not change depending on the presence or absence of external illumination, the output image depending on the presence or absence of external illumination is corrected. Reduce color changes.

The above expression is expressed as follows.

F'i (Dout1) = F "d (Din) (17) Here, Dout1 is the input gradation data corrected by the first correction curve.Equations (15) and (16) Substituting into equation (17), (Yw · Dout1 ^γ + Yi) / (Yw + Yi) = Din ^{γ −} Do ^γ + (Yw · Do
^{γ + Yi) / (Yw +} Yi) than this, Dout1 = [(1 + Yi / Yw) Din γ - (Yi / Yw) Do γ] 1 / γ ... (18) tone at the heart of the time of correcting the contrast deterioration due to illumination The first correction curve changes variously by changing Do. Generally, when the value of Do is small, the first correction curve as shown in FIG. 10 is obtained, and the projection screen looks white and has a light color tone. On the other hand, if you increase the value of Do,
The first correction curve shown in FIG. 11 is obtained, the projection screen looks black, and the gradation change at low gradation is further reduced (so-called gradation collapse becomes remarkable). By setting Do to an appropriate value, it is possible to make a correction that emphasizes vividness without changing the overall brightness of the projected image so much as it was before the correction. As a result of evaluation by experiments, it was confirmed that the Do value is suitable in the vicinity of the middle gradation (about 0.25 ≦ Do ≦ 0.50).

Further, as shown in FIG. 12, the correction amount ΔF
Can be adjusted by α1 (0 ≦ α1 ≦ 1) to adjust the correction amount. This is to prevent unnatural image reproduction due to overcorrection. Formula (18) of Dout1 when adjusting the correction amount
Is, Dout1 = - becomes [(1 + α1 · Yi / Yw) Din γ (α1 · Yi / Yw) Do γ] 1 / γ ... (19). Thus, expression of the first correction curve for each color of RGB _{is, D R out1 = [(1} + α1 · Yi / Yw) D R in γ - (α1 · Yi / Yw) Do γ] 1 / γ ... (20) D G out1 = [(1 + α1 ・ Yi / Yw) D _G in ^γ- (α1 ・ Yi / Yw) Do ^γ ] ^{1 / γ} (21) D _B out1 ＝ [(1 + α1 ・ Yi / Yw) D _B in ^γ- ( α1 ・ Yi / Yw) Do ^γ ] ^{1 / γ} (22)

Multiplying the correction amount by α1 corresponds to multiplying the luminance Yi of the illumination by α1 as a result. The value of α1 is preferably within the range of 0.8 ≦ α1 ≦ 1.

The first correction curve is calculated by the equations (20) to (22) (step 334), the process returns to step 323 of FIG. 5, and the correction curve calculation process 2 is performed.

Correction Curve Calculation Processing 2 (Correction for Change in Color of Projection Surface) Next, the correction curve calculation processing 2 (calculation of the second correction curve (step 346)) will be described with reference to FIG. .

The primary color (RGB) of the projector is the secondary
The change in chromaticity due to the difference in the projection plane is
It is difficult to prevent the brightness ratio y from the target projection surface._R, Y_G, Y
_BIs the luminance ratio y of the reference projection plane._R0, Y_G0, Y_B0And one
If the correction is made to match, the projection plane for all colors
The change in chromaticity due to the difference is corrected. RGB before correction
Digital input value standardized in the range of 0 to 1 is D_Ri
n2, D_Gin2, D_Bin2 and input the corrected RGB digital
D is a standardized force value in the range of 0 to 1._Rout2, D _Gout
2, D_BIf out2, the formula of the correction curve is D_Rout2 ＝ [y_R’/ Max (y_R’、 Y_G’、 Y_B’)]^{1 / γ}× D_Rin2, y_R’= Y_R0/ Y _R      … (twenty three) D_Gout2 ＝ [y_G’/ Max (y_R’、 Y_G’、 Y_B’)]^{1 / γ}× D_Gin2, y_G’= Y_G0/ y_G= 1… (24) D_Bout2 ＝ [y_B’/ Max (y_R’、 Y_G’、 Y_B’)]^{1 / γ}× D_Bin2, y_B’= Y_B0/ y_B    … (twenty five) Becomes Where max (y_R’、 Y_G’、 Y_B’) Is y_R’,
y_G’、 Y_B′ Indicates the maximum value. Correct in this way
By doing so, colorimetric changes in chromaticity due to the projection surface can be complemented.
Can be corrected.

In this way, the chromaticity change due to the projection surface can be corrected colorimetrically, but the correction amount α3 (0 <α3 <is taken into consideration in consideration of the adaptability of the human eye and the effect of contrast. When adjusting 1), the correction curve is: D _R out2 = [1-α3 {1-y _R '/ max (y _R ', y _G ', y _B ')}] ^{1 / γ} × D _R in2 ... (26) D _G out2 = [1-α3 {1-y _G '/ max (y _R ', y _G ', y _B ')}] ^{1 / γ} × D _G in2 (27) D _B out2 = [ 1-α3 {1-y _B '/ max (y _R ', y _G ', y _B ')}] ^{1 / γ} × D _B in2 (28)

[0063] _{Here, ΔRgain = y R '/ max} (y R', y G ', y B') ΔGgain = y G '/ max (y R', y G ', y B') ΔBgain = y B Assuming '/ max (y _R ', y _G ', y _B '), (26) to (28) are: D _R out2 = {1-α3 (1-ΔR gain)} ^{1 / γ} × D _R in2 ... (29) D _G out2 = {1-α3 (1-ΔG gain)} ^{1 / γ} × D _G in2 (30) D _B out2 = {1-α3 (1-ΔB gain)} ^{1 / γ} × D _B in2 (31)

When the color of the projection plane obtained by the measurement is corrected by 100% (α3 = 1), the colorimetrically correct correction is performed. However, when there is external lighting, the color of the projection surface exists around the projected image, so the correction is stronger than it actually is due to the color contrast between the projected image and the projection surface and the effect of eye adaptation to external lighting. Looks like it's hanging. In order to eliminate this phenomenon, the correction amount is adjusted. The correction amount α3 needs to be adjusted while actually evaluating the image under each environment. The value of α3 is preferably 0.5 to 1.0.

The second correction curve is calculated according to the equations (29) to (31) (step 346) and the process returns to step 324 in FIG. 5 to perform the correction curve calculation process 3.

Here, both the correction curve calculation processing 1 and the correction curve calculation processing 2 are processing for relatively correcting the input values. That is, the equation (20) of the first correction curve
In (22) and the expressions (29) to (31) of the second correction curve, the input parameter is multiplied by the correction parameter to obtain the output value. Therefore, the correction curve calculation process 1 and the correction curve calculation process 2 can be performed in the reverse order, that is, step 322 and step 323 in FIG. 5 can be interchanged.

Correction Curve Calculation Process 3 (Correction for Change in Color of External Illumination) Next, the correction curve calculation process 3 will be described with reference to FIG.

A third correction curve is calculated using r _i , g _i , b _i (step 354). The perfect color reproduction is represented by the formula (3
This is realized by subtracting the r _i , g _i , and b _i obtained in 4) as they are from the RGB output of the projector as an offset. However, this method is unrealistic because the gradation of the projector is largely destroyed.

Therefore, in the present embodiment, as shown in FIG. 15, the differences ΔRoffset and ΔGo from the average values of r _i , g _i , and b _i.
A method is used in which ffset and ΔBoffset are subtracted as offsets. As a result, the color obtained by superimposing the illumination color and the offset color has the same chromaticity as the gray of the projector.

In this way, the effect of the color of the illumination can be corrected colorimetrically, but if the correction amount is adjusted in consideration of the adaptability of the human eye and the effect of contrast, ΔRoffse
The values of t, ΔGoffset, and ΔBoffset are multiplied by (α2) (0 <α2 <
1) Do. 10 for the color of the lighting obtained by the measurement
When 0% (α2 = 1) correction is applied, colorimetrically correct correction is performed, but unnatural image reproduction may occur due to excessive correction. In order to eliminate this phenomenon, the correction amount is adjusted. The correction amount α2 needs to be adjusted while actually evaluating the image under each environment. The value of α2 is preferably 0.2 to 0.5.

By the way, the RGB output of the projector is r, g, b, and the corrected output of the projector is r ', g',
When the correction process is expressed by an equation as b ′, it becomes as follows. However, for simplicity of explanation, only the formula of R is shown. That is, from the equation (33), R of the projector is
If the output r (D _R ) (= D _R ^γ ) (32) is adjusted using the correction amount α2, the corrected output r ′ (D _R ) of the projector _R is r ′ (D _R ) = D _R ^γ- α2 ΔRoffset (33) ΔRoffset = r _i − (r _i + g _i + b _i ) / 3. From the above, if the input value before correction is D _R in3 and the input value after correction is D _R out, the third correction curve is r (D _R out) = r ′ (D _R in3) (34) Becomes From Expression (33) and Expression (34), D _R out = (D _R in3 ^γ- α2ΔRoffset) ^{1 / γ} (35) Similarly, D _G out and D _B out are D _G out = (D _G in3 ^γ −α2ΔG offset) ^{1 / γ} (36) D _B out = (D _B in3 ^γ −α 2 ΔB offset) ^{1 / γ} (37) Becomes

The final correction curve is obtained by connecting the first correction curve, the second correction curve and the third correction curve obtained as described above (step 35).
6). That is, in the formulas (20) to (22) and the formulas (29) to (31), D _R in2 = D _R out1 D _G in2 = D _G out1 D _B in2 = D _B out1 and the formula (29) In (31) and equations (35) to (37), if D _R in3 = D _R out2 D _G in3 = D _G out2 D _B in3 = D _B out2, the final correction curve is D _R out = [{1-α3 (1-ΔRgain)} × {(1 + α1 ・ Yi / Yw) D _R in ^γ − (α1 ・ Yi / Yw) Do ^γ } −α2ΔRoffset)] ^{1 / γ} … (38) D _G out = [{1-α3 (1-ΔGgain)} × {(1 + α1 ・ Yi / Yw) D _G in ^γ − (α1 ・ Yi / Yw) Do ^γ } −α2ΔGoffset)] ^{1 / γ} … (39) D _R out ＝ [{1-α3 (1-ΔBgain)} × {(1 + α1 · Yi / Yw) D _B in ^γ− (α1 · Yi / Yw) Do ^γ } −α2ΔB offset)] ^{1 / γ} (40)

FIG. 16 shows an example of the final correction curve.

The final correction curve is obtained by the equations (38) to (40) (step 356), and step 325 in FIG.
Rounding processing 1 of the correction curve is performed.

Correction Curve Rounding Processing 1 Next, correction curve rounding processing 1 is performed (step 32).
5).

As shown in FIG. 16, in the correction curve obtained by the equation (38), there are gradations where Dout remains 0 and does not change in the low gradation area and the high gradation area. Therefore, the correction curve is rounded according to the following procedure. First, the following equation Dout4 = [Dout− | (Dout−Din) | ^β ] (Dout> Din) (41) Dout4 = [Dout + | (Dout−Din) | ^β ] (Dout <Din) (42) Is used to calculate Dout4 from Dout. Here, β is a parameter for adjusting the degree of rounding. It was confirmed that β = 1.5 is appropriate according to the evaluation result performed while actually viewing the image. According to the equations (41) and (42), there is no gradation where Dout remains 0 and does not change. In this way, after the correction curve rounding process 1 is completed, the correction curve rounding process 2 is performed.

Rounding process 2 of correction curve Next, rounding process 2 of the correction curve is performed (step 32).
6).

In the correction curve rounding processing 2, for each value of the equation (41) or the equation (42), an average value of the values at a total of 5 points including two points before and after the value is calculated.

Taking the case of Din × 255 = 128 as an example, Dout5 (128) = [Dout4 (112) + Dout4 (120) + Dout4 (128) + Dout4 (136) + Dout4 (144)] / 5 ... (43) Become. By performing the rounding process 2 of the correction curve, the correction curve becomes smooth.

However, the following Din × 255 = 0, 8, 248, 255
4 points, Dout5 (0) = Dout4 (0)… (44) Dout5 (8) ＝ [Dout4 (0) ＋ Dout4 (8) ＋ Dout4 (16)] / 3… (45) Dout5 (248) ＝ [Dout4 (240) + Dout4 (248) + Dout4 (255)] / 3 ... (46) Dout5 (255) = Dout4 (255) ... (47). In this way, the correction curve rounding process 3 is performed after the correction curve rounding process 2 is completed.

Rounding Process 3 of Correction Curve Next, rounding process 3 of the correction curve is performed (step 32).
7).

In the correction curve rounding process 3, the following equation Dout6 = Din + (Dout5-Din) [1-{(0.25-Din) /0.25} ^θ ] (Din × 255 <64) (48) Dout6 = Din + (Dout5−Din) [1-{(Din−0.75) /0.25} ^θ ] (Din × 255> 192) (49) is used to calculate Dout6. This Dout6 becomes the final correction result.

The results are shown in FIG. As shown in FIG. 17, in the vicinity of Din × 255 = 0,255, no correction is applied, and the maximum brightness and contrast of the projector are maintained. Θ in equations (48) and (49) is Din × 25
This is a parameter for adjusting the degree of attenuation of the correction amount around 5 = 0, 255, and it was confirmed that θ = 5.0 is appropriate according to the evaluation result performed while actually viewing the image.

If Dout5 (0) and Dout5 (255) are already 0, the correction curve rounding process 3 (step 327) is not performed, and Dout6 = Dout5.

After the completion of the correction curve rounding processing 3, the newly generated one-dimensional color correction table
The one-dimensional color correction table for each color of RGB is rewritten (step 232), and the process returns to step 206 in FIG.

Second Embodiment System Configuration FIG. 18 is a schematic explanatory diagram of an image display system using a projector 20 according to the second embodiment of the present invention. The image display device of the present invention includes a projector, a CR
T, liquid crystal display, etc. are also included.

In the first embodiment, as shown in FIG. 1, a first optical sensor 165 for measuring external environmental data,
While the second optical sensor 170 for measuring the data of the displayed image is separately provided, in the second embodiment, one optical sensor 170 has external environment data,
The data of the displayed image is measured together. The first embodiment and the second embodiment are different only in this point and are the same in other points.

In the second embodiment, as shown in FIG. 18, the external environment data is measured in the state of 170 ', and when a change in the external environment data is detected, the data measurement direction is changed to the screen direction. To measure the image data.

FIG. 19 shows a functional block diagram of the image processing section 100 in the projector 20 according to the second embodiment of the present invention.

Image processing unit 10 in the projector of the present invention
0 is an A / D conversion unit 110 that converts an analog image input signal into a digital signal, and a color correction unit 120 that applies a one-dimensional color correction table to each RGB image input signal to perform desired color correction. A D / A converter 130 for converting a digital signal into an analog signal, an L / V (light valve) driver 140 for driving a liquid crystal light valve to project and display an image, and a dark room A device characteristic storage memory 160 for storing the color characteristic information of the projector when it is output to the reference projection plane, and 1 in FIG.
When the external measurement data (lightness as an example in the embodiment) is measured when the data measurement direction is the illumination direction as indicated by 70 ', and the data measurement direction is the screen direction as indicated by 170 in FIG. In addition, an optical sensor 170 for measuring the brightness of the light reflected by the projector and the screen of the external lighting, and a lightness detection unit 180 for detecting the lightness based on the external environment data from the optical sensor 170.
And a lightness change detection unit 185 for detecting a lightness change based on external environmental data from the light sensor 170, and a colorimetric value of the light sensor 170 and a device characteristic storage memory according to the detected lightness / lightness change. And a color correction table generation unit 150 that generates a color correction table in consideration of the influence of external lighting, based on the information stored in.

The operation of the image processing section 100 and the color correction table generation processing are the same as those in the first embodiment, and therefore their explanations are omitted.

According to the image display device of the second embodiment, the change of the external environment is judged based on the external environment data from the optical sensor 170, and the brightness of the external illumination is also judged based on the measured image data from the optical sensor 170. Alternatively, since the color correction table is rewritten in consideration of the color or the change in the color of the projection surface, it is possible to appropriately reproduce the color.

Third Embodiment System Configuration FIG. 20 is a schematic explanatory diagram of an image display system using a projector 20 according to the third embodiment of the present invention. The image display device of the present invention includes a projector, a CR
T, liquid crystal display, etc. are also included.

In the second embodiment, as shown in FIG.
The measurement direction of the optical sensor 170 is changed so that one optical sensor 170 measures both the external environment data and the displayed image data. Meanwhile, the third
In the embodiment, the data measurement direction is changed using the light reflection plate (a white plate is used as an example) 75, and one optical sensor 170 measures both the external environment data and the displayed image data. To do. The second embodiment and the third embodiment are different only in this point and are the same in other points.

In the third embodiment, as shown in FIG. 20, the optical sensor 170 measures the external environment data with the reflector plate 75 ', and when a change in the external environment data is detected, the reflector plate Change the direction to the state of 75, and
70 measures the image data.

A functional block diagram of the image processing unit 100 in the projector 20 according to the third embodiment is shown in FIG. 19. The image processing unit 1 in the projector 20 according to the second embodiment shown in FIG.
00 is the same as the functional block diagram of FIG. The operation of the image processing unit 100 and the color correction table generation processing are also the same as those in the first and second embodiments. For this reason,
These explanations are omitted.

According to the image display device of the third embodiment, the change in the external environment is judged based on the external environment data from the optical sensor 170, and the brightness of the external illumination is also determined based on the measured image data from the optical sensor 170. Alternatively, since the color correction table is rewritten in consideration of the color or the change in the color of the projection surface, it is possible to appropriately reproduce the color.

[Brief description of drawings]

FIG. 1 is a projector 2 according to a first embodiment of the invention.
It is a schematic explanatory drawing of the image display system using 0.

FIG. 2 is a projector 2 according to the first embodiment of the invention.
3 is a functional block diagram of an image processing unit in 0. FIG.

FIG. 3 is an image processing unit 10 in the projector 20 of the present invention.
6 is a flowchart for explaining the operation of 0.

FIG. 4 is a flowchart for explaining a color correction table generation / rewriting process by a color correction table generation unit 150 in the projector 20 of the present invention.

FIG. 5 is a projector 20 according to the first embodiment of the invention.
6 is a flowchart for explaining a color correction table generation process by a color correction table generation unit 150 in FIG.

FIG. 6 is a flowchart for explaining a correction curve calculation process 1 (correction for a change in brightness of external illumination) according to the present invention.

FIG. 7 is a graph showing a γ curve under each environment.

FIG. 8 is a graph showing a standardized γ curve under each environment.

FIG. 9 is a graph showing a state in which standardized γ curves under each environment are combined at a reference point Do.

FIG. 10 is a graph (1) showing an example of a correction curve when Do is changed.

FIG. 11 is a graph (2) showing an example of a correction curve when Do is changed.

FIG. 12 is a diagram for explaining adjustment of a correction amount α1 of a first correction curve.

FIG. 13 is a flowchart for explaining a correction curve calculation process 2 (correction for a change in color of the projection surface) according to the present invention.

FIG. 14 is a flowchart for explaining a correction curve calculation process 3 (correction for color change of external illumination) according to the present invention.

FIG. 15 is a diagram for explaining a calculation principle of a third correction curve.

FIG. 16 is a graph showing an example of a correction curve (before rounding).

FIG. 17 is a graph showing an example of a correction curve (after rounding processing).

FIG. 18 is a schematic explanatory diagram of an image display system using the projector 20 according to the second embodiment of the invention.

FIG. 19 is a projector 2 according to a second embodiment of the invention.
3 is a functional block diagram of the image processing unit 100 in 0. FIG.

FIG. 20 is a schematic explanatory diagram of an image display system using a projector 20 according to a third embodiment of the invention.

[Explanation of symbols]

10 screens 20 projector 50 lighting equipment 75 Light reflector 80 External lighting 100 Image processing unit 110 A / D converter 120 color correction unit 130 D / A converter 140 L / V drive 150 color correction table generator 165 First optical sensor 170 Second optical sensor 180 Brightness detector 185 Brightness change detector

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5C066 AA03 CA08 CA17 CA23 EA13                       FA02 GA01 HA03 KE07 KM11                 5C082 AA21 BA20 BA34 BA41 CA12                       CA81 CB03 DA51 DA87 MM10

Claims (11)

[Claims] 1. An image display device for displaying an image by performing desired image processing on image input data, comprising first data measuring means for measuring external environmental data, and data of the displayed image. And a second data measuring means for measuring the external environment change detecting means for detecting a change in the external environment based on the external environment data measured by the first data measuring means. When detected, the second
An image display device for measuring data of an image displayed by a data measuring means. 2. The image display device according to claim 1, wherein the first data measuring unit measures the brightness as the external environment data, and the change amount of the brightness within a predetermined time is equal to or more than a threshold value. An image display device for measuring data of an image displayed by the second data measuring means. 3. The image display device according to claim 2, wherein the first data measuring unit measures lightness as external environmental data, and the amount of change in lightness within a predetermined time is 30 to 50.
An image display device for measuring the data of the image displayed by the second data measuring means when the percentage is equal to or higher than the percentage. 4. The image display device according to claim 2, wherein the predetermined time is about 10 seconds or less. 5. The image display device according to claim 1, wherein the first data measuring unit measures lightness as external environment data, and the measured lightness is a predetermined value or more. In case of
An image display device for measuring data of an image displayed by the second data measuring means. 6. The image display device according to claim 5, wherein the predetermined value is 50 to 100 lux. 7. The image display device according to claim 1, wherein the first data measuring unit and the second data measuring unit are constituted by one sensor. 8. The image display device according to claim 1, wherein the first data measuring unit and the second data measuring unit are constituted by different sensors. 9. An image processing method for image input data input to an image display device, comprising: a first data measuring step for measuring external environmental data; and a second data for measuring data of a displayed image. A measurement step, and an external environment change detection step for detecting a change in the external environment based on the external environment data measured by the first data measurement step, and when a change in the external environment is detected, The second
An image processing method for measuring data of a displayed image in a data measuring step. 10. A program for causing a computer to perform image processing on image input data input to an image display device, the first data measuring process for measuring external environmental data, and a program for displaying a displayed image. A second data measurement process for measuring data, an external environment change detection process for detecting a change in the external environment, and a change in the external environment are detected based on the external environment data measured by the first data measurement process. And a program for causing a computer to perform a process of performing data measurement of a displayed image by the second data measurement process. 11. A computer-readable recording medium in which the program according to claim 10 is recorded.