JP4225231B2 - Image processing apparatus, image projection apparatus, method, program, and recording medium - Google Patents

Description

  The present invention relates to image processing (color conversion method) in a multi-primary color display device.

  Conventionally, in liquid crystal display devices, projectors, etc., color conversion that converts input three primary colors (for example, RGB input signals) into color primary color signals of each primary color of a multi-primary color display device (a display device that uses four or more primary colors). Has been done.

  For example, Patent Document 1 discloses a color television transmission system that converts a signal for displaying three primary colors into a signal for displaying multiple primary colors of four or more primary colors. In the color conversion by the transmission method, only three colors are selected from the four or more primary colors to be color-converted, and a signal for displaying the multi-primary colors is obtained by mixing these three colors.

  Patent Document 2 discloses a color reproduction system including color conversion means for converting an input tristimulus value into a color image signal of each primary color of a multi-primary color display device. In color conversion in the color reproduction system, the color conversion area is divided into four tetrahedrons, and signals for multi-primary color display are obtained in each area. Again, signals for multi-primary color display are obtained using three colors selected from the four primary colors as variables, and the remaining primary colors are zero or maximum values.

JP-A-6-261332 JP 2000-338950 A

  However, in the color conversion described in Patent Document 1 or Patent Document 2, when a signal for displaying three primary colors is converted into a signal for displaying multiple primary colors of four or more primary colors, the output of each primary color for expressing one color is output. Despite the presence of multiple ratios, one of the primary colors is always fixed at zero or the maximum value. For this reason, when a signal for displaying three primary colors is converted into a signal for displaying four or more primary colors, an optimum output ratio according to the situation cannot be selected, and appropriate color reproduction is impossible.

  Accordingly, an object of the present invention is to provide an image processing apparatus and the like that can perform appropriate color reproduction.

  An image processing apparatus according to an aspect of the present invention includes a color conversion unit that converts an M primary color display signal into an N primary color display signal, the natural number N being greater than the natural number M, and a weighting of each primary color of the N primary color display signal Output ratio determination means for determining an output ratio of each primary color of the N primary color display signal based on a coefficient, and based on the output ratio determined by the output ratio determination means, the color conversion means displays the M primary color display. The signal for converting is converted into a signal for displaying N primary colors.

  According to the image processing apparatus configured as described above, the M primary color display signal is converted into the N primary color display signal by the color conversion means (N> M, N and M are natural numbers), and the output ratio determination means. The output ratio of each primary color of the N primary color display signal is determined based on the weighting coefficient of each primary color of the N primary color display signal. Then, based on the output ratio determined by the output ratio determining means, the color converting means converts the M primary color display signal into an N primary color display signal. Therefore, by appropriately setting the weighting coefficient of each primary color of the N primary color display signal according to the situation, an optimal output ratio is selected, and appropriate color reproduction becomes possible.

  According to the image processing apparatus of the present invention, the output ratio determining means determines the output ratio so that the luminance ratio of each primary color of the N primary color display signal approaches the ratio of the weighting coefficients of each primary color. Configured.

  The image processing apparatus according to the present invention is configured to increase the weighting coefficient of a primary color with a lower emission luminance.

  The image processing apparatus according to the present invention is configured to increase the weighting coefficient of the primary color as the primary color has better luminous efficiency.

  The image processing apparatus according to the present invention is configured to increase the weighting coefficient of a primary color that has a longer lifetime.

  The image processing apparatus according to the present invention is configured to increase the weighting coefficient of the primary color as the accumulated light emission time is shorter.

  The image processing apparatus according to the present invention is configured such that the primary color with higher energy increases the weighting coefficient of the primary color.

  The image processing apparatus according to the present invention is configured to increase the weighting coefficient of the primary color as the primary color of the image display apparatus has a larger calorific value.

  The image processing apparatus according to the present invention is configured to increase the weighting coefficient of the primary color as the primary color with larger leakage light in the image display apparatus.

  An image projection apparatus according to another aspect of the present invention has a natural number N larger than a natural number M, color conversion means for converting an M primary color display signal into an N primary color display signal, and each primary color of the N primary color display signal. Output ratio determining means for determining an output ratio of each primary color of the N primary color display signal based on a weighting coefficient, and based on the output ratio determined by the output ratio determining means, the color conversion means is the M primary color The display signal is converted into an N primary color display signal.

  An image processing method according to still another aspect of the present invention includes a color conversion step of converting the M primary color display signal into an N primary color display signal, the natural number N being greater than the natural number M, and the primary colors of the N primary color display signal. An output ratio determining step for determining an output ratio of each primary color of the N primary color display signal based on the weighting coefficient of the output, and based on the output ratio determined in the output ratio determining step, M in the color conversion step The primary color display signal is converted into an N primary color display signal.

  The program according to still another aspect of the present invention provides a color conversion process for converting the M primary color display signal into the N primary color display signal, and the weighting of each primary color of the N primary color display signal. An output ratio determination process for determining an output ratio of each primary color of the N primary color display signal based on the coefficient, and an M primary color display signal in the color conversion process based on the output ratio determined in the output ratio determination process. The process of converting the signal to the N primary color display signal is executed by a computer.

  In a recording medium according to still another aspect of the present invention, the natural number N is larger than the natural number M, a color conversion process for converting the M primary color display signal into the N primary color display signal, and the primary color of the N primary color display signal. An output ratio determination process for determining an output ratio of each primary color of the N primary color display signal based on a weighting factor, and an M primary color display signal in the color conversion process based on the output ratio determined in the output ratio determination process Is converted to N primary color display signals, and a program for causing the computer to execute is recorded and readable by the computer.

  Embodiments of the present invention will be described below with reference to the drawings.

Overall Configuration of Image Processing Device FIG. 1 is an explanatory diagram showing the overall configuration of an image processing device 16 as an embodiment of the present invention. In this embodiment, three primary color display signals (YUV signal or R (red) G (green) B (blue) signal) are converted into four primary color display signals (R '(red) G' (green) B '(blue). The case of conversion to E ′ (emerald green) signal will be described.

The image processing apparatus includes a YUV → RGB conversion unit 16a, a γ conversion unit 16b, an rgb → XYZ conversion unit 16c, an r ₀ g ₀ b ₀ e ₀ calculation unit 16d, and an r ₁ g ₁ b ₁ e ₁ calculation. 16e, a luminance ratio determining unit 16f, a weighting coefficient determining unit 16g, a calorific value / leakage light detecting unit 16h, an inverse γ converting unit 16j, and a light emitting / absorbing light amount integrating unit 16k. The

  As an input image signal, any of a YUV input image signal and an RGB input image signal can be used. In the case of a YUV input image signal, it is converted in advance into an RGB input image signal by the YUV → RGB conversion unit 16a. The RGB input image signal is converted into a luminance ratio rgb by the γ converter 16b, and then converted into XYZ values by the rgb → XYZ converter 16c. Since the processes by the YUV → RGB conversion unit 16a, γ conversion unit 16b, and rgb → XYZ conversion unit 16c are well known, detailed description thereof will be omitted.

Then, the r ₀ g ₀ b ₀ e ₀ calculation unit 16d and the r ₁ g ₁ b ₁ e ₁ calculation unit 16e perform two sets of luminance ratios (r ₀ , g ₀ , b ₀ , e ₀ ) under a predetermined condition. And (r ₁ , g ₁ , b ₁ , e ₁ ) are obtained. Then, the luminance ratio determining unit 16f, based on the weighting coefficient supplied from the weighting coefficient determining unit 16g, sets two luminance ratios (r ₀ , g ₀ , b ₀ , e ₀ ) and (r ₁ , g ₁ , b ₁ , e ₁ ), the luminance ratio r′g′b′e ′ of the four primary colors for representing the color (X, Y, Z) of the input image signal is obtained. The weighting coefficient determination unit 16g determines the weighting coefficient based on data from the heat generation / leakage light detection unit 16h and the light emission / absorption light amount integration unit 16k.

  Then, the luminance ratio r′g′b′e ′ of the four primary colors for representing the color (X, Y, Z) of the input image signal is output by the inverse γ conversion unit 16j to the output image signal R′G′B′E ′. (Corresponding to “the output ratio of each primary color of the N primary color display signal” of the present invention). Since the processing by the inverse γ conversion unit 16j is well known, detailed description thereof is omitted.

The processes in the r ₀ g ₀ b ₀ e ₀ calculation unit 16d, the r ₁ g ₁ b ₁ e ₁ calculation unit 16e, the luminance ratio determination unit 16f, and the weighting coefficient determination unit 16g will be described in detail later.

Here, YUV → RGB conversion unit 16a, γ conversion unit 16b, rgb → XYZ conversion unit 16c, r ₀ g ₀ b ₀ e ₀ calculation unit 16d, r ₁ g ₁ b ₁ e ₁ calculation unit 16e, luminance ratio determination unit The 16f and the inverse γ conversion unit 16j correspond to the “color conversion unit” of the present invention. Further, the luminance ratio determination unit 16f, the weighting coefficient determination unit 16g, and the inverse γ conversion unit 16j correspond to the “output ratio determination unit” of the present invention.

Color Conversion Processing in Image Processing Device 16 FIG. 2 is a flowchart for explaining color conversion processing in the image processing device 16. This is a process performed by the CPU of the computer. With reference to FIG. 2, the processing of the image processing apparatus 16 will be described in more detail.

  First, as described above, the RGB input image signal (or YUV input image signal) is converted into an XYZ signal by the YUV → RGB conversion unit 16a, the γ conversion unit 16b, and the rgb → XYZ conversion unit 16c (S10).

Next, the XYZ signal is converted into a luminance ratio of arbitrary three primary colors selected from the four primary colors of the display device by the r ₀ g ₀ b ₀ e ₀ calculation unit 16d (S12). In this embodiment, XYZ values obtained in S10 are converted into luminance ratios of the three primary colors selected by the display device using RGB from among the four primary colors (RGBE) of the display device. The luminance of the fourth primary color (primary color E in this embodiment) is zero. In the mathematical formula, the following formula (1) is shown.

ここで、Ｘ_RＹ_RＺ_Rは原色Ｒの最大輝度の三刺激値であり、Ｘ_GＹ_GＺ_Gは原色Gの最大輝度の三刺激値であり、Ｘ_BＹ_BＺ_Bは原色Bの最大輝度の三刺激値である。

Here, X _R Y _R Z _R is the tristimulus value of the maximum luminance of the primary color R, X _G Y _G Z _G is the tristimulus value of the maximum luminance of the primary color G, and X _B Y _B Z _B is the primary color B. The tristimulus value of the maximum brightness.

Similarly, the XYZ signal obtained in S10 is displayed in a state where the luminance of the fourth primary color (primary color E in the present embodiment) is fixed to the maximum value by the r ₁ g ₁ b ₁ e ₁ calculation unit 16e. It is converted into the luminance ratio of the selected three primary colors of the apparatus (S14). In the mathematical formula, the following formula (2) is shown.

ここで、Ｘ_RＹ_RＺ_Rは原色Ｒの最大輝度の三刺激値であり、Ｘ_GＹ_GＺ_Gは原色Gの最大輝度の三刺激値であり、Ｘ_BＹ_BＺ_Bは原色Bの最大輝度の三刺激値であり、Ｘ_EＹ_EＺ_Eは原色Ｅの最大輝度の三刺激値である。

Here, X _R Y _R Z _R is the tristimulus value of the maximum luminance of the primary color R, X _G Y _G Z _G is the tristimulus value of the maximum luminance of the primary color G, and X _B Y _B Z _B is the primary color B. tristimulus values of the maximum luminance of, X _E Y _E Z _E are the tristimulus values of maximum intensity of the primary colors E.

  Then, the luminance ratio determination unit 16f obtains the luminance ratio of the four primary colors for representing the color (X, Y, Z) of the input signal (S16). The luminance ratio of the four primary colors for representing the color (X, Y, Z) of the input signal is expressed by the following equation (3):

に示すように、ｅを変数とした（ｒ₀,ｇ₀,ｂ₀,ｅ₀）と（ｒ₁,ｇ₁,ｂ₁,ｅ₁）との線形結合で表すことができる。

As shown in FIG. 2, it can be expressed by a linear combination of (r ₀ , g ₀ , b ₀ , e ₀ ) and (r ₁ , g ₁ , b ₁ , e ₁ ) with e as a variable.

In order to make the luminance ratios of the four primary colors uniform within a possible range, the following expression (4) and condition (5):
0 ≦ r ′ ≦ 1, 0 ≦ g ′ ≦ 1, 0 ≦ b ′ ≦ 1, 0 ≦ e ′ ≦ 1 (4)
Evaluation function F (e ′) is minimized (dF (e ′) / de ′ = 0) (5)
Find e 'that satisfies

In this embodiment, the evaluation function F (e) uses the weighting coefficients w _R , w _G , w _B , and w _E for each primary color supplied from the weighting coefficient determination unit 16g.

で定義される。重み付け係数決定部１６ｇにおける処理については後で詳細に説明する。式(6)において、評価関数Ｆ(e)が最小となる（条件(5)）とは、ｒ’／ｗ_R，ｇ’／ｗ_G，ｂ’／ｗ_B，ｅ’／ｗ_Eとこれらの平均値との差の二乗和が最小になることを意味している。すなわち、ｒ’／ｗ_R，ｇ’／ｗ_G，ｂ’／ｗ_B，ｅ’／ｗ_Eがこれらの平均値に最も近づくこと、つまりｒ’,ｇ’,ｂ’,ｅ’がｗ_R，ｗ_G，ｗ_B，ｗ_Eの比に最も近づくことを意味する。

Defined by The processing in the weighting coefficient determination unit 16g will be described in detail later. In Expression (6), the evaluation function F (e) is minimized (condition (5)) is r ′ / w _R , g ′ / w _G , b ′ / w _B , e ′ / w _E and these It means that the sum of squares of the difference from the average value of is minimized. That is, r ′ / w _R , g ′ / w _G , b ′ / w _B , e ′ / w _E are closest to these average values, that is, r ′, g ′, b ′, e ′ are w _R. , W _G , w _B , w _E is the closest.

Here, c _i = c _i0 + e′Δc _i (7)
Δc _i = c _i1 −c _i0 (8)

{ｃ_ij}＝{ｒ_j／ｗ_R，ｇ_j／ｗ_G，ｂ_j／ｗ_B，ｅ_j／ｗ_E} ｊ＝0,1 …（10）
である。式(7)は、式(3)を新たな記号で書き直したものである。また、式(9)においてＮは原色の数に相当する。

{c _ij } = {r _j / w _R , g _j / w _G , b _j / w _B , e _j / w _E } j = 0,1 (10)
It is. Equation (7) is a rewrite of equation (3) with a new symbol. In Equation (9), N corresponds to the number of primary colors.

  The value of e ′ that satisfies the condition (5) can be obtained as follows.

  First, from Equation (6) and Equation (9),

そして、評価関数Ｆ(e’)をｅ’で微分すると、

Then, differentiating the evaluation function F (e ′) by e ′,

となり、これより条件(5)を満たすｅ’の値は、

From this, the value of e ′ that satisfies the condition (5) is

となる。なお、当該実施形態において用いている評価関数Ｆ(ｅ’)およびその解は、原色数Ｎが５以上の場合であってもそのまま適用できる。

It becomes. Note that the evaluation function F (e ′) and its solution used in this embodiment can be applied as they are even when the number of primary colors N is 5 or more.

  If e ′ satisfying Expression (4) is set to emin (minimum value of e ′) ≦ e ′ ≦ emax (maximum value of e ′), the final value of e ′ is the center of e ′, emin, and emax. Value. (R ′, g ′, b ′, e ′) is obtained from the e ′ thus obtained using the equation (3).

  Further, the luminance ratio r′g′b′e ′ of the four primary colors for representing the color (X, Y, Z) of the input image signal is output by the inverse γ conversion unit 16j to the output image signal R′G′B′E ′. (Corresponding to “the output ratio of each primary color of the N primary color display signal” of the present invention) and then supplied to the display device 18 (S18 and S20).

Processing in Weighting Factor Determining Unit 16g The weighting factor determining unit 16g uses the data related to the heat generation amount / leakage light from the heat generation amount / leakage light detection unit 16h and the data related to the light emission amount / absorption light amount from the light emission amount / absorption light amount integration unit 16k. A weighting factor is determined based on this. Hereinafter, the weighting coefficient _{w R, w G, w B} , the method of determining the w _E will be described.

Method (1): When the light emission luminance of each primary color is averaged, the primary color having a smaller light emission luminance increases the weighting coefficient of the primary color. In this case, the weighting factors w _R , w _G , w _B , and w _E are defined as follows.

w _R = 1 / Y _R
w _G = 1 / Y _G
w _B = 1 / Y _B
w _E = 1 / Y _E
Here, Y _R , Y _G , Y _B , and Y _E are the maximum luminance (nit) of the primary color RGBE.

Method (2): When the output ratio is increased for a primary color with higher light emission efficiency, the weighting coefficient of the primary color is increased for the primary color with higher light emission efficiency. By doing so, the power consumption of the display device can be saved. In this case, the weighting factors w _R , w _G , w _B , and w _E are defined as follows.

w _R = e _R
w _G = e _G
w _B = e _B
w _E = e _E
Here, e _R , e _G , e _B , and e _E are the light emission efficiencies (lm / W) of the primary color RGBE.

Method (3): When a primary color having a long lifetime is set to have a higher output ratio, the primary color having a longer lifetime is increased in the weighting coefficient of the primary color. By doing so, the lifetime of the entire display device can be extended. In this case, the weighting factors w _R , w _G , w _B , and w _E are defined as follows.

w _R = H _R
w _G = H _G
w _B = H _B
w _E = H _E
Here, H _R , H _G , H _B , and H _E are the lifetimes (hours) of the primary colors RGBE.

Method (4): When a primary color with a smaller cumulative emission amount (shorter cumulative emission time) has a higher output ratio, a primary color with a smaller cumulative emission amount (shorter cumulative emission time) has a larger weighting coefficient for that primary color. To do. In this way, it is possible to prolong the lifetime of the entire display device by preferentially using the primary colors that are not frequently used. In this case, the weighting factors w _R , w _G , w _B , and w _E are defined as follows.

w _R = 1 / E _R
w _G = 1 / E _G
w _B = 1 / E _B
w _E = 1 / E _E
Here, E _R , E _G , E _B , and E _E are the cumulative emission amounts (lm · sec) of the primary color RGBE, respectively.

Method (5): Method of taking the product of the weighting factor of method (3) and the weighting factor of method (4) (corresponding to “amount of luminescence energy with respect to lifetime”). It is possible to prolong the lifetime of the entire display device by preferentially using non-primary colors. In this case, the weighting factors w _R , w _G , w _B , and w _E are defined as follows.

w _R = H _R / E _R
w _G = H _G / E _G
w _B = H _B / E _B
w _E = H _E / E _E
Method (6): When a primary color having a longer wavelength (lower energy) is made to have a higher output ratio, a primary color having a shorter wavelength (higher energy) is made to have a larger weighting coefficient for the primary color. By doing in this way, since the primary color with higher energy tends to deteriorate the display device (liquid crystal panel), the liquid crystal panel can be transmitted as much as possible to reduce the deterioration of the liquid crystal panel. Moreover, the calorific value can be reduced. In this case, the weighting factors w _R , w _G , w _B , and w _E are defined as follows.

w _R = 1 / E _R
w _G = 1 / E _G
w _B = 1 / E _B
w _E = 1 / E _E
Here, E _R , E _G , E _B , E _E = hc / λ, h is the Planck constant, c is the speed of light, and λ is the wavelength of light.

Method (7): When the output ratio is increased as the calorific value of the liquid crystal panel increases, the primary color having a larger calorific value of the liquid crystal panel increases the weighting coefficient of the primary color. By doing in this way, the emitted-heat amount can be made small. In this case, the weighting factors w _R , w _G , w _B , and w _E are defined as follows.

w _R = H _R
w _G = H _G
w _B = H _B
w _E = H _E
Here, H _R , H _G , H _B , and H _E are calorific values in the primary color RGBE liquid crystal panel.

Method (8): When a primary color with a large leak light of the liquid crystal panel has a higher output ratio, a primary color with a large leak light of the liquid crystal panel has a larger weighting coefficient for the primary color. When the liquid crystal panel deteriorates, the light cannot be switched sufficiently, and the amount of light (leakage light) that passes through the liquid crystal panel increases even during black display. Thus, the deterioration of the liquid crystal panel can be prevented and the life of the entire display device can be extended. In this case, the weighting factors w _R , w _G , w _B , and w _E are defined as follows.

w _R = Y _RK / Y _R
w _G = Y _GK / Y _G
w _B = Y _BK / Y _B
w _E = Y _EK / Y _E
Here, Y _RK , Y _GK , Y _BK , and Y _EK are leaked light in the primary color RGBE liquid crystal panel.

Example (1): Field-sequential LCD panel In a field-sequential LCD panel, one field is divided into four, and red, green, blue, and emerald backlight elements are sequentially turned on for each divided field. ing. The liquid crystal panel is controlled in accordance with the lighting timing of each backlight element, and one pixel is displayed in one field.

  In the case of such a field sequential type liquid crystal panel, if the output luminance of each primary color varies, periodic luminance flickering becomes conspicuous. For this reason, it is preferable that the light emission luminance of each primary color is averaged, and the method (1) is effective as a method of determining the weighting coefficient.

Specific example (2): In the case of a juxtaposed color mixing type liquid crystal panel In a juxtaposed color mixing type liquid crystal panel, a color filter of each color (red, green, blue, emerald) is juxtaposed to one pixel, and a white light backlight (for example, White LED) is irradiating the color filter. At this time, by controlling the liquid crystal panel, it is controlled which color filter transmits light through the liquid crystal panel. This controls the color in one pixel.

  Also in the case of the juxtaposed color mixing type liquid crystal panel, if the output luminance of each primary color varies, periodic luminance unevenness is conspicuous in the screen. For this reason, it is preferable that the light emission luminance of each primary color is averaged, and the method (1) is effective as a method of determining the weighting coefficient.

Specific Example (3): In the case of the juxtaposed color mixing type EL panel The juxtaposed color mixing type EL panel emits fluorescence by applying a voltage to an organic EL (Electro Luminescence) layer. Specifically, a voltage is applied using an ITO thin film as an anode and a cathode as a cathode. Here, four types of organic EL layers of red, green, blue, and emerald are used as light sources. Moreover, the color in each pixel is controlled by juxtaposing the light source of each color in one pixel and controlling the lighting state of the light source of each color.

  Even in the case of the juxtaposed color mixing type EL panel, if the output luminance of each primary color varies, periodic luminance unevenness is noticeable in the screen. For this reason, it is preferable that the light emission luminance of each primary color is averaged, and the method (1) is effective as a method of determining the weighting coefficient.

  Further, in the case of the juxtaposed color mixing type EL panel, each primary color is emitted from an individual light source, and the light source of each color deteriorates at a different speed depending on the color, thereby reducing the light emission amount. For this reason, the primary color with better luminous efficiency should have a higher output ratio (Method (2)), the primary color with a longer lifetime should have a higher output ratio (Method (3)), The smaller the primary color (the shorter the cumulative emission time), the larger the output ratio (method (4)), the product of the weighting factor of method (3) and the weighting factor of method (4) (Method (5)) is preferred. Therefore, the method (2), the method (3), the method (4), and the method (5) are also effective as the weighting coefficient determination method.

  According to the image processing apparatus of the present embodiment, since the output ratio of each primary color is determined based on the weighting coefficient of each primary color, the weighting coefficient of each primary color is appropriately set according to the situation, so that it is appropriate for the situation. The optimum output ratio can be selected, and appropriate color reproduction can be performed.

In particular,
(1) By increasing the weighting coefficient of a primary color that has a lower emission luminance, the emission luminance of each primary color can be averaged.
(2) By increasing the primary color weighting coefficient for a primary color with higher luminous efficiency, it is possible to increase the output ratio for a primary color with higher luminous efficiency.
(3) By increasing the weighting coefficient of a primary color that has a longer lifetime, the output ratio can be increased for a primary color that has a longer lifetime, and the lifetime of the entire display device can be increased.
(4) By increasing the primary color weighting coefficient for a primary color with a smaller cumulative emission amount (shorter cumulative emission time), the output ratio can be increased for a primary color with a lower cumulative emission amount (shorter cumulative emission time). The life of the entire display device can be lengthened by preferentially using the primary colors that are not frequently used.
(5) A primary color with a shorter wavelength (higher energy) can be set to have a higher output ratio for a primary color with a shorter wavelength by increasing the weighting coefficient of the primary color. Accordingly, the primary color with higher energy is more likely to deteriorate the display device (liquid crystal panel), so that the deterioration of the liquid crystal panel can be reduced by transmitting the liquid crystal panel as much as possible. Moreover, the calorific value can be reduced.
(6) By increasing the weighting coefficient of a primary color for a primary color with a larger calorific value of the liquid crystal panel, the output ratio can be increased as the calorific value of the liquid crystal panel is larger, and the calorific value can be reduced.
(7) By increasing the weighting coefficient of the primary color for the primary color with a large leakage light of the liquid crystal panel, the output ratio can be increased for the primary color with a large leakage light of the liquid crystal panel. When the liquid crystal panel deteriorates, the light cannot be switched sufficiently, and the amount of light (leakage light) that passes through the liquid crystal panel increases even during black display. Thus, the deterioration of the liquid crystal panel can be prevented and the life of the entire display device can be extended.

  Since the image processing apparatus according to one embodiment of the present invention described above has processing by a computer, it can take an embodiment as a recording medium in which a program for realizing the processing is recorded. Such recording media include CD-ROMs, magneto-optical disks, flexible disks, IC cards, ROM cartridges, computer internal storage devices (memory such as RAM and ROM), external storage devices, punch cards, barcodes, etc. Various types of computer-readable media such as printed matter on which codes are printed can be used.

Application of Image Processing Device 16 According to One Embodiment of the Present Invention to a Projector A case where the image processing device 16 according to one embodiment of the present invention is applied to a projector will be described with reference to FIGS.

Overall Configuration of Projector FIG. 3 is an explanatory diagram showing the overall configuration of the projector 10 as an embodiment of the present invention. The projector 10 includes an analog image input terminal 12, a digital image input terminal 14, three A / D converters 20, a video decoder (synchronization separation circuit) 22, a frame memory 24, a video processor 26, and a liquid crystal panel. A control unit 30, a liquid crystal panel 32, and a remote controller control unit 34 are provided. It is assumed that the frame memory 24 and the video processor 26 are integrated as one image processing integrated circuit 60.

  The projector 10 further includes an illumination device 50 for illuminating the liquid crystal panel 32 and a projection optical system 52 that projects the transmitted light that has passed through the liquid crystal panel 32 onto the screen S. The liquid crystal panel 32 is a transmissive liquid crystal panel, and is used as a light valve (light modulator) that modulates illumination light emitted from the illumination device 50.

  Although details will be described with reference to FIG. 4, the projector 10 has four liquid crystal panels 32 for the four primary colors of RGBE, and each circuit described later has a function of processing an image signal for the four primary colors. Have. The illumination device 50 includes a color light separation optical system that separates white light into four lights. Further, the projection optical system 52 has a combining optical system that combines the image light of the four colors to generate image light representing a color image. Note that the configuration of the optical system of such a projector (projection display device) is disclosed in, for example, Japanese Patent Application No. 8-352003 filed by the applicant of the present application, and the description thereof is omitted here.

  As the input image signal, either the analog image signal AV input to the analog image input terminal 10 or the digital image signal DV input to the digital image input terminal 12 can be selectively used. The analog image signal AV is converted by the A / D converter 20 into a digital image signal having three color image signal components.

  The image signal input to the video processor 26 is temporarily stored in the frame memory 24, read out from the frame memory 24, and supplied to the liquid crystal panel control unit 30. The video processor 26 performs various image processing on the input image signal during the writing and reading. The liquid crystal panel control unit 30 generates a control signal for controlling the liquid crystal panel 32 in accordance with the given image signal. The liquid crystal panel 32 modulates the illumination light in accordance with this control signal.

  The user can use the remote controller 40 to input setting values for various adjustments to be made on the entire image, such as input of weighting coefficients, contrast adjustment, and brightness adjustment. Although not shown, the projector 10 main body is also provided with keys and buttons for inputting various setting values.

FIG. 4 shows an internal configuration of the video processor 26, the liquid crystal panels 32 (32a to 32d), the illumination device 50, and the projection optical system 52 as an embodiment of the present invention. It is a block diagram which shows a structure. The video processor 26 includes a frame memory control unit 62, an image quality adjustment unit 68, and an image processing device 16 (corresponding to the image processing device 16 shown in FIG. 1).

  The frame memory control unit 62 writes the digital image signal DV0 supplied from the A / D converter 20 or the video decoder 22 shown in FIG. 1 into the frame memory 24 and controls to read the digital image signal from the frame memory 24. I do.

  The image quality adjustment unit 68 adjusts the contrast, brightness, sharpness, and the like of the entire image in accordance with user settings. Since the processing in the image quality adjustment unit 68 is well known, detailed description thereof is omitted.

  As described with reference to FIGS. 1 and 2, the image processing device 16 converts the input image signal of three colors composed of RGB into the output image signal of four primary colors composed of R′G′B′E ′. To do. Since the configuration and operation of the image processing device 16 are the same as those described with reference to FIGS. 1 and 2, the description thereof will be omitted.

  The liquid crystal panel control unit 30 performs the R liquid crystal panel 32a, the G liquid crystal panel 32b, and the B liquid crystal panel in accordance with the R′G′B′E ′ image signals given from the image processing device 16, respectively. A control signal for controlling the liquid crystal panel 32d for 32c and E is generated. The liquid crystal panels 32a to 32d modulate the illumination light in accordance with this control signal. Each of the liquid crystal panels 32a to 32d includes temperature detectors 63a to 63d and leakage light detectors 64a to 64d (corresponding to the “heat generation / leakage light detection unit 16h” in FIG. 1). The temperature data detected by the temperature detectors 63a to 63d and the data of leakage light detected by the leakage light detectors 64a to 64d are supplied to the weighting coefficient determination unit 16g of the image processing device 16.

  The illumination device 50 includes a lamp 50e, dichroic mirrors 50a to 50c, and a mirror 50d, and separates illumination light from the lamp 50e into four lights. That is, the illumination light from the lamp 50e is reflected by the dichroic mirror 50a toward the R liquid crystal panel 32a, and the illumination light transmitted through the dichroic mirror 50a is reflected by the dichroic mirror 50b toward the G liquid crystal panel 32b. The illumination light transmitted through the dichroic mirror 50b is reflected by the dichroic mirror 50c toward the B liquid crystal panel 32c, and the illumination light transmitted through the dichroic mirror 50c is reflected by the mirror 50d toward the E liquid crystal panel 32d. .

  Furthermore, the projection optical system 52 includes a mirror 54a, dichroic mirrors 54b to 54d, and a projection lens 56, and generates image light representing a color image by synthesizing four colors of image light. That is, the image light that has passed through the R liquid crystal panel 32 a is reflected by the mirror 54 a, then passes through the dichroic mirrors 54 b to 54 d and is projected onto the projection lens 56. Similarly, the image light transmitted through the G liquid crystal panel 32b is reflected by the dichroic mirror 54b, then transmitted through the dichroic mirrors 54c and 54d, and projected onto the projection lens 56, and then transmitted through the B liquid crystal panel 32c. After the image light is reflected by the dichroic mirror 54c, the image light is transmitted through the dichroic mirror 54d and projected onto the projection lens 56, and the image light transmitted through the E liquid crystal panel 32d is reflected by the dichroic mirror 54d and projected onto the projection lens 56. Projected on.

Weighting Method in Liquid Crystal Projector In the above liquid crystal projector, the weighting coefficient of the image processing device 16 is determined based on the temperature data detected by the temperature detectors 63a to 63d and the leaked light data detected by the leaked light detectors 64a to 64d. Weighting is performed by the unit 16g.

  In the case of a liquid crystal projector, there is a possibility that the liquid crystal panel (liquid crystal and polarizing plate) may be deteriorated by thermal energy generated when the light from the light source is blocked. For this reason, the primary color having a shorter wavelength (higher energy) should have a higher output ratio (method (6)), and the larger the heat generation amount of the liquid crystal panel, the larger the output ratio (method (7)). )) Is preferred. Therefore, the method (6) and the method (7) are effective as the weighting coefficient determination method.

  In the case of a liquid crystal projector, when the liquid crystal panel is deteriorated, light cannot be switched sufficiently, and the amount of light (leakage light) transmitted through the liquid crystal panel is increased even during black display. Therefore, it is preferable to indirectly measure the degree of deterioration of the liquid crystal panel from the magnitude of leakage light. Therefore, it is also preferable that the output ratio becomes larger for the primary color with a larger leakage light of the liquid crystal panel (method (8)).

  According to the projector according to the embodiment of the present invention, since the projector has the same configuration as the image processing device 16 shown in FIG. 1, by appropriately setting the weighting coefficient of each primary color according to the situation. Therefore, it becomes possible to select an optimum output ratio according to the situation, and appropriate color reproduction can be performed.

It is explanatory drawing which shows the whole structure of the image processing apparatus 16 as one Embodiment of this invention. 4 is a flowchart for explaining color conversion processing in the image processing apparatus 16; 1 is an explanatory diagram illustrating an overall configuration of a projector as an embodiment of the present invention. It is a block diagram which shows the internal structure of the video processor 26, the liquid crystal panel 32, the illuminating device 50, and the projection optical system 52 as one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Projector, 12 Analog image input terminal, 14 Digital image input terminal 16 Image processing apparatus, 16a YUV-> RGB conversion part, 16b γ conversion part 16c rgb-> XYZ conversion part, 16d r ₀ g ₀ b ₀ e ₀ calculation part 16e r ₁ g ₁ b ₁ e ₁ calculation unit, 16f luminance ratio determination unit, 16g weighting coefficient determination unit 16h calorific value / leakage light detection unit, 16j inverse γ conversion unit 16k emission amount / absorption amount integration unit, 18 display device, 20 A / D converter 22 video decoder, 24 frame memory, 26 video processor 30 liquid crystal panel control unit, 32 liquid crystal panel, 32a to 32d liquid crystal panel 34 remote controller control unit, 40 remote controller, 50 lighting device 50a to 50c dichroic mirror, 50d mirror , 50e Lamp 52 Projection optical system, 54a Mirror , 54b to 54d Dichroic mirror 56 Projection lens, 60 Image processing integrated circuit, 62 Frame memory control unit 63a to 63d Temperature detector, 64a to 64d Leakage light detector, 68 Image quality adjustment unit

Claims (14)

  The natural number N is larger than the natural number M, and is an image processing device that converts an M primary color input signal into an N primary color output signal,
  A first color conversion means for setting an output signal of (N−M) primary colors among N primary colors to a fixed value, and converting an M primary color input signal into an N primary color output signal;
  Means for setting a plurality of types of the fixed values and causing the first color conversion means to execute the conversion a plurality of times;
  Means for determining a weighting factor corresponding to a target output ratio of N primary colors;
  Second color conversion means for obtaining the N primary color output signal from the weighting coefficient and the result of the conversion executed a plurality of times by the first color conversion means;
  An image processing apparatus comprising:   The image processing apparatus according to claim 1,
  The fixed value is a minimum value or a maximum value that the output signal can take.
  Image processing device.   The image processing apparatus according to claim 1,
  The second color conversion means performs a weighted average of the results of the conversion executed a plurality of times by the first color conversion means so that a ratio of the N primary color output signals is closest to a ratio of the weighting coefficients;
  Image processing device. An image processing apparatus according to any one of claims 1 to 3 ,
For primary colors with lower emission luminance, increase the weighting coefficient for the primary color.
Image processing device. An image processing apparatus according to any one of claims 1 to 4 ,
For primary colors with better luminous efficiency, increase the weighting coefficient for the primary color.
Image processing device. An image processing apparatus according to any one of claims 1 to 5 ,
For a primary color with a long lifetime, increase the weighting coefficient of the primary color.
Image processing device. The image processing apparatus according to any one of claims 1 to 6 ,
The shorter the accumulated light emission time, the larger the weighting coefficient of the primary color.
Image processing device. An image processing apparatus according to any one of claims 1 to 7 ,
For the primary color with higher energy, the weighting coefficient of the primary color is increased.
Image processing device. The image processing apparatus according to any one of claims 1 to 8 ,
For the primary color with a larger calorific value of the image display device, the weighting coefficient of the primary color is increased.
Image processing device. An image processing apparatus according to any one of claims 1 to 9 ,
In the image display device, the primary color with a large leak light has a larger weighting coefficient for the primary color.
Image processing device.   An image projection apparatus for converting a primary color input signal into an N primary color output signal, wherein the natural number N is larger than the natural number M,
  A first color conversion means for setting an output signal of (N−M) primary colors among N primary colors to a fixed value, and converting an M primary color input signal into an N primary color output signal;
  Means for setting a plurality of types of the fixed values and causing the first color conversion means to execute the conversion a plurality of times;
  Means for determining a weighting factor corresponding to a target output ratio of N primary colors;
  Second color conversion means for obtaining the N primary color output signal from the weighting coefficient and the result of the conversion executed a plurality of times by the first color conversion means;
  An image projection apparatus comprising:   An image processing method in which a natural number N is larger than a natural number M, and an M primary color input signal is converted into an N primary color output signal,
  A first color conversion step of setting an output signal of (N−M) primary colors out of N primary colors to a fixed value and converting an M primary color input signal to an N primary color output signal;
  A step of setting a plurality of types of the fixed value and causing the conversion to be performed a plurality of times by the first color conversion step;
  Determining a weighting factor corresponding to the target output ratio of the N primary colors;
  A second color conversion step of obtaining the N primary color output signal from the weighting coefficient and the result of the conversion executed a plurality of times by the first color conversion step;
  An image processing method comprising:   A program for causing a computer to execute image processing for converting an M primary color input signal into an N primary color output signal, where the natural number N is larger than the natural number M,
  A first color conversion process of setting an output signal of (N−M) primary colors among N primary colors to a fixed value and converting an M primary color input signal to an N primary color output signal;
  A process of setting a plurality of types of the fixed values and causing the conversion to be performed a plurality of times by the first color conversion process;
  A process for determining a weighting coefficient corresponding to the target output ratio of the N primary colors;
  A second color conversion process for obtaining the N primary color output signal from the weighting factor and the result of the conversion executed a plurality of times by the first color conversion process;
  A program that causes a computer to execute. A natural number N is larger than the natural number M, a computer-readable recording medium recording a program for causing a computer to execute image processing for converting an M primary color input signal into an N primary color output signal,
A first color conversion process of setting an output signal of (N−M) primary colors among N primary colors to a fixed value and converting an M primary color input signal to an N primary color output signal;
A process of setting a plurality of types of the fixed values and causing the conversion to be performed a plurality of times by the first color conversion process;
A process for determining a weighting coefficient corresponding to the target output ratio of the N primary colors;
A second color conversion process for obtaining the N primary color output signal from the weighting factor and the result of the conversion executed a plurality of times by the first color conversion process;
A computer-readable recording medium on which a program for causing a computer to execute is recorded .

Images