JP2007241193A - Image display controller, projector and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display controller capable of performing arithmetic processing with ease and high precision to a multi-bit video signal. <P>SOLUTION: The image display controller controls an image display apparatus provided with a luminance modulation element and a color modulation element. A MAX selecting circuit 11 extracts the maximum value from among each signal value of RGB components in an input video signal, and outputs it as the maximum signal value. A floating point arithmetic circuit 12 changes the maximum signal value into a floating point format, and outputs it as a floating maximum signal value. A degeneracy LUT 13 includes a degeneracy table showing correspondence between the floating maximum signal values and control values of the luminance modulation element, and reads out the control value of the luminance modulation element corresponding to the floating maximum signal value from the degeneracy table, and outputs it as a luminance modulation control value Mr. A correction circuit 15 corrects each signal value of RGB components making them correspond to the luminance modulation control value, and outputs it as a color modulation control value Br. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an HDR (High Dynamic Range) display technology that uses multi-bit and high-precision data and displays near real images on a display, and performs image display with high brightness / high contrast in accordance with the HDR format. The present invention relates to a display control device, a projector, and a control method thereof.

In recent years, in the field of computer graphics, HDR rendering technology has been developed, and the calculation of the displayed color is not performed on each of the 8 colors (16.77 million colors) of the three primary colors R (red), G (green), and B (blue). High-precision color calculation is performed using multi-bits (16 bits or the like), and an image close to the state actually seen is generated.
In addition, as a display for HDR display, a color modulation optical element that modulates the luminance of the three primary colors of incident light according to image data, and the luminance of all wavelengths of light incident from the RGB color modulation optical elements are modulated. A two-modulation projection display device has been developed in which a luminance modulation optical element is optically arranged in series and projected onto a screen.

  As a method for obtaining the control value of the liquid crystal panel used as the color modulation optical element and the luminance modulation optical element, when obtaining the control value of the luminance liquid crystal panel from the input video signal, the input video signal is subjected to inverse gamma correction. The maximum value of the RGB component is set as the control value of the luminance liquid crystal panel, and the control value of the color liquid crystal panel is obtained by dividing the value of each of the RGB components corrected by inverse γ by the control value of the luminance liquid crystal panel. A control value of the color liquid crystal panel is calculated so as to be proportional to the value (see, for example, Patent Document 1).

  As another method for obtaining the control value of the liquid crystal panel, first, each RGB in the input video signal is normalized, and a luminance signal is calculated from the normalized RGB signal values. Then, each normalized RGB component is divided by the square root of the luminance signal, the maximum value in the division result is obtained, and this value is used as the control value of the luminance panel. Here, when the maximum value of the division result is larger than a preset threshold value, clipping processing of the maximum value is performed, and the value of the threshold value is output as the control value of the luminance panel.

Next, a result obtained by dividing the normalized RGB signal value by the obtained control value of the luminance panel is used as a control value of the color liquid crystal panel corresponding to each of RGB (for example, Patent Documents). 2).
Japanese Patent Laid-Open No. 06-167690 JP 2004-242136 A

  However, in the method for obtaining the control value shown in Patent Document 1 and Patent Document 2, there is a problem in that the arithmetic processing becomes complicated as the number of bits increases, and the cost of the processing circuit increases.

  The present invention has been made in view of such circumstances, and an object of the present invention is to set control values of a luminance modulation optical element and a color modulation optical element that perform image display in an HDR format (two modulation optical system) as a multi-bit. An object of the present invention is to provide an image display control device, a projector, and a control method therefor that can perform calculation processing with high accuracy on a video signal with a simple circuit configuration.

  The present invention has been made to solve the above-described problems, and an image display control device according to the present invention is an image display control device that controls an image display device including a luminance modulation element and a color modulation element, The maximum value is extracted from the signal values of each of a plurality of color components in the input video signal, and is output as the maximum signal value. The maximum signal value is converted into a floating-point format, and the maximum floating value is obtained. A floating-point conversion unit that outputs as a signal value, and a degeneration table that indicates correspondence between the maximum floating-point signal value and a control value of a luminance modulation element, and the maximum floating-point signal value output from the floating-point conversion unit The luminance modulation element control value corresponding to the degeneration table, the degeneration unit for outputting as a luminance modulation control value, and corresponding to the luminance modulation control value, correcting the signal value of each of the plurality of color components, color And having a color correction unit for outputting a tone control value.

  An image display apparatus control method according to the present invention is a control method for controlling an image display apparatus including a luminance modulation element and a color modulation element, and the signal value of each of a plurality of color components in an input video signal. A first step of extracting a maximum value from the output and outputting the maximum signal value as a maximum signal value; a second step of converting the maximum signal value into a floating-point format and outputting the value as a floating maximum signal value; and the image display device Has a degeneration table indicating the correspondence between the floating maximum signal value and the control value of the luminance modulation element, and the control value of the luminance modulation element corresponding to the floating maximum signal value output in the second step Is read from the degeneration table and output as a luminance modulation control value, and a signal value of each of a plurality of color components is corrected in correspondence with the luminance modulation control value, and output as a color modulation control value. With 4 processes And wherein the door.

  As a result, the image display control apparatus (or method) of the present invention, when converting a multi-bit video signal to a luminance modulation control value with a small number of bits, temporarily reduces the number of bits after reducing the number of bits to a floating-point format. Since conversion is performed using an uptable, it is possible to perform arithmetic processing with high accuracy with a simple circuit configuration.

The image display control device according to the present invention is the image display control device described above, wherein the degeneration table has a characteristic of a control value of the luminance modulation element with respect to the floating maximum signal value of γ1.0 or less. And
As a result, the image display control device of the present invention has a degeneration table characteristic of γ1.0 or less, and therefore, among the plurality of color components, the color having the maximum signal value is not controlled only by the luminance modulation element, In addition to the luminance modulation element, the adjustment range by the color modulation element can be afforded, color reproducibility is improved, and a high-quality image can be expressed.

The image display control device according to the present invention is the above-described image display control device, wherein the color correction unit is configured to transmit the light transmittance in the correction target color light of the luminance modulation element driven by the luminance modulation control value and the luminance modulation control value. A correction coefficient table indicating the correspondence between the reciprocal value and the value expressed in the floating-point format, and reading out the value corresponding to the luminance modulation control value output from the degeneration unit from the correction coefficient table, and the correction coefficient signal A correction coefficient part output as a value, and a result obtained by multiplying the correction coefficient signal value output from the correction coefficient part by the signal value of each of a plurality of color components by a floating-point operation is converted into an integer value and output as a color modulation control value And a multiplication unit.
As a result, the image display control apparatus of the present invention can generate the color modulation control value with high accuracy while suppressing the circuit scale by making the multiplication portion of the correction coefficient and the video signal, which require accuracy, the floating point format. .

The image display control device according to the present invention is the above-described image display control device, wherein when the multiplication result is an integer value in the color correction unit, when the multiplication result overflows, a predetermined upper limit value is set. A clipping process is performed.
As a result, the image display control device of the present invention can prevent an illegal calculation such as an overflow due to a measurement error or a calculation error, and generate a highly realistic color modulation control value.

The image display control device according to the present invention is any one of the above-described image display control devices, wherein the degeneration unit outputs the modulation degree characteristic of the luminance modulation element with respect to the luminance modulation control value to be γ1.0 or less. A luminance characteristic adjusting unit that converts the luminance modulation control value to obtain a control value for the luminance modulation element is provided.
As a result, the image display control apparatus of the present invention is not controlled only by the luminance modulation element, even for the color having the maximum signal value among the RGB components, and there is a margin in the adjustment range by the color modulation element in addition to the luminance modulation element. Color reproducibility and high-quality images can be expressed.

The image display control device of the present invention is any one of the image display control devices described above, wherein the color correction unit outputs the modulation degree characteristic of the color modulation element with respect to the color modulation control value to be γ2.2. A color characteristic adjustment unit is provided that converts the color modulation control value into a control value for the color modulation element.
As a result, the image display control apparatus of the present invention can utilize the control know-how of the conventional color modulation element, and can uniformly adjust the modulation degree characteristic of each color modulation element with respect to the color modulation control value to γ2.2. The display characteristics of each image display device can be made uniform with high accuracy without adjusting the generation of the modulation control value to the characteristics of the individual color modulation elements.

  A projector according to the present invention includes any one of the image display control devices described above.

Hereinafter, an image display control apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the concept of the image display control apparatus according to the embodiment. Here, the signal values Ri, Gi, Bi of RGB (red, green, blue) components are each input with 16 bits as the signal values of the color components in the input video signal, and the liquid crystal lights for luminance modulation and color modulation are used. The brightness control value Mr and the color modulation control values Rr, Gr, Br for driving the bulb will be described as 10 bits.
FIG. 1 shows a color liquid crystal panel (determined from a luminance modulation control value which is a control value of a luminance liquid crystal panel (a liquid crystal light valve (L / V) 14 described later)) and a signal value Br of a B component as a representative of RGB components ( A configuration example is shown in which a color modulation control value of a liquid crystal light valve (L / V) 16), which will be described later, is obtained and the liquid crystal light valves 14 and 16 are driven. In FIG. 1, the color modulation control values of the color liquid crystal panel corresponding to the R and G components other than the B component are not described, but are the same as the processing for the color modulation control value Br shown in FIG.

11 is a MAX selection circuit (maximum) that selects the maximum signal value (that is, gradation) from among the signal values Ri, Gi, and Bi of the RGB components of a certain pixel and outputs them as the maximum signal value. Value selection unit).
12 is a floating point conversion circuit (floating point conversion unit) that, when the maximum signal value is input, converts it to a floating point format consisting of 12 bits of an exponent part of 3 bits and a mantissa part of 9 bits and outputs a floating maximum signal value. It is. Since the floating point conversion circuit 12 can be realized by a bit comparator and a barrel shift circuit, it can be configured by a very small circuit.
13 has a degeneration table indicating the correspondence between the floating maximum signal value (exponent part 3 bits, mantissa part 9 bits) and the luminance modulation control value of the 10-bit integer value for controlling the liquid crystal light valve 14. This is a reduction LUT (Look Up Table) (degeneration unit) that reads out and outputs the luminance modulation control value Mr corresponding to the input floating maximum signal value from the reduction table. The degeneration table stores the luminance modulation control value Mr so that the characteristic of the luminance modulation control value Mr with respect to the input floating maximum signal value becomes a characteristic of γ1.0 or less.

Here, by setting the characteristic of the luminance modulation control value Mr with respect to the floating maximum signal value to a value smaller than γ1.0, the transmittance in the liquid crystal light valve 16 is also obtained for the color selected as the maximum value by the MAX selection circuit 11. The adjustment range can be increased, color reproducibility is improved, and high-quality images can be expressed.
Further, in this way, when obtaining the 10-bit luminance modulation control value from the 16-bit maximum signal value selected by the MAX selection circuit 11, after converting it into the floating-point format and reducing the number of bits (here In this case, the calculation accuracy can be kept high while suppressing the enlargement of the lookup table due to the increase in the number of bits.

19 has a luminance table showing the correspondence between the numerical value of the luminance modulation control value Mr and the luminance control value VT for driving the liquid crystal light valve 14, and the luminance control corresponding to the inputted luminance modulation control value Mr. This is a luminance LUT (luminance characteristic adjustment unit) that generates the luminance control value VT by reading the value VT from the luminance table and outputting it. The luminance table shows the characteristic of the transmittance Ls of the liquid crystal light valve 14 with respect to the inputted luminance modulation control value Mr based on the result of measuring the characteristic of each liquid crystal light valve 14 as shown in the graph 102. A brightness control value VT corrected to have a characteristic equal to or lower than the power is stored.
Reference numeral 20 includes a D / A converter, which converts the digital brightness control value VT output from the brightness LUT 19 into an analog voltage value and outputs the analog voltage value to the liquid crystal light valve 14. Is a driver circuit (Dec Driver) that performs luminance modulation processing on light incident on the liquid crystal light valve 14.

  15 corrects the input signal value Bi of the B component in the input video signal in accordance with the luminance modulation control value Mr determined by this video signal by the equation (5) described later, and the color modulation control value Br ( Rr and Gr are also the same correction circuit. For example, the correction circuit 15 includes a correction LUT (correction coefficient unit) 51 and a multiplication circuit (multiplication unit) 52 as shown in FIG. In the pixel unit signal processing performed in the circuits of FIGS. 1 and 2, the color modulation control value Br and the luminance modulation control value Mr input to the color LUT 17 and the luminance LUT 19 must be input at the same timing for each pixel. is there. Therefore, in practice, it is necessary to delay the time required for the calculation by the correction circuit 15 to input the luminance modulation control value Mr immediately before it is input to the luminance LUT 19. Further, from the viewpoint of timing control for accurately performing the arithmetic processing, it is necessary to input the output from the correction LUT 51 and the input signal Bi to the multiplication circuit 52 at the same timing in the correction circuit 15 of FIG. That is, in the correction circuit 15, the input timing of the luminance modulation control value Mr is the same as the input timing of the processing of the MAX selection circuit 11, the fixed point conversion circuit 12, and the degenerate LUT 13 with respect to the input signal value Bi. There is a delay. For this reason, for the multiplication process in the multiplication circuit 52, it is necessary to synchronize the input timing of the input signal value Bi and the luminance modulation control value Mr with the multiplication timing. As described above, in the present embodiment, the timing adjustment of about several clocks between the circuits can be sufficiently analogized to perform the processing in units of pixels as can be understood from the processing flow. The explanation of adjustment is omitted.

  Reference numeral 51 denotes a correction coefficient table that indicates the correspondence between the luminance modulation control value Mr and the correction coefficient value MB. A correction LUT that outputs a correction coefficient value MB used in a later-described multiplier circuit 52 in a floating-point format. is there. This correction coefficient value MB is a value obtained by raising the reciprocal of the transmittance characteristic g (Mr) of the liquid crystal light valve 14 to the power of 1 / 2.2.

  Here, the transmittance characteristic “g (Mr)” of the liquid crystal light valve 14 assumes that the transmittance characteristic “h (Br)” of the liquid crystal light valve 16 is a characteristic of γ2.2. It needs to be 2.2. The transmittance characteristic “g (Mr)” of the liquid crystal light valve 14 can also be a characteristic of γ2.2.

  However, when the transmittance characteristic “g (Mr)” of the liquid crystal light valve 14 is γ2.2, the transmittance characteristic of the entire two-modulation system is also γ2.2, and the transmittance of the liquid crystal light valve 14 that performs luminance modulation is also used. In particular, regarding the color selected as the maximum value, it means that only the maximum transmittance portion of the liquid crystal light valve 14 that controls the transmittance for each color is used. This greatly reduces the amount of transmitted light on the luminance modulation side, so that there is less adjustment margin on the color side in the bright part, resulting in a decrease in color reproduction performance.

  Therefore, if the transmittance characteristic “g (Mr)” of the liquid crystal light valve 14 is γ <1, as described above, there is a margin in the adjustment range of the transmittance in the liquid crystal light valve 16, and the color reproducibility is also high. Therefore, a high-quality image can be expressed.

The multiplication circuit 52 performs multiplication of the input signal value Bi and the correction coefficient value MB by multiplication processing in floating point arithmetic. Further, the multiplication circuit 52 converts the floating-point operation result into a 10-bit integer. As an important process in this conversion, there is a clipping process.
That is, due to errors in measurement of the transmittance characteristics of the liquid crystal light valve 14 for creating the luminance table and the correction table, and calculation errors, the bright part (when the gradation is high and the transmittance of the liquid crystal light valve is set high) ), The floating-point multiplication result may be an integer value exceeding 10 bits. That is, in the multiplication circuit 52, when the floating-point multiplication result becomes an operation result exceeding 10 bits at the time of conversion, that is, when the data value exceeds the storable data value, it appears to be a small value. For this reason, clipping is performed with the maximum integer value represented by 10 bits, that is, 1023 as the upper threshold, and the floating-point multiplication result exceeding this threshold as 1023. Here, the multiplication circuit 52 has a carry flag, and detects whether or not the threshold has been exceeded by detecting this flag.

The color LUT 17 has a color table indicating the correspondence between the numerical value of the color modulation control value Br and the color control value VTC for driving the liquid crystal light valve 16, and the color corresponding to the input color modulation control value Br. The color control value VTC is generated by reading the control value VTC from the color table and outputting it. The color table shows the transmittance characteristic of the liquid crystal light valve 16 with respect to the input control value Br, as shown in the graph 101, corresponding to the numerical value of the input control value Br. Is stored as a color control value VTC corrected so as to have a transmittance characteristic of γ2.2.
Reference numeral 18 includes a D / A converter, which converts the digital color control value VTC output from the color LUT 17 into an analog voltage value and outputs the analog voltage value to the liquid crystal light valve 16. Is a driver circuit (Dec Driver) that performs color modulation processing on the light incident on the liquid crystal light valve 16.

Next, a basic algorithm for determining a control value to be output corresponding to an input control value stored in each of the luminance LUT 19, the color LUT 17, the degenerate LUT 13, and the correction LUT 52 will be described with reference to FIG. To do. Here, as an example, the processing will be described by taking the case of the B component in the RGB component of the video signal, that is, the case of blue.
As described above, the liquid crystal light valve 16 is a liquid crystal light valve that controls modulation of the B component (Blue), and the liquid crystal light valve 14 modulates luminance (light of all components of R, G, and B). It is a liquid crystal light valve to be controlled.

Here, the relationship between the control value Br of the liquid crystal light valve 16 and the liquid crystal light valve 16 transmittance Lp is expressed by the following equation (1).
Lp = h (Br) (1)
Similarly, the relationship between the control value Mr of the liquid crystal light valve 14 and the transmittance Ls of the liquid crystal light valve 14 is expressed by the following equation (2).
Ls = g (Mr) (2)

Further, as a whole of the two-modulation optical system (for example, HDR display), the luminance value of light incident on the liquid crystal light valve 16 (color modulation side) from the light source is Hi, and the light is emitted from the liquid crystal light valve 14 (luminance modulation side). Assuming that the luminance value of the output light is Ho, the total characteristic of the liquid crystal light valve 16 and the liquid crystal light valve 14 is expressed by the following equation (3).
Ho / Hi = Lp × Ls = f (Bi, Mr) (3)
And when calculating | requiring about control value Br from (1), (2) and (3) Formula,
Since Lp × Ls = h (Br) × g (Mr) = f (Bi, Mr),
Br = h ⁻¹ × {f (Bi, Mr) × (1 / g (Mr)}} (4)
It becomes.
This is because correction characteristics (correction coefficient values) used in the correction circuit 15 are determined by determining overall transmittance characteristics in the two-modulation optical system, that is, transmittance characteristics corresponding to the control values of the liquid crystal light valves 16 and 14. ) Is uniquely determined.

Here, since the video signal input to the image display control device is a signal assuming that the image display device has a γ characteristic of 2.2, it is input as a signal having a γ characteristic of 0.45. Therefore, as shown in the graph 103, it is necessary that f (Bi, Mr) = Lp × Ls = Ho / Hi, which is a total transmittance characteristic on the image display apparatus side, has a characteristic of γ = 2.2. is there.
Therefore, in the signal processing algorithm in this embodiment, it is necessary to measure the transmittance characteristics of each of the liquid crystal light valves 14 and 16 and match the transmittance characteristics with respect to the control values of these liquid crystal light valves among the respective display devices. There is. Here, the transmittance characteristic of the liquid crystal light valve 16 is desirably γ = 2.2 because conventional control know-how (correction method and modulation method in one modulation optical system) can be used as it is.

Therefore, from equation (1)
Lp = h (Br) = Br ^2.2
Also, from equation (3)
f (Bi, Mr) = Bi ^2.2
From these equations and equation (4),
Br = {Bi ^2.2 × (1 / g (Mr))} ^1/2.
= Bi × (1 / g (Mr)) ^{1 / 2.2} (5)
This equation (5) is the correction content in the correction circuit 15.
Since the luminance modulation control value Mr is the maximum value in the RGB component of the input video signal, the relationship between the signal value Bi in the RGB component (the same applies to other Ri and Gi) and the following equation (6) is there.
Bi ≦ Mr (6)

In each of the above-described expressions, the calculation result Ans needs to be within the range of 0 ≦ Ans ≦ 1, and therefore, the relationship between the following expressions (7) and (8) can be obtained from the expressions (5) and (6).
Bi ^2.2 × (1 / g (Mr)) ≦ 1 (7)
g (Mr) ≧ Bi ^2.2 (8)
From these equations (7) and (8), it can be seen that the g value of g (Mr) may be 2.2 or less. However, as described above, in order to improve color reproducibility, here, the control value Mr and the transmittance of the liquid crystal light valve 14 in the luminance table are modulated so that the γ value of g (Mr) is 1 or less. The correspondence with the brightness control value VT to be set is set.

  Next, the operation of this image display control apparatus will be described. For example, it is assumed that a signal with Ri of “10000”, Gi of “20000”, and Bi of “50000” is input to the image display control apparatus as a video signal of a certain pixel. The MAX selection circuit 11 extracts “50000” of Bi, which is the maximum value, from these. Upon receiving “50000”, the floating point conversion circuit 12 converts this to a floating point with a mantissa part 9 bits and an exponent part 3 bits and outputs it as a floating maximum signal value. Here, since “50000” is “1100001101010000” in binary, the mantissa part of the floating maximum signal value is “110000110” and the exponent part is “111”. The degeneration LUT 13 reads the luminance modulation control value corresponding to this floating maximum signal value from the degeneration table. Here, it is assumed that “110010000” is stored in the degeneration table as a corresponding value, and this value is read out. The luminance modulation control value is input to the luminance LUT 19 as it is. The luminance LUT 19 refers to the luminance table, converts the input value to the luminance control value VT, and outputs it to the driver circuit 20. The driver circuit 20 controls the transmittance of the corresponding pixel of the liquid crystal light valve 14 based on the input luminance control value VT.

  On the other hand, the luminance modulation control value read by the degenerate LUT 13 is also input to the correction circuit 15. When receiving the luminance modulation control value “110010000” (Mr = 784), the correction LUT 51 of the correction circuit 15 reads the corresponding correction coefficient value MB from the correction table. The transmittance gb for blue light in the state where the luminance side liquid crystal panel is driven with the luminance control value VTb with respect to the luminance modulation control value (Mr = 784) is “0.8932”. Therefore, the correction coefficient value MB = 1 / gb = 1.1196 corresponding to Mr is stored. This can be expressed as a mantissa part “1.00011110” and an exponent part “0” in binary numbers in floating point format. The correction coefficient value MB is input to the multiplication circuit 52. When the multiplication circuit 52 receives the signal value Bi “1100001101010000” of the B component of the video signal together with the correction coefficient value MB, the multiplication circuit 52 multiplies the correction coefficient value MB and the signal value Bi to “1101101000110011”, and the higher 10 bits. Extract to obtain “1101101000”. This is output to the color LUT 17 as the color modulation control value Br. The color LUT 17 refers to the color table, converts the input value to a color control value VTC, and outputs the color control value VTC to the driver circuit 18. The driver circuit 18 controls the transmittance of the corresponding pixel of the liquid crystal light valve 16 based on the input color control value VTC.

In the present embodiment, the liquid crystal light valves 14 and 16 that control the amount of light by controlling the transmittance of the liquid crystal panel have been described as being used as light valves (modulating elements). However, the amount of light can be controlled by controlling reflection. A DMD (Digital Micromirror Device) or the like that controls the light may be used as the light valve.
Further, in the present embodiment, it has been described that color modulation is performed by the first-stage liquid crystal light valve 16 and luminance modulation is performed by the second-stage liquid crystal light valve 14, but in the first and second stages. The modulation performed may be reversed, and the luminance modulation may be performed by the first-stage liquid crystal light valve, and the color modulation may be performed by the second-stage liquid crystal light valve.

  In FIG. 1, only the B component of the video signal is shown and the R component and the G component are omitted for simplicity of explanation, but a schematic configuration including these R component, G component and delay circuit is shown in FIG. In the figure, parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted. Reference numeral 17r denotes a red LUT which is an R component color LUT. Reference numeral 17g denotes a green LUT which is a G component color LUT. Reference numeral 17b denotes a blue LUT which is a B component color LUT. Reference numerals 18r, 18g, and 18b denote driver circuits that drive the R component, G component, and B component liquid crystal light valves 16r, 16g, and 16b, respectively.

Reference numerals 51r, 51g, and 51b denote correction LUTs for calculating correction coefficient values of the R component, the G component, and the B component, respectively. Reference numerals 52r, 52g, and 52b denote multiplication circuits for multiplying the R component, G component, and B component signal values Ri, Gi, Bi and the correction coefficient values to obtain the color modulation control values Rr, Gr, Br, respectively. The correction LUT 51b and the multiplication circuit 52b correspond to the correction LUT 51 and the multiplication circuit 52 in FIG.
Reference numerals 30r, 30g, and 30b denote delay circuits for synchronizing the input timings of the signal values Ri, Gi, and Bi and the correction coefficient values in the multiplication circuits 52r, 52g, and 52b. 31 is a delay circuit for synchronizing the input timing of the luminance modulation control value Mr to the luminance LUT 19 and the input timing of the color modulation control values Rr, Gr, Br to the color LUTs 17r, 17g, 17b.

  As an example of a display device using the image display control device, a configuration of a projection display device will be briefly described. FIG. 4 shows a configuration example of a projection display device, that is, a projector. The projection display device includes a light source 510, a uniform illumination unit 520 that uniformizes a luminance distribution of light incident from the light source 510, and three primary colors (R, G, and R) among incident light incident from the uniform illumination unit 520. B) a color modulation unit 530 that modulates the luminance of each, a relay lens 540 that relays the light incident from the color modulation unit 530, and a liquid crystal luminance panel 550 that modulates the luminance in the entire wavelength region of the light incident from the relay lens 540. And a projection lens 560 that projects light incident from the liquid crystal luminance panel 550 onto a screen (not shown).

  The light source 510 includes a lamp 511 such as a high-pressure mercury lamp, and a reflector 512 that reflects light emitted from the lamp 511. The luminous flux emitted from the light source 510 is made uniform by uniform illumination means 520 in which a first fly eye lens 521, a second fly eye lens 522, and the like are sequentially installed.

  The light with uniform polarization emitted from the uniform illumination means 520 enters the color modulation unit 530 and is separated into three primary colors (R, G, B), and the color modulation control system shown in FIG. 1 generates each color component. The liquid crystal color panel 531 (liquid crystal light valve 16r corresponding to the color component R) and 532 (liquid crystal light corresponding to the color component G) are converted into voltage values by the driver circuit 18 and modulated by the control signal. Bulbs 16g) and 533 (liquid crystal light valve 16b corresponding to color component B) are modulated and emitted.

  The modulated three primary color lights (R, G, B) are combined by the cross dichroic prism 534 and output to the relay lens 540. Here, the liquid crystal color panel 531 is for the R component, the liquid crystal color panel 532 is for the G component, the liquid crystal color panel 533 is for the B component, and the dichroic mirror 535 is for transmitting the R component light. The dichroic mirror 536 transmits B component light. The liquid crystal color panel 531 is provided with a reflection mirror 537, and the liquid crystal color panel 533 is provided with a relay lens 538 and two reflection mirrors 539a and 539b.

The modulated light emitted from the relay lens 540 enters the other liquid crystal luminance panel 550 (the liquid crystal light valve 14 for luminance modulation), and is emitted after receiving the second modulation. In the liquid crystal luminance panel 550, the luminance of the entire wavelength region of incident light is modulated by the luminance control value VT, and the modulated light is emitted to the projection lens 560 and projected onto a screen (not shown) by the projection lens 560.
In this way, the projection image is formed by modulating each light modulation element (liquid crystal luminance panel 550 and liquid crystal color panels 531, 532, and 533) optically arranged in series on a pixel basis.

  In order to realize the functions of the color control value and luminance control value generation processing in the MAX selection circuit 11, floating point conversion circuit 12, degeneration LUT 13, correction circuit 15, luminance LUT 19, and color LUT 17 in the image display control apparatus in FIG. The computer program is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed to generate a color control value and a luminance control value from the video signal. Good. The “computer system” here includes an OS and hardware such as peripheral devices. The “computer system” includes a WWW system provided with a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within a scope not departing from the gist of the present invention.

  The present invention is an image display control apparatus that controls a modulation optical element of a two-modulation projection type display apparatus, and is used for an image display control apparatus that controls a modulation optical element based on a multi-bit video signal such as 16 bits. Although it is suitable, it is not limited to this.

It is a block diagram which shows the structure of the image display control apparatus by one Embodiment of this invention. 3 is a block diagram showing a schematic configuration of a correction circuit 15 in the same embodiment. FIG. FIG. 2 is a block diagram showing a schematic configuration of an image display control device including RGB components and a delay circuit in the same embodiment. It is a figure explaining schematic structure of the projection type display device in the embodiment.

Explanation of symbols

11 ... MAX selection circuit 12 ... Floating point conversion circuit 13 ... Degenerate LUT
14 ... L / V (Liquid Crystal Light Valve)
15 ... Correction circuit 16, 16r, 16g, 16b ... L / V (liquid crystal light valve)
17 ... Color LUT
17r ... Red LUT
17g ... Green LUT
17b ... Blue LUT
18, 18r, 18g, 18b ... Dec Driver (driver circuit)
19 ... Luminance LUT
20 ... Dec Driver (driver circuit)
30r, 30g, 30b ... delay circuit 31 ... delay circuit 51, 51r, 51g, 51b ... correction LUT
52, 52r, 52g, 52b ... multiplication circuit 510 ... light source 511 ... lamp 512 ... reflector 520 ... uniform illumination means 521 ... first fly eye lens 522 ... second fly eye lens 530 ... color modulators 531, 532, 533 ... liquid crystal Color panel (liquid crystal light valves 16r, 16g, 16b)
534 ... Cross dichroic prism 535, 536 ... Dichroic mirror 537 ... Reflection mirror 538 ... Relay lens 539a, 539b ... Reflection mirror 540 ... Relay lens 550 ... Liquid crystal luminance panel (liquid crystal light valve 14)
560 ... Projection lens

Claims (8)

An image display control device for controlling an image display device comprising a luminance modulation element and a color modulation element,
A maximum value selection unit that extracts a maximum value from signal values of each of a plurality of color components in the input video signal and outputs the maximum value as a maximum signal value;
A floating point conversion unit for converting the maximum signal value into a floating point format and outputting the maximum signal value as a floating maximum signal value;
A degeneration table indicating correspondence between the floating maximum signal value and the control value of the luminance modulation element, and the control value of the luminance modulation element corresponding to the floating maximum signal value output from the floating point conversion unit is A degeneration unit that reads from the degeneration table and outputs as a luminance modulation control value;
An image display control apparatus comprising: a color correction unit that corrects signal values of each of the plurality of color components in correspondence with the luminance modulation control value and outputs the correction values as color modulation control values.   The image display control apparatus according to claim 1, wherein the degeneration table has a characteristic of a control value of a luminance modulation element with respect to the floating maximum signal value of γ1.0 or less. The color correction unit
A correction coefficient table indicating correspondence between the luminance modulation control value and a value expressed in floating-point format of an inverse value of light transmittance of the correction target color light of the luminance modulation element driven by the luminance modulation control value; A correction coefficient unit that reads a value corresponding to the luminance modulation control value output by the degeneration unit from the correction coefficient table and outputs the value as a correction coefficient signal value;
And a multiplication unit that multiplies the correction coefficient signal value output from the correction coefficient unit by the signal value of each of the plurality of color components by a floating-point operation, and outputs the result as a color modulation control value. The image display control device according to claim 1 or 2.   4. The image display control apparatus according to claim 3, wherein when the multiplication result overflows in the color correction unit when the multiplication result is an integer value, clipping processing is performed at a preset upper limit value. . A luminance characteristic adjustment unit that converts the luminance modulation control value output from the degeneration unit to obtain a control value of the luminance modulation element so that the modulation degree characteristic of the luminance modulation element with respect to the luminance modulation control value is γ1.0 or less. The image display control device according to any one of claims 1 to 4, further comprising: A color characteristic adjustment unit that converts the color modulation control value output from the color correction unit to obtain a control value of the color modulation element so that a modulation degree characteristic of the color modulation element with respect to the color modulation control value is γ2.2. The image display control device according to any one of claims 1 to 5, further comprising:   A projector comprising the image display control device according to any one of claims 1 to 6. A control method for controlling an image display device comprising a luminance modulation element and a color modulation element,
A first process of extracting a maximum value from signal values of each of a plurality of color components in an input video signal and outputting the maximum value as a maximum signal value;
A second step of converting the maximum signal value to a floating-point format and outputting as a floating maximum signal value;
The image display device has a degeneration table indicating the correspondence between the floating maximum signal value and the control value of the luminance modulation element, and the luminance modulation corresponding to the floating maximum signal value output in the second step A third step of reading the control value of the element from the degeneration table and outputting it as a luminance modulation control value;
And a fourth step of correcting the signal value of each of the plurality of color components in correspondence with the luminance modulation control value and outputting as a color modulation control value.

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