JP2009212756A - Image processor, image display device, and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor capable of improving image quality even if "flare" caused by a lens occurs, and to provide an image display device and an image processing method. <P>SOLUTION: The image processor corrects an image signal for determining the amount of modulation in the passing light of the lens. The image processor includes: a flare model calculation section for calculating a flare model corresponding to a position on the lens through which the passing light passes; and an image signal correction section for correcting the image signal based on the flare model obtained by the flare model calculation section. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image processing device, an image display device, and an image processing method.

  When an image is projected using a projection lens (lens in a broad sense) as in an image projection apparatus, image blur called “flare” may occur around pixels on the screen on which the projected image is projected. "Flare" is one of the factors that degrade the image resolution and color reproducibility and degrade the image quality. For such “flares”, for example, as disclosed in Patent Document 1, flare measurement is performed by taking into account the influence of adjacent pixels by using a test pattern that lights adjacent pixels in a certain direction. A method is disclosed.

  Further, for example, Patent Document 2 discloses a technique in which the effect of “flare” is reduced and color reproduction is performed as intended. In this case, display characteristics are obtained from the image data of the display image and the spatial distribution of the display color of the display image, and the image data is corrected based on the display characteristics.

JP 2007-198849 A JP 2005-189542 A

  However, since the “flare” is caused by the projection lens system (projection optical system), even if the “flare” is measured as disclosed in Patent Document 1 and Patent Document 2, This is not true, and there is a problem that errors in measurement results increase.

  The present invention has been made in view of the technical problems as described above, and one of the purposes thereof is an image processing apparatus capable of improving the image quality even when a “flare” caused by a lens occurs, An object is to provide an image display device and an image processing method.

  In order to solve the above problems, the present invention is an image processing apparatus that corrects an image signal that determines a modulation amount of light passing through a lens, and calculates a flare model corresponding to a position on the lens through which the passing light passes. And an image signal correction unit that corrects the image signal based on the flare model obtained by the flare model calculation unit.

  According to the present invention, when an image is displayed using a lens, a flare model corresponding to the position on the lens through which the passing light passes is calculated, and the modulation amount of the passing light is determined based on the flare model. Since the image signal is corrected, the image quality can be improved without measuring “flare” even when “flare” occurs due to the lens.

  Further, in the image processing device according to the present invention, the image signal correction unit outputs the image signal corresponding to the pixel by using a pixel value of a peripheral pixel of the pixel on the lens based on the flare model. It can be corrected.

  According to the present invention, since the image signal corresponding to the pixel is corrected using the pixel values of the peripheral pixels of the pixel defined by the position on the lens, the image quality corresponding to the shape of the “flare” Can be improved.

  In the image processing apparatus according to the present invention, the position on the lens may be specified using polar coordinates having a center position of the lens as an origin.

  According to the present invention, since the position on the lens is specified based on the center position of the lens, pixels having the same lens center position can be corrected in the same manner, and the image signal correction process is simplified. It becomes possible to become.

  Further, in the image processing apparatus according to the present invention, the flare model is specified using a length in the sagittal direction based on the center position of the lens and a length in the meridional direction based on the center position of the lens. May be.

  According to the present invention, since the shape of the flare model can be specified with a smaller number of parameters, the capacity of the flare model can be reduced.

  The image processing apparatus according to the present invention further includes a zoom position acquisition unit that acquires a zoom position of the lens, and the flare model calculation unit is a flare model corresponding to the zoom position acquired by the zoom position acquisition unit. Can be calculated.

  According to the present invention, it is possible to improve the image quality even when a “flare” whose shape changes according to the zoom position of the lens occurs.

  The image processing apparatus according to the present invention further includes a flare model data storage unit that stores a plurality of flare model data corresponding to the zoom amount of the lens, and the flare model calculation unit is acquired by the zoom position acquisition unit. The flare model data corresponding to the zoom amount of the lens is read based on the zoom position, and the image signal correction unit can correct the image signal based on the flare model data.

  According to the present invention, even when a “flare” whose shape changes according to the zoom position occurs, a flare model corresponding to the appearance of the “flare” can be calculated, and the image quality can be improved according to the shape of the “flare”. Can be improved.

  Further, the present invention provides an image including a light modulation element that modulates the passing light based on the image signal, a lens through which the passing light passes, and the image processing device according to any one of the above that outputs the image signal. Related to display device.

  According to the present invention, it is possible to provide an image display device capable of improving the image quality even when “flare” due to a lens occurs.

  The present invention is also an image processing method for correcting an image signal that defines a modulation amount of light passing through a lens, and a flare model calculating step for calculating a flare model corresponding to a position on the lens through which the passing light passes. , And an image signal correction step of correcting the image signal based on the flare model obtained in the flare model calculation step.

  According to the present invention, when an image is displayed using a lens, a flare model corresponding to the position on the lens through which the passing light passes is calculated, and the modulation amount of the passing light is determined based on the flare model. Since the image signal is corrected, the image quality can be improved without measuring “flare” even when “flare” occurs due to the lens.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. Also, not all of the configurations described below are essential constituent requirements of the present invention.

  Hereinafter, a projector will be described as an example of the image display device. However, the present invention is not limited to the projector and can be applied to various image display devices. Many projectors today are equipped with an optical zoom function that changes the size of a projected image without changing the distance between the projector and the screen in order to increase the degree of freedom of installation. Therefore, the following projector will be described as having a projection lens and realizing an optical zoom function using the projection lens.

  FIG. 1 shows a block diagram of a configuration example of a display system to which a projector according to an embodiment of the present invention is applied.

  The display system 2 includes a projector (image display device in a broad sense) 10 and a screen SCR. In the display system 2, an input image signal is input to the projector 10, and an image projected using a projection lens (lens) included in the projector 10 is displayed on the screen SCR. The projector 10 can adjust the zoom position of the projection lens, and can enlarge or reduce the image projected on the screen SCR.

  The projector 10 includes an image processing unit (an image processing device in a broad sense) 20, a projection control unit 50, and a projection unit 100. The image processing unit 20 corrects the image signal that determines the modulation amount of the light passing through the projection lens of the projector 10. More specifically, the image processing unit 20 creates a flare model and corrects the input image signal according to the flare model, thereby displaying an image whose image quality does not deteriorate even if “flare” occurs. Can do.

Here, the principle of the correction processing of the image processing unit 20 in the present embodiment will be briefly described. First, the arrangement of the image signal of the input image is P, the flare characteristic matrix indicating how the input pixel “blurs” in the vicinity thereof is M, the arrangement of the “leakage light” level is O, and the display image of the screen SCR Assuming that the array of pixel values is G, G is expressed by the following equation.

Here, if the number of pixels for one screen is N, equation (1) can be expressed as follows.

In the equation (2), the matrix G is represented by (g ₁ , g ₂ ,..., G _N ) in which pixel values of N pixels of the display image are arranged one-dimensionally, and the matrix P is the N of the input image. The pixel value of each pixel is expressed by (p ₁ , p ₂ ,..., P _N ) arranged in one dimension, and the matrix O is “leakage light” of each pixel when “black” is displayed for all pixels. ”Is represented in a one-dimensional array (o ₁ , o ₂ ,..., O _N ). The matrix M is represented by (m ₁₁ , m ₁₂ ,..., M _NN ) in which coefficient values indicating the degree of contribution to “flare” are two-dimensionally arranged for each of N pixels of the image. It is a flare characteristic matrix.

Accordingly, when it is desired to display an image represented by the matrix P on the screen SCR, if the equation (1) is modified, the image represented by the matrix P ′ of the following equation is input, so that in principle An image without the influence of “flare” can be displayed.

  However, assuming that the number of pixels of the projected image of the projector 10 is, for example, XGA size (1024 pixels × 768 pixels), N is about 800,000, and the matrix M is a matrix having a scale of 800,000 × 800,000. End up. However, since the influence of “flare” actually affects the peripheral pixels of the pixel, most coefficient values (element values) of the matrix M are “0”. Therefore, in Patent Document 1, one screen is divided into several areas, and a flare model is estimated based on a result measured for each area.

  However, as described above, the “flare” is caused by the projection lens of the projector 10, and even if the flare model is estimated based on the result measured for each region, the error becomes large and the image quality is sufficiently high. Cannot be improved. Therefore, in the present embodiment, the image processing unit 20 generates a flare model based on the characteristics of the projection lens included in the projection unit 100, and corrects the image signal based on the flare model.

  Such an image processing unit 20 includes an input signal processing unit 22, an image signal correction unit 24, an output signal processing unit 26, a zoom position acquisition unit 28, and a flare model calculation unit 30.

  The input signal processing unit 22 performs A / D conversion processing on the input image signal, for example, processing for converting an interlaced image signal into a progressive image signal, and the like. The flare model calculation unit 30 calculates a flare model corresponding to the position on the projection lens through which the light passing through the projection lens (lens) of the projection unit 100 passes. Such a flare model calculation unit 30 includes a flare model data storage unit 32 and a control unit 34. The flare model data storage unit 32 stores flare model data corresponding to parameters defining the flare model described later as a table, outputs the flare model data to the control unit 34, and the flare model calculation unit 30 Output as a flare model.

  The image signal correction unit 24 corrects the image signal based on the flare model obtained by the flare model calculation unit 30. More specifically, the image signal correction unit 24 uses the pixel values of the peripheral pixels of the pixel on the projection lens based on the flare model obtained by the flare model calculation unit 30 to correspond to the image signal. Correct. The output signal processing unit 26 performs raster conversion, for example, on the image signal corrected by the image signal correction unit 24. The image signal processed by the output signal processing unit 26 is input to the projection control unit 50.

  The zoom position acquisition unit 28 acquires the zoom position of the projection lens. The flare model calculation unit 30 (more specifically, the control unit 34) reads the flare model data corresponding to the zoom position of the projection lens acquired by the zoom position acquisition unit 28 from the flare model data storage unit 32 as a calculation result. Can do. The image signal correction unit 24 corrects the image signal based on the flare model data.

  The projection control unit 50 includes a light modulation element driving unit 52 and a zoom adjustment unit 54. The light modulation element driving unit 52 generates a drive signal for driving the light modulation element (light valve) included in the projection unit 100 based on the image signal after processing by the output signal processing unit 26 of the image processing unit 20, The light modulation element is driven. The zoom adjustment unit 54 performs control to adjust the zoom position of the projection lens included in the projection unit 100. Such a function of the zoom adjustment unit 54 is realized by the user of the projector 10 manually adjusting the zoom position of the projection lens or adjusting the zoom position by electrical control according to the user's instruction. . The zoom position of the projection lens adjusted by the zoom adjustment unit 54 is acquired by the zoom position acquisition unit 28.

  The projection unit 100 includes a light source 110, a light modulation element (light valve) 130, and a projection lens (lens) 170. The light source 110 generates light to be projected. The light modulation element 130 modulates the light from the light source 110 based on the drive signal from the light modulation element drive unit 52 and irradiates the projection lens 170 with the modulated light. The projection lens 170 projects light onto the screen SCR using the light modulated by the light modulation element 130. Thus, since the drive signal from the light modulation element drive unit 52 is generated based on the input image signal, the projection unit 100 can project and display an image corresponding to the image signal on the screen SCR.

  FIG. 2 shows a configuration example of the projection unit in FIG. 2, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The projection unit 100 includes a light source 110, integrator lenses 112 and 114, a polarization conversion element 116, a superimposing lens 118, an R dichroic mirror 120R, a G dichroic mirror 120G, a reflection mirror 122, an R field lens 124R, and a G field lens 124G. , R liquid crystal panel 130R (first light modulation element), G liquid crystal panel 130G (second light modulation element), B liquid crystal panel 130B (third light modulation element), relay optical system 140, cross dichroic A prism 160 and a projection lens 170 are included. In FIG. 2, the light modulation element 130 includes an R liquid crystal panel 130R, a G liquid crystal panel 130G, and a B liquid crystal panel 130B. The liquid crystal panels used as the R liquid crystal panel 130R, the G liquid crystal panel 130G, and the B liquid crystal panel 130B are transmissive liquid crystal display devices. The relay optical system 140 includes relay lenses 142, 144, and 146 and reflection mirrors 148 and 150.

  The light source 110 is composed of, for example, an ultra-high pressure mercury lamp, and emits light including at least R component light, G component light, and B component light. The integrator lens 112 has a plurality of small lenses for dividing the light from the light source 110 into a plurality of partial lights. The integrator lens 114 has a plurality of small lenses corresponding to the plurality of small lenses of the integrator lens 112. The superimposing lens 118 superimposes the partial light emitted from the plurality of small lenses of the integrator lens 112.

  The polarization conversion element 116 includes a polarization separation film and a λ / 2 plate, transmits p-polarized light, reflects s-polarized light, and converts p-polarized light to s-polarized light. The superimposing lens 118 is irradiated with the s-polarized light from the polarization conversion element 116.

  The light superimposed by the superimposing lens 118 is incident on the R dichroic mirror 120R. The R dichroic mirror 120R has a function of reflecting R component light and transmitting G component and B component light. The light transmitted through the R dichroic mirror 120R is applied to the G dichroic mirror 120G, and the light reflected by the R dichroic mirror 120R is reflected by the reflection mirror 122 and guided to the R field lens 124R.

  The dichroic mirror for G 120G has a function of reflecting G component light and transmitting B component light. The light transmitted through the G dichroic mirror 120G enters the relay optical system 140, and the light reflected by the G dichroic mirror 120G is guided to the G field lens 124G.

  In the relay optical system 140, in order to minimize the difference between the optical path length of the B component light transmitted through the G dichroic mirror 120G and the optical path length of the other R component and G component light, the relay lenses 142, 144, 146 is used to correct the difference in optical path length. The light transmitted through the relay lens 142 is guided to the relay lens 144 by the reflection mirror 148. The light transmitted through the relay lens 144 is guided to the relay lens 146 by the reflection mirror 150. The light transmitted through the relay lens 146 is applied to the B liquid crystal panel 130B.

  The light applied to the R field lens 124R is converted into parallel light and is incident on the R liquid crystal panel 130R. The R liquid crystal panel 130R functions as a light modulation element (light modulation unit), and the transmittance (passage rate, modulation rate) changes based on the R image signal. Therefore, the light (first color component light) incident on the R liquid crystal panel 130R is modulated based on the R image signal, and the modulated light is incident on the cross dichroic prism 160.

  The light applied to the G field lens 124G is converted into parallel light and is incident on the G liquid crystal panel 130G. The G liquid crystal panel 130G functions as a light modulation element (light modulation unit), and the transmittance (passage rate, modulation rate) changes based on the G image signal. Therefore, the light (second color component light) incident on the G liquid crystal panel 130G is modulated based on the G image signal, and the modulated light is incident on the cross dichroic prism 160.

  The B liquid crystal panel 130B irradiated with the light converted into parallel light by the relay lenses 142, 144, and 146 functions as a light modulation element (light modulation unit), and has a transmittance (passage rate) based on the B image signal. , Modulation rate) is changed. Therefore, the light (third color component light) incident on the B liquid crystal panel 130B is modulated based on the B image signal, and the modulated light is incident on the cross dichroic prism 160.

  The R liquid crystal panel 130R, the G liquid crystal panel 130G, and the B liquid crystal panel 130B have the same configuration. Each liquid crystal panel is a liquid crystal, which is an electro-optical material, sealed and encapsulated in a pair of transparent glass substrates. For example, a polysilicon thin film transistor is used as a switching element, and the transmittance of each color light is corresponding to the image signal of each pixel. Modulate.

  In the present embodiment, the drive signals generated by the light modulation element driving unit 52 of the projection control unit 50 are transmitted through the R liquid crystal panel 130R, the G liquid crystal panel 130G, and the B liquid crystal panel 130B, respectively. Rate).

  The cross dichroic prism 160 has a function of outputting combined light obtained by combining incident light from the R liquid crystal panel 130R, the G liquid crystal panel 130G, and the B liquid crystal panel 130B as outgoing light. The projection lens 170 is a lens that enlarges and forms an output image on the screen SCR, and has a function of enlarging or reducing the image in accordance with the zoom magnification.

  Hereinafter, in the projector 10 having the above-described configuration, the processing of the image processing unit 20 that improves the image quality even when “flare” occurs will be described in detail.

3A and 3B are explanatory diagrams of flare in the present embodiment. FIG. 3A shows the positional relationship between the projection lens 170 and the light modulation element. FIG. 3B schematically shows the flare when attention is paid to the pixels on the screen SCR.
FIG. 4 shows a schematic shape of the flare in the present embodiment.

  As shown in FIG. 3A, the center position of the light region 300 that passes through the liquid crystal panel irradiated with the light from the light source 110 is shifted from the center position OC of the projection lens 170. Therefore, as shown in FIG. 3B, when the light that has passed through the projection lens 170 is projected as a projection image IMG in the projection area 310 on the screen SCR, the light shown in FIG. The flare of the pixel P1 in the region 300 has a shape shown in FIG. 3B on the screen SCR. In other words, the shape of the flare F1 is as shown in FIG. 4 due to the influence of the projection optical system such as the projection lens 170 on the shape of the pixel P1 of the liquid crystal panel in which light from the light source 110 is modulated.

  5A and 5B are explanatory diagrams of image quality deterioration caused by flare. FIG. 5A schematically illustrates an arrangement example of pixels of the liquid crystal panel. FIG. 5B illustrates a state in which an image blurs due to flare.

  As shown in FIG. 5A, since the pixels of the liquid crystal panel as the light modulation elements are two-dimensionally arranged in the horizontal direction and the vertical direction, ideally, the light of each pixel is also displayed on the screen SCR. However, it is desirable to display as an image without interfering with the light of the adjacent pixels. However, since flare occurs in each pixel as shown in FIG. 4, the light on the adjacent pixels interferes with each other as shown in FIG. 5B, and the image on the screen SCR blurs, resulting in deterioration of image quality.

  Therefore, in this embodiment, image quality deterioration is suppressed by correcting the input image signal so that a desired pixel value can be obtained for each pixel even if flare occurs. That is, in the present embodiment, correction is performed in consideration of the influence of surrounding pixels for each pixel position. According to this embodiment, when an image is displayed using a lens, a flare model corresponding to the position on the lens through which the passing light passes is calculated, and the modulation amount of the passing light is calculated based on the flare model. Since the predetermined image signal is corrected, even when “flare” occurs due to the lens, the image quality can be improved without measuring “flare”. Furthermore, according to this embodiment, the image signal corresponding to the pixel is corrected using the pixel value of the peripheral pixel of the pixel defined by the position on the lens, so that the “flare” shape is obtained. The image quality can be improved accordingly.

  Here, since the influence of flare is caused by the position of the projection lens, it is desirable to use a pixel position specified based on the center position of the projection lens as follows.

  6A and 6B are schematic diagrams of the display system 2 in the present embodiment. FIG. 6A shows the display system 2 as viewed from the side. FIG. 6B illustrates the display system 2 as viewed from the front with respect to the screen SCR. 6A and 6B, the same portions as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  As shown in FIG. 6A, generally, the projector 10 projects an image so that the projected image spreads upward with respect to the center position OC of the projection lens 170 of the projector 10. By doing so, the projector 10 can display a large image on the screen SCR even if the position from the screen SCR is close.

  Accordingly, as shown in FIG. 6B, the center position OCC of the projected image on the screen SCR and the pixel position OCP projected from the center position OC of the projection lens 170 of the projector 10 are different. Therefore, in the present embodiment, correction processing corresponding to the pixel position is performed on the pixels in the lens coordinate system defined on the projection lens 170. Therefore, in the present embodiment, the following terms are used to calculate the flare model for the pixels in the lens coordinate system.

  In FIG. 7, the explanatory view of the term for defining the flare model in this embodiment is shown. FIG. 7 shows concentric circles centered on the center position OC of the projection lens 170.

  The flare model in the present embodiment is expressed using the following three elements with the center position OC of the projection lens 170 as a reference. The first element is an image height h that is a distance from the center position OC of the projection lens 170. The second element is a sagittal direction S that is a concentric direction around the center position OC of the projection lens 170. The third element is a meridional direction M that is a radiation direction with reference to the center position OC of the projection lens 170. More specifically, when the pixel is located on a concentric circle centered on the center position OC of the projection lens 170, the image height h is the radius of the concentric circle passing through the pixel, and the sagittal direction S is A tangential direction of concentric circles, and a meridional direction M is a direction from the pixel position toward the center position OC or the opposite direction. By doing this, the shape of the flare model can be specified (calculated) with a smaller number of parameters, so that the capacity of flare model data defining the flare model can be reduced.

  The flare model in the present embodiment is specified by the following flare model parameters (flare model data) using the above three elements.

  FIG. 8 is an explanatory diagram of the flare model in the present embodiment.

  FIG. 8 shows a flare model that represents the flare of the i-th pixel (i, j) in the horizontal direction and the j-th pixel in the vertical direction on the projection lens 170. Here, the angle formed by the first horizontal direction of the projection image from the center position OC of the projection lens 170 and the straight line connecting the pixel (i, j) and the center position OC is θ, and the pixel (i, j) If the distance (image height) between the center position OC and the center position OC is h, the position on the projection lens 170 (the position where the light passing through the pixel passes) is a pixel using polar coordinates centered on the center position OC of the projection lens 170. (I, j) can be specified. In this way, since the position on the projection lens is specified based on the center position of the projection lens, pixels having the same lens center position can be similarly corrected, and image signal correction processing can be performed. It can be simplified.

  In this embodiment, the flare model at the pixel (i, j) on the projection lens specified in this way is represented by parameters Mo (θ, h), Mi (θ, h), and S (θ, h). To express.

  The parameter Mo (θ, h) represents the length of the flare outside the meridional direction at the angle θ and the image height h. That is, the parameter Mo (θ, h) represents the length of the flare in the radiation direction toward the outside of the concentric circle with the center position OC of the projection lens 170 as the center, based on the position of the pixel (i, j).

  The parameter Mi (θ, h) represents the length of the flare inside the meridional direction at the angle θ and the image height h. That is, the parameter Mi (θ, h) represents the length of the flare in the radiation direction toward the inside of the concentric circle with the center position OC of the projection lens 170 as the center, with the position of the pixel (i, j) as a reference.

  The parameter S (θ, h) represents the width of the flare in the sagittal direction at the angle θ and the image height h. That is, the parameter S (θ, h) represents the width of the flare in the concentric direction with the position of the pixel (i, j) as a reference.

  That is, in the present embodiment, the flare model is specified using the length in the sagittal direction with respect to the center position OC of the projection lens and the length in the meridional direction with respect to the center position of the projection lens. In the present embodiment, the flare model data stored in the flare model data storage unit 32 in FIG. 1 is the parameters Mo (θ, h), Mi (θ, h), and S (θ, h).

  By the way, the flare model data for specifying such a “flare” shape generally does not depend on the angle θ due to the characteristics of the projection lens 170. However, the appearance of “flare” varies depending on the zoom position of the projection lens 170. Therefore, it is desirable that the flare model data storage unit 32 stores flare model data corresponding to the zoom position (zoom amount) of the projection lens 170.

  9A and 9B are explanatory diagrams of the zoom position of the projection lens 170 of the projector 10 according to the present embodiment. FIG. 9A illustrates the zoom position of the projection lens 170 when the zoom magnification is small, and FIG. 9B illustrates the zoom position of the projection lens 170 when the zoom magnification is large.

  As described above, when the zoom position of the projection lens 170 of the projector 10 is changed in a state where the distance to the screen SCR is constant, the appearance of “flare” differs in each pixel of the projection image.

  Therefore, in the present embodiment, the flare model data storage unit 32 can store a plurality of flare model data corresponding to the zoom amount of the projection lens. Then, the flare model calculation unit 30 reads flare model data corresponding to the zoom amount of the projection lens based on the zoom position of the projection lens acquired by the zoom position acquisition unit 28, and the image signal is based on the flare model data. It is desirable to be corrected. Thus, even when the zoom position of the projection lens 170 changes, the image signal can be corrected accurately, and the image quality can be improved regardless of the zoom amount.

  Next, details of a processing example of the image processing unit 20 in the present embodiment will be described.

  FIG. 10 shows a block diagram of a hardware configuration example of the image processing unit 20 in the present embodiment.

  The image processing unit 20 includes a CPU 400, an I / F circuit 410, a read only memory (ROM) 420, a random access memory (RAM) 430, and a bus 440. The CPU 400, the I / F circuit 410, the ROM 420, and the RAM 430 are electrically connected.

  For example, the ROM 420 stores a program that realizes the function of the image processing unit 20. The CPU 400 reads the program stored in the ROM 420 and executes processing corresponding to the program, whereby the functions of the image processing unit 20 described above can be realized by software processing. The RAM 430 realizes the function of the flare model data storage unit 32 and is used as a work area for processing by the CPU 400 or as a buffer area for the I / F circuit 410 or the ROM 420. The I / F circuit 410 performs input interface processing of an image signal from an image signal generation device (not shown) and reception processing of a zoom amount from the zoom adjustment unit 54.

  FIG. 11 shows a flowchart of a processing example of the image processing unit 20 in the present embodiment.

  A program for realizing the processing shown in FIG. 11 is stored in the ROM 420 of FIG. 10 in advance, and the CPU 400 reads out the program stored in the ROM 420 and executes the processing corresponding to the program. The processing shown can be realized by software processing.

  First, the image processing unit 20 acquires the zoom position, which is the adjustment result of the zoom adjustment unit 54, by the function of the zoom position acquisition unit 28 (step S10). Then, the image processing unit 20 specifies the positions of the liquid crystal panels 130R, 130G, and 130B as the light modulation elements 130 corresponding to the center position OC of the projection lens 170, and calculates the center position of the projection lens in the panel coordinate system ( Step S12).

  Thereafter, the image processing unit 20 buffers, for example, an image signal for one screen (step S14) and stores it in a frame buffer (not shown) (RAM 430 in FIG. 10).

  Thereafter, the image processing unit 20 performs processing for each color component constituting one pixel.

  That is, the image processing unit 20 acquires flare model data at the pixel position for each color component of the pixel (i, j) (step S14). More specifically, when the center position of the projection lens in the panel coordinate system is calculated in step S12, the image height h and the angle θ at the pixel (i, j) can be obtained, so that the flare stored in the flare model data storage unit 32 is obtained. Each value of the flare parameters Mo (θ, h), Mi (θ, h), and S (θ, h) is acquired from the model data.

  12A and 12B are explanatory diagrams of flare model data stored in the flare model data storage unit 32. FIG.

  As shown in FIG. 12A, the flare model data storage unit 32 corresponds to, for example, the image height h, and the values of flare parameters Mo (h), Mi (h), S (h) as flare model data. Remember. As a result, the flare parameters Mo (h), Mi (h), and S (h) are the same regardless of the angle θ due to the characteristics of the projection lens 170. Therefore, the data capacity to be stored by the flare model data storage unit 32 is reduced. Can be reduced.

  Further, the flare model data storage unit 32 stores flare model data corresponding to the zoom position acquired by the zoom position acquisition unit 28, as shown in FIG. This is because the appearance of the “flare” varies depending on the zoom position of the projection lens 170, and the flare model data is stored for each zoom position, so that the image quality can be improved more accurately.

  As described above, the flare model data storage unit 32 and the control unit 34 realize the function of the flare model calculation unit 30, store flare model data in advance as a flare model calculation step, and select from the flare model data. The flare model data at each pixel position is output according to the zoom position from the zoom position acquisition unit 28. Thus, when the flare model data corresponding to the zoom position is acquired in step S16 of FIG. 11, the image processing unit 20 calculates the coverage ratio of the peripheral pixels by the “flare” of the pixel (step S18). Then, as the image signal correction step, the image processing unit 20 corrects the image signal of the pixel using the coverage obtained in step S18 in the image signal correction unit 24 (step S20).

  FIG. 13A and FIG. 13B are explanatory diagrams of image signal correction processing of the pixel by the image processing unit 20 in the present embodiment. FIG. 13A schematically shows the pixel (i, j) in the panel coordinate system, and FIG. 13B schematically shows the coverage of the peripheral pixels of the pixel.

When the flare model data is acquired in step S16 of FIG. 11, the flare shape of the pixel (i, j) is determined. For example, when attention is paid to the pixel (i, j) in FIG. 13A, the coverage of a flare of, for example, four pixels including the pixel (i, j) among the peripheral pixels of the pixel is calculated. The flare area is S, the flare coverage of pixel a (pixel value a) is Sa, the flare coverage of pixel b (pixel value b) is Sb, and the flare coverage of pixel c (pixel value c) is Sc. Assuming that the flare coverage of the pixel d (pixel value d) is Sd, the image signal correction unit 24 calculates the pixel value (image signal) sig of the pixel (i, j) (pixel d) as follows: The corrected pixel value (image signal) sigd after correction is output.

  Thereafter, in FIG. 11, when the image signal of the next color component is corrected (step S22: Y), the image processing unit 20 returns to step S16 and continues the processing. In step S22, when the image signal of the next color component is not corrected (step S22: N), when the image signal is corrected for the next pixel (step S24: Y), the pixel position is updated ( In step S26), the process returns to step S16 to continue the process. When the image signal is not corrected for the next pixel (step S24: N), the series of processes is terminated (END).

FIG. 14 shows a flowchart of a detailed processing example of step S18 of FIG.
15 and 16 are explanatory diagrams of step S30 in FIG.
FIG. 17 is an explanatory diagram of steps S34 and S36 in FIG.
18A and 18B are explanatory diagrams of steps S36 and S38 in FIG.

  In calculating the coverage ratio of the peripheral pixels of the pixel, the image processing unit 20 first calculates a pixel (based on the angle θ obtained in step S12 and subsequent steps in FIG. 11 and the flare model data acquired in step S16. The coordinates of four points on the outer periphery of the flare of i, j) are calculated (step S30). In other words, as shown in FIG. 15, when a square region having a side corresponding to the pixel pitch is defined as a pixel region, the flare parameter (flare model data) Mo () is based on the center position of the pixel (i, j). The coordinates of the four outer peripheral points are obtained using θ, h), Mi (θ, h), and S (θ, h). Since the square area is used for calculating the area as described later, each coordinate position is determined with a resolution of 10 × 10, for example, as shown in FIG.

  Next, the image processing unit 20 performs a process of connecting the outer circumferences of the four points obtained in step S30 (step S32). In step S32, it is not necessary to connect with a straight line, and it may be connected with a given line such as a spline curve. Subsequently, the image processing unit 20 calculates an internal area surrounded by the connection in step S32 (step S34). In step S34, for example, the number of areas filled with the connection can be calculated as the area.

  Then, the image processing unit 20 calculates the area of the area around the pixel among the areas connected in step S32 (step S36), and calculates the coverage as shown in the above equation (step S38). For example, as shown in FIG. 18A, the area of the upper left peripheral pixel (pixel value sig11) of the pixel is “38”, the area of the upper right peripheral pixel (pixel value sig12) is “23”, Since the area of the peripheral pixel (pixel value sig21) is “27” and the area of the pixel (pixel value sig) is “96”, the area inside the connection is “184” (= 38 + 23 + 27 + 96). The pixel coverage is as shown in FIG.

Therefore, in this case, the pixel value (image signal) sig of the pixel is obtained by weighting calculation as in the following equation.

  As described above, in the present embodiment, a flare model is calculated for each pixel defined in the lens coordinate system of the projection lens, and pixels around the pixel defined in the panel coordinate system are calculated based on the flare model. The pixel value of the pixel is corrected using the value (image signal). By doing so, the image quality can be improved even if “flare” due to the projection lens occurs.

  The image processing apparatus, the image display apparatus, and the image processing method according to the present invention have been described based on the above embodiments. However, the present invention is not limited to the above embodiments, and does not depart from the spirit of the present invention. Can be implemented in various modes, and for example, the following modifications are possible.

  (1) In the above embodiment, the projector has been described as an example of the image display device, but the present invention is not limited to this. Needless to say, the present invention can be applied to an image display device that displays an image using a lens.

  (2) In the above embodiment, one pixel is described as being composed of three color component sub-pixels, but the present invention is not limited to this. The number of color components constituting one pixel may be 2, or 4 or more.

  (3) In the above embodiment, the light valve is used as the light modulation element. However, the present invention is not limited to this. As the light modulation unit, for example, DLP (Digital Light Processing) (registered trademark), LCOS (Liquid Crystal On Silicon), or the like may be employed.

  (4) In the above embodiment, a light valve using a so-called three-plate transmissive liquid crystal panel as an example of the light modulation element has been described. However, a light valve using a transmissive liquid crystal panel of four or more plates is used. It may be adopted.

  (5) In the above embodiment, the present invention has been described as an image processing apparatus, an image display apparatus, and an image processing method, but the present invention is not limited to this. For example, it may be a program in which a processing procedure of an image processing method for realizing the present invention is described, or a recording medium on which the program is recorded.

1 is a block diagram of a configuration example of a display system to which a projector according to an embodiment of the present invention is applied. The figure which shows the structural example of the projection part of FIG. 3 (A) and 3 (B) are explanatory diagrams of flare in the present embodiment. The figure which shows the typical shape of the flare in this embodiment. 5A and 5B are explanatory diagrams of image quality deterioration caused by flare. 6A and 6B are schematic views of the display system in the present embodiment. Explanatory drawing of the term for defining the flare model in this embodiment. Explanatory drawing of the flare model in this embodiment. 9A and 9B are explanatory diagrams of the zoom position of the projection lens of the projector according to the present embodiment. The block diagram of the hardware structural example of the image process part in this embodiment. The flowchart of the example of a process of the image process part in this embodiment. 12A and 12B are explanatory diagrams of flare model data stored in the flare model data storage unit. FIG. 13A and FIG. 13B are explanatory diagrams of image signal correction processing of the pixel by the image processing unit in the present embodiment. FIG. 12 is a flowchart of a detailed processing example of step S18 in FIG. 11. Explanatory drawing of step S30 of FIG. Explanatory drawing of step S30 of FIG. Explanatory drawing of step S34 of FIG. 14, step S36. 18A and 18B are explanatory diagrams of step S36 and step S38 in FIG.

Explanation of symbols

2 ... Display system, 10 ... Projector, 20 ... Image processing unit,
22 ... an input signal processing unit, 24 ... an image signal correction unit, 26 ... an output signal processing unit,
28 ... zoom position acquisition unit, 30 ... flare model calculation unit,
32 ... Flare model data storage unit, 34 ... Control unit, 50 ... Projection control unit,
52 ... Light modulation element drive unit, 54 ... Zoom adjustment unit, 100 ... Projection unit, 110 ... Light source,
112, 114 ... integrator lens, 116 ... polarization conversion element,
118 ... Superimposing lens, 120R ... R dichroic mirror,
120G ... Dichroic mirror for G, 122,148,150 ... Reflective mirror,
124R ... R field lens, 124G ... G field lens,
130 ... Light modulation element 130R ... R liquid crystal panel, 130G ... G liquid crystal panel,
130B ... Liquid crystal panel for B, 140 ... Relay optical system,
142, 144, 146 ... relay lens, 160 ... cross dichroic prism,
170 ... Projection lens, SCR ... Screen

Claims (8)

An image processing apparatus that corrects an image signal that determines a modulation amount of light passing through a lens,
A flare model calculation unit that calculates a flare model corresponding to a position on the lens through which the passing light passes;
An image processing apparatus comprising: an image signal correcting unit that corrects the image signal based on the flare model obtained by the flare model calculating unit. In claim 1,
The image signal correction unit
An image processing apparatus that corrects the image signal corresponding to the pixel by using pixel values of peripheral pixels of the pixel on the lens based on the flare model. In claim 1 or 2,
The position on the lens is
An image processing apparatus characterized by being specified using polar coordinates having a center position of the lens as an origin. In any one of Claims 1 thru | or 3,
The flare model is
An image processing apparatus characterized by being specified using a length in a sagittal direction with respect to a center position of the lens and a length in a meridional direction with respect to the center position of the lens. In any one of Claims 1 thru | or 4,
A zoom position acquisition unit for acquiring a zoom position of the lens;
The flare model calculation unit
An image processing apparatus that calculates a flare model corresponding to the zoom position acquired by the zoom position acquisition unit. In claim 5,
A flare model data storage unit that stores a plurality of flare model data corresponding to the zoom amount of the lens;
The flare model calculation unit
Based on the zoom position acquired by the zoom position acquisition unit, reads flare model data corresponding to the zoom amount of the lens,
The image signal correction unit
An image processing apparatus, wherein the image signal is corrected based on the flare model data. A light modulation element that modulates the passing light based on the image signal;
A lens through which the passing light passes;
An image display apparatus comprising: the image processing apparatus according to claim 1 that outputs the image signal. An image processing method for correcting an image signal that determines a modulation amount of light passing through a lens,
A flare model calculating step of calculating a flare model corresponding to a position on the lens through which the passing light passes;
An image signal correcting step of correcting the image signal based on the flare model obtained in the flare model calculating step.