JP2008292906A - Projection system, projector, illumination controller and illuminator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection system by which a viewer can view a vivid color of image signals which can not be reproduced by a light source of a projector even in a projector using the conventional light source. <P>SOLUTION: The projection system is equipped with the projector to project the image signal, a screen to selectively reflect RGB light from RGB light sources of the projector, and an illuminator having R'G'B' light whose frequency is different from the RGB light sources as a light source, and is equipped with a signal processing means to detect a color signal which can not be reproduced by the light source of the projector from the image signal, and control the illuminator in a complementary color direction to the color signal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a projection system that projects an image signal onto a screen, a projector, an illumination control device, and an illumination device.

  Large-screen display devices such as liquid crystal and plasma have become popular in place of cathode ray tubes. In particular, if a projection type projection system is used, a large screen display can be realized very easily. However, the conventional projection method has a drawback that contrast cannot be obtained in a bright room, and improvement is demanded.

  As one solution, there is a projection system disclosed in Patent Document 1. The projection system includes a projector that projects an image signal, a screen that selectively reflects the RGB light source of the projector, and an illumination device that uses R′G′B ′ having a frequency different from that of the RGB light source as a light source. ing. That is, a light source having a frequency different from that of the projector light source is used for illumination, the screen selectively reflects only the projection light of the projector, and the illumination of the light source absorbs.

  Patent Document 2 discloses a light color variable illumination that matches chromaticity and luminance extracted from an image signal. It is intended to control the illumination in real time according to the image signal. However, it does not mention what color the lighting is controlled to be concrete.

JP 2003-344951 A Japanese Patent Laid-Open No. 2-158094

  Here, the color reproduction range in the projection system will be described.

  FIG. 9 shows a chromaticity diagram. One hue is expressed by the intersection of the xy2 axes, and the brightness of the color is expressed by another axis (not shown). In the figure, the vertex of the triangle indicates the RGB of the light source, and the color inside the triangle can be reproduced. The point C indicates a white point, and the color becomes more saturated as the point moves radially away from the point C. The two triangles in the figure correspond to the color reproduction ranges on the image pickup side and the display side, respectively, and the triangle on the image pickup side is larger, and it is general that all the captured colors cannot be displayed on the display side.

  In recent years, there has been a movement to expand the color reproduction range on the display side, but the display side (projector) can hardly catch up compared to the imaging side (image signal output source such as a video camera) using an expensive device. is the current situation. For example, even if an attempt is made to display the color of the point A in the figure transmitted from the imaging side, the color of the point A ′ is obtained on the display side. As shown in FIG. 10, even if there is an input (horizontal axis) with high saturation above a predetermined level, it is not possible to display more than the limit value.

  The techniques of Patent Documents 1 and 2 described above do not solve the problems described above.

  Therefore, the present invention provides a projection system, a projector, a lighting control device, and a lighting device that enable viewers to experience vivid colors that cannot be reproduced by a light source of a projector among image signals, even in a projector that uses a conventional light source. It is an object.

As means for solving the above problems, the present invention provides:
A projector that projects image signals;
A screen that selectively reflects the RGB light source of the projector;
In a projection system comprising an illumination device that uses R′G′B ′ having a frequency different from that of the RGB light source,
The image processing apparatus includes a signal processing unit that detects a color signal that cannot be reproduced by a light source of a projector from the image signal and controls the illumination device in a complementary color direction with respect to the color signal.

  When the projection system, projector, illumination control device, and illumination device according to the present invention are used, the viewer can experience vivid colors that cannot be reproduced by the light source of the projector among the image signals, even in the projector using the conventional light source.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

  The projection system shown in FIG. 1 includes a projector 1 that projects an image signal 4 input from an output source such as a video camera, and a screen 2 that selectively reflects the RGB light source of the projector 1. Furthermore, it has the illuminating device 3 which uses R'G'B 'with a different frequency from the RGB light source.

  The projector 1 includes a light source that emits three colors of RGB, and a light valve (for example, a liquid crystal panel) that modulates the intensity of the luminous flux emitted from the light source for each of the three colors of RGB according to the image signal 4. A projection lens for superimposing the RGB three-color light intensity-modulated by the light valve on the screen 2 to form an image is provided. In order to make the effect of the present invention more remarkable, it is desirable that the bandwidth of each light source is as narrow as possible, for example, an LED or a laser light source is used.

  The screen 2 selectively reflects the RGB light source of the projector 1, that is, has a high reflectivity only in the vicinity of the RGB wavelength, and has a characteristic of absorbing light of other wavelengths. Specifically, three special layers of an R reflection layer, a G reflection layer, and a B reflection layer are laminated on a black base material that absorbs light, and the wavelength reflected by each layer depends on the wavelength of the projector light source. It almost coincides with the R, G and B wavelengths. Since each layer has the property of transmitting all other wavelengths, the entire screen reflects only three wavelengths of RGB, which is the light source of the projector, and other outside light reaches the base material. Absorbed and not reflected.

  The lighting device 3 is configured so that the lighting color can be changed. For example, the lighting device 3 includes a large number of LEDs (N of each color) that light up each RGB color, and the number of lighting LEDs of each color according to a lighting control signal described later. Configured to increase or decrease. Depending on the ratio of the number of lighting of each color, even in the same white, a reddish white and a bluish white can be generated. In order to make the effect of the present invention more prominent, the light source of each LED is made to have a wavelength different from that of the light source of the projector 1, and is hereinafter expressed as R'G'B '.

  The image signal 4 input to the projector 1 is converted into an RGB three-color optical signal, projected onto the screen 2, and then reflected and recognized by the viewer's eyes. On the other hand, the R′G′B ′ three-color light emitted from the illumination device 3 should also be reflected by the screen 2 and enter the viewer's eyes, but as described above, the screen 2 is in the vicinity of the RGB wavelength. Only the reflectance is high, and light of other wavelengths is transmitted. Therefore, the amount of R′G′B ′ that reaches the viewer's eyes is negligible.

  The relationship between the wavelengths of RGB and R′G′B ′ is, for example, as shown in FIG. The human eye does not have a steep selection characteristic with respect to the wavelength of light, that is, three colors of light are combined and appear as one color. Therefore, even when R′G′B ′ having a wavelength different from the RGB of the projector 1 is used as shown in FIG. 2, the color of the illumination light of the illumination device 3 can be matched with the white color on the screen 2. In the chromaticity diagram, the triangles have different vertices as shown in FIG. 3, but the white point (point C in the figure) can be matched by adjusting the balance of R'G'B '.

  Returning to FIG. 1, since the illumination light R′G′B ′ is not reflected from the screen 2, the contrast of the projected image does not decrease even when the illumination device 3 is turned on. In addition, direct light from the lighting device 3 or reflected light from a wall of a room (not shown) or the like still enters the viewer's eyes, but the viewer's line of sight may be directed toward the screen 2. Light is recognized as a peripheral color outside the screen frame.

  If the periphery of the screen 2 is a white wall and the projection of the projector 1 is turned off, the periphery is the same white color as the illumination light and the screen 2 looks black because it does not reflect the illumination light. By using such a special screen 2, even if the lighting system 3 is turned on and the room is brightened, it is possible to enjoy a comfortable appreciation with little reduction in the contrast of the screen even if the lighting device 3 is turned on.

  However, the bright colors that cannot be reproduced by the light source of the projector 1 included in the image signal 4 are not configured so that the viewer can experience them even with the above configuration.

  Therefore, the projector 1 according to this embodiment includes a signal processing unit that is a feature of the present invention. As shown in FIG. 4, the signal processing unit includes a high saturation signal detection unit 44 that detects a color signal that cannot be reproduced by the light source of the projector 1 from the image signal 4. Further, a white point in a complementary color direction is calculated with respect to the detected color signal, and an illumination control signal generation unit that generates a signal for controlling the illumination device 3 so that the illumination device 3 has illumination that matches the white point. 45.

  Specifically, how the image signal 4 input to the projector 1 is processed by the signal processing means will be described with reference to FIGS. 4 and 5. Incidentally, the image signal 4 shown in the flowchart of FIG. 5 is a signal for one screen.

  The image signal 4 is first converted into an RGB signal by the input signal processing unit 41 (S1). This is because, generally, a captured image signal is encoded and transmitted after being converted into a luminance and color difference format such as YUV instead of the RGB format. The RGB signals are subjected to signal correction for display in accordance with the characteristics of the projector 1 such as gamma correction in the display signal processing unit 42, supplied to the screen 2 via the driver 43 and projected.

  On the other hand, the RGB signal is also supplied to the high saturation signal detection unit 44, where a high saturation signal that cannot be reproduced by the light source of the projector 1 included in the image signal 4 is detected (S2). In the chromaticity diagram shown in FIG. 9, the solid triangle region is the color range of the image signal 4 captured (transmitted), and the dotted triangle region corresponds to the display range of the projector 1. The high saturation signal detection unit 44 extracts a signal outside the triangular area indicated by the dotted line in the image signal 4. At this time, since the image signal 4 cannot be determined if it is an RGB signal, calculation is performed by plotting the image signal 4 on a chromaticity diagram using the conversion formula shown in <Equation 1>. Incidentally, the color signal range that can be reproduced by the light source of the projector 1, that is, information indicating the color reproduction range of the projector 1 is input to the high saturation signal detection unit 44 in advance, and the information and the image signal 4 are compared and reproduced. A high saturation signal that cannot be detected is detected.

  As described above, the color signal area to be displayed more vividly is narrowed down from the color signals that cannot be displayed by the light source of the projector 1 that is mathematically extracted in S2 (S3, S4). In S3, a color signal having a signal intensity greater than a predetermined value is extracted, and in S4, it is determined whether or not the area has a predetermined area or more on the screen. A region having a small signal intensity even if the signal intensity is large or a region having a small signal intensity even if the area is large is excluded, and the process jumps to S7 to set the illumination control signal 5 of the illumination device 3 to 0 (C 'point = C point remains). To do.

  On the other hand, the information of the color signal extracted satisfying the condition is passed to the illumination control signal generation unit 45. The illumination control signal generation unit 45 generates the illumination control signal 5 so that the color of the illumination light changes in the complementary color direction with respect to the given color signal.

  This will be described with reference to the chromaticity diagram of FIG. Assuming that the detected color signal that cannot be displayed is point A, a point C ′ opposite to point A is obtained on a straight line connecting point A to white point C, and the color of the illumination light becomes point C ′. The illumination control signal 5 like this is generated. Specifically, in S5, an average value of each of the extracted color signals xy or a weighted average with a signal intensity weight is performed. In S6, this average value is converted into a symmetrical (complementary color) position with respect to the original white point C point, and is multiplied by k (k <1) to obtain the C 'point. In the drawing, when the length of AC is 1, the length of CC ′ is k.

  As a result, the illumination light of the illumination device 3 moves from the point C to the point C ′ in conjunction with the image signal 4. Originally, the color of the point A included in the image signal 4 cannot be reproduced by the light source of the projector 1 and is displayed as the point A ′, so that the saturation is low and the vividness is insufficient. However, at the same time, since the illumination light of the illumination device 3 becomes the point C ′ in the complementary color direction, the user can experience a vivid color closer to the point A direction.

  This is due to an illusion, and an example is shown in FIG. Both are pictures of yellow lemons, while the background on the left side is white, while the right side has a yellow complementary blue background. At this time, the yellow lemon on the right appears more vivid. In the case of illumination, even if the color is changed too much, there is a sense of incongruity. Therefore, it is desirable to control at a white level where the color temperature is different, such as a difference between an incandescent bulb and a fluorescent lamp. That is, the value of k set in advance is set to a small value (for example, 0.1) so that it can be kept in a white range even if the point C moves.

  By controlling the illumination light at the C ′ point obtained above, the viewer can experience a vivid color that cannot be reproduced by the light source of the projector 1.

<Second Embodiment>
Next, a second embodiment according to the present invention will be described with reference to the drawings.

  The aim of the present embodiment is to improve the point that the combination of the projector 1 and the illumination device 3 is a dedicated pair in the first embodiment and the degree of freedom is low. For example, according to the present embodiment, the illumination device 3 can be replaced with another projector having a different light source or color reproduction range without changing the illumination device 3.

  FIG. 7 is a configuration diagram showing the projection system according to the present embodiment. A description of portions common to FIG. 1 is omitted. A lighting control device 6 is added to FIG.

  As shown in FIG. 8, the illumination control device 6 includes an input signal processing unit that converts the image signal 4 (YUV) into RGB, and a light source color setting unit that sets the color of the light source of the projector 1. . Further, a high saturation signal detection unit for detecting a color signal that cannot be reproduced by the light source of the projector 1 from the image signal 4 is provided. An illumination control signal generation unit that calculates a white point in a complementary color direction with respect to the detected color signal and generates a signal for controlling the illumination device 3 so that the illumination device 3 has illumination that matches the white point. It has. That is, in FIG. 4, a portion for generating the illumination control signal 5 is extracted.

  What is characteristic is that a light source color setting unit to which projector information is input is added. The projector information is information indicating the color reproduction range of the projector 1 and corresponds to the RGB position (its xy value) of the light source being used. In the first embodiment, since the projector was built in the projector, the RGB position of the light source was fixed. In order to make this variable according to the projector 1 to be used, means for inputting by key input or the like may be provided, or a setting value for each model of the projector 1 is held in a memory (not shown) and selected. May be. Even if the projector 1 is changed by inputting the color reproduction range for each projector model, the effect of the present invention can be obtained. Information indicating the color reproduction range of the projector 1 is indicated by reference numeral 7 in FIG.

  A form in which the illumination control device 6 is provided inside the illumination device 3 is also possible. Also in this case, if the color reproduction range for each projector model is input to the high saturation signal detection unit, the projector 1 can be changed.

It is a block diagram of the projection system of 1st Embodiment. It is a figure which shows the relationship between the light source of a projector, and the light source of an illuminating device. It is a chromaticity diagram expressing the same white point in different RGB. It is a block diagram of the signal processing means with which the projector was equipped. It is a production | generation flowchart of the illumination control signal of 1st Embodiment. It is explanatory drawing of the effect of a complementary color. It is a block diagram of the projection system of 2nd Embodiment. It is a block diagram of an illumination control device. It is a chromaticity diagram for demonstrating the illumination control signal to produce | generate. It is a graph which shows saturation of an input color signal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projector 2 Screen 3 Illumination device 4 Image signal 5 Illumination control signal 6 Illumination control device 7 Information 41 indicating color reproduction range of projector 41 Input signal processing unit 42 Display signal processing unit 43 Driver 44 High chroma signal detection unit 45 Illumination control signal generation unit

Claims (4)

A projector that projects image signals;
A screen that selectively reflects the RGB light source of the projector;
In a projection system comprising an illumination device that uses R′G′B ′ having a frequency different from that of the RGB light source,
A projection system comprising: signal processing means for detecting a color signal that cannot be reproduced by a light source of a projector from the image signal and controlling the illumination device in a complementary color direction with respect to the color signal. A projector comprising the signal processing means of the projection system according to claim 1,
The signal processing means of the projector includes a high saturation signal detection unit that detects a color signal that cannot be reproduced by a light source of the projector from an image signal,
A lighting control signal generating unit that calculates a white point in a complementary color direction with respect to the detected color signal and generates a signal for controlling the lighting device so that the lighting device has an illumination that matches the white point; A projector, characterized by An illumination control device used as signal processing means of the projection system according to claim 1,
The illumination control device includes an input signal processing unit for image signals,
A light source color setting unit for setting the color of the light source of the projector;
A high saturation signal detection unit for detecting a color signal that cannot be reproduced by a light source of the projector from the image signal;
A lighting control signal generating unit that calculates a white point in a complementary color direction with respect to the detected color signal and generates a signal for controlling the lighting device so that the lighting device has an illumination that matches the white point; A lighting control device.   An illumination device comprising the illumination control device according to claim 3.

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