JP4553803B2 - Illuminance amplification method and projector - Google Patents

Description

  The present invention relates to an illuminance amplification method for amplifying the illuminance of an achromatic region included in an image when the projector projects an image, and a projector.

  In the field of presentation or video projection, a projector that enlarges and projects an image based on image data onto an external screen or the like is used. Such a projector is configured to generate an image by transmitting or reflecting light with an image device such as a liquid crystal panel or DMD (Digital Micromirror Device), and project the generated image to display the image. . In addition, the projector projects a color image with a three-plate type that includes image devices for each color of R (red), G (green), and B (blue), and synthesizes and projects the images of the respective colors. There is a single plate type that includes a single image device and projects color images by projecting RGB images in a time division manner. A single-plate projector is advantageous in that it is low in cost and easy to miniaturize compared to a three-plate projector including a plurality of image devices.

  The single-plate projector includes a light source that emits white light and a disk-shaped color wheel that is divided into RGB color filters around the rotation axis, and passes light from the light source through the rotating color wheel before being transmitted to the image device. By irradiating, the image device is irradiated with light of RGB colors in a time division manner. The image device generates an image for each color in synchronization with the rotation of the color wheel, and the image of each color is projected in a time division manner. A user who views the image projected by the projector recognizes that the image of each color projected in time division is a color image. In addition, projectors that improve the illuminance of an image by using a color wheel to which a W filter that transmits white light in addition to the RGB color filters is further used.

Some conventional projectors have a so-called white boost function that amplifies the illuminance of an achromatic region included in an image in order to make the image brighter or improve contrast. FIG. 5 is a schematic diagram showing a conventional example of amplifying the illuminance of the achromatic region included in the image. FIG. 5A shows an image including a chromatic region composed of pixels indicating color and light and dark, and an achromatic region composed of pixels indicating only light and dark. FIG. 5B shows the illuminance distribution in the image, the horizontal axis shows the position in the image of each part included in the chromatic region and the achromatic region, and the vertical axis shows the illuminance in each part. When projecting an achromatic image in a time-sharing manner, the projector increases the length of time that light is transmitted or reflected by the imaging device compared to other colors, or the brightness of the light source is compared to other colors. The illuminance in the achromatic region is amplified by a method such as making the image brighter. FIG. 5C shows the illuminance at each part in the image obtained by amplifying the illuminance. While the illuminance at the portion included in the chromatic region is unchanged, the illuminance at each portion included in the achromatic region increases, and the image becomes brighter as a whole. Techniques for amplifying the illuminance of the achromatic region included in the image are disclosed in, for example, Patent Document 1, Patent Document 2, and Patent Document 3.
Japanese Patent Laid-Open No. 10-78550 JP 2004-526992 A Japanese Patent Laid-Open No. 11-6969

  When the projector amplifies the illuminance in the achromatic region included in the image, as described above, the illuminance in the colored region included in the image does not change, and the illuminance in the achromatic region is improved. At this time, the chromatic region included in the image is visually felt as if it is darker than the achromatic region, and there is a problem that the image is visually perceived as dull and less vivid. In addition, in order to avoid this problem, if the illuminance of the colored area is also improved by adding light of a color component different from the color component of each pixel of the originally colored area, such as white light, to the colored area. There is a problem that the saturation and hue in the chromatic area are shifted, and the color quality of the image is deteriorated.

  The present invention has been made in view of such circumstances, and an object of the present invention is to achieve achromatic areas while suppressing a decrease in vividness of a colored area included in an image and a decrease in color quality of the image. It is an object to provide an illuminance amplification method and a projector that can amplify the illuminance at the projector.

An illuminance amplification method according to the present invention is a method for amplifying the illuminance of an achromatic region among a chromatic region and an achromatic region included in a projected image by a projector that projects an image based on the image data. Based on the above, the pixels in the chromatic area and the pixels in the achromatic area included in the image are detected, and for each pixel in the detected achromatic area, the relative distance to the pixel in the closest chromatic area is obtained and obtained. Based on the magnitude of the relative distance, each pixel in the achromatic region is classified into a plurality of types according to the relative distance, and the achromatic region included in the image is classified into the plurality of types. is divided into a plurality of parts made of the amount of amplification of irradiance in each part divided, so that the relative distance from each portion to chromatic region is small enough is small, different values among the plurality of partial I decided to, decision And wherein the amplifying the illumination intensity at each part of the achromatic region included in an image by the amount of amplification.

The projector according to the present invention includes means for projecting an image based on the image data, and illuminance amplifying means for amplifying the illuminance of the achromatic area among the chromatic and achromatic areas included in the image projected by the means. In the projector, on the basis of the image data, a means for detecting a pixel in the chromatic area and a pixel in the achromatic area included in the image, and the closest chromatic area for each pixel in the achromatic area detected by the means Means for determining a relative distance to a pixel in the device, and means for classifying each pixel in the achromatic region into a plurality of types according to the relative distance based on the magnitude of the relative distance obtained by the means; the achromatic region included in the image, and hand stage you divided into a plurality of parts consisting of the classified pixels to said plurality of types, amplification of illumination the illumination amplifying means in each portion where該手 stage is divided to amplify amount , So that the relative distance from each portion to chromatic region is small enough is small, characterized in that it comprises a manual step that determine the different values between the plurality of portions.

  In the present invention, in a projector that projects an image including a chromatic region and an achromatic region, when amplifying the illuminance of the achromatic region, the amplification amount according to the relative distance from each part in the achromatic region to the chromatic region Thus, the illuminance at each part in the achromatic region is amplified step by step.

  In the present invention, the relative distance from the pixels in the achromatic region to the pixels in the closest chromatic region included in the image projected by the projector is not included in a plurality of portions having different relative distances to the chromatic region. Divide the coloring area.

  In the present invention, the projector amplifies the illuminance in the achromatic region step by step so that the illuminance amplification amount becomes smaller as the distance to the chromatic region in the image becomes smaller.

  The projector according to the present invention includes a means for determining a signal level of image data corresponding to the brightness of an image, and the illuminance amplification for an image for which the signal level determined by the means is less than a predetermined reference level. And a means for prohibiting the means from amplifying the illuminance.

  Further, in the present invention, the projector determines the signal level of the image data corresponding to the brightness of the image, and prohibits the amplification of illuminance when the signal level does not reach the reference level.

  In the present invention, when amplifying the illuminance of the achromatic region with a projector that projects an image including the chromatic region and the achromatic region, each of the achromatic regions in the achromatic region with an amplification amount corresponding to the relative distance to the chromatic region. By amplifying the illuminance at the portion, the entire image can be brightened without excessively brightening the portion near the coloring region.

  Further, in the present invention, the relative distance from each pixel in the achromatic region included in the image projected by the projector to the pixel in the closest chromatic region is obtained and classified into a plurality of types based on the obtained relative distance. By dividing the achromatic region into a plurality of portions made up of pixels, the achromatic region can be divided into a plurality of portions having different relative distances to the chromatic region.

  In the present invention, the illuminance of the achromatic region is increased by amplifying the illuminance of the achromatic region so that the smaller the relative distance from the chromatic region is, the smaller the amplification amount of the illuminance is. It is possible to alleviate a state in which the chromatic area is visually felt as if it has become darker than the surroundings without performing, and to suppress the dullness of the chromatic area and the decrease in vividness. Accordingly, it is possible to improve the brightness of the image projected by the projector while suppressing the decrease in the vividness of the coloring area and the decrease in the white quality of the image.

  Furthermore, in the present invention, it is possible to effectively brighten the image by amplifying the illuminance in the range where the signal level of the image data corresponding to the brightness of the image projected by the projector is equal to or higher than the reference level, etc. The present invention has an excellent effect.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
FIG. 1 is a block diagram showing an internal configuration of a projector 1 according to the present invention. White arrows in the figure indicate light. The projector 1 includes a light source 11 such as a metal halide lamp that emits white light, a color wheel 12 that allows light from the light source 11 to pass through, an image device 13 that generates an image composed of reflected light or transmitted light, and an image device 13. And an optical system 14 for enlarging the generated image and projecting it to the outside. The color wheel 12 is formed in a disk shape and is configured to be rotatable, and is provided with a plurality of filters that transmit light of specific colors around the rotation axis. The color wheel 12 is made up of four filters of RGBW, in which a filter of W for passing white light is added to a filter of three colors of RGB for passing light of each color of RGB from white light. The image device 13 uses a liquid crystal panel, DMD, or the like, and is configured to generate RGBW color images in a time-sharing manner. The optical system 14 includes a projection lens, a motor for adjusting the position of the projection lens, a drive circuit for driving the motor, and the like.

  The projector 1 irradiates the image device 13 with light from the light source 11 through the color wheel 12, generates an image composed of reflected light of the light irradiated by the image device 13, and outputs the generated image to the outside through the optical system 14. By projecting, an image composed of light is projected onto an external screen or a wall. In addition, it is good also as a structure which produces | generates an image by allowing the light from the light source 11 to pass through instead of reflecting on the image device 13. FIG. The projector 1 projects a color image by generating an image with light passing through filters of each color constituting the color wheel 12 and projecting an image of each color in a time division manner. The projector 1 can also project an image in which a colored chromatic region and an achromatic region made up of light and dark colors are mixed, or an image made up of only an achromatic region.

  The projector 1 also includes a control unit 21 including a processor that performs calculation, a ROM that stores information such as a program necessary for the calculation, and a RAM that stores temporarily generated information. The control unit 21 performs processing for controlling the overall operation of the projector 1. The projector 1 also includes a color wheel driving unit 22 including a motor that rotates the color wheel 12 and a control circuit that controls the rotation speed of the color wheel 12. The color wheel driving unit 22 is connected to the control unit 21. Yes. The image device 13 is connected to an image device drive circuit 23 that performs processing for forming a necessary image on the image device 13, and the image device drive circuit 23 is connected to the control unit 21. The control unit 21 controls the operation of the color wheel driving unit 22 to appropriately drive the color wheel 12 and controls the operation of the image device driving circuit 23 so that an image based on the image data can be projected to the outside. The image device 13 is configured to perform processing for forming an appropriate image.

  The projector 1 also includes a receiving unit 25 that receives image data transmitted from an external device such as a personal computer (PC) or a video reproduction device. The receiving unit 25 detects the signal level of the image data corresponding to the brightness of the image, and further determines whether or not the image data includes data corresponding to achromatic pixels. It is connected. The signal level detection unit 24 is connected to the control unit 21 and inputs the image data received by the reception unit 25 to the control unit 21, and includes signal level detection results and data corresponding to achromatic pixels. It is configured to input a determination result as to whether or not the control has been performed.

  The signal level detection unit 24 detects pixel information for detecting information on pixels in the chromatic area and achromatic area included in the image for one frame from image data for forming an image for one frame. The unit 28 is connected. In addition, the pixel detection unit 28 obtains a relative distance from each pixel in the achromatic region to the nearest pixel in the achromatic region by calculating a relative distance to each pixel in the achromatic region. A position determination unit 27 for determining a correct position is connected. Further, an achromatic color region dividing unit 26 that divides the achromatic color region into a plurality of portions based on the relative distance obtained by the position determining unit 27 is connected to the position determining unit 27. The achromatic color region dividing unit 26 is connected to the control unit 21.

  The achromatic color region dividing unit 26 stores a range of a plurality of types of relative distance values obtained by dividing continuous relative distance values with a predetermined threshold as a boundary, and a color closest to each pixel in the achromatic color region Based on which range the relative distance to the pixels in the region is included, the pixels in the achromatic region are classified into a plurality of types of pixels, and the achromatic region is divided into portions composed of each type of pixel. The achromatic color area dividing unit 26 inputs information indicating a plurality of types of parts obtained by dividing the achromatic color area to the control unit 21. In this way, the pixel detection unit 28, the position determination unit 27, and the achromatic color region dividing unit 26 are configured to function as a dividing unit according to the present invention.

  The control unit 21 sets the amplification amount of illuminance corresponding to the relative distance from each part of the achromatic region to the chromatic region, and applies to each part in the achromatic region divided by the achromatic region dividing unit 26. On the other hand, the amount of illuminance amplification is determined in accordance with the set contents. The illuminance amplification amount stored by the control unit 21 is such that the illuminance amplification amount becomes smaller as the relative distance from the pixel in the portion into which the achromatic region is divided to the pixel in the closest chromatic region is smaller. It is set. Further, the control unit 21 controls the operations of the color wheel driving unit 22 and the image device driving circuit 23, and passes through the W filter of the color wheel 12 at each part on the image device 13 corresponding to each part of the achromatic region. The illuminance at each part in the achromatic region included in the image is amplified by increasing the length of time for reflecting the reflected light according to the determined amount of illuminance amplification. Thus, the control unit 21 is configured to function as an illuminance amplification unit and an amplification amount determination unit according to the present invention.

  Next, the content of the illuminance amplification method executed by the projector 1 having the above-described configuration will be described. FIG. 2 is a flowchart showing a procedure of processing for generating an image in which the projector 1 of the present invention amplifies the illuminance of the achromatic region. The receiving unit 25 receives image data for one frame for generating an image (S1). The signal level detection unit 24 determines whether the image data received by the reception unit 25 includes data corresponding to achromatic pixels (S2). When the image data includes data corresponding to achromatic pixels (S2: YES), the signal level detection unit 24 uses the reference level in which the signal level of the image data corresponding to the brightness of the image is determined in advance. It is determined whether or not this is the case (S3).

  If the image data does not include data corresponding to achromatic pixels in step S2 (S2: NO), or if the signal level of the image data corresponding to the brightness of the image is less than the reference level in step S3 (S3: NO), the signal level detection unit 24 inputs the determination result to the control unit 21, and the control unit 21 controls the color wheel driving unit 22 and the image device driving circuit 23 on the basis of the image data, thereby adjusting the illuminance. An image is generated by the image device 13 without amplification (S10). The projector 1 projects the generated image and ends the process of generating an image for one frame, and the receiving unit 25 receives image data for the next frame.

  If the signal level of the image data corresponding to the brightness of the image is equal to or higher than the reference level in step S3 (S3: YES), the pixel detection unit 28 determines from the image data the color region included in the image based on the image data. The information of the pixels within and the pixels within the achromatic region is detected (S4). Next, the position determination unit 27 determines, for each pixel in the achromatic region included in the image, a relative distance from the pixel to the pixel in the closest color region (S5). Next, the achromatic color region dividing unit 26 determines whether the relative distance from each pixel in the achromatic color region to the pixel in the nearest chromatic region is included in the range of the relative distance value stored therein. Is determined, the pixels in the achromatic region are classified into a plurality of types according to the relative distances to the pixels in the nearest chromatic region (S6), and the pixels in the plurality of types of pixels are not classified. The coloring area is divided (S7). Next, the control unit 21 sets the achromatic color region so that the illuminance amplification amount decreases as the relative distance from the pixel in the portion into which the achromatic color region is divided to the pixel in the closest colored region is smaller. The amount of illuminance amplification in each divided part is determined (S8).

  Next, the control unit 209 increases the length of time for reflecting the light that has passed through the W filter of the color wheel 12 in each part on the image device 13 corresponding to each part of the achromatic region in accordance with the amplification amount. By controlling the operation of the color wheel drive unit 22 and the image device drive circuit 23 so that the illuminance of each part in the achromatic region is amplified with the determined amplification amount, the amplification amount becomes smaller as the color region is closer. The image device 13 is caused to generate an image obtained by amplifying the illuminance in the achromatic region (S9). The projector 1 thus generates an image while amplifying the illuminance of the achromatic region, projects the generated image, ends the processing of generating an image for one frame, and the receiving unit 25 performs the next one frame. Minute image data is received.

  FIG. 3 is a schematic characteristic diagram illustrating an example of the amount of illuminance amplification set by the control unit 21. In the drawing, the illuminance value with respect to the signal level of the image data corresponding to the brightness of the pixels included in the image is shown, the horizontal axis indicates the signal level, and the vertical axis indicates the illuminance. The illuminance that simply increases with respect to the signal level when the illuminance is not amplified is indicated by a solid line. An example of the amplified illuminance is indicated by a one-dot chain line, and the illuminance increases as the signal level increases with a larger change than in the case of the solid line without amplification. An example of illuminance amplified with a larger amplification amount is indicated by a broken line. Amplification of illuminance is performed in a range where the signal level is equal to or higher than the reference level. By amplifying the illuminance in a range where the signal level of the image data is equal to or higher than a certain reference level, the image can be effectively brightened. For example, the control unit 21 sets the illuminance at the portion closest to the chromatic area to 0 as shown by the solid line, and the illuminance at the portion farther from the chromatic area to the amplification as shown by the dashed line, Furthermore, by setting the amplification amount of the illuminance in the portion far from the chromatic area to the amplification amount as shown by the broken line, the illuminance amplification amount in each part in the achromatic region is smaller as the relative distance to the chromatic region is smaller. It is set to be.

  FIG. 4 is a schematic diagram showing an example of an image obtained by amplifying illuminance using the illuminance amplification method of the present invention. FIG. 4A shows an image composed of a chromatic region and an achromatic region, and the achromatic region is divided into a first portion that is closest to the chromatic region, a second portion, and a third portion that is farthest from the chromatic region. An example is shown. FIG. 4B shows the illuminance distribution in the image, the horizontal axis shows the position in the image, and the vertical axis shows the illuminance at each position. The first portion closest to the chromatic area has an illuminance amplification amount of 0 and is darker than the chromatic area. The illuminance of the second part farther from the coloring region than the first part is amplified compared to the first part. Further, the illuminance of the third part farther from the coloring area than the second part is amplified compared to the second part. Thus, without increasing the illuminance of the achromatic region by amplifying the illuminance of the achromatic region so that the illuminance amplification amount becomes smaller as the relative distance from the chromatic region is smaller, the process of improving the illuminance of the colored region is also performed. It is possible to alleviate a state in which the coloring area is visually felt as if it is darker than the surrounding area, and to suppress the dullness of the coloring area from being dull and decreasing in vividness. Therefore, by using the present invention, it is possible to improve the brightness of the image projected by the projector 1 while suppressing the decrease in the vividness of the coloring area and the decrease in the white quality of the image.

  In the present embodiment, the projector 1 according to the present invention is described as having the color wheel 12 composed of four RGBW filters, but the present invention is not limited to this, and a color composed of a larger number of filters. The form provided with the wheel may be sufficient and the form provided with the color wheel which consists of a filter of three colors of RGB may be sufficient. When the projector 1 has a color wheel made up of three color filters of RGB, the image device 13 generates an image using light that has passed through the boundary of each filter, and thereby the illuminance of the achromatic region Can be amplified.

  In the present embodiment, as an illuminance amplification method according to the present invention, a method of amplifying illuminance by changing a change curve of illuminance with respect to the signal level of image data has been described. It is not a thing, but each method with a specific amplification factor corresponding to each part which divided the achromatic region, or a method of uniformly amplifying the illuminance in each part with a specific amplification amount corresponding to each part which divided the achromatic region The form using the method of amplifying the illuminance at the part may be used. In the present embodiment, as an illuminance amplification method according to the present invention, a method has been described in which an achromatic region is divided into a plurality of parts and illuminance is amplified at each part. The illuminance in the achromatic region is continuously reduced while the illuminance amplification amount becomes smaller as it is closer to the chromatic region, such as by linearly matching the relative distance to the chromatic region and the illuminance amplification amount. Alternatively, a method using a method of amplifying automatically may be used.

  In the present embodiment, the projector 1 according to the present invention is configured to receive image data from the outside. However, the present invention is not limited to this, and receives a broadcast signal such as an analog or digital television broadcast. Alternatively, a tuner that generates image data may be provided. In addition, the projector 1 includes an input unit (not shown) through which various processing instructions are input by a user's operation, and the setting content and control content in the control unit 21 can be changed according to the setting instruction input to the input unit. Form may be sufficient.

  In the present embodiment, the projector according to the present invention shows a mode in which an image is projected onto an external screen or the like. However, the present invention is not limited to this, and includes a transmissive screen (not shown) from the back of the screen. A rear projection type projector that projects an image on the screen by projecting an image with the optical system 14 may be used.

It is a block diagram which shows the internal structure of the projector of this invention. It is a flowchart which shows the procedure of the process which the projector of this invention produces | generates the image which amplified the illumination intensity of the achromatic region. It is a typical characteristic figure which shows the example of the amplification amount of the illumination intensity which the control part has set. It is a schematic diagram which shows the example of the image which amplified the illumination intensity using the illumination intensity amplification method of this invention. It is a schematic diagram which shows the prior art example which amplifies the illumination intensity of the achromatic region contained in an image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projector 11 Light source 12 Color wheel 13 Image device 21 Control part 24 Signal level detection part 26 Achromatic color area division part 27 Position determination part 28 Pixel detection part

Claims (3)

In a method for amplifying the illuminance of an achromatic color region in a chromatic region and an achromatic color region included in a projected image in a projector that projects an image based on image data,
Based on the image data, detect pixels in the chromatic area and achromatic area included in the image,
For each pixel in the detected achromatic region, find the relative distance to the pixel in the closest chromatic region,
Based on the magnitude of the obtained relative distance, each pixel in the achromatic region is classified into a plurality of types according to the relative distance,
Dividing the achromatic region included in the image into a plurality of portions composed of pixels classified into the plurality of types ;
The amount of illuminance amplification in each divided part is determined to be different from each other between the plurality of parts so that the relative distance from each part to the coloring region is smaller .
An illuminance amplification method characterized by amplifying the illuminance at each portion in the achromatic region included in the image with the determined amplification amount. In a projector comprising means for projecting an image based on image data, and illuminance amplifying means for amplifying the illuminance of the achromatic area among the chromatic and achromatic areas included in the image projected by the means,
Means for detecting pixels in the chromatic region and pixels in the achromatic region included in the image based on the image data;
Means for obtaining a relative distance to each pixel in the achromatic region detected by the means for each pixel in the achromatic region;
Means for classifying each pixel in the achromatic region into a plurality of types according to the relative distance based on the magnitude of the relative distance obtained by the means;
The achromatic region included in the image, and hand stage you divided into a plurality of parts consisting of the classified pixels to said plurality of types,
The amplification amount of illumination該手 stage amplifying said illuminance amplifying means in each part divided, so that the relative distance from each portion to chromatic region is small enough is small, mutually different among the plurality of partial projector, characterized in that it comprises a manual step that determine the value. Means for determining the signal level of the image data corresponding to the brightness of the image;
3. The image processing apparatus according to claim 2 , further comprising: a unit that prohibits the illuminance amplification unit from amplifying the illuminance for an image in which the signal level determined by the unit is less than a predetermined reference level. Projector.

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