KR101366329B1 - Projector and method for image correction - Google Patents

Abstract

The present invention relates to a projector and a method of calibrating the projector. The projector according to the present invention includes a camera formed in a predetermined area of the projector, an image information extracting unit for extracting an image area projected by the projector from the images photographed by the camera and inputting the image information, and the image information input from the image information extracting unit. The image correction control unit for outputting a correction value for correcting the projector image using the display unit and a display unit for displaying the image on the screen by reflecting the correction value output from the image correction control unit. By providing contrast correction, it is possible to provide a projector that prevents deterioration of image quality due to changes in the surrounding environment or discoloration of the projected screen and provides a high quality image.

Projector, camera, image information extractor, brightness correction, contrast correction

Description

Projector and image correction method of the projector {PROJECTOR AND METHOD FOR IMAGE CORRECTION}

1 shows a schematic configuration diagram according to an embodiment of a projector according to the present invention.

2A and 2B illustrate an image projected by a projector and an image captured by a camera in this embodiment.

3A and 3B illustrate a method of extracting an image of a projector from a subject photographed through a camera in an embodiment of the present invention according to FIG. 1.

4 is a view showing another embodiment of a projector according to the present invention.

5 is a flowchart schematically showing an embodiment of a projector image correction method according to the present invention.

6 is a flowchart illustrating a projector image correction method according to another embodiment of the present invention.

Description of the Related Art

10: projector

11: camera

13: image information extraction unit

15: Image correction control unit

17: display unit

The present invention relates to an image correction method of a projector and a projector equipped with an image correction device.

Recently, a large screen and a high-definition display device have emerged as one of the important issues. Until now, such a large-screen display device has been developed and commercialized such as a direct view liquid crystal display, a plasma display, a projection TV, a projector, and the like.

Projection TVs and projectors commonly include a device called an optical engine, and in this optical engine, a cathode ray tube (CRT), a liquid crystal display (LCD), and a digital micro mirror device (DMD) are used to display signal processed image information. Display elements such as

Such a projector adjusts the brightness and contrast of each of the red, green, and blue colors of the input image to project on the screen.

As such, when the image of the projector is projected on the screen, the image of the projector may be affected by changes in the optical environment of the projector such as ambient light, color of the screen, or color change of the projector lamp.

That is, the necessity of adjusting the image of the projector according to the change of the color of the screen or the color of the ambient light or the color of the screen is changed brighter than necessary.

The present invention is to solve the above problems, and to provide a method for correcting the brightness and contrast of the projector image by detecting optical information such as color change of the screen and lamp, lighting around the projector.

In order to achieve the above object, a projector according to the present invention includes a camera formed in a predetermined area of a projector, an image information extracting unit extracting an image area projected by the projector from the image photographed by the camera and inputting the image information into the image information, and the image information. And an image correction controller for outputting a correction value for correcting the projector image by using the image information input from the extraction unit, and a display unit for displaying an image on the screen by reflecting the correction value output from the image correction controller.

The image information extracting unit uses an image of a predetermined region in the image of the photographed subject, or the image information extracting unit sets a projector image region through an image recognition tool in the image of the photographed subject and provides projector image information in the set region. Extract. The image recognition tool may use a field-programmable gate array (FPGA) or a digital signal processor (DPA).

The correction value in the image correction controller is characterized in that for adjusting the brightness or contrast.

The apparatus may further include an angle of view adjusting unit positioned at an input terminal of the camera to adjust an angle of view of the camera to be within an image range projected by the projector.

In addition, the image correction method of the projector according to the present invention for achieving the above object is an image photographing step of photographing a subject including the image projected by the projector, extracting the image area projected by the projector from the image of the photographed subject An image extraction step of inputting the image information, a correction control step of calculating a value for correcting a projector image by using the extracted image information, and a display step of outputting an image by reflecting the value calculated in the correction control step; It is done by

The correction value in the correction control step is characterized in that for adjusting the brightness or contrast of the image.

The image extraction may include extracting image information of a predetermined region from an image of a photographed subject, or setting a projector image region by using an image recognition tool on an image of a photographed subject, and extracting projector image information from the set region. It is done. The image recognition tool may use a field-programmable gate array (FPGA) or a digital signal processor (DPA).

The image photographing step may further include an angle of view adjusting step of preventing a subject of the camera from exceeding an image range projected by the projector by using a separate angle of view adjusting member outside the camera to photograph the image. .

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, the configuration and operation of the present invention will be described in detail through an embodiment of a projector and an image correction method according to the present invention.

1 shows a schematic configuration diagram according to an embodiment of a projector according to the present invention.

As shown in FIG. 1, the projector according to the present invention includes a camera 11, an image information extracting unit 13, an image correction control unit 15, and a display unit 17.

The camera 11 is formed on a portion of the projector 10 to photograph a subject including an image projected by the projector. At this time, the camera 11 is preferably located close to the projection 18 of the projector 10 because it can reduce the error that comes from the mismatch between the center of the projection of the projector and the input of the camera.

The image information extracting unit 13 extracts an image area projected by the projector from the image photographed by the camera and inputs the image information. The image area projected by the projector is an area of the captured image except for the peripheral area of the image projected by the projector, and refers to an area of all or part of the image.

2A and 2B illustrate an image projected by a projector and an image captured by a camera in this embodiment. The range A1 of the subject photographed by the camera 11 may correspond only to an inner region of the image range A2 projected by the projector, but a commonly used camera angle of view θ1 is a projector as shown in FIG. 2A. Since the projection angle θ2 is greater than, the subject A1 photographed by the camera as shown in FIGS. 2A and 2B includes information in the vicinity of the image A2 output from the projector as shown in FIG. 2B. As such, when the surrounding information is used as basic information for correction in addition to the image output from the projector, the brightness or contrast of the projector image cannot be accurately corrected. Therefore, the present invention inputs image information including a projector image by using the camera 11 to correct the image of the projector, and uses the image information extracting unit 13 in the image information of the subject photographed through the camera 11. Extracting and inputting all or part of an image projected by the projector is characterized in that the input.

The image correction controller 15 outputs a value to correct an image of the projector by using the information extracted by the image information extractor 13. In particular, the correction value is characterized by adjusting the brightness (Brightness) or contrast (Contrast) of the projected image. As a method of calculating a value to correct an image, the average of the brightness of the input image information or the average value of the contrast is compared with a predetermined reference value, and the difference is used, or a specific part of the image is used by using a local value among the input image information. You can adjust the brightness and contrast. Since a method of extracting a correction value from the image information may be based on a known method, a detailed description thereof will be omitted.

The display unit 17 displays an image on the screen by reflecting the correction value output from the image correction controller 15. The display unit 17 projects the corrected image by reflecting the correction value to the input main image signal.

3A and 3B illustrate a method in which the image information extracting unit 13 extracts an image of a projector from a subject photographed through a camera in one embodiment of the present invention.

In FIG. 3A, it is shown that the image information extracting unit 13 extracts image information of a predetermined area A3 from image information of the subject A1 captured by the camera 11. Here, the preset area refers to setting a specific area of the image information input by the camera when the project is manufactured. The area is taken by the camera in consideration of the distance between the camera and the projected image by a specific experiment. Set within the range (A2) in which the projector's screen will be located within the image. In this case, the setting area A3 is set to be narrower than the projector image range A2 so as not to be affected by the position or size change of the projector image A2.

For example, the position and size of the image A2 projected by the projector in the image A1 captured by the camera vary depending on the distance between the projector and the projection screen or the projection focus. However, within the range in which the projector is normally used, a change in size or position also changes within a range that can be considered. Therefore, the setting area A3 is set within the area where the projector image is expected to be smaller than the projector image area A2 in consideration of the width of the change. Preferably, it is preferable that the photographing center portion of the camera and the projection center portion of the projector are matched, and the coincided center portion is the center portion of the setting area.

In FIG. 3B, the image information extracting unit 13 sets the projector image region through the image recognition tool from the image information of the photographed subject, and extracts the projector image information from the set region. The image recognition tool refers to an apparatus or a computer program capable of recognizing a projector image from an image photographed by a camera. As the image recognition tool, a well-known field-programmable gate array (FPGA) or digital signal processor (DPA) may be used. According to the present embodiment, there is an advantage that it can be used without being affected by the change in the size or position of the image.

4 is a view showing another embodiment of a projector according to the present invention. The projector shown in FIG. 4 is located in the input unit of the camera 11 in the embodiment shown in FIG. 1 to adjust the angle of view of the camera 11 to be within the image range projected by the projector. It is characterized by further comprising a).

The angle of view adjusting member 41 is positioned at the input end of the camera 11 to adjust the angle of view so that the image A1 ′ photographed by narrowing the angle of view of the camera 11 is located inside the project image area A2. The angle of view adjustment member may be adjusted to the angle of view in a plurality of steps, it can be manufactured to be fixed to a single adjustment step. However, it is desirable to have a single adjustment step for mass production because the smaller the angle of view adjustment step is reduced manufacturing costs. The angle of view adjusting member 41 may be implemented by a combination of a convex lens or a convex lens and a concave lens, and may be formed to be attached to or detached from the camera or the projector.

In the embodiment shown in FIG. 4, since all the images photographed by the camera contain the project image, the image information extracting unit 13 inputs all the image information photographed by the camera as project image information without any manipulation. Since the functions of the image correction controller 15 and the display unit 17 are the same as those of the embodiment of FIG. 1, description thereof will be omitted.

5 is a flowchart schematically showing an embodiment of a projector image correction method according to the present invention.

As shown in FIG. 5, in the projector image correction method according to the present invention, an image information extraction input step (S51) of extracting and inputting all or part of image information projected from a projector using a camera is performed. Compensation control step (S53) for calculating a value to correct the image of the projector by using the display step (S55) for outputting an image reflecting the value to be corrected.

In the image information extraction input step (S51), more specifically, an image capturing step (S51a) of capturing a subject including an image projected by the projector through a camera, and an image area projected by the projector from the entire image information of the photographed subject. And extracting and inputting the image information as image information (S51b). In this case, the image area projected by the projector refers to an area of all or part of the projected image, and refers to an area excluding a peripheral area of the image projected by the projector.

Since the image of the subject photographed by the camera in the image capturing step S51a includes a part other than the projector image as shown in FIG. 2, the subject image photographed in the image capturing step S51a is extracted from the image. In step S51b, all or part of the image projected by the projector is extracted, and the extracted image is input as image information for correction.

As a method of extracting all or part of the image information projected by the projector from the image information of the subject photographed in the image extracting step (S51b), first, a predetermined area in the image information of the photographed subject as shown in FIG. 3A. 3B and a method of setting a projector image region and extracting projector image information from the set region by using an image tool, which is an image, from an image information of a photographed subject. . The image recognition tool may use a field-programmable gate array (FPGA) or a digital signal processor (DPA).

6 is a flowchart illustrating a projector image correction method according to another embodiment of the present invention.

6 illustrates another embodiment of the image capturing step S51a among the steps of the image correcting method of FIG. 5.

The image capturing step (S51a) is an angle of view adjusting step (S61) to prevent the subject of the camera from exceeding the image range projected by the projector by using a separate angle of view adjusting member 41 outside the camera for photographing the subject. It further comprises.

 Referring to FIG. 3, the angle of view adjusting member 41 is positioned at the input end of the camera 11 to narrow the angle of view of the camera 11 so that the image A1 ′ photographed is located inside the project image area A2. Adjust. The angle of view adjusting member 41 may be implemented by a combination of a convex lens or a convex lens and a concave lens, and may be formed to be attached to or detached from the camera or the projector.

In the image information input according to the embodiment of FIG. 6, since all images photographed by the camera contain the project image, the entire image is input as the image information without special manipulation in the image extraction step (S51b), and the input image. Using the information, a correction value for correcting the image of the projector is calculated and output in the correction control step (S53). In the display step S55, an image reflecting the correction value is output. Brightness or contrast of the projected image can be adjusted in the above manner.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments but should be defined by the claims.

As described above, according to the present invention, the camera can be used to correct the brightness or contrast of the image projected by the projector, thereby reducing image quality caused by changes in the surrounding environment or discoloration of the projected screen. Providing a projector that prevents and provides high quality images.

Claims (12)

A camera provided in a predetermined area of the projector; An angle of view adjusting unit positioned at an input of the camera to adjust an angle of view of the camera to be within an image range projected by the projector; An image information extracting unit extracting an image area projected by the projector and inputting the image area from the image photographed by the camera; An image correction controller for outputting a correction value for correcting a projector image by using the image information input from the image information extracting unit; And And a display unit for displaying an image on a screen by reflecting the correction value output from the image correction controller. The method of claim 1, And the image information extracting unit uses an image of a predetermined area in the image of the photographed subject. The method of claim 1, And the image information extracting unit sets a projector image region through an image recognition tool and extracts projector image information from the set region. The method of claim 3, wherein The image recognition tool is a projector, characterized in that using a field-programmable gate array (FPGA) or digital signal processor (DPA). The method of claim 1, The correction value of the image correction controller is characterized in that for adjusting the brightness (Brightness) or contrast (Contrast) of the projected image. The method of claim 1, The angle of view adjustment unit, the projector, characterized in that for adjusting the angle of view so that the image taken by the camera is located inside the project image area located at the input terminal of the camera. An image photographing step of photographing a subject including an image projected by the projector by adjusting an angle of view such that the subject of the camera does not exceed an image range projected by the projector by using an angle of view adjusting member of the camera photographing the image; An image extraction step of extracting an image area projected by the projector from the image of the photographed subject and inputting the image information; A correction control step of calculating a value for correcting a projector image by using the extracted image information; And And a display step of outputting an image by reflecting the value calculated in the correction control step. The method of claim 7, wherein The image extraction step of the image extraction method of the projector, characterized in that for extracting the image information of the predetermined area from the image of the photographed subject. The method of claim 7, wherein The image extracting step includes setting a projector image region using an image recognition tool on an image of a photographed subject and extracting projector image information from the set region. The method of claim 9, The image recognition tool is an image correction method of a projector, characterized in that using a field-programmable gate array (FPGA) or a digital signal processor (DPA). delete The method of claim 7, wherein In the correction control step, the correction value is an image correction method for a projector, characterized in that for adjusting the brightness (Brightness) or contrast (Contrast) of the projected image.

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