JP2007279339A - Method of projecting image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of projecting an image with a frame image, which eliminates difficulty in viewing the image even when chromaticity, luminance, etc. of the projected image projected on a screen are changed. <P>SOLUTION: The projected image is surrounded with a frame-like image 4, and the color or luminance of the frame-like image 4 is changed in accordance with the color or luminance of an outer peripheral region of the projected image 3. The luminance of the frame-like image 4 is determined by average luminance of the outer peripheral region of the projected image 3 and can be determined by average luminance for a prescribed time. The luminance of the frame-like image 4 is made higher than a prescribed value when the average luminance of the outer peripheral region of the projected image 3 is lower than the prescribed value, and the luminance of the frame-like image 4 is made to be lower than the prescribed value when the average luminance of the outer peripheral region of the projected image 3 is lower than the prescribed value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image projection method for displaying an image projected by a liquid crystal projector or the like surrounded by a frame-like image.

  When an image is enlarged and displayed on a screen using a liquid crystal projector, if the screen itself has a frame, the image is projected into the frame. However, a screen that does not have a frame-like edge or a simple screen that uses a wall surface or the like is often used. When an image is projected on such a screen, depending on the color and brightness of the projected image, the boundary of the projected image becomes unclear and image quality is degraded, making it difficult to see visually. For this reason, when a moving image or a still image is projected and displayed on a large screen like a front projector, a frame-like edge is attached around the image to make the image display area clear and make the image easy to see. Proposed.

For example, Patent Document 1 discloses that an image display area is surrounded by a uniform, clear and clear black area in an enlarged projection type image display apparatus using a light modulation display element. Specifically, a reflective liquid crystal element is used as the light modulation display element, and a uniform light intensity below the minimum value of the light intensity controlled in the image display area is displayed around the image display area. For example, a surrounding area for light shielding is provided.
Japanese Patent Laid-Open No. 9-146075

  Conventionally, as disclosed in the above-mentioned Patent Document 1, as a method of attaching a frame-like edge by image projection around a projection image projected on a screen without a frame, the periphery of the image display area has a certain color. Alternatively, it is common to have a brightness and an appropriate width. However, the color or brightness of the projected image in the image display area is usually not constant, and the projected image is changed or changes with time. In this case, the color and brightness of the projected image may be the same as the color and brightness of the frame-shaped image, and the boundary may be unknown. Even if the colors and brightness are not the same, the hue of the projected image and the frame-shaped image may not match, or the image may be difficult to see depending on the surrounding lighting conditions.

  The present invention has been made in view of the above-described circumstances, and provides an image projection method with a frame image so that the image does not become difficult to see even if the chromaticity, luminance, and the like of the projection image projected on the screen change. Objective.

  An image projecting method according to the present invention is a method for projecting and displaying an image on a screen, surrounding the projected image with a frame-shaped image, and determining the color or luminance of the frame-shaped image as the color of the outer peripheral area of the projected image. Or it changes according to a brightness | luminance. The luminance of the frame-shaped image can be determined by the average luminance of the outer peripheral area of the projection image, and can be determined by the average luminance for a predetermined time. When the average brightness of the outer peripheral area of the projection image is smaller than the predetermined value, the brightness of the frame-like image is made larger than the predetermined value, and when the average brightness of the outer peripheral area of the projection image is larger than the predetermined value, The brightness of the image is made smaller than a predetermined value.

  According to the present invention, the color or brightness of the frame-like image projected on the outer periphery of the projected image changes according to the color or brightness of the outer peripheral area of the projected image, so that the projected image is always conspicuous and easy to see. It becomes possible to do. Further, the color or brightness setting of the frame-shaped image can be calculated in real time from the image data of the input projection image, and can be automatically set.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining an outline of an image projection method according to the present invention, and FIG. 2 is a diagram for explaining a state of pixels for setting a frame-like image. In the figure, 1 is a projector, 2 is a screen, 3 is a projected image, 4 is a frame-shaped image (frame image), 5 is a boundary line, 6 is a pixel for projection image, 7 is a pixel for frame image, and 8 is an outer peripheral area. Indicates.

  The image projection method of the present invention is a method of displaying a projected image from the projector 1 or the like as an enlarged image 3 by copying it on the screen 2. The image 3 projected on the screen 2 can be a still image such as an OHP or a photograph used in a presentation, a moving image such as a TV broadcast or a DVD, and various projected images. . The present invention is to frame the periphery of the projection image 3 with a frame-shaped image 4 (hereinafter referred to as a frame image) in such image projection.

  The frame image 4 is usually a screen using a white board, a white wall, or the like, or other simple screen, and the image of the projection image 3 is clearly defined with respect to the image projected on the screen 2 having no frame. This makes it easy to see the projected image easily and easily. However, when the color and brightness of the projected image 3 change, whether the frame image 4 makes the projected image 3 stand out depends on the difference in the color and brightness of the frame image 4 compared to that of the projected image. . If the frame image 4 and the projected image 3 have the same color and brightness, it is clear that the frame image 4 does not make sense, but how much difference is necessary is also an individual's visual sense. Due to differences, it is difficult to define clearly.

  Further, if the frame image 4 is regarded as a separate image independent of the projection image 3, the color and brightness of the frame image 4 can be appropriately changed by the operator's judgment while viewing the projection image 3. Since it is performed by the operator's sense, it is biased, and the operator is always burdened with monitoring the projection state. Therefore, it is desirable that the color or luminance of the frame image 4 is automatically set so as to have a predetermined color difference or luminance difference according to a change in the color or luminance of the projection image 3.

  Further, in order to form the frame image 4, in the present invention, as shown in FIG. 2, a boundary line 5 between the projection image 3 and the frame image 4 is defined, and pixels that optically convert image data inside the boundary line 5 are defined. Projection image pixels 6 are used, and pixels outside the boundary line 5 are frame image pixels 7. For convenience of explanation, the frame image pixels 7 are shown as one line and one column, but can be defined as a plurality of lines and a plurality of rows as necessary. In addition, although the pixel 7 for frame images allocates the pixel of the outer peripheral part of the existing pixel arrangement | sequence, you may add for frame images.

  In the present invention, image data added to the projection image pixel 6 is used as image data for activating the frame image pixel 7. In this case, it is desirable to use the image data of the projection image 3 for the pixels in the outer peripheral region 8 of the projection image 3. That is, by setting the color or luminance of the projection image pixel 6 in the outer peripheral area 8 of the projection image 3 to the frame image pixel 7 surrounding it, the color difference or luminance difference with the boundary line 5 as a boundary is set. Can do. As a result, the color or brightness of the frame image 4 is related to the color or brightness of the outer peripheral region 8 of the projection image 3, and the projection image 3 can be made clear with the boundary line 5 as a boundary.

  As a specific example in which the image data of the projection image pixel 6 is reflected on the frame image pixel 7, for example, the pixel in the sixth column of the frame image pixel 7 (0 line portion) is the projection image pixel 6. The color or luminance of the average value for a total of nine pixels in the fifth, sixth, and seventh columns of (1, 2, 3 line portion) is set in correspondence. The pixel on the seventh line of the frame image pixel 7 (0th column portion) is the average color of the total of the three pixels on the sixth, seventh, and eighth lines of the projection image pixel 6 (one column portion). Alternatively, the luminance can be set correspondingly.

  As described above, the color or luminance may be determined for each pixel of the frame image pixel 7 by associating the image data of the surrounding projection image pixels 6 with each other. 7 is set to have a uniform color or luminance with reference to the average value of the image data of all 1, 2 and 3 line portions (up to 1 to M columns) of the projection image pixel 6. Also good. Further, with reference to the average value of the image data of all 0 column portions of the frame image pixel 7 and all of the 1, 2, and 3 column portions (1 to N lines) of the projection image pixel 6, uniform colors or The brightness may be set.

  Furthermore, referring to the average value of the image data of the projection image pixels 6 in the outer peripheral portion of the projection image 3 (for example, the upper and lower three lines and the left and right three columns), all the frame image pixels 7 of the frame image 4 are referred to. The color or brightness may be set uniformly. By using the average value of the plurality of image data to uniformly set the entire frame image pixel 7, the calculation load can be reduced and the calculation speed can be increased.

  FIGS. 3A to 4B are diagrams illustrating an example of setting the color or luminance of the frame image 4 by the method described above. FIG. 3A is an image example in which the projected image 3 is a relatively bright image and has a large overall brightness. For example, the average luminance value is calculated from the image data of the outer peripheral area 8 of the projection image 3. Based on this average luminance value, the entire frame image 4 is set with a uniform luminance value. If the average luminance value of the projection image 3 is relatively large and is equal to or greater than a predetermined threshold, the luminance of the frame image 4 is set to a luminance value smaller than the threshold so that the projection image 3 looks brighter.

  FIG. 3B is an example of an image in which the projected image 3 is a relatively dark image and has a low overall brightness. Also in this case, the average luminance value is calculated from the image data of the outer peripheral area 8 of the projection image 3. Based on this luminance value, the entire frame image 4 is set with a uniform luminance value. If the average luminance value of the projection image 3 is relatively small and is equal to or less than a predetermined threshold, the luminance of the frame image 4 is set to a luminance value greater than the threshold, and the darkness of the projection image 3 is further tightened.

  4A, when the projected image 3 has a bright part and a dark part, the brightness value of the frame image 4 in the bright area of the projected image 3 is reduced to make the bright area of the projected image 3 stand out. The brightness value of the frame image 4 in the dark area of the projected image 3 is increased to make the dark area of the projected image 3 stand out. In this way, when the luminance is varied in one frame image 4, as described in FIG. 2, the pixels of the projection image around the pixel unit in the outer peripheral region 8 of the projection image 3 for each pixel unit of the frame image 4. The color or luminance may be determined with reference to the image data, or the frame image 4 may be divided into several small areas to determine the color or luminance.

  FIG. 4B is a diagram for explaining an example in which the projected image 3 is made conspicuous by changing the color of the frame image 4. Regarding the color of the image, elements related to hue, saturation, and lightness are related, but the boundary between the frame image 4 and the projection image 3 can be clarified by making the color difference depending on the degree. As an example of making the colors different, for example, it can be considered that the frame image has a complementary color relationship with the color of the projection image. For example, in FIG. 4B, when the upper half of the sky of the projection image 3 is blue and the lower half of the mountain is green, the upper half of the frame image 4 is yellow, which is a complementary color of blue, and the lower half is green. It is assumed to be purple red, which is the complementary color.

  However, selecting the color of the frame image 4 with a complementary color is merely an example. By giving a color difference depending on the hue, saturation, or brightness of the color, a bright image becomes brighter and a dark image becomes darker. I can do it. This can be realized by the color difference or luminance difference depending on the colors of the projection image 3 and the frame image 4, or by using these together.

  FIG. 5 is a diagram for explaining a configuration example for carrying out the image projecting method according to the present invention. Reference numeral 10 denotes delay means, 11 denotes memory, 12 denotes image clipping means, 13 denotes luminance calculation means, 14 denotes frame luminance determination means, and 15 denotes. Threshold setting means, 16 is a frame image generation means, and 17 is an image composition means. In the example shown in the figure, for example, input image data is supplied from a DVD or the like as a still image or a moving image, output as framed image data, projected onto a screen or the like, and enlarged and displayed.

  The input image data is sent to the delay means 10 for the projection image and input to the memory 11 for the frame image formation. The image cutout unit 12 reads out the projection image from the memory 11 in units of frames. For example, the outer peripheral region of the projection image is cut out and image data of the region is extracted. With respect to the extracted image data, an average value of luminance values in the outer peripheral area of the image is calculated from the luminance calculation means 13. The luminance value can be calculated in a predetermined predetermined area by a pixel unit, a divided small area unit, or an average value of all the set areas. Further, after calculating in units of frames of an image, an average value of a predetermined number of frames (which means a predetermined time) may be calculated.

  The calculated luminance value refers to a predetermined luminance value preset by the threshold setting unit 15, and the frame luminance determining unit 14 determines the luminance value of the frame image suitable for the projection image. When the luminance value of the frame image is determined, the frame image generation means 16 sets the luminance of the color of the frame image and generates a frame image. This frame image is combined with the projection image sent via the delay means 10 by the image synthesizing means 17 and sent as framed image data. Note that the frame image and the projected image may be output separately and combined on the screen.

  FIG. 6 is a diagram illustrating an example of determining the luminance value of the frame image. A predetermined threshold value can be set for the average luminance calculated from the projected image, and the luminance value of the frame image can be set based on this threshold value. That is, if the brightness threshold is set as shown in FIG. 6, if the brightness of the predetermined area of the projection image is smaller (darker) than this threshold, the brightness value of the frame image is set to be slightly larger than this threshold. Apply the offset. Thereby, the effect of tightening the darkness (black) of the image can be provided. On the contrary, if the luminance of the predetermined area of the projection image is larger (brighter) than this threshold, a negative offset is applied so that the luminance value of the frame image is slightly smaller than this threshold. Thereby, the effect of making the brightness (white) of an image stand out more can be given.

  The color or brightness of the frame image can be changed in real time according to the change in the projected image, but if it changes too frequently, it may be difficult to see. Therefore, it is preferable to cause a time delay by giving a hysteresis characteristic to the temporal change in luminance as shown in FIG. Further, by calculating the luminance value by sampling and increasing the sampling interval, the interval of temporal change in the color or luminance of the frame image can be increased.

  FIG. 7 is a diagram showing an outline of the flow of the image projection method according to the present invention. First, in step S101, a luminance calculation area of the projection image is set. As the area to be set, as described with reference to FIG. 2, the outer peripheral area of the projection image is desirable. Next, in step S102, the average luminance in one frame within the set area is calculated. Furthermore, when an image changes like a moving image, the average brightness | luminance in a some flame | frame is calculated in step S103 like a continuous or odd or even frame, and the average brightness | luminance is calculated.

  Next, in step S104, the brightness of the frame image that makes the projected image stand out or emphasizes is determined with reference to a predetermined threshold value or the like. Thereafter, in step S105, a color (fixed or changeable) suitable for the projection image is given as a frame image, and the image is output with the determined luminance. In the case of outputting as an image, the image may be combined with the projected image and output in step S106.

  As described above, in FIG. 5 to FIG. 7, the example in which the luminance value of the frame image is changed based on the luminance data of the projection image has been described. However, instead of the luminance value, color elements such as hue, saturation, brightness, and the like. May be converted into a numerical value, and an average value or the like may be calculated to set the color of the frame image. Further, the luminance value described above may be added and set.

It is a figure explaining the outline of the image projection method by this invention. It is a figure explaining the state of the pixel which sets a frame-shaped image. It is a figure explaining the example which sets the whole frame image by the brightness value of a projection image with the uniform luminance value. It is a figure explaining the example which changes partially the brightness | luminance or color of a frame image according to the partial brightness of a projection image. It is a figure explaining the structural example which implements the image projection method by this invention. It is a figure explaining an example which determines the luminance value of the frame image in this invention. It is a figure which shows the example of a flow of the image projection method by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Screen, 3 ... Projection image, 4 ... Frame-like image (frame image), 5 ... Border line, 6 ... Projection image pixel, 7 ... Frame image pixel, 8 ... Outer peripheral area, 10 ... Delay means, 11 ... Memory, 12 ... Image cutout means, 13 ... Luminance calculation means, 14 ... Frame brightness determination means, 15 ... Threshold setting means, 16 ... Frame image generation means, 17 ... Image composition means.

Claims (5)

  An image projection method for projecting and displaying an image on a screen or the like, wherein the projection image is surrounded by a frame-shaped image, and the color or luminance of the frame-shaped image is changed to the color or luminance of the outer peripheral area of the projection image. An image projecting method, wherein the image projecting method is changed accordingly.   The image projection method according to claim 1, wherein the luminance of the frame-shaped image is determined by an average luminance of an outer peripheral area of the projection image.   The image projection method according to claim 2, wherein the luminance of the frame-shaped image is determined by an average luminance for a predetermined time in an outer peripheral area of the projection image.   4. The image projecting method according to claim 2, wherein when the average luminance of the outer peripheral area of the projected image is smaller than a predetermined value, the luminance of the frame-shaped image is made larger than the predetermined value.   The image projecting method according to claim 2 or 3, wherein when the average luminance of the outer peripheral area of the projected image is larger than a predetermined value, the luminance of the frame-shaped image is made smaller than the predetermined value.

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