Patent Application
20160187967
This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2014-263193, filed on Dec. 25, 2014, the entire contents of which are incorporated herein by reference.
The embodiment discussed herein is related to a video image display device and a video image display method.
In recent years, as one type of wearable terminals to be mounted on bodies and using computing resources, head-mountable video image display devices are known, which each present information on a display that is placed in a visual field of a person wearing the device. Among the video image display devices, there is a monocular video image display device that has a display to be placed in a visual field of one eye of a person wearing the device and has the person recognize information by the single eye.
If the person wears the monocular video image display device, the person recognizes different pictures by both left and right eyes and thus binocular rivalry occurs and causes fatigue.
Traditionally, as measures to suppress binocular rivalry, methods of prioritizing an eye with a visual field in which a display is placed have been considered.
As one of the methods, the following method is known: a method of displaying a video image on a display and prioritizing an eye with a visual field in which the display is placed, by using eye's visual field characteristics in which attention is paid to a motion within a peripheral part of the visual field if the motion within the peripheral part is detected.
For example, a related-art technique is disclosed in “Progress in Study on Binocular Rivalry, Tokyo Institute of Technology, Kazumichi Matsumiya, VISION, Vol. 14, No. 4, 151-164, 2002”.
According to an aspect of the invention, a head-mountable video image display device includes: a display to be placed in a visual field of one of eyes; and a processor coupled to the display and configured to: control the display to display a video image including display information to be gazed by a user, and control the display to display, on the video image, a still image pattern having high and low luminance values and inducing motion illusion.
The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.
In the aforementioned methods, a video image is displayed on a display, but it is difficult to achieve a sufficient frame rate, transmission rate, and information processing capability for the display of the video image in a wearable terminal.
According to an aspect, an object is to provide a video image display device and video image display method that may reduce a process load and power to be consumed.
Hereinafter, an embodiment is described with reference to the accompanying drawings. First, viewpoints to which attention is paid in the embodiment are described with reference to
The pyramidal cells of each eye have the human feel colors and shapes and exist in a central part of a visual field, while the rod cells of each eye sensitively react to positions and motions of objects in an overall wide visual field extending at an angle of ±90 degrees or greater in a horizontal direction. Thus, even if an object moves in an end part of a visual field, the human has visual sense characteristics of becoming aware of the object without recognizing what is the object and turning the eyes and the body to the object so as to try to find out what is the object.
In addition, if patterns are repeatedly displayed on an image with specific high and low luminance values, the human has visual sense characteristics of feeling motions of the patterns that cause motion illusion.
The embodiment pays attention to the aforementioned two types of characteristics. Specifically, in the embodiment, in a monocular video image display device, a process load and power to be consumed are reduced and binocular rivalry is reduced by using human's visual sense characteristics sensitive to a motion and using a still image pattern causing motion illusion to achieve an effect of feeling a motion of an object.
The motion illusion tends to be strong in peripheral parts of a visual field of each eye. Specifically, the motion illusion is strong in peripheral parts of a visual field of each eye that each correspond to a viewing angle greater than approximately 5 degrees and are ranges in which pyramidal cells gather, the eyesight may be applied, and the eyes come into focus.
In the peripheral parts of the visual fields that each correspond to the viewing angle greater than 5 degrees, mosaic perceptual alternation occurs. Thus, in the embodiment, it is preferable that each pattern image be arranged in a respective region corresponding to a viewing angle of 5 degrees in order to prioritize an overall screen in a stable manner.
In addition, humans have visual sense characteristics in which an image having contrast may more strongly induce the adjustment of the focus of the eyes than an image having no contrast and thus may be prioritized.
A pattern image that causes motion illusion has clear boundaries (edges) and has contrast. In the embodiment, by displaying a pattern image on a display, the adjustment of the focus of an eye with a visual field in which the pattern image comes into sight is induced and prioritized.
In general, a virtual distance between the person wearing the monocular video image display device and a virtual image displayed on the display do not match a distance between the person and a certain object that exists in the real world. In this case, if the person who wears the video image display device is able to adjust the focus of an eye that is located on the side of the video image display device, edges seen by the other eye are unclear and the eye that is located on the side of the video image display device is prioritized. Thus, in the embodiment, by displaying the aforementioned pattern image and a virtual image 32 on the display 2, the adjustment of the focus of the right eye of the person who wears the video image display device is induced and the virtual image 32 is prioritized.
A virtual distance L2 between the wearing person and the virtual image 32 displayed on the display 2 of the video image display device 1 is determined based on design values, and it is difficult to match the distance L1 with the virtual distance L2.
In this state, if the wearing person focuses the eye on the display of the video image display device 1, the wearing person does not focus on the object 31. As a result, when the person looks at the object 31 by both eyes, the object 31 looks like an unclear object 31′ as indicated in a visual field 33, and the virtual image 32 on which the eyes focus is prioritized.
Regarding the capability of adjusting the focus, most of all pyramidal cells of each eye that recognize colors and shapes gather in a range corresponding to a viewing angle of approximately ±2.5 degrees, as illustrated in
It is, therefore, desirable that each pattern image according to the embodiment is to be arranged in a respective region corresponding to a viewing angle of 5 degrees.
Hereinafter, the video image display device that is based on the aforementioned two types of characteristics is described. The video image display device 1 according to the embodiment is a monocular video-through head mounted display (HMD).
The video image display device 1 according to the embodiment includes an input device 11, a display device 12, a driving device 13, an auxiliary storage device 14, a memory device 15, an arithmetic processing device 16, and an interface device 17 that are connected to each other by a bus B.
The input device 11 receives data of various types. Specifically, the input device 11 receives an image and video image to be displayed on the display device 12. The display device 12 is the display 2 or the like. For example, the display device 12 according to the embodiment is a display that covers a region corresponding to 10% or more (approximately 20%) of a visual field of one eye of the person wearing the video image display device 1.
The interface device 17 causes the video image display device 1 to be connected to a network. A video image display program is at least a part of various programs for controlling the video image display device 1. The video image display program is provided by the distribution of a storage medium 18 or is downloaded from the network and provided, for example. As the storage medium 18 storing the video image display program, any of various storage media such as storage media that are a CD-ROM, a flexible disk, a magneto optical disc, and the like and are configured to optically, electrically, and magnetically store information and semiconductor memories that are a ROM, a flash memory, and the like and are configured to electrically store information may be used.
If the storage medium 18 storing the video image display program is set in the driving device 13, the video image display program is installed in the auxiliary storage device 14 from the storage medium 18 through the driving device 13. If the video image display program is downloaded from the network, the video image display program is installed in the auxiliary storage device 14 through the interface device 17.
The auxiliary storage device 14 stores the installed video image display program, files, data, and the like. The memory device 15 reads and stores the video image display program from the auxiliary storage device 14 upon the activation of the video image display device 1. Then, the arithmetic processing device 16 achieves various processes (described later) in accordance with the video image display program stored in the memory device 15.
Next, functions of the video image display device 1 are described with reference to
The video image display device 1 according to the embodiment achieves functions of the following units by causing the arithmetic processing device 16 to execute the video image display program. The video image display device 1 according to the embodiment includes an input receiving unit 110, a specific pattern generating unit 120, a video image superimposing unit 130, and a display controlling unit 140.
The input receiving unit 110 according to the embodiment receives the input of a video image to be displayed by the video image display device 1. The video image received by the input receiving unit 110 is to be displayed on the display 2 and includes information to be recognized by the person wearing the video image display device 1.
When the video image is input, the specific pattern generating unit 120 generates a pattern image including repeatedly arranged images having the aforementioned specific high and low luminance values. The video image superimposing unit 130 generates a superimposed video image obtained by superimposing the pattern image on the input video image. The generation of the pattern image by the specific pattern generating unit 120 and the superimposition on the video image by the video image superimposing unit 130 are described later in detail. The display controlling unit 140 controls display of the superimposed video image generated by the video image superimposing unit 130.
When the input receiving unit 110 receives a video image G, the video image display device 1 according to the embodiment causes the specific pattern generating unit 120 to generate a pattern image P1 and causes the video image superimposing unit 130 to superimpose the pattern image P1 at a predetermined position on the video image G. Then, the video image display device 1 causes the display controlling unit 140 to display, on the display 2, the superimposed video image obtained by superimposing the pattern image P1 on the video image G.
Next, the specific pattern generating unit 120 according to the embodiment is described with reference to
The specific pattern generating unit 120 according to the embodiment executes, based on γ characteristics of the display 2, γ correction on luminance values of pixels forming patterns and generates the pattern image.
The display has luminance response characteristics for an input signal, and the signal may not be proportional to the brightness of the screen. In general, it is known that if a luminance value is x (it is assumed that the maximum luminance value is 1) and the brightness of the screen is y (it is assumed that the maximum brightness is 1), the characteristics of the display may be approximated by an equation of (y=xγ). The value of γ varies depending on the type and settings of the display. Normally, if luminance values that are indicated by 256 gray levels are provided to the display, the screen may be dark and the pattern image may not be appropriately displayed.
In the embodiment, in order to generate the pattern image, the γ correction is executed to increase the luminance values and approximate the characteristics of the display to a straight line as much as possible.
The specific pattern generating unit 120 according to the embodiment includes a γ correction table 121, a base pixel holding unit 122, a luminance value correction calculating unit 123, and a drawing unit 124.
The γ correction table 121 is referenced upon the γ correction. The base pixel holding unit 122 holds pixel values corresponding to black, dark gray, white, and light gray regions forming the pattern image.
The luminance value correction calculating unit 123 references the γ correction table 121, corrects the luminance values held by the base pixel holding unit 122, and determines luminance values to be used to finally draw the pattern image. Details of the luminance value correction calculating unit 123 are described later. The drawing unit 124 uses the corrected luminance values to form the pattern image.
Referring to
In
The correction values of the γ correction table 121 illustrated in
Next, operations of the video image display device 1 according to the embodiment are described with reference to
The video image display device 1 according to the embodiment causes the input receiving unit 110 to receive the input of a video image to be displayed on the display 2 (in step S801). Subsequently, the specific pattern generating unit 120 causes the luminance value correction calculating unit 123 to read base pixels held by the base pixel holding unit 122 (in step S802). The base pixels are pixels forming the pattern image and have the luminance values indicated by the 256 gray levels.
Subsequently, the specific pattern generating unit 120 causes the luminance value correction calculating unit 123 to reference the γ correction table 121, correct the luminance values of the base pixels (in step S803), and determine luminance values to be used to draw the pattern image. Then, the specific pattern generating unit 120 causes the drawing unit 124 to draw the pattern image using the luminance values determined in step S803 (in step S804).
Subsequently, the video image display device 1 causes the video image superimposing unit 130 to superimpose the drawn pattern image on the input video image (in step S805) and provide the video image having the pattern image superimposed thereon to the display controlling unit 140. The display controlling unit 140 displays the video image having the pattern image superimposed thereon on the display 2 (in step S806).
The generation of the pattern image by the specific pattern generating unit 120 is described below with reference to
If the luminance of the pattern image according to the embodiment is divided into 4 levels between the minimum luminance (hereinafter referred to as black) and the maximum luminance (hereinafter referred to as white), luminance that is lower than the center value of the luminance of the display is referred to as dark gray, and luminance that is higher than the center value of the luminance of the display is referred to as light gray.
In the embodiment, the motion illusion is induced by repeatedly arranging images of black, dark gray, white, and light gray.
Specifically, the pattern image according to the embodiment includes images of first to fourth luminance whose values are different from each other. If the first luminance (or the minimum luminance)<the second luminance<the third luminance<the fourth luminance (or the maximum luminance), the pattern image is an image in which the image of the first luminance, the image of the second luminance, the image of the fourth luminance, and the image of the third luminance are repeatedly arranged in this order.
The first to fourth luminance values are the luminance values of the base pixels and are held by the base pixel holding unit 122.
It is desirable that differences between the first to fourth luminance values be maintained in the pattern image when the pattern image reaches the eyes of the observing person. The differences between the first to fourth luminance values, however, vary depending on the γ characteristics of the display 2.
Specifically, as illustrated in
In addition, as illustrated in
Even if the pattern image is generated and appropriate for the induction of the motion illusion, the pattern image may not have the differences between the luminance values that are to be originally secured for the pattern image, depending on the γ characteristics of the display, and a sufficient effect may not be obtained.
Thus, the specific pattern generating unit 120 according to the embodiment causes the luminance value correction calculating unit 123 to references the γ correction table 121 and corrects the luminance values held by the base pixel holding unit 122.
The correction of the luminance values by the luminance value correction calculating unit 123 is described below in detail. An example described below assumes that the first, second, third, and fourth luminance values held by the base pixel holding unit 122 are “0”, “54”, “202”, and “255”, respectively.
First, a case where the brightness of the display 2 is set to the “minimum” is described below.
The first luminance value is “0”, and the γ correction table 121 indicates that a correction value when the brightness is 0 or the “minimum” is “0”. Thus, the first luminance value is “0” after the correction.
The second luminance value is “54”. Since the value “54” that is the luminance value of base pixels does not exist in the γ correction table 121, the luminance value correction calculating unit 123 calculates a correction value for the second luminance value by an interpolation method such as linear interpolation.
In this case, the correction value is ((54−48)/(63−31))×(54−31)+48=52. Thus, the luminance value correction calculating unit 123 sets, as a luminance value to be used for the final drawing, a luminance value “106” obtained by adding the correction value “52” to the luminance value 54 of the base pixels.
Similarly, a correction value for the luminance value 202 of base pixels is ((26−14)/(223−191))×(202−191)+14=18. Thus, the luminance value correction calculating unit 123 sets, as a luminance value to be used for the final drawing, a luminance value “220” obtained by adding the correction value “18” to the luminance value “202” of the base pixels.
Similarly, a correction value for the luminance value 255 of base pixels is “0”. Thus, the fourth luminance value is also “255” after the correction.
Specifically, the luminance values of the base pixels are (0, 54, 202, 255). If the brightness of the display 2 is set to the “minimum”, the luminance values for the pixels that are used by the drawing unit 124 for the final drawing are (0, 106, 220, 255).
Next, a case where the brightness of the display 2 is set to the “medium” is described. In this case, the correction value for the second luminance value is ((64−58))/(63−31))×(54−31)+58=62, and the correction value for the third luminance value is ((30−15))/(223−191))×(202−191)+15=20.
Specifically, the luminance values of the base pixels are (0, 54, 202, 255). If the brightness of the display 2 is set to the “medium”, the luminance values of the pixels that are used by the drawing unit 124 for the final drawing are (0, 116, 222, 255).
Next, a case where the brightness of the display 2 is set to the “maximum” is described. In this case, the correction value for the second luminance value is ((72−67))/(63−31))×(54−31)+67=70, and the correction value for the third luminance value is ((32−17))/(223−191))×(202−191)+17=22.
Specifically, Specifically, the luminance values of the base pixels are (0, 54, 202, 255). If the brightness of the display 2 is set to the “maximum”, the luminance values of the pixels that are used by the drawing unit 124 for the final drawing are (0, 124, 224, 255).
As described above, in the embodiment, since the pattern image is displayed on the display 2 after the correction of the luminance values based on the characteristics of the display 2 of the video image display device 1, changes in the gray levels of the pattern image due to the characteristics of the display 2 may be suppressed.
In the embodiment, when the video image G is input to the video image display device 1, the video image superimposing unit 130 superimposes the pattern images P1 on the video image G. In the embodiment, each pattern image P1 is superimposed in a respective region corresponding to a viewing angle of 5 degrees.
In the video image G illustrated in
The pattern images P1 illustrated in
In the example illustrated in
In addition, the video image superimposing unit 130 according to the embodiment may rewrite the pattern images P1 on the video image G in order to superimpose the pattern images P1 on the video image G. Alternatively, the video image superimposing unit 130 may synthesize the pattern images P1 with the video image G by alpha blend. The alpha blend is to make a target image transparent based on a prepared image (mask image) defining a part to be transparent and is to synthesize two images or the target image and another image with each other by a coefficient.
The video image superimposing unit 130 according to the embodiment may superimpose a pattern image on a gap located around a region in which information G1 and G2 is displayed on the display 2 so as to ensure that the region in which the information G1 and G2 is displayed does not overlap the pattern image.
A peak wavelength for the sensitivity of rod cells that represent peripheral parts of a visual field of each eye is 505 nm and corresponds to dark green. If the brightness is expressed by the colors, a mixed color of red and blue that is largely different from green may be a dark color, and a color (for example, yellow) that is close to green may be a light color.
In the pattern images P1′ illustrated in
Thus, regions 102′ of the pattern images P1′ illustrated in
In the examples illustrated in
In the embodiment, pattern images other than the aforementioned pattern images may be used.
In the pattern images P2, 0, 54, 202, and 255 are selected as the luminance values that correspond to black, dark gray, white, and light gray, luminance values between the luminance value 0 corresponding to black and the luminance value 54 corresponding to dark gray are linearly interpolated by interpolation using an interpolant, and luminance values between the luminance value corresponding to dark gray and the luminance value corresponding to white are extrapolated using the interpolant.
The interpolation is to calculate values within interval ranges of a data string of known values based on the data string, while the extrapolation is to calculate values estimated to be outside ranges of data of known values, based on the data.
In the pattern images P2, luminance values between the luminance value 255 corresponding to white and the luminance value 202 corresponding to light gray are linearly interpolated by interpolation using an interpolant, and luminance values between the luminance value corresponding to light gray and the luminance value corresponding to black are extrapolated using the interpolant. In regions 111 included in the pattern images P2 and including white regions and light gray regions, boundaries between black and dark gray and boundaries between white and light gray do not have to be visually recognized.
In the pattern images P2′, purple that is indicated by (R, G, B)=(0x78, 00x00, 0x78) is used instead of dark gray, yellow that is indicated by (R, G, B)=(0xFF, 0xFF, 0x00) is used instead of white, and yellow that is indicated by (R, G, B)=(0xD2, 0xD2, 0x00) is used instead of light gray.
As described above, in the embodiment, by displaying pattern images inducing motion illusion in regions located around regions in which information to be recognized by the wearing person is displayed, an eye with a visual field in which the display 2 of the video image display device 1 is placed may be prioritized. Thus, according to the embodiment, a video image to be used to suppress binocular rivalry may not be displayed and a process load and power to be consumed may be reduced. In addition, in the embodiment, since binocular rivalry may be suppressed, information may be easily recognized.
Although the embodiment describes the case where each pattern image is arranged in a respective region corresponding to a viewing angle of 5 degrees or less, the embodiment indicates that it is preferable that each pattern image be arranged in a respective region corresponding to a viewing angle of approximately 5 degrees, and each viewing angle is not limited to the exact 5 degrees. For example, each pattern image may be displayed on any of the upper, lower, left, and right sides of information to be recognized so as to ensure that each pattern image is arranged in a respective region corresponding to a viewing angle of 5 degrees or less. It is sufficient if the pattern images according to the embodiment are displayed in regions corresponding to viewing angles of approximately 5 degrees at positions at which the pattern images induce motion illusion in the wearing person.
All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiment of the present invention has been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-263193 | Dec 2014 | JP | national |
