阅读说明：本技术 在头戴式设备中的柔性显示设备上显示图像的方法和对应的装置 (Method for displaying images on a flexible display device in a head mounted device and corresponding apparatus ) 是由 P.安德里文 F.加尔平 F.厄本 于 2020-03-18 设计创作，主要内容包括：定义了用于在头戴式设备(HMD)中的柔性显示器上显示图像的方法和装置。一个或多个柔性显示设备可以插入到HMD中。一个或多个柔性显示设备可以被HMD约束以采取特定弯曲形式并且翘曲在一个或多个柔性显示设备上显示的图像的视场(FOV)以改善用户体验。一个或多个柔性显示器的显示表面可以划分为显示区域,显示区域对应于焦点区域和外围FOV。图像处理可以根据显示区域进行区分。(Methods and apparatus for displaying images on a flexible display in a Head Mounted Device (HMD) are defined. One or more flexible display devices may be inserted into the HMD. The one or more flexible display devices may be constrained by the HMD to take a particular curved form and warp a field of view (FOV) of an image displayed on the one or more flexible display devices to improve a user experience. The display surface of the one or more flexible displays may be divided into display areas, the display areas corresponding to the focal area and the peripheral FOV. The image processing may be differentiated according to the display area.)

1. A method (1300) for rendering images on at least one flexible display device in a head mounted device, the method comprising:

configuring (1301) image processing features of an image to be rendered on the at least one flexible display device in accordance with a first display area of the at least one flexible display device on which the image is to be rendered and a second display area of the at least one flexible display device on which the image is to be rendered, the second display area surrounding the first display area and the first display area corresponding to a focus field of view and the second display area corresponding to a peripheral field of view, and

rendering (1302) an image on the first display area and the second display area of at least one flexible display device according to the configured image processing features.

2. The method of claim 1, wherein the head mounted device includes an opening configured to receive the at least one flexible display device for insertion of the at least one flexible display device into the head mounted device, the head mounted device constraining the at least one flexible display device to assume a curved form when the at least one flexible display device is inserted into the head mounted device.

3. The method of claim 2, further comprising determining a size and a position of the first display area and the second display area based on the curved form and a size of the at least one flexible display device.

4. The method of any of claims 1 to 3, wherein the image processing feature comprises at least one of:

applying higher spatial and/or temporal resolution image processing to images to be rendered on the first display region than to images to be rendered on the second display region;

applying a warping transform to an image to be rendered on the first display area in accordance with the curved form to correct distortion caused by a lens in the head mounted device, and not applying the warping transform to an image to be rendered on the second display area;

extending an image to be rendered on the first region to the second region by extracting image features from an outer display region of the image to be rendered on the first region.

5. The method of claim 3, wherein the size and position of the first and second display areas is further according to:

A focal length of a set of lenses included in the head-mounted device;

a focal center distance between a set of lenses included in the head mounted device;

eye-to-display distance;

display-to-lens distance;

an interpupillary distance of a user of the head-mounted device.

6. The method of claim 5, wherein the interpupillary distance is measured by the at least one flexible display device based on a sensor element in the at least one flexible display device.

7. A flexible display device (1500) for rendering an image when inserted in a head mounted device, the flexible display device comprising at least one processor (1501) configured to:

configuring image processing features of an image to be rendered on a flexible display in accordance with a first display area of the flexible display device on which the image is to be rendered and in accordance with a second display area of the flexible display device on which the image is to be rendered, the second display area surrounding the first display area and the first display area corresponding to a focal field of view and the second display area corresponding to a peripheral field of view; and

rendering an image on the first display area and the second display area of the flexible display device according to the configured image processing features.

8. The flexible display device of claim 7, the head-mounted device comprising an opening configured to receive the flexible display device for insertion of the flexible display device into the head-mounted device, the head-mounted device constraining the flexible display device to assume a curved form when the flexible display device is inserted into the head-mounted device, the processor further configured to:

determining the size and position of the first display area and the second display area according to the curved form and the size of the at least one flexible display device.

9. The flexible display device according to claim 7 or 8, wherein the processor is further configured to apply at least one of the following image processing features:

applying higher spatial and/or temporal resolution image processing to images to be rendered on the first display region than to images to be rendered on the second display region;

applying a warping transform to an image to be rendered on the first display area in accordance with the curved form to correct distortion caused by a lens in the head mounted device, and not applying the warping transform to an image to be rendered on the second display area;

Extending an image to be rendered on the first region to the second region by extracting image features from an outer display region of the image to be rendered on the first region.

10. The flexible display device of claims 7-9, wherein the processor is further configured to obtain an interpupillary distance from a user of the head mounted device for determining a center position of the first region.

Technical Field

The present disclosure relates generally to the field of head mounted devices.

Background

Any background information described herein is intended to introduce the reader to various aspects of art, which may be related to the present embodiments described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light.

Head mounted displays or Head Mounted Devices (HMDs) provide a user with the impression of immersion in a three-dimensional (3D) environment and are used, for example, in augmented and virtual reality (AR/VR) systems. Mid-to-high end HMDs include one display (monocular HMD) or two displays (e.g., one display per eye (binocular HMD)). These displays typically have curvature in order to provide minimal visual distortion and achieve a user experience comparable to real world vision. When the image to be rendered on the HMD is initially intended to be displayed on a display device having a flat surface, image processing may be used to adapt the image(s) to the curved display(s) of the HMD in order to avoid visual artifacts that may adversely affect the user experience and may cause discomfort. The image processing is specific to each HMD and is provided with the HMD. A low cost HMD may include a frame that may be provided with an arrangement for receiving a mobile phone ("smartphone-based HMD"). The mobile phone may have a flat display surface. Using a flat display surface for the HMD may result in a distorted image, which may be at least partially compensated for by processing the image for display (e.g., by deforming the image as if it warped on an imaginary curved surface). However, the quality of the user experience is still lower than in mid-high HMD comprising a fixed curved display. The advent of mobile devices with flexible displays ("flexible display devices") created opportunities for improving the user experience of low cost HMDs.

Disclosure of Invention

According to one aspect of the present disclosure, a method for rendering images on at least one flexible display device in a head mounted device is provided. The method comprises the following steps: configuring image processing characteristics of an image to be rendered on the at least one flexible display device according to a first display area of the at least one flexible display device on which the image is to be rendered and a second display area of the at least one flexible display device on which the image is to be rendered, the second display area surrounding the first display area and the first display area corresponding to the focal field of view and the second display area corresponding to the peripheral field of view, and rendering the image on the first display area and the second display area of the at least one flexible display device according to the configured image processing characteristics.

According to another aspect of the method, the head mounted device includes an opening configured to receive the at least one flexible display device for insertion of the at least one flexible display device into the head mounted device, the head mounted device constraining the at least one flexible display device to assume a curved form when the at least one flexible display device is inserted into the head mounted device.

According to another aspect of the method, the method further comprises determining the size and position of the first display area and the second display area based on the curved form and the size of the at least one flexible display device.

According to another aspect of the method, the image processing features include at least one of: applying a higher temporal and/or spatial resolution image processing to the image to be rendered on the first display region than to the image to be rendered on the second display region; applying a warping transform to an image to be rendered on a first display area according to a curved form to correct distortion caused by a lens in a head mounted device, and not applying the warping transform to the image to be rendered on a second display area; an image to be rendered on a first region is expanded to a second region by extracting image features from an outer display region of the image to be rendered on the first region.

According to another aspect of the method, the size and position of the first display area and the second display area are further based on: a focal length of a set of lenses included in the head-mounted device; a focal center distance between a group of lenses; eye-to-display distance; display-to-lens distance; an interpupillary distance of a user of the head-mounted device.

According to another aspect of the method, the interpupillary distance is measured by the at least one flexible display device based on the sensor element in the at least one flexible display device.

According to another aspect of the method, the at least one flexible display device obtains the property of the head mounted device by reading a quick response code associated with the head mounted device.

According to another aspect of the method, the at least one flexible display device obtains the property of the head mounted device by reading a near field communication tag incorporated in the head mounted device.

The present disclosure also relates to a flexible display device for rendering an image when inserted in a head mounted device, the flexible display device comprising a processor configured to: configuring image processing features of an image to be rendered on the flexible display device in accordance with a first display area of the flexible display device on which the image is to be rendered and in accordance with a second display area of the flexible display device on which the image is to be rendered, the second display area surrounding the first display area and the first display area corresponding to the focal field of view and the second display area corresponding to the peripheral field of view; and rendering an image on the first display area and the second display area of the flexible display device according to the configured image processing features.

According to another aspect of the flexible display device, the head mounted device includes an opening configured to receive the flexible display device for insertion of the flexible display device into the head mounted device, the head mounted device constraining the flexible display device to assume a curved form when the flexible display device is inserted into the HMD, the processor further configured to: the size and position of the first display area and the second display area are determined according to the curved form and the size of the at least one flexible display device.

According to another aspect of the flexible display device, the processor is further configured to apply at least one of the following image processing features: applying a higher spatial and/or temporal resolution image processing to the image to be rendered on the first display area than to the image to be rendered on the second display area; applying a warping transform to an image to be rendered on a first display area according to a curved form to correct distortion caused by a lens in a head mounted device, and not applying the warping transform to the image to be rendered on a second display area; an image to be rendered on a first region is expanded to a second region by extracting image features from an outer display region of the image to be rendered on the first region.

According to another aspect of the flexible display device, the processor is further configured to obtain an interpupillary distance from a user of the head mounted device for determining a center position of the first region.

According to another aspect of the flexible display device, the processor is further configured to obtain the interpupillary distance from a sensor element in the flexible display device.

According to another aspect of the flexible display device, the processor is further configured to determine a form of the bend upon insertion of the flexible display device into the head-mounted device.

According to another aspect of the flexible display device, the processor is further configured to obtain an attribute of the head mounted device from a quick response code reader in the flexible display device, read a quick response code associated with the head mounted device.

According to another aspect of the flexible display device, the flexible display device is a mobile communication device.

According to another aspect of the flexible display device, the mobile communication device is a smartphone.

Drawings

Further advantages of the present disclosure will emerge from the description of specific, non-limiting embodiments. In order to describe the manner in which the advantages of the present disclosure can be obtained, a particular description of the present principles is presented with reference to specific embodiments thereof which are illustrated in the accompanying drawings. The drawings depict exemplary embodiments of the present disclosure and are not therefore to be considered to be limiting of its scope. The described embodiments may be combined to form certain advantageous embodiments. In the following figures, items having the same reference numerals as items already described in previous figures will not be described again to avoid unnecessarily obscuring the present disclosure. Embodiments will be described with reference to the following drawings, in which:

fig. 1a is a prior art HMD with a slot for inserting a display device.

Fig. 1b is a top view of the prior art HMD of fig. 1 a.

Fig. 2a is an HMD according to an embodiment.

Fig. 2b is a top view of the same HMD of fig. 2 a.

Fig. 3 a-3 c are embodiments of an HMD receiving a single flexible display, which may take the form of a bend.

Fig. 4 a/4 b are embodiments in which the HMD is configured to receive two flexible display devices.

Fig. 5 a-5 c illustrate the use of multiple flexible displays, such as in the HMD of fig. 4 a/4 b, and in particular the definition of the display area in such embodiments.

Fig. 6a and 6b show an embodiment using a single flexible display and constrained by the HMD to take the form of a double bend once inserted.

Fig. 7a to 7c show how regions are defined in the display area of a single flexible display.

Fig. 8 a/8 b illustrate a particular embodiment of image processing according to region differentiation.

Fig. 9 a/9 b illustrate another particular embodiment of image processing according to region differentiation.

Fig. 10a illustrates visual distortion of an image displayed on a flexible display device, which may be observed by a user of an HMD equipped with one or more lenses.

Fig. 10b illustrates how the distortion of fig. 10a is corrected.

Fig. 11 is a diagrammatic representation illustrating the determination of area a and area B of a single flexible display device.

FIG. 12 is a diagrammatic representation of region A and region B for reference purposes.

Fig. 13 is a flow diagram of an embodiment of a method for rendering images on a flexible display device in an HMD.

Fig. 14 is a flow diagram of a different embodiment of a method for rendering images on a flexible display device in an HMD.

Fig. 15 is an exemplary embodiment of a flexible display device.

It should be understood that the drawings are for purposes of illustrating the concepts of the disclosure and are not necessarily the only possible configuration for illustrating the disclosure.

Detailed Description

This specification illustrates the principles of the disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the disclosure and are included within its spirit and scope.

All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the principles of the disclosure 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.

Moreover, all statements herein reciting principles, aspects, and embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, no structure whatsoever is intended to be implied by such equivalents including currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function.

Fig. 1a is an HMD 10 with a slot 101 for receiving a display device 11 a. The display device 11a has a substantially flat and rigid display. The display device 11a is, for example, a mobile communication apparatus such as a smartphone. Fig. 1b is the same HMD 10 seen from above when worn by a person 12. The display device 11a may be inserted into the slot 101 and is shown in an inserted position 11 b. Examples of similar HMDs are the Google Cardboard and Daydream models.

Fig. 2a is an HMD 20 according to an embodiment. The flexible display device 21a may be inserted into the slot 201. Fig. 2b is a top view of the same HMD 20 worn by person 12. The flexible display device 21a may be inserted into the slot 201 and is shown in an inserted position 21 b. The flexible display device 21a is, for example, a flexible mobile communication device such as a smartphone. According to embodiments, instead of having slots 201 on one side thereof, HMD 20 may have slots on each side, and/or slots on the top or bottom thereof. According to embodiments, HMD 20 may not have a slot, in which case flexible display device 21a may be attached to HMD 20, HMD 20 having an opening or receptacle for receiving flexible display device 21 a. As can be observed in fig. 2b, the flexible display device 21a is constrained to take a curved form when in the inserted position 21 b. As will be discussed further, this curved form helps to improve the user experience of the images displayed in the peripheral FOV of user 12.

Fig. 3 a-3 c are embodiments in which an HMD receives a single flexible display 30, which flexible display 30 may take a curved (e.g., concave) form as shown in fig. 3 a/3 b once inserted into an HMD according to an embodiment. The display area of the display 30 may be divided into a plurality of areas, i.e., a display area a 301 and a display area B302, as shown. Region B302 may be a region defined by a curved display region in the peripheral FOV, while region a 301 may be defined as a (substantially) non-curved or ((substantially) flat) display region not in the peripheral FOV. Further definitions of region a and region B can be found in fig. 12a and 12B.

Fig. 4 a/4 b are embodiments in which the HMD 40 is configured to receive two flexible display devices 41a and 42 a. Fig. 4b is the same HMD 40 as seen from above when worn by the user 12. The flexible displays 41a and 42a are shown in their respective inserted positions 41b and 42 b.

Fig. 5 a-5 c illustrate the use of multiple flexible displays, such as in the HMD 40 of fig. 4 a/4 b, and in particular the definition of the display area in such embodiments. Once inserted into the HMD 40, each of the two flexible displays 41a and 42a may take the curved (e.g., concave) form of fig. 5 b. A region a501 and a region B502 are defined in the display area of each flexible display 41a and 42a, wherein region a501 is defined as a (substantially) non-curved/flat region that is not in the peripheral FOV of the user 12, and region B502 is defined as a (substantially) curved region that is in the peripheral FOV of the user 12.

Fig. 6a and 6b show an embodiment in which a single flexible display 61a is used and, once inserted into the HMD 60, constrained by the HMD 60 to take a doubly curved (e.g., concave) form 61 b.

Fig. 7a to 7c show how the areas a and B are defined in the display area of a single flexible display 61 a. The display area of the single flexible display 61a is divided into two image areas, one area for each eye; a left-eye image area 70a and a right-eye image area 70 b. Each of the two image areas has its own area a and area B; the region a701a and the region B701B are for the image region 70a, and the region a702a and the region B702B are for the image region 70B.

In fig. 3c, respectively 5c, respectively 7c, the area a 301, respectively a 501, respectively a701 a/702a are depicted as rectangles with an angle of 90 degrees. According to an embodiment, the area a 301, respectively the area a 501, respectively the area a701 a/702a may be rectangular(s) with rounded edges. According to an embodiment, the area a 301, respectively the area a 501, respectively the area a701 a/702a may have another form, for example an elliptical form. The area B302, respectively the area B502, respectively the area B701B/702B may follow the contour of the area A301, respectively the area A501, respectively the area A701 a/702 a.

According to an embodiment (not shown), the flexible display device(s) are inserted via slot(s) configured in the top or bottom of the HMD. According to an embodiment (not shown), the one or more flexible display devices, once inserted into the HMD, may be bent into, for example, one of the previous forms. According to embodiments (not shown), the HMD may thus force (constrain) the flexible display device(s) to take a desired form after insertion into the one or more slots, for example, by spring-actuated levers mounted on the HMD that, when operated by a user, apply mechanical pressure to a mold or pad configured to bend the flexible display(s) into the desired form.

As previously indicated, image region B surrounds region a, and the image to be displayed in region B may not require as much detail as the image displayed in region a, since region B corresponds to a peripheral FOV area where the human eye cannot observe detailed information. However, since the human eye is highly sensitive to common details (movement) in its peripheral FOV, image region B may include common details. Thus, the image processing characteristics of regions a and B may be different, as will be discussed further below. For example, region a remains unchanged in terms of processing or an undistorted algorithm is applied to region a (image processing characteristics are the application of undistorted algorithms), while region B is smoothed (image processing characteristics are the application of smoothing), typically using gaussian, median or average filtering (image processing characteristics are the application of filtering). The incremental smoothing of region B or even the ordinary smoothing may be applied to the edges of the image; for example weighted by the distance between the border between area a and area B and the image edge, or no smoothing at the border between area a and area B, but ordinary smoothing near the edge of area B/near the image edge. The strength of the filter may be a function of the distance in region B, for example: at the beginning of region B (i.e., position (0, y) of the image, y > yA, where yA is the beginning of region a according to the vertical axis, raster scan), the filtering strength is high or at a maximum, and at the end of region B (i.e., position (xA, y), where xA is the beginning of region a), the filtering strength is low or at a minimum. For example, the area B of the original image is replaced with an image extension in the boundary of the area a (the image processing feature is pixel replacement/pixel extension), for example, the pixels outside the boundary of the area a take the value closest to the boundary pixel, or the area B is a mirror image of the area a (the image processing feature is mirror image).

Fig. 8 a/8 b illustrate a particular embodiment of (different, distinct) image processing differentiated according to display area. In fig. 8a, an image 80 has a perimeter defined by an image height 81 and an image width 82. Inside the perimeter of the image 80, a focal region 80a having a height 83 and a width 84 may be defined. The region outside the focal region is, for example, a region in the peripheral FOV and is indicated by reference numeral 80 b. The portion of the image 80 that is in the focal region 80a may be processed differently than the portion that is outside the focal region (80 b). Fig. 8b is an example result of such a different process. In 86a, an image of a 3D cube is shown. In 86b, the image is shown with the perimeter 85 of the focal region. The images in the focal zone 80a are processed at a high level of detail (high spatial and/or temporal resolution, high bit rate), while the images outside the focal zone (80b) are processed at a low (lower) level of detail (low (lower) spatial and/or temporal resolution, low (lower) bit rate). The resulting image is indicated by reference numeral 86 c. According to an embodiment, the focus area 80a corresponds to area a and 80B corresponds to area B of the aforementioned flexible display device.

Fig. 9 a/9 b illustrate another particular embodiment of image processing according to region differentiation. In fig. 9a, the image 90 to be displayed is defined by an image height 91 and an image width 92. While the image region of the image may be defined as indicated by reference numeral 90b, outside the perimeter (periphery) of the image 90, the region 90a may be defined as having a height 93 and a width 94; this region will be further referred to as extension region 90 a. In fig. 9b, reference numeral 96a is an image of the 3D cube with its shadow, the shadow being drawn with the periphery of the image expansion area 90a, and the periphery of the image expansion area 90a being indicated by a dotted line. Reference numeral 96b gives a simple example of how the outer part of the image 90 (the part of the image that is located in the peripheral region of the image) is used to calculate the image of the image expansion area 90 a. Reference numeral 96c depicts the resulting image. According to an embodiment, the image area 90B corresponds to the area a of the aforementioned flexible display device, and the extension area 90a corresponds to the area B. According to an embodiment, the image of the area B is calculated from the image to be displayed in the area a based on data extracted from the outer area of the image to be displayed in the area a.

Fig. 10a illustrates visual distortion of an image displayed on a flexible display device, the visual distortion being observable by a user of an HMD equipped with one or more lenses (e.g., one lens per eye, or several lenses per eye). Reference numeral 100a is a displayed image. Reference numeral 101 is a lens. Reference numeral 102a is a distorted image observed by the user through the lens 101. The distortion shown corresponds to pincushion distortion. Other distortions may be caused by the lens (es) of the HMD, and distortions may be cumulative.

Fig. 10b illustrates how the distortion of fig. 10a may be corrected. The image 100b is deformed by applying a so-called warping translation during image processing. The warping transform corresponds to an inversion of the distortion and reduces or eliminates the distortion caused by the lens 101. Here, a pincushion distortion 102a is illustrated, the inverse of which is a barrel distortion 100 b. The resulting image 102b observed by the user is corrected. The parameters of the warping transformation to be applied to the image by image processing depend on the characteristics (characteristics, parameters, properties) of the lens (es) used. According to an embodiment, the image processing for the warp transform is applied only to the part of the image/image to be rendered in region a, and therefore not to region B, since region B corresponds to the peripheral FOV of the user, as described above, where detailed information cannot be resolved by the human eye. This advantageously reduces the image processing effort required to render the image/part of the image to be rendered in region B. For example, the distortion correction may be implemented using a Brown-Conrady model, which is not further explained here. Other types of correction, such as chromatic aberration correction, may also be applied to further improve the image quality. Typical lens characteristics (characteristics, parameters, attributes) that may help define image processing steps that can correct for image distortion caused by the lens (es) are the lens field of view, which is used by the 3D renderer to set the virtual camera FOV; a parameter defining pincushion distortion or a parameter defining a corresponding barrel distortion image processing operation for correcting pincushion distortion; r, G and B channel coefficients for color difference correction. Other shot characteristics may help define other image processing steps to further improve image quality.

According to an embodiment, the HMD is associated with a Quick Response (QR) code that, when read by a QR code reader application in the flexible display device(s) that will use (be inserted into) the HMD, enables the flexible display device(s) to obtain characteristics (features, parameters, attributes) of the HMD, which will enable the flexible display device(s) to define and configure image processing features that facilitate rendering images on the flexible display device(s) in the HMD. For example, HMD characteristics may be specified in terms of lens characteristics, in terms of flexible display curvature, and in terms of the size of regions a and B. According to an embodiment, such a QR code is associated with (e.g., printed, imprinted on) the HMD. According to an embodiment, the QR code may be obtained from the webpage based on, for example, HMD selection or HMD type/model in the HMD list. According to an embodiment, the characteristics may comprise a plurality of sets of characteristics, wherein each set of characteristics is associated with a particular flexible display device. For example, the same HMD may be capable of receiving flexible display devices in multiple formats (e.g., 4 inches to 5.5 inches). For example, the same HMD may receive a flexible display 21a that, upon insertion into the HMD, would be constrained to take the form 21b of fig. 3b, or, if the flexible display has a larger format, the form 61a of fig. 7 b. For example, the same HMD may receive one flexible display device (fig. 2-3 and 6-7), or two flexible display devices (fig. 4-5). The same HMD may receive one flexible display device in a landscape orientation, or two flexible display devices in landscape or portrait orientations. Thus, the image processing features of the flexible display device(s) to be used with the HMD may depend on the characteristics of the HMD, the type of flexible display device(s) used, whether one or two flexible display devices are used, and the orientation of the flexible display devices. Although the display device itself may detect the lateral or longitudinal direction of the display device, automatically displaying the direction is inconvenient because head movement causes undesirable effects when the display device is used with an HMD.

According to embodiments, the HMD may communicate its characteristics to the flexible display device(s) that will use the HMD via wireless transmission, such as Wi-Fi, bluetooth, or Near Field Communication (NFC). For example, the flexible display device may read the characteristics by reading an NFC tag incorporated in the HMD. According to embodiments, the HMD user may specify the manner how the HMD is to be used (flexible display/s, flexible display orientation) and the flexible display device(s) may determine the size of regions a and B, and which image processing features to apply to the images displayed in each region, based on these information sources.

According to embodiments, the characteristics of the areas a and B, such as size and x-y position, may be user (wearer) definable or user (wearer) adjustable. According to an embodiment, regions a and B may be centered according to the HMD wearer's interpupillary distance (IPD or PD of interpupillary distance). The IPD is a wearer-specific parameter that can be measured by sensor elements that can help measure parameters such as displacement, distance, position (e.g., camera) in the flexible display device before or after inserting the flexible display device into the flexible display device. Alternatively, the IPD may be determined by the HMD based on, for example, measurements of the head circumference, which may be obtained by the HMD measuring the head band length when the HMD is automatically adjusted or the wearer is manually adjusted, or from measured tear strengths applied to the headband support(s) of the HMD, such as when the headband is of a universal type. Alternatively, the IPD may be preconfigured based on, for example, the HMD wearer's age specified by the HMD wearer; for example, if the wearer is an adult, the IPD may be set to 6.3 cm, and if the wearer is a child, the IPD may be set to 5.1 cm.

According to an embodiment, the characteristics of the areas a and B may also be adjusted according to the eye-to-display distance. The eye-to-display distance may be a parameter specific to each HMD. Pre-configuration may include obtaining the wearer-specific parameters described above, obtaining HMD parameters, obtaining a configuration of use of the HMD (e.g., one display, two displays, portrait or landscape display orientation), and obtaining parameters of the flexible display device(s) used with the HMD (e.g., screen size, number of pixels). The pre-configuration may determine the size and location of the regions a and B, as well as the different image processing characteristics associated with each of these regions.

Fig. 11 is a diagrammatic representation illustrating the determination of areas a and B of a single flexible display device. A and B may be defined from, for example, the following characteristics (parameters, attributes):

-f, representing the focal length of a lens system in the HMD;

-d_IPDreference numeral 1108, which denotes the interpupillary distance (in centimeters) of the user;

-d_ETS1103, indicating the eye-to-display distance (in centimeters) of the HMD;

-d_STLreference numeral 1102, which denotes the display-to-lens distance (in centimeters) of the HMD;

-w_Areference numeral 1121, which denotes the pixel width of the area a of the flexible display device used;

α, reference numeral 1105, represents the angle between the coronal plane of the head (i.e., the plane defined from ear to ear) and the boundary of the user's eye external vision (i.e., the outer limits of binocular vision). Typically, this angle is 62 °, i.e. about pi/3, and can be considered as a fixed value, whereas if the image displayed in the HMD is responsive to head movement (i.e. causing a translation according to head movement), this angle can be adjusted to 30 ° or 20 °, which corresponds to the limits of the eye identifier or color;

ppcm, representing the pixel density per centimeter (RGB triplet) of the flexible display device used. Generally, 150-.

Assuming that the flexible display device is centered on the HMD, i.e. the HMD center is aligned with the display center, and assuming that horizontal plane binocular vision is generally possible in the range of-62 ° to +62 °, where 0 ° is the direct-view direction (perpendicular to the ear-to-ear plane):

w_A＝(2.tan(α).d_ETS+d_IPD)/(f/f-d_STL))*ppcm

for example, consider α as 62 °, d_ETS＝2cm，d_STL＝0.5cm，ppcm＝150，f＝3.5cm→w_A(the pixel width of the region a) is 1000 pixels. With the pixel width of the region a 1121 known, the pixel width of the region B1120 can be calculated as the pixel width/4 of the flexible display. In the above example, only the width is calculated. For the calculation of height, a preservation of the aspect ratio of the processed image can be used to determine it, where:

Aspect ratio tan (vertical FOV/2)/tan (horizontal FOV/2)

Wherein the horizontal FOV/2 is alpha and the width is w_AAnd an aspect ratio generally equal to 16/9 or 3/4; the aspect ratio may be retrieved from the image or display characteristics.

Alternatively, the height of region a is equal to the height of the processed image (i.e., so the thickness of the "frame members" 120a, 120B (see fig. 12) of region B may be zero).

When the surface of the region B is not simply rectangular and is, for example, in the form of an ellipse, w_ADefining the width of the ellipse on its major axis.

FIG. 12 is a diagrammatic representation of regions A and B for reference purposes. The display area of the flexible display device may be defined by an outer rectangle. In fig. 12a, the area a121 is an inner rectangle, and the area B120 may be represented as a frame surrounding the area a 121. The "frame" of region B has an upper member 120a, a lower member 120B, a left member 120c, and a right member 120 d. The upper, lower, left and right members may have the same, different or variable thicknesses. The thickness of the frame member may be zero at least at some points of the frame member. In fig. 12a, the areas a and B are represented as rectangles in two longitudinal directions. However, the areas a and B may have a transverse direction and the directions of the areas a and B may be different, e.g. the area a may have a transverse direction and the area B a longitudinal direction, or vice versa. The areas a and B may not be rectangular in form but for example have at least partially a circular form in the form of an ellipse, and the areas a and B may combine any of these forms, for example, although the area B is a frame having an outer rectangular form, if the area B is at least partially an elliptical form such as shown for example in fig. 12B, its inner form may be at least partially elliptical.

Fig. 13 is a flow diagram 1300 of an embodiment of a method for rendering images on at least one flexible display device in a head mounted device.

In a first step 1301, image processing features of an image to be rendered on the at least one flexible display device are configured in accordance with a first display area of the at least one flexible display device on which the image is to be rendered and a second display area of the at least one flexible display device on which the image is to be rendered, the second display area surrounding the first display area and the first display area corresponding to the focus field of view and the second display area corresponding to the peripheral field of view. Example image processing features are processing using high or low spatial and/or temporal resolution, smoothing, applying filtering, pixel replacement, copying, image expansion.

In step 1302, at least one flexible display device, once inserted into the head mounted device, renders an image on a first display area and a second display area of the at least one flexible display device according to configured image processing features. The image may be a frame of a video sequence.

Fig. 14 is a flow diagram 1400 of a different embodiment of a method for rendering images on at least one flexible display device in a head mounted device.

In a first step 1401, properties of the HMD are obtained from the HMD. For example, these properties may include characteristics related to the lens used in the HMD, such as focal length (length), lens distortion, chromatic aberration, lens FOV, and interpupillary distance (if measured by the HMD), display-to-lens distance, eye-to-display distance, possible lateral/longitudinal directions of the flexible display device when inserted into the HMD, curvature of the flexible display device when inserted into the HMD.

In step 1402, based on the attributes obtained in step 1301, a first display area (e.g., area a) and a second display area (e.g., area B) are determined for rendering an image on the flexible display device. The second display area surrounds the first display area (e.g., area B may be viewed as a frame around area a), and the first display area corresponds to the focal field of view of the human eye and the second display area corresponds to the peripheral field of view of the human eye.

In step 1403, image processing features of the image to be rendered on the flexible display are configured according to the display area (e.g., area a or B) in which the image is to be rendered. Example image processing features are processing with high or low spatial and/or temporal resolution, smoothing, applying filtering, pixel replacement, copying, image expansion

In step 1404, an image is rendered on the first display area and the second display area of the at least one flexible display device upon insertion of the at least one flexible display device into the head mounted device according to the configured image processing features. The image may be a frame of a video sequence.

Fig. 15 is an exemplary embodiment of a flexible display device. The display device 1500 includes at least one processor 1501 configured to perform the steps shown in fig. 13. The flexible display device may also include a memory 1502, which may be configured to store data such as images before and after image processing, image processing feature configuration settings, properties of the HMD, definitions of regions a and B, and instructions executable by the processor 1501. The one or more network interfaces 1503 may be configured to interface with a wireless network 1510 such as 3G-5G/NR, NFC, bluetooth, or WiFi, and may be configured to read attributes of the HMD, configured to connect to other devices, to a LAN, a WAN, or to the internet, for example. One or more peripherals 1504 may be configured to read the HMD's quick response code, in which case the peripherals include sensors, such as camera devices. Display/input 1505 may be configured to render images and receive user input.

It should be understood that some of the elements in the figures may not be used or necessary in all embodiments. Some operations may be performed in parallel. Embodiments other than those illustrated and/or described are possible. For example, a device implementing the present principles may include a mix of hardware and software.

It should be appreciated that aspects of the principles of the present disclosure may be embodied as a system, method, or computer-readable medium. Accordingly, aspects of the present principles may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining hardware and software aspects that may all generally be defined herein as a "circuit," module "or" system. Furthermore, aspects of the principles of the present disclosure may take the form of a computer-readable storage medium. Any combination of one or more computer-readable storage media may be utilized.

Thus, for example, it should be understood that the diagrams presented herein represent conceptual views of illustrative system components and/or circuitry embodying the principles of the disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudocode, and the like represent various processes which may be substantially represented in computer readable storage media and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

The computer-readable storage medium may take the form of a computer-readable program product embodied in one or more computer-readable media and having computer-readable program code embodied thereon that is executable by a computer. Computer-readable storage media, as used herein, is considered to be non-transitory storage media in view of the inherent ability to store information therein and the inherent ability to provide retrieval of information therefrom. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Some or all aspects of the storage medium may be located remotely (e.g., in the "cloud"). It is to be understood that the following, while providing more specific examples of computer readable storage media to which the present principles may be applied, are merely illustrative and non-exhaustive lists (as readily understood by one of ordinary skill in the art): a hard disk, a Read Only Memory (ROM), an erasable programmable read only memory (EPROM or flash memory), a portable compact disc read only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.