Information processing apparatus, method of controlling the same, and storage medium

Abstract

To provide an information processing device, a control method thereof, and a program capable of reducing a difference between a visual sense and a bodily sensation of a user even under a situation of riding on a vehicle, and preventing a sense of immersion in display by XR technology from being lowered.SOLUTION: The XR system 100 includes a moving object coordinate system-self-position acquisition unit 600 that acquires position information in a moving object coordinate system 300, a world coordinate system-self-position conversion unit 603 that acquires position information in a world coordinate system 301, a first rendering unit 607 and a second rendering unit 609 that render a plurality of CG objects in accordance with the position information of each coordinate system, a combining processing unit 611 that combines images that are rendering results of the plurality of CG objects by the first rendering unit 607 and the second rendering unit 609, and a display processing unit 613 that displays an image combined by the combining processing unit 611.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an information processing device, a control method thereof, and a program, and more particularly to an information processing device, a control method thereof, and a program that draws an image based on a plurality of pieces of position information. [Background technology]

[0002] In recent years, VR technology, which uses information processing devices such as head-mounted displays to allow users to visually perceive themselves as existing in a virtual space, and AR / MR technology, which overlays virtual objects on real-world objects, have begun to be put into practical use. These technologies are collectively known as XR technology.

[0003] Among these, there is a problem that when XR technology is used in situations such as when riding in a vehicle such as a car or an airplane, the accuracy of estimating the user's own position and orientation decreases.To solve this problem, Patent Document 1 changes which of the image information obtained from an imaging device and the inertial information obtained from an inertial sensor is more reliably used depending on the situation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7147775 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the technology of Patent Document 1, even when the user is riding in a vehicle, the user's movement status, including the movement of the vehicle itself, is not reflected on the display of the information processing device, and the display may appear as if no movement is occurring. In this case, the user experiences the acceleration (G) caused by the movement of the vehicle, but cannot visually confirm the movement, which causes nausea and reduces the sense of immersion in the display provided by XR technology.

[0006] The present invention provides an information processing device, a control method thereof, and a program that can reduce the difference between a user's vision and physical sensation even when riding in a vehicle, and prevent a decrease in the sense of immersion in the display provided by XR technology. [Means for solving the problem]

[0007] In order to solve the above problem, the present invention is characterized by having a position acquisition unit that acquires position information in two or more coordinate systems, a drawing unit that draws multiple CG objects according to the position information in the two or more coordinate systems, a synthesis processing unit that synthesizes an image that is the result of drawing the multiple CG objects by the drawing unit, and a display processing unit that displays the image synthesized by the synthesis processing unit. [Effects of the Invention]

[0008] Even in situations such as riding in a vehicle, the difference between the user's vision and physical sensation can be reduced, preventing a decrease in the sense of immersion in the display caused by XR technology. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing the hardware configuration of an XR system as an information processing device according to the present invention. [Figure 2] FIG. 1 is a diagram showing the position of a user using an XR system while on board a Shinkansen train. [Figure 3] FIG. 1 is a diagram for explaining two coordinate systems used by an XR system. [Figure 4] FIG. 10 is a diagram showing an example of the field of view when a user is using the XR system in augmented reality mode on a Shinkansen train. [Figure 5] FIG. 10 is a diagram showing an example of the field of view when a user is using the XR system in virtual reality mode on a Shinkansen train. [Figure 6] FIG. 2 is a block diagram showing the software configuration of the XR system according to the first embodiment. [Figure 7]FIG. 7 is a diagram showing an example of data held by the CG object data in FIG. 6 according to the first embodiment. [Figure 8] 7 is a diagram showing an example of data held by the CG instance data in FIG. 6 according to the first embodiment. FIG. [Figure 9] 7A to 7C are diagrams showing examples of a first rendering result, a second rendering result, and a combined rendering result in FIG. 6 according to the first embodiment. [Figure 10] 7 is a flowchart of a composited drawing result generation process executed by the composition processing unit in FIG. 6. [Figure 11] 10A to 10C are diagrams for explaining time-series changes in a composited drawing result in the first embodiment. [Figure 12] FIG. 10 is a diagram showing an example of data held by CG instance data according to the second embodiment. [Figure 13] 10A to 10C are diagrams for explaining time-series changes in a first rendering result, a second rendering result, and a combined rendering result in the second embodiment. [Figure 14] FIG. 11 is a block diagram showing the software configuration of an XR system according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The basic configuration of an information processing device according to the present invention will be described with reference to FIG.

[0011] FIG. 1 is a block diagram showing the hardware configuration of an XR system 100 as an information processing device according to the present invention.

[0012] The XR system 100 has a CPU 101, a ROM 102, a RAM 103, a communication IF (interface unit) 104, an imaging device 105, an inertial sensor 106, a GPU 107, and a display 108, and each of these components is connected by a bus 109.

[0013] The CPU 101 executes programs stored in the ROM 102 and programs loaded into the RAM 103, and controls the operation of the XR system 100. The ROM 102 is a read-only memory that stores a boot program, firmware, various processing programs for implementing the processes described below, and various data. The RAM 103 is a work memory that temporarily stores programs and data for processing by the CPU 101, and the various processing programs and data are loaded into the RAM 103 by the CPU 101.

[0014] The communication IF 104 is an interface for communicating with an external device via a network, and transmits and receives various data via the network.

[0015] The imaging device 105 is, for example, a camera, and captures a real-world image of the surroundings of the XR system 100.

[0016] The inertial sensor 106 includes a triaxial acceleration sensor that detects acceleration in three axial directions and an angular velocity sensor that detects angular velocity around the three axes. The inertial sensor 106 acquires the acquired acceleration in the three axial directions and angular velocity around the three axes as inertial information.

[0017] A GPU (Graphics Processing Unit) 107 performs image processing in accordance with a program stored in ROM 102 or a program loaded into RAM 103. The GPU 107 cooperates with the CPU 101 to realize the software functions of the XR system 100, and generates images such as a first rendering result 608, a second rendering result 610, and a composited rendering result 612, which will be described later.

[0018] Display 108 displays an image generated by CPU 101 or GPU 107 and presents it to the user. Display 108 is a head-mounted display, and may be a retinal projection type head display that projects the display on a display panel, or a retinal scanning type head-mounted display that directly draws an image on the retina.

[0019] The bus 109 connects various devices.

[0020] FIG. 2 is a diagram showing the position of a user 202 who uses the XR system 100 while on board a Shinkansen 200 (moving object).

[0021] A velocity vector 201a indicates the velocity of the Shinkansen 200 at time t.

[0022] Time t position 203 is the position of user 202 at time t.

[0023] A velocity vector 201b indicates the velocity of the Shinkansen 200 at time t+1.

[0024] Time t+1 position 204 is the position of user 202 at time t+1.

[0025] In this way, between time t and time t+1, the velocity of the Shinkansen 200 changes from velocity vector 201a to velocity vector 201b. A user 202 aboard the Shinkansen 200 experiences the movement of the Shinkansen 200 due to this change (acceleration (G)).

[0026] FIG. 3 is a diagram illustrating two coordinate systems used by the XR system 100.

[0027] The moving body coordinate system 300 is a coordinate system based on the Shinkansen 200 (moving body) carrying the user 202, and the coordinates of the user 202 based on the moving body coordinate system 300 are affected by the movement of the user 202.

[0028] The world coordinate system 301 is a coordinate system based on the Earth, and the coordinates of the user 202 based on the world coordinate system 301 are affected by the movement of the Shinkansen 200 and the movement of the user 202 .

[0029] In this embodiment, the XR system 100 uses two coordinate systems, the moving body coordinate system 300 and the world coordinate system 301, but two or more coordinate systems may be used.

[0030] FIG. 4 is a diagram showing an example of the field of view when a user 202 is using the XR system 100 in augmented reality (MR) mode on a Shinkansen train 200.

[0031] The interior of the Shinkansen train 400 and the scenery from the train window 401 are real images.

[0032] The virtual window 402 is a virtual object that is rendered as CG on the display 108 of the XR system 100 used by the user 202, and follows the moving body coordinate system 300.

[0033] FIG. 5 is a diagram showing an example of the field of view when a user 202 is using the XR system 100 in virtual reality (VR) mode on a Shinkansen train 200.

[0034] The virtual space of the vehicle interior 500 is an image rendered as CG on the display 108 of the XR system 100 used by the user 202, and follows the moving body coordinate system 300.

[0035] In this way, when only the virtual space of the vehicle interior 500 is displayed on the display 108, the image of the virtual space of the vehicle interior 500 remains still even when the user 202 experiences the acceleration (G) as shown in Fig. 2. As a result, the user feels a discrepancy between what they see and what they experience, and the sense of immersion in the virtual space of the vehicle interior 500 decreases.

[0036] In the following embodiment, the main configuration and processing procedures for preventing this decrease in immersion in the XR system 100 will be described.

[0037] <Embodiment 1> 6 is a block diagram showing a software configuration 6 of the XR system 100 in embodiment 1. The functions of the software configuration 6 are realized by the CPU 101 and GPU 107 working together.

[0038] In Figure 6, the software configuration 6 includes a mobile body coordinate system self-position acquisition unit 600, a mobile body movement information acquisition unit 602, a world coordinate system self-position conversion unit 603, a first drawing unit 607, a second drawing unit 609, a synthesis processing unit 611, and a display processing unit 613.

[0039] The mobile body coordinate system self-position acquisition unit 600 (position acquisition unit) acquires a mobile body coordinate system self-position 601, which is the self-position and orientation of the XR system 100 in the mobile body coordinate system 300. As described in Patent Document 1, the self-position may be acquired by changing the ratio of image information and inertial information acquired from the imaging device 105 and the inertial sensor 106, which is more reliably used, depending on the situation of the user 202.

[0040] The mobile object movement information acquisition unit 602 acquires movement information of a mobile object (here, Shinkansen 200). The acquired information may be the position of the mobile object in the world coordinate system 301, or the velocity vector or acceleration vector of the mobile object in the world coordinate system 301. The mobile object movement information acquisition unit 602 acquires the movement information of the mobile object by querying the mobile object. When velocity vector or acceleration vector information is acquired as the movement information of the mobile object, the mobile object movement information acquisition unit 602 calculates the position of the mobile object in the world coordinate system 301 by performing an integration process on the acquired information.

[0041] The world coordinate system self-position conversion unit 603 (position acquisition unit) acquires a world coordinate system self-position 604, which is the self-position and orientation of the XR system 100 in the world coordinate system 301, based on the moving body coordinate system self-position 601 and the movement information of the moving body acquired from the moving body movement information acquisition unit 602. Specifically, first, translation information (Tx, Ty, Tz) of the moving body is acquired from the moving body movement information acquisition unit 602, and based on this, a transformation matrix (MovToWldMat) shown in the following [Equation 1] is generated. Next, the coordinates (Mx, My, Mz) of the moving body coordinate system self-position 601 are converted into coordinates (Wx, Wy, Wz) of the world coordinate system self-position 604 using this transformation matrix.

[0042]

number

[0043] The CG object data 605 stores information about the CG objects to be rendered by the first rendering unit 607 and the second rendering unit 609 .

[0044] The CG instance data 606 stores a CG instance consisting of the position and coordinate system information of a CG object drawn by the first drawing unit 607 and the second drawing unit 609 for each application selectable in the virtual reality mode.

[0045] A first rendering unit 607 (rendering unit) generates an image that is a first rendering result 608 by rendering target CG object data 605 at the moving body coordinate system self-position 601. Here, the vehicle interior 500 (FIG. 5) in the virtual space is displayed as the first rendering result 608.

[0046] A second rendering unit 609 (rendering unit) generates an image as a second rendering result 610 by rendering the target CG object data 605 at the world coordinate system self-position 604 .

[0047] The composition processing unit 611 generates a composed image 612 by combining the image of the first rendering result 608 and the image of the second rendering result 610 .

[0048] A display processing unit 613 displays the image, which is the composite drawing result 612, on the display .

[0049] FIG. 7 is a diagram showing an example of data held by the CG object data 605 in this embodiment.

[0050] The CG object ID 700 holds information that uniquely identifies a CG object.

[0051] The CG object name 701 holds the name of the CG object.

[0052] The object data 702 holds information about the CG object to be drawn.

[0053] FIG. 8 is a diagram showing an example of data held by the CG instance data 606 in this embodiment.

[0054] The CG instance ID 800 holds information that uniquely identifies a CG instance.

[0055] The CG object ID 801 holds the ID of the CG object drawn by the target CG instance among the CG objects in FIG.

[0056] The rendering coordinate system 802 holds information indicating whether the target CG instance is rendered using a position calculated in the world coordinate system 301 or the moving body coordinate system 300. In other words, each of the CG objects in FIG. 7 is linked to either the world coordinate system 301 or the moving body coordinate system 300.

[0057] The CG instance position information 803 holds position information at which the target CG instance is placed in the rendering coordinate system 802. Although not shown in Fig. 8, the CG instance position information 803 may also hold orientation information that indicates the orientation in which the target CG instance is placed.

[0058] FIG. 9 is a diagram showing an example of a first rendering result 608, a second rendering result 610, and a combined rendering result 612 in this embodiment.

[0059] The first rendering result 608 and the second rendering result 610 hold color information and depth information for each pixel.

[0060] The combined rendering result 612 is the result of combining the first rendering result 608 and the second rendering result 610 .

[0061] FIG. 10 is a flowchart of the composited drawing result generation process executed by the composition processing unit 611.

[0062] In step S1000, it is determined whether all pixels in the drawing result have been scanned. If there are unscanned positions (YES in step S1000), the process proceeds to step S1001. If there are no unscanned positions (NO in step S1000), the process ends.

[0063] In step S1001, one position extracted from the group of unscanned positions is set as a comparison position (x, y).

[0064] In step S1002, it is determined whether the first rendering result depth at the comparison position (x, y) is smaller than the second rendering result depth. If the first rendering result depth is smaller (YES in step S1002), the process proceeds to step S1003; if not (NO in step S1002), the process proceeds to step S1004.

[0065] In step S1003, the first rendering result (x, y) is substituted for the combined rendering result (x, y), and the process returns to step S1000.

[0066] In step S1004, the second rendering result (x, y) is substituted for the combined rendering result (x, y), and the process returns to step S1000.

[0067] FIG. 11 is a diagram for explaining the time series changes in the composited drawing result 612 in this embodiment.

[0068] The composited drawing result 612 is drawn on the display 108 when a user 202 aboard the Shinkansen 200 uses the XR system 100 in virtual reality mode. A second drawing result 610 included in the composited drawing result 612 changes according to a world coordinate system self-position 604. A first drawing result 608 included in the composited drawing result 612 is the same as the train interior 500 in the virtual space of FIG. 5, and changes according to a moving object coordinate system self-position 601.

[0069] For example, between time t and time t+1 shown in Figure 2, the CG instance of the second drawing result 610 moves from the drawing position 1100 at time t to the drawing position 1101 at time t+1, but the CG instance of the first drawing result 608 does not move because it is displayed in the moving body coordinate system 300.

[0070] As described above, according to this embodiment, by changing the second drawing result 610 drawn on the display 108 in accordance with the world coordinate system self-position 604, it is possible to visually convey to the user 202 the movement information of the Shinkansen 200, which is a moving body. As a result, it is possible to reduce the difference between what the user 202 sees and what they experience, and it is possible to prevent a decrease in the sense of immersion in the virtual space of the train interior 500.

[0071] <Embodiment 2> In the first embodiment, a method for realizing the functions of the software configuration 6 that holds the drawing coordinate system 802 that indicates whether each piece of CG instance data 606 is drawn in the moving body coordinate system or the world coordinate system was described. On the other hand, in the second embodiment, a method for realizing the functions of the software configuration 6 in the case where no CG objects drawn in the world coordinate system are registered in any of the applications selectable in the virtual reality mode.

[0072] In the following description of this embodiment, the same components as those in the first embodiment will be denoted by the same reference numerals.

[0073] FIG. 12 is a diagram showing an example of data held by the CG instance data 606 in this embodiment.

[0074] The CG instance ID 800 holds information that uniquely identifies a CG instance.

[0075] The drawing CG object ID 801 holds the ID of the CG object that the target CG instance draws.

[0076] The CG instance position information 803 holds position information where the target CG instance is placed in the moving body coordinate system. Note that the CG instance position information 803 may also hold orientation information of the target CG instance.

[0077] In the second embodiment, the first rendering unit 607 handles all of the CG instance data 606 (second CG objects) stored for each application selectable in the virtual reality mode as rendering targets. On the other hand, the second rendering unit 609 handles a CG object (first CG object) that is application-independent and registered as an initial setting in the CG object data 605, in this case a spherical object 1300 shown in FIG. 13, as rendering targets.

[0078] FIG. 13 is a diagram for explaining time-series changes in a first rendering result 608, a second rendering result 610, and a combined rendering result 612 in this embodiment.

[0079] The spherical object 1300 is rendered in the second rendering result 610. The spherical object 1300 is an application-independent CG object that is registered in the CG object data 605 as an initial setting.

[0080] A first rendering result 608 is the result of rendering the CG instance data 606 to be rendered.

[0081] The combined rendering result 612 is the result of combining the first rendering result 608 and the second rendering result 610, and the spherical object 1300 that is the second rendering result 610 changes according to the self-position 604 in the world coordinate system.

[0082] As described above, according to this embodiment, no CG object for world coordinate system self-position 604 is registered in any of the applications, but spherical object 1300, which is CG data in the initial settings, is changed according to world coordinate system self-position 604. As a result, by visually conveying movement information about Shinkansen 200, which is a moving object, to user 202, the difference between what the user sees and what the user feels is reduced, and a decrease in the sense of immersion in the system is prevented.

[0083] <Embodiment 3> In the first and second embodiments, a case has been described in which the movement information of a moving body can be acquired from the Shinkansen 200 itself, which is a moving body, by the moving body movement information acquisition unit 602. In the third embodiment, a method for acquiring the movement information of a moving body when the moving body movement information acquisition unit 602 does not exist will be described.

[0084] In the following description of this embodiment, the same components as those in the first embodiment will be denoted by the same reference numerals.

[0085] Figure 14 is a block diagram showing the software configuration 14 of the XR system 100 in this embodiment. Only the differences from Figure 6 will be explained below. The functions of the software configuration 14 are realized by the CPU 101 and GPU 107 working together, similar to the software configuration 6 (Figure 6).

[0086] The world coordinate system self-position acquisition unit 1400 calculates the world coordinate system self-position 604, which is the self-position and orientation of the XR system 100 in the world coordinate system 301. For example, using the image information and inertial information acquired from the imaging device 105 and the inertial sensor 106, the range that matches the moving speed obtained from the inertial information is regarded as other than the moving body, and the self-position is calculated using the other image areas.

[0087] As described above, according to this embodiment, even if the mobile object movement information acquisition unit 602 does not exist, the world coordinate system self-position 604 can be calculated based on the information obtained from the imaging device 105 and the inertial sensor 106.

[0088] <Other embodiments> The present invention can also be realized by a process in which a program that realizes one or more functions of each embodiment is supplied to a system or device via a network or a storage medium, and one or more general-purpose processors ASICs in the computer of the system or device read and execute the program. The present invention can also be realized by a dedicated processor (e.g., an ASIC or FPGA) that realizes one or more functions. Furthermore, the present invention can also be realized by a combination of a general-purpose processor and a dedicated processor. Note that the term "processor" used here refers to a processor in a broad sense and includes both general-purpose processors and dedicated processors. The process that realizes the present invention may be performed by a single processor alone, or may be performed by multiple processors located in physically separate locations in cooperation with each other.

[0089] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

[0090] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention.

[0091] The disclosure of this embodiment includes the following configuration, method, and program. (Configuration 1) An information processing device characterized by having a position acquisition unit that acquires position information in two or more coordinate systems, a drawing unit that draws multiple CG objects according to the position information in the two or more coordinate systems, a synthesis processing unit that synthesizes an image that is the drawing result of the multiple CG objects by the drawing unit, and a display processing unit that displays the image synthesized by the synthesis processing unit. (Configuration 2) The information processing device according to configuration 1, wherein the two or more coordinate systems include a moving body coordinate system based on a moving body that carries a user of the information processing device. (Configuration 3) The information processing device according to Configuration 2, wherein the two or more coordinate systems include a world coordinate system based on the earth. (Configuration 4) An information processing device according to Configuration 3, further comprising an imaging device for acquiring image information of a surrounding real image and an inertial sensor for acquiring inertial information, wherein the position acquisition unit calculates position information in the moving body coordinate system based on the image information and the inertial information. (Configuration 5) The information processing device according to Configuration 3, further comprising a mobile body movement information acquisition unit that acquires movement information from the mobile body, wherein the position acquisition unit calculates position information in the world coordinate system based on the movement information of the mobile body and position information in the mobile body coordinate system. (Configuration 6) The information processing device according to Configuration 4, wherein the position acquisition unit calculates position information in the world coordinate system based on the image information and the inertial information. (Configuration 7) An information processing device described in any one of configurations 3 to 6, characterized in that the multiple CG objects include a first CG object and a second CG object, and the drawing unit draws the first CG object according to position information in the world coordinate system and draws the second CG object according to position information in the moving body coordinate system. (Configuration 8) The information processing device according to configuration 7, wherein the first CG object is a CG object independent of an application, and the second CG object is a CG object set for each application. (Method 1) A control method for an information processing device, comprising: a position acquisition step for acquiring position information in two or more coordinate systems; a drawing step for drawing multiple CG objects according to the position information in the two or more coordinate systems; a synthesis processing step for synthesizing an image resulting from the drawing of the multiple CG objects in the drawing step; and a display processing step for displaying the image synthesized by the synthesis processing step. (Program 1) A program for causing a computer to function as each means of the information processing device described in any one of configurations 1 to 8. [Explanation of symbols]

[0092] 105 Imaging device 106 Inertial Sensor 108 Display 300 Moving Body Coordinate System 301 World Coordinate System 600 Mobile body coordinate system self-position acquisition unit 602 Mobile object movement information acquisition unit 603 World coordinate system self-position transformation unit 607 First drawing section 609 Second drawing section 611 Synthesis Processing Unit 613 Display processing unit

Claims

1. a position acquisition unit that acquires position information in two or more coordinate systems; a drawing unit that draws a plurality of CG objects according to position information in the two or more coordinate systems; a synthesis processing unit that synthesizes an image resulting from the rendering of the plurality of CG objects by the rendering unit; a display processing unit that displays the image synthesized by the synthesis processing unit; An information processing device comprising:

2. 2. The information processing apparatus according to claim 1, wherein the two or more coordinate systems include a moving body coordinate system based on a moving body that carries a user of the information processing apparatus.

3. 3. The information processing apparatus according to claim 2, wherein the two or more coordinate systems include a world coordinate system based on the earth.

4. an imaging device for acquiring image information of a surrounding real image; an inertial sensor that acquires inertial information; 4. The information processing apparatus according to claim 3, wherein the position acquisition unit calculates position information in the moving body coordinate system based on the image information and the inertial information.

5. Further comprising a mobile object movement information acquisition unit that acquires movement information from the mobile object, 4. The information processing apparatus according to claim 3, wherein the position acquisition unit calculates the position information in the world coordinate system based on the movement information of the mobile object and the position information in the mobile object coordinate system.

6. The information processing apparatus according to claim 4 , wherein the position acquisition unit calculates position information in the world coordinate system based on the image information and the inertial information.

7. the plurality of CG objects include a first CG object and a second CG object; 4. The information processing apparatus according to claim 3, wherein the drawing unit draws the first CG object in accordance with the position information in the world coordinate system, and draws the second CG object in accordance with the position information in the moving body coordinate system.

8. 8. The information processing apparatus according to claim 7, wherein the first CG object is a CG object that does not depend on an application, and the second CG object is a CG object that is set for each application.

9. A control method for an information processing device, comprising: a position acquisition step of acquiring position information in two or more coordinate systems; a drawing step of drawing a plurality of CG objects according to position information of the two or more coordinate systems; a compositing step of compositing an image resulting from the rendering of the plurality of CG objects in the rendering step; a display processing step for displaying the image synthesized by the synthesis processing step; A control method comprising:

10. A program for causing a computer to function as each of the means of the information processing device according to claim 1.

Images