Control method and projection device

Abstract

The time until the geometric correction is completed is shorter than that in the related art.SOLUTION: A control method of a projection device 10 that projects an image on a projection surface includes determining, on the basis of an output from a first sensor 150, that a motion of the projection device 10 has stopped when a state in which a parameter value indicating the motion is smaller than a first threshold continues for a first period, detecting, in at least a part of the first period, at least one depth map indicating a distance from the second sensor 160 to each of a plurality of positions on the projection surface on the basis of an output from the second sensor 160, specifying, on the basis of the at least one depth map, a direction of the projection device 10 with respect to the projection surface, and correcting, on the basis of the specified direction, distortion of the image when it is determined that the motion has stopped.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control method and a projection device. [Background technology]

[0002] The projector according to Patent Document 1 includes a detection unit that detects and notifies the halt of movement of the projector body, and a trapezoidal distortion correction unit that, when the detection unit notifies the halt of movement of the projector body, starts trapezoidal distortion correction processing according to the relative positional relationship between the projector after movement and the projection surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-295321 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, measurement of information required for geometric correction such as trapezoidal distortion correction is not started until the conditions that trigger geometric correction are met, which results in a long time until the geometric correction is completed. Note that detecting that the movement of the projector body has stopped, i.e., that the projector is in a stationary state, is one example of a condition that triggers geometric correction. [Means for solving the problem]

[0005] A control method according to a first aspect of the present invention is a control method for a projection device that projects an image onto a projection surface, and includes: determining that the movement has stopped when a parameter value indicating the movement of the projection device remains less than a first threshold value for a first period based on output from a first sensor; detecting at least one depth map indicating the distance from the second sensor to each of a plurality of positions on the projection surface based on output from a second sensor during at least a portion of the first period; determining an orientation of the projection device relative to the projection surface based on the at least one depth map; and correcting distortion of the image based on the orientation when it is determined that the movement has stopped.

[0006] A control method according to a second aspect of the present invention is a control method for a projection device that projects an image onto a projection surface, and includes: receiving an instruction to correct distortion of the image via an operation device that operates the projection device; detecting at least one depth map that indicates distances from the sensor to each of multiple positions on the projection surface based on output from a sensor; determining an orientation of the projection device with respect to the projection surface based on the at least one depth map detected during at least a second period from a first point in time when the instruction is received to a second point in time prior to the first point in time; and correcting distortion of the image based on the orientation when the instruction is received via the operation device.

[0007] A projection device according to a first aspect of the present invention is a projection device that includes one or more processors and projects an image onto a projection surface, wherein the one or more processors perform the following actions: determine that movement of the projection device has stopped when, based on output from a first sensor, a parameter value indicating movement of the projection device remains less than a first threshold value for the first period; detect, during at least a portion of the first period, based on output from a second sensor, at least one depth map indicating the distance from the second sensor to each of a plurality of positions on the projection surface; determine an orientation of the projection device relative to the projection surface based on the at least one depth map; and correct distortion of the image based on the orientation when it is determined that the movement has stopped. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a block diagram showing an example of the configuration of a projection device 10A. [Figure 2] 10 is an explanatory diagram of an example of the operation of a determination unit 131A, a detection unit 132, a specification unit 133A, and a correction unit 134A. [Figure 3] 10 is an explanatory diagram of an example of the operation of a determination unit 131A, a detection unit 132, a specification unit 133A, and a correction unit 134A. [Figure 4] 10 is an explanatory diagram of an example of the operation of a determination unit 131A, a detection unit 132, a specification unit 133A, and a correction unit 134A. [Figure 5] 10 is an explanatory diagram of an example of the operation of a determination unit 131A, a detection unit 132, a specification unit 133A, and a correction unit 134A. [Figure 6] 10 is an explanatory diagram of an example of the operation of a determination unit 131A, a detection unit 132, a specification unit 133A, and a correction unit 134A. [Figure 7] 10 is a flowchart showing an example of the operation of the projection device 10A. [Figure 8] FIG. 2 is a block diagram showing an example of the configuration of a projection device 10B. [Figure 9] 10 is an explanatory diagram of an example of the operation of a determination unit 131B, a detection unit 132, an identification unit 133B, and a correction unit 134B. FIG. [Figure 10]10 is an explanatory diagram of an example of the operation of a determination unit 131B, a detection unit 132, an identification unit 133B, and a correction unit 134B. FIG. [Figure 11] 10 is a flowchart showing an example of the operation of the projection device 10B. [Figure 12] FIG. 2 is a block diagram showing an example of the configuration of a projection device 10C. [Figure 13] 10 is an explanatory diagram of an example of the operation of a determination unit 131C, a detection unit 132, an identification unit 133C, and a correction unit 134C. FIG. [Figure 14] 10 is an explanatory diagram of an example of the operation of a determination unit 131C, a detection unit 132, an identification unit 133C, and a correction unit 134C. FIG. [Figure 15] 10 is a flowchart showing an example of the operation of the projection device 10C. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in each drawing, the dimensions and scale of each part are appropriately different from those of the actual parts. Furthermore, since the embodiments described below are preferred specific examples of the present invention, various technically preferable limitations are applied, but the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description to the effect that the present invention is limited.

[0010] 1: First embodiment A projection device 10A according to a first embodiment will be described below with reference to FIGS.

[0011] 1-1: Configuration of the first embodiment 1 is a block diagram showing an example configuration of a projection device 10A. The projection device 10A includes a projector 110, a processing device 130A, a storage device 140A, a first sensor 150, a second sensor 160, and a communication device 170. The elements of the projection device 10A are connected to each other by one or more buses for communicating information. Furthermore, the elements of the projection device 10A are configured by one or more devices, and some elements of the projection device 10A may be omitted.

[0012] The projector 110 is a device that projects a projection image onto a projection surface such as a wall or a screen. The projector 110 projects various projection images under the control of the processing device 130A. The projector 110 includes, for example, a lighting device, a liquid crystal panel, and a projection lens system, and modulates light from the lighting device using the liquid crystal panel. The projector 110 also projects the modulated light onto the projection surface via the projection lens system.

[0013] The processing device 130A is a processor that controls the entire projection device 10A and is composed of, for example, one or more chips. The processing device 130A is composed of, for example, a central processing unit (CPU) that includes an interface with peripheral devices, an arithmetic unit, and registers. Note that some or all of the functions of the processing device 130A may be realized by hardware such as a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA). The processing device 130A executes various processes in parallel or sequentially.

[0014] The storage device 140A is a recording medium readable by the processing device 130A, and stores a plurality of programs including the control program PR1A executed by the processing device 130A. The storage device 140A may be configured with at least one of, for example, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), and a random access memory (RAM). The storage device 140A may also be called a register, a cache, a main memory, a primary storage device, or the like.

[0015] The first sensor 150 detects the movement of the projection device 10A and outputs the detected value to the processing device 130A. For example, the first sensor 150 may be an acceleration sensor or a gyro sensor, or may be an inertial measurement unit (IMU) that includes both an acceleration sensor and a gyro sensor. If the first sensor 150 is an acceleration sensor, the first sensor 150 detects the movement of the projection device 10A itself. If the first sensor 150 is a gyro sensor, the first sensor 150 detects the attitude of the projection device 10A in addition to the movement of the projection device 10A itself.

[0016] Second sensor 160 detects the distance from second sensor 160 to each of a plurality of positions on the projection surface. Second sensor 160 also outputs values ​​indicating the distances to storage device 140A. Second sensor 160 is, for example, a ToF (Time of Flight) sensor.

[0017] The communication device 170 is hardware serving as a transmitting / receiving device for communicating with other devices. The communication device 170 is also called, for example, a network device, a network controller, a network card, or a communication module. The communication device 170 includes a connector for wired connection. The communication device 170 may also include an interface for wireless communication. Examples of the interface for wireless communication include interfaces that comply with wireless LAN and Bluetooth. Furthermore, "Bluetooth" is a registered trademark.

[0018] The processing device 130A reads and executes the control program PR1A from the storage device 140A, thereby functioning as a determination unit 131A, a detection unit 132, an identification unit 133A, a correction unit 134A, a projection control unit 135, and a communication control unit 136. The control program PR1A may be transmitted via a communication network from another device, such as a server that manages the projection device 10A.

[0019] The determination unit 131A determines whether the motion of the projection device 10A has stopped based on the output from the first sensor 150. Specifically, the determination unit 131A calculates a parameter value indicating the motion of the projection device 10A based on the output from the first sensor 150. The determination unit 131A determines that the motion of the projection device 10A has stopped when the parameter value remains below a predetermined threshold for a predetermined period of time. The predetermined threshold is an example of a "first threshold." The predetermined period is also an example of a "first period." In this embodiment, the predetermined threshold and the predetermined period are fixed values, but may be values ​​that can be changed by the user.

[0020] When the first sensor 150 is an acceleration sensor, the parameter value is, for example, an acceleration value. When the first sensor 150 is a gyro sensor, the parameter value is, for example, an angular acceleration value. Furthermore, the parameter value may be an average value or a median value of these acceleration values ​​or angular acceleration values ​​over a predetermined period of time.

[0021] The detection unit 132 detects at least one depth map indicating the distance from the second sensor 160 to each of multiple positions on the projection surface during at least a predetermined period included in the first period. The predetermined period is an example of a "second period." The "second period" is also part of the "first period." That is, the detection unit 132 detects at least one depth map during the second period, which is part of the first period. The detection unit 132 may start detecting the at least one depth map from the first time point when it is determined that the parameter value indicating the movement of the projection device 10A is less than the predetermined threshold. However, the detection unit 132 may start detecting the at least one depth map from another time point. In other words, the detection unit 132 may detect at least one depth map during the entire first period. In other words, the detection unit 132 may detect at least one depth map during at least a part of the first period.

[0022] The determination unit 133A determines the orientation of the projection device 10A relative to the projection surface based on at least one depth map detected by the detection unit 132.

[0023] In addition, the determination unit 133A may determine the orientation of the projection device 10A relative to the projection surface based on at least one depth map that the detection unit 132 has detected up to that point only when the determination unit 131A determines that the movement of the projection device 10A has stopped. Alternatively, the determination unit 133A may constantly determine the orientation of the projection device 10A relative to the projection surface based on at least one depth map detected by the detection unit 132 until the determination unit 131A determines that the movement of the projection device 10A has stopped.

[0024] When the determination unit 131A determines that the motion of the projection device 10A has stopped, the correction unit 134A corrects distortion of the image projected by the projector 110 based on the orientation identified by the identification unit 133A. As an example, the correction unit 134A performs geometric correction on the image projected onto the projection surface based on the orientation identified by the identification unit 133A so that the image displayed on the projection surface becomes rectangular when the projector 110 projects the image onto the projection surface.

[0025] The correction unit 134A may calculate a correction value for correcting the distortion of the image during the second period. However, the correction unit 134A may calculate a correction value for correcting the distortion of the image during a period other than the second period.

[0026] 2 to 6 are explanatory diagrams of examples of the operations of the determining unit 131A, the detecting unit 132, the specifying unit 133A, and the correcting unit 134A.

[0027] In FIG. 2, a collection of rectangles located above the time axis indicating time t schematically shows the state of buffer BF at each point in time. As an example, buffer BF is a first-in, first-out buffer, such as a ring buffer. Buffer BF is included in storage device 140A. Buffer BF is an example of "memory." Buffer BF can freely update or change the data stored therein based on commands from processing device 130A.

[0028] The group of rectangles at the top indicates the state of data d1 and data d2 stored in buffer BF at time t=T1[1]. Details of data d1 and data d2 will be described later. The collection of rectangles in the second row indicates the state of data d1 and data d2 stored in buffer BF at t=T1[2]. The collection of rectangles in the third row indicates the state of data d1 and data d2 stored in buffer BF at t=T1[3]. The group of rectangles at the bottom indicates the state of data d1 and data d2 stored in buffer BF at t=T1[4]. The broken line positioned below the time axis indicating time t indicates the change over time in acceleration g sensed by first sensor 150.

[0029] 2, at time t=T1[0], the acceleration g becomes less than the threshold value r, and thereafter, the acceleration g continues to be less than the threshold value r. At time t=T1[0], the determination unit 131A starts a stop determination to determine whether the motion of the projection device 10A has stopped. After that, from time t=T1[0] to time t=T1[4], which is after the stop determination period SP, the acceleration g continues to be less than the threshold value r, and therefore, at time t=T1[4], the determination unit 131A determines that the motion of the projection device 10A has stopped.

[0030] At t=T[1], which is later than time t=T[0], nine frames of data d1 and eight frames of data d2 are stored in the buffer BF. Here, each of the nine frames of data d1 is data including a depth map detected by the detection unit 132, which was stored in the buffer BF during a period in which the acceleration g was equal to or greater than the threshold value r. In the example shown in FIG. 2, the data d1 is data including a depth map that was stored in the buffer BF before time t=T1[0]. The data d1 is an example of "first data based on the output from the second sensor before the first period." On the other hand, each of the eight frames of data d2 is data including a depth map detected by the detection unit 132 and stored in the buffer BF during a period in which the acceleration g is less than the threshold value r. In the example shown in FIG. 2, the data d2 is data including a depth map that has been stored in the buffer BF after time t=T1[0]. The data d2 is an example of "second data based on the output from the second sensor during at least a part of the first period."

[0031] In this embodiment, data including a depth map is stored in the buffer BF in real time. Therefore, at time t=T1[0], data d1 obtained when the projection device 10A is moving may already be stored. Therefore, in this embodiment, if data d1 based on output from the second sensor 160 prior to the first period is stored in the buffer BF at time t=T1[0], the processing device 130A causes the buffer BF to sequentially update the data d1 to data d2 based on output from the second sensor during at least a portion of the first period.

[0032] At time t=T1[2], which is later than time t=T1[1], eight frames of data d1 and nine frames of data d2 are stored in the buffer BF. At time t=T1[3], which is later than time t=T1[2], seven frames of data d1 and ten frames of data d2 are stored in the buffer BF. At time t=T1[4], which is later than time t=T1[3], 6 frames of data d1 and 11 frames of data d2 are stored in the buffer BF. That is, from time t=T1[0] onwards, data d1 is successively updated to data d2, and at time t=T1[4], it is replaced with data d2 based on the output from the second sensor in the first period.

[0033] Note that the above-mentioned number of frames of data d1 and data d2 stored in buffer BF is merely an example for the schematic explanation. The same applies to the following figures. Furthermore, if data including a depth map is not stored in buffer BF in real time, for example, if data starts to be stored in buffer BF from the first time that acceleration g becomes less than threshold r at time t=T1[0], the above-mentioned update does not need to be performed.

[0034] The determination unit 133A determines the orientation of the projection device 10A relative to the projection surface based on the depth map included in the 11 frames of data d2 at time t=T1[4].

[0035] In addition, the determination unit 133A may determine the orientation of the projection device 10A relative to the projection surface at each point in time from time t=T1[1] to time t=T1[3] based on the depth map contained in the data d2 stored in the buffer BF up to that point. Specifically, the determination unit 133A may determine the orientation of the projection device 10A relative to the projection surface at time t=T1[1] based on the depth map included in the eight frames of data d2. Furthermore, the determination unit 133A may determine the orientation of the projection device 10A relative to the projection surface based on the depth map included in the nine frames of data d2 at time t=T1[2]. Furthermore, the determination unit 133A may determine the orientation of the projection device 10A relative to the projection surface based on the depth map included in the 10 frames of data d2 at time t=T1[3].

[0036] At time t=T1[4], the correction unit 134A starts calculation to correct the distortion of the image projected by the projector 110 based on the orientation identified by the identification unit 133A.

[0037] 2, the first period corresponds to the stop determination period SP, the second period also corresponds to the stop determination period SP, and the first threshold corresponds to the threshold r.

[0038] 2, the detection unit 132 may start detecting the depth map from time t=T1[0], which is the first time point at which it is determined that the acceleration g is less than the threshold value r. Furthermore, in FIG. 2, the correction unit 134A may calculate a correction value for correcting distortion of the image projected from the projector 110 during the stop determination period SP, which is also the second period.

[0039] 3 is a diagram showing a case where the projection device 10A moves during the stop determination period SP. As shown in FIG. 3, it is assumed that the acceleration g becomes less than the threshold value r at time t=T2[0]. In FIG. 3, it is assumed that the time after the stop determination period SP from time t=T2[0] is time t=T2[2].

[0040] As shown in FIG. 3, assume that at time t=T2[1], acceleration g again exceeds threshold value r. At this time, 12 frames of data d1 and 5 frames of data d2 are stored in buffer BF. In this case, determination unit 133A does not determine the orientation of projection device 10A relative to the projection surface based on 5 frames of data d2. As a result, correction unit 134A does not correct distortion of the image projected by projector 110 until it is determined that the motion of projection device 10A has stopped at a point after time t=T2[1].

[0041] In FIG. 3, after time t=T2[1], data d1 or data d2 continues to be stored in the buffer BF.

[0042] FIG. 4 is a diagram showing a case where all of the data d2 stored in the buffer BF during the stop determination period SP is used as correction data.

[0043] As shown in Fig. 4, it is assumed that the acceleration g becomes less than the threshold value r at time t=T3[0]. In Fig. 4, it is assumed that the time after the stop determination period SP has elapsed from time t=T3[0] is time t=T3[1].

[0044] As shown in FIG. 4, the acceleration g remains below the threshold value r throughout the stoppage determination period SP, so the determination unit 131A determines that the projection device 10A has come to a standstill at time t=T3[1].

[0045] For example, the determination unit 133A determines the orientation of the projection device 10A relative to the projection surface based on the depth map indicated by the 11 frames of data d2 at time t=T3[1].

[0046] At time t=T3[1], the correction unit 134A starts calculation to correct the distortion of the image projected by the projector 110 based on the orientation identified by the identification unit 133A.

[0047] 4, the first period corresponds to the stop determination period SP, the second period also corresponds to the stop determination period SP, and the first threshold corresponds to the threshold r.

[0048] 4, the detection unit 132 may start detecting the depth map from time t=T3[0], which is the first time point at which it is determined that the acceleration g is less than the threshold value r. Furthermore, in FIG. 4, the correction unit 134A may calculate a correction value for correcting distortion of the image projected from the projector 110 during the stop determination period SP, which is also the second period.

[0049] 5 is a diagram showing a case where all of the data d2 stored in the buffer BF during the stop determination period SP and the data d3 are used as correction data. Details of the data d3 will be described later.

[0050] Assume that the acceleration g becomes less than the threshold value r at time t=T4[0] as shown in Fig. 5. Also, in Fig. 5, the time after the stop determination period SP has elapsed from time t=T4[0] is time t=T4[1].

[0051] As shown in FIG. 5, the acceleration g remains below the threshold value r throughout the stoppage determination period SP, so the determination unit 131A determines that the motion of the projection device 10A has stopped at time t=T4[1].

[0052] As an example, the determination unit 133A attempts to determine the orientation of the projection device 10A relative to the projection surface based on the depth map indicated by 11 frames of data d2 at time t=T4[1], but is unable to determine the orientation of the projection device 10A because the accuracy of the 11 frames of data d2 is insufficient.

[0053] In this case, for example, the determination unit 133A determines the orientation of the projection device 10A with respect to the projection surface based on the 11 frames of data d2 and the 4 frames of data d3 stored in the buffer BF during the additional period DP from time t=T4[1] to time t=T4[2]. Note that it is assumed that the acceleration g remains below the threshold value r during the period from time t=T4[1] to time t=T4[2].

[0054] Here, each of the four frames of data d3 is data including a depth map detected by the detection unit 132, which is stored in the buffer BF during the additional period DP after it is determined that the acceleration g is less than the threshold value r and that the movement of the projection device 10A has stopped.

[0055] The criterion for determining whether the "accuracy" is sufficient or insufficient is, for example, whether the determination unit 133A can determine the orientation of the projection device 10A with respect to the projection surface based on depth maps included in data d2 of at least a predetermined number of frames. The "predetermined number of frames" may be determined based on the accuracy of the second sensor 160 itself. Alternatively, the "predetermined number of frames" may be a function of the distance from the second sensor 160 to the projection surface. Alternatively, the "predetermined number of frames" may be determined based on whether the distance from the second sensor 160 to the projection surface exceeds a threshold.

[0056] Alternatively, the above "accuracy" may be determined based on the accuracy of the depth map itself included in the 11 frames of data d2 stored in the buffer BF.

[0057] The same applies to the "accuracy" shown in the following examples.

[0058] At time t=T4[2], the correction unit 134A starts calculation to correct the distortion of the image projected by the projector 110 based on the orientation identified by the identification unit 133A.

[0059] 5, the first period corresponds to the stop determination period SP, the second period also corresponds to the stop determination period SP, and the first threshold corresponds to the threshold r.

[0060] 5, the detection unit 132 may start detecting the depth map from time t=T4[0], which is the first time point at which it is determined that the acceleration g is less than the threshold value r. Furthermore, in FIG. 5, the correction unit 134A may calculate a correction value for correcting distortion of the image projected from the projector 110 during the stop determination period SP, which is also the second period.

[0061] FIG. 6 is a diagram showing a case where only a part of the data d2 stored in the buffer BF during the stop determination period SP is used as correction data.

[0062] As shown in Fig. 6, it is assumed that the acceleration g becomes less than the threshold value r at time t=T5[0]. In Fig. 6, it is assumed that the time after the stop determination period SP has elapsed from time t=T5[0] is time t=T5[1].

[0063] As shown in Fig. 6, at time t=T5[1] between time t=T5[0] and time t=T5[2], it is assumed that 10 frames of data d1 and 7 frames of data d2 are stored in buffer BF. Also, at time t=T5[2], similar to time t=T3[1] in Fig. 4, it is assumed that 6 frames of data d1 and 11 frames of data d2 are stored in buffer BF. In other words, at time t=T5[1] in Fig. 6, only a portion of the 11 frames of data d2 that will be stored in buffer BF at time t=T5[2], when it is determined that projection device 10A has come to a standstill, is stored.

[0064] However, if the accuracy of the seven frames of data d2 stored in the buffer BF is sufficiently high at time t=T5[1], the determination unit 133A determines the orientation of the projection device 10A based on the depth map contained in these seven frames of data d2 at time t=T5[1].

[0065] At time t=T5[1], the correction unit 134A starts calculations to correct distortion of the image projected by the projector 110 based on the orientation identified by the identification unit 133A. As a result, it is preferable that the correction unit 134A completes the correction process at time t=T5[2]. In this case, the correction process by the correction unit 134A will have already been completed by the time the determination unit 131A determines that the motion of the projection device 10A has stopped.

[0066] 6, the first period corresponds to the stop determination period SP, the second period corresponds to the period from time t=T5[0] to time t=T5[1], and the first threshold corresponds to threshold r.

[0067] 6, the detection unit 132 may start detecting the depth map from time t=T5[0], which is the first time point at which it is determined that the acceleration g is less than the threshold value r. Furthermore, in FIG. 6, the correction unit 134A may calculate a correction value for correcting distortion of the image projected from the projector 110 during the second period from time t=T5[0] to time t=T5[1].

[0068] In FIG. 1, the projection control unit 135 causes the projector 110 to project the image corrected by the correction unit 134A onto the projection surface.

[0069] The communication control unit 136 uses the communication device 170 to transmit and receive various types of data to and from external devices of the projection device 10A.

[0070] 1-2: Operation of the first embodiment FIG. 7 is a flowchart showing an example of the operation of the projection device 10A.

[0071] In step S1, the processing device 130A functions as a determination unit 131A. The processing device 130A determines whether the motion of the projection device 10A has stopped based on the output from the first sensor 150. Specifically, the processing device 130A calculates a parameter value indicating the motion of the projection device 10A based on the output from the first sensor 150. The processing device 130A determines that the motion of the projection device 10A has stopped when the parameter value remains below a predetermined threshold for a first period of time. If the processing device 130A determines that the motion of the projection device 10A has stopped (YES in step S1), the processing device 130A performs the operation of step S2. On the other hand, if the processing device 130A does not determine that the motion of the projection device 10A has stopped (NO in step S1), the processing device 130A performs the operation of step S1.

[0072] In step S2, the processing device 130A functions as the detection unit 132. The processing device 130A detects, at least during a second period, at least one depth map indicating the distance from the second sensor 160 to each of a plurality of positions on the projection surface.

[0073] In step S3, the processing device 130A functions as the determination unit 133A. The processing device 130A determines the orientation of the projection device 10A with respect to the projection surface based on at least one depth map detected in step S2.

[0074] In step S4, the processing device 130A functions as the correction unit 134A. The processing device 130A corrects the distortion of the image projected by the projector 110 based on the orientation identified in step S3.

[0075] 2: Second embodiment A projection device 10B according to the second embodiment will be described below with reference to Figures 8 to 11. For simplicity of explanation, differences between the projection device 10B according to this embodiment and the projection device 10A according to the first embodiment will be mainly described below. Furthermore, among the components provided in the projection device 10B according to this embodiment, the same components as those provided in the projection device 10A according to the first embodiment will be designated by the same reference numerals, and explanations of their functions may be omitted.

[0076] In the projection device 10A according to the first embodiment, the image projected by the projector 110 is corrected when it is determined that the motion of the projection device 10A has stopped. On the other hand, in the projection device 10B according to the present embodiment, the image projected by the projector 110 is corrected when a user operates an operation device 180 (described later) provided in the projection device 10B.

[0077] 2-1: Configuration of the second embodiment 8 is a block diagram showing an example of the configuration of the projection device 10B. Unlike the projection device 10A, the projection device 10B includes a processing device 130B instead of the processing device 130A, and a storage device 140B instead of the storage device 140A. The projection device 10B also includes an operation device 180 in addition to the projector 110, the processing device 130B, the storage device 140B, the first sensor 150, the second sensor 160, and the communication device 170.

[0078] The storage device 140B stores the control program PR1B instead of the control program PR1A stored in the storage device 140A.

[0079] The operation device 180 is a device used by a user of the projection device 10B to operate the projection device 10B. The operation device 180 is, for example, a remote controller that transmits and receives signals by wireless communication with the processing device 130B. Instructions corresponding to operations performed by the user using the operation device 180 are input to the processing device 130B. In this embodiment, the operation device 180 inputs an instruction to correct the distortion of the image to the processing device 130B based on an operation by the user. The operation device 180 is an example of an "operation device."

[0080] The processing device 130B reads and executes the control program PR1B from the storage device 140B, thereby functioning as a determination unit 131B, a detection unit 132, an identification unit 133B, a correction unit 134B, a projection control unit 135, a communication control unit 136, and a reception unit 137. The control program PR1B may be transmitted via a communication network from another device, such as a server that manages the projection device 10B.

[0081] The receiving unit 137 receives, via the operation device 180, an instruction to correct the distortion of an image.

[0082] Similar to the determination unit 131A, the determination unit 131B determines whether the motion of the projection device 10B has stopped. The determination unit 131B also determines whether the reception unit 137 has received, via the operation device 180, an instruction to correct the distortion of the image.

[0083] The determination unit 133B may determine the orientation of the projection device 10B relative to the projection surface based on at least one depth map that the detection unit 132 has detected up to that point only after the determination unit 131B determines that the movement of the projection device 10B has stopped and the determination unit 131B determines that the reception unit 137 has received an instruction to correct the distortion of the image. Alternatively, the determination unit 133B may constantly determine the orientation of the projection device 10B relative to the projection surface based on at least one depth map detected by the detection unit 132 until the determination unit 131B determines that the movement of the projection device 10B has stopped and the reception unit 137 determines that an instruction to correct the distortion of the image has been received.

[0084] When the determination unit 131B determines that the movement of the projection device 10B has stopped and the reception unit 137 has received an instruction to correct the distortion of the image, the correction unit 134B corrects the distortion of the image projected by the projector 110 based on the direction identified by the identification unit 133B.

[0085] The timing at which corrector 134B corrects the image distortion may be synchronized with the timing at which acceptor 137 accepts an instruction to correct the image distortion.

[0086] 9 and 10 are explanatory diagrams of examples of the operations of the determination unit 131B, the detection unit 132, the identification unit 133B, and the correction unit 134B.

[0087] As shown in Fig. 9, it is assumed that the acceleration g becomes less than the threshold value r at time t=T6[0]. In Fig. 9, it is assumed that the time after the stop determination period SP from time t=T6[0] is time t=T6[1].

[0088] Here, it is assumed that at time t=T6[2], the receiving unit 137 receives an instruction to correct image distortion from the operation device 180. It is assumed that the acceleration g remains below the threshold value r from time t=T6[1] to time t=T6[2].

[0089] At time t=T6[2], the determination unit 133B determines the orientation of the projection device 10B relative to the projection surface based on the depth map indicated by all of the 11 frames of data d2 stored in the buffer BF.

[0090] At time t=T6[2], the correction unit 134B starts calculations for correcting distortion of the image projected by the projector 110 based on the orientation identified by the identification unit 133B.

[0091] The time t=T6[2] at which the correction unit 134B starts calculations to correct the distortion of the image projected by the projector 110 is the same as the time t=T6[2] at which the reception unit 137 receives an instruction from the operation device 180 to correct the distortion of the image.

[0092] 10 is a diagram showing a case where all of the data d2 stored in the buffer BF and the data d4 are used as correction data when the receiving unit 137 receives an instruction to correct image distortion from the operation device 180. Details of the data d4 will be described later.

[0093] As shown in Fig. 10, it is assumed that the acceleration g becomes less than the threshold value r at time t=T7[0]. In Fig. 10, it is assumed that the time after the stop determination period SP from time t=T7[0] is time t=T7[1].

[0094] Here, it is assumed that at time t=T7[2], the receiving unit 137 receives an instruction to correct image distortion from the operation device 180. It is assumed that the acceleration g remains below the threshold value r from time t=T7[1] to time t=T7[2].

[0095] At time t=T7[2], the determination unit 133B attempts to determine the orientation of the projection device 10B relative to the projection surface based on the depth maps contained in all 11 frames of data d2 stored in the buffer BF, but is unable to determine the orientation of the projection device 10B because the accuracy of the 11 frames of data d2 is insufficient.

[0096] In this case, as an example, the determination unit 133B determines the orientation of the projection device 10B relative to the projection surface based on 11 frames of data d2 as well as 4 frames of data d4 stored in the buffer BF during the additional period DP from time t=T7[2] to time t=T7[3].

[0097] Here, each of the four frames of data d4 is data including a depth map detected by the detection unit 132, the acceleration g of which is less than the threshold value r, and which is stored in the buffer BF during the additional period DP after the reception unit 137 receives an instruction from the operation device 180 to correct the distortion of the image.

[0098] At time t=T7[3], the correction unit 134B starts calculations for correcting distortion of the image projected by the projector 110 based on the orientation identified by the identification unit 133B.

[0099] 2-2: Operation of the second embodiment FIG. 11 is a flowchart showing an example of the operation of the projection device 10B.

[0100] In step S11, the processing device 130B functions as a determination unit 131B. The processing device 130B determines whether the movement of the projection device 10B has stopped based on the output from the first sensor 150. Specifically, the processing device 130B determines that the movement of the projection device 10B has stopped when, based on the output from the first sensor 150, a state in which a parameter value indicating the movement of the projection device 10B is less than a predetermined threshold continues for a first period. If the processing device 130B determines that the movement of the projection device 10B has stopped (YES in step S11), the processing device 130B performs the operation of step S12. On the other hand, if the processing device 130B does not determine that the movement of the projection device 10B has stopped (NO in step S11), the processing device 130B performs the operation of step S11.

[0101] In step S12, the processing device 130B functions as the detection unit 132. The processing device 130B detects at least one depth map indicating the distance from the second sensor 160 to each of a plurality of positions on the projection surface.

[0102] In step S13, the processing device 130B functions as a determination unit 131B. The processing device 130B determines whether the receiving unit 137 has received an instruction to correct the distortion of the image via the operation device 180. If the processing device 130B determines that the receiving unit 137 has received an instruction to correct the distortion of the image (YES in step S13), the processing device 130B performs the operation of step S14. On the other hand, if the processing device 130B has not determined that the receiving unit 137 has received an instruction to correct the distortion of the image (NO in step S13), the processing device 130B performs the operation of step S12.

[0103] In step S14, the processing device 130B functions as the determination unit 133B. The processing device 130B determines the orientation of the projection device 10B with respect to the projection surface based on at least one depth map detected in step S12.

[0104] In step S15, the processing device 130B functions as the correction unit 134B. The processing device 130B corrects distortion of the image projected by the projector 110 based on the orientation identified in step S14.

[0105] 3: Third embodiment A projection device 10C according to the third embodiment will be described below with reference to Figures 12 to 15. Note that, for simplicity of explanation, the following mainly describes the differences between the projection device 10C according to this embodiment and the projection device 10A according to the first embodiment and the projection device 10B according to the second embodiment. Furthermore, of the components provided in the projection device 10C according to this embodiment, the same components as those provided in the projection device 10A according to the first embodiment and the projection device 10B according to the second embodiment will be denoted by the same reference numerals, and a description of their functions may be omitted.

[0106] The projection device 10A according to the first embodiment and the projection device 10B according to the second embodiment are equipped with two sensors: a first sensor 150 that detects the movement of the projection device 10A, and a second sensor 160 that detects the distance to each of a plurality of positions on the projection surface. On the other hand, the projection device 10C according to the present embodiment does not have the first sensor 150, as will be described later, and does not determine whether the movement of the projection device 10C has stopped.

[0107] 3-1: Configuration of the third embodiment 12 is a block diagram showing an example of the configuration of the projection device 10C. Unlike the projection device 10B, the projection device 10C includes a processing device 130C instead of the processing device 130B, and a storage device 140C instead of the storage device 140B. The projection device 10C also includes a projector 110, the processing device 130C, the storage device 140C, a second sensor 160, a communication device 170, and an operation device 180. In other words, the projection device 10C does not include the first sensor 150.

[0108] The storage device 140C stores the control program PR1C instead of the control program PR1B stored in the storage device 140B.

[0109] The processing device 130C reads and executes the control program PR1C from the storage device 140C, thereby functioning as a determination unit 131C, a detection unit 132, an identification unit 133C, a correction unit 134C, a projection control unit 135, a communication control unit 136, and a reception unit 137. The control program PR1B may be transmitted via a communication network from another device, such as a server that manages the projection device 10A.

[0110] The determination unit 131C determines whether the reception unit 137 has received an instruction to correct image distortion via the operation device 180. However, unlike the determination units 131A and 131B, the determination unit 131C does not determine whether the motion of the projection device 10B has stopped.

[0111] The determination unit 133C may determine the orientation of the projection device 10C relative to the projection surface based on at least one depth map that the detection unit 132 has detected up to that point only after the determination unit 131C determines that the reception unit 137 has received an instruction to correct image distortion. Alternatively, the determination unit 133C may constantly determine the orientation of the projection device 10C relative to the projection surface based on at least one depth map detected by the detection unit 132 until the determination unit 131C determines that the reception unit 137 has received an instruction to correct image distortion.

[0112] When the determination unit 131C determines that the reception unit 137 has received an instruction to correct the distortion of the image, the correction unit 134C corrects the distortion of the image projected by the projector 110 based on the direction identified by the identification unit 133C.

[0113] The timing at which corrector 134C corrects the image distortion may be synchronized with the timing at which acceptor 137 accepts an instruction to correct the image distortion.

[0114] 13 and 14 are explanatory diagrams of examples of the operations of the determination unit 131C, the detection unit 132, the identification unit 133C, and the correction unit 134C.

[0115] 13, it is assumed that the receiving unit 137 receives an instruction to correct image distortion from the operation device 180. It is assumed that the user of the projection device 10C expects that the movement of the projection device 10C will have stopped by the time t=T8[0].

[0116] The determination unit 133C determines the orientation of the projection device 10C relative to the projection surface based on the depth maps included in all of the 11 frames of data d2 stored in the buffer BF at time t=T8[0].

[0117] At time t=T8[0], the correction unit 134C starts calculations for correcting distortion of the image projected by the projector 110 based on the orientation identified by the identification unit 133C.

[0118] The time t=T8[0] at which the correction unit 134C starts calculations to correct the distortion of the image projected by the projector 110 is the same as the time t=T8[0] at which the reception unit 137 receives an instruction from the operation device 180 to correct the distortion of the image.

[0119] 14 is a diagram showing a case where all of the data d2 stored in the buffer BF and the data d5 are used as correction data when the receiving unit 137 receives an instruction to correct image distortion from the operation device 180. Details of the data d5 will be described later.

[0120] 14, it is assumed that the receiving unit 137 receives an instruction to correct image distortion from the operation device 180. It is assumed that the user of the projection device 10C expects that the movement of the projection device 10C will have stopped by the time t=T8[0].

[0121] At time t=T8[0], the determination unit 133C attempts to determine the orientation of the projection device 10C relative to the projection surface based on the depth maps contained in all 11 frames of data d2 stored in the buffer BF, but is unable to determine the orientation of the projection device 10C because the accuracy of the 11 frames of data d2 is insufficient.

[0122] In this case, the determination unit 133C, for example, determines the orientation of the projection device 10C relative to the projection surface based on the depth map indicated by the 11 frames of data d2 as well as the 4 frames of data d5 stored in the buffer BF during the additional period DP from time t=T8[0] to time t=T8[1].

[0123] Here, each of the four frames of data d5 is data including a depth map detected by the detection unit 132, which is stored in the buffer BF during the additional period DP after the reception unit 137 receives an instruction from the operation device 180 to correct the distortion of the image.

[0124] At time t=T8[1], the correction unit 134C starts calculations for correcting distortion of the image projected by the projector 110 based on the orientation identified by the identification unit 133C.

[0125] 3-2: Operation of the third embodiment FIG. 15 is a flowchart showing an example of the operation of the projection device 10C.

[0126] In step S21, processing device 130C functions as detection unit 132. Processing device 130C detects at least one depth map indicating the distance from second sensor 160 to each of a plurality of positions on the projection surface.

[0127] In step S22, the processing device 130C functions as a determination unit 131C. The processing device 130C determines whether the receiving unit 137 has received an instruction to correct the distortion of the image via the operation device 180. If the processing device 130C determines that the receiving unit 137 has received an instruction to correct the distortion of the image (YES in step S22), the processing device 130C performs the operation of step S23. On the other hand, if the processing device 130C has not determined that the receiving unit 137 has received an instruction to correct the distortion of the image (NO in step S22), the processing device 130B performs the operation of step S21.

[0128] In step S23, the processing device 130C functions as an identification unit 133C. The processing device 130C identifies the orientation of the projection device 10C with respect to the projection surface based on at least one depth map detected in step S21.

[0129] In step S24, processing device 130C functions as correction unit 134C. Processing device 130C corrects distortion of the image projected by projector 110 based on the orientation identified in step S23.

[0130] 4: Variation The above embodiments can be modified in various ways. Specific modified embodiments are exemplified below. The embodiments exemplified below and the embodiments described above can be combined as appropriate within the scope of not mutually contradicting each other. Note that for elements in the modified embodiments exemplified below that have the same actions and functions as the embodiments, the reference numerals referenced in the above explanation will be used and detailed explanations of each element will be omitted as appropriate.

[0131] 4-1: Variation 1 In the projection device 10A according to the first embodiment, the determination unit 131A, the detection unit 132, the identification unit 133A, and the correction unit 134A are provided in the processing device 130A. However, the determination unit 131A, the detection unit 132, the identification unit 133A, and the correction unit 134A may be provided in an external device separate from the projection device 10A. As an example, the determination unit 131A, the detection unit 132, the identification unit 133A, and the correction unit 134A may be provided in a control device that controls the projection device 10A. In this case, the control device receives the output from the first sensor 150 and the output from the second sensor 160 from the projection device 10A via a communication network. The control device also transmits the output from the correction unit 134A to the projection device 10A via the communication network.

[0132] The same applies to the projection device 10B according to the second embodiment and the projection device 10C according to the third embodiment.

[0133] 4-2: Variation 2 In the projection device 10A according to the first embodiment, the identification unit 133A identifies the orientation of the projection device 10A relative to the projection surface based on at least one depth map detected by the detection unit 132.

[0134] The determination unit 133A may determine only one orientation of the projection device 10A relative to the projection surface based on at least one depth map detected by the detection unit 132. Alternatively, there may be a one-to-one correspondence between at least one depth map detected by the detection unit 132 and the orientation of the projection device 10A identified by the identification unit 133A. In this case, the identification unit 133A identifies one orientation based on one depth map. Furthermore, the number of depth maps detected by the detection unit 132 is the same as the number of orientations of the projection device 10A identified by the identification unit 133A.

[0135] When the specifying unit 133A specifies a plurality of orientations of the projection device 10A relative to the projection surface, the correcting unit 134A corrects distortion of the image projected by the projector 110 based on the plurality of orientations specified by the specifying unit 133A.

[0136] The same applies to the projection device 10B according to the second embodiment and the projection device 10C according to the third embodiment.

[0137] 4-3: Variation 3 In the projection device 10A according to the first embodiment, the correction unit 134A corrects distortion of the image projected by the projector 110 based on the direction identified by the identification unit 133A. However, the correction unit 134A may calculate a gravity vector based on the output from the first sensor 150, and correct distortion of the image projected by the projector 110 based on the gravity vector.

[0138] In this case, as an example, the data d1 and data d2 shown in FIG. 2 include the above-mentioned gravity vector.

[0139] Alternatively, the correction unit 134A may correct the distortion of the image projected by the projector 110 based on both the orientation identified by the identification unit 133A and the above-mentioned gravity vector.

[0140] In this case, as an example, the data d1 and data d2 shown in FIG. 2 include the above-mentioned depth map and the above-mentioned gravity vector.

[0141] The same applies to the projection device 10B according to the second embodiment.

[0142] 4-4: Variation 4 In the projection device 10A according to the first embodiment, it is determined that the movement of the projection device 10A has stopped when a state in which a parameter value indicating the movement of the projection device 10A is less than a first threshold value continues for a first period based on the output from the first sensor 150. However, the projection device 10A may also determine that the movement of the projection device 10A has stopped when a state in which a parameter value indicating the movement of the projection device 10A is less than the first threshold value continues for a first period based on the output from the second sensor 160.

[0143] The same applies to the projection device 10B according to the second embodiment.

[0144] 4-5: Variation 5 In the projection device 10B according to the second embodiment, if there is sufficient time for the motion of the projection device 10B to remain stopped after the determination unit 131B determines that the motion of the projection device 10B has stopped until the reception unit 137 receives an instruction to correct the distortion of the image, the determination unit 133B may perform the identification process and the correction unit 134B may perform the calculation process for correction before the reception unit 137 receives the instruction. In this case, the correction unit 134B can correct the distortion of the image projected by the projector 110 at the same time that the reception unit 137 receives the instruction.

[0145] 5: Summary of this disclosure A summary of this disclosure is provided below.

[0146] (Supplementary Note 1) A control method for a projection device that projects an image onto a projection surface, the control method including: determining that the movement of the projection device has stopped when a parameter value indicating the movement of the projection device remains less than a first threshold value for a first period based on an output from a first sensor; detecting at least one depth map indicating a distance from the second sensor to each of a plurality of positions on the projection surface based on an output from a second sensor during at least a part of the first period; determining an orientation of the projection device with respect to the projection surface based on the at least one depth map; and correcting distortion of the image based on the orientation when it is determined that the movement has stopped.

[0147] By virtue of the above-described configuration, the control method of this embodiment starts measuring the information necessary to perform geometric correction before the conditions that trigger geometric correction are satisfied, and therefore the time required to complete geometric correction is shorter than with conventional technology.

[0148] More specifically, according to the control method of this embodiment, the projection device acquires at least one depth map during a first period, which is a period for determining that the motion of the main body has stopped. As a result, the control method of this embodiment can shorten the time it takes to identify the orientation of the projection device relative to the projection surface, compared to conventional techniques that project a distance detection pattern to identify the orientation of the projection device relative to the projection surface after the first period has elapsed and then capture an image.

[0149] (Supplementary Note 2) A control method for a projection device that projects an image onto a projection surface, the control method including: receiving an instruction to correct distortion of the image via an operation device that operates the projection device; detecting at least one depth map that indicates distances from the sensor to each of a plurality of positions on the projection surface based on output from a sensor; determining an orientation of the projection device with respect to the projection surface based on the at least one depth map detected during at least a second period from a first point in time when the instruction is received to a second point in time prior to the first point in time; and correcting distortion of the image based on the orientation when the instruction is received via the operation device.

[0150] By virtue of the above-described configuration, the control method of this embodiment starts measuring the information necessary to perform geometric correction before the conditions that trigger geometric correction are satisfied, and therefore the time required to complete geometric correction is shorter than with conventional technology.

[0151] More specifically, according to the control method of this embodiment, the projection device acquires a depth map during a period from a first time point at which the projection device receives a response instruction to correct image distortion to a second time point prior to the first time point, so that when the projection device receives an instruction to correct image distortion, the projection device can correct the image using the depth map. This allows the projection device to reduce the time it takes to identify the orientation of the projection device relative to the projection surface compared to when the projection device starts acquiring a depth map after the first time point at which the instruction is received.

[0152] (Supplementary Note 3) The control method of Supplementary Note 1 further includes, during at least a portion of the first period, calculating a correction value for correcting distortion of the image based on the detection result of the at least one depth map.

[0153] The control method of this embodiment has the above-mentioned configuration, and therefore the correction value is calculated in the first period, thereby further reducing the time required to correct image distortion compared to when the correction value is calculated after the first period.

[0154] (Supplementary Note 4) The control method of Supplementary Note 1, wherein detecting the at least one depth map begins from the first time it is determined that the parameter value is less than the first threshold.

[0155] The control method of this embodiment has the above configuration, so that the projection device does not acquire a depth map before the first time that it is determined that the parameter value is less than the first threshold, thereby reducing unnecessary data.

[0156] (Appendix 5) A control method according to Appendix 1, which receives an instruction to correct distortion of the image via an operation device that operates the projection device, and corrects distortion of the image based on the orientation when it is determined that the movement has stopped.

[0157] The control method of this embodiment has the above-mentioned configuration, so that the projection device can correct the image in association with receiving instructions via an operation device that operates the projection device, thereby improving operability for the user.

[0158] (Appendix 6) The control method of Appendix 5, wherein the timing of correcting the distortion of the image is synchronized with the timing of receiving an instruction to correct the distortion of the image via an operation device that operates the projection device.

[0159] The control method of this embodiment has the above-described configuration, and therefore the projection device can correct distortion at the same time as receiving an instruction, further reducing the time required for correction.

[0160] (Appendix 7) The control method of Appendix 1 includes, when first data based on output from the second sensor prior to the first period is stored in a memory, updating the first data to second data based on output from the second sensor during at least a portion of the first period, and detecting the at least one depth map includes detecting the at least one depth map based on the second data.

[0161] The control method of this embodiment has the above configuration, and therefore can prevent image distortion from being corrected based on the first data when the projection device is moving, thereby improving the accuracy of correction.

[0162] (Supplementary Note 8) A projection device comprising one or more processors that projects an image onto a projection surface, wherein the one or more processors perform the following operations: determine that movement of the projection device has stopped when a parameter value indicating movement of the projection device remains less than a first threshold value for the first period based on output from a first sensor; detect at least one depth map indicating distances from the second sensor to each of a plurality of positions on the projection surface based on output from a second sensor during at least a portion of the first period; identify an orientation of the projection device with respect to the projection surface based on the at least one depth map; and correct distortion of the image based on the orientation when it is determined that the movement has stopped.

[0163] By being equipped with the above-described configuration, the projection device of this embodiment begins measuring the information necessary to perform geometric correction before the conditions that trigger geometric correction are met, thereby shortening the time it takes to complete geometric correction compared to conventional technology.

[0164] More specifically, the projection device of this embodiment acquires at least one depth map during a first period, which is a period for determining that the motion of the main body has stopped. As a result, the control method of this embodiment can shorten the time it takes to identify the orientation of the projection device relative to the projection surface, compared to conventional techniques that project a distance detection pattern to identify the orientation of the projection device relative to the projection surface after the first period has elapsed and then perform imaging. [Explanation of symbols]

[0165] 10A: projection device, 10B: projection device, 10C: projection device, 110: projector, 130A: processing device, 130B: processing device, 130C: processing device, 131A: determination unit, 131B: determination unit, 131C: determination unit, 132: detection unit, 133A: identification unit, 133B: identification unit, 133C: identification unit, 134A: correction unit, 134B: correction unit, 134C: correction unit, 135: projection control unit, 136: communication control unit, 137: Reception unit, 140A: Storage device, 140B: Storage device, 140C: Storage device, 150: First sensor, 160: Second sensor, 170: Communication device, 180: Operation device, BF: Buffer, DP: Additional period, PR1A: Control program, PR1B: Control program, PR1C: Control program, d1: Data, d2: Data, d3: Data, d4: Data, d5: Data, g: Acceleration, r: Threshold

Claims

1. A method for controlling a projection device that projects an image onto a projection surface, comprising: determining that the movement of the projection device has stopped when a parameter value indicating the movement of the projection device continues to be less than a first threshold value for a first period based on an output from a first sensor; detecting, during at least a portion of the first time period, at least one depth map indicative of a distance from the second sensor to each of a plurality of positions on the projection surface based on an output from the second sensor; determining an orientation of the projection device relative to the projection surface based on the at least one depth map; correcting distortion of the image based on the orientation when it is determined that the movement has stopped; A control method comprising:

2. A method for controlling a projection device that projects an image onto a projection surface, comprising: receiving an instruction to correct the distortion of the image via an operation device that operates the projection device; detecting at least one depth map based on output from the sensor, the depth map indicating a distance from the sensor to each of a plurality of locations on the projection surface; determining an orientation of the projection device relative to the projection surface based on the at least one depth map detected during at least a second time period from a first time point when the instruction is received to a second time point prior to the first time point; correcting distortion of the image based on the orientation when the instruction is received via the operation device; A control method comprising:

3. The control method of claim 1 , further comprising: calculating, during at least a portion of the first time period, a correction value for correcting distortion of the image based on detection results of the at least one depth map.

4. Detecting the at least one depth map includes: The control method of claim 1 , wherein the control method starts from the first time that the parameter value is determined to be less than the first threshold value.

5. receiving an instruction to correct the distortion of the image via an operation device that operates the projection device, and correcting the distortion of the image based on the orientation when it is determined that the movement has stopped; The control method according to claim 1 .

6. The control method according to claim 5 , wherein the timing of correcting the distortion of the image is synchronized with the timing of receiving an instruction to correct the distortion of the image via an operation device that operates the projection apparatus.

7. updating, when first data based on an output from the second sensor prior to the first period is stored in a memory, the first data to second data based on an output from the second sensor during at least a portion of the first period; detecting the at least one depth map includes detecting the at least one depth map based on the second data. The control method according to claim 1 .

8. A projection device that projects an image onto a projection surface, the projection device comprising one or more processors, the one or more processors: determining that the movement of the projection device has stopped when a state in which a parameter value indicating the movement of the projection device is less than a first threshold value continues for the first period based on an output from a first sensor; detecting, during at least a portion of the first time period, at least one depth map indicative of a distance from the second sensor to each of a plurality of positions on the projection surface based on an output from the second sensor; determining an orientation of the projection device relative to the projection surface based on the at least one depth map; correcting distortion of the image based on the orientation when it is determined that the movement has stopped; A projection device that performs the above.

Images