Projection device, projection system, projection method and program

Abstract

To provide a projection device, a projection system, a projection method and a program, capable of projecting a bright image.SOLUTION: A projection device 120 comprises: an optical modulation element 122 including a diffraction optical element emitting incident light L1 as light L2 serving as preset pattern light using optical diffraction phenomenon; and a display element 123 emitting, on the basis of the pattern light (light L2), image light L3 for projecting projection image D onto a sub-area of a projection area S. For the diffraction optical element (optical modulation element 122), the pattern light (light L2) is set so as to intensively emit the incident light L1 onto an incident area Dt of the display element 123 corresponding to the sub-region of the projection area S.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Conventionally, projection methods have been disclosed that use a projection device to project images related to work such as work procedures using a projection device to assist in work such as assembly work in a manufacturing factory, etc., to ensure that the work progresses smoothly. For example, Patent Document 1 discloses a projection system that includes a stereo camera, a control device, and a projector. This projection system recognizes the positions of work objects, tools, etc. in a work area based on images captured by the stereo camera, and projects images related to the work in accordance with the positions of the work objects, tools, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-98451 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, a projector uses almost all of the light source light within the projectable range (projection area) to project an image of uniform brightness. Therefore, in the above-mentioned application, if the entire work area is used as the projection area and an image is projected onto only a portion of it, the light source light corresponding to areas other than the area where the image is projected will not be used and will be turned off. Therefore, the projected image may be dark compared to the brightness of the light source light.

[0005] In view of the above, an object of the present invention is to provide a projection device, a projection system, a projection method, and a program that can project a bright image. [Means for solving the problem]

[0006] The projection device of the present invention comprises a diffractive optical element that utilizes the diffraction phenomenon of light to emit incident light as a set pattern light, and a display element that emits image light for projecting a projection image onto a partial region of a projection area based on the pattern light, and the diffractive optical element is set to concentrate and emit the incident light onto an incident region on the display element that corresponds to the partial region of the projection area. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a projection device, a projection system, a projection method, and a program that can project an image brightly. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the state of a work area as viewed from the side of a belt conveyor arranged in the work area. [Figure 2] FIG. 1 is a schematic diagram showing a state of a workplace including workers, with a belt conveyor arranged in the workplace viewed from above. [Figure 3] 1 is a block diagram showing a configuration of a projection system according to an embodiment of the present invention. [Figure 4] 1A and 1B are diagrams schematically illustrating the configuration and light state of a projection device of a projection system according to an embodiment of the present invention. [Figure 5] FIG. 4 is a flow diagram illustrating the operation of the projection system according to the embodiment of the present invention. [Figure 6] 1 shows images captured by an imaging device of a projection system according to an embodiment of the present invention, where (a) shows an image captured when the work object is located at the first step, and (b) shows an image captured when the work object is located at the second step. [Figure 7] 1A and 1B are diagrams schematically illustrating the configuration and the state of light when keystone correction is taken into account in a projection device of a projection system according to an embodiment of the present invention. [Figure 8] FIG. 10 is a flowchart showing the operation of the projection system according to the embodiment of the present invention, taking into account keystone correction. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described. FIGS. 1 and 2 schematically show a workplace where assembly work is performed in a manufacturing factory. A long belt conveyor 150 is installed in the workplace, extending horizontally in the drawing. The assembly work includes three steps. In the first step, for example, at position C1 on the belt conveyor 150, which is to the left of position C2 (described later), a worker P checks whether a work object X placed on the upper surface of the belt conveyor 150 has any problems, such as damage, based on a work guide. If the worker P determines that a work object X has a problem as a result of the check, the worker P removes the work object X from the belt conveyor 150. In the second step, the worker P adheres a component A to the work object X, which has been moved to position C2, approximately the center of the belt conveyor 150, after the first step, based on the work guide. In the third step, the worker P checks whether the completed work object X functions properly based on the work guide, based on the work guide, at position C3 on the belt conveyor 150, which is to the right of position C2. As a result of the verification, the worker P removes the work object X that is determined to be problematic from the belt conveyor 150, and leaves the work object X that is determined to be problem-free on the belt conveyor 150, and the belt conveyor 150 moves the work object X to the position for the next process. Here, when the work of the first process is completed, the belt conveyor 150 starts, and the work object X moves to position C2 to the right of position C1, and the belt conveyor 150 stops. The worker P who performed the first process at position C1 moves from position C1 to position C2 when the first process is completed. Similarly, when the work of the second process is completed, the work object X and the worker P move from position C2 to position C3. When the work of the third process is completed, the worker P moves from position C3 to position C1 and performs the first to third processes again. Note that the worker P for the first, second, and third processes does not have to be the same worker P. In this case, the first step, the second step, and the third step may each be a plurality of different work steps, each performed by a different worker according to the instructions of the work guide corresponding to each work step, or the first step, the second step, and the third step may each be the same work step but may each be a plurality of work steps, each performed by a different worker according to the instructions of the same work guide corresponding to each work step.

[0010] As shown in FIG. 1, an imaging device 110 is provided above the belt conveyor 150. A projection device 120 is provided adjacent to the imaging device 110 on the right side thereof. As shown in FIG. 2, the range of length W1 and width W2 on the upper surface of the belt conveyor 150 is defined as a work area W where the first, second, and third processes are performed. The total length of the belt conveyor 150 may be length W1 or may be longer than length W1. The range enclosed by a long rectangle indicated by a dashed line within the work area W is defined as a recognition area N. Furthermore, the range enclosed by a long rectangle indicated by a dashed line within the recognition area N is defined as a projection area S, which is the range within which the projection device 120 can project. Therefore, the entire projection area S is an area that can be imaged and recognized by the imaging device 110. Here, for convenience, the upper and lower sides of the projection area S are defined as sides E1 and E2, respectively. The projection area S may have the same dimensions and be located at the same position as the recognition area N.

[0011] The work area W is the area where work on the work object X (work related to the first to third steps) is performed. The recognition area N is the area that can be imaged by the imaging device 110. As will be described in detail later, the work object X is recognized based on an image captured by the imaging device 110 of the recognition area N. The projection area S is the area that can be projected by the projection device 120. The projection image D, which serves as a work guide image projected by the projection device 120, is projected onto a partial area of ​​the projection area S. Therefore, the total area of ​​the simultaneously projected projection images D is smaller than the area of ​​the projection area S. The projection image D is projected onto the upper surface of the belt conveyor 150. Here, the side of the projection image D corresponding to the upper side E1 of the projection area S is defined as upper side E3, and the side of the projection image D corresponding to the lower side E2 of the projection area S is defined as lower side E4.

[0012] The projection system 100 has a work area W where a work object X is placed, an imaging device 110, and a projection device 120. Furthermore, as shown in FIG. 3, the projection system 100 has a projection control device 200. The projection control device 200 includes a control unit 210, a storage unit 220, an operation input unit 230, and an output unit 240. The projection control device 200 can be configured, for example, by a PC (personal computer). The projection control device 200 and the imaging device 110 are electrically connected to each other and can exchange signals as needed, and the projection control device 200 and the projection device 120 are electrically connected to each other and can exchange signals as needed.

[0013] The control unit 210 is configured with at least one processor, such as a CPU (Central Processing Unit), and reads out control programs stored in the storage unit 220 to execute various processes. The control unit 210 controls at least the imaging device 110 and the projection device 120. The storage unit 220 is configured with at least one memory, such as a flash memory, an EEPROM (Electrically Erasable Programmable Read-Only Memory), or a storage device such as an SSD (Solid State Drive), for example.

[0014] The operation input unit 230 includes a user interface such as a keyboard and a mouse, and receives operation input from the user. The output unit 240 outputs a display screen such as a setting screen to a display. The output unit 240 may include output devices such as a speaker and a printer in addition to a display.

[0015] The projection device 120 includes a light source device 121, an optical modulation element 122, a display element 123, and a projection optical system 124. Note that the projection device 120 may be provided with a control device that controls the projection device 120, and the control unit 210 of the projection control device 200 may be configured to control the projection device 120 by controlling the control device of the projection device 120, or the projection device 120 and the projection control device 200 may be configured integrally.

[0016] 3 and 4, the light source device 121 is configured to be able to emit source light L1. The light source device 121 can be configured to include, for example, one or more laser diodes (LDs) and collimator lenses corresponding to each laser diode. Therefore, in the case of multiple light sources, the source light L1 from each light source is incident on an incident region Dt (described later) with the same dimensions and shape. Alternatively, the light source device 121 can be configured to include a multi-chip package (MCP) structure including laser diodes that emit light in the red, green, and blue wavelength bands. In this case, a collimator lens may also be included so that the diffused source light L1 can be incident on the optical modulation element 122 in parallel.

[0017] The optical modulation element 122 includes a diffractive optical element (DOE) that uses the diffraction phenomenon of light to shape the light source light L1 incident from the light source device 121 into light L2 (pattern light) with a desired set pattern and emits the light. The optical modulation element 122 is configured to condense and irradiate the light L2 only on an incident region Dt, which is an incident region of the light L2 on the display element 123 corresponding to the case where a rectangular incident region Dt (described later) corresponding to the case where a projection image D is projected on the projection area S, and which has an area smaller than the area of ​​an incident region B of the light L2 on the display element 123 corresponding to the case where a projection image D is projected on the projection area S, so that the brightness per unit area of ​​the light exiting the exit surface and incident on the display element 123 is greater than the brightness per unit area of ​​the light incident on the entrance surface. Here, the side of the incident region Dt corresponding to the upper side E3 of the projection image D is defined as an upper side E5, and the side of the incident region Dt corresponding to the lower side E4 of the projection image D is defined as a lower side E6. The diffractive optical element of the optical modulation element 122 may be formed, for example, using liquid crystal and be electrically controllable, or may be configured to have a refracting unevenness pattern formed on its surface so that the light is concentrated on an incident region Dt at a desired position on the display element 123. Thus, the optical modulation element 122 is capable of emitting light L2 having a pattern according to set parameters. Here, in the comparative example projection device, since the optical modulation element 122 is not present, of the light L2' incident from the light source device 121 onto almost the entire area of ​​the display element 123, light that is incident on a partial region Dt of the display element 123 corresponding to the projection image D is emitted from the display element 123, while light that is incident on other regions of the display element 123 that do not correspond to the projection image D is absorbed or reflected by the display element 123 and is not used as image light L3, which will be described later. Therefore, the brightness per unit area of ​​the projection light L4 projected onto the projection image D is substantially the same as the brightness per unit area of ​​the projection light projected onto the entire projection area S, resulting in low utilization efficiency of the source light L1. In contrast, in the projection device 120 of this embodiment, the optical modulation element 122 is optically designed to focus the emitted light L2 only on the incident region Dt.Therefore, the projection device 120 can increase the brightness per unit area in the region where the projection image D is projected compared to the projection device of the comparative example. In this embodiment, one optical modulation element 122 causes light L2 to be incident on a plurality of incident regions corresponding to a plurality of projection images (D1, D2, D3) on one display element 123 in a mutually separated and concentrated manner, but multiple optical modulation elements 122 may be configured to produce the same effect as above.

[0018] The display element 123 may be a DMD (Digital Micromirror Device) or a liquid crystal display element. The light L2 emitted from the optical modulation element 122 is irradiated onto an image forming surface 123a of the display element 123. When the light L2 is irradiated onto the image forming surface 123a, the display element 123 generates and emits a projection image (image light L3). The display element 123 is controlled by the control unit 210 to generate an image related to a task stored in the memory unit 220. The image light L3 generated and emitted by the display element 123 is incident on the projection optical system 124. The incident position of the light L2 on the display element 123 is set in advance with an aspect ratio that corresponds to the aspect ratio of the projection image D.

[0019] The projection optical system 124 can be configured, for example, with a fixed lens group and a movable lens group housed in a lens barrel. The projection optical system 124 can be zoom-adjustable by moving the lenses using a lens motor provided in the movable lens group. Image light L3 incident on the projection optical system 124 is emitted as projection light L4 from a projection opening 124a of the projection optical system 124 and projected as a projection image D (D1, D2, D3) onto the upper surface of the belt conveyor 150. In this way, the projection optical system 124 projects the projection image generated by the display element 123.

[0020] In addition, the projection device 120 may be provided with optical elements such as a diffuser plate, a microlens array, and a lens on the optical path as required.

[0021] The operation of the projection system 100 will be described with reference to Fig. 5. Fig. 5 shows the processing of the projection system 100 divided into events, the image capture device 110, the projection control device 200 (control unit 210), and the projection device 120.

[0022] Step S100: The start of the operation flow can be triggered, for example, by a worker P pressing a completion button (not shown) after completing the placement of the work object X on the belt conveyor 150, or by a sensor or the like installed at position C1 of the belt conveyor 150 detecting the completion of the placement of the work object X. Step S110: The control unit 210 of the projection control device 200 acquires imaging parameters. The imaging parameters acquired in this step are, for example, acquired by the control unit 210 by calling up imaging parameters (shutter speed, exposure time, aperture value, etc.) stored in the storage unit 220 for controlling the imaging device 110. Step S120: Control unit 210 causes imaging device 110 to capture an image including work object X. Imaging by imaging device 110 is performed on recognition area N including work object X. Step S130: Data of the captured image captured by the imaging device 110 in step S120 is sent to the projection control device 200. The control unit 210 analyzes the data of this captured image and recognizes the work object X. Recognition of the work object X includes the size, color, and arrangement (for example, the position relative to the coordinate system set within the recognition area N) of the work object X. If the work object X can be recognized, the determination result is set to "Y" and the process proceeds to step S150. If the work object X cannot be recognized, the determination result is set to "N" and the process proceeds to step S140. Step S140: If the control unit 210 cannot recognize the work object X, it changes the imaging parameters and again images the recognition area N including the work object X (step S120). The imaging of the recognition area N including the work object X is continued until the work object X is recognized.

[0023] Step S150: If the work object X can be recognized, the control unit 210 determines the progress of the work process for the work object X based on the captured image of the recognized work object X, and creates parameters for the optical modulation element 122 to project a work guide for the appropriate next process. For example, the control unit 210 creates parameters for the optical modulation element 122 to set an incident region Dt for the display element 123 so that a projection image D (D1) is projected to the upper right of the work object X at position C1, as shown in FIG. 2. In other words, the control unit 210 sets the optical modulation element 122 based on the captured image. In step S160, the control unit 210 controls the optical modulation element 122 in accordance with the parameters created in step S150. For example, as shown in FIG. 4 and an enclosed diagram Q2 in which the display element 123 is viewed from the Q1 direction in FIG. 4, the control unit 210 controls the optical modulation element 122 so that the light source light L1 incident on the optical modulation element 122 is concentrated as light L2 onto a position indicated by a rectangular incident region Dt on the image forming surface 123a of the display element 123, which corresponds to the shape of the projected image D. Note that the control unit 210 may also control the optical modulation element 122 to select an optical modulation element 122 having a pattern of recesses and projections for refraction formed on its surface from a plurality of optical modulation elements 122 having different recess and projection patterns, depending on the shape and dimensions of the incident region Dt. In step S170, if the work object X can be recognized, image data corresponding to the position of the work object X can be selected. The storage unit 220 stores a plurality of image data relating to the work indicating the contents of the work procedure manual corresponding to each work process, and the control unit 210 can read out the appropriate image data of the work procedure manual from the storage unit 220 according to the recognition result of the work object X (i.e., the position of the work object X on the belt conveyor 150 and whether the work process corresponding to the position has been performed). Note that steps S150 and S170 may be performed in reverse order. Step S180: The control unit 210 outputs a video signal for generating a projection image (image light L3) to the display element 123 based on the parameters for the optical modulation element 122 created in step S150 and the image data read out according to step S170. Step S190: When the display element 123 is controlled in step S180, the control unit 210 causes the light source device 121 to emit source light L1. When the light source device 121 emits the source light L1, the optical modulation element 122 shapes the source light L1, and light L2 is emitted from the optical modulation element 122. The light L2 is irradiated onto the position of the incident region Dt on the image forming surface 123a of the display element 123. Then, image light L3 is generated by the image forming surface 123a of the display element 123 and emitted from the display element 123. The image light L3 emitted from the display element 123 is projected as projection light L4 via the projection optical system 124 onto a predetermined position, i.e., the position of a projection image D (e.g., D1). It is preferable to create parameters for the optical modulation element 122 so that the projection position of the projection image D is a position that does not overlap with the work object X and is near the work object X.

[0024] Step S200: After the projection is started in step S190, and a predetermined time has elapsed, the control unit 210 causes the imaging device 110 to capture an image of the recognition area N including the work object X again. Here, the predetermined time after the start of projection, which is the timing for capturing an image again, is set in advance taking into account the time required for the work process. Step S210: The captured image captured in step S200 is transmitted to the projection control device 200, and first, the control unit 210 determines whether or not the work object X can be recognized from this captured image. Recognition of the work object X is performed in the same manner as the recognition of the work object X in step S130. If the work object X cannot be recognized, it is determined that the work object X has moved to position C2, and the first work step corresponding to the work guide of the projection image D1 in the projection system 100 is deemed to have been completed, and the projection of the projection image D1 is terminated (step S220). If the work object X can be recognized on the belt conveyor 150 from the captured image taken in step S200, the control unit 210 compares the previous captured image (first captured image) with the current captured image (second captured image) to determine whether there is a difference. For example, if the previous captured image (first captured image) is the captured image G1 of FIG. 6(a) captured in step S120 and the current captured image (second captured image) is the captured image G2 of FIG. 6(b) captured in step S200, the positions of the work object X are different, and therefore it is determined that there is a difference. In other words, it is determined that the work object X has moved from position C1 in the first process to position C2 in the second process, or from position C2 in the second process to position C3 in the third process. If so, the operation of the projection system 100 is determined to be "Y1 difference exists," and the process returns to step S150. If the current parameters are the parameters of the projection image D1 for the work process guide of the first process, they are reset and then parameters of the projection image D2 for the work process guide of the second process are created. If the current parameters are the parameters of the projection image D2 for the work process guide of the second process, they are reset and then parameters of the projection image D3 for the work process guide of the third process are created, and steps S160 to S190 are then executed. Here, the selection of image data in step S170 is based on the difference between the captured images (the first captured image and the second captured image), so it can be determined that it is the second process or the third process, and therefore an image of the work procedure manual for the next process, the second process or the third process, is selected depending on the current parameters. Therefore, as shown in Figure 2, the projected image D (D2) of the work procedure manual for the second process is projected to the upper right of the work object X at the C2 position, or the projected image D (D3) of the work procedure manual for the third process is projected to the upper right of the work object X at the C3 position. Furthermore, for example, if the previous captured image (first captured image) and the current captured image (second captured image) are both captured image G2 captured in step S200, it is determined that there is no difference ("no Y2 difference"). That is, it is determined that the work of the process corresponding to the current parameters is continuing. In this case, the operation flow of the projection system 100 returns to step S190, and the projection of the projection image D corresponding to the current parameters continues. Note that when the above-mentioned first process, second process, and third process are performed simultaneously by different workers, a single optical modulation element 122 is set so that different light L2 is projected onto three incident regions Dt of the image forming surface 123a of the display element 123 corresponding to the first process, second process, and third process, respectively, and thereby, a plurality of projection images (D1, D2, D3) can be projected simultaneously. In this case, steps S200 and S210 are omitted, and during step S190, when it is determined that the first, second, and third steps for the multiple work objects X flowing one after another on the belt conveyor 150 have all been completed, the belt conveyor 150 stops transporting, and the imaging device 110, projection device 120, and projection control device 200 are stopped.

[0025] The above-described projection device 120 comprises an optical modulation element 122 including a diffractive optical element that utilizes the diffraction phenomenon of light to emit incident light L1 as light L2 as a set pattern light, and a display element 123 that emits image light L3 for projecting a projection image D onto a partial region of a projection area S based on the pattern light (light L2), and the diffractive optical element (optical modulation element 122) is set to emit the pattern light (light L2) so as to concentrate the incident light L1 onto an incident region Dt on the display element 123 that corresponds to the partial region of the projection area S. Furthermore, the projection system 100 comprises the above-described projection device 120, an imaging device 110 that images an object such as a work object X, and a projection control device 200 that outputs a video signal to the projection device 120 to generate a projection image D based on image data corresponding to the image captured by the imaging device 110. The projection method involves a diffractive optical element (optical modulation element 122) that utilizes the diffraction phenomenon of light to emit incident light L1 as a set pattern light (light L2), which then emits the pattern light (light L2) that concentrates the incident light onto an incident area Dt that corresponds to a partial area of ​​the projection area S on the display element 123, and the display element 123 emits image light L3 for projecting a projection image D onto a partial area of ​​the projection area S based on the pattern light (light L2). Furthermore, the program stored in the memory unit 220 of the projection control device 200 causes the control unit 210 of the projection control device 200, which is a computer, to execute processing in which the diffractive optical element (optical modulation element 122), which utilizes the diffraction phenomenon of light to emit incident light L1 as a set pattern light (light L2), emits the pattern light (light L2) by concentrating the incident light L1 onto an incident area Dt on the display element 123, which corresponds to a partial area of ​​the projection area S, and the display element 123 emits image light L3 for projecting a projection image onto the partial area of ​​the projection area S based on the pattern light (light L2). This allows the projection device 120 to project the projection image D using almost all of the light from the source light L1, preventing off-light from occurring and thereby improving light utilization efficiency, making it possible to project bright images related to work while reducing power consumption and improving work efficiency.Furthermore, by setting the parameters of the optical modulation element 122, the position of the projection image D can be set arbitrarily within the range of the projection area S, so that the projection image D can be projected near the work object X and at a position that is easy to see without overlapping with the work object X.

[0026] Furthermore, in projection system 100, imaging device 110 captures a previous captured image (first captured image) and a current captured image (second captured image) after capturing the first captured image, and projection control device 200 outputs a video signal to projection device 120 based on image data corresponding to the difference between the first captured image and the second captured image. This makes it possible to change the projection position as work object X moves, project at a position appropriate for each process, and further to select and project an image appropriate for that process from multiple work-related images based on the difference.

[0027] Furthermore, in the projection system 100, the diffractive optical element (optical modulation element 122) is set so that the projection device 120 projects the projection image D in a position near the work object X (target) but not overlapping the target. This allows the user to perform work on the target while looking at a work procedure manual or the like.

[0028] Furthermore, the projection device 120 of the projection system 100 can perform keystone correction for the projection image D when projecting it by including keystone correction for the projection image D in the settings of the optical modulation element 122. If the projection device 120 is installed directly above the belt conveyor 150, the projection position of the projection image D may be located in the shadow of the worker. Therefore, it is conceivable that the projection device 120 is installed in a position where it projects obliquely with respect to the belt conveyor 150. In this case, the projection image can be projected into a rectangle by performing keystone correction.

[0029] Keystone correction in the projection device 120 can be performed by setting the optical modulation element 122. As shown in FIG. 7 , by creating and setting parameters for the optical modulation element 122 taking into account the installation position of the projection device 120 (projection angle information of the projection device 120), the light L2 emitted from the optical modulation element 122 and irradiated onto the image forming surface 123a of the display element 123 is shaped with keystone correction taken into account. If the upper edge E1 of the projection area S is relatively far from the projection aperture 124a of the projection optical system 124 and the lower edge E2 of the projection area S is relatively close, even if the incident area Du of the display element 123 is rectangular, the projected image D will be an inverted trapezoid with the upper edge E3 longer than the lower edge E4. This not only impairs display quality but also results in uneven brightness of the projected image. In the keystone correction of this embodiment, for example, light L2 shaped from the light source light L1 is irradiated onto the image forming surface 123a of the display element 123 as shown in the trapezoidal incident area Du in the enclosed diagram Q4 viewed from the direction Q3 in FIG. 7 . Here, the side of the incident area Du corresponding to the upper side E3 of the projected image D is defined as upper side E7, and the side of the incident area Du corresponding to the lower side E4 of the projected image D is defined as lower side E8. In this way, the projected image D can be projected after being subjected to keystone correction, and therefore can be projected onto the belt conveyor 150 in a rectangular shape.

[0030] An operation flow of the projection system 100 including keystone correction is shown in Fig. 8. The flow diagram of Fig. 8 is obtained by adding step S145 to the flow diagram of Fig. 5. That is, in step S150, parameters for the optical modulation element 122 are created, and at that time, as shown in step 145, projection angle information of the projection device 120 is obtained from the projection device 120. Then, it is possible to calculate how much keystone correction is required to project a rectangular image, and the result can be taken into account to create parameters for the optical modulation element 122. The projection angle information can be stored in advance in the storage unit 220 according to the installation position of the projection device 120.

[0031] That is, when correcting the shape of the projection image D, the diffractive optical element (optical modulation element 122) is set to change the shape of the incident region Du of the display element 123 in accordance with the correction. The diffractive optical element (optical modulation element 122) is also set to increase the brightness per unit area of ​​an expanding portion of the projection image D in accordance with the degree of expansion, or to decrease the brightness per unit area of ​​a contracting portion in accordance with the degree of contraction, in accordance with the correction. In this way, corrections such as keystone correction that can project a uniform brightness can be achieved.

[0032] In a typical projector, when keystone correction is performed, a portion of the image is optically stretched or reduced based on image data that originally has the same pixel density on the upper side (the pixel density on the upper side E3 in this embodiment) and the same pixel density on the lower side (the pixel density on the lower side E4 in this embodiment) to adjust the internal angles of the shape of the projected image D so that they all appear equal (90°). Therefore, the brightness per unit area of ​​the wider side (here, the upper side E3 side), which is relatively longer than the narrower side (here, the lower side E4 side), becomes darker than the brightness per unit area of ​​the narrower side, resulting in a gradient in the brightness of the entire projected image, which can cause uneven brightness. Furthermore, because a portion of the light source light L1 is not used, the projected image is darker than when all of the light source light L1 is used. However, according to the above-described projection system 100, projection device 120, projection method, and program, by creating parameters for setting the optical modulation element 122 including keystone correction and using light L2 from the optical modulation element 122 that includes keystone correction, a bright and uniform projected image can be obtained even with keystone-corrected image light L3. In other words, when attempting to project a trapezoidally corrected projection image D with uniform monochrome brightness based on the trapezoidal entrance area Du in Figure 7, the optical modulation element 122 must relatively lower the brightness per unit area of ​​the light projected as projection image D onto part of the projection area S by partially extending the original projection image D, and by making the brightness per unit area of ​​the narrow side (here the upper side E7 side) of the trapezoidal entrance area Du on the display element 123 greater than the brightness per unit area of ​​the wide side (here the lower side E8 side) of the trapezoidal entrance area Du, the lengths of the two opposing sides (here the upper and lower sides) in the resulting projection image D will appear to be the same, and the brightness per unit area of ​​the entire projection image D including the two opposing sides can be made uniform.When performing shape correction in this manner, the optical modulation element 122 relatively increases the brightness per unit area of ​​the incident area Du (top side E7) in accordance with the degree of expansion of the expanding portion of the projection image D (top side E3), or relatively decreases the brightness per unit area of ​​the incident area Du (bottom side E8) in accordance with the degree of contraction of the contracting portion (bottom side E4), thereby making the brightness in the projection image D uniform by imparting a gradient to the brightness of the light incident on the display element 123.

[0033] The above-described embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments may be embodied in various other forms, and various omissions, substitutions, combinations, and modifications may be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0034] For example, the surface on which the work area W is formed may be the top surface of a work table instead of the top surface of the belt conveyor 150, eliminating the need to move the projection position of the projected image. In this case, the optical modulation element 122 may be a fixed DOE with a predetermined fine uneven pattern formed on its surface, rather than an electrically controllable DOE. Furthermore, the projected image is not limited to an image for work guidance, and may also be an image for purposes other than work guidance. In such cases, projecting only a specific portion of the projectable area can improve light utilization efficiency and eliminate imbalances in brightness of the projected image due to keystone correction. In addition, although the incident area Dt is rectangular in the embodiment, it is not limited to this and may be any other shape. Furthermore, although the incident area Du is rectangular, it is not limited to this and may be any other shape as long as it can be dimmed to achieve uniform brightness. [Explanation of symbols]

[0035] 100 projection system, 110 imaging device, 120 projection device, 121 light source device, 122 optical modulation element, 123 display element, 124 projection optical system, 200 projection control device, 210 control unit, N recognition area, S projection area, W work area, X work object, Dt, Du incident area

Claims

1. a diffractive optical element that utilizes the diffraction phenomenon of light to emit incident light as a set pattern of light; a display element that emits image light for projecting a projection image onto a partial region of a projection area based on the pattern light; Equipped with A projection device in which the diffractive optical element is configured to concentrate and emit the patterned light onto an incident region corresponding to the portion of the projection area on the display element.

2. The projection device according to claim 1 , wherein when the shape of the projected image is corrected, the diffractive optical element is set so as to change the shape of the incident area of ​​the display element in accordance with the correction.

3. The projection device according to claim 2, wherein the diffractive optical element is configured to increase the brightness per unit area of ​​an expanding portion of the projected image in accordance with the degree of expansion, or to decrease the brightness per unit area of ​​a contracting portion in accordance with the degree of contraction, in accordance with the correction.

4. The projection device according to claim 1 ; an imaging device that captures an image of a target; a projection control device that outputs to the projection device a video signal for generating a projection image based on image data corresponding to an image captured by the imaging device; A projection system comprising:

5. the imaging device captures a first captured image and a second captured image after capturing the first captured image; The projection system according to claim 4 , wherein the projection control device outputs the video signal to the projection device based on the image data corresponding to a difference between the first captured image and the second captured image.

6. 6. The projection system according to claim 4, wherein the diffractive optical element is configured so that the projection device projects the projected image near the target but not overlapping the target.

7. a diffractive optical element that utilizes the diffraction phenomenon of light to emit a set pattern of light from incident light, and emits the pattern of light that concentrates the incident light onto an incident area that corresponds to a partial area of ​​a projection area on a display element; the display element emits image light for projecting a projection image onto the partial region of the projection area based on the pattern light; Projection method.

8. a diffractive optical element that utilizes the diffraction phenomenon of light to emit a set pattern of light from incident light, and emits the pattern of light that concentrates the incident light onto an incident area that corresponds to a partial area of ​​a projection area on a display element; the display element emits image light for projecting a projection image onto the partial region of the projection area based on the pattern light; A program that causes a computer to perform a process.

Images