JP2017138776A - Interactive projector and auto-calibration execution method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interactive projector automatically adjusting brightness of a calibration image imaged according to an installation environment and being capable of accurately detecting positions of calibration marks, and auto-calibration therefor.SOLUTION: An interactive projector 100 adjusts brightness of an auto-calibration image according to an installation environment from a projection section 200, and projects the auto-calibration image. An imaging section 300 images a projection surface. A calibration execution section 620 executes auto-calibration determining correspondence among positions on a picked-up image imaged by the imaging section 300 and positions in a projection image memory based on positions of a plurality of calibration marks in the auto-calibration image imaged.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an interactive projector capable of receiving an instruction from a user's indicator on a projection surface.

  Patent Document 1 discloses an interactive projector. An interactive projector projects a projection screen onto a screen, and an image including a pointing element such as a light-emitting pen or a finger can be captured by a camera, and the position of the pointer can be detected using the captured image. It is. That is, the interactive projector recognizes that a predetermined instruction such as drawing is input to the projection screen when the tip of the indicator is in contact with the screen, and redraws the projection screen according to the instruction. . Therefore, the user can input various instructions using the projection screen as a user interface.

  Japanese Patent Application Laid-Open No. 2004-133620 proposes auto calibration (corresponding to the position of a projected image and a captured image) using an auto calibration image including a plurality of calibration marks. In auto calibration, an auto calibration image is projected from the projector, the projected auto calibration image is captured by the projector camera, and the captured image is analyzed to determine the position on the projected image and the position on the captured image. It is associated.

JP2015-159524A

  However, the inventor of the present application has found that the brightness of the captured auto-calibration image may deviate from the preferable range for image analysis depending on the influence of the installation environment of the projector. For example, when the ambient light is excessively bright, the brightness of the captured image becomes excessive, and the position of the calibration mark cannot be detected with high accuracy. As a result, it has been found that there may be a problem that the position on the projected image and the position on the captured image cannot be accurately associated.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

(1) According to one aspect of the present invention, an interactive projector is provided that can receive an instruction from a user's indicator on a projection surface. The interactive projector includes a projection unit that projects an image on the projection plane according to image data stored in a projection image memory; an imaging unit that captures the projection plane and generates a captured image; and a plurality of calibrations from the projection unit. The imaging unit causes the imaging unit to image the projection plane while projecting an auto calibration image including a calibration mark, and based on the positions of the plurality of calibration marks in the captured auto calibration image, the imaging unit A calibration execution unit capable of executing auto-calibration for determining a correspondence relationship between a position on the captured image captured by the camera and a position on the image data in the projection image memory; a position determined by the auto-calibration The captured image including the indicator imaged by the imaging unit using the correspondence relationship It comprises; based on a detection unit for detecting the indicated indication position by the indicator. The calibration execution unit adjusts the exposure of the image capturing unit so that the brightness of the auto calibration image captured by the image capturing unit is within a predetermined allowable range when the auto calibration is performed.
According to this interactive projector, by adjusting the exposure of the imaging unit, the brightness of the captured auto-calibration image can be kept within a preferable range for image analysis, and the position on the projected image and the captured image can be adjusted. It is possible to accurately associate the positions.

(2) In the interactive projector, the calibration execution unit may adjust the exposure of the imaging unit so that the highest brightness in the captured auto-calibration image is within the allowable range.
According to this configuration, since the maximum brightness in the captured auto-calibration image falls within the allowable range, the position of the calibration mark can be detected with high accuracy, and the position on the projected image and the position on the captured image can be detected. Can be accurately associated.

(3) In the interactive projector, when examining the brightness in the captured auto-calibration image, a part of the area existing on the periphery of the captured auto-calibration image is excluded, and other than the excluded area It is good also as what investigates the brightness in a center area | region.
According to this configuration, the exposure adjustment is performed so that the brightness of the central region, which is less influenced by the ambient light, falls within the allowable range. Therefore, it is possible to perform appropriate exposure adjustment.

  The present invention can be realized in various forms, for example, to realize an interactive projector, a projection system including an indicator and an interactive projector, an auto-calibration execution method thereof, and a function of those methods or apparatuses. And various forms such as a non-transitory storage medium on which the computer program is recorded.

The perspective view of a position detection system. The front view of a position detection system. The side view of a position detection system. The block diagram which shows the internal structure of a projector. Explanatory drawing which shows an example of an auto calibration image. Explanatory drawing which shows the example of the calibration mark which has improper brightness. The flowchart which shows the execution procedure of auto calibration.

  FIG. 1 is a perspective view of an interactive projection system 900 as an embodiment of the present invention. The system 900 includes an interactive projector 100, a screen plate 920 that provides an operation surface, a layered detection light irradiation unit 440 (light curtain unit), and a self-luminous indicator 70. Note that the layered detection light irradiating unit 440 is a part of the interactive projector 100, but is illustrated as a separate body in FIG. 1 for convenience of illustration. The front surface of the screen plate 920 is used as a projection screen surface (SS). The projector 100 is fixed to the front and above the screen plate 920 by a support member 910. In FIG. 1, the projection screen surface SS is arranged vertically, but the system 900 can be used with the projection screen surface SS arranged horizontally.

  The projector 100 projects a projection screen PS (Projected Screen) on the projection screen surface SS. The projection screen PS usually includes an image drawn in the projector 100. When there is no image drawn in the projector 100, light is emitted from the projector 100 to the projection screen PS, and a white image is displayed. In this specification, “projection screen surface SS” means the surface of a member on which an image is projected. The “projection screen PS” means an area of an image projected on the screen surface SS by the projector 100. Usually, the projection screen PS is projected on a part of the projection screen surface SS. The projection screen surface SS is also referred to as a “projection surface SS”.

  The self-light emitting indicator 70 is a pen-type indicator having a tip portion 71 capable of emitting light, a shaft portion 72 held by a user, and a button switch 73 provided on the shaft portion 72. For example, the tip 71 of the self-luminous indicator 70 emits infrared light. The configuration and function of the self-luminous indicator 70 will be described later. In this system 900, one or a plurality of non-luminous indicators 80 (non-luminous pens, fingers, etc.) can be used together with one or a plurality of self-luminous indicators 70.

  FIG. 2A is a front view of the interactive projection system 900, and FIG. 2B is a side view thereof. In this specification, the direction along the left and right of the projection surface SS is defined as the X direction, the direction along the top and bottom of the projection surface SS is defined as the Y direction, and the direction along the normal line of the projection surface SS is defined as the Z direction. It is defined as Also, the upper left position of the projection surface SS in FIG. 2A is the origin (0, 0) of the coordinates (X, Y). For convenience, the X direction is also referred to as “left-right direction”, the Y direction is also referred to as “up-down direction”, and the Z direction is also referred to as “front-rear direction”. Further, in the Y direction (up and down direction), a direction in which the projection screen PS exists when viewed from the projector 100 is referred to as a “down direction”. In FIG. 2B, for convenience of illustration, the range of the projection screen PS in the screen plate 920 is hatched.

  The projector 100 performs layered detection on the projection lens 210 that projects the projection screen PS on the projection surface SS, the camera 310 that captures an area of the projection screen PS, and indicators (the self-luminous indicator 70 and the non-luminous indicator 80). And a layered detection light irradiation unit 440 for irradiating the light LL (FIG. 2B). In order to detect that the non-light emitting indicator 80 is in contact with the projection screen PS (that is, the projection surface SS), the layer detection light irradiation unit 440 has a layer (or curtain shape) over the entire surface of the projection screen PS. It is an irradiation part which inject | emits the detection light LL. For example, infrared light can be used as the layered detection light LL. Here, “layer” or “curtain” means a thin space shape having a substantially uniform thickness. The distance between the projection surface SS and the layered detection light LL is set to a value in the range of 1 to 10 mm (preferably 1 to 5 mm), for example.

  The camera 310 has at least a first imaging function for receiving and imaging light in a wavelength region including the layered detection light LL (infrared light) and the wavelength of infrared light emitted from the self-luminous indicator 70. The camera 310 further has a second imaging function for receiving and imaging light including visible light, and is preferably configured to be able to switch between these two imaging functions. For example, the camera 310 has a near-infrared filter switching mechanism capable of disposing a near-infrared filter that blocks visible light and allows only near-infrared light to pass in front of or behind the lens. (Not shown) are preferably provided. As shown in FIG. 2B, the camera 310 is installed at a position separated from the projection plane SS by a distance L in the Z direction.

  The example of FIG. 2A shows a state where the interactive projection system 900 is operating in the whiteboard mode. The whiteboard mode is a mode in which the user can arbitrarily draw on the projection screen PS using the self-light emitting indicator 70 and the non-light emitting indicator 80. A projection screen PS including a tool box TB is projected on the projection surface SS. This tool box TB selects a cancel button UDB for returning processing, a pointer button PTB for selecting a mouse pointer, a pen button PEB for selecting a pen tool for drawing, and an eraser tool for erasing a drawn image. It includes an eraser button ERB and a forward / backward button FRB that advances or moves the screen forward. The user can perform a process corresponding to the button or select a tool by clicking these buttons using an indicator. Note that the mouse pointer may be selected as the default tool immediately after the system 900 is activated. In the example of FIG. 2A, after the user selects the pen tool, the tip 71 of the self-luminous indicator 70 is moved in the projection screen PS while being in contact with the projection surface SS, thereby drawing a line in the projection screen PS. The state of being done is drawn. The line drawing is performed by a projection image generation unit (described later) inside the projector 100.

  Note that the interactive projection system 900 can operate in modes other than the whiteboard mode. For example, the system 900 can also operate in a PC interactive mode in which an image of data transferred from a personal computer (not shown) via a communication line is displayed on the projection screen PS. In the PC interactive mode, for example, an image of data such as spreadsheet software is displayed, and it is possible to input, create, and correct data using various tools and icons displayed in the image. .

  FIG. 3 is a block diagram showing the internal configuration of the interactive projector 100 and the self-luminous indicator 70. The projector 100 includes a control unit 700, a projection unit 200, a projection image generation unit 500, a position detection unit 600, an imaging unit 300, a signal light transmission unit 430, and a layered detection light irradiation unit 440. Yes.

  The control unit 700 controls each unit in the projector 100. In addition, the control unit 700 determines the content of the instruction made on the projection screen PS according to the indication position of the indicator (self-luminous indicator 70 or non-luminous indicator 80) detected by the position detector 600. In addition, it instructs the projection image generation unit 500 to create or change the projection image according to the contents of the instruction.

  The projection image generation unit 500 includes a projection image memory 510 that stores the projection image, and has a function of generating a projection image projected on the projection plane SS by the projection unit 200. The projected image generation unit 500 preferably further has a function as a keystone correction unit that corrects the trapezoidal distortion of the projection screen PS (FIG. 2A).

  The projection unit 200 has a function of projecting the projection image generated by the projection image generation unit 500 onto the projection surface SS. The projection unit 200 includes a light modulation unit 220 and a light source 230 in addition to the projection lens 210 described with reference to FIG. 2B. The light modulator 220 modulates the light from the light source 230 according to the projection image data given from the projection image memory 510 to form the projection image light IML. The projection image light IML is typically color image light including three colors of visible light of RGB, and is projected on the projection surface SS by the projection lens 210. As the light source 230, various light sources such as a light emitting diode and a laser diode can be adopted in addition to a light source lamp such as an ultra-high pressure mercury lamp. Further, as the light modulation unit 220, a transmissive or reflective liquid crystal panel, a digital mirror device, or the like can be adopted, and a configuration including a plurality of light modulation units 220 for each color light may be employed.

  The signal light transmitter 430 has a function of transmitting the device signal light ASL received by the self-light emitting indicator 70. The apparatus signal light ASL is a synchronizing near-infrared light signal, and is periodically emitted from the signal light transmission unit 430 of the projector 100 to the self-luminous indicator 70. The tip light emitting unit 77 of the self-light emitting indicator 70 emits indicator signal light PSL (described later) that is near infrared light having a predetermined light emission pattern (light emission sequence) in synchronization with the device signal light ASL. In addition, the camera 310 of the imaging unit 300 executes imaging at a predetermined timing synchronized with the apparatus signal light ASL when detecting the positions of the indicators (the self-emission indicator 70 and the non-emission indicator 80).

  The imaging unit 300 includes the camera 310 described with reference to FIGS. 2A and 2B. As described above, the camera 310 has a function of receiving and imaging light in a wavelength region including the layered detection light LL and the wavelength of the infrared light emitted from the self-luminous indicator 70. In the example of FIG. 3, the layered detection light LL irradiated by the layered detection light irradiating unit 440 is reflected by the indicators (the self-emission indicator 70 and the non-emission indicator 80), and the reflected detection light RDL is received by the camera 310. The state of being captured is depicted. The camera 310 further receives and images the indicator signal light PSL which is near infrared light emitted from the tip light emitting unit 77 of the self-emission indicator 70. Imaging by the camera 310 includes a first period in which the layered detection light LL emitted from the layered detection light irradiation unit 440 is in an on state (light emission state) and a second period in which the layered detection light LL is in an off state (non-light emission state). It is executed both in the period. The position detection unit 600 determines whether each indicator included in the image is the self-emission indicator 70 or the non-emission indicator 80 by comparing the images in these two types of periods. It is possible.

  The position detection unit 600 has a function of analyzing an image captured by the camera 310 and determining an indication position of an indicator (the self-emission indicator 70 or the non-emission indicator 80). At this time, the position detection unit 600 determines whether each indicator in the image is the self-emission indicator 70 or the non-emission indicator 80 using the light emission pattern of the self-emission indicator 70. . In the present embodiment, the position detection unit 600 includes a detection unit 610 and a calibration execution unit 620. The detection unit 610 has a function of analyzing a captured image captured by the camera 310 and detecting an instruction position of the indicator. The calibration execution unit 620 has a function of executing auto-calibration (correspondence between a position on a captured image and a position on image data in the projection image memory 510) described later. The result of the auto calibration is used when the detection unit 610 detects the indication position of the indicator. That is, when an instruction using the indicator 70 is performed as illustrated in FIG. 2A, the detection unit 610 uses the position correspondence determined by auto-calibration, and the instruction captured by the camera 310 of the imaging unit 300. Based on the captured image including the body 70, the indicated position indicated by the indicator 70 is detected. As a result of this auto-calibration, the correspondence between the position on the captured image and the position on the image data in the projection image memory 510 is determined. This correspondence also corresponds to the correspondence between the position on the projection surface SS and the coordinates of the projector 100.

  In addition to the button switch 73, the self light emitting indicator 70 is provided with a signal light receiving unit 74, a control unit 75, a tip switch 76, and a tip light emitting unit 77. The signal light receiver 74 has a function of receiving the device signal light ASL emitted from the signal light transmitter 430 of the projector 100. The tip switch 76 is a switch that is turned on when the tip 71 of the self-luminous indicator 70 is pressed and turned off when the tip 71 is released. The tip switch 76 is normally in an off state, and when the tip 71 of the self-luminous indicator 70 comes into contact with the projection surface SS, the tip switch 76 is turned on by the contact pressure. When the tip switch 76 is in the OFF state, the control unit 75 has the first light emission pattern by causing the tip light emitting unit 77 to emit light with a specific first light emission pattern indicating that the tip switch 76 is in the OFF state. The indicator signal light PSL is emitted. On the other hand, when the tip switch 76 is turned on, the control unit 75 causes the tip light emitting unit 77 to emit light with a specific second light emission pattern indicating that the tip switch 76 is turned on. The indicator signal light PSL having Since the first light emission pattern and the second light emission pattern are different from each other, the position detection unit 600 identifies whether the tip switch 76 is in the on state or the off state by analyzing the image captured by the camera 310. Is possible.

  The button switch 73 of the self-luminous indicator 70 has the same function as the tip switch 76. Accordingly, the control unit 75 causes the tip light emitting unit 77 to emit light with the second light emission pattern when the button switch 73 is pressed by the user, and uses the first light emission pattern when the button switch 73 is not pressed. The tip light emitting unit 77 emits light. In other words, the control unit 75 causes the tip light emitting unit 77 to emit light with the second light emission pattern when at least one of the tip switch 76 and the button switch 73 is on, and both the tip switch 76 and the button switch 73 are off. In this state, the tip light emitting portion 77 is caused to emit light with the first light emission pattern.

  However, a function different from the tip switch 76 may be assigned to the button switch 73. For example, when the same function as that of the right click button of the mouse is assigned to the button switch 73, when the user presses the button switch 73, a right click instruction is transmitted to the control unit 700 of the projector 100, and the instruction is received. A corresponding process is executed. As described above, when a function different from that of the tip switch 76 is assigned to the button switch 73, the tip light emitting unit 77 depends on the on / off state of the tip switch 76 and the on / off state of the button switch 73. Light is emitted with four different light emission patterns. In this case, the self-luminous indicator 70 can transmit to the projector 100 while distinguishing the four combinations of the on / off states of the tip switch 76 and the button switch 73.

Specific examples of the five types of signal light depicted in FIG. 3 are summarized as follows.
(1) Projected image light IML: Image light (visible light) projected onto the projection surface SS by the projection lens 210 in order to project the projection screen PS onto the projection surface SS.
(2) Layered detection light LL: Curtain-like near-infrared light that is irradiated over the entire surface of the projection screen PS in order to detect the indicated position of the non-light emitting indicator 80.
(3) Reflected detection light RDL: Near-red light reflected by the indicators (self-luminous indicator 70 and non-luminous indicator 80) of the near-infrared light emitted as the layered detection light LL and received by the camera 310 It is outside light.
(4) Device signal light ASL: near-infrared light periodically emitted from the signal light transmission unit 430 of the projector 100 in order to synchronize the projector 100 and the self-luminous indicator 70.
(5) Indicator signal light PSL: Near-infrared light emitted from the tip light emitting part 77 of the self-emission indicator 70 at a timing synchronized with the device signal light ASL. The light emission pattern of the indicator signal light PSL is changed according to the on / off state of the switches 73 and 76 of the self-light emission indicator 70. Further, it has a unique light emission pattern for identifying the plurality of self-light emitting indicators 70.

  FIG. 4 is an explanatory diagram showing an example of an auto calibration image ACP used for auto calibration. In this example, an auto calibration image ACP including 5 × 5 calibration marks CM is projected on the projection surface SS. As shown in an enlarged view in the lower part of FIG. 4, one calibration mark CM has a shape in which a plurality of bright areas LA (bright rectangular parts) and a plurality of dark areas DA (dark rectangular parts) are regularly arranged. Have. In this example, the brightness of the dark area DA is the same as that of the background and is a part of the background. The center position CC of the calibration mark CM is recognized as the intersection position of the bright area LA and the dark area DA in the center. The imaging unit 300 (camera 310) can capture the auto calibration image ACP projected on the projection surface SS as a multi-tone image. In the auto-calibration image data stored in the projection image memory 510 (FIG. 3), for example, the bright area LA is an all white area, and the dark area DA is an all black area. However, when projected onto the projection surface SS, the light area LA is not an all white area and the dark area DA is not an all black area due to the light reflection / absorption characteristics of the projection surface SS and the influence of ambient light. Therefore, in the multi-gradation auto-calibration image ACP imaged by the imaging unit 300, the bright area LA has a high brightness area in which the pixel value is slightly smaller than the maximum possible value (for example, 1023 for 10 bits). Thus, the dark area DA is a low brightness area having a pixel value slightly larger than zero.

  The calibration execution unit 620 (FIG. 3) causes the imaging unit 300 to capture the auto-calibration image ACP projected on the projection unit 200, analyzes the captured auto-calibration image ACP, and performs individual calibration. The center position CC of the action mark CM is detected. On the other hand, the image data of the auto calibration image ACP is stored in the projection image memory 510, and the center position CC of the calibration mark CM in the image data is known. Therefore, the calibration execution unit 620 associates the position on the captured image captured by the imaging unit 300 with the position on the image data in the projection image memory 510 based on the analysis result of the captured auto-calibration image ACP. It is possible to determine the relationship.

  FIG. 5 is an explanatory diagram showing an example of the calibration mark CM in the auto-calibration image ACP having inappropriate brightness. In this example, the brightness of the light area LA and the dark area DA is excessively higher than in FIG. In such a calibration mark CM, since the boundary between the bright area LA and the dark area DA is unclear, it is difficult to accurately detect the center position CC of the calibration mark CM, and the accuracy of auto-calibration decreases. There is a possibility that. Therefore, the calibration execution unit 620 adjusts the exposure of the imaging unit 300 (camera 310) so that the captured auto-calibration image ACP has appropriate brightness as described below.

  FIG. 6 is a flowchart showing an execution procedure of auto calibration including exposure adjustment. This execution procedure is performed under the control of the calibration execution unit 620. In step S110, the exposure of the camera 310 of the imaging unit 300 is initialized. For example, a minimum exposure value of the camera 310 or a value close thereto can be used as the initial exposure setting value. This is because the auto-calibration image ACP to be captured has an inappropriate brightness because it is assumed that the external ambient light (for example, sunlight) is too strong and often overexposed. is there.

  In step S120, the projection unit 200 projects the auto calibration image ACP on the projection surface SS, and the imaging unit 300 captures the image. In step S130, the peripheral area of the captured auto-calibration image ACP is excluded, and only the central area is set as the lightness investigation target. This is because the surrounding area may contain a lot of noise due to the influence of ambient light. Therefore, if the brightness is obtained with respect to the entire auto-calibration image ACP including the surrounding area, the brightness suitable for exposure adjustment. This is because there is a possibility that cannot be obtained.

  In the example shown in step S130 of FIG. 6, the left and right end regions are excluded from the captured auto-calibration image ACP. Instead, the upper end region and the upper end region are excluded. And may be respectively excluded. Alternatively, the upper and lower end regions may be excluded in addition to the left and right end portions. In the example of FIG. 6, the size of the excluded left end portion and right end portion area is about 1/3 of the width of the captured auto-calibration image ACP, and the width of the remaining central region is also imaged. Although it is about 1/3 of the width of the auto calibration image ACP, the size of the area to be excluded can be set to a preferable value as appropriate. As can be understood from these explanations, when examining the brightness, a part of the area existing at the periphery of the captured auto-calibration image ACP is excluded, and the brightness in the central area other than the excluded area is examined. preferable. However, the entire captured auto-calibration image ACP may be the lightness investigation target without excluding the peripheral region.

  In step S140, the pixel value of the pixel in the investigation target area of the captured auto-calibration image ACP is examined to obtain the maximum brightness Lmax. At this time, in order to further improve the accuracy, the auto calibration image ACP may be captured a plurality of times, and the average value of the maximum brightness Lmax of the plurality of captured auto calibration images ACP may be obtained. In the present specification, “maximum brightness Lmax” does not mean the brightness of a specific color system, but means the largest pixel value among the pixel values in the investigation target area.

  In step S150, it is determined whether or not the obtained maximum brightness Lmax is within a preset allowable range. If the maximum brightness Lmax is not within the allowable range, the process proceeds to step S160, and if it is within the allowable range, the process proceeds to step S170. The allowable range of the maximum brightness Lmax can be set, for example, in a range of 80% ± 5% of the maximum possible brightness value. Here, the “maximum possible value of brightness” means the maximum value that can be taken by a pixel value of a plurality of bits. For example, when the pixel value is expressed by 10 bits, the “maximum possible brightness value” is 1023 in decimal. Note that the allowable range of the maximum brightness Lmax preferably does not include the maximum possible brightness value (for example, 1023). The reason is that when the maximum brightness Lmax of the bright area LA has reached the maximum possible value (= 1023) due to the influence of ambient light, it is not determined that it is within the allowable range. In order to accurately determine the center position CC of the calibration mark CM, the allowable range of the maximum brightness Lmax is closer to the maximum possible value than the median value of brightness (512 in decimal for a 10-bit pixel value). It is preferably set.

  If the maximum brightness Lmax is not within the allowable range, the exposure of the camera 310 is adjusted in step S160. For example, when the maximum brightness Lmax is lower than the allowable range, the exposure value of the camera 310 is increased by N1, and conversely, when the maximum brightness Lmax is higher than the allowable range, the exposure value of the camera 310 is decreased by N2. . The increased exposure width N1 is preferably set larger than the decreased exposure width N2. For example, when the exposure value is expressed by 8 bits, it is possible to set N1 = 8 and N2 = 1. Here, the reason why the increase width N1 of exposure is made larger than the decrease width N2 is that the initial exposure value in step S110 is set to a value close to the minimum exposure value of the camera 310. If the increase width N1 of exposure is larger than the decrease width N2, the maximum brightness Lmax can be brought close to the allowable range in a short time. Further, after the maximum brightness Lmax becomes higher than the allowable range, the maximum brightness Lmax can be set within an appropriate allowable range by adjusting the exposure with a smaller reduction width N2. However, the exposure adjustment method is not limited to that described above, and other various adjustment methods can be employed.

  When the exposure of the camera 310 is adjusted to an appropriate value by the processing in steps S110 to S160 described above, autocalibration is executed using the autocalibration image ACP captured at the appropriate exposure in step S170. . That is, the calibration execution unit 620 analyzes the captured auto-calibration image ACP, detects the center position CC of each calibration mark CM, and the position on the captured image captured by the imaging unit 300; The correspondence with the position on the image data in the projection image memory 510 is determined.

  As described above, in the present embodiment, the exposure of the imaging unit 300 is adjusted so that the brightness of the auto calibration image ACP captured by the imaging unit 300 is within a predetermined allowable range. The brightness of the motion image ACP can fall within a preferable range for image analysis. As a result, even when the brightness of the captured image may become inappropriate due to the influence of the installation environment of the projector 100, the position on the projection image in the projection image memory 510 and the image captured by the imaging unit 300 are captured. It is possible to accurately associate positions on the image.

・ Modification:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

・ Modification 1:
In the above embodiment, the exposure of the imaging unit 300 is adjusted so that the maximum brightness Lmax of the captured auto-calibration image ACP is within the allowable range, but other brightness values other than the maximum brightness Lmax are used. You may adjust the exposure. For example, the exposure of the imaging unit 300 may be adjusted so that the average brightness in the survey target area of the captured auto-calibration image ACP falls within the allowable range, or the bright area LA in the survey target area may be adjusted. The exposure of the imaging unit 300 may be adjusted so that the average brightness falls within the allowable range. In the latter case, whether or not each pixel belongs to the bright area LA can be determined, for example, by determining whether or not the pixel value is equal to or greater than the median value (a decimal value of 512 for a 10-bit pixel value). it can.

Modification 2
In the above embodiment, the auto calibration image ACP having the calibration mark CM in which two types of rectangular shapes of the bright area LA (white area) and the dark area DA (black area) are combined is used. As the calibration image, an image including calibration marks having various other shapes can be used. Further, the number of calibration marks can be arbitrarily set.

・ Modification 3:
Although the interactive projector using the layered detection light LL has been described in the above embodiment, the present invention can also be applied to an interactive projector that does not use the layered detection light LL. For example, the present invention can also be applied to an interactive projector that uses a plurality of captured images captured by a plurality of cameras and detects the pointing position of a pointer by a stereo camera method (triangulation). In this case, it is preferable to perform the exposure adjustment described with reference to FIG. 6 for each camera.

  The embodiments of the present invention have been described above based on some examples. However, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

  DESCRIPTION OF SYMBOLS 70 ... Self-light-emitting indicator, 71 ... Tip part, 72 ... Shaft part, 73 ... Button switch, 74 ... Signal light receiving part, 75 ... Control part, 76 ... Tip switch, 77 ... Tip light-emitting part, 80 ... Non-light-emitting instruction Body: 100 Interactive projector, 200 Projection unit, 210 Projection lens, 220 Light modulation unit, 230 Light source, 300 Imaging unit, 310 Camera, 430 Signal light transmission unit, 440 Layer detection light irradiation unit , 500 ... Projection image generation unit, 510 ... Projection image memory, 600 ... Position detection unit, 610 ... Detection unit, 620 ... Calibration execution unit, 700 ... Control unit, 900 ... Interactive projection system, 910 ... Support member, 920 ... Screen plate, ACP ... Auto calibration image, ASL ... Device signal light, CC ... Center position, CM ... Calibration DA, dark area, ERB, eraser button, FRB, forward / backward button, IML, projected image light, L, distance, LA, bright area, LL, layered detection light, PEB, pen button, PS, projected screen, PSL ... Indicator signal light, PTB ... Pointer button, RDL ... Reflection detection light, SS ... Projection plane, TB ... Tool box, UDB ... Cancel button

Claims (4)

An interactive projector capable of receiving instructions from a user's indicator on a projection surface,
A projection unit that projects an image on the projection surface in accordance with image data stored in a projection image memory;
An imaging unit that images the projection plane and generates a captured image;
Positions of the plurality of calibration marks in the captured auto-calibration image by causing the imaging unit to capture the projection plane while projecting an auto-calibration image including a plurality of calibration marks from the projection unit. A calibration execution unit capable of executing auto-calibration for determining a correspondence relationship between a position on a captured image captured by the imaging unit and a position on image data in the projection image memory;
A detection unit that detects an indication position instructed by the indicator based on a captured image including the indicator imaged by the imaging unit using the correspondence relationship of the position determined by the auto-calibration;
With
The calibration execution unit adjusts the exposure of the imaging unit so that the brightness of the auto-calibration image captured by the imaging unit is within a predetermined allowable range when the auto-calibration is performed. Interactive projector. The interactive projector according to claim 1,
The interactive execution projector, wherein the calibration execution unit adjusts the exposure of the imaging unit so that the highest brightness in the captured auto-calibration image is within the allowable range. The interactive projector according to claim 1 or 2,
The calibration execution unit excludes a part of a region existing at the periphery of the captured auto-calibration image when examining the brightness in the captured auto-calibration image, and a center other than the excluded region An interactive projector that checks the brightness in the area. An automatic calibration execution method for an interactive projector capable of receiving an instruction from a user's indicator on a projection surface,
(A) projecting an autocalibration image including a plurality of calibration marks on the projection surface in accordance with the autocalibration image data stored in the projection image memory;
(B) generating an imaged auto-calibration image by imaging the projection plane with an imaging unit;
(C) Based on the positions of the plurality of calibration marks in the captured auto-calibration image, the position on the captured image captured by the imaging unit and the position on the image data in the projection image memory Determining the correspondence between
With
The step (b) includes the step of adjusting the exposure of the image capturing unit so that the brightness of the auto calibration image captured by the image capturing unit falls within a predetermined allowable range. Execution method.

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