JP2017134730A - Projector and position detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more accurately detect the position of an indicator even when a plurality of projectors are arranged side by side and used.SOLUTION: A projector comprises: projection means that projects a video on a projection surface; imaging means that photographs the projection surface irradiated by irradiation means with detection light; and detection means that detects, from the image photographed by the imaging means, the position of an indicator on the projection surface by using a threshold for specifying the detection light reflected on the indicator. When an operation mode is a first mode, the detection means uses a first threshold having a relatively low value, and when the operation mode is a second mode, uses a second threshold having a relatively high value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technique for detecting the position of an indicator on a projection surface.

  A so-called interactive projector that detects the position of an indicator such as a pen or a finger and performs processing according to the detected position is known. Various methods for detecting the position of the indicator have been proposed. For example, Patent Document 1 describes that a position is detected by irradiating light from an apparatus and detecting light reflected by an indicator.

Japanese Patent Laying-Open No. 2015-158886

  When a plurality of projectors of Patent Document 1 are used side by side, the detection light from each projector crosses near the boundary between the two projectors, so that it is brighter than the other areas, and the position of the indicator cannot be detected correctly. There was a problem.

  In contrast, the present invention provides a technique for more accurately detecting the position of the indicator even when a plurality of projectors are used side by side.

In the present invention, a projection unit that projects an image on a projection surface, a photographing unit that photographs the projection surface irradiated with detection light from the irradiation unit, and an image captured by the photographing unit are reflected by the indicator. Detecting means for detecting the position of the indicator on the projection surface by using a threshold value for specifying the detection light, and the detecting means is provided when the operation mode is the first mode. A projector having a relatively low first threshold value and a relatively high second threshold value when the operation mode is the second mode is provided.
According to this projector, even when a plurality of projectors are used side by side, the position of the indicator can be detected more accurately.

The first mode may be an operation mode in which the projector is used alone, and the second mode may be an operation mode in which a plurality of projectors are used side by side.
According to this projector, it is possible to detect the position of the indicator more accurately even when the projector is used alone or when a plurality of projectors are used side by side.

The first threshold value is defined to be higher as the distance from the irradiating means is shorter on the projection plane, and the difference between the second threshold value and the first threshold value is the other It may be larger as the distance from the irradiation means of the projector is shorter.
According to this projector, the position of the indicator can be detected using a threshold value corresponding to the distance from the irradiation unit.

The first threshold value may be defined so as to increase as the distance from the photographing unit to the projection plane decreases.
According to this projector, the position of the indicator can be detected using a threshold value corresponding to the distance from the photographing means to the projection plane.

The irradiating means repeats a plurality of periods including a first period in which the detection light is not radiated and a second period in which the detection light is radiated, and the detecting means has the second mode when the operation mode is the second mode. In the second period, the detection light reflected by the indicator is specified using the second threshold, and in the first period, the light emitted by the indicator is specified using the first threshold. May be.
According to this projector, the position of the indicator can be accurately detected both in the first period in which the detection light is not emitted and in the second period in which the detection light is emitted.

According to another aspect of the invention, the projector projects the image on the projection surface, the step of photographing the projection surface irradiated with the detection light from the irradiating means, and the reflected image from the photographed image by the indicator. Detecting the position of the indicator on the projection plane using a threshold value for specifying the detection light, and in the step of detecting the position of the indicator, the operation mode is the first mode. In this case, the first threshold value having a relatively low value is used, and when the operation mode is the second mode, the second threshold value having a relatively high value is used to position the indicator. Provided is a detection method characterized by detecting the above.
According to this position detection method, the position of the indicator can be detected more accurately even when a plurality of projectors are used side by side.

1 is a diagram showing an outline of a projector 1 according to an embodiment. FIG. 3 is a diagram illustrating a functional configuration of the projector 1. FIG. 3 is a diagram illustrating a hardware configuration of the projector 1. The figure which shows the outline | summary of a detection light (front). The figure which shows the outline | summary of a detection light (cross section). The figure which shows the outline | summary of the position detection of a pointer. 6 is a flowchart showing an operation mode setting process of the projector. The figure which illustrates the setting screen of an operation mode. The flowchart which shows the position detection process of a pointer. The figure which illustrates the picked-up image for position detection. The figure which illustrates the picked-up image for a reference. The figure which illustrates the picked-up image for position detection after a mask process. The figure which illustrates the picked-up image for a reference after a mask process. The figure which illustrates the image shown by difference data. The figure which illustrates a standard threshold. The figure which illustrates a reference | standard threshold value in detail. The figure which illustrates the left side correction value. The figure which illustrates the left side correction value in detail. The figure which shows the outline | summary of the correction value for left side, right side, and center.

1. Configuration FIG. 1 is a diagram illustrating an outline of a projector 1 according to an embodiment. In this example, the projector 1 is a so-called short focus projector, and is installed on a wall surface serving as a projection plane SC. An image is projected below the projector 1. The projector 1 is a so-called interactive projector, and performs processing according to the position of the indicator (not shown in FIG. 1). More specifically, the projector 1 projects an image object corresponding to the locus of the position of the indicator. As the indicator, for example, a user's finger is used. A so-called laser curtain is used to detect the user's finger. A laser curtain means extending a laser beam along the projection surface SC. When the finger is brought close to the projection surface SC, the laser light is reflected by the finger. The projector images the projection plane SC with the camera and detects the position of the finger from the reflected light.

  In order to display a larger screen, a plurality of projectors 1 are used. In this example, two projectors 1 are arranged side by side. The screens projected by these two projectors 1 are adjacent to each other, and it looks as if a large horizontally long screen is projected as a whole.

  FIG. 2 is a diagram illustrating a functional configuration of the projector 1. The projector 1 includes a projection unit 11, an irradiation unit 12, a photographing unit 13, a detection unit 14, a storage unit 15, and a processing unit 16. The projection unit 11 projects an image on a projection surface (screen or wall surface). The irradiation means 12 irradiates light for detecting the position of the indicator (hereinafter referred to as “detection light”) along the projection plane. The photographing unit 13 photographs the projection plane when the detection light is irradiated from the irradiation unit 12. The detection unit 14 detects the position of the indicator from the detection light image in the image captured by the imaging unit 13. In detecting the position of the indicator, the detection unit 14 uses a threshold value for distinguishing the image of the detection light from other images. The operation mode of the detection means 14, that is, the position detection mode, includes a first mode having a relatively low threshold value (the threshold value in the first mode is an example of the first threshold value), There is a relatively high second mode (the threshold value in the second mode is an example of a second threshold value). The detection means 14 detects the position of the indicator on the projection surface in one operation mode selected from a plurality of operation modes including the first mode and the second mode. In this example, since the operation mode is suitable for using the projector 1 alone, the first mode is referred to as “single mode”, and the operation mode is suitable for using a plurality of projectors 1 side by side. The second mode is called “multi-mode”.

  The storage unit 15 stores threshold values corresponding to the single mode and the multimode. The detection unit 14 detects the position of the indicator using the threshold value stored in the storage unit 15. The processing unit 16 performs processing according to the locus of the position of the indicator detected by the detection unit 14, for example, processing for generating data indicating an image object (for example, a line corresponding to the locus) according to the locus. The projection unit 11 projects an image according to this processing.

  FIG. 3 is a diagram illustrating a hardware configuration of the projector 1. The projector 1 includes a CPU (Central Processing Unit) 100, a ROM (Read Only Memory) 101, a RAM (Random Access Memory) 102, an IF unit 104, an image processing circuit 105, a projection unit 106, an operation panel 107, a camera 108, and a light. An irradiation unit 109 is included.

  The CPU 100 is a control device that controls each unit of the projector 1. The ROM 101 is a non-volatile storage device that stores various programs and data. The ROM 101 stores a reference threshold value and a correction value, which will be described later. The RAM 102 is a volatile storage device that stores data, and functions as a work area when the CPU 100 executes processing.

  The IF unit 104 is an interface that mediates exchange of signals or data with an external device. The IF unit 104 is a terminal (for example, VGA terminal, USB terminal, wired LAN interface, S terminal, RCA terminal, HDMI (High-Definition Multimedia Interface: registered trademark) terminal) for exchanging signals or data with an external device. Microphone terminal) and a wireless LAN interface. These terminals may include a video output terminal in addition to the video input terminal. The IF unit 104 may accept input of video signals from a plurality of different video supply devices.

  The image processing circuit 105 performs predetermined image processing (eg, size change, keystone correction, etc.) on the input video signal (hereinafter referred to as “input video signal”).

  The projection unit 106 projects an image on the projection surface SC according to the video signal on which image processing has been performed. The projection unit 106 includes a light source, an optical modulator, and an optical system (all not shown). The light source includes a lamp such as a high-pressure mercury lamp, a halogen lamp, or a metal halide lamp, or a solid light source such as an LED (Light Emitting Diode) or a laser diode, and a drive circuit thereof. The optical modulator is a device that modulates light emitted from a light source according to a video signal, and includes, for example, a liquid crystal panel or a DMD (Digital Mirror Device) and a drive circuit thereof. The liquid crystal panel may be either a transmission type or a reflection type. The optical system is configured by an element that projects light modulated by the light modulator onto the projection surface SC, and includes, for example, a mirror, a lens, and a prism. A light source and a light modulator may be provided for each color component.

  The operation panel 107 is an input device for a user to input an instruction to the projector 1 and includes, for example, a keypad, buttons, or a touch panel.

  The camera 108 is a camera for specifying the position of the indicator. In this example, the projector 1 can detect a dedicated electronic pen as an indicator in addition to the user's finger. The electronic pen has a light emitter (for example, an infrared light emitting diode) provided at the pen tip, a pressure sensor, and a control circuit (all not shown). When the pressure sensor detects that the pen tip has touched an object (such as a projection surface), the control circuit causes the light emitter to emit light with a predetermined light emission pattern. The CPU 100 detects (identifies) the position of the indicator from the image captured by the camera 108. The CPU 100 can distinguish between the plurality of indicators based on, for example, a difference in light emission pattern or a difference in light emission wavelength.

  The light irradiation unit 109 emits detection light for detecting the user's finger. For example, infrared laser light is used as the detection light. The light irradiation unit 109 irradiates the laser beam in a curtain shape so as to cover the projection surface SC. The light irradiation unit 109 includes a light emitting element that emits laser light and an optical member for diffusing the laser light in a planar shape. The light irradiation unit 109 is housed in a housing independent of other elements, and communicates with the main body of the projector 1 by wire or wirelessly.

  4 and 5 are diagrams showing an outline of the detection light. FIG. 4 is a schematic view of the projection screen SC viewed from the front. The detection light L is irradiated radially from the light irradiation unit 109 and covers the projection surface SC. FIG. 5 is a schematic view of the projection plane SC viewed from the cross-sectional direction. The detection light L is irradiated along the projection surface SC at a height slightly apart (for example, several mm) from the projection surface SC. When the user's finger F approaches the projection surface SC, the detection light is reflected by the finger F. By capturing this reflected light with the camera 108, the position of the finger is detected.

  FIG. 6 is a diagram showing an outline of the position detection of the indicator. In this example, the position detection of the pointer is configured by four phases (periods) of the first to fourth phases. These four phases are repeated in order.

  The first phase (an example of the first period) is a synchronization phase. In the first phase, a synchronization signal is transmitted from a communication unit (not shown) of the projector 1. The synchronization signal is a radio signal, for example, an infrared signal. The interval between the first to fourth phases is determined in advance, and the electronic pen can specify the start timing of the first to fourth phases by receiving this synchronization signal. The electronic pen emits light in the second to fourth phases.

  The second phase (an example of the second period) is a position detection phase. In the second phase, the camera 108 images the projection plane SC. At this time, if the indicator (user's finger or electronic pen) is close to the projection surface SC, an image of the detection light reflected by the indicator appears. Further, when the electronic pen emits light, an image of the light emission is also captured.

  The third phase is an indicator determination phase. Each of the first to fourth phases is further divided into a plurality of periods. The electronic pen emits light in a predetermined pattern. When a plurality of electronic pens are used, the light emission pattern is different for each electronic pen, so it is possible to specify which electronic pen emits light. In addition, since the detection light is not irradiated from the light irradiation unit 109 in the third phase, the image of the detection light by the finger is not detected.

  The fourth phase (an example of the second period) is a position detection phase similar to the second phase. By performing position detection in the fourth phase in addition to the second phase, position detection accuracy can be improved.

  Refer to FIG. 3 again. In this example, when the CPU 100 executes a program stored in the ROM 101, the functions shown in FIG. The projection unit 106 is an example of the projection unit 11. The light irradiation unit 109 is an example of the irradiation unit 12. The camera 108 is an example of the photographing unit 13. The CPU 100 is an example of the detection unit 14 and the processing unit 16. The ROM 101 and the RAM 102 are an example of the storage unit 15.

2. Operation 2-1. Mode Setting FIG. 7 is a flowchart showing the operation mode setting process. The flow in FIG. 7 is started when, for example, the user calls the operation mode setting screen by operating the menu screen of the projector 1. In step S <b> 11, the CPU 100 accepts setting of the operation mode of the projector 1.

  FIG. 8 is a diagram illustrating an operation mode setting screen. In this example, four options “off”, “left side”, “right side”, and “center” are presented for multi-projection (display using a plurality of projectors 1). “Off” is a single mode option when the projector 1 is used alone. “Left side”, “Right side”, and “Center” are options when a plurality of projectors 1 are used in combination, that is, multimode. In the case of the multi mode, it is necessary to specify the positional relationship with other projectors 1. “Left side”, “right side”, and “center” are options when the projector 1 is located at the left end, the right end, and a position between two or more projectors, respectively. The user selects an option corresponding to the positional relationship between the projector 1 and the other projector 1 from these options. The CPU 100 stores information for specifying the selected option in the RAM 102.

2-2. Pointer Position Detection FIG. 9 is a flowchart showing the pointer position detection process. The flow in FIG. 9 is started when the power of the projector 1 is turned on, for example.

  In step S <b> 21, the CPU 100 acquires data of an image captured by the camera 108. An image captured by the camera 108 is referred to as a “captured image”. The photographed image includes a photographed image for position detection photographed in the position detection phase and a photographed image for reference photographed at a timing other than the position detection phase (for example, a synchronization phase). Hereinafter, the captured image data for position detection is referred to as “detection data”, and the captured image data for reference is referred to as “reference data”.

  10 and 11 are diagrams illustrating captured images. FIG. 10 shows a captured image for position detection, and FIG. 11 shows a captured image for reference. An area A in the figure is an area where an image is projected by the projection unit 106 (hereinafter referred to as “projection area”). Due to the positional relationship between the camera 108 and the projection surface SC, the area A is not rectangular but distorted in the captured image. In this example, the image Sb and the image Sf are shown in the shot image for position detection, and the image Sb is shown in the shot image for reference. The image Sb is an image obtained by reflecting external light such as a fluorescent lamp on the projection surface SC. Since the image Sc is unrelated to the detection light, the image Sc appears in both the position detection and reference captured images. The image Sf is an image of detection light reflected by the user's finger. The image Sf is shown only in the captured image for position detection.

  Refer to FIG. 9 again. In step S22, the CPU 100 cuts out a projection area from the captured image. Specifically, a mask process is performed on the detection data and the reference data. The mask process is a process of rewriting data in a portion other than the projection area to a predetermined gradation value (for example, a gradation value corresponding to black). If the positional relationship between the projector 1 and the projection surface SC is determined, it is also determined which part of the captured image is the projection area. For example, the projection area is specified by projecting a pattern image for calibration after the projector 1 is installed.

  12 and 13 are diagrams illustrating the captured image after the mask processing. FIG. 12 shows a captured image for position detection, and FIG. 13 shows a captured image for reference. Parts other than the projection area are masked in black. By this processing, erroneous detection outside the projection area can be suppressed.

  Refer to FIG. 9 again. In step S23, the CPU 100 subtracts the reference data from the detection data to generate difference data. Subtracting the reference data from the detection data means subtracting the gradation value of the reference data from the gradation value of the detection data for each pixel.

  FIG. 14 is a diagram illustrating an image indicated by the difference data. The difference between pixels having the same gradation value between the detection photographed image and the reference photographed image is zero, and the difference between pixels that are brighter in the detection photographed image than the reference photographed image is a positive value. . In this example, all the portions other than the image Sf have gradation values of zero, and only the image Sf remains.

  Refer to FIG. 9 again. In step S <b> 24, the CPU 100 reads the reference threshold value from the ROM 101. The reference threshold value is a threshold value used for specifying the detection light reflected by the indicator in the captured image, and is used when the influence of other projectors 1 is not taken into consideration, that is, in the single mode. It is a threshold value.

  FIG. 15 is a diagram illustrating a reference threshold value. The reference threshold value is defined according to the distance d1 (an example of the first distance) from the light irradiation unit 109 in the projection area A. Specifically, since the intensity of the reflected light becomes weaker as the position is farther from the light irradiation unit 109, the threshold value is higher as the distance d1 is shorter (closer from the light irradiation unit 109), and the distance d1 is longer (light irradiation unit). The farther from 109) the threshold is set lower. Here, in order to simplify the drawing, an example in which the projection area A is divided into three areas is shown. The threshold value of the region A1 closest to the light irradiation unit 109 is the highest, and the threshold value decreases as the distance from the region A2, the region A3 and the light irradiation unit 109 increases.

  FIG. 16 is a diagram illustrating the reference threshold in more detail. In this figure, the horizontal axis indicates the distance from the light irradiation unit 109, and the vertical axis indicates the threshold value. The reference threshold value is defined according to the distance between the projector 1 and the projection plane SC, more specifically, the distance d2 (an example of the second distance) between the camera 108 and the projection plane SC. If the projector 1 and the projection surface SC are fixed, the distance d2 is unchanged. As the projector 1 (camera 108) is farther from the projection plane SC, the intensity of reflected light received by the camera 108 becomes weaker. Therefore, the shorter the distance d2 (the closer the projector 1 and the projection plane SC are), the higher the threshold value is. The threshold value is set lower as the distance d2 is longer (as the projector 1 and the projection surface SC are farther).

  The reference threshold value in FIG. 16 is mapped to the captured image as shown in FIG. The mapping of the reference threshold value to the captured image is performed by geometric conversion for converting an ideal (rectangular) projection area into the shape of the projection area in the captured image. This geometric transformation has a correlation with the geometric transformation that makes the projection area on the projection screen SC rectangular. These geometric transformations are performed using parameters determined by projecting a calibration pattern after the projector 1 is installed and photographing it with the camera 108. The mapping of the reference threshold value to the photographed image does not change while the positional relationship between the projector 1 and the projection surface SC is fixed.

  Refer to FIG. 9 again. In step S25, the CPU 100 determines the operation mode setting. The operation mode is set according to the flow of FIG. 7, and information for determining the operation mode is stored in the RAM 102. When the operation mode is set to the single mode (S25: OFF), the CPU 100 shifts the processing to step S29. When the operation mode is set to the multi mode (left side) (S25: left), the CPU 100 shifts the process to step S26. When the operation mode is set to the multi mode (right side) (S25: right), the CPU 100 shifts the process to step S27. When the operation mode is set to the multi mode (center) (S25: center), the CPU 100 shifts the processing to step S28.

  In step S26, the CPU 100 reads the left correction value from the ROM 101, adds it to the reference threshold value, and generates a left threshold value. The threshold value for the left side is a threshold value used for specifying the detection light reflected by the indicator in the projector whose operation mode is set to the multi mode (left side).

  FIG. 17 is a diagram illustrating the left correction value. The fact that the projector 1 is located at the left end means that another projector 1 is installed on the right side of the projector 1. That is, the detection light emitted from the light irradiation unit 109 of the other projector 1 reaches the right part of the projection area of the projector 1. For example, when the finger touches the vicinity of the right end of the projection area on the projection surface SC, the finger is irradiated not only from the light irradiation unit 109 of the projector 1 but also from the light irradiation unit 109 of the other projector 1. The detection light is also hit. Therefore, the intensity of the reflected light is increased compared to the case where only one projector 1 is used, and the possibility of erroneous detection is increased. The correction value for the left side is for suppressing such erroneous detection, and the value increases as it goes to the upper right of the projection area (closer to the light irradiation unit 109 of the other projector 1) (Δth1> Δth2> Δth3).

  FIG. 18 is a diagram illustrating the left-side correction value in more detail. In this figure, the horizontal axis indicates the position in the projection area, and the vertical axis indicates the correction value. The correction value is defined for each line of the projection area, for example, but only the correction value for one line is shown here. The correction value for the left side is defined according to the distance d2 between the projector 1 (camera 108) and the projection surface SC, similarly to the reference threshold value. The shorter the distance d2, the higher the correction value, and the longer the distance d2, the lower the correction value. The correction values in FIG. 18 are mapped to the captured image. The mapping of the correction value to the captured image is performed in the same manner as the mapping of the threshold value to the captured image.

  Refer to FIG. 9 again. In step S27, the CPU 100 reads the right correction value from the ROM 101 and adds it to the reference threshold value to generate a right threshold value. In step S28, the CPU 100 reads the center correction value from the ROM 101 and adds it to the reference threshold value to generate the center threshold value. These processes are the same as those for the left correction value except that the correction value profile is different. The right-side threshold value is a threshold value used for specifying the detection light reflected by the indicator in the projector whose operation mode is set to the multi-mode (right-side), and the central threshold value is the operation threshold value. This is a threshold value used for specifying the detection light reflected by the indicator in a projector whose mode is set to multi-mode (center). Since both the reference threshold value and the correction value are unchanged while the positional relationship between the projector 1 and the projection surface SC is fixed, the corrected threshold value is calculated prior to the flow of FIG. In addition, this may be stored in the ROM 101 or the RAM 102.

  FIG. 19 is a diagram showing an outline of correction values for the left side, the right side, and the center. In these figures, the horizontal axis represents the position in the projection area, and the vertical axis represents the correction value. In the correction value for the left side, the value is higher toward the right side of the projection area. In the correction value for the right side, the value is higher toward the left side of the projection area. Since the threshold value used in the multimode is a value obtained by adding these correction values to the reference threshold value used in the single mode, the correction values are the threshold values in the multimode and the single mode. Corresponds to the difference from the threshold.

  Note that the correction of the reference threshold value is performed on images captured in the second phase and the fourth phase (position detection phase) in which the detection light is emitted from the light irradiation unit 109 among the captured images. The reference threshold value is used as it is for an image photographed in the phase (indicator determination phase).

  Refer to FIG. 9 again. In step S29, the CPU 100 binarizes the captured image. The threshold value after correction is used for binarization of the captured image. When the operation mode is the single mode, the corrected threshold value is equal to the reference threshold value. For example, the gradation value is converted to white for pixels having a gradation value higher than the threshold value, and to black for pixels having a gradation value lower than the threshold value.

  In step S30, the CPU 100 detects the position of the indicator from the binarized captured image. Specifically, the coordinates of the center of gravity of the area where the gradation value is white in the photographed image is detected as the position of the indicator.

  This completes the position detection process. Although detailed description is omitted, the CPU 100 performs processing according to the position of the indicator, for example, drawing an image object according to the locus of the position of the indicator. Further, the CPU 100 controls the projection unit 106 to project the drawn image. The CPU 100 repeatedly executes the flow of FIG. 9 at a predetermined cycle, for example.

  According to the projector 1, the threshold value for detecting the position of the indicator is corrected according to the positional relationship with the other projectors 1. Therefore, erroneous detection of the indicator due to the detection light of the other projector 1 can be suppressed.

3. Modifications The present invention is not limited to the above-described embodiments, and various modifications can be made. Hereinafter, some modifications will be described. Two or more of the following modifications may be used in combination.

  The reference threshold value correction method is not limited to that exemplified in the embodiment. For example, instead of adding the correction value to the reference threshold value, the reference threshold value may be multiplied by a correction coefficient.

  The indicator detected by the projector 1 is not limited to those exemplified in the embodiment. For example, the projector 1 may detect a pen-type indicator that reflects detection light, for example, without detecting an electronic pen.

  The processing using the detected position of the indicator is not limited to that exemplified in the embodiment. For example, an indicator may be used as a pointing device.

  In the above-described embodiment, the mode in which the two projectors 1 are arranged on the left and right and the images projected by the two projectors is arranged on the left and right has been described, but the mode in which three or more projectors 1 are arranged may be used. Moreover, the aspect which arranges a some image | video up and down by projecting an image | video in the horizontal direction from each of the some projector 1 arranged up and down may be sufficient.

  The hardware configuration of the projector 1 for realizing the functions illustrated in FIG. 2 is not limited to that illustrated in FIG. The projector 1 may have any hardware configuration as long as the required function can be realized. For example, the projector 1 may incorporate the light irradiation unit 109. Alternatively, the projector 1 may have a processor dedicated to detecting the position of the indicator.

DESCRIPTION OF SYMBOLS 1 ... Projector, 11 ... Projection means, 12 ... Irradiation means, 13 ... Imaging means, 14 ... Detection means, 15 ... Storage means, 16 ... Processing means, 100 ... CPU, 101 ... ROM, 102 ... RAM, 104 ... IF section DESCRIPTION OF SYMBOLS 105 ... Image processing circuit 106 ... Projection unit 107 ... Operation panel 108 ... Camera 109 ... Light irradiation part

Claims (6)

Projection means for projecting an image on a projection surface;
Photographing means for photographing the projection plane irradiated with the detection light from the irradiation means;
Detecting means for detecting the position of the indicator on the projection plane using a threshold value for specifying the detection light reflected by the indicator from the image photographed by the photographing means. ,
The detection means uses a first threshold value that is relatively low when the operation mode is the first mode, and a second value that is relatively high when the operation mode is the second mode. A projector characterized by using a threshold value. The projector according to claim 1, wherein the first mode is an operation mode in which the projector is used alone, and the second mode is an operation mode in which a plurality of projectors are used side by side. The first threshold value is defined to be higher as the distance from the irradiation unit is shorter on the projection plane,
The projector according to claim 2, wherein the difference between the second threshold value and the first threshold value increases as the distance from the irradiation unit included in another projector decreases. 4. The projector according to claim 1, wherein the first threshold value is defined such that the first threshold value increases as a distance from the photographing unit to the projection plane decreases. 5. The irradiation means repeats a plurality of periods including a first period in which the detection light is not irradiated and a second period in which the detection light is irradiated,
When the operation mode is the second mode, the detection unit identifies the detection light reflected by the indicator using the second threshold value in the second period, and in the first period, The projector according to claim 1, wherein light emitted from the indicator is specified using the first threshold value. A step in which the projector projects an image on a projection surface;
Photographing the projection plane irradiated with the detection light from the irradiation means;
Detecting a position of the indicator on the projection plane using a threshold value for specifying the detection light reflected by the indicator from the photographed image, and
In the step of detecting the position of the indicator, when the operation mode is the first mode, a first threshold value having a relatively low value is used, and when the operation mode is the second mode, the value is A position detection method for a pointer, wherein the position of the pointer is detected using a relatively high second threshold value.

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