JPH05233148A - Projector device with coordinate input function - Google Patents

Abstract

PURPOSE:To securely detect the coordinate position of a luminescent spot in specified light irradiated from a coordinate input means on a screen by using a back projecting type projector. CONSTITUTION:A projector 16 projects a picture from the back side of a transmission type screen 12 on the screen 12. A coordinate input means 20 irradiates prescribed light from the front side of the transmission type screen 12 on the transmission type screen 12. A video camera 18 arranged near the projector 16 takes the transmission type screen 12 from the back side of the transmission type screen 12. A coordinate detection means 28 detects the coordinate of prescribed light on the transmission type screen 12 from the output signal of the video camera 18. Since the video camera 18 takes the screen from the back side of the transmission type screen 12, a direction that the light of a displayed picture advances differs from a direction that prescribed light advances. Thus, the influence of the displayed picture as against the detection of prescribed light becomes small. Thus, the coordinate of specified light on the screen can securely be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projector device capable of inputting coordinates by a predetermined light such as a laser.

[0002]

2. Description of the Related Art A projector device for projecting an image on a large screen is a very effective device for transmitting information to many people at once. When performing various explanations using this projector device, if a specific position on the screen, that is, a coordinate position can be specified, a specific image is indicated or a specific command (when the projector device displays a computer output) is issued. It is convenient for inputting. At this time, when the coordinates are input by irradiating the screen with light such as a laser, the explainer can specify the coordinates from an arbitrary place without directly operating the computer.

A conventional example of such an apparatus is disclosed in Japanese Patent Laid-Open No. 2-3.
It is disclosed in Japanese Patent Publication No. 06294. In this conventional example,
An image is projected on this screen by a front projection type projector arranged on the front side of the reflective screen. On the other hand, a specific position on the screen is designated from the front side of the screen by the bright spot of the laser beam, and the bright point of the laser beam is detected by the video camera arranged on the front side of the screen to input coordinates. When the output signal of the video camera is processed and the coordinates are fixed, the projector displays the cursor on the screen at the coordinate position.

[0004]

In the above-mentioned prior art,
As the projector and video camera are located in front of the screen, the person operating the laser will
I was unable to stand between the projector and video camera and the screen, limiting the position of the explainer. Also,
In order for the video camera to shoot the front of the screen,
The output signal processing of the video camera for detecting the coordinates of the laser light is complicated because it is affected by outside light, for example, a display image and an interior light.

On the other hand, a rear projection type projector device has been proposed in which a projected image is not affected by outside light or an explainer.
In this, a projector is arranged on the back side of a transmissive screen and an image is projected on the back side of the screen. However, since the screen is a transmissive screen, the image can be observed from the front side of the screen. However, no coordinate input device using specific light such as a laser adapted for the rear projection type projector device has been proposed. If the technique disclosed in Japanese Patent Laid-Open No. 2-306294 is applied to a rear projection type projector device, a video camera is arranged on the front side of the screen to detect the bright spot coordinates of the laser light.
In this case, due to the nature of the transmissive screen, the laser light is also transmitted and the reflection on the screen is reduced. As a result, the contrast of the bright spots of the laser light is lowered, and it becomes easy for the influence of external light. In order to prevent the decrease in contrast, it is conceivable to increase the output power of the laser beam or to specially process the front surface of the transmissive screen, but there are problems in terms of safety and visibility of the displayed image.

Therefore, an object of the present invention is to provide a projector device with a coordinate input function which can reliably detect the coordinate position of the bright spot of the specific light emitted on the screen from the coordinate input means by using the rear projection type projector. is there.

[0007]

A projector device with a coordinate input function of the present invention includes a transmissive screen 12, a projector 16 for projecting an image from the rear side of the transmissive screen 12 onto the screen, and a transmissive screen 12. The coordinate input means 20 for irradiating the transmissive screen 12 with predetermined light from the front side and the projector are arranged in the vicinity of the projector.
A video camera 18 for photographing the transmissive screen 12 from the back side of the transmissive screen 12 and a coordinate detecting means 28 for detecting the coordinates of predetermined light on the transmissive screen 12 from the output signal of the video camera 18. I am. Since the video camera shoots the screen from the back side of the transmissive screen, the light traveling direction of the display image is different from the light traveling direction of the predetermined light, so that the display image has less influence on the detection of the predetermined light. Therefore, the coordinates of the specific light on the screen can be reliably detected.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram of a preferred embodiment of the present invention. The projector device 10 includes a cabinet 11
And a laser beam pointer 20 which is a coordinate input means for generating specific light, and a coordinate detection means 28. In the cabinet 11, a transmissive screen 12
A reflector 14, a projector (cathode ray tube and lens system) 16, and a video camera 18 are provided. The positional relationship between them is as shown in FIG. That is,
The projector 16 arranged on the back side of the screen 12
The image from is reflected by the reflector 14 and
Display the image on the back of 2. The instructor or the operator holds the laser beam pointer 20 in his hand and directs the laser beam generated from the pointer to an arbitrary position on the screen 12 to form a bright spot.

On the other hand, the lens of the video camera 18, such as a CCD (charge-coupled device) camera, is provided with an optical filter that passes only the laser beam bright spots displayed on the screen 12. Therefore, the video camera 18
Generates a video output signal corresponding to only the laser beam luminescent spot displayed on the back surface of the screen 12 via the reflector 14, and the coordinate detecting means 28 via the cable 34.
Supply to. The coordinate detecting means 28 detects the coordinates of the laser bright spot from the output signal of the video camera 34, and its specific configuration and operation will be described later.

The computer 22 has a keyboard 24 and a mouse (not shown) as input devices and a cathode ray tube monitor 26 as an output device. Also, the computer 2
The output image signal of No. 2 is supplied to the projector 16 via the cable 30. Further, the computer 22 receives the coordinate information from the coordinate detecting means 28 via the cable 32, controls the cassette on the output image, and executes various commands according to the information.

By the way, the transmissive screen 12 in the rear-projection type projector device seeks the brightness in the front direction of the screen, and the color misregistration (color ... As a shift measure, it is a lens screen with lenticular and Fresnel lenses stacked. That is, the transmissive screen 12 can be viewed as one large lens (screen lens effect). As a result, if the screen 12 is irradiated with specific light such as a laser beam from the front side of the screen 12 due to optical reversibility, the laser beam is refracted when passing through the screen 12 due to the lens effect of the screen. Then, the cathode ray tube of the projector 16 is entered. This traces back the trajectory of light as the image displayed on the cathode ray tube reaches the observer's eyes via the screen.

The position of the video camera 18 is ideally the position of the projector 16. However, in reality, the lens effect of the above-mentioned screen is not so large, so that the focus of this lens also has a certain range. Therefore, as shown in FIG. 2, the video camera 18 is arranged above the cathode ray tube of the projector 16 in a direction substantially parallel to the cathode ray tube. As a result, the bright spots of the laser beam on the screen 12 also enter the video camera 18 brightly.

FIG. 3 is a block diagram of the coordinate detecting means 28. The video signal from the video camera 18 is input to the sync separation circuit 36 and the comparator 38 via the cable 34. The sync separation circuit 36 detects a horizontal sync signal H and a vertical sync signal V from the video signal. The pixel clock generation circuit 40 generates a pixel clock signal synchronized with the horizontal synchronizing signal H. The horizontal counter 42 is cleared by the horizontal synchronizing signal H and counts the pixel clock. The vertical counter 44 is cleared by the vertical synchronizing signal V and counts the horizontal synchronizing signal H.

The comparator 38 compares the video signal and the comparison voltage from the comparison voltage generating circuit 46, and detects the time when the signal component in response to the laser beam included in the video signal is generated. Since the X latch circuit 48 latches the count value of the horizontal counter 42 according to the output signal of the comparator 38, the latched value becomes the horizontal (X) coordinate value of the laser beam. Further, since the Y latch circuit 50 latches the count value of the vertical counter 44 according to the output signal of the comparator 38, the latched value becomes the vertical (Y) coordinate value of the laser beam. The coordinate information of these latch circuits 48 and 50 is stored in the interface 52 such as RS-232C.
Is appropriately processed by the computer and transferred to the computer 22 via the cable 32.

Although the preferred embodiment of the present invention has been described above, various modifications and changes can be made without departing from the spirit of the present invention. For example, without using a reflector,
The projector and video camera may be aimed directly at the back of the screen. Also, projectors and video
The camera is arranged on the front side of the screen, but by combining a plurality of reflectors, it is possible to illuminate an image on the back side of the screen or photograph the back side.

[0016]

As described above, according to the present invention, the coordinate position of the bright spot of the specific light radiated on the screen from the coordinate input means can be reliably detected by using the rear projection type projector. Further, since the positional relationship between the screen, the video camera and the projector is fixed by the cabinet, the video camera need only be adjusted once when the camera is attached. Therefore, there is no need for readjustment even if the projector device is moved. Furthermore, since the video camera is arranged in the vicinity of the cathode ray tube of the projector, the coordinate detection area of the specific light is substantially a parallelogram. Therefore, the resolution of coordinate detection is usually limited by the short side of this parallelogram, but the present invention allows up to the number of pixels of the video camera. Further, distortion correction calculation of the output video signal of the video camera can be omitted.

[Brief description of drawings]

FIG. 1 is a block diagram of a preferred embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a transmissive screen, a projector and a video camera used in the present invention.

FIG. 3 is a block diagram of coordinate detection means used in the present invention.

[Explanation of symbols]

 12 transmissive screen 16 projector 18 video camera 20 coordinate input means 28 coordinate detection means

Claims (1)

[Claims] 1. A transmissive screen, a projector for projecting an image from the rear side of the transmissive screen onto the transmissive screen, and coordinate input for irradiating the transmissive screen with predetermined light from the front side of the transmissive screen. Means, a video camera arranged near the projector for photographing the transmissive screen from the rear side of the transmissive screen, and coordinates of the predetermined light on the transmissive screen from an output signal of the video camera. A projector device with a coordinate input function, which comprises a coordinate detection means for detecting the.