JP2008225554A - Projector system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve detection precision for a laser pointer without using an optical filter. <P>SOLUTION: The shutter speed of a photodetector 40 and a blur level of a photographed image are detected through optimization processing so as to detect a laser pointer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a projector system that projects an image, and more particularly to a projector system that projects the same image as an image displayed on a display of a computer onto the surface of an object (hereinafter referred to as a projector screen).

  Conventional projector systems can project figures, documents, etc. created by a computer such as a personal computer onto a projector screen, and thus have been used for presentations in a wide variety of places such as lectures.

  In such a projector system, when the presenter points to the projected image, a long bar must be used to point to a specific position on the projector screen. For this reason, two people, a person who operates a personal computer for turning pages of images to be projected, and a person who gives explanations are necessary for the presentation.

  In order to eliminate such problems, a portable infrared light emitting device called a laser pen is used to remotely emit laser light onto a projector screen and project it in the form of a spot (round dot) of a specific color. Thus, there has been proposed a projector system that informs the viewer of an arbitrary position on the projector screen (Patent Document 1).

  Such a conventional system configuration is shown in FIG. In FIG. 1, reference numeral 10 denotes a personal computer (hereinafter abbreviated as a personal computer) that generates an image to be controlled. The personal computer 10 has a memory (RAM) for storing image data of an image for one screen displayed on the display. This image data is luminance data and color component data (RGB data) for each pixel constituting one screen.

  The personal computer 10 is equipped with a software program for image display (hereinafter abbreviated as display software, such as word processing software and drawing software) and projector software (hereinafter abbreviated as projector software) for controlling the projector 20. ing. When the projector software is executed by the CPU in the personal computer, a projection image in the form of image data (generally called an image signal) stored in the memory is sent from the personal computer 10 to the projector 20.

  Reference numeral 20 denotes a projector having a liquid crystal display (LCD) and a light source. When light from the light source of the three primary colors (RGB) is irradiated from the back of the liquid crystal display, the open pixels among the pixels of the liquid crystal display allow light to pass through, and then the transmitted light of the three primary colors is combined. The transmitted light 50 is projected onto the projector screen 60 through the optical system. An image in the form of image data sent from a personal computer by opening and closing each pixel (three RGB pixels per pixel) of the liquid crystal display according to the above-mentioned image data and adjusting the luminance of the light sources of the three primary colors based on the image data Is projected on the projector screen 60 as a visible image.

  Reference numeral 30 denotes an optical unit that emits a laser beam 60. Generally, the name “laser pen” is widely used. Reference numeral 40 denotes a light receiver, and a light receiver having an optical sensor for one screen, for example, a light receiver called a CCD can be used. The light receiver 40 includes a filter that transmits only the reflected light 70 from the laser pen 30 and blocks the reflected light projected from the projector 20. When the reflected light 70 enters a specific pixel in the light receiving screen of the CCD of the light receiver 40, the CCD converts the incident light to the photosensor of each pixel into an electrical signal (photoelectric conversion signal) and outputs it.

  The voltage of the photoelectric conversion signal output from each pixel represents the luminance of the pixel incident light. Since the photoelectric conversion signal of each pixel is an analog signal, the A / D converter in the light receiver 40 converts the voltage into a digital signal representing a numerical value. A digital signal for one screen (hereinafter referred to as a photographed image) generated by the light receiver 40 in this way is sent to the personal computer 10. The projector software of the personal computer 10 compares the luminance value indicated by the image data of each pixel in the received photographed image with a predetermined threshold value, and detects a pixel position having a luminance value larger than the threshold value. The person who is looking at the projector screen 60 can know the position where the presenter is pointing by the irradiation image of the laser beam on the projector screen 60. Hereinafter, an irradiation image of the laser beam displayed at this position will be referred to as a laser pointer.

  In addition, when the position of the laser pointer is detected by the above-described method in the photographed image of the light receiver, the personal computer 10 handles information related to the position of the laser pointer in the same manner as a pointing device such as a mouse.

  With the projector system described above, the presenter operates the laser pen 30 while operating the personal computer 10 to not only specify an arbitrary position of the image projected on the projector screen 60 but also the positional information on the personal computer 10. Can now enter.

Japanese Patent Laid-Open No. 11-85395

  In order to reliably capture the image of the laser pointer on the projector screen with the light receiver 40, it is preferable to install an optical filter in the light receiver and guide only infrared light (laser light) to the light receiver 40. However, there is a drawback that the system becomes expensive.

  When the optical filter is not provided, the image projected from the projector 20 is also photographed by the light receiver 40 on the projector screen 60. As a result, when an image of the laser pointer is detected in the image pickup result of the light receiver, there is a problem that the detection error becomes worse.

  Therefore, an object of the present invention is to provide a projector system that improves the detection accuracy of a laser pointer without providing an optical filter.

In order to achieve such an object, the present invention projects an image on a projector screen and receives a reflected light of a laser beam irradiated as a laser pointer on the projector screen by a laser pen by a light receiver, In the projector system for detecting the designated position by the laser pen on the projector screen by converting the position of the laser pointer on the light receiving screen detected by the light receiver to the position of the laser pointer on the projector screen,
First instruction means for repeatedly instructing while changing the degree of blurring from an initial value to a final value;
Image processing means for subjecting image data of all pixels on the light receiving screen of the light receiver to a blurring process to the extent instructed by the first instruction means;
First calculation means for calculating an average value of luminance of all the image data after the blur processing is performed;
Second calculation means for calculating a difference value between the luminance of the image data of each pixel and the average value of the luminance calculated by the first calculation means;
Counting means for comparing the difference value obtained by the second calculation means with a predetermined threshold value and counting the number of image candidates of the laser beam having a difference value larger than the threshold value;
Determination means for determining whether or not the number of image candidates counted by the counting means is one;
Control means for ending the instruction by the first instruction means when a positive determination is obtained by the determination means, and continuing the instruction by the first instruction means when a negative determination is obtained. It is characterized by.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
The configuration of the projector system relating to the hardware according to the first embodiment of the present invention can be substantially the same as that of the prior art of FIG. 1 and has been described in the background art of the present specification, so detailed description thereof will be omitted here. .

  In order to explain the present invention, the internal configuration of the personal computer 10 of FIG. 1 will be briefly described. Not only the personal computer 10 but also an information processing device using a CPU or an electronic circuit combined with a logical operation circuit can be used as the personal computer 10.

  A CPU 1000 executes a program mounted on the hard disk 1030 of the personal computer 10.

  Reference numeral 1010 denotes a system memory, which includes a ROM and a RAM. The system memory 1010 stores a storage area for loading a program executed by the CPU 1000, a storage area for storing an image to be displayed on the display 1020, and various information used when the CPU 1000 executes information processing. A storage area is provided. In addition, a storage area for storing an image for projector screen display (projection) is also provided.

  A display 1020 displays the same image as the projection image projected by the projector 20.

  Reference numeral 1030 denotes a hard disk for storing a program described later (FIG. 3). A program executed by the CPU 1000 is loaded from the hard disk 1030 to the system memory 1010 and then executed by the CPU 1000.

  Reference numeral 1040 denotes an input / output interface that inputs a photographed image from the light receiver 40 and outputs a shutter speed instruction signal to the light receiver 10. In the present embodiment, a commercially available CCD whose shutter speed can be variably set by an instruction signal from the personal computer 10 is used as the CCD used in the light receiver 40. Further, the projection image is transmitted from the input / output interface 1040 to the projector 20. Conventional input / output devices such as a mouse and a keyboard can be connected to the input / output interface 1040.

  FIG. 3 shows the configuration of software installed in the personal computer 10 in the first embodiment of the present invention. In FIG. 2, a projector program 2000 is a program for transmitting a projection image created by a projection image generation program (described later) 2010 to the projector 20. The function for this is the same as the conventional one. In the first embodiment of the present invention, in addition to the function of the conventional projector program, in order to optimize the degree of blur processing applied in image processing for CCD shutter speed and laser pointer detection of the light receiver 40. (FIG. 4) is provided in the projector program.

  2010 is a projection image generation program, which is a well-known program for creating an image to be projected. For example, word processor software, form processing software, drawing software, presentation content creation software, and the like are well known. Since the projection image created by these software is stored in a storage area in the system memory 1010 used for displaying on the display of the personal computer 10, the projection image is stored in the projector program via this storage area. (The projector program 2000 reads out from the storage area).

  2020 is, for example, an operating system 2020 such as Windows (registered trademark) of Microsoft Corporation, and the above-described program runs on the operating system.

  FIG. 4 is a program for determining the CCD shutter speed and the degree of blurring (blurring range) optimal for detecting the laser pointer. When the projector program 2000 is activated, initial processing is performed. Run as. At this time, a projection image prepared in advance is displayed on the projector screen 60 via the projector 20, and the presenter designates an arbitrary position on the projector screen 60 with the laser pen 30. And

  In FIG. 4, the CPU 1000 of the personal computer 10 (hereinafter simply referred to as “CPU”) sets an initial value for the shutter speed in S10, and sets an initial value for the degree of blurring in S20. In this example, in order to perform the blurring process on the photographed image of the light receiver 40, the value of the image data of the target pixel is corrected by weighted average calculation (note: known) of the image data with the target pixel and neighboring pixels. The first novel feature of the present embodiment is to increase the range of neighboring pixels used in the weighted average calculation until a suitable degree of blurring, that is, until a laser pointer image to be detected is found.

  The CPU stores the captured image from the light receiver 40 in the system memory 1010, and then performs the blurring process described above on the stored captured image. Note that since there is no blur in the initial setting, the image data of the photographed image becomes the image data after blur processing as it is (S30).

The CPU detects the image of the laser pointer using the image data after the blurring process. Specifically, the following processing is executed in S40.
(1) The average value of the brightness of all the image data after being subjected to the blurring process is calculated (the CPU at this time functions as the first calculation means of the present invention).
(2) The difference value between the luminance of the image data of each pixel and the average value of the calculated luminance is calculated (the CPU at this time functions as the second calculation means of the present invention).
(3) The obtained difference value is compared with a predetermined threshold value, and the number of image candidates of the laser beam having a difference value larger than the threshold value is counted (the CPU at this time serves as the counting means of the present invention) function).

  In this embodiment, a laser pointer image forms a closed section, and a partial image having a predetermined number or more of pixels in the closed section is set as a laser pointer image candidate. Since the processing situation of detecting a closed section and counting the total number of images in the closed section is well known, it will not be described in detail here. Those skilled in the art will readily understand.

  Since the laser light is very thin, the image of the laser pointer evaluated by the light receiver 40 is an image of a small point. In this embodiment, the image of the dots is enlarged by performing blurring processing on the photographing data of the light receiver 40. This increases the accuracy of detecting the image of the laser pointer even if the projected image is mixed in the captured image. In addition, for projection images other than the image of the laser pointer, the image data is smoothed by the blurring process, so that the value of pixel data with high luminance is small. Further, since the entire image data average value and the difference value of each pixel are compared with a threshold value, the probability that a part of the projection image that is not the laser pointer is a candidate for the laser pointer image is reduced. Furthermore, by changing the shutter speed, which will be described later, images other than the projection image having a component close to the laser light are not captured by the light receiver 40. These points are the second new feature of the present embodiment.

  In this way, when the number of laser pointer candidate images is counted in S40, it is determined in S50 whether or not the counted number is one (whether it is one). The CPU at this time functions as the determination means of the present invention.

  When the laser beam is very thin and cannot be detected by the image processing of S40, the count value is 0 (zero). Conversely, when a partial image in the background image is erroneously determined as a laser pointer image candidate. The count value is 2 or more.

  In such a case, since the determination process in S50 is NO, the CPU proceeds to S60, where it is confirmed that the current blur level is not the final value, and in S65, the current blur level is increased. Increase the setting value so that Since there is currently no default blurring, in S65, eight pixels surrounding the target pixel are set as neighboring pixels used for the blurring process. Since the procedure returns to S30, the blur processing is executed by the CPU with the degree of blur set for the photographed image. In the case of a slow laser beam, the procedure of S30 to S50 → S60 → S65 → S30 is repeatedly executed, so that the image of the true laser pointer is enlarged by the blurring process. Is determined (YES determination), and the degree of blurring at this time is fixedly used in the detection of the laser pointer thereafter. In S65, since the degree of blurring is instructed renewably, the CPU for executing the processes in S20 and S65 functions as the first instruction means of the present invention.

  If the image of the laser pointer cannot be detected even after increasing the blur level (expanding the range), the blur level reaches the final value. In this case, in order to stop the loop processing, it is determined in S60 that the degree of blurring has reached the final value. If a YES determination is obtained, the CPU determines that the shutter speed has not reached its final value in S70, and updates the set value of the shutter speed in S80. Increase the speed of the rice field a little. As a result, the entire captured image of the light receiver 40 becomes darker than before.

  The procedure returns from S80 to S20, and the degree of blurring is returned to the initial value. Thereafter, the procedures from S30 to S50 → S60 → S65 → S30 are repeated again, and the degree of blur is sequentially increased to detect the image of the laser pointer.

  In this way, if the degree of blur is increased sequentially, and if the image of the laser pointer cannot be detected even if the shutter speed is increased, the indicated blur level and shutter speed will reach the final value. In the procedure, the determination process in S60 and the determination process in S70 are both YES, and the procedure proceeds to S200. In S200, the CPU displays an error message indicating that the laser pointer cannot be detected on the display 1020, and fixes the shutter speed and the degree of blurring prepared in advance, and ends this procedure.

  In the above processing procedure, the CPU when executing the processing of S10 and S80 corresponds to the second instruction means of the present invention.

  Note that if the captured image is bright and a part of the projected image is mistakenly detected as a laser pointer image, increasing the shutter speed will darken the projected image and avoid false detection. .

(Other embodiments)
(1) In the above-described embodiment, the degree of blurring is changed first and the shutter speed is changed later. However, the order of change may be reversed.
(2) As the blurring process, a Gaussian blurring process and other blurring processes are widely known. Therefore, a suitable blurring process may be selected according to the characteristics of the light receiver 40.
(3) In the above-described embodiment, the processing procedure of FIG. 4 is performed at the start of use of the projector, but may be performed every time the projection images are sequentially switched.

It is a block diagram which shows the hardware constitutions of a prior art example. It is a block diagram which shows the schematic structure of the hardware of the personal computer 10 of the 1st Embodiment of this invention. It is a block diagram which shows the structure of the software of the 1st Embodiment of this invention. It is a flowchart which shows the process sequence of the optimization process of the 1st Embodiment of this invention.

Explanation of symbols

1000 CPU
1010 System memory 1020 Display 1030 Hard disk 1040 Input / output interface

Claims (2)

The image is projected on the projector screen, and the reflected light of the laser beam irradiated as a laser pointer on the projector screen by the laser pen is received by the light receiver, and the laser pointer on the light receiving screen detected by the light receiver is received. In a projector system for detecting a designated position by the laser pen on the projector screen by converting a position to a position of the laser pointer on the projector screen.
First instruction means for repeatedly instructing while changing the degree of blurring from an initial value to a final value;
Image processing means for subjecting image data of all pixels on the light receiving screen of the light receiver to a blurring process to the extent instructed by the first instruction means;
First calculation means for calculating an average value of luminance of all the image data after the blur processing is performed;
Second calculation means for calculating a difference value between the luminance of the image data of each pixel and the average value of the luminance calculated by the first calculation means;
Counting means for comparing the difference value obtained by the second calculation means with a predetermined threshold value and counting the number of image candidates of the laser beam having a difference value larger than the threshold value;
Determination means for determining whether or not the number of image candidates counted by the counting means is one;
Control means for ending the instruction by the first instruction means when a positive determination is obtained by the determination means, and continuing the instruction by the first instruction means when a negative determination is obtained. Projector system characterized by   2. The projector system according to claim 1, wherein the light receiver can variably set a shutter speed in accordance with an instruction from the outside, and repeatedly instructs the shutter speed while changing the shutter speed from an initial value to a predetermined value. While the instruction by the first instruction means and the instruction by the first instruction means are performed, the second instruction means fixes the shutter speed to be instructed to the light receiver, and the instruction of the first instruction means A projector system characterized by changing a shutter speed to be instructed when the degree of blurring reaches the specific value, and then the first instruction means instructs the degree of blurring from an initial value.

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