KR20190074585A - Method, apparatus and program stored in storage medium for focusing for video projector - Google Patents

Abstract

A method for focusing for a video projector comprises: a photographed image generating step of photographing a projection image projected on a screen from a video projector to generate a photographed image; a depth difference calculating step of calculating a depth difference corresponding to a blur degree of the photographed image with respect to a sharp reference image; and an autofocus (AF) control signal generating step of generating a signal for AF control of the video projector from the depth difference.

Description

METHOD, APPARATUS AND PROGRAM STORED IN STORAGE MEDIUM FOR FOCUSING FOR VIDEO PROJECTOR,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focusing method for a video projector, an apparatus, and a program stored in a storage medium, and more particularly to a method and apparatus for focusing a video projector according to the degree of blur (blur) And a program stored in a storage medium, the focusing method for a video projector for outputting an AF control signal for focusing correction to a module.

Generally, in a video projector that projects an image on a screen, the distance between the screen and the video projector may vary, and it may be necessary to focus the projected image according to this distance.

Conventionally, as disclosed in the patent document, an autofocusing circuit of a liquid crystal projector that automatically focuses according to the distance between a projector and a screen and the size of a screen in a liquid crystal projector, Distance sensing means; A microcomputer for outputting a focus control signal according to the distance sensed by the distance sensing means; A motor driving unit for driving the focusing motor according to a focus control signal output from the microcomputer; And a lens moving unit for moving the focus adjusting lens forward or backward according to the operation of the focusing motor to adjust the focus of the image projected on the screen.

Registration Practical Utility Model No. 129657

However, in the above-described patent document, although focusing is performed according to the distance, there are cases where the focusing is also changed when the image size on the screen is changed. In such a case, focusing can not be achieved only by the distance, and there is a problem that it is troublesome to focus again according to the size change.

In addition, in the above-mentioned patent document, the microcomputer outputs the focus control signal according to the distance between the projector and the screen, but actually there is no disclosure about the concrete means for measuring the distance. In addition, known distance measuring methods can not always be used to calculate accurate distance values in a video projector environment.

For example, the ultrasonic method is a method of measuring the time difference of a wave coming back from the ultrasonic wave to the screen and determining the distance to the screen. This is how the focus is automatically adjusted to the calculated distance. However, in this method, an ultrasonic actuator and a sensor for capturing a reflected wave are required. In addition, ultrasonic distance meters are significantly less accurate in noise environments such as factories and motorways.

In addition, the TOF method is a method of measuring the time difference of the infrared ray by returning the infrared ray to the screen and determining the distance. This is similar to the ultrasonic method. However, this method also requires an IR emitter and IR camera sensor. In places where there are many infra-red influences such as morning and evening, or in the vicinity of a volcano, etc., the accuracy is significantly lowered.

Likewise, the laser rangefinder is significantly less accurate in intense light environments, such as sunlight.

The method of calculating the distance by receiving the reflected wave after the emission of the wave such as the light wave or the sound wave is reduced in accuracy due to the influence of the disturbance due to the noise from the surrounding environment. Therefore, there is a problem that a distance measurement by a reflected wave and a distance measurement mechanism of a different method are required.

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the problems of the related art as described above and it is an object of the present invention to provide an image processing apparatus and a method for automatically changing a size of an image on a screen, And a program stored in a storage medium.

Then, an image projected on the screen is input from the video projector, and a signal for AF control for focusing correction is generated from a blur degree represented by depth information of the image, not the distance to the screen, To a focusing module for a video projector by which a video projector can focus, thereby providing a program stored in a storage medium.

By using the depth image (depth map) calculation function which is less influenced by the surrounding environment and is particularly resistant to noise and low-light conditions, the degree of blur converted from the depth information of the depth image is minimized, And a program stored in a storage medium.

According to an aspect of the present invention, there is provided a focusing method for a video projector, comprising: a captured image generating step of capturing a projection image projected on a screen from a video projector to generate a captured image ; A depth difference calculating step of calculating a depth difference corresponding to a degree of blur of the sensed image with respect to a sharp reference image; And an AF control signal generating step of generating an AF (autofocus) control signal of the video projector from the depth difference.

Here, the captured image is composed of an RGB image of a visible light ray, an IR image of infrared rays, and a depth image calculated from the RGB image and the IR image, which are captured at the same angle by one imaging device at the same angle desirable.

The depth difference is calculated by dividing the PSF of the depth image output according to the degree of blur of the RGB image with respect to the reference image It is preferable to calculate it based on the difference of the index values .

Here, it is the PSF index value is preferably being expressed in number of pixels and, by the number of pixels of a blurred portion of the RGB image is the blur degree calculation.

The depth difference calculating step may include: an average depth calculating step of calculating an average depth from the captured image; And this is preferred yirueojim including the step in terms of the blur degree of blur degree corresponding to an average depth from the conversion.

Preferably, the AF control signal generating step calculates the AF control signal value so as to determine whether the degree of blur is the minimum, terminate the processing when the minimum level is the minimum level, and reduce the level of blur if the minimum level is not the minimum level.

On the other hand, a focusing method for a video projector according to another embodiment includes a captured image generating step of capturing a projection image projected on a screen from a video projector to generate a captured image ; A depth calculating step of calculating a depth up to a subject corresponding to a degree of blur of the sensed image; And an AF control signal calculation step of generating an AF control signal of the video projector from the depth.

Here, it is preferable that the AF control signal corresponding to the depth is calculated by using an experiential experiential value which is a ratio between the depth and a displacement distance for driving the actual motor, and an AF control signal.

And the presentation image including the captured image or the captured image is recorded .

According to another aspect of the present invention, there is provided a focusing apparatus for a video projector, comprising: a captured image generating unit for capturing a projection image projected on a screen from a video projector to generate a captured image ; Calculating a depth difference corresponding to a degree of blur of the sensed image with respect to a sharp reference image, A calculating unit ; And an AF control signal for generating an AF (autofocus) control signal of the video projector from the depth difference And a biological part .

According to another aspect of the present invention, there is provided a program stored in a storage medium readable by an information processing device, the program causing the information processing device to perform the steps of the above- The program being stored in a storage medium readable by the computer.

According to the present invention, it is possible to automatically focus the image on the screen by the video projector regardless of the size of the image even if the user freely changes the size of the image projected on the screen. And to provide a program stored in a storage medium.

Then, an image projected on the screen is input from the video projector, and a signal for AF control for focusing correction is generated from a blur degree represented by depth information of the image, not the distance to the screen, To a focusing module for a video projector by which a video projector can focus, thereby providing a program stored in a storage medium.

By using the depth image (depth map) calculation function which is less influenced by the surrounding environment and is particularly resistant to noise and low-light conditions, the degree of blur converted from the depth information of the depth image is minimized, And a program stored in a storage medium.

FIG. 1 is a schematic block flow chart for implementing an autofocus and video recording function of a video projector using an information extraction device, for example, DR 1152, according to an embodiment of the present invention.
2 is an exemplary photograph of an RGB image, IR image, and depth image captured by a general video projector and its screen, and the information extraction device of the present invention, e.g., DR1152.
3 is an exemplary photograph of a Blur RGB image and its corresponding depth image, and a Sharp RGB image and its corresponding depth image.
4 is an exemplary graph showing the concept of calculating an AF control signal using the blur degree difference.
5 is a diagram showing a formula and a concept for calculating an actual distance in a blur magnitude (size).
6 is a block flow chart of an autofocus and video recording function according to an embodiment of the present invention.
7 is a plan schematic layout of an information extracting apparatus, a video projector, a screen, a user, and a projection image according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to specific embodiments thereof with reference to the accompanying drawings. However, portions having the same function due to the same configuration are denoted by the same reference numerals even if they are different from each other, and detailed description thereof may be omitted. And one step or module may be implemented as two or more steps or modules, and conversely, two or more steps or modules may be merged into one step or module. The apparatus for performing the method may be implemented by hardware and a fixedly formed circuit, or may be implemented by a circuit that can be variably changed by a program installed in the hardware. As an image to be recorded, an RGB image is described in the following description, but the same applies to an IR image.

<Basic Configuration>

A focusing method for a video projector according to an embodiment of the present invention includes: an imaging image generating step (10 to 40) ; A depth difference calculation step 51 ; And an AF control signal generating step (52, 53) .

Fig. 2 shows the overall system configuration. There is a general video projector 60 and screen s, and an information extraction device 10, for example a DR1152 camera system, is installed independently of it. The RGB image 20, the IR image 30, and the depth image 40, which are the output of the information extracting apparatus 10, Show on monitor.

The captured image generating step (10 to 40) is a step of capturing a projected image (i ₀ ) projected on a screen (s) from a video projector (VP) 60 to generate a captured image (i).

Figure 3 shows the projected image on the screen and its corresponding depth image (depth map). 3 is a blurred image on the screen s of the projector 60 on the upper side and a depth image 40 derived from the information extracting apparatus 10, for example, the DR 1152 on the lower side. 3 is an image (sharp image) focused on the screen s of the projector 60. The lower side of the image is the information extracting apparatus 10 corresponding thereto, the depth of the DR1152 (40).

In the present invention, the degree of blur of a blurred image on the left side is sensed to calculate a distance difference, and then a correction control signal? Z is generated to send it to a module that performs an AF function of the projector.

Since the projected image i ₀ is expressed by light on the screen s on the plane, the perspective is recognized on the projected image io even if the sky, mountain, automobile, Even if objects are represented, the actual physical depth is the surface (s) of the screen. Therefore, when the depth is measured by the reflected wave with ultrasonic waves, infrared rays, laser beams, etc. as in the conventional art, all the depths of the surface of the physical screen s are output. That is, the distance between the screen s and the video projector 60 can be known only by the method of these ultrasonic waves, the infrared ray, and the laser beam.

Incidentally, the operation of the AF module according to the correlation between the distance and the focus differs from one video projector 60 to another. This is because the specifications of the employed AF module, specifically the motor, the lens, the case, and the like are different. Therefore, even if the distance between the screen s and the video projector 60 is known, if an error occurs in the operation of the AF module, the correlation is not applied and the focusing may not be performed.

In the present invention, there is a large difference from the conventional techniques in that the image is picked up by the image (i) and the focusing is performed therefrom, so that focusing is performed by the same image that the human recognizes with the eye.

The step of calculating the depth difference is a step of calculating a depth difference corresponding to a blur degree (d) of the captured image (i) with respect to a sharp reference image (i ').

The graph of Fig. 4 shows the concept of calculating the AF control signal? Z using the blur difference. The solid line represents the average value, and the dotted line represents the standard deviation.

Here, the information extracting apparatus 10 of the present invention, for example, DR1152, has a depth value curve characteristic as shown in FIG. PSF index values (values between 1 and 121) are output differently depending on the degree of blur of the image. The higher the blur, the greater the PSF value.

In FIG. 4, a depth image (depth map, left side) when the screen is blurred (blurred) and a depth image (right side) when the image is focused (sharp) is shown in the depth curve. The difference value of the PSF index values in the two cases represents the depth difference (distance difference).

The captured image (i) is a planar image, but may have a sense of depth. This depth sense can be extracted from the degree of blur (d) of the captured image (i). That is, the depth information of each pixel unit can be extracted according to the boundary line and the degree of blur of the captured objects in the captured image (i).

In the present invention, the depth difference is calculated from the depth information according to the degree of blur (d) of the captured image (i) and the depth information of the reference sharp image (i '). The sharp reference image (i ') is an image in a focused state, which may be a pre-stored image or a virtual image estimated by removing blur from the captured image (i).

The AF control signal generating step is a step of generating an AF (autofocus) control signal? Z of the video projector 60 from the depth difference.

In the graph of Fig. 4, the AF control signal? Z is generated from the depth difference.

The depth difference means a distance to be moved in the depth direction in order to sharpen the reference image (i ') by removing blur of the current captured image (i) to perform focusing. Therefore, the AF module of the video projector needs to be moved in an amount corresponding to the depth difference to perform focusing.

The AF control signal? Z may include a value calculated by reflecting the experience value set for each video projector 60 in order to reflect the depth difference.

<Effect>

According to the configuration of the present invention, the screen (s) surface and the video projector 60, the image pickup image (i) the distance, not the (a), Rimed projected image on the screen (s) (i ₀₎ between the blur And performs focusing using the depth difference calculated from the depth d.

Therefore, in the prior art, if an error occurs due to focusing according to the distance a, the focusing can not be corrected automatically even if it is repeated in the same manner, but according to the present invention, Since focusing is performed by the depth difference based on the sensed image (i), it is possible to achieve pivotability that can be practically used by, for example, only one focusing without focusing according to the distance. For example, And then superimposing it in such a manner as to perform the second-order focusing by the depth difference again, almost perfect focusing can be achieved.

Further, the present invention uses a method of calculating the distance by sensing the degree of blur of the sensed image (i) of the projected image on the screen coming from the video projector itself, so that it is possible to use additional emitters such as ultrasonic actuators or IR emitters And does not need its receiver. It is not affected by external noise.

In addition, since the IR image is acquired at the same time, a very excellent focusing effect is obtained even in a low-illuminance environment.

&Lt; Imaging and information extracting device >

As a device for generating the sensed image (i), a general visible light camera, that is, an RGB camera, is exemplified, but an infrared camera, for example, an IR camera may be used. However, there is a definite limit to producing depth images with only one kind of image.

Thus, the captured image i preferably comprises an RGB image 20 , an IR image 30 and a depth image 40 ( depth map ) .

In this case, preferably, the RGB image 20 and the IR image 30 are images obtained by simultaneously capturing the projection image i0 by one imaging device 11 at the same angle, The RGB image 20 is an image made up of visible light, and the IR image 30 is an infrared It is an image made.

The image pickup device 11 may include a four-color sensor of a dual aperture (DA) single lens type. The depth image (40, depth map ) is calculated from the RGB image (20) and the IR image (30) and includes depth information. The depth image 40 calculating device 12 extracts depth information using the specific focus of the RGB image 20 and the all-in focus characteristic of the IR image 30 to generate a depth image can do. The image pickup device 11 and the depth image calculation device 12 can constitute one information extraction device 10.

A technology to extract the depth with a double-aperture single-lens camera was implemented by the semiconductor system of DR1152 by W. V. Co., Ltd. The DR1152 is a system that simultaneously provides RGB image and IR image as well as 3D depth image (depth map) information based on a single lens. The present invention can realize a video autofocus function by utilizing the DR1152 system. In addition, video recording functions can be added using the RGB signals of the DR1152 system.

That is, the present invention is a technique for implementing autofocus of a video projector based on three-dimensional depth information of a double-aperture single lens system and an apparatus for extracting infrared information.

<PSF index>

In this case, the depth difference is determined by the PSF of the depth image 40, which is output according to the degree of blur (d) of the RGB image 20 for the reference image i ' It is preferable to calculate it based on the difference of the index values .

In generating the depth image 40 from the RGB image 20 and the IR image 30 by the dual-aperture single-lens system four-color sensor, the degree of blur is changed in multiple stages for the all-in-focus IR image 30 There is a method of forming a PSF index, comparing it with the RGB image 20 in pixel units, and determining the depth according to the PSF index. The depth difference can be calculated according to the difference of the PSF index values.

And PSF is the index value is preferably a search is represented by a number of pixels, the blur blur degree (d) by the number of pixels of pieces of RGB image 20 is calculated. That is, since the PSF index value is clearly known according to the number of pixels, the depth difference can be clearly and easily calculated from this.

<Necessity of Average Depth>

As shown in Fig. 7, since the apparatus used in the present invention is the information extracting apparatus 10 and the video projector 60, at least one of them is in alignment with the center of the screen s There is no other way. In the case of Fig. 7, the video projector 60 is arranged in the center of the screen s, but the information extracting apparatus 10 shows a situation in which it is not aligned.

In this case, the picked-up image (i), which is the output of the information extracting apparatus 10, can be misjudged to output different depth values for the object whose actual depth is to be calculated. For example, in the case of FIG. 7, the depth of the projected image on the right end (re) side may be deeper than the projected image on the left end (le) side of the screen (s).

Conversely, although the information extracting apparatus 10 is arranged, even if the video projector 60 is not aligned, portions to be output at the same depth may be output at different depths.

7, since the depth line of the arcuate shape represents the same depth, but the screen s is a planar shape, the depth of the object expressed on the screen There is a possibility that there will be a difference in the central part and the upper and lower ends.

In order to prepare for such a situation, the depth difference calculating step according to another embodiment of the present invention includes: calculating an average depth ; It is preferred including yirueojim and blur extent in terms of phase. The average depth calculating step calculates an average depth from the captured image (i). The average depth can be calculated by averaging the left and right ends, or the top and bottom, or the center and the end. The blur degree conversion step is a step in which the corresponding blur degree (d) is converted from the average depth. Therefore, it is possible to eliminate a distortion phenomenon and to calculate a more accurate depth difference.

&Lt; Judgment of minimum blur and calculation of new control value >

The AF control signal generating step includes a step of determining whether the blur degree (d) is the minimum, terminating the process when the minimum is determined, and decreasing the blur degree (d) DELTA z) is preferably calculated.

For example, when the degree of blur of the first-time picked-up image (i) is the minimum, the control signal can be terminated without being calculated, so that rapid processing is possible.

For example, when the degree of blur of the second-time captured image (i) automatically executed after the first-time processing is minimized, since the focusing is performed only once, rapid processing is also possible.

For example, the above process may be repeated several times. By repeating the process of generating the captured image (i), determining the degree of blur, and calculating and applying the AF control signal value (? Z) for decreasing the degree of blur, control for converging the blur degree of the captured image (i) And a focusing technique based on the degree of blur of the captured image is included in the scope of the present invention. At this time, fine adjustment can be made by reducing the AF control signal value.

&Lt; Control signal calculation based on the depth calculated in the blur of the captured image >

According to another embodiment of the present invention, there is provided a focusing method for a video projector, comprising: generating an imaging image (10 to 40) ; A depth calculating step 51 ; And an AF control signal calculating step (FIG. 5) . This embodiment is to generate a control signal directly from the depth, not the depth difference.

The captured image generating step (10 to 40) is a step of capturing a projection image projected on a screen from a video projector to generate a captured image. Since this is the same as the previous embodiment, detailed description will be omitted.

The depth calculating step is a step of calculating a depth up to a subject corresponding to the degree of blur of the captured image.

5 shows a method of calculating the distance (depth) between the information extracting apparatus 10 and an object in the degree of blur (size), from which the correction AF control signal? Z is calculated.

As shown in Fig. 5, when the optical theory is applied to the double-iris type of the present invention, the degree of blur (blur size) of the subject can be converted to the actual depth (distance). In the following equations (1) and (2), a represents the distance to the actual object, and the degree of blur of the object formed on the image sensor is represented by d. That is, if d is known, a can be obtained.

Here, f represents the focal point of the lens itself, and a ₀ represents the focal length of the camera which is set so that the object is focused on the image sensor.

The composite F number (F #) represents the composite value of the IR iris and the RGB iris, and is expressed by the following equation (3).

을 이용하여, PSF인덱스를 픽셀 수로 표현이 가능하고, 이는 이미지 센서에 맺힌 블러 이미지의 픽셀 수를 알아내면, PSF인덱스 값을 결국 블러 정도(사이즈)로 표현이 가능함을 의미한다. 이를 이용하면, 수학식 1 혹은 2를 이용하여, 실제 거리 a값을 구할 수 있다.Here, the condition

The PSF index can be represented by the number of pixels. If the number of pixels of the blurred image formed on the image sensor is known, it means that the PSF index value can be expressed by the degree of blur (size). Using this, the actual distance a value can be obtained using Equation (1) or (2).

The AF control signal calculating step is a step of generating an AF control signal of the video projector from the depth. In the present invention, the a value is calculated using this process, and the experiential value in which the a value is associated with the control signal? Z is calculated and output.

That is, the AF control signal corresponding to the depth is calculated using the experiential experience , which is a ratio between the depth a and a displacement distance for driving the actual motor, and the AF control signal? Z .

According to this configuration, since the AF control signal is calculated and applied after once calculating the distance, the conventional technique may be applied. However, the calculation of distance

<Recording function for screen and presentation users>

As shown in Figs. 1 and 6, it is preferable that a moving picture including the sensed image (i) or the sensed image (i) is recorded . For this purpose, a recording unit 21 may be provided.

That is, the present invention can implement a separate device recording function for the projected video of the video projector based on the three-dimensional depth information of the double-iris single lens system and the apparatus for extracting infrared information. Although the RGB image 20 is preferably used as the captured image i used for the recording, the IR image 30 or the depth image 40 may be used. This makes it possible to simultaneously present the presenter and the presentation screen.

<Focusing device for video projector>

According to another aspect of the present invention, there is provided a focusing apparatus for a video projector, comprising: a captured image generating unit ; Depth difference A calculating unit ; And an AF control signal And a generating unit .

The captured image generating unit is a member that captures a projected image (i0) projected onto the screen (s) from the video projector (60) to generate a captured image (i).

The depth difference The calculating unit is a member for calculating a depth difference corresponding to a blur degree (d) of the sensed image (i) with respect to a sharp reference image (i ').

The AF control signal The generating unit is a member for generating an AF (autofocus) control signal? Z of the video projector 60 from the depth difference.

<Program stored on storage medium>

Meanwhile, a program stored in a storage medium readable by the information processing device according to an embodiment of the present invention may include a program for causing the information processing device to perform the steps of the above-described focusing method for a video projector, Lt; RTI ID = 0.0 &gt; a &lt; / RTI &gt; The information processing device includes not only a computer but all the devices in the current and near future that process information in digital or analog to perform predetermined processing.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, All modifications, changes, and alterations made by those skilled in the art are to be construed as being within the scope of the present invention. For example, in the above embodiment, a control signal is generated from the depth difference or a control signal is generated from the depth. However, the present invention is not limited to this, and the actual depth may be calculated using the depth difference, May be applied to generate a control signal.

The present invention can be applied to a focusing method for a video projector, an apparatus, and a program stored in a storage medium.

10: information extraction device
11: Dual Aperture Single Lens 4 Color Camera
12: Depth image calculating means
20: RGB image
21: Recording section
30: IR image
40: Depth image (depth map)
50: Focusing device
51: average depth calculating section
52: minimum blur determination unit
53: New AF control signal calculating section
60: Video projector
i ₀ : Projected image
i: Imaging image
s: Screen
re: right side
le: left end
h: Presentation users

Claims (11)

A focusing method for a video projector,
A captured image generating step of capturing a projection image projected on a screen from a video projector to generate a captured image ;
A depth difference calculating step of calculating a depth difference corresponding to a degree of blur of the sensed image with respect to a sharp reference image; And
An AF control signal generating step for generating an AF (autofocus) control signal of the video projector from the depth difference;
And adjusting the focusing position of the focusing lens. The method according to claim 1,
The captured image may include:
One is the projected image is captured by the same angle by the image pickup device, the RGB visible light image and an infrared image are obtained at the same time, IR and
A depth image calculated from the RGB image and the IR image
The method of claim 1, The method of claim 2,
The depth difference is calculated based on a difference in the PSF index value of the depth image output according to the degree of blur of the RGB image with respect to the reference image
And a focusing step for focusing the light beam on the projection optical system. The method of claim 3,
The PSF index value is expressed by the number of pixels ,
The degree of blur is calculated by the number of pixels of the blur portion of the RGB image
And a focusing step for focusing the light beam on the projection optical system. The method according to claim 1,
The step of calculating the depth-
An average depth calculating step of calculating an average depth from the captured image; And
Blur degree in terms of the blur degree steps from the corresponding terms of the average depth
And adjusting the focusing position of the focusing lens. The method according to claim 1,
The AF control signal generating step determines whether the degree of blur is the minimum, finishes the processing when the minimum level is determined, and calculates the AF control signal value to reduce the level of blur if the minimum level is not the minimum level
And a focusing step for focusing the light beam on the projection optical system. A focusing method for a video projector,
A captured image generating step of capturing a projection image projected on a screen from a video projector to generate a captured image ;
A depth calculating step of calculating a depth up to a subject corresponding to a degree of blur of the sensed image; And
An AF control signal calculation step of generating an AF control signal of the video projector from the depth
And adjusting the focusing position of the focusing lens. The method of claim 7,
The AF control signal corresponding to the depth is calculated using an experiment experience value which is a ratio between the depth and a displacement distance for driving the actual motor and AF control signals
And a focusing step for focusing the light beam on the projection optical system. The method of claim 1 or claim 7,
The presentation image including the captured image or the captured image is recorded
And a focusing step for focusing the light beam on the projection optical system. 1. A focusing device for a video projector,
A captured image generating unit for capturing a projection image projected on a screen from a video projector to generate a captured image ;
A depth difference calculating unit for calculating a depth difference corresponding to a degree of blur of the sensed image with respect to a sharp reference image; And
An AF control signal generating unit for generating an AF (autofocus) control signal of the video projector from the depth difference ,
And a controller for controlling the focusing of the video projector. A program stored in a storage medium readable by an information processing device,
A program for causing each of the steps of the method according to claim 1 to be performed on an information processing device is stored in a storage medium readable by the information processing device.

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