JP5887777B2 - Projector and projector control method - Google Patents

Description

  The present invention relates to a projector and a projector control method.

  Generally, a projector that projects an image on a projection surface includes a mechanism that automatically adjusts distortion and focus of a projection image formed on the projection surface. Such adjustment cannot be performed properly if the projector is moving. For this reason, conventionally, a movement determination sensor such as an angular velocity sensor is mounted, and this sensor is used to detect whether or not the projector is stationary with respect to the projection surface (see, for example, Patent Document 1). ).

JP 2010-109585 A

Recently, electronic devices are required to be downsized and the number of parts reduced, and projectors are no exception.
The present invention has been made in view of the above-described circumstances, and provides a projector that can determine the movement of the projector relative to the projection surface, can be reduced in size, and can reduce the number of components, and a projector control method. With the goal.

In order to achieve the above object, the present invention provides a projector that projects an image on a projection surface, the image capturing unit capturing a range including the image projected on the projection surface, and the image capturing performed by the image capturing unit. The image processing apparatus includes: a shake detection unit that detects a shake in the image; and a movement determination unit that determines a movement of the projector with respect to the projection plane based on a detection result of the shake detection unit.
According to the present invention, since the movement of the projector relative to the projection surface can be determined even in a configuration that does not have sensors for detecting movement, the component can be maintained while maintaining its function as compared with a projector having sensors for detecting movement. It is possible to reduce the number of points and reduce the size.

According to the present invention, in the projector described above, a light source, a modulation unit that modulates light emitted from the light source based on an input image, a projection unit that projects the light modulated by the modulation unit onto the projection surface, A trapezoid that detects trapezoidal distortion of a projected image projected on the projection surface based on a captured image captured by the imaging unit and corrects the trapezoidal distortion of the projected image by processing an input image of the modulating unit. And a distortion correction unit.
According to the present invention, since the movement of the projector can be determined using the imaging unit that captures the projection surface in order to correct the trapezoidal distortion, the number of parts can be reduced.

In the projector according to the aspect of the invention described above, the projector includes a photographing control unit that controls a shutter speed of the imaging unit, and the photographing control unit photographs the photographed image for detecting a blur by the blur detection unit. The shutter speed of the imaging unit is set to a different speed when the captured image for detecting the trapezoidal distortion is captured by the trapezoidal distortion correcting unit.
According to the present invention, it is possible to obtain a photographed image suitable for trapezoidal distortion correction and a photographed image suitable for blur detection using a common imaging means, and therefore, different processing between trapezoidal distortion correction and blur detection. Can be performed with high accuracy.

In the projector according to the aspect of the invention, the shooting control unit may detect a trapezoidal distortion by using the trapezoidal distortion correcting unit when a shutter speed when the captured image for detecting the blur is detected by the blur detecting unit is captured. Therefore, the shutter speed is set to be longer than the shutter speed when the captured image is captured.
According to the present invention, an optimal shutter speed is set for each of shooting for detecting blur and shooting for detecting trapezoidal distortion, and a common imaging unit is used for the purpose. Therefore, it is possible to perform different processes of trapezoidal distortion correction and blur detection with high accuracy.

In the projector, when the movement determination unit determines that the movement of the projector relative to the projection surface is small, the trapezoidal distortion correction unit performs correction, and the correction by the trapezoidal distortion correction unit is performed. After the completion of the operation, it is provided with motion control means for starting shake detection by the shake detection means and determination by the movement determination means.
According to the present invention, the trapezoidal distortion correction is performed after the movement of the projector becomes small, thereby correcting the trapezoidal distortion under a preferable condition, and the trapezoidal distortion correcting operation in which an effect cannot be expected while the projector is moving. Can be achieved and efficient control can be realized. In addition, since the projector motion determination is resumed after the keystone distortion correction is executed, if the projector moves again, it can be easily determined whether the keystone distortion correction is necessary, and the keystone distortion correction is executed as necessary. Thus, the visibility of the projected image can be maintained.

In the projector according to the aspect of the invention, the shake detection unit may extract a plurality of areas from the captured image captured by the imaging unit, detect a shake for each area, and the movement determination unit may The movement of the projector with respect to the projection plane is determined by comparing the blurring of each area detected by the detection means.
According to the present invention, it is possible to prevent misjudgment due to camera shake that is not caused by the movement of the projector, and to perform efficient and highly accurate movement judgment.

In order to achieve the above object, the present invention provides a method for controlling a projector that projects an image on a projection surface, and detects blurring in a captured image obtained by capturing a range including the image projected on the projection surface. The movement of the projector relative to the projection plane is determined based on the detection result of the shake.
According to the present invention, it is possible to determine whether or not the projector is moving with respect to the projection surface even in a configuration that does not have sensors for detecting the movement of the projector. Is possible.

  ADVANTAGE OF THE INVENTION According to this invention, the motion of the projector with respect to a projection surface can be determined, and while reducing the number of parts, the projector which can be reduced in size can be implement | achieved.

It is an external view which shows an example of the use condition of the projector which concerns on embodiment. It is a block diagram which shows the functional structure of a projector. It is explanatory drawing which shows the mode of a process of a picked-up image, (A) shows the example of a picked-up image, (B) shows a mode that a picked-up image is divided into a some area | region, and is processed. It is a flowchart which shows operation | movement of a projector. It is a flowchart which shows the movement determination process which a projector performs. It is a flowchart which shows the trapezoid distortion correction which a projector performs.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an external view showing an example of a usage state of a projector 100 according to an embodiment to which the invention is applied.
In the example shown in FIG. 1, the projector 100 is installed in front of the screen SC (projection surface), projects projection light toward the screen SC, and a projection image 210 is formed on the screen SC. The screen SC illustrated in FIG. 1 is a screen in which a rectangular projection region is provided on the surface of a base fabric made of a synthetic resin film or woven fabric. The outside of the projection area is a black mask that hardly reflects the projection light. The projector 100 is installed so as to form a projection image 210 in the projection area of the screen SC, and a zoom magnification and the like to be described later are adjusted. The projector 100 is connected to an image supply device (not shown) via the cable 200 via the cable 200, and projects an input image input from the image supply device.

FIG. 2 is a block diagram illustrating an overall configuration of the projector 100 according to the embodiment.
The projector 100 includes a USB interface, a wired or wireless LAN interface, a VGA terminal to which an analog video signal is input, a DVI (Digital Visual Interface), NTSC, to which a digital video signal is input, as an interface to which the image supply device is connected. An S video terminal to which composite video signals such as PAL and SECAM are input, an RCA terminal to which composite video signals are input, a D terminal to which component video signals are input, an HDMI connector compliant with the HDMI (registered trademark) standard, etc. And an interface circuit (not shown) for inputting and outputting signals via these terminals and connectors, and the cable 200 is a cable suitable for the above-described interface. The projector 100 and the image supply device may be connected by wired communication or may be connected by wireless communication. Examples of the image supply device include a video playback device, a DVD playback device, a TV tuner device, a CATV set top box, an image output device such as a video game device, and a PC (Personal Computer). The projector 100 can project a video (moving image) on the screen SC or can continue to project a still image on the screen SC. Further, the projector 100 may incorporate a storage device and project an image of a video source (not shown) stored in the storage device.

  The projector 100 is roughly divided into an optical system that forms an optical image and an image processing system that electrically processes a video signal. The optical system functioning as a projection unit includes an illumination optical system 140 (light source), a light modulation device 130 (modulation means), and a projection optical system 150 (projection means). The illumination optical system 140 includes a light source including a xenon lamp, an ultra high pressure mercury lamp, an LED (Light Emitting Diode), and the like. The illumination optical system 140 may include a reflector and an auxiliary reflector that guide light emitted from the light source to the light modulation device 130, and includes a lens group (not shown), a polarizing plate, Or you may provide the light control element etc. which reduce the light quantity of the light which the light source emitted on the path | route which reaches the light modulation apparatus 130. FIG.

The light modulation device 130 is configured to include, for example, a transmissive liquid crystal panel, and forms an image on the liquid crystal panel in response to a signal from an image processing system described later. In this case, the light modulation device 130 includes three liquid crystal panels corresponding to the three primary colors of RGB in order to perform color projection, and the light from the illumination optical system 140 is separated into three color lights of RGB. Enters each corresponding liquid crystal panel. The color light modulated by passing through each liquid crystal panel is combined by a combining optical system such as a cross dichroic prism and emitted to the projection optical system 150.
The light modulation device 130 is not limited to a configuration using three transmissive liquid crystal panels, and for example, three reflective liquid crystal panels can be used, and one liquid crystal panel and a color wheel can be used. A combination system, a system using three digital mirror devices (DMD), a system combining one digital mirror device and a color wheel, or the like may be used. When only one liquid crystal panel or DMD is used as the light modulation device 130, a member corresponding to a composite optical system such as a cross dichroic prism is unnecessary. In addition to the liquid crystal panel and DMD, any configuration that can modulate the light emitted from the light source can be used without any problem.

  The projection optical system 150 includes a zoom lens 152 that performs enlargement / reduction of a projected image and a focus adjustment, a zoom adjustment motor 156 that adjusts the degree of zoom, and a focus adjustment motor 157 that performs focus adjustment. The projection optical system 150 receives the light modulated by the light modulation device 130 and forms a projection image on the screen SC using the zoom lens 152. The zoom lens 152 is adjusted by a zoom adjustment motor 156 and a focus adjustment motor 157 to adjust the lens position and the like, and zoom adjustment for enlarging / reducing the projected image on the screen SC, and projecting the projected image on the screen SC. Adjust the focus for proper image formation.

  The image processing system is configured around a CPU 120 and an image processor 134 that control the entire projector 100 in an integrated manner, and includes an A / D converter 110, a light modulator driving unit 132, a lens driving unit 155, a RAM 160, and distortion adjustment. A ROM 170 including an image storage unit 171, an imaging unit 180 including a CCD camera 181, a captured image memory 182, a remote controller control unit 190, a remote controller 191, an operation unit 195, and the like. These elements constituting the image processing system are connected to each other via a bus 102.

  The A / D conversion unit 110 is a device that performs A / D conversion on an analog input signal input from the above-described external image supply apparatus via the cable 200, and outputs the converted digital signal to the video processor 134. . The video processor 134 performs processing for adjusting the display state of the image such as luminance, contrast, color density, hue, and projected image shape on the digital signal input from the A / D conversion unit 110. The processed video signal is output to the light modulator driving unit 132. The light modulator driving unit 132 drives the liquid crystal panel of the light modulator 130 based on the video signal input from the video processor 134 and draws an image on the liquid crystal panel. By irradiating the liquid crystal panel with light emitted from the illumination optical system 140, the irradiation light is modulated and projected onto the screen SC via the projection optical system 150. As a result, a video corresponding to the video signal input to the A / D conversion unit 110 is formed on the screen SC as a projection image 210 (FIG. 1).

  Image processing performed by the video processor 134 includes trapezoidal distortion correction in addition to the above-described correction of brightness, contrast, hue, and the like. In FIG. 2, a circuit that performs trapezoidal distortion correction is shown as the trapezoidal distortion correction unit 136. The trapezoidal distortion correction unit 136 (trapezoidal distortion correction unit) performs trapezoidal distortion correction on the digital signal based on the projection distance and the projection projection angle values calculated by the CPU 120. The video processor 134 controls display of a specific distortion detection image in the trapezoidal distortion correction. The video processor 134 can be configured using a general-purpose processor sold as a DSP (digital signal processor) for trapezoidal distortion correction, or can be configured as a dedicated ASIC.

The CPU 120 performs image processing in the projector 100 together with the video processor 134. The CPU 120 includes a projection control unit 121, an imaging control unit 122, an image blur detection unit 123, a movement determination unit 124, a three-dimensional survey unit 125, and a projection angle calculation unit 126. Each of these units is realized by the CPU 120 executing a specific program stored in the ROM 170 in advance.
The projection control unit 121 (operation control unit) performs the operation of projecting an image, the imaging control unit 122, the image blur detection unit 123, and the movement determination when the projector 100 is turned on and starts projecting an image. Control of execution of movement determination processing described later by the unit 124 and execution of trapezoidal distortion correction processing by the imaging control unit 122, the three-dimensional surveying unit 125, the projection angle calculation unit 126, and the trapezoidal distortion correction unit 136 are controlled.

  The imaging control unit 122 (imaging control means) controls the imaging operation by the imaging unit 180. The projector 100 uses an image captured by the imaging unit 180 for both a movement determination process and a trapezoidal distortion correction process described later. The movement determination process is a process for determining the movement of the main body of the projector 100 by detecting a blur in the photographed image. Therefore, the longer the shutter opening time during photographing, the blur of the photographed image caused by the movement of the projector 100. Because it is easy to appear, shake can be detected more sensitively. On the other hand, in the trapezoidal distortion correction, it is only necessary to be able to detect the shape of the projected image 210 formed on the screen SC. Therefore, a sharp captured image is preferable, and it is better to shorten the shutter opening time. However, it is desirable that the shutter opening time is a time for obtaining a sufficient exposure amount so that a background image region 226 described later can be appropriately captured. Thus, since the preferable shutter opening time is different between the movement determination process and the trapezoidal distortion correction process, the imaging control unit 122 controls the shutter opening suitable for the content of the process using the captured image under the control of the projection control unit 121. The time is set, and the imaging unit 180 executes the shooting.

The image blur detection unit 123 (blur detection unit) detects a blur in a photographed image photographed under the control of the photographing control unit 122. The movement determination unit 124 (movement determination unit) determines whether the projector 100 is stationary or the projector 100 moves based on the magnitude of the blur detected by the image blur detection unit 123 and the temporal change in the magnitude of the blur. Judge whether it is. Here, the stillness and movement determined by the movement determination unit 124 refers to relative stillness and movement of the projector 100 with respect to the screen SC. Further, the stationary state of the projector 100 includes a case where it can be considered that the projector 100 is substantially stationary. Furthermore, the rest and movement of the projector 100 indicate that the housing or the body on which the projection unit including at least the projection optical system 150 is mounted is stationary or moved relative to the screen SC. There is no limitation on the shape and configuration of the main body and casing.
The three-dimensional surveying unit 125 and the projection angle calculation unit 126 are a projection angle (hereinafter referred to as a projection projection angle) that is an inclination of the screen SC with respect to the optical axis of the projection light projected from the projector 100, and a distance ( Hereinafter, it is referred to as a projection distance).

  When the CPU 120 calculates the projection projection angle and the projection distance by the functions of the respective processing units, the CPU 120 outputs a signal corresponding to the projection projection angle to the video processor 134 and outputs a signal corresponding to the projection distance to the lens driving unit 155. To do. When a signal corresponding to the projection projection angle is input from the CPU 120, the video processor 134 performs trapezoidal distortion correction based on this signal. When the projection projection angle, which is the angle formed by the optical axis of the optical system of the projector 100 and the screen SC, is specified, it is possible to determine how the image is distorted. When the parameter corresponding to the projection projection angle is set, the video processor 134 corrects the image input from the A / D conversion unit 110 so as to correct the distortion of the projection image, and the corrected video signal is obtained. And output to the light modulator driving unit 132. With the function of the trapezoidal distortion correction unit 136, the image displayed on the light modulation device 130 is deformed so as to correct the trapezoidal distortion.

  When a signal corresponding to the projection distance is input from the CPU 120, the lens driving unit 155 drives the focus adjustment motor 157 based on this signal to perform focus adjustment.

The RAM 160 forms a work area for temporarily storing programs executed by the CPU 120 and data. Note that the video processor 134 includes a work area necessary for executing each process, such as an image display state adjustment process performed by itself, as a built-in RAM.
In addition, the ROM 170 stores a program executed by the CPU 120 to realize each processing unit described above, data related to the program, and the like. The ROM 170 stores adjustment image data to be projected on the screen SC in a trapezoidal distortion correction process, which will be described later, in the adjustment image storage unit 171.

  The operation unit 195 is provided in the main body of the projector 100 and includes various operators such as a switch for an operation by a user and an indicator lamp. Under the control of the CPU 120, the operation unit 195 appropriately turns on or blinks the indicator lamp according to the operation state or setting state of the projector 100, and outputs an operation signal corresponding to the operation on the operation element. In addition, the remote controller control unit 190 receives a radio signal transmitted from a remote controller 191 outside the projector 100. The remote controller 191 includes an operation element (not shown) operated by a user, and transmits an operation signal corresponding to an operation on the operation element as an infrared signal or a wireless signal using a radio wave of a predetermined frequency. The remote control unit 190 includes a light receiving unit (not shown) that receives an infrared signal and a receiving circuit (not shown) that receives a radio signal. The remote control unit 190 receives a signal transmitted from the remote control 191, analyzes it, and operates by a user. Is generated and output to the CPU 120.

The imaging unit 180 (imaging means) includes a CCD camera 181 using a CCD that is a well-known image sensor. The imaging unit 180 is provided at a position where the CCD camera 181 can image the front surface of the projector 100, that is, the direction in which the projection optical system 150 projects an image toward the screen SC. In the imaging unit 180, the camera direction and the angle of view of the CCD camera 181 are set so that the entire projection image projected on the screen SC at the recommended projection distance falls within at least the imaging range.
The imaging unit 180 performs imaging according to the control of the imaging control unit 122. The imaging unit 180 sets the shutter speed according to the control data input from the imaging control unit 122, and executes imaging with the CCD camera 181 at the timing instructed by the imaging control unit 122 at the set shutter speed.

In addition to the CCD, the CCD camera 181 includes a single focus lens that forms an image on the CCD, a mechanism such as an auto iris that adjusts the amount of light incident on the CCD, and a control circuit that reads a video signal from the CCD. The auto iris mechanism receives a signal corresponding to the accumulated value of the brightness of the image from the CCD camera 181 from the control circuit, and an iris (aperture) provided in the single focus lens so that the accumulated value of brightness falls within a predetermined range. Is automatically adjusted.
The image whose brightness has been adjusted by auto iris is output from the imaging unit 180 to the captured image memory 182 and repeatedly written in a predetermined area of the captured image memory 182. The captured image memory 182 sequentially inverts the flag of a predetermined area when the writing of the image for one screen is completed, so that the imaging control unit 122 refers to this flag to perform imaging using the imaging unit 180. You can know if it is completed. The imaging control unit 122 accesses the captured image memory 182 while referring to the flag, and acquires a necessary captured image.

3A and 3B are explanatory diagrams showing how the image blur detection unit 123 processes a captured image. FIG. 3A illustrates an example of a captured image, and FIG. 3B illustrates how the captured image is divided into a plurality of regions. Indicates.
Since the imaging unit 180 is adjusted so that a larger range than the projection image projected by the projector 100 can be captured, the captured image 220 includes the projection image projected by the projector 100 as shown in FIG. The projected image area 224 and its surroundings. Here, an area where the screen SC is shown is a screen image area 222, and an area where the outside of the screen image area 222 is shown is a background image area 226.

  The image blur detection unit 123 calculates a blur amount in the captured image 220 acquired by the shooting control unit 122 and outputs a value indicating the blur amount. As a specific example, the image blur detection unit 123 converts the data of the captured image 220 into a frequency domain by Fourier transform or the like, and outputs the ratio or amount of high-frequency components included in the captured image 220 as an index of the blur amount. Is mentioned. Further, the maximum value and the minimum value of the luminance data of each pixel of the captured image 220 can be obtained, and the difference between the maximum value and the minimum value can be used as a blur amount index. In general, a sharp image without blurring has a high contrast and a clear outline, so that the difference between the maximum value and the minimum value of luminance data is large. Accordingly, the larger the difference between the maximum value and the minimum value of the luminance data in the captured image 220, the smaller the amount of blur. Therefore, the image blur detection unit 123 calculates the difference between the maximum value and the minimum value of the luminance data. It may be output as a blur amount index, or may be output by converting the difference between the maximum value and the minimum value of the luminance data into a value corresponding to the amount of blur amount.

  The movement determination unit 124 acquires a value that is an index of the amount of blur output from the image blur detection unit 123, and based on the change over time in the value of the blur amount, Determine if you are moving. In order to determine the change in the amount of blur over time, the movement determination unit 124 causes the image blur detection unit 123 to detect the amount of blur for a plurality of images continuously captured by the imaging unit 180, and thereby the plurality of captured images. Compare the amount of blur. Here, the imaging control unit 122 causes the imaging unit 180 to continuously perform imaging a plurality of times. The shooting control unit 122 sets the shooting time interval or cycle in the imaging unit 180 as a value for movement determination processing.

  For example, the movement determination unit 124 determines that the projector 100 is stationary when the amount of blur in the captured image is smaller than a predetermined determination reference value. When the determination is performed more strictly, the projector 100 may be determined to be stationary when the blur amounts of a plurality of consecutive captured images are all smaller than the determination reference value. On the other hand, when the shake amount is equal to or larger than the determination reference value, it is determined that the projector 100 is moving, that is, not stationary. In addition, after determining that the projector 100 is not stationary, when the amount of blur of a plurality of consecutive captured images becomes smaller with time and becomes smaller than the determination reference value, it is determined that the projector 100 is stationary. .

As described above, when the image blur detection unit 123 outputs the difference between the maximum value and the minimum value of the luminance data as a blur amount index, the movement determination unit 124 determines, for example, as follows. When the blur amount (difference between the maximum value and the minimum value of the luminance data) in the captured image is smaller than a preset luminance difference reference value, it is determined that the projector 100 is not stationary. Further, when the shake amount in the photographed image taken before that is equal to or greater than the luminance difference reference value and the shake amount in the latest photographed image is smaller than the luminance difference reference value, the stationary projector 100 starts moving. Can be determined. On the other hand, the amounts of blur in a plurality of consecutive captured images are compared, and if the difference in the amount of blur between the images is smaller than a preset image comparison reference value, it is determined that the projector 100 is stationary. That is, it can be determined that the projector 100 is stationary not only when the absolute amount of blur is small but also when the amount of change over time is small.
Here, the determination reference value, the luminance difference reference value, and the image comparison reference value are set in advance by operating the remote controller 191 or the operation unit 195, or are set when the projector 100 is shipped, and stored in the RAM 160 or the ROM 170. .

  By the way, when the projector 100 is projecting an image, the image in the projected image region 224 changes in the captured image 220 in FIG. 3A, so it may be difficult to compare the amounts of blur in the plurality of captured images. is there. For this reason, it is preferable that the image blur detection unit 123 calculates the blur amount in a portion of the captured image 220 excluding the projection image region 224. In this case, the movement determination unit 124 only determines the value output by the image blur detection unit 123, and whether or not the blur amount includes the projection image region 224 does not affect the operation of the movement determination unit 124.

Furthermore, depending on the installation environment of the projector 100, blurring that is not caused by the movement of the projector 100 may occur. For example, when a person or object passes between the screen SC and the projector 100 and appears in the background image area 226, or a person or object located in the background of the screen SC moves, the person or object moves in the background image area. This is the case when it is reflected in H.226.
The image blur detection unit 123 divides the captured image 220 into a plurality of regions to obtain a blur amount for each region, and the movement determination unit 124 performs determination based on the blur amount for each region.

  For example, as shown in FIG. 3B, the image blur detection unit 123 divides the captured image 220 into four areas A to D, and the blur amount in each of the areas A, B, C, and D is determined. Are calculated individually. The movement determination unit 124 determines whether or not the projector 100 is stationary based on the blur amount of the area A of each captured image 220 when determining the blur amount of the plurality of consecutive captured images 220. Whether or not the projector 100 is stationary is determined based on the amount of blurring, and similarly for the regions C and D, it is determined whether or not the projector 100 is individually stationary.

Then, when it is determined that the projector 100 is not stationary only in some areas and the projector 100 is determined to be stationary in other areas, as a final determination, the projector 100 is stationary. It is determined that For example, when it is determined that the projector 100 is not stationary as a result of the determination based only on the blur amount of the region A, and the projector 100 is determined to be stationary in the determinations for the regions B to D, the projector It is determined that 100 is stationary. In other words, the determination result that the projector 100 is moving is output only when it is determined that the projector 100 is not stationary for each of the areas A to D.
Even if a person or an object moves within the imaging range of the CCD camera 181 as in the above example, it is unlikely that the person or object moves over all the areas A to D within the shutter opening time of one imaging. That is, when the projector 100 is stationary, the amount of blur does not increase in all regions even though the amount of blur increases only in a part of the regions A to D in one captured image 220. Therefore, by dividing the captured image 220 and detecting the amount of blur and determining the movement, the influence of the change in the captured image 220 that is not caused by the movement of the projector 100 can be eliminated and the projector 100 can be accurately stopped. Can be determined.
In addition, when the projector 100 is projecting an image, the image blur detection unit 123 divides the captured image 220 into a plurality of regions A to D, and the image blur detection unit 123 excludes the projection image region 224 from each region. It is preferable to calculate the shake amount.

Next, the operation of the projector 100 will be described.
4 to 6 are flowcharts showing the operation of the projector 100, FIG. 4 shows the overall operation, FIG. 5 shows the movement determination process shown in step S13 of FIG. 4, and FIG. 6 shows the step of FIG. The trapezoidal distortion correction process shown in S14 will be described in detail.
When the power is turned on, the projection control unit 121 of the projector 100 starts projecting a projection image based on a video signal input from the outside (step S11), and is operated by operating the remote controller 191 or the operation unit 195. When the execution of the setup is instructed (step S12), the photographing control unit 122, the image blur detection unit 123, and the movement determination unit 124 are controlled to execute a movement determination process (step S13). This movement determination process is a process for determining whether the projector 100 is stationary or moving relative to the screen SC. When it is determined in this movement determination process that the projector 100 is stationary, the projector 100 proceeds to the next step S14.

Here, the details of the movement determination process will be described with reference to FIG. In the following description, the image blur detection unit 123 outputs the difference between the maximum value and the minimum value of the luminance data in the captured image as the blur amount value, and the movement determination unit 124 determines based on the blur amount value. An example of performing is described.
When the projection control unit 121 instructs the start of the movement determination process, the shooting control unit 122 sets shooting conditions for shake detection for the imaging unit 180 (step S21). The shooting conditions set here include at least the shutter speed, and are set so that the shutter opening time is longer than the shooting conditions in the trapezoidal distortion correction process described later. Further, the shooting condition may include a zoom magnification, and is set so that, for example, the captured image is captured to the outside of the screen SC.

Next, the imaging control unit 122 causes the imaging unit 180 to perform imaging in accordance with the set imaging conditions (step S22), and acquires captured image data from the captured image memory 182 (step S23).
Thereafter, the image blur detection unit 123 starts a blur detection process for detecting the blur amount of the captured image (step S24). The image blur detection unit 123 divides the captured image according to a preset division method (step S25).

The image blur detection unit 123 selects, as a processing target, one of the plurality of divided regions that has not been processed (step S26), and obtains the maximum value and the minimum value of the luminance data in the selected region. At the same time, the difference is calculated (step S27), and the difference value (calculated value) between the calculated maximum value and minimum value is stored in the RAM 160 (step S28).
Next, the movement determination unit 124 determines whether or not the calculated value obtained by the image blur detection unit 123 for the previously captured image is stored in the RAM 160 (step S29), and the previous calculated value is stored. If not (step S29; No), the image blur detection unit 123 determines whether there is an unprocessed area among the areas of the captured image divided (step S30). If there is an unprocessed area (step S30; Yes), the process returns to step S26 to select an area to be processed next. When there is no unprocessed area (step S30; No), the process proceeds to step S36 described later.

  On the other hand, when the previous calculated value calculated by the image blur detection unit 123 is stored in the RAM 160 (step S29; Yes), the movement determination unit 124 calculates the calculated value related to the previously captured image and the calculated value in step S27. The calculated value is compared (step S31), and it is determined whether or not the condition when the projector 100 starts moving from the stationary state is satisfied (step S32). The condition when the movement is started is, for example, that the calculated value calculated this time in step S27 is smaller than the luminance difference reference value, or that the calculated value becomes smaller with time, and the previous calculated value is the luminance difference. It is mentioned that the calculated value is smaller than the reference value and the calculated value is smaller than the reference value.

  When the condition when the projector 100 starts moving from the stationary state is satisfied (step S32; Yes), the movement determination unit 124 sets a movement start flag in association with the region to be processed (step S33). ), The process proceeds to step S30. The movement start flag is stored in the RAM 160 for each area obtained by dividing the captured image. The movement determination unit 124 determines whether or not there is an unprocessed area in step S30. If there is an unprocessed area, the movement determination unit 124 returns to step S26 to select the next area. Migrate to

When the projector 100 does not meet the condition when the movement starts from the stationary state (step S32; No), the movement determination unit 124 determines whether or not the condition when the projector 100 is stationary is satisfied (step S32; No). Step S34). The condition when the camera is stationary is, for example, that the calculated value calculated this time in step S27 and the previously calculated value are both larger than the luminance difference reference value, or the difference between the previous and current calculated values is preset. It is mentioned that it is smaller than the image comparison reference value.
If the condition when the projector 100 is stationary (step S34; Yes), the movement determination unit 124 sets a stationary flag in association with the area to be processed (step S35), and the process proceeds to step S30. To do. The still flag is stored in the RAM 160 for each area obtained by dividing the captured image. In addition, when the condition when the projector 100 is stationary is not satisfied (step S34; No), the movement determination unit 124 proceeds to step S30.
In step S30, the movement determination unit 124 determines whether there is an unprocessed area. If there is an unprocessed area, the process returns to step S26 to select the next area, and if there is no unprocessed area, step S36. Migrate to

  In step S36, it is determined whether or not it is possible to determine whether the projector 100 is stationary based on the shake amount. If there is no previous calculated value in step S29, it is determined that the determination cannot be made (step S36; No), and the process returns to step S22 to process the next captured image data. If the determination is possible (step S36; Yes), the movement determination unit 124 acquires the movement start flag and the stationary flag of each area stored in the RAM 160, and finally the projector 100 stops. It is determined whether or not there is (step S37). When it is determined that the projector 100 is stationary (step S37; Yes), the projector 100 returns to FIG. 4 and starts the trapezoidal distortion correction process in step S14. Also. If it is determined that the projector 100 is not stationary (step S37; No), the process returns to step S22 to execute the next captured image.

  As described above, when it is determined that the projector 100 is stationary relative to the screen SC, the projection control unit 121 executes trapezoidal distortion correction processing (step S14 in FIG. 4). In the trapezoidal distortion correction process, it is necessary to detect the shape of the projection image currently projected on the screen SC. However, if the projector 100 is not stationary, it may be difficult to accurately detect the shape of the projection image. . For this reason, the projection control unit 121 executes the trapezoidal distortion correction process after determining that the projector 100 is stationary by the movement determination process. By this trapezoidal distortion correction processing, the projection image projected on the screen SC is corrected for deformation due to the projection projection angle of the projector 100, and becomes almost the original shape.

Here, the trapezoidal distortion correction processing will be described in detail with reference to FIG.
When the projection control unit 121 instructs the start of trapezoidal distortion correction processing, the imaging control unit 122 sets imaging conditions for trapezoidal distortion correction processing for the imaging unit 180 (step S41). The shooting conditions set here include at least the shutter speed, and are set so that the shutter opening time is shorter than the shooting conditions during the movement determination process. Further, the shooting condition may include a zoom magnification. For example, the shooting condition includes a range in which the projected image is formed on the screen SC, and is set so that a smaller range than that in the movement determination process is reflected in the captured image.

Next, the projection control unit 121 controls the video processor 134 to read out the adjustment image stored in the adjustment image storage unit 171, and outputs the adjustment image together with the command to the video processor 134. The image is displayed on the liquid crystal panel of the modulation device 130 and projected onto the screen SC (step S42). Here, when the projection of the input image already input from the A / D conversion unit 110 to the video processor 134 has been started, the projection control unit 121 adjusts after stopping the display of the input image. Project images.
Thereafter, in a state where the adjustment image is projected on the screen SC, the imaging control unit 122 causes the imaging unit 180 to perform imaging according to the set imaging conditions, and acquires captured image data from the captured image memory 182 (step S43). ).

The projection control unit 121 controls the three-dimensional surveying unit 125 and the projection angle calculation unit 126 to calculate parameters for correcting trapezoidal distortion based on the captured image captured during the projection of the adjustment image ( Step S44).
In step S44, the three-dimensional surveying unit 125 displays the three-dimensional state of the plane including the screen SC in the three-dimensional coordinate system (hereinafter also referred to as “lens coordinate system”) having the origin of the principal point of the zoom lens 152 of the projector 100. 3D survey processing to detect That is, the three-dimensional inclination of the screen SC with respect to the optical axis of the projection optical system 150 in the projector 100 is detected. In this process, the captured image acquired from the captured image memory 182 is discretized, and the centers of 16 squares included in the captured image are obtained as measurement points. Then, the three-dimensional surveying unit 125 selects three points that can define a plane from the measurement points, detects the three-dimensional coordinates in the lens coordinate system of the three selected measurement points, and determines the tertiary of the detected three measurement points. Based on the original coordinates, an approximate plane that approximates the plane including the screen SC is calculated. Subsequently, the projection angle calculation unit 126 calculates a projection projection angle that is an angle between the approximate plane of the screen plane detected by the three-dimensional surveying process and the optical axis of the projection light projected from the projector 100. Further, the projection angle calculation unit 126 obtains the corrected image shape in the displayable area of the liquid crystal panel of the light modulation device 130 based on the calculated projection projection angle, and the image before correction in the displayable area of the liquid crystal panel. A conversion coefficient (parameter) for converting the shape into a corrected image shape is calculated.

  Subsequently, the projection control unit 121 sets the obtained parameters in the trapezoidal distortion correction unit 136, and causes the trapezoidal distortion correction unit 136 to perform trapezoidal distortion correction (step S45). The trapezoidal distortion correction unit 136 converts the input digital signal using the set parameters, and outputs the converted result to the light modulation device driving unit 132. That is, the trapezoidal distortion correction unit 136 repeats vector calculation for the coordinates of each pixel with respect to the digital signal input from the A / D conversion unit 110, and displays an image to be displayed on the liquid crystal panel of the light modulation device 130. Deform to correct keystone distortion. During the trapezoidal distortion correction, an image that is deformed into a substantially trapezoid defined by the above parameters is displayed in a displayable range of the liquid crystal panel that is normally rectangular so as to correct the deformation of the projected image on the screen SC. The projection control unit 121 ends the trapezoidal distortion correction process and proceeds to step S15 in FIG.

After the trapezoidal distortion correction process is completed, in step S15, the projection control unit 121 starts the movement determination process by the image blur detection unit 123 and the movement determination unit 124 again. This movement determination process is continuously executed while an input image is projected.
The projection control unit 121 starts projection of the input image by the video processor 134 (step S16), and constantly monitors the determination result of the movement determination process started in step S15 (step S17). When it is determined in this movement determination process that the projector 100 is not stationary (step S17; No), the projection control unit 121 returns to step S13 and executes the movement determination process and the trapezoidal distortion correction process.
Further, while the projector 100 is stationary, it is determined whether or not the projection end is instructed by the operation of the remote controller 191 or the operation unit 195 (step S18). When the projection is not terminated (step S18; No), In step S17, projection is continued. When the end of projection is instructed by the operation of the remote controller 191 or the operation unit 195 (step S18; Yes), the projection control unit 121 ends the projection and shifts to a standby state or a stop state.

  As described above, the projector 100 according to the embodiment to which the present invention is applied projects an image on the screen SC, and captures an image including the projection image projected on the screen SC. An image blur detection unit 123 that detects blur in the captured image, and a movement determination unit 124 that determines the movement of the projector 100 relative to the screen SC based on the detection result of the image blur detection unit 123. It is possible to determine whether or not the projector 100 is moving with respect to the screen SC, etc., while having a configuration that does not have sensors for detecting movement. Thus, it is possible to reduce the number of parts while maintaining the function of detecting the movement of the projector 100 with respect to the screen SC, and it is possible to reduce the size.

  The projector 100 also projects the illumination optical system 140, the light modulation device 130 that modulates the light emitted from the illumination optical system 140 based on the input image, and the light modulated by the light modulation device 130 onto the screen SC. The trapezoidal distortion of the projection image projected on the screen SC is detected on the basis of the captured image captured by the optical system 150 and the imaging unit 180, and the input image of the light modulation device 130 is processed, thereby the trapezoidal distortion of the projection image. Since the movement of the projector 100 can be determined using the imaging unit 180 that captures the screen SC in order to correct the trapezoidal distortion, the number of parts can be reduced.

  The projector 100 also includes a shooting control unit 122 that controls the shutter speed of the imaging unit 180. When the shooting control unit 122 captures a shot image for detecting a blur by the image blur detection unit 123, and a trapezoidal distortion. Since the shutter speed of the imaging unit 180 is set to a different speed when shooting a captured image for detecting the trapezoidal distortion by the correction unit 136, it is suitable for correcting the trapezoidal distortion using the common imaging unit 180. A photographed image and a photographed image suitable for shake detection can be obtained, and different processes of trapezoidal distortion correction and shake detection can be performed with high accuracy.

  Further, when the movement determining unit 124 determines that the movement of the projector 100 with respect to the screen SC is small under the control of the projection control unit 121, the projector 100 causes the trapezoidal distortion correcting unit 136 to perform correction, and the trapezoidal distortion correcting unit 136. After the correction by (1) is completed, the blur detection by the image blur detection unit 123 and the determination by the movement determination unit 124 are started. Thus, by correcting the trapezoidal distortion under a preferable condition by performing the trapezoidal distortion correction after the movement of the projector 100 becomes small, a trapezoidal distortion correcting operation in which an effect cannot be expected while the projector 100 is moving is performed. It can avoid and achieve efficient control. In addition, since the movement of the projector 100 is determined after the trapezoidal distortion correction is performed, it can be easily determined whether or not the keystone distortion correction is necessary again, and the trapezoidal distortion correction is performed as necessary to visually recognize the projected image. Can keep sex.

  In addition, the image blur detection unit 123 extracts a plurality of regions from the captured image captured by the imaging unit 180 and detects blur for each region, and the movement determination unit 124 detects each of the images detected by the image blur detection unit 123. Since the movement of the projector 100 with respect to the screen SC is determined by comparing the blurring of the areas, it is possible to prevent an erroneous determination due to a blur that is not caused by the movement of the projector 100 and to perform the movement determination with high accuracy and efficiency.

  The above-described embodiment is merely an example of a specific mode to which the present invention is applied, and the present invention is not limited. The present invention can be applied as a mode different from the above-described embodiment. For example, in the above embodiment, the projector 100 installed in front of the screen SC has been described as an example of a configuration in which an image is projected forward. However, the present invention is not limited to this and the screen SC is transmissive. Of course, the present invention can be applied to a configuration in which the projector 100 projects an image from the back side of the screen SC. In the above embodiment, the image blur detection unit 123 converts the captured image into the frequency domain and calculates the blur amount based on the ratio and amount of the high frequency component, and the maximum value and the minimum value of the luminance data of the captured image. However, the present invention is not limited to this, and the relative position between the screen SC and the projector 100, specifically, the screen SC and the CCD camera 181 is described. Any processing may be used as long as it is a method that can quantify the blurring of the photographed image caused by the change in.

In the above embodiment, the imaging unit 180 is described as having a CCD camera 181 including a CCD image sensor. However, the present invention is not limited to this, and a CMOS sensor is used as the image sensor of the imaging unit 180. It may be used.
Furthermore, the control program and setting data stored in the ROM 170 in the above embodiment can be stored in a portable recording medium, and connected to the projector 100 via a communication network. Alternatively, the projector 100 may be stored so that it can be downloaded from another device.
Further, each functional unit of the projector 100 illustrated in FIG. 2 indicates a functional configuration, and a specific mounting form is not particularly limited. That is, it is not always necessary to mount hardware corresponding to each function unit individually, and it is of course possible to adopt a configuration in which the functions of a plurality of function units are realized by one processor executing a program. In addition, in the above embodiment, a part of the function realized by software may be realized by hardware, or a part of the function realized by hardware may be realized by software. In addition, the specific detailed configuration of the projector 100 can be arbitrarily changed without departing from the gist of the present invention.

  DESCRIPTION OF SYMBOLS 100 ... Projector, 120 ... CPU, 121 ... Projection control part (operation control means), 122 ... Shooting control part (shooting control means), 123 ... Image blur detection part (blur detection means), 124 ... Movement determination part (movement determination) Means), 125 ... three-dimensional surveying part, 126 ... projection angle calculation part, 130 ... light modulation device (modulation means), 132 ... light modulation device drive part, 136 ... trapezoidal distortion correction part (trapezoidal distortion correction means), 140 ... Illumination optical system (light source), 150 ... projection optical system (projection means), 170 ... ROM, 171 ... image storage unit for adjustment, 180 ... image pickup part (image pickup means), 220 ... photographed image, SC ... screen (projection surface) .

Claims (5)

A projector that projects an image on a projection surface,
A light source;
Modulation means for modulating light emitted from the light source based on an input image;
Projection means for projecting the light modulated by the modulation means onto the projection surface;
Imaging means for capturing a range including an image projected on the projection surface;
A shake detection means for detecting a shake in a captured image taken by the imaging means;
Based on the detection result of the shake detection unit, a movement determination unit that determines the movement of the projector relative to the projection surface;
A trapezoid that detects trapezoidal distortion of a projected image projected on the projection surface based on a captured image captured by the imaging unit and corrects the trapezoidal distortion of the projected image by processing an input image of the modulating unit. Distortion correction means;
Photographing control means for controlling the shutter speed of the imaging means,
The photographing control means includes a case where the photographed image for detecting blur is photographed by the shake detecting means and a case where the photographed image for detecting trapezoidal distortion is photographed by the trapezoidal distortion correcting means. A projector characterized in that the shutter speed of the imaging means is set to a different speed . The photographing control means has a shutter speed when photographing the photographed image for detecting blur by the blur detecting means, and a shutter speed when photographing the photographed image for detecting trapezoidal distortion by the trapezoidal distortion correcting means. The projector according to claim 1 , wherein the projector is set to be longer than a shutter speed. When it is determined that the movement of the projector relative to the projection surface is small by the movement determination unit, the trapezoidal distortion correction unit performs correction,
3. The projector according to claim 1, further comprising an operation control unit that starts shake detection by the shake detection unit and determination by the movement determination unit after correction by the trapezoidal distortion correction unit is completed. The blur detection unit extracts a plurality of regions from the captured image captured by the imaging unit, detects a blur for each region,
The movement determination means, by comparing the blur of each region in which the shake detection unit detects, according to any one of claims 1 to 3, characterized in that to determine the movement of the projector relative to the projection surface projector. A method of controlling a projector that projects an image on a projection surface,
The range including the image projected on the projection surface is photographed by the imaging means ,
Detecting blur in a captured image captured by the imaging means ;
Based on the detection result of the shake, to determine the movement of the projector relative to the projection surface,
Based on the captured image captured by the imaging means, the trapezoidal distortion of the image projected on the projection surface is detected and corrected,
Setting the shutter speed of the imaging means to a different speed when shooting the shot image for detecting the blur and when shooting the shot image for detecting the trapezoidal distortion ;
A projector control method characterized by the above.

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