JP6439254B2 - Image projection apparatus, control method for image projection apparatus, and control program for image projection apparatus - Google Patents

Description

  The present invention relates to an image projection apparatus, a control method for the image projection apparatus, and a control program for the image projection apparatus. More specifically, the present invention relates to autofocus control of an image projection apparatus.

  In recent years, the chances of giving presentations using a huge screen to a large number of people at lectures and educational sites have increased remarkably. In particular, a projector widely known as an image projection apparatus has been improved in the resolution, the price, and the like due to the higher resolution of the liquid crystal panel, the higher efficiency of the light source lamp. In addition, for example, small and light image projectors using DMD (Digital Micro-mirror Device) have become widespread, and these image projectors are widely used not only at offices and schools but also at home.

  In such a method for adjusting the focus of a projected image in an image projection apparatus, the image projection apparatus includes an imaging unit, and a predetermined adjustment image (calibration pattern) is projected onto a screen as a projection surface, and the imaging unit takes an adjustment. It is known to perform autofocusing (hereinafter also referred to as AF) by adjusting the illumination optical system based on the difference in gradation of the image for use.

  For example, Patent Document 1 discloses an adjustment image generation unit that generates an adjustment image for adjusting the focus of a projection image displayed on a projection surface, and an adjustment image projected on the projection surface. And an adjustment image generating unit that generates an adjustment image to be generated so that the gradation pattern of the imaging adjustment image obtained by imaging approaches the gradation pattern of the adjustment image. A projector to change is disclosed. In the technique described in Patent Document 1, the influence of the projection state of the projector at the start of focus adjustment is suppressed, and the accuracy of focus adjustment is improved.

  However, in a method in which an image for adjustment is picked up by a conventional image pickup means and autofocus is performed based on the image, if there is a pattern or dirt on the projection surface on which the image for adjustment is projected, a reference difference in gradation is set. There was a problem that the accuracy of autofocus deteriorated because it could not be specified.

  Therefore, the present invention captures an image of a projection surface by an imaging unit, detects a region suitable for projection of the adjustment image on the projection surface, and performs focus adjustment based on the adjustment image projected on the region. Accordingly, an object of the present invention is to provide an image projection apparatus capable of improving the accuracy of autofocus.

  In order to achieve such an object, an image projection apparatus according to the present invention generates a projection image based on a video signal, and captures an image of the projection surface in an image projection apparatus that projects the projection image onto the projection surface. And color distribution information detection means for detecting color distribution information of the projection surface based on an image captured by the imaging means and determining whether or not it is a projectable area of an adjustment image used for focus control Adjustment image projecting means for projecting the adjustment image onto the projectable area of the adjustment image detected by the color distribution information detecting means; and the image capturing means for projecting the adjustment image projected on the projection surface Focus control means for adjusting the illumination optical system based on the picked-up image picked up by the above.

  According to the present invention, the autofocus accuracy of the image projection apparatus can be improved.

It is a schematic block diagram which shows an example of an image projection system. It is a block diagram which shows the structure of an image projector. It is explanatory drawing of a color distribution information detection process. It is explanatory drawing of the projection process of the image for adjustment. It is a flowchart of the autofocus control by an image projector.

  Hereinafter, the configuration according to the present invention will be described in detail based on the embodiment shown in FIGS.

  An image projection apparatus according to the present embodiment generates a projection image (projection image 202) based on a video signal, and projects the projection image onto a projection surface (screen 200) (image projection apparatus 100). An image pickup means (camera 103) for picking up an image to be projected, and color distribution information on the face to be projected is detected based on an image taken by the image pickup means, and an adjustment image (AF pattern 206) used for focus control is projected. A color distribution information detection unit (color distribution information detection unit 110) for determining whether or not the image is an available region, and an adjustment image for projecting the adjustment image onto the projectable region of the adjustment image detected by the color distribution information detection unit. The illumination optical system (illumination optical system 107) is adjusted based on the image projection unit (adjustment image projection unit 111) and a captured image obtained by imaging the adjustment image projected on the projection surface by the imaging unit. A point control unit (focus control unit 112), those having a. In addition, the code | symbol in embodiment and an application example are shown in a parenthesis.

(Image projection system configuration)
FIG. 1 is a schematic configuration diagram illustrating an example of an image projection system 300. The image projection system 300 includes an image projection device (projector) 100 and a video supply device 150, and the image projection device 100 and the video supply device 150 are connected by a cable 160.

  The image projection device 100 is an image output device that projects an image provided by the video supply device 150 onto a projection surface such as a screen 200. In addition to the image provided by the video supply device 150, the image projection device 100 projects an OSD screen (superimposed image) such as a menu screen that allows the user to specify various operations. The OSD screen is also projected when no image is provided from the video supply device 150.

  The image projection apparatus 100 has, as an interface for inputting a video signal, a VGA (Video Graphics Array) input terminal such as a D-Sub connector, an HDMI (registered trademark) (High-Definition Multimedia Interface) terminal, an RGB terminal, a DisplayPort terminal, an S An input terminal such as a VIDEO terminal or an RCA terminal is provided, and a video signal is received from the video supply device 150 via a cable 160 connected to these terminals. Note that the image projection apparatus 100 may receive a video signal from the video supply apparatus 150 by wireless communication based on a wireless communication protocol such as Bluetooth (registered trademark) or WiFi (registered trademark).

  The video supply device 150 is a device that provides an image to be projected by the image projection device 100. The video supply device 150 includes an interface that outputs a video signal, and an image projection device that transmits a video signal forming a display image of the video supply device 150 at a predetermined transfer rate (for example, 30 fps (frame per second) to 60 fps). To 100.

  Similarly, the video supply device 150 includes an output terminal such as a VGA output terminal or an HDMI terminal as an interface for outputting a video signal, and transmits the image signal to the image projection device 100 via a cable 160 connected to these terminals. Can do. Note that the video supply device 150 may transmit a video signal to the image projection device 100 by wireless communication.

  As the video supply device 150, for example, a notebook PC (information processing device) can be used, but a device capable of supplying video signals such as a desktop PC, a tablet PC, a PDA, a DVD player, and a Blu-ray disc player is used. Can be applied. In the example shown in FIG. 1, one video supply device 150 is connected to the image projection device 100, but the image projection device 100 can connect two or more video supply devices 150. In addition, a plurality of image projection apparatuses 100 are connected to one video supply apparatus 150, and images are projected onto different projection areas on the screen 200, and a single image is projected by combining the projected images. A multi-projection system may be used.

  Further, as shown in FIG. 1, the image projection apparatus 100 includes a camera 103 as an imaging unit and an illumination optical system 107, and projects a projection image 202 on a screen 200.

  In the example shown in FIG. 1, a gray area 204 and a white area 205 exist in an area on the screen 200 on which the projection image 202 is projected (referred to as a projection area 203). Here, it is assumed that the gray area (gray area 204) indicates a dirty area on the screen 200, and the other white area (white area 205) is an area without dirt. In the present embodiment, an example in which the screen 200 is white will be described.

  Here, it is assumed that the field of view (imaging range 201) by the camera 103 included in the image projection apparatus 100 is at least larger than the projection region 203. Therefore, the entire area of the projection image 202 can be captured by the camera 103. In FIG. 1, the dotted arrow 103 a indicates the optical path of the camera 103, and the solid arrow 107 a indicates the optical path of the projection light from the illumination optical system 107.

(Configuration of image projector)
FIG. 2 is a block diagram illustrating a configuration of the image projection apparatus 100 according to the present embodiment.

  The image projection apparatus 100 includes an input interface unit 101, an image processing circuit 102, a camera 103, a camera control circuit 104, a main control unit 105, an operation unit 106, an illumination optical system 107, and an illumination optical system drive circuit. 108.

  The input interface unit 101 is a terminal unit that is connected to a video supply device 150 that supplies an image to the image projection device 100 via a cable 160. As described above, an HDMI terminal or the like is provided and a video signal is received.

  The image processing circuit 102 converts the input video signal into predetermined video data (for example, RGB digital video data) and transfers it to the main control unit 105.

  Here, the main control unit 105 transmits and receives control signals to and from the above-described units, and also includes a CPU (Central Processing Unit) that is a main processor, various control programs, adjustment images for autofocus control, and the like. A ROM (Read Only Memory) that stores data, a memory device (eg, SDRAM (Synchronous Dynamic Random Access Memory) etc.) that temporarily stores data in each process, and setting information etc. are recorded even when the power is turned off. An NVRAM (Non Volatile RAM) which is a data holding memory device to be stored is connected by a bus.

  Further, the main control unit 105 detects the color distribution information of the projection area 203 on the screen 200 based on the image captured by the camera 103, and determines whether or not the adjustment image can be projected in the focus control. The color distribution information detection unit 110 to be determined, the adjustment image projection unit 111 that projects the adjustment image onto the projectable region of the adjustment image, and the captured image obtained by capturing the adjustment image projected on the screen 200 with the camera 103 And a focus control unit 112 for adjusting the illumination optical system 107 based on the above.

  The main control unit 105 also causes the illumination optical system driving circuit 108 to display the video data transferred from the image processing circuit 102.

  The illumination optical system drive circuit 108 controls the illumination optical system 107 based on the control from the main control unit 105 to project the projection image 202. The illumination optical system 107 includes a liquid crystal light valve, a color wheel, a DMD (Digital Micromirror Device), and the like, a mirror (reflection optical system) that reflects video light for displaying images and videos on the screen 200, and enlargement / reduction. Lens (projection optical system).

  The operation unit 106 receives various operation requests from the user, and is configured by key buttons (main body keys) provided on the outer surface of the image projection apparatus 100. When receiving the operation request, the operation unit 106 notifies the main control unit 105 of the operation request. Further, the operation unit 106 receives an operation signal from a remote controller that is a remote operation device, and notifies the main control unit 105 of the operation signal.

  The main body and the remote control are provided with a power key for turning on / off the power of the image projection apparatus 100, a menu key for performing various settings, a cross key, a determination key, an input key for switching input signals, and the like. Note that video data at the time of various settings and input switching is formed by OSD processing by the main control unit 105.

  The camera 103 is an imaging unit that can image at least the entire projection region 203 on the screen 200. For example, it is provided on the projection lens side surface of the image projection apparatus 100 and images the front of the image projection apparatus 100. The camera 103 is controlled by the camera control circuit 104.

  In the image projection apparatus 100 described above, when the projection image 202 is captured by the camera 103, the captured image is transmitted from the camera control circuit 104 to the main control unit 105, and the color distribution information detection unit 110 of the main control unit 105 Then, color distribution information detection processing described later is performed. Further, the adjustment image projection unit 111 of the main control unit 105 performs an adjustment image projection process, which will be described later, according to the result of the color distribution information detection process, so that the AF adjustment image is placed in an optimum area on the screen. Process as projected.

  After the adjustment image is projected on the screen 200 in this way, the adjustment image is captured by the camera 103. Based on the captured image obtained from the camera 103, the focus control unit 112 of the main control unit 105 The illumination optical system drive circuit 108 is controlled to adjust the illumination optical system 107 to execute autofocus.

(Color distribution information detection processing)
The color distribution information detection process of the projection area executed by the color distribution information detection unit 110 of the image projection apparatus 100 will be described. Here, the color distribution information is a color distribution state (color information and position information) of the screen 200 calculated based on a captured image obtained by capturing the projection area 203 on the screen 200 on which the projection image 202 is projected. Say.

  In the present embodiment, it is assumed that the screen 200 is white in a state where there is no dirt or the like, and a portion where a white level (also referred to as a white level) is a predetermined level or higher is detected in the projection region 203 on the screen 200.

  In the color distribution information detection process, the white level is determined based on the value of color information (such as RGB) of each pixel of the image data of the captured image captured by the camera 103. For example, in the case of the RGB color system, white is represented by R = 255, G = 255, and B = 255. For this value, a predetermined threshold (reference value) is set, and the color of the screen 200 is set. It is determined whether a certain white level is a strong region or whether there is a stain or the like and a white level is weak. Here, a region with a strong white level is a region suitable for projecting the adjustment image (a projectable region for the adjustment image), and a region with a weak white level is a region not suitable for projecting the adjustment image. (A non-projectable area of the adjustment image).

  FIG. 3 is an explanatory diagram of the color distribution information detection process of the projection area, schematically showing a one-dimensional space (line segment area 207) in a captured image obtained by capturing the projection area 203 with the camera 103, and the one-dimensional It is a graph showing the white level in space. The horizontal axis of the graph shown in FIG. 3 corresponds to the position (space) of the line segment region 207, and the vertical axis represents the intensity of the white level.

  In the color distribution information detection process, the white level for each pixel constituting the line segment region 207 is determined. As shown in FIG. 3, the white level intensity is very low in the gray area 204, and the white level intensity is high in the white area 205. For example, the calculation result of the white level is a white level intensity of Δ204 at a position corresponding to the gray area 204 and a white level intensity of Δ205 at a position corresponding to the white area 205.

  Then, as shown in FIG. 3, a predetermined reference value is set for the white level intensity, and an area corresponding to a pixel exceeding the reference value is defined as a projectable area (white area 205) of the adjustment image having no dirt on the screen 200. Deciding. In addition, the area corresponding to the pixel below the reference value is determined as the non-projectable area (gray area 204) of the adjustment image having the stain on the screen 200.

  So far, it has been described that the white level of the line segment region 207 which is a one-dimensional space is obtained. However, by calculating the white level intensity in the same manner for the entire projection region 203, the two-dimensional space (projection region 203) Measure the white level intensity. Color distribution information on the screen 200 is detected based on the captured image obtained by capturing the projection region 203 in this way. The projection area 203 is divided into a white area 205 and a gray area 204.

  In this embodiment, the white level is calculated for all the pixels of the captured image. However, the white level calculation method is not limited to this. For example, the pixels are thinned out at predetermined intervals. Anyway. Further, it may be divided into regions in units of a predetermined number of pixels, an average value is obtained for each region, and this is compared with a reference value.

  Further, in the present embodiment, it is assumed that the screen 200 is white. However, when the screen 200 is colored (such as a light cream color), it is determined whether or not projection is possible based on the color of the screen 200. In order to make a determination, the reference value range of the color information is determined, and based on this, the projectable area of the adjustment image and the unprojectable area of the adjustment image may be determined.

(Projection of adjustment image)
Next, adjustment image projection processing executed by the adjustment image projection unit 111 of the image projection apparatus 100 will be described.

  FIG. 4 is an explanatory diagram of the adjustment image projection processing, schematically showing the white region 205 and the gray region 204 in a two-dimensional space (captured image) when the projection region 203 is imaged by the camera 103. FIG. 5 is a diagram showing a state in which an adjustment image (AF pattern 206) is projected onto a white region 205.

  In the adjustment image projection process, first, the white area 205 detected in the color distribution information detection process is determined based on the size of the AF pattern 206 that is an adjustment image stored in the storage unit (ROM or the like) of the main control unit 105. It is determined whether or not it is larger. In the color distribution information detection process, when the white area 205 is detected separately at a plurality of positions, the largest white area 205 may be determined.

  In FIG. 4, the horizontal axis represents the horizontal distance X, and the vertical axis represents the vertical distance Y. The captured image of the projection area 203 captured by the camera 103 includes areas corresponding to the gray area 204 and the white area 205. Further, the horizontal distance of the detected white region 205 is indicated as X1, the vertical distance as Y1, the horizontal distance of the AF pattern 206 as ΔX, and the vertical distance as ΔY.

  The adjustment image projection unit 111 determines whether the horizontal distance X1 and the vertical distance Y1 of the white area 205 are larger than the horizontal distance ΔX and the vertical distance ΔY of the AF pattern. 206 is projected, and the focus control unit 112 performs AF control. On the other hand, if it is small, there is no white area 205 of a size that can project the AF pattern 206, and therefore error processing is performed.

  Note that the striped AF pattern 206 shown in FIG. 4 is an example, and the AF pattern 206 as the adjustment image is not limited to this. Also, the AF control method based on the adjustment image executed by the focus control unit 112 is not particularly limited, and a known or new method can be applied.

(Auto focus control)
FIG. 5 is a process flowchart of autofocus control executed by the image projection apparatus 100.

  First, when the power of the image projection apparatus 100 is turned on by the operation unit 106 (S101), the camera control circuit 104 activates the camera 103 (S102).

  Next, the projection image 202 is projected from the illumination optical system 107 of the image projection apparatus 100 (S103). Here, it is determined whether or not AF setting is turned on in the setting of the image projection apparatus 100. The AF setting can be turned on / off from the operation unit 106.

  When the AF setting is on (S104: Yes), the camera 103 images the projection area 203 (S105). Note that, at the moment of imaging of the projection area 203, the projection image 202 is temporarily not projected on the screen 200 by using an AV mute, an internal optical system filter, or the like.

  Next, based on the captured image data, the color distribution information detection process for the projection area described above is executed (S106), and the white area 205 and the gray area 204 are detected.

  Next, an adjustment image projection process is executed (S107). As described above, it is determined whether the size of the detected largest white area 205 is larger on the two-dimensional plane than the AF pattern 206 that is the adjustment image stored in the image projection apparatus 100.

  If the white area 205 is smaller than the AF pattern 206 (S107: No), an error notification is given (S108). The error notification notifies the user that the autofocus control cannot be executed due to the influence of the dirt on the screen, and the process returns to S104. The error notification process is not particularly limited. For example, an error notification may be sent to the user by voice output from a voice output unit included in the image projection apparatus 100, or an error display is displayed on the projection image 202 as an OSD display. You may make it do.

  On the other hand, when the white area 205 is larger than the AF pattern 206 (S107: Yes), the AF pattern 206 is projected into the white area 205, and predetermined autofocus control is executed based on the projected AF pattern 206. (S109).

  According to the image projection apparatus according to the present embodiment described above, the camera 103 images the projection area 203 on the screen 200, calculates the color distribution information (color information and position information) of the projection area 203, and performs adjustment. By detecting an area suitable for projecting an image, projecting an adjustment image onto the area, and performing focus adjustment based on the projected adjustment image, colors caused by disturbances such as screen patterns, dirt, and fluorescent lights It is possible to improve the autofocus accuracy by suppressing the influence of.

  The above-described embodiment is a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

  Note that the color distribution information detection unit 110, the adjustment image projection unit 111, and the focus control unit 112 of the main control unit 105, for example, execute software (control program) executed by the CPU of the main control unit 105 as the image projection apparatus 100. Can be configured by running

100 Image projector (projector)
101 Input Interface Unit 102 Image Processing Circuit 103 Camera (Imaging Means)
104 Camera Control Circuit 105 Main Control Unit 106 Operation Unit 107 Illumination Optical System 108 Illumination Optical System Drive Circuit 110 Color Distribution Information Detection Unit 111 Adjustment Image Projection Unit 112 Focus Control Unit 150 Video Supply Device 160 Cable 200 Screen (Projection Surface)
201 Imaging range 202 Projected image 203 Projected area 204 Gray area (area where adjustment image cannot be projected)
205 White area (area where adjustment image can be projected)
206 AF pattern (adjustment image)
300 Image projection system

JP 2013-187729 A

Claims (5)

In an image projection apparatus that generates a projection image based on a video signal and projects the projection image on a projection surface.
Imaging means for imaging the projection surface;
Projecting an adjustment image used for focus control by detecting color distribution information of the projection surface based on a captured image obtained by imaging the projection surface when the projection image is not projected by the imaging means Color distribution information detecting means for determining whether or not it is a possible region;
Adjustment image projection means for projecting the adjustment image onto the projectable area of the adjustment image detected by the color distribution information detection means;
A focus control unit that adjusts an illumination optical system based on a captured image obtained by capturing the adjustment image projected on the projection surface by the imaging unit;
The adjustment image projecting unit determines whether a projectable area of the adjustment image is an area having a size capable of projecting the adjustment image, and projects the adjustment image when the adjustment image can be projected. When the projection is impossible, the image projection apparatus notifies the outside that the adjustment image cannot be projected.   The image projection apparatus according to claim 1, wherein the projection image is temporarily unprojected when the imaging unit captures the projection surface.   The color distribution information detection unit detects an area where the projection surface is a predetermined white level or more based on a captured image obtained by imaging the projection surface, and the area is set as a projectable area of the adjustment image. The image projection apparatus according to claim 1, wherein In a control method for an image projection apparatus that generates a projection image based on a video signal and projects the projection image onto a projection surface.
An imaging process for imaging the projection surface when the projection image is not projected by an imaging unit;
Color distribution information detection processing for detecting color distribution information of the projection surface based on a captured image obtained by the imaging processing and determining whether or not it is a projectable region of an adjustment image used for focus control;
An adjustment image projection process for projecting the adjustment image onto the projectable area of the adjustment image detected by the color distribution information detection process;
A focus control process for adjusting an illumination optical system based on a captured image obtained by imaging the adjustment image projected on the projection surface by the imaging unit;
In the adjustment image projecting process, it is determined whether a projectable area of the adjustment image is an area having a size capable of projecting the adjustment image, and if the projection is possible, the adjustment image is projected. When the projection is impossible, the control method for the image projection apparatus notifies the outside that the adjustment image cannot be projected.   A program capable of executing the control method according to claim 4 by the image projection apparatus according to any one of claims 1 to 3.