JP5874529B2 - Image projection apparatus and image projection method - Google Patents

Description

  The present invention relates to an image projection apparatus and an image projection method for projecting an image onto a projection medium.

  A projection device is known that drives a display element based on an input image signal and projects an image related to the image signal onto a screen, a wall surface, or the like. In such a projection apparatus, the amount of information that can be projected is limited due to a limitation on the mechanism that defines the projection direction of the projection means included in the projection apparatus or a limitation on the resolution of the display element.

  Therefore, a projection device has been developed that projects an image by reducing the amount of information of the projected image when the resolution of the image related to the input image signal is larger than the resolution of the display element included in the projection device. It was done.

  As a first example, after reducing the resolution of the image related to the input image signal and reducing the size (area) of the projected image to a size (area) that can be projected based on the resolution of the display element. And a projection device that projects the reduced image. Further, as a second example, a projection device that cuts out a partial area from an image related to an input image signal and projects only an image related to the cut out area can be cited. In the latter example of the projection apparatus, there is a projection apparatus that can project an entire image related to an input image signal by so-called scrolling or the like that continuously changes a cut and projected area.

  However, while the projection apparatus according to the first example described above can project the entire image related to the input image signal, the image size reduction process based on the resolution reduction reduces the image size onto the projection target medium. There is a problem that the quality of the displayed image is degraded. From another aspect, it can be said that there is a problem that the high resolution of the input image signal is wasted due to the image size reduction processing.

  Moreover, the projection apparatus of the second example described above can maintain the resolution of the image signal even in the image displayed on the projection medium. However, the projection apparatus of the second example has a problem that the entire image related to the input image signal cannot be projected at a time.

  On the other hand, Patent Document 1 detects the posture and position of the main body, extracts an actual display image to be actually displayed from the original display image based on the detection result, and projects the actual display image. A projector is disclosed in which an area extracted as an actual display image is changed vertically and horizontally in the original display image by moving the projector up and down and left and right. According to the projector of Patent Document 1, the user can appropriately project only an image of an area desired to be projected by adjusting the posture of the main body with respect to the projection medium and the distance to the projection medium. .

JP 2005-43570 A

  However, in Patent Document 1, for example, a projected display image is captured by a CCD (Charge Coupled Device) as an image sensor, and the attitude of the projector is detected. Therefore, the accuracy of attitude detection depends on the content of the display image. There was a problem that there was a risk of it. For example, when a dark screen such as a night scene is projected in a dark room, the posture may not be detected. In addition, since posture detection is performed by analyzing an image captured by a CCD, there is a problem that a delay occurs in reflecting the result of posture detection on a display image.

  The present invention has been made in view of the above, and an object thereof is to project an image having a higher resolution than that of a display element with higher quality.

  In order to solve the above-described problems and achieve the object, the present invention provides a light modulation element that modulates light in pixel units according to image data, a projection unit that projects light modulated by the light modulation element, and a projection unit Changes the projection direction of the projection unit from the first projection direction to the second projection direction based on the minimum variable angle. A projection angle deriving unit for deriving a projection angle between the projection direction changing unit, the first projection direction, and the projection direction changed by the projection direction changing unit; and a storage unit for storing input image data that has been input; When the projection unit projects from the first projection direction to the second projection direction, the image data projected by the projection unit is input image data stored in the storage unit based on the angle of view and the projection angle. Extracted image data obtained by extracting a part of the image And an image clipping unit for generating a constant period, the minimum variable angle, the angle of view, the light modulation element, characterized in that it is determined based on the size in pixels of the effective region for modulating light.

  Further, the present invention provides an angle-of-view derivation step in which a projection unit that projects light modulated by a light modulation element that modulates light in units of pixels according to image data derives an angle of view for projecting light modulated by the light modulation element. And the projection direction changing step for changing the projection direction of the projection unit from the first projection direction to the second projection direction based on the minimum variable angle, the first projection direction, and the projection direction changing step. A projection angle deriving step for deriving a projection angle between the projection direction, a storage step for storing input image data that has been input, and a case where the projection unit projects from the first projection direction to the second projection direction. In addition, as the image data projected by the projection unit, image segmentation that generates segmented image data in which a part of the image of the input image data stored in the storage step is segmented based on the angle of view and the projection angle is generated at a predetermined cycle. Out and a step, the minimum variable angle, the angle of view, the light modulation element, characterized in that it is determined based on the size in pixels of the effective region for modulating light.

  According to the present invention, it is possible to project an image with a higher resolution than that of the display element with higher quality.

FIG. 1 is a schematic diagram illustrating an appearance of an example of a projector device applicable to the first embodiment. FIG. 2 is a schematic diagram illustrating an exemplary configuration for rotationally driving the drum unit. FIG. 3 is a schematic diagram for explaining each posture of the drum portion. FIG. 4 is a block diagram illustrating a configuration example of the circuit unit and the optical engine unit. FIG. 5 is a schematic diagram schematically illustrating a process of extracting image data stored in the memory. FIG. 6 is a schematic diagram illustrating an example of specifying a cutout region when the drum unit is at the initial position. FIG. 7 is a schematic diagram for explaining the setting of the cutout region with respect to the projection angle θ. FIG. 8 is a schematic diagram for explaining the designation of the cutout region when optical zoom is performed. FIG. 9 is a schematic diagram for explaining a case where an offset is given to the projection position of an image. FIG. 10 is a schematic diagram for explaining an image projected onto a vertical plane. FIG. 11 is a schematic diagram for explaining an image projected onto a vertical plane. FIG. 12 is a schematic diagram for explaining memory access control. FIG. 13 is a schematic diagram for explaining memory access control. FIG. 14 is a schematic diagram for explaining memory access control. FIG. 15 is a schematic diagram for explaining memory access control. FIG. 16 is a flowchart of an example showing a flow of processing when projecting an image based on image data in the projector apparatus. FIG. 17 is a diagram for explaining the projection while moving the entire area of the input image data according to the projection angle θ. FIG. 18 is a diagram for explaining a projected image when the projection angle θ changes at a certain high speed. FIG. 19 is a schematic diagram schematically showing how a projection image is projected from the projection lens. FIG. 20 is a diagram for schematically explaining the afterimage phenomenon. FIG. 21 is a diagram illustrating an example of motor control according to the second method for improving the quality of a projected image. FIG. 22 is a diagram showing another example of the drive pulse by the second method for improving the quality of the projected image. FIG. 23 is a diagram for more specifically explaining the projection prohibition period. FIG. 24-1 is a block diagram illustrating a configuration of an example of a projector device that controls lighting of a light source and prohibits projection. FIG. 24-2 is a block diagram illustrating a configuration of an example of a projector device that prohibits projection by switching on / off driving of the display element. FIG. 24-3 is a block diagram illustrating an exemplary configuration of a projector apparatus that prohibits projection by switching between opening and closing of the shutter. FIG. 24-4 is a block diagram illustrating a configuration of an example of a projector device that inserts a black image and prohibits projection. FIG. 25 is a diagram illustrating an example of the appearance of the projector device according to the second embodiment. FIG. 26 is a diagram illustrating an example of the appearance of a pedestal of the projector device according to the second embodiment. FIG. 27 is a view of the turntable of the projector device according to the second embodiment as viewed from the back side. FIG. 28 is a schematic diagram schematically illustrating an example of a relationship between input image data and projection image data according to the second embodiment.

  Hereinafter, preferred embodiments of an image projection apparatus and an image projection method according to the present invention will be described with reference to the drawings. Specific numerical values and appearance configurations shown in the embodiments are merely examples for facilitating understanding of the present invention, and do not limit the present invention unless otherwise specified. Detailed explanation and illustration of elements not directly related to the present invention are omitted.

<First Embodiment>
<Appearance of image projector>
FIG. 1 is a diagram showing an example of the appearance of an image projection apparatus (projector apparatus) 1 according to the first embodiment of the present invention. 1A is a perspective view of the projector device 1 viewed from the first surface side where the operation unit is provided, and FIG. 1B is a perspective view of the projector device 1 viewed from the second surface side facing the operation unit. FIG. The projector device 1 includes a drum unit 10 and a base 20. The drum unit 10 is a rotating body that can be rotationally driven with respect to the base 20. The base 20 includes a support unit that rotatably supports the drum unit 10, and a circuit unit that performs various controls such as rotation drive control and image processing control of the drum unit 10.

  The drum unit 10 is rotatably supported by a rotation shaft (not shown) made of a bearing or the like provided inside the side plate parts 21a and 21b that are a part of the base 20. Inside the drum unit 10, a light source, a display element that modulates light emitted from the light source according to image data, a drive circuit that drives the display element, and an optical system that projects the light modulated by the display element to the outside And an optical engine section including a cooling means using a fan or the like for cooling the light source or the like.

  The drum unit 10 is provided with windows 11 and 13. The window part 11 is provided so that the light projected from the projection lens 12 of the optical system described above is irradiated to the outside. The window 13 is provided with a distance sensor that derives the distance to the projection medium using, for example, infrared rays or ultrasonic waves. In addition, the drum unit 10 includes an intake / exhaust port 22a for performing intake / exhaust for heat dissipation by the fan.

  Inside the base 20, various substrates and power supply units of the circuit unit, a driving unit for rotationally driving the drum unit 10, and the like are provided. The rotation driving of the drum unit 10 by this driving unit will be described later. On the first surface side of the base 20, the projector device 1 uses an operation unit 14 for a user to input various operations to control the projector device 1 and a remote control commander (not shown). And a receiving unit 15 for receiving a signal transmitted from the remote control commander when the remote control is performed. The operation unit 14 includes various operators that receive user operation inputs, a display unit for displaying the state of the projector device 1, and the like.

  Intake and exhaust ports 16a and 16b are provided on the first surface side and the second surface side of the base 20, respectively, and are driven to rotate so that the intake and exhaust ports 22a of the drum portion 10 face the base 20 side. Even when taking the above, intake or exhaust can be performed so as not to lower the heat radiation efficiency in the drum unit 10. The intake / exhaust port 17 provided on the side surface of the casing performs intake / exhaust for heat dissipation of the circuit unit.

<Drum section rotation drive>
FIG. 2 is a diagram for explaining the rotational driving of the drum unit 10 by the driving unit 32 provided on the base 20. FIG. 2A is a diagram illustrating a configuration of the drum 30 in a state where the cover of the drum unit 10 and the like are removed, and the driving unit 32 provided on the base 20. The drum 30 is provided with a window portion 34 corresponding to the window portion 11 and a window portion 33 corresponding to the window portion 13. The drum 30 has a rotating shaft 36, and is attached to the bearing 37 using a bearing provided on the support portions 31 a and 31 b by the rotating shaft 36 so as to be rotationally driven.

  On one surface of the drum 30, a gear 35 is provided on the circumference. The drum 30 is rotationally driven through the gear 35 by the drive unit 32 provided in the support unit 31b. The protrusions 46 a and 46 b on the inner peripheral portion of the gear 35 are provided for detecting the start point and the end point of the rotation operation of the drum 30.

  FIG. 2B is an enlarged view for showing the configuration of the drive unit 32 provided on the drum 30 and the base 20 in more detail. The drive unit 32 includes a motor 40, a worm gear 41 that is directly driven by the rotation shaft of the motor 40, gears 42 a and 42 b that transmit the rotation by the worm gear 41, and the rotation transmitted from the gear 42 b to the gear of the drum 30. And a gear group including a gear 43 that transmits to 35. By transmitting the rotation of the motor 40 to the gear 35 by this gear group, the drum 30 can be rotated according to the rotation of the motor 40. As the motor 40, for example, a stepping motor that performs rotation control for each predetermined angle by a drive pulse having a predetermined pulse width can be applied.

  Photo interrupters 51a and 51b are provided for the support portion 31b. The photo interrupters 51a and 51b detect protrusions 46b and 46a provided on the inner periphery of the gear 35, respectively. Output signals from the photo interrupters 51a and 51b are supplied to a rotation control unit 104 described later. In the first embodiment, when the protrusion 46b is detected on the photo interrupter 51a, the rotation control unit 104 determines that the posture of the drum 30 has reached the end point of the rotation operation. Further, when the protrusion 46a is detected on the photo interrupter 51b, the rotation control unit 104 determines that the posture of the drum 30 is the posture that has reached the starting point of the rotation operation.

  Hereinafter, from the position where the protrusion 46a is detected on the photo interrupter 51b to the position where the protrusion 46b is detected on the photo interrupter 51a, the direction in which the drum 30 rotates through the arc having the longer length on the circumference of the drum 30 Is the positive direction. That is, the rotation angle of the drum 30 increases in the positive direction.

  In the first embodiment, the angle between which the rotation axis 36 is sandwiched between the detection position where the photo interrupter 51b detects the protrusion 46a and the detection position where the photo interrupter 51a detects the protrusion 46b is 270 °. , Photo interrupters 51a and 51b and protrusions 46a and 46b are arranged, respectively.

  For example, when a stepping motor is applied as the motor 40, the attitude of the drum 30 is specified based on the detection timing of the protrusion 46a by the photo interrupter 51b and the number of drive pulses for driving the motor 40, and the projection by the projection lens 12 is performed. The angle can be determined.

  The motor 40 is not limited to a stepping motor, and for example, a DC motor can be applied. In this case, for example, as shown in FIG. 2B, a code wheel 44 that rotates together with the gear 43 is provided on the same axis with respect to the gear 43, and photo reflectors 50a and 50b are provided on the support portion 31b. The rotary encoder is configured.

  The code wheel 44 is provided with, for example, a transmission part 45a and a reflection part 45b whose phases are different in the radial direction. By receiving the reflected light of each phase from the code wheel 44 by the photo reflectors 50a and 50b, the rotational speed and the rotational direction of the gear 43 can be detected. Based on the detected rotation speed and rotation direction of the gear 43, the rotation speed and rotation direction of the drum 30 are derived. Based on the derived rotation speed and rotation direction of the drum 30 and the detection result of the protrusion 46b by the photo interrupter 51a, the posture of the drum 30 can be specified and the projection angle by the projection lens 12 can be obtained.

  In the configuration as described above, the initial posture of the drum unit 10 is a posture in which the projection direction by the projection lens 12 is directed in the vertical direction. Therefore, in the initial state, the projection lens 12 is completely hidden by the base 20. FIG. 3A shows the state of the drum unit 10 in the initial posture. In the first embodiment, the protrusion 46a is detected on the photo interrupter 51b in this initial posture, and the rotation control unit 104 described later determines that the drum 30 has reached the starting point of the rotation operation.

  In the following description, unless otherwise specified, “the direction of the drum unit 10” and “the angle of the drum unit 10” are synonymous with “the projection direction by the projection lens 12” and “the projection angle by the projection lens 12”, respectively. And

  When the projector device 1 is activated, the drive unit 32 starts rotating the drum unit 10 so that the projection direction by the projection lens 12 faces the first surface side. Thereafter, the drum unit 10 is rotated to a position where the direction of the drum unit 10, that is, the projection direction by the projection lens 12 becomes horizontal on the first surface side, and the rotation is temporarily stopped. The projection angle of the projection lens 12 when the projection direction by the projection lens 12 is horizontal on the first surface side is defined as a projection angle of 0 °. FIG. 3B shows the posture of the drum unit 10 (projection lens 12) when the projection angle is 0 °. Hereinafter, the posture of the drum unit 10 (projection lens 12) having the projection angle θ is referred to as the θ posture with reference to the posture of the projection angle 0 °.

  For example, assume that image data is input in a 0 ° posture and the light source is turned on. In the drum unit 10, the light emitted from the light source is modulated in accordance with the image data by the display element driven by the drive circuit and is incident on the optical system. The light modulated in accordance with the image data is projected from the projection lens 12 in the horizontal direction, and irradiated onto a projection medium such as a screen or a wall surface.

  The user can rotate the drum unit 10 around the rotation shaft 36 while operating the operation unit 14 or the like while performing projection from the projection lens 12 using image data. For example, the drum unit 10 is rotated in the positive direction from the 0 ° posture to set the rotation angle to 90 ° (90 ° posture), and the light from the projection lens 12 is projected vertically upward with respect to the bottom surface of the base 20. it can. FIG. 3C shows the posture of the drum unit 10 in the posture when the projection angle θ is 90 °, that is, in the 90 ° posture.

  The drum unit 10 can be further rotated in the forward direction from the 90 ° posture. In this case, the projection direction of the projection lens 12 changes from the upward direction perpendicular to the bottom surface of the base 20 to the second surface side. FIG. 3D shows a state where the drum unit 10 is further rotated in the positive direction from the 90 ° posture of FIG. 3C, and is in a posture when the projection angle θ is 180 °, that is, a 180 ° posture. In the projector device 1 according to the first embodiment, the protrusion 46b is detected on the photo interrupter 51a in this 180 ° attitude, and the rotation control unit 104 described later determines that the end point of the rotation operation of the drum 30 has been reached.

  Although details will be described later, the projector device 1 according to the first embodiment rotates the drum unit 10 as shown in, for example, FIGS. 3B to 3D while performing projection, The projection area in the image data can be changed (moved) according to the projection angle by the projection lens 12. As a result, the content of the projected image, the change in the projection position of the projected image on the projection medium, and the content and position of the image area cut out as an image to be projected in the entire image area related to the input image data It is possible to correspond to the change of. Therefore, the user can intuitively grasp which area of all the image areas related to the input image data is projected based on the position of the projected image on the projection medium, and the projected image. It is possible to intuitively perform operations for changing the contents of the.

  Further, the optical system includes an optical zoom mechanism, and the size when the projected image is projected onto the projection medium can be enlarged or reduced by an operation on the operation unit 14. Hereinafter, the enlargement / reduction of the size when the projection image by the optical system is projected onto the projection medium may be simply referred to as “zoom”. For example, when the optical system performs zooming, the projected image is enlarged / reduced around the optical axis of the optical system at the time when the zooming is performed.

  When the user ends the projection of the projection image by the projector device 1 and performs an operation for instructing the operation unit 14 to stop the projector device 1, the projector device 1 is stopped. First, the drum unit 10 returns to the initial posture. The rotation is controlled. When it is detected that the drum unit 10 is directed in the vertical direction and returned to the initial posture, the light source is turned off, and the power is turned off after a predetermined time required for cooling the light source. By turning off the power after the drum unit 10 is directed in the vertical direction, it is possible to prevent the lens surface of the projection lens 12 from becoming dirty when not in use.

<Internal configuration of projector apparatus 1>
Next, a configuration for realizing the operation of the projector device 1 according to the first embodiment as described above will be described. FIG. 4 shows an exemplary configuration of the circuit unit provided in the base 20 and the optical engine unit 110 provided in the drum unit 10 in the projector device 1.

  The optical engine unit 110 includes a light source 111, a display element 114, and a projection lens 12. The light source 111 includes, for example, three LEDs (Light Emitting Diodes) that emit red (R), green (G), and blue (B), respectively. The RGB light beams emitted from the light source 111 are irradiated to the display element 114 through optical systems (not shown).

  In the following description, the display element 114 is a transmissive liquid crystal display element, and has a size of, for example, horizontal 1280 pixels × vertical 800 pixels. Of course, the size of the display element 114 is not limited to this example. The display element 114 is driven by a driving circuit (not shown) and modulates and emits light beams of RGB colors according to image data. The RGB light beams modulated in accordance with the image data emitted from the display element 114 are incident on the projection lens 12 via an optical system (not shown) and projected outside the projector apparatus 1.

  Note that the display element 114 is not limited to a structure using a transmissive liquid crystal display element. For example, the display element 114 may be configured by a reflective liquid crystal display element using LCOS (Liquid Crystal on Silicon) or a DMD (Digital Micromirror Device). In this case, the projector apparatus 1 is configured with an optical system and a drive circuit corresponding to the display element to be applied.

  The projection lens 12 includes a plurality of combined lenses and a lens driving unit that drives the lens in accordance with a control signal. For example, the lens driving unit performs focus control by driving a lens included in the projection lens 12 according to a result of distance measurement based on an output signal from a distance sensor provided in the window unit 13. The lens driving unit drives the lens in accordance with a zoom command supplied from an angle-of-view control unit 106 described later to change the angle of view, thereby controlling the optical zoom.

  As described above, the optical engine unit 110 is provided in the drum unit 10 that can be rotated 360 ° by the rotation mechanism unit 105. The rotation mechanism unit 105 includes the drive unit 32 described with reference to FIG. 2 and the gear 35 that is the configuration on the drum unit 10 side, and rotates the drum unit 10 by using the rotation of the motor 40. That is, the rotation direction of the projection lens 12 is changed by the rotation mechanism unit 105.

  The circuit unit of the projector device 1 includes an image cutout unit 100, a memory 101, an image processing unit 102, an image control unit 103, a rotation control unit 104, an angle of view control unit 106, and a timing generator (TG) 107. CPU120. The timing generator 107 generates a vertical synchronization signal VD, and generates the vertical synchronization signal VD to the image processing unit 102, the image control unit 103, the rotation control unit 104, and a drive circuit (not shown) that drives the display element 114. Supply.

  A CPU (Central Processing Unit) 120 is connected to a ROM (Read Only Memory) and a RAM (Random Access Memory) (not shown), respectively, and uses a RAM as a work memory in accordance with a program stored in the ROM in advance to project a projected image. Various processes of the projector apparatus 1 such as projection, change of the projection angle, and cropping of the image are comprehensively controlled.

  For example, the CPU 120 controls each unit of the projector device 1 according to a program based on a control signal supplied from the operation unit 14 according to a user operation. Thereby, operation | movement of the projector apparatus 1 according to user operation is attained. For example, the CPU 120 controls each unit of the projector device 1 according to a script input from a data input unit (not shown). Thereby, the automatic control of the operation of the projector device 1 can be performed.

  Image data of a still image or a moving image is input to the projector device 1 and supplied to the image cutout unit 100. The image cutout unit 100 stores the supplied image data in the memory 101. The memory 101 stores image data in units of images. That is, corresponding data is stored for each still image when the image data is still image data, and for each frame image constituting the moving image data when the image data is moving image data. The memory 101 corresponds to, for example, a digital high-definition broadcast standard, and can store one or more frame images of 1920 pixels × 1080 pixels. The image cutout unit 100 cuts out (extracts) an image region designated by the image control unit 103 from all regions of the frame image related to the image data stored in the memory 101 and outputs the image region as image data.

  The input image data is preferably shaped into a size corresponding to the image data storage unit in the memory 101 and input to the projector device 1. In this example, the input image data is input to the projector apparatus 1 after the image size is shaped in advance to 1920 pixels × 1080 pixels. However, the present invention is not limited to this, and an image shaping unit that shapes image data input in an arbitrary size into image data having a size of 1920 pixels × 1080 pixels may be provided in the preceding stage of the image clipping unit 100 of the projector device 1.

  The image data output from the image cutout unit 100 is supplied to the image processing unit 102. The image processing unit 102 outputs the image data subjected to the image processing based on the timing indicated by the vertical synchronization signal VD supplied from the timing generator 107.

  The image processing unit 102 performs image processing on the supplied image data using, for example, a memory (not shown). For example, the image processing unit 102 performs size conversion processing on the image data supplied from the image cutout unit 100 so that the size matches the size of the display element 114. The image processing unit 102 can perform various other types of image processing. For example, the size conversion process for the image data can be performed using a general linear conversion process. When the size of the image data supplied from the image cutout unit 100 matches the size of the display element 114, the image data may be output as it is.

  Furthermore, the image processing unit 102 can perform a process related to so-called keystone correction on the projected image.

  Also, interpolation (oversampling) with a constant aspect ratio of the image applies an interpolation filter with a predetermined characteristic to enlarge part or all of the image, and a low-pass filter according to the reduction ratio to eliminate aliasing distortion It is also possible to reduce a part or all of the image by thinning (subsampling) over time or to keep the size as it is without applying a filter.

  In addition, when an image is projected in an oblique direction, an operator such as Laplacian (or a one-dimensional filter is applied in the horizontal and vertical directions to prevent the image from being out of focus and blurring in the periphery. The edge of the above-described blurred image portion in the peripheral portion can be emphasized by performing the edge enhancement processing according to (1).

  Furthermore, in order to prevent the brightness of the entire screen from changing due to the projection size (area) being changed by the keystone correction or the like, adaptive brightness is maintained so that the brightness remains uniform. Adjustments can also be made. Then, when the peripheral portion of the projected image texture includes an oblique line, the image processing unit 102 mixes a local halftone so as not to make the edge jagged, or applies a local low-pass filter. It is possible to prevent the diagonal lines from being observed as jagged lines by blurring the edge jags.

  The image data output from the image processing unit 102 is supplied to the display element 114. In practice, this image data is supplied to a drive circuit that drives the display element 114. The drive circuit drives the display element 114 based on the supplied image data and the vertical synchronization signal VD. For example, the drive circuit updates the display by the display element 114 according to the timing of the vertical synchronization signal VD supplied from the timing generator 107.

  The rotation control unit 104 generates a drive pulse having a predetermined pulse width for driving the motor 40 that is a stepping motor, for example, according to a command from the CPU 120 according to a user operation on the operation unit 14 and supplies the drive pulse to the rotation mechanism unit 105. To do. The rotation control unit 104 generates a driving pulse in synchronization with the vertical synchronization signal VD supplied from the timing generator 107.

  The rotation mechanism unit 105 includes the above-described drive unit 32 and photo interrupters 51a and 51b. In the rotation mechanism unit 105, the drive unit 32 drives the motor 40 according to the drive pulse supplied from the rotation control unit 104 to control the rotation operation of the drum unit 10 (drum 30).

  On the other hand, the output of the photo interrupters 51 a and 51 b described above is supplied from the rotation mechanism unit 105 to the rotation control unit 104. The rotation control unit 104 has a counter, for example, and counts the number of drive pulses. The rotation control unit 104 acquires the detection timing of the protrusion 46a based on the output of the photo interrupter 51b, and resets the number of pulses counted by the counter at the detection timing of the protrusion 46a. The rotation control unit 104 can sequentially obtain the angle of the drum unit 10 (drum 30) based on the number of pulses counted by the counter, and can acquire the attitude (angle) of the drum unit 10. Information indicating the angle of the drum unit 10 is supplied to the image control unit 103. In this way, when the projection direction of the projection lens 12 is changed, the rotation control unit 104 can derive an angle between the projection direction before the change and the projection direction after the change.

  The angle-of-view control unit 106 issues a zoom instruction, that is, an angle-of-view change instruction to the projection lens 12 in accordance with, for example, a command from the CPU 120 according to a user operation on the operation unit 14. The lens driving unit of the projection lens 12 drives the lens according to the zoom instruction to perform zoom control. The angle-of-view control unit 106 supplies information related to the angle of view derived from the zoom instruction and the zoom magnification associated with the zoom instruction to the image control unit 103.

  The image control unit 103 specifies an image cut-out region by the image cut-out unit 100 based on the information related to the angle supplied from the rotation control unit 104 and the information related to the angle of view supplied from the view angle control unit 106. At this time, the image control unit 103 designates a cutout region in the image data based on a line position corresponding to an angle between projection directions before and after the change of the projection lens 12. The image control unit 103 designates an image cutout area to the image cutout unit 100. Further, the image control unit 103 instructs the image cutout unit 100 to read image data from the designated image cutout region in synchronization with the vertical synchronization signal VD supplied from the timing generator 107.

  In the above description, the image cutout unit 100, the image processing unit 102, the image control unit 103, the rotation control unit 104, and the angle of view control unit 106 have been described as if they were separate hardware. It is not limited to. For example, each of these units may be realized by a program module operating on the CPU 120.

<Cut out image data>
Next, a process for cutting out image data stored in the memory 101 by the image control unit 103 and the image cutout unit 100 according to the first embodiment will be described. FIG. 5 is a conceptual diagram for explaining a process for extracting image data stored in the memory 101. With reference to FIG. 5A, an example in which the image data 141 in the specified cutout area is cut out from the image data 140 stored in the memory 101 will be described.

  In the memory 101, for example, addresses are set in units of lines in the vertical direction and in units of pixels in the horizontal direction. The addresses of the lines increase from the lower end to the upper end of the image (screen), and the addresses of the pixels are from the left end of the image. It shall increase toward the right end.

The image control unit 103 addresses the line q ₀ and the line q ₁ in the vertical direction as the cut-out region of the image data 140 of Q lines × P pixels stored in the memory 101 with respect to the image cut-out unit 100, and Address pixels p ₀ and p ₁ in the direction. The image cutout unit 100 reads out each line within the range of the lines q _{0 to} q ₁ from the memory 101 in accordance with this address specification over the pixels p _{0 to} p ₁ . At this time, for example, each line is read from the upper end to the lower end of the image, and each pixel is read from the left end to the right end of the image. Details of access control to the memory 101 will be described later.

The image clipping unit 100, read from the memory 101, and supplies the line q ₀ to q _1, and the image data 141 in the range of the pixel p ₀ ~p ₁ to the image processing unit 102. The image processing unit 102 performs a size conversion process that matches the size of the image based on the supplied image data 141 with the size of the display element 114. As an example, when the size of the display element 114 is R lines × S pixels, the maximum magnification m that satisfies both the following expressions (1) and (2) is obtained. Then, the image processing unit 102 enlarges the image data 141 by this magnification m, and obtains image data 141 ′ whose size has been converted as illustrated in FIG. 5B.
m × (p ₁ −p ₀ ) ≦ S (1)
m × (q ₁ −q ₀ ) ≦ R (2)

Next, the designation (update) of the cutout area according to the projection angle according to the first embodiment will be described. FIG. 6 shows an example of clip region designation when the drum unit 10 is in the 0 ° posture, that is, the projection angle is 0 °. In the projector device (PJ) 1, by the projection lens 12, Te than at angle alpha, relative to the projection surface 130 is a projection medium, such as a screen, the projection position in the case of projecting the image 131 ₀ a projection angle of 0 ° Is a position Pos ₀ corresponding to the light beam center of the light projected from the projection lens 12. In addition, when the projection angle is 0 °, the image data stored in the memory 101 is an image based on the image data from the line S at the lower end of the region designated in advance to perform projection with the posture of the projection angle 0 ° to the line L. Shall be projected. The region from the line S to the line L includes the number of lines ln.

  The number of lines ln is the number of lines in the maximum effective area of the display element 114. Further, the angle of view α is projected when an image is projected when the effective area in the vertical direction in which display is enabled on the display element 114 takes a maximum value, that is, when an image having the number of lines ln is projected. The angle at which the image is viewed from the projection lens 12 in the vertical direction.

  The angle of view α and the effective area of the display element 114 will be described using a more specific example. It is assumed that the display element 114 has a vertical size of 800 lines. For example, when the projection image data has a vertical size of 800 lines and the projection image data is projected using all the lines of the display element 114, the vertical effective area of the display element 114 has a maximum value of 800 lines. (= Number of lines ln). In this case, the angle of view α is an angle at which 1 to 800 lines of the projection image are expected from the projection lens 12.

  Further, the projection image data may have a vertical size of 600 lines, and the projection image data may be projected using only 600 lines of 800 lines (= number of lines ln) of the display element 114. At this time, the effective area in the vertical direction of the display element 114 is 600 lines. In this case, only the portion of the effective area by the projection image data with respect to the maximum value of the effective area of the angle of view α is projected.

The image control unit 103 instructs the image cutout unit 100 to cut out and read lines S to L of the image data 140 stored in the memory 101. Here, in the horizontal direction, all of the image data 140 from the left end to the right end is read. In accordance with an instruction from the image control unit 103, the image cutout unit 100 sets the areas S to L of the image data 140 as cutout regions, reads the image data 141 of the set cutout regions, and supplies the image data to the image processing unit 102. . In the example of FIG. 6, the image 131 ₀ based on the image data 141 ₀ having the number of lines ln from the line S to the line L of the image data 140 is projected onto the projection position Pos ₀ on the projection surface 130. In this case, the image based on the image data 142 in the area from the line L to the uppermost line in the entire area of the image data 140 is not projected.

  Next, for example, the case where the drum unit 10 is rotated by a user operation on the operation unit 14 and the projection angle of the projection lens 12 becomes the angle θ will be described. In the first embodiment, the image control unit 103 designates a cutout region corresponding to the projection angle θ with respect to the image data 140 on the memory 101 at a timing synchronized with the vertical synchronization signal VD.

The setting of the cut-out area with respect to the projection angle θ will be described more specifically with reference to FIG. For example, consider a case in which the projection position of the drum unit 10 is rotated in the positive direction from the 0 ° posture and the projection angle of the projection lens 12 becomes an angle θ (> 0 °). In this case, the projection position with respect to the projection surface 130 moves to the upper projection position Pos ₁ with respect to the projection position Pos ₀ with a projection angle of 0 °. At this time, the image control unit 103 designates a cutout region for the image data 140 stored in the memory 101 to the image cutout unit 100 according to the following expressions (3) and (4). Expression (3) indicates the line R _S at the lower end of the cutout area, and Expression (4) indicates the line R _L at the upper end of the cutout area.
R _S = θ × (ln / α) + S (3)
R _L = θ × (ln / α) + S + ln (4)

  In the expressions (3) and (4), the value ln and the value α indicate the number of lines ln and the angle of view α, respectively. Further, the value S indicates a line at the lower end of the cutout region in the 0 ° posture described with reference to FIG.

  In Expressions (3) and (4), (ln / α) is approximately averaged when the angle of view α projects the number of lines ln (the number of lines per unit angle of view (which varies depending on the shape of the projection surface). Including the concept of number of lines). Therefore, θ × (ln / α) represents the number of lines corresponding to the projection angle θ by the projection lens 12 in the projector device 1. This means that when the projection angle changes by the angle Δθ, the position of the projection image moves by a distance corresponding to the number of lines {Δθ × (ln / α)} in the projection image. Therefore, Expression (3) and Expression (4) respectively indicate the lower end and upper end line positions in the image data 140 of the projection image when the projection angle is the angle θ. This corresponds to the read address for the image data 140 on the memory 101 at the projection angle θ.

As described above, in the first embodiment, an address for reading the image data 140 from the memory 101 is designated according to the projection angle θ. Thus, in the example of FIG. 7, for example, from the memory 101, the image data 140, image data 141 ₁ position corresponding to the projection angle θ is read out, the image 131 ₁ of the image data 141 ₁ read , And is projected onto the projection position Pos ₁ corresponding to the projection angle θ of the projection surface 130.

  Thereby, according to 1st Embodiment, when projecting the image data 140 of a size larger than the size of the display element 114, the correspondence relationship between the position in the projected image and the position in the image data is Kept. Further, since the projection angle θ is obtained based on the drive pulse of the motor 40 for driving the drum 30 to rotate, the projection angle θ can be obtained with substantially no delay with respect to the rotation of the drum unit 10. It is possible to obtain the projection angle θ without being affected by the projected image and the surrounding environment.

  Next, the setting of the cut-out area when the optical zoom by the projection lens 12 is performed will be described. As already described, in the case of the projector device 1, optical zooming is performed by driving the lens driving unit and increasing or decreasing the angle of view α of the projection lens 12. An increase in the angle of view due to the optical zoom is defined as an angle Δ, and an angle of view of the projection lens 12 after the optical zoom is defined as an angle of view (α + Δ).

  In this case, even if the angle of view increases due to the optical zoom, the cutout area for the memory 101 does not change. In other words, the number of lines included in the projected image with the angle of view α before the optical zoom and the number of lines included in the projected image with the angle of view (α + Δ) after the optical zoom are the same. Therefore, after the optical zoom, the number of lines included per unit angle changes before the optical zoom.

The designation of the cut-out area when optical zoom is performed will be described more specifically with reference to FIG. In the example of FIG. 8, optical zoom is performed to increase the angle of view Δ by the angle of view α in the state of the projection angle θ. By performing the optical zoom, the projection image projected on the projection surface 130 is optical as shown as an image 131 ₂ with the light beam center (projection position Pos ₂ ) of the light projected onto the projection lens 12 in common, for example. The angle of view is enlarged by Δ for the case where zooming is not performed.

When the optical zoom for the angle of view Δ is performed, assuming that the number of lines designated as a cutout region for the image data 140 is ln lines, the number of lines included per unit angle is {ln / (α + Δ)}. expressed. Therefore, the cutout region for the image data 140 is specified by the following expressions (5) and (6). In addition, the meaning of each variable in Formula (5) and Formula (6) is the same as the above-mentioned Formula (3) and Formula (4).
R _S = θ × {ln / (α + Δ)} + S (5)
R _L = θ × {ln / (α + Δ)} + S + ln (6)

From the image data 140, the equation (5) and the image data 141 ₂ regions represented by the formula (6) is read, an image 131 ₂ of the image data 141 ₂ read, by the projection lens 12, projection The projection is performed on the projection position Pos _{2 of the} surface 130.

  As described above, when the optical zoom is performed, the number of lines included per unit angle changes compared to the case where the optical zoom is not performed, and the amount of change in the line with respect to the change in the projection angle θ performs the optical zoom. It will be different compared to the case without it. This is a state where the gain corresponding to the angle of view Δ increased by the optical zoom is changed in the designation of the read address corresponding to the projection angle θ with respect to the memory 101.

In the first embodiment, the address for reading the image data 140 from the memory 101 is specified according to the projection angle θ and the angle of view α of the projection lens 12. Accordingly, even when subjected to optical zoom, the address of the image data 141 ₂ to be projected, can be appropriately specified for the memory 101. Accordingly, even when optical zoom is performed, when image data 140 having a size larger than the size of the display element 114 is projected, the correspondence between the position in the projected image and the position in the image data Is preserved.

Next, the case where an offset is given to the projection position of an image will be described with reference to FIG. When the projector apparatus 1 is used, the 0 ° attitude (projection angle 0 °) is not necessarily the lowest end of the projection position. For example, as illustrated in FIG. 9, a case where the projection position Pos ₃ with a predetermined projection angle θ _ofst is set to the lowest projection position may be considered. In this case, the image 131 ₃ by the image data 141 _3, as compared with the case where no offset is given, will be projected at a position shifted upward by a height corresponding to the projection angle theta _ofst. The projection angle θ at the time of projecting an image having the lowermost line of the image data 140 as the lowermost end is set as an offset angle θ _ofst due to offset.

In this case, for example, it can be considered that the offset angle θ _ofst is regarded as a projection angle of 0 °, and a cutout region for the memory 101 is designated. When applied to the above formulas (3) and (4), the following formulas (7) and (8) are obtained. In addition, the meaning of each variable in Formula (7) and Formula (8) is the same as the above-mentioned Formula (3) and Formula (4).
R _S = (θ−θ _ofst ) × (ln / α) + S (7)
R _L = (θ−θ _ofst ) × (ln / α) + S + ln (8)

  By the way, the method for specifying the cut-out area according to the above-described formulas (3) and (4) assumes that the projection surface 130 on which the projection lens 12 projects is a cylinder centered on the rotation axis 36 of the drum unit 10. Based on a cylindrical model. However, in practice, it is considered that the projection surface 130 is often a vertical surface (hereinafter simply referred to as “vertical surface”) that forms an angle of 90 ° with respect to the projection angle θ = 0 °. When image data having the same number of lines is cut out from the image data 140 and projected onto a vertical plane, the image projected on the vertical plane extends in the vertical direction as the projection angle θ increases. Therefore, after the image cutout unit 100, the image processing unit 102 performs the following image processing.

  An image projected on a vertical plane will be described with reference to FIGS. 10 and 11. In FIG. 10, consider a case where an image is projected from the projection lens 12 onto a projection surface W that is separated from the position B by a distance r with the position B as the position of the rotation shaft 36 of the drum unit 10.

In the above-described cylindrical model, a projection image is projected with an arc C having a radius r centered on the position B as a projection plane. Each point of the arc C is equidistant from the position B, and the light flux center of the light projected from the projection lens 12 is a radius of a circle including the arc C. Therefore, even if the projection angle θ is increased from θ ₀ of 0 ° to θ ₁ , θ ₂ ,..., The projected image is always projected on the projection surface with the same size.

On the other hand, when an image is projected from the projection lens 12 onto the projection surface W that is a vertical surface, when the projection angle θ is increased from θ ₀ to θ ₁ , θ ₂ ,. The position at which the center of the light beam is irradiated onto the projection surface W varies according to the function of the angle θ according to the characteristic of the tangent function. Therefore, the projected image extends upward in accordance with the ratio M shown in the following equation (9) as the projection angle θ increases.
M = (180 × tan θ) / (θ × π) (9)

  According to Expression (9), for example, when the projection angle θ = 45 °, the projection image is stretched at a ratio of about 1.27 times. In addition, when the projection surface W is higher than the length of the radius r and projection at the projection angle θ = 60 ° is possible, the projection is performed at a ratio of about 1.65 times at the projection angle θ = 60 °. The image will stretch.

  In addition, the line interval in the projected image on the projection surface W also increases as the projection angle θ increases, as illustrated in FIG. In this case, according to the position on the projection surface W in one projection image, the line interval is widened according to the above equation (9).

  Therefore, the projector device 1 performs a reduction process on the image data of the image to be projected at a ratio of the reciprocal of the above-described equation (9) according to the projection angle θ of the projection lens 12. The reduction processing is preferably larger than the image data cut out based on the cylindrical model. That is, depending on the height of the projection plane W, which is a vertical plane, when the projection angle θ = 45 °, the projection image is stretched at a ratio of about 1.27 times, so that it is reduced to about 78% of the reciprocal thereof. It will be. Therefore, in order to use up the image memory to the full, cut out a large number of lines of about 22% or more in advance and read an area larger than the area of the image data corresponding to the projected image as an image of the cut-out area. Input to the image processing unit 102 is desirable.

  As an example, when the image control unit 103 stores the image data input to the projector device 1 in the memory 101 by the image cutout unit 100, the image control unit 103 sets the reciprocal ratio of the above equation (9) to the image data. Using the image data, a reduction process is performed on the image data in advance for each line of the image when the image data is projected. In the reduction process, a line is thinned by applying a low-pass filter of several taps to the line (vertical pixel) at a reduction rate depending on the projection angle θ. To be precise, the limit value of the band of the low-pass filter needs to be changed depending on the projection angle θ. At this time, the filter characteristics are uniformly determined at a reduction ratio corresponding to the maximum projection angle θ, the filter characteristics are determined uniformly at a reduction ratio corresponding to approximately ½ of the maximum projection angle θ, etc. General linear interpolation can be used. Further, after the filtering process, it is necessary to perform sub-sampling on the thinned line depending on the projection angle θ in the screen. In this case as well, processing such as uniform thinning at a reduction rate corresponding to the maximum projection angle θ, uniform thinning at a reduction rate corresponding to approximately ½ of the maximum projection angle θ is performed. You can also. When the low-pass filter process and the thinning-out process are performed more accurately, it is possible to obtain better characteristics by dividing into several areas and performing the process uniformly for each area.

  Note that the image processing using the formula (9) is not limited to an example performed when image data is stored in the memory 101. This image processing may be performed by the image processing unit 102, for example.

  Further, in an environment where the projector apparatus 1 is actually used, the height of the projection surface W is limited, and it is considered that the surface R is often formed by folding back 90 ° at a certain position A. This surface R can also be used as the projection surface of the projector device 1. In this case, the image projected onto the projection surface R is further increased as the projection angle θ is increased as described above as the projection position goes beyond the position A and goes directly upward (projection angle θ = 90 °). The image is shrunk with characteristics opposite to those of the image projected on the projection surface W.

  Therefore, when an image based on image data is projected at the projection angles of 0 ° and 90 °, the reduction process using Expression (9) is not performed on the projected image data. In addition, when the length (height) of the projection surface W and the length of the projection surface R are substantially equal, the reduction process using the formula (9) for the image data to be projected is performed from the projection angle 0 ° to the projection surface. The reduction process to the uppermost position A of W and the reduction process from the position A to the projection angle of 90 ° are executed as symmetrical processes. Thereby, it is possible to reduce the load on the reduction processing in the image control unit 103.

  In the above-described example, the description has been made on the assumption that a vertical surface forms an angle of 90 ° with respect to the projection angle θ = 0 °. Depending on the rotation angle of the drum unit 10, it may be possible to project onto a plane that forms an angle of 180 ° with respect to the projection angle θ = 0 °. When image data having the same number of lines is cut out from the image data 140 and projected onto this surface, the projected image shrinks in the vertical direction as the projection angle θ increases. Therefore, after the image cutout unit 100, the image processing unit 102 performs image processing opposite to the above description.

That is, when the projection angle θ is increased from θ ₀ to θ ₁ , θ ₂ ,..., The distance from the projection lens 12 to the projection surface changes. Therefore, the projector device 1 performs an enlargement process on the image data of the image to be projected, in accordance with the projection angle θ of the projection lens 12, contrary to the above description.

  As described above, when the distance from the projection unit 12 to the projection surface decreases as the projection direction changes from the first projection direction to the second projection direction, the image cutout unit of the image projection apparatus 1 You may make it perform the expansion process based on projection angle (theta) for every pixel of cutout image data.

  In the following description, unless otherwise specified, the description of angles is based on a cylindrical model, and correction based on Expression (9) is appropriately performed as necessary, such as in the case of projection on a vertical plane.

<About memory control>
Next, access control of the memory 101 will be described with reference to FIGS. For each vertical sync signal VD, the image data is transmitted in the horizontal direction on the screen for each line from the left end to the right end of the image, and each line is sequentially transmitted from the upper end to the lower end of the image. The In the following description, the case where the image data has a size of horizontal 1920 pixels × vertical 1080 pixels (lines) corresponding to the digital high vision standard will be described as an example.

Hereinafter, an example of access control in the case where the memory 101 includes four memory areas 101Y ₁ , 101Y ₂ , 101T _1, and 101T ₂ that can be independently controlled for access will be described. That is, as shown in FIG. 12, the memory 101 has a size of horizontal 1920 pixels × vertical 1080 pixels (lines), and memory areas 101Y ₁ and 101Y ₂ used for writing / reading image data, and horizontal 1080 pixels, respectively. A memory area 101T ₁ and 101T ₂ used for writing / reading image data with the size of the vertical pixel 1920 (line) are provided. Hereinafter, each of the memory areas 101Y ₁ , 101Y ₂ , 101T ₁ and 101T ₂ will be described as a memory area Y ₁ , a memory area Y ₂ , a memory area T ₁ and a memory area T ₂ , respectively.

FIG. 13 is an example of a time chart for explaining access control to the memory 101 by the image cutout unit 100. 13A shows the projection angle θ of the projection lens 12, and FIG. 13B shows the vertical synchronization signal VD. 13C shows the input timing of the image data D ₁ , D ₂ ,... Input to the image cutout unit 100, and FIGS. 13D to 13G show the memory areas Y ₁ , T, respectively. An example of access from the image cutout unit 100 to ₁ , Y _2, and T ₂ is shown. In FIG. 13 (d) to FIG. 13 (g), blocks marked with “R” indicate reading, and blocks marked with “W” indicate writing.

Image data D ₁ , D ₂ , D ₃ , D ₄ , D ₅ , D ₆ ,... Each having an image size of 1920 pixels × 1080 lines is input to the image cutout unit 100 for each vertical synchronization signal VD. The The image data D ₁ , D ₂ ,... Are input after the vertical synchronization signal VD in synchronization with the vertical synchronization signal VD. In addition, the projection angles of the projection lens 12 corresponding to the vertical synchronizing signals VD are set as projection angles θ ₁ , θ ₂ , θ ₃ , θ ₄ , θ ₅ , θ ₆ ,. Thus, the projection angle θ is acquired for each vertical synchronization signal VD.

First, image data D ₁ is input to the image cutout unit 100. As described above, the projector device 1 according to the first embodiment moves the projection position of the projection image by changing the projection angle θ by the projection lens 12 by rotating the drum unit 10 and responds to the projection angle θ. To specify the readout position for image data. Therefore, it is convenient that the image data is longer in the vertical direction. In general, image data often has a horizontal size larger than a vertical size. Therefore, for example, it is conceivable that the user rotates the camera 90 ° to take an image, and the image data obtained by this imaging is input to the projector device 1.

That is, the image by the image data D ₁ , D ₂ ,... Input to the image cutout unit 100 is an image of the correct orientation as judged from the image content, like an image 160 shown as an image in FIG. The image is a landscape image rotated 90 ° from the side.

The image clipping unit 100, the image data D ₁ inputted, first, the memory area Y _1, written in the timing WD ₁ corresponding to the input timing of the image data D ₁ (timing WD ₁ shown in FIG. 13 (d) ). The image clipping unit 100, the image data D _1, as shown on the left side in FIG. 14 (b), is written to the memory area Y ₁ in the order of lines in a horizontal direction. On the right side of FIG. 14B, an image 161 based on the image data D ₁ written in the memory area Y ₁ is shown as an image. The image data D ₁ is written in the memory area Y ₁ as the image 161 having the same image as the input image 160.

As shown in FIG. 14C, the image cutout unit 100 converts the image data D ₁ written in the memory area Y ₁ into the vertical synchronization signal VD next to the vertical synchronization signal VD into which the image data D ₁ is written. in simultaneously with the start timing RD _1, read from the memory area Y ₁ (FIG. 13 timing RD ₁ of (d)).

At this time, the image clipping unit 100, the image data D _1, as the start pixel readout in the lower left corner of the pixels of the image, will read for each pixel across lines sequentially in the vertical direction. When the pixel at the upper end of the image is read out, each pixel is read out in the vertical direction with the next pixel to the right of the pixel at the reading start position in the vertical direction as the read start pixel. This operation is repeated until the readout of the pixel at the upper right corner of the image is completed.

In other words, the image cutout unit 100 sets the line direction as the vertical direction from the lower end to the upper end of the image, and reads the image data D ₁ from the memory area Y _{1 for} each line in the vertical direction. Sequentially read from pixel to right end.

The image cutout unit 100 directs the pixels of the image data D ₁ read from the memory area Y ₁ in this way toward the line direction with respect to the memory area T ₁ as shown on the left side of FIG. Then, writing is sequentially performed for each pixel (timing WD _{1 in} FIG. 13E). That is, every time, for example, one pixel is read from the memory area Y ₁ , the image cutout unit 100 writes the read one pixel in the memory area T ₁ .

The right side of FIG. 15A shows the image 162 of the image data D ₁ written in the memory area T ₁ in this way. The image data D ₁ is written in the memory area T ₁ as a size of horizontal 1080 pixels × vertical 1920 pixels (line), and the image 160 at the time of input is rotated 90 ° clockwise to switch the horizontal direction and the vertical direction. Image 162.

The image clipping unit 100 performs addressing of the clip region that is specified in the image control unit 103 to the memory area T _1, reads the image data of the specified region as the cut-out area from the memory area T _1. The timing of this reading is delayed by the amount of 2 vertical synchronization signals VD with respect to the timing at which the image data D ₁ is input to the image cutout unit 100, as shown as timing RD ₁ in FIG. become.

As described above, the projector device 1 according to the first embodiment moves the projection position of the projection image by changing the projection angle θ by the projection lens 12 by rotating the drum unit 10 and responds to the projection angle θ. To specify the readout position for image data. For example, the image data D ₁ is input to the image cutout unit 100 at the timing of the projection angle θ ₁ . Projection angle theta in the timing for projecting an image of the image data D ₁ actually is, from the projection angle theta _1, it is likely that changes in the incident angle theta ₁ is different from the projection angle theta _3.

Therefore, cut-out area for reading image data D ₁ from the memory area T ₁ is expected to change in the projection angle theta, to read out at a range greater than the area of the image data corresponding to an image to be projected .

This will be described more specifically with reference to FIG. The left side of FIG. 15B shows an image of the image 163 based on the image data D ₁ stored in the memory area T ₁ . In this image 163, it is assumed that the area actually projected is a projection area 163a, and the other area 163b is a non-projection area. In this case, the image control unit 103 has a projection angle θ by the projection lens 12 with respect to the memory area T ₁ at least during the period of the two vertical synchronization signals VD as compared with the image data area corresponding to the image in the projection area 163a. A cutout area 170 that is as large as the number of lines corresponding to the change when the change is maximum is designated.

The image clipping unit 100, the image data D ₁ at the timing of the next vertical synchronizing signal VD of the written vertical synchronizing signal VD to the memory area T _1, reads the image data from the cutout region 170. Thus, the image data to be projected is read from the memory area T ₁ at the timing of the projection angle θ ₃ , supplied to the display element 114 through the image processing unit 102 at the subsequent stage, and projected from the projection lens 12.

Image data D ₂ is input to the image cutout unit 100 at the timing of the vertical synchronization signal VD next to the vertical synchronization signal VD to which the image data D ₁ is input. In this timing, the memory area Y ₁ is image data D1 is written. Therefore, the image clipping unit 100 writes the image data D ₂ in the memory area Y ₂ (timing WD ₂ of FIG. 13 (f)). At this time, the order of writing the image data D _{2 to} the memory area Y ₂ is the same as the order of writing the image data D _{1 to} the memory area Y ₁ , and the image is also the same (FIG. 14B). reference).

That is, the image clipping unit 100, the image data D _2, as the starting pixel readout in the lower left corner of the pixel of the image, across lines sequentially in the vertical direction read-out to the top of the pixels of the image for each pixel, then the vertical Each pixel is read out in the vertical direction with the pixel on the right side of the pixel at the readout start position as the readout start pixel (timing RD _{2 in} FIG. 13F). This operation is repeated until the readout of the pixel at the upper right corner of the image is completed. The image cutout unit 100 sequentially writes the pixels of the image data D ₂ read out from the memory area Y ₂ in this way into the memory area T ₂ for each pixel in the line direction (FIG. 13 (g)). timing WD ₂₎ go (FIG. 15 (a) see left).

The image clipping unit 100 performs the addressing of the specified cutout region to the image controller 103 to the memory area T _2, the image data of the specified region as the cutout region, the timing RD of FIG. 13 (g) ₂ read from the memory area T _2. At this time, as described above, the image control unit 103, the memory area T _2, anticipation of change in the projection angle theta, region cut out area larger than the area of the image data corresponding to an image to be projected Specify as 170.

The image clipping unit 100, the image data D ₂ at the timing of the next vertical synchronizing signal VD of the written vertical synchronizing signal VD to the memory area T _2, to read the image data from the cutout region 170. Thus, the image data of the cutout area 170 in the image data D ₂ input to the image cutout unit 100 at the timing of the projection angle θ ₂ is read from the memory area T ₂ at the timing of the projection angle θ ₄ , and subsequent image processing is performed. The light is supplied to the display element 114 via the unit 102 and projected from the projection lens 12.

Thereafter, in the same manner, the image data D ₃ , D ₄ , D ₅ ,... Are sequentially processed by alternately using the set of memory areas Y ₁ and T _{1 and} the set of memory areas Y ₂ and T _2. I will do it.

As described above, in the first embodiment, the memory areas Y ₁ and Y ₂ used for writing and reading image data with a size of horizontal 1920 pixels × vertical 1080 pixels (lines) with respect to the memory 101; Memory areas T ₁ and T ₂ used for writing and reading image data are provided in a size of horizontal 1080 pixels × vertical 1920 (pixel lines). This is because a dynamic random access memory (DRAM) used for an image memory generally has a slower access speed in the vertical direction than in the horizontal direction. In the case of using another easily accessible memory that can obtain the same access speed in the horizontal direction and the vertical direction, a configuration in which two memories having a capacity corresponding to image data may be used.

<Flow of processing for projecting image data>
Next, the flow of processing when projecting an image based on image data in the projector apparatus 1 will be described using the flowchart of FIG.

In step S100, along with the input of the image data, various setting values relating to the projection of the image based on the image data are input to the projector apparatus 1. For example, the CPU 120 acquires the various set values that have been input. The various setting values acquired here include, for example, a value indicating whether or not to rotate the image based on the image data, that is, whether or not the horizontal direction and the vertical direction of the image are switched, the image enlargement ratio, and the projection Including the offset angle θ _ofst . Various setting values may be input to the projector apparatus 1 as data in accordance with the input of image data to the projector apparatus 1 or may be input by operating the operation unit 14.

  In the next step S <b> 101, image data for one frame is input to the projector device 1, and the input image data is acquired by the image cutout unit 100. The acquired image data is written into the memory 101.

In the next step S102, the image control unit 103 acquires the offset angle θ _ofst . In the next step S103, the image control unit 103 acquires the cutout size, that is, the size of the cutout area in the input image data. The image control unit 103 may acquire the size of the cutout area from the setting value acquired in step S <b> 100 or according to an operation on the operation unit 14. In the next step S <b> 104, the image control unit 103 acquires the angle of view α of the projection lens 12. The image control unit 103 acquires the angle of view α of the projection lens 12 from, for example, the angle of view control unit 106. Further, in the next step S <b> 105, the image control unit 103 acquires the projection angle θ of the projection lens 12 from, for example, the rotation control unit 104.

In the next step S106, the image control unit 103 performs the above-described expression (3) based on the offset angle θ _ofst acquired in steps S102 to S105, the size of the cutout region, the angle of view α, and the projection angle θ. ) To (8) are used to obtain a cutout region for the input image data. The image control unit 103 instructs the image cutout unit 100 to read out image data from the obtained cutout region. In accordance with an instruction from the image control unit 103, the image cutout unit 100 reads out the image data in the cutout region from the image data stored in the memory 101, and cuts out the image data. The image clipping unit 100 supplies the image data of the clipping region read from the memory 101 to the image processing unit 102.

  In step S107, the image processing unit 102 performs size conversion processing on the image data supplied from the image cutout unit 100, for example, according to the above-described formulas (1) and (2). The image data subjected to the size conversion process by the image processing unit 102 is supplied to the display element 114. The display element 114 modulates the light from the light source 111 according to the image data and emits it. The emitted light is projected from the projection lens 12.

  In the next step S108, the CPU 120 determines whether or not there is an input of image data of the next frame of the image data input in step S101 described above. If it is determined that there is an input of image data of the next frame, the CPU 120 returns the process to step S101, and performs the processes of steps S101 to S107 described above on the image data of the next frame. . That is, the processing in steps S101 to S107 is repeated for each frame of image data, for example, according to the vertical synchronization signal VD of the image data. Therefore, the projector device 1 can follow each process for each frame with respect to the change in the projection angle θ.

  On the other hand, if it is determined in step S108 that the image data of the next frame is not input, the CPU 120 stops the image projection operation in the projector device 1. For example, the CPU 120 controls to turn off the light source 111 and issues a command to the rotation mechanism unit 105 to return the posture of the drum unit 10 to the initial posture. Then, after the posture of the drum unit 10 returns to the initial posture, the CPU 120 stops the fan that cools the light source 111 and the like.

  As described above, according to the projector device 1, it is possible to perform image projection that allows the user to easily grasp the position of the projected subject image in the image related to the input image data while maintaining the resolution of the image data. it can.

<High-quality projection image (1)>
Next, a first method for improving the quality of the projection image according to the first embodiment will be described. According to the control of the projector device 1 described above, the cutout region for cutting out the projection image data for projection from the image data stored in the memory 101 is changed according to the projection angle θ. Therefore, as illustrated in FIG. 17A to FIG. 17C, the projection image projected on the projection medium is moved in the input image data 200 according to the projection angle θ, and the input image data 200. Can be projected.

  That is, as shown in FIG. 17A, for example, in a state where the projection angle is 0 °, a cutout area 201a including the lower end of the input image data 200 is specified for the memory 101, and an image in the cutout area 201a is specified. Data is read and projected as projection image data. When the projection angle θ is increased, as shown in FIG. 17B, the cutout area 201b moved by the height y corresponding to the increase in the projection angle θ with respect to the cutout area 201a is moved to the memory 101. The image data in the cutout area 201b is read out as projection image data. Similarly, when the projection angle θ is further increased, as shown in FIG. 17C, the height y corresponding to the increase in the projection angle θ with respect to the cut-out region 201b with respect to the memory 101 is similarly displayed. Projection image data is read out from the cutout area 201c specified by movement and projected.

  By the way, as described above, the reading of the image data related to the cutout area designated on the memory 101 is performed in synchronization with the vertical synchronization signal VD, and the display on the display element 114 is performed at every timing of the vertical synchronization signal VD. Updated. Here, the case where the projection angle θ changes at a certain high speed will be described with reference to FIG.

Initially, for example, in a state where the projection angle is 0 °, as shown in FIG. 18A, the image data in the cutout area 201a designated for the memory 101 is read as projection image data based on the vertical synchronization signal VD. It is assumed that it has been projected. When the projection angle θ is changed from this state, the projection position on the projection medium moves by a height z ₁ corresponding to the change Δθ ₁ of the projection angle θ after t ₁ hours. This is shown in FIG.

In the state of FIG. 18B, when t ₁ time is shorter than the frame period, the cutout area 201a for the memory 101 is not changed and the display element 114 is not updated, and only the projection direction by the projection lens 12 is used. Changes. Therefore, the projection image is obtained by moving the projection image data read from the cutout area 201a at the time of the projection angle 0 ° by the height z ₁ corresponding to the change Δθ ₁ of the projection angle θ. For example, when the cut-out area 201a specified at the time of the projection angle 0 ° includes the lower end portion of the input image data 200, the projection image including the lower end portion is projected as it is lifted by the height z ₁ of the projection angle θ. Will be.

Next, it is assumed that the projection angle θ is continuously changed for t ₂ hours from the state of FIG. 18B, and one frame period has elapsed from the state of FIG. At this time, the projection position by the projection lens 12 is further moved from the position of FIG. 18B by the height z ₂ according to the change Δθ ₂ of the projection angle θ. In this case, as shown in FIG. 18C, the cut-out area from which the projection image data is cut out is an increase in the projection angle θ (Δθ ₁ + Δθ ₂ ) from the cut-out area 201a specified at the time of FIG. ) Is moved to the cutout area 201c.

  18A to 18C will be compared. When a virtual projection image (referred to as a virtual projection image) when it is virtually assumed that an image of the entire input image data 200 has been projected is considered, the state of FIG. 18B corresponds to the state of FIG. Thus, the projection position of the virtual projection image is raised according to the change in the projection angle θ. On the other hand, in the state of FIG. 18C, the cutout region moves in the input image data 200 according to the change of the projection angle θ (cutout region 201c), and virtual projection is performed with respect to the state of FIG. The projection position of the image has not changed.

  Therefore, when the projection image changes from the state of FIG. 18B to the state of FIG. 18C, the projection position of the virtual projection image returns to the initial position, that is, the projection position of FIG. Therefore, when this operation is repeated, the projection image appears to the user as if it is vibrating up and down at the frame period.

  The phenomenon that the projected image appears to vibrate up and down in the frame period is reduced as the change in the projection angle θ is made slower. However, even if the change in the projection angle θ is slow, vibration due to an error based on the resolution of the change in the projection angle θ corresponding to the drive pulse for driving the motor 40 remains. Considering that the human eye's ability to detect minute movements is higher than that for large movements, even if the vibration caused by this error is a few lines of vibration, it is recognized by the user as image blurring. There is a possibility that.

  Therefore, in the first method for improving the quality of the projected image according to the present invention, by restricting the resolution of the change in the projection angle θ, the above-described blurring of the user with respect to the projected image is suppressed. To do. More specifically, the resolution of the projection angle θ by the drive pulse for driving the motor 40 is defined based on the angle of view α of the projection lens 12 and the size of the effective area in the display element 114 in units of pixels.

  This will be described more specifically with reference to FIG. FIG. 19 schematically shows how the projection image 220 is projected from the projection lens 12. In FIG. 19, the projection lens 12 projects a projected image 220 at an angle of view α.

  When the vertical size in the maximum effective area of the display element 114 is the number of lines ln, the angle per line in the angle of view α of the projection lens 12 is represented by an angle (α / ln). In the example of FIG. 19, for example, an angle (α / ln) from the center of the projection lens 12 is an angle at which the nth line and the (n + 1) th line are expected.

  On the other hand, the motor 40 rotates at a predetermined angle (step angle) with one drive pulse. As described above, the rotation of the motor 40 is transmitted to the gear 35 through the gear group including the worm gear 41, the gears 42 a and 42 b that transmit the rotation by the worm gear 41, and the gear 43, and the drum 30 is rotated. Accordingly, the drum 30 is also rotated by a predetermined angle λ with one drive pulse for the motor 40, and the projection direction of the projection lens 12 is changed by the angle λ. Therefore, the angle λ is the resolution of the change in the projection angle θ in the rotation control of the motor 40. In other words, the angle λ is the minimum variable angle of the projection angle θ in the rotation control of the motor 40. This angle λ is a value determined by the step angle of the motor 40 and the gear ratio of the gear group including the gear 35.

In the first method for improving the quality of the projected image, the relationship between the angle (α / ln) and the angle λ is defined as in the following equation (10). However, the angle λ is an angle exceeding 0 °.
λ ≦ α / ln (10)

  According to Expression (10), the amount of movement of the projection image for each drive pulse with respect to the motor 40 is one line or less. Therefore, when the projection angle θ by the projection lens 12 is continuously changed, it is possible to suppress the recognition of the user's blurring with respect to the projection image as described above, and to improve the image quality of the projection image. It becomes.

As described above, the optical system of the projector apparatus 1 includes the optical zoom mechanism, and the size of the projected image can be enlarged or reduced by changing the angle of view α by the optical zoom. In the optical zoom, when the angle of view α is the lower limit angle (minimum angle of view α _MIN ) in the optical system, the projected image is the smallest, and the angle per line in the angle of view of the projection lens 12 is also minimized. ,preferable.

Therefore, when the angle λ is determined as an angle satisfying the above-described equation (10) when the angle of view α is the minimum angle of view α _MIN , the change in the projection angle θ per drive pulse is determined by the optical zoom. When the angle is changed, it is always within an angle per line, so that the vertical vibration of the projected image can be efficiently suppressed, and the above-described blurring of the user with respect to the projected image can be suppressed.

<High-quality projection image (2)>
Next, a second method for improving the quality of the projection image according to the first embodiment will be described. As described above, in the projector device 1 according to the first embodiment, the projection image data is read from the memory 101 and the display element 114 is updated for each vertical synchronization signal VD, that is, at a frame period. .

  On the other hand, in the projector device 1, for example, when the projection angle θ is changed at a high speed, it is necessary to supply a plurality of drive pulses to the motor 40 within the frame period. In this case, within one frame period, the projection image is not updated, and only the projection angle θ, that is, the projection position, changes stepwise. Therefore, when the projection image is updated at the head of the next frame, the projection image at each projection position that has changed stepwise in the previous frame is observed by the user as an afterimage.

The afterimage phenomenon will be schematically described with reference to FIG. FIG. 20A shows the vertical synchronization signal VD. For example, the projection image is updated at the timing of the rising edge of the vertical synchronization signal VD. FIG. 20B shows drive pulses for the motor 40. In this example, four times, by the driving pulse pl _11, pl _12, pl ₁₃ and pl ₁₄ having a predetermined pulse width, equal to the time interval between the driving pulses pl ₁₁ through PL ₁₄ within one frame period motor 40 is given. More specifically, the rotation control unit 104 (see FIG. 4) generates a drive pulse pl ₁₁ at the timing of the vertical synchronization signal VD ₁ and gives it to the motor 40, and thereafter drives at equal intervals (equal time intervals). Pulses pl ₁₂ , pl ₁₃ ,... Are sequentially generated and given to the motor 40.

FIG. 20C schematically shows a state in which the projection image is projected onto the projection medium, and the vertical axis in the figure indicates the height of the projection position h. In addition, a projection position is shown on the basis of the lower end of a projection image. Projection image 230 ₁ is updated at the timing of the first vertical synchronizing signal VD ₁ is projected at the same position h ₀ to the next drive pulse pl _12, the projection position projection angle in the driving pulses pl ₁₂ theta is changed It is moved to the next position h ₁ . Similarly, the projected image 230 _1, the projection position at the next driving pulse pl ₁₃ is moved from the position h ₁ to the position h _2, it is moved to further position h ₃ in the next drive pulse pl _14.

The drive pulse of the next frame period beginning is generated at the timing of the next vertical synchronizing signal VD _2. Therefore, the projection image 230 ₁ is updated to the projection image 230 ₂ and the projection position is moved to the position h ₄ .

FIG. 20D is a schematic diagram schematically showing an afterimage based on the projection image. As in FIG. 20C, the vertical axis in the figure indicates the height of the projection position h. As shown in FIG. 20C, the projection position of the projection image 230 ₁ is sequentially moved for each drive pulse at positions h ₀ , h ₁ ,. Further, with the timing of the vertical synchronizing signal VD ₂ is updated from the projection images 230 ₁ to the projection image 230 _2, the projection position by the driving pulse is moved to the position h _4. Therefore, in the portion a where the projection image 230 ₁ at each position h _{0 to} h ₃ before being updated by the vertical synchronization signal VD ₂ does not overlap the projection image 230 ₂ , the position h _{0 to} h is indicated to the user. afterimage by the projection image 230 ₁ of ₃ is likely to be observed.

In this case, the time intervals between the drive pulses pl ₁₁ , pl ₁₂ ,... Are equal, and the projection images 230 _{1 at} the positions h _{0 to} h ₃ are observed by the user to the same extent. Therefore, strength is substantially equal afterimage image by the projection image 230 ₁ of each position h ₀ to h _3, there is a possibility that the residual image is observed as an image, such as blurred.

  Therefore, in the second method for improving the quality of the projection image according to the present invention, when generating the drive pulse within the frame period, the timing between the timing at which the projection image is updated and the drive pulse adjacent to the timing is used. At least a part of the time interval and the time interval between the drive pulses adjacent to each other is made unequal. Thereby, when a projection position changes with a drive pulse within one frame period, a projection image of a specific projection position comes to be projected longer than projection images of other projection positions. The projected image is observed by the user for a longer time. For this reason, the intensity of the afterimages by the projection images at the respective projection positions becomes uneven, and blurring of the images due to the afterimages is suppressed.

FIG. 21 shows an example of motor control by the second method for improving the quality of the projected image. 21A shows a vertical synchronization signal VD, FIG. 21B shows a drive pulse, FIG. 21C shows a projected image, and FIG. 21D shows an afterimage. In the example of FIG. 21, as shown in FIG. 21B, four drive pulses pl ₂₁ , pl ₂₂ , pl _23, and pl ₂₄ within one frame period are divided into four at equal intervals within one frame period. In this example, the drive pulses are generated at an interval of ½ compared to the case of generating the drive pulses. More specifically, the rotation control unit 104 generates the first drive pulse pl ₂₁ at the timing of the vertical synchronization signal VD ₁ . Then, the other drive pulses pl ₂₂ , pl _23, and pl ₂₄ are moved toward the second half of the frame period by the vertical synchronization signal VD ₁ to generate four drive pulses at equal intervals within one frame period. Are generated at intervals of 1/2.

In this case, as shown in FIG. 21C, the projection image 232 ₁ is updated at the timing of the vertical synchronization signal VD ₁ , and the projection image 232 ₁ is at the position h ₀ with the drive pulse pl ₂₁ at the timing. Projected. The projection image 232 ₁ continues to be projected at the position h ₀ during the time T ₁ until the next drive pulse pl ₂₂ . Then, the projection position in the drive pulse pl ₂₂ is moved from the position h ₀ to a position h _1, between the driving pulses pl ₂₂ time T _2, a position h ₂ and the position from the position h ₁ by the driving pulses pl ₂₃ and pl ₂₄ to h _3, sequentially, the projection position is moved. Therefore, the projection image 232 ₁ at each position h _{0 to} h ₃ before being updated by the vertical synchronization signal VD ₂ is observed so as to overlap the projection image 232 ₂ . When attention is paid to a portion where the projection image 232 ₁ and the projection image 232 ₂ do not overlap, the image in the portion b in FIG. 21D is observed as an afterimage during the display period of the projection image 232 ₂ .

In this case, the user, the projected image 232 ₁ of the total observation time of each position h ₁ to h ₃ (time T ₂₎ longer than (time T _1), on observing the projection image 232 ₁ position h ₀ Become. Therefore, as the afterimage, the one at the position h ₀ is mainly observed, and the other images at the other positions h _{1 to} h ₃ are observed very little. Therefore, it is possible to more efficiently suppress image blur due to an afterimage.

FIG. 22 shows another example of the driving pulse by the second method for improving the quality of the projected image. FIG. 22A shows the vertical synchronization signal VD. FIG. 22B shows an example in which two drive pulses pl ₃₁ and pl ₃₂ are generated within one frame period. In this case, the rotation control unit 104 generates the drive pulse pl ₃₁ at the timing of the first vertical synchronization signal VD, and generates the drive pulse pl ₃₂ in the middle of the frame period. The projection position of the projection image updated at the timing of the first vertical synchronization signal VD is moved according to the drive pulse pl ₃₂ .

At this time, the rotation control unit 104 generates the drive pulse pl ₃₂ at a timing shifted backward from the center of the frame period, the interval a from the beginning of the frame period to the drive pulse pl ₃₂ , and the drive pulse pl _32. And the interval b from the frame period to the rear end of the frame period are made unequal. Thereby, since the projection image projected in the space | interval a is observed by the user for a longer time than the projection image projected in the space | interval b, the blur of the image by an afterimage can be suppressed. As described above, when at least two drive pulses are generated within one frame period, the second method for improving the quality of the projected image can be applied.

FIG. 22C illustrates the case where four drive pulses are generated within one frame period described with reference to FIG. 21, and the drive pulses pl _{42 to} pl ₄₄ other than the drive pulse pl _{41 at} the timing of the vertical synchronization signal VD. This is an example in which the time interval is further shortened (interval d). That is, the time ratio in one frame period is larger in the interval c in FIG. 22C than in the time T _{1 in} FIG. Therefore, it is possible to more effectively suppress blurring of an image due to an afterimage as compared with the example of FIG.

  In the above description, the time interval between the drive pulses is set longer in the first half of one frame cycle. However, this is not limited to this example, and the time interval between the drive pulses is increased in the second half of one frame cycle. May be. Also, when one drive pulse is generated within one frame period, the time interval between the update timing of the projected image and the drive pulse may be made unequal. More specifically, the drive pulse is arranged not in the position of the 1/2 frame period but in the vicinity including the coincidence with the update timing of the projection image. Thereby, the blur of the image by an afterimage can be suppressed.

<Setting of projection prohibition period>
In the above description, the projection image is projected through one frame period. However, this is not limited to this example, and the projection that prohibits projection of the projection image according to the timing of the drive pulse within one frame period. A prohibition period can be set. The projection prohibition period excludes the time interval between the timing at which the projection image is updated and the drive pulse adjacent to the timing or the time interval between the adjacent drive pulses is the largest within one frame period. Set for the period.

This projection prohibition period will be described more specifically with reference to FIG. FIG. 23A shows the vertical synchronization signal VD. FIG. 23B shows drive pulses. Here, as in FIG. 21B, four drive pulses pl ₂₁ , pl ₂₂ , pl _23, and pl ₂₄ are generated at equal intervals within one frame period in one frame period. It is generated at a time interval of ½ compared to the case.

In the example of FIG. 23B, the time interval (time T ₁ ) between the drive pulse pl ₂₁ and the drive pulse pl ₂₂ in the frame period of the vertical synchronization signal VD ₁ is adjacent to the drive pulse in the frame period. The time interval between them is the largest period. For this reason, the period from the drive pulse pl ₂₂ to the rear end of the frame period (time T ₂ ) excluding this period is set as the projection prohibited period. The projection prohibition period can be specified using a mask signal as exemplified in FIG. In the example of FIG. 23C, the mask signal designates the projection prohibition period by the mask period 240 in the high state.

  There are various methods for prohibiting the projection of the projection image during the projection prohibition period. FIG. 24-1 shows an example of a configuration of a projector apparatus 1A configured to prohibit projection during the projection prohibition period by controlling lighting of the light source 111. In FIG. 24-1 and FIGS. 24-2, 24-3, and 24-4, which will be described later, portions common to those in FIG. To do.

  In FIG. 24A, the rotation control unit 104 generates a drive pulse based on the vertical synchronization signal VD supplied from the timing generator 107 and supplies it to the rotation mechanism unit 105. At the same time, the rotation control unit 104 generates a mask signal based on the generated drive pulse and supplies the mask signal to the light source 111. The light source 111 is controlled to be turned off during the mask period 240 of the mask signal and turned on during a period other than the mask period 240.

  FIG. 24-2 shows an example of a configuration of a projector apparatus 1B that prohibits projection during the projection prohibition period by switching on / off of driving of the display element 114. The rotation control unit 104 supplies a mask signal generated according to the drive pulse to a drive circuit (not shown) that drives the display element 114. For example, the drive circuit drives the display element 114 so that all pixels are forcibly displayed black in the mask period 240 of the mask signal, and the image data supplied from the image processing unit 102 in periods other than the mask period 240 Accordingly, the display element 114 is driven.

  FIG. 24-3 shows an example of a configuration of a projector apparatus 1C in which a shutter 115 is provided for the projection lens 12, and projection is prohibited during the projection prohibited period by switching between opening and closing of the shutter 115. When the shutter 115 is in the closed state, the shutter 115 blocks light emitted from the projection lens 12 and prohibits projection of the projected image. The shutter 115 may be a mechanical shutter that mechanically blocks light, or may be a system that blocks light by controlling the light transmittance and transmission direction, such as a liquid crystal shutter.

  The rotation control unit 104 supplies a mask signal generated according to the drive pulse to a shutter drive unit (not shown) that drives the shutter 115. For example, the shutter driving unit drives the shutter 115 so as to be closed during the mask period 240 of the mask signal and to be open during periods other than the mask period 240.

  The shutter 115 is not limited to the example provided for the projection lens 12. For example, the shutter 115 may be provided between the light source 111 and the display element 114.

  FIG. 24-4 illustrates an example of a configuration of the projector apparatus 1D in which the image processing unit 102 prohibits projection during the projection prohibited period by inserting a black image whose entire effective area is black. The rotation control unit 104 supplies a mask signal generated according to the drive pulse to the image processing unit 102.

  The image processing unit 102 generates black image data for displaying a black image at the start point of the mask period 240 of the mask signal, replaces the generated black image data with the image data supplied from the image cutout unit 100, and This is supplied to the drive circuit of the display element 114. The black image data may be created in advance and stored in a memory (not shown). Although illustration is omitted, the mask signal is also supplied to the drive circuit of the display element 114, and the drive circuit updates the display of the display element 114 at the start point of the mask period 240 and performs display with black image data.

  Thus, in one frame period, the time interval between the timing at which the projection image is updated and the drive pulse adjacent to the timing, or the period excluding the period in which the time interval between adjacent drive pulses is the largest By prohibiting the projection in step 1, the projection of the projected image having a different position with respect to the projected image projected from the head of the frame within one frame period, for example, which is a cause of the afterimage, is prevented, and the generation of the afterimage is prevented. .

  The projection prohibition period is a part of the time interval between the timing at which the projection image is updated and the drive pulse adjacent to the timing within one frame period, or the time interval between adjacent drive pulses is the longest. Even in a part of the period excluding the large period, an effect of reducing the occurrence of afterimages can be obtained. In addition, in order to compensate for a decrease in luminance due to the provision of the projection prohibition period, for example, a control for increasing the amount of light in the projection period may be added to the light source 111.

<Combination of first method and second method for improving projection image quality>
The first method and the second method for improving the quality of the projected image described above can be used in combination. For example, the change in the projection direction of the projection lens 12 at each of the drive pulses pl ₂₁ , pl ₂₂ , pl _23, and pl ₂₄ shown in FIG. 21B described in the second method follows the above-described equation (10). The step angle of the motor 40 and the gear ratio of the gear group including the gear 35 are determined so that the determined angle λ is obtained.

<Second Embodiment>
Next, a second embodiment will be described. In the first embodiment described above, the drum unit 10 is rotated in the vertical direction and the projection area is changed in the vertical direction according to the projection angle by the projection lens 12, but this is not limited to this example. In the second embodiment, the projection area by the projection lens 12 can be changed in the horizontal direction.

  FIG. 25 is a diagram illustrating an example of the appearance of an image projection apparatus (projector apparatus) 1 ′ according to the second embodiment. FIG. 25 shows a state in which the cover of the image projection apparatus 1 ′ is removed, and the same reference numerals are given to the same parts as those in FIGS. 1 and 2 described above, and the detailed description is omitted.

  In the projector apparatus 1 ′, a horizontal rotary casing 300 is attached to a turntable 301 provided on a pedestal 302. In the horizontal rotating case 300, the drum 30 including the projection lens 12 therein is attached so as to be rotatable in the vertical direction around the shaft portion 38. In accordance with the rotation of the turntable 301, the horizontal rotating casing 300 rotates in the horizontal direction, and accordingly, the projection direction by the projection lens 12 changes in the horizontal direction.

  FIG. 26 shows an example of the appearance of the pedestal 302. The pedestal 302 includes a turntable 301. The turntable 301 has a gear 304 attached to the back side. The turntable 301 rotates in the horizontal direction about the shaft 303 by rotation transmitted from the drive unit 313 described later via the gear 304. The pedestal 302 is provided with various circuit boards and a power supply unit.

  FIG. 27 is a view of the turntable 301 as viewed from the back side. The drive unit 313 transmits the rotation to the gear 304 and rotates the turntable 301. More specifically, the drive unit 313 includes a motor 320 that is, for example, a stepping motor, and is a worm gear 321 that is directly driven by a rotation shaft of the motor 320, a gear 322 that transmits rotation by the worm gear 321, and a transmission from the gear 322. And a gear group including a gear 323 for transmitting the rotated rotation to the gear 304 of the turntable 301. By transmitting the rotation of the motor 320 to the gear 304 by this gear group, the turntable 301 can be rotated according to the rotation of the motor 320. The rotational speed of the turntable 301 is determined by the rotational speed of the motor 320 and the gear ratio of the gear group.

  Projections 312 a and 312 b are provided for the turntable 301. By detecting the protrusions 312a and 312b using a photo interrupter (not shown), the direction of the turntable 301 with respect to the reference direction can be known.

  In the following, when the projection direction of the projection lens 12 is perpendicular to the first surface, the projection angle in the horizontal direction by the projection lens 12 is set to a projection angle of 0 °, and this projection angle of 0 ° is set as an initial value. To do. The projection angle by the projection lens 12 is assumed to increase clockwise when viewed from the upper surface side of the turntable 301.

  Note that the configuration for controlling the operation of the projector apparatus 1 ′ and the configuration of the optical system including the projection lens 12 are the same as those of the circuit unit and the optical engine unit 110 shown in FIG. Omitted. Here, in the second embodiment, the rotation mechanism unit 105 in FIG. 4 includes the driving unit 313, the protrusions 312a and 312b described with reference to FIG. 27, and a photo interrupter (not shown). The output of the photo interrupter is supplied to the rotation control unit 104 in FIG. The motor 320 of the drive unit 313 is driven by a drive pulse supplied from the rotation control unit 104 of FIG.

  The operation of the projector device 1 ′ according to the second embodiment will be schematically described with reference to the configuration of FIG. 4. In the following description, it is assumed that the drum 30 does not rotate in the vertical direction.

  For example, image data shaped into a predetermined image size is input to the projector apparatus 1 'as input image data. Here, the image size of the input image data is assumed to be larger than the width of the display element 114. This input image data is stored in the memory 101 via the image cutout unit 100. FIG. 28 shows the input image data 330 stored in the memory 101 and the projection image data 331 cut out from the input image data 330 by the image cutout unit 100 in accordance with the designation of the image control unit 103 according to the second embodiment. An example of the relationship is shown schematically.

  At the projection angle of 0 °, the image control unit 103 sets the cutout area 331 of the input image data 330 stored in the memory 101 to the image cutout unit 100 according to the information on the projection angle θ acquired from the rotation control unit 104. specify. For example, at a projection angle of 0 °, the image control unit 103 designates an image region 331 a having a width corresponding to the effective region of the display element 114 from the left end of the input image data 330 to the image cutout unit 100.

  The image cutout unit 100 cuts out the image area 331a designated as the cutout area from the input image data 330 stored in the memory 101, and outputs it as image data. This image data is supplied to a drive circuit that drives the display element 114 via the image processing unit 102. The drive circuit drives the display element 114 according to the supplied image data. Thereby, the projection image of the image area 331a is projected onto the projection medium such as a wall or a screen.

  For example, when a change of the projection angle θ is instructed by a user operation on the operation unit 14, the rotation control unit 104 generates a drive pulse for driving the motor 320 in accordance with a command from the CPU 120 according to the instruction, and the rotation mechanism unit. It supplies to 105. In the rotation mechanism unit 105, the motor 320 is driven by the supplied drive pulse, and the turntable 301 is rotated by an angle corresponding to the drive pulse.

The drive pulse is also supplied from the rotation control unit 104 to the image control unit 103. The image control unit 103 designates a cutout region for the input image data 330 stored in the memory 101 in accordance with the drive pulse. Here, the image control unit 103, in response to changes in the incident angle θ corresponding to the drive pulse, x ₁ pixel relative to the image area 331a, specified as a region cut out image region 331b which moves in the horizontal direction.

  The image cutout unit 100 cuts out the image area 331b from the input image data 330 stored in the memory 101 and outputs it as image data. This image data is supplied to the drive circuit of the display element 114 via the image processing unit 102, and the display element 114 is driven. Thereby, the projection image of the image area 331b is projected onto the projection medium at a position moved by the change of the projection angle θ with respect to the projection image of the image area 331a.

Further, when an instruction to change the projection angle θ is given, similarly, the turntable 301 is rotated by an angle corresponding to the drive pulse under the control of the rotation control unit 104 to change the projection angle θ. At the same time, the image control unit 103, in response to changes in the incident angle theta, for example further x ₂ pixels on the image area 331b, the image area 331c that moves in the horizontal direction is designated as the cutout region. A projected image based on the image data in the image area 331c is projected onto the projection medium.

  Thus, according to the projector device 1 ′ of the second embodiment, the input image data 330 whose width is larger than the width of the display element 114 is moved in a horizontal direction in a predetermined area in the input image data 330. All can be projected.

<Application of high quality projection image (1)>
The first method for improving the quality of the projected image in the first embodiment described above can be applied to the second embodiment. In this case, the cutout area for cutting out the projected image moves in the horizontal direction with respect to the input image data 330 as the turntable 301 rotates. Therefore, when the projection angle θ by the projection lens 12 is continuously changed, the blur due to the error based on the resolution of the projection angle θ as described above is recognized by the user in the horizontal direction. Therefore, by applying the first method for improving the quality of the projected image described above to the second embodiment, the recognition of the blurring of the user with respect to the projected image in the horizontal direction is suppressed.

  Here, the angle of view α of Expression (10) described above is an angle at which the effective area is projected from the projection lens 12 in the horizontal direction when the display element 114 projects an image of the maximum effective area in the horizontal direction.

  Further, the number of lines ln in the equation (10) is the horizontal size of the effective area of the display element 114. That is, in the second embodiment, in each horizontal pixel column in the effective region of the display element 114, a pixel column composed of pixels corresponding to vertical positions is defined as a line, and the display element 114 of this line is defined as the line. The number in the maximum effective area in the horizontal direction at is the number of lines ln.

  Furthermore, the angle λ in Expression (10) is an angle at which the projection direction of the projection lens 12 changes in the horizontal direction with one drive pulse for the motor 320. In other words, the angle λ is the minimum variable angle in the rotation control of the motor 320 of the projection angle θ. Similarly to the above, the angle λ is a value determined by the step angle of the motor 320 and the gear ratio of the gear group including the gear 304.

  When the angle of view α, the number of lines ln, and the angle λ defined as described above satisfy the above-described Expression (10), the movement amount of the projection image for each drive pulse with respect to the motor 320 is less than one line. For this reason, when the projection angle θ by the projection lens 12 is continuously changed, it is possible to suppress the user's recognition of the shake with respect to the projection image, and it is possible to improve the image quality of the projection image.

<Application of high quality projection image (2)>
The second method for improving the quality of the projected image in the first embodiment described above can be applied to the second embodiment. Even when the projection direction of the projection lens 12 is changed in the horizontal direction, as in the case of the first embodiment, when the drive pulse is supplied to the motor 320 within the frame period, within one frame period, Only the projection position changes stepwise without updating the projection image. Therefore, when the projection image is updated at the head of the next frame, the projection image at each projection position that has changed in stages in the previous frame is observed by the user as an afterimage in the horizontal direction.

  Also in the second embodiment, as in the first embodiment, when a drive pulse is generated within a frame period, a time between a timing at which a projection image is updated and a drive pulse adjacent to the timing is updated. By making at least a part of the interval and the time interval between the drive pulses adjacent to each other non-uniform, the intensity of the afterimage due to the projection image at each projection position becomes nonuniform, and the image blur due to the afterimage Can be suppressed.

  At that time, similarly to the case of the first embodiment, the time interval between the timing at which the projected image is updated and the drive pulse adjacent to the timing or adjacent to each other within one frame period. A projection prohibition period in which projection of a projection image is prohibited can be set in accordance with the timing of the drive pulse with respect to the period excluding the period having the largest time interval between the drive pulses. As a result, for example, projection of a projected image having a different position with respect to a projected image projected from the head of the frame within one frame period, for example, which is a cause of afterimage, is prevented, and generation of an afterimage is prevented.

  The method of prohibiting the projection of the projection image during the projection prohibition period includes the method of controlling the lighting of the light source 111 and the method of switching the driving of the display element 114 described with reference to FIGS. Any of the method using the shutter 115 and the method of inserting a black image can be applied.

<Combination of first method and second method for improving projection image quality>
Also in the second embodiment, similarly to the above-described first embodiment, the first method and the second method for improving the quality of the projected image can be used in combination. For example, the change in the projection direction of the projection lens 12 at each of the drive pulses pl ₂₁ , pl ₂₂ , pl _23, and pl ₂₄ shown in FIG. 21B described in the second method follows the above-described equation (10). The step angle of the motor 320 and the gear ratio of the gear group including the gear 304 are determined so that the determined angle λ is obtained.

DESCRIPTION OF SYMBOLS 1,1 'Projector apparatus 10 Drum part 12 Projection lens 14 Operation part 20 Base 30 Drum 32 Drive part 35,42a, 42b, 43,304,322,323 Gear 40,320 Motor 41,321 Warm gear 50a, 50b Photo reflector 51a, 51b Photo interrupter 100 Image cutout unit 101 Memory 102 Image processing unit 103 Image control unit 104 Rotation control unit 105 Rotation mechanism unit 106 Angle of view control unit 107 Timing generator 110 Optical engine unit 114 Display element 115 Shutter 120 CPU
140 Image data 300 Horizontal rotating case 301 Turntable 302 Pedestal

Claims (5)

A light modulation element that modulates light in pixel units according to image data;
A projection unit for projecting light modulated by the light modulation element;
An angle-of-view deriving unit for deriving an angle of view at which the projection unit projects the light modulated by the light modulation element;
A projection direction changing unit that changes the projection direction of the projection unit from the first projection direction to the second projection direction based on the minimum variable angle; and
A projection angle deriving unit for deriving a projection angle between the first projection direction and the projection direction changed by the projection direction changing unit;
A storage unit for storing input image data input;
When the projection unit projects from the first projection direction to the second projection direction, as the image data projected by the projection unit, based on the angle of view and the projection angle, the storage unit An image cutout unit that generates cutout image data obtained by cutting out a partial area of the image of the input image data stored in a predetermined cycle,
The image projection apparatus according to claim 1, wherein the minimum variable angle is determined based on the angle of view and a size of an effective region in which light modulation elements modulate light in pixel units. The image projection apparatus according to claim 1, wherein the minimum variable angle is greater than 0 ° and is within the angle of view per pixel of the light modulation element. The angle of view is variable,
The image projection apparatus according to claim 2, wherein the minimum variable angle is determined based on the minimum angle of view. The image projection apparatus according to claim 2, wherein the minimum variable angle is determined based on a size of the maximum effective area. An angle-of-view derivation step in which a projection unit that projects light modulated by a light modulation element that modulates light in pixel units according to image data derives an angle of view for projecting light modulated by the light modulation element;
A projection direction changing step for changing the projection direction of the projection unit from the first projection direction to the second projection direction based on the minimum variable angle;
A projection angle derivation step for deriving a projection angle between the first projection direction and the projection direction changed in the projection direction change step;
A storage step for storing the input image data input;
When the projection unit projects from the first projection direction to the second projection direction, as the image data projected by the projection unit, based on the angle of view and the projection angle, the storing step An image cutout step for generating cutout image data obtained by cutting out a partial area of the image of the input image data stored in step
The image projection method according to claim 1, wherein the minimum variable angle is determined based on the angle of view and a size of an effective area in which the light modulation element modulates light in a pixel unit.

Images