JP2016058897A - Image projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image projection device that can detect a stable projection image during black insertion.SOLUTION: An image forming apparatus includes: light modulation means for modulating light from light source means; projection means for projecting the light modulated by the light modulation means as a projection image; image insertion means for inserting predetermined images into partial areas of the projection image different from each other at different timings in at least one frame of a plurality of frames of the projection image; and control means for controlling a timing at which detection means detects the projection image so that the predetermined images are inserted into the respective partial areas in the same period of time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image projection apparatus such as a liquid crystal projector, and more particularly to a method for detecting a projected image.

  2. Description of the Related Art Conventionally, a method for improving motion blur using a technique called black insertion (black insertion method) is known. The black insertion method is a method of inserting black in a subframe period in a display device using a hold type display device such as a liquid crystal panel. The subframe period is a period obtained by dividing one frame period into a plurality of periods.

  Patent Document 1 discloses a method for controlling the extinction / lighting timing of a plurality of light source blocks based on the scanning start timing of black image display as a black insertion method. Patent Document 2 discloses a method for capturing an image that is time-divisionally projected for each of a plurality of color components as a method for capturing a projected image.

JP 2009-244717 A JP 2006-094445 A

  However, in the techniques disclosed in Patent Documents 1 and 2, taking a projected image during black insertion is not considered. For this reason, if a projected image is shot during black insertion, the imaging result is affected by black insertion, and only subframes are picked up. There is. As a result, if processing such as autofocus, keystone correction, and color correction is performed based on the imaging result, there is a possibility of malfunction.

  Therefore, the present invention provides an image projection apparatus capable of detecting a stable projection image when black is inserted.

  An image projection apparatus according to one aspect of the present invention includes a light modulation unit that modulates light from a light source unit, a projection unit that projects modulated light from the light modulation unit as a projection image, and a plurality of frames of the projection image. In at least some of the frames, the image insertion means for inserting a predetermined image into different partial areas of the projection image at different timings, and the insertion time of the predetermined image in each of the partial areas are made equal. Control means for controlling the detection timing of the projection image by the detection means.

  An image projection apparatus according to another aspect of the present invention includes: a light modulation unit that modulates light from a light source unit; a projection unit that projects modulated light from the light modulation unit as a projection image; and a plurality of frames of the projection image. And at least some of the frames, an image insertion unit that inserts a predetermined image into different partial areas of the projection image at different timings, and does not include an insertion time of the predetermined image in each of the partial areas Control means for controlling the detection timing of the projection image by the detection means.

  Other objects and features of the invention are described in the following embodiments.

  ADVANTAGE OF THE INVENTION According to this invention, the image projection apparatus which can detect the stable projection image in the case of black insertion can be provided.

It is a block diagram of the image projection apparatus in a 1st embodiment. It is a timing chart which shows the operation | movement sequence in 1st Embodiment. It is a flowchart which shows the control method in 1st Embodiment. It is a timing chart which shows the operation sequence in a 2nd embodiment. It is a flowchart which shows the control method in 2nd Embodiment. It is a block diagram of the image projection apparatus in 3rd Embodiment. It is a flowchart which shows the control method in 3rd Embodiment. It is a flowchart which shows the sensing start timing calculation method in 3rd Embodiment. It is a timing chart which shows sensing start operation in a 3rd embodiment. It is a timing chart which shows the sensing start operation | movement after the sub-frame change in 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
First, an AF process during black insertion by the image projection apparatus according to the first embodiment of the present invention will be described with reference to FIGS. In addition, although the image projection apparatus of this embodiment performs AF processing using an image sensor, it is not limited to this.

  FIG. 1 is a block diagram of a projector 1 (image projection apparatus) in the present embodiment. The projector 1 is an image projection apparatus that projects light modulated by the panel 62 in accordance with an input image signal onto a projection surface such as a screen as a projection image via a projection lens 80 as projection means. The projector 1 includes a video signal input unit 10, an image processing engine 20, a control microcomputer 30, an operation unit 40, a light source unit 50, a light modulation unit 60, an image sensor 70, and a projection lens 80. The video signal input unit 10 receives a single or a plurality of video signals.

  The image processing engine 20 is an image processing unit that performs various image processing and synchronization timing change on the input video signal from the video signal input unit 10 and outputs the processed output video signal to the panel driving unit 61. The image processing engine 20 can output an internally generated image as an output video signal regardless of the presence or absence of an input signal. The image processing engine 20 includes an update cycle determination unit 21. The update cycle determination unit 21 determines a frame buffer update cycle that is updated at a predetermined cycle. Here, the frame buffer update cycle is an update cycle of a frame buffer formed by storing an input video signal or an internally generated image on a memory. The update cycle determination unit 21 determines the frame buffer update cycle based on the vertical synchronization signal of the input video and the internal generation timing, and outputs the frame buffer update signal to the control microcomputer 30.

  The control microcomputer 30 is a control unit configured by a microcomputer so as to control each unit of the projector 1 in accordance with an input from the operation unit 40. The control microcomputer 30 includes a subframe generation unit 31, a subframe insertion unit 32, and a sensing timing control unit 33. Based on the signal output from the update cycle determination unit 21, the subframe generation unit 31 divides one cycle of the frame buffer update cycle into a plurality of subframe periods, and generates a subframe start signal. The subframe insertion unit 32 functions as a subframe insertion unit that controls the light source driving circuit 51 in synchronization with the subframe start signal generated by the subframe generation unit 31 and performs black insertion processing corresponding to each subframe. To do. The sensing timing control unit 33 is based on the subframe start signal generated by the subframe generation unit 31 and the imaging timing of the image sensor 70 (light sensing means) so that the black insertion time is uniform in the entire region of the display image. To control.

  The operation unit 40 includes a switch, a button (not shown) that accepts various operations from the user, a remote control light receiving unit, and the like. The light source unit 50 functions as light source means for generating light to be projected based on the light source drive signal output from the control microcomputer 30. The light source unit 50 includes a light source driving circuit 51 and an LED unit 52. The light source drive circuit 51 outputs a light amount control signal to the LED unit 52 in synchronization with the light source drive signal output from the subframe insertion unit 32. The LED unit 52 includes a plurality of LEDs, and the areas illuminated by the LEDs are different. Each LED is individually controlled in light quantity based on a light quantity control signal output from the light source driving circuit 51.

  The light modulation unit 60 functions as a light modulation unit that modulates light generated by the light source unit 50 based on a signal output from the image processing engine 20. The light modulation unit 60 includes a panel drive unit 61 and a panel 62. The panel drive unit 61 drives the panel 62 based on the panel drive signal output from the image processing engine 20. The panel 62 forms a light modulation pattern based on the signal output from the panel drive unit 61.

  The image sensor 70 functions as an optical sensing unit (imaging unit) that detects reflected light of an image projected by the projector 1. In the present embodiment, two image sensors 70 are arranged on the front surface of the projector 1, and each image sensor 70 picks up an image projected on the projection surface, thereby picking up images 2 taken from different positions. Two two-dimensional image data can be obtained. Two images (two image data) obtained by imaging have different phases depending on the distance to the projected image. The image sensor 70 of the present embodiment uses this phase difference to realize an autofocus function using a phase difference method. In this embodiment, the autofocus function is realized by the phase difference method from two image data having different phases. However, the present invention is not limited to this, and the autofocus function is realized by the contrast method using one image sensor. It may be realized. In the present embodiment, the image sensor 70 (imaging unit) is used as the optical sensing unit. However, the present invention is not limited to this, and other optical sensing units such as a light amount sensor may be used.

  The projection lens 80 functions as a projection unit that forms a projection image from the light from the light modulation unit 60. The projection lens 80 includes a lens position detection unit 81 and a motor 82. The lens position detection unit 81 transmits the position of the focus lens included in the projection lens 80 to the control microcomputer 30. The position of the focus lens can be detected by detecting the rotation angle of the focus ring of the projection lens 80, for example. The rotation angle of the focus ring is transmitted from the lens position detection unit 81 to the control microcomputer 30 by, for example, digital output from a pulse encoder or analog output from a variable resistor. In any transmission method, the position of the focus lens is converted into a digital value by the control microcomputer 30. The motor 82 is an actuator that moves the focus lens included in the projection lens 80 in the optical axis direction of the projection lens 80. The focus state (focus state) of the projection image can be changed by moving the focus lens included in the projection lens 80 by the motor 82.

  Next, the black insertion operation will be described with reference to FIG. FIG. 2 is a timing chart showing an AF operation sequence by the image sensor 70 and the control microcomputer 30 in the present embodiment. As shown in FIG. 2, in this embodiment, the number of subframes in one cycle is five. In subframes 2, 3, and 4, black is inserted in a part of the display image. The black insertion method in each subframe can be realized by setting the light quantity of the LED that illuminates the black insertion region of the display image to zero. Note that the number of subframes, the number of subframes in which black insertion is performed, and the black insertion method in this embodiment are examples, and can be changed as appropriate.

  When black insertion is executed, first, the image processing engine 20 (update cycle determining unit 21) determines the frame buffer update cycle based on the video signal output from the video signal input unit 10, and the control microcomputer 30 Output frame buffer update signal to. Subsequently, the subframe generation unit 31 of the control microcomputer 30 generates a subframe start signal based on the frame buffer update signal. Then, the sub-frame insertion unit 32 outputs a light source driving signal corresponding to the black insertion lighting pattern corresponding to each sub-frame to the light source driving circuit 51 in synchronization with the sub-frame start signal. The light source drive circuit 51 controls the light amount of each LED of the LED unit 52 based on the light source drive signal, and generates a light amount corresponding to the black insertion pattern.

  Next, a method for capturing a stable projection image when a projection image is captured during black insertion will be described. When imaging is performed at an arbitrary timing by the image sensor 70, images having different luminances are captured for each black insertion region, as in the image sensor (error) in FIG. This is because the number of black insertions in each region generated during the imaging time is different. In order to avoid such a result, it is only necessary to control the imaging time so that the number of black insertions in each region generated during the imaging time of the image sensor 70 becomes uniform.

  With reference to FIG. 3, a specific example in which a stable captured image is captured using the image sensor 70 during black insertion and autofocus (AF) is performed will be described. FIG. 3 is a flowchart showing a control method (AF control method using the image sensor 70) in the present embodiment. Each step (AF process) in FIG. 3 is executed by the control microcomputer 30 in accordance with a computer program.

  When AF starts, first, in step S101, the control microcomputer 30 starts projecting an AF pattern. The AF pattern is projected onto the projection surface by storing image data corresponding to the AF pattern in the frame buffer. The AF pattern used at this time is preferably an image with high contrast and clear edges. For example, an image in which white and black lines are alternately displayed is used as the AF pattern.

  Subsequently, in step S102, the control microcomputer 30 determines whether or not the subframe 2 start signal (black insertion start signal) output from the subframe generation unit 31 has been detected. When the control microcomputer 30 has not detected the subframe 2 start signal, the control microcomputer 30 repeats the determination in step S102. On the other hand, when the control microcomputer 30 detects the subframe 2 start signal, the control microcomputer 30 proceeds to step S103. In step S <b> 103, the control microcomputer 30 captures a projected image using the image sensor 70. As described above, two image sensors 70 according to the present embodiment are arranged on the front surface of the projector 1. For this reason, by using each image sensor 70 to capture an image projected on the projection surface, two two-dimensional image data captured from different positions can be obtained.

  Subsequently, in step S104, the control microcomputer 30 determines whether or not the subframe 5 start signal (black insertion end signal) output from the subframe generation unit 31 has been detected. If the control microcomputer 30 does not detect the subframe 5 start signal, the control microcomputer 30 returns to step S103 and continues imaging using the image sensor 70. On the other hand, when the control microcomputer 30 detects the subframe 5 start signal, the control microcomputer 30 proceeds to step S105. In step S105, the control microcomputer 30 determines whether the imaging end condition is satisfied. When the imaging end condition is not satisfied, the process returns to step S103, and imaging is continued using the image sensor 70. On the other hand, when the imaging end condition is satisfied, the process proceeds to step S106, and imaging using the image sensor 70 is ended. Here, the images (projected images) taken in steps S102 to S106 have the same number of black insertions in any region in the image. For example, as shown in FIG. 2, the imaging time is set so that the number of black insertions is twice in each area in each of the upper area, the middle area, and the lower area of the projection image. For this reason, a stable image with uniform luminance reduction due to black insertion can be obtained.

  Subsequently, in step S107, the control microcomputer 30 calculates the phase difference between the two images (image data) captured in steps S102 to S106. In step S108, the control microcomputer 30 calculates the position of the focus lens (focus position) based on the phase difference calculated in step S107. The focus position is determined by the distance to the projected image. Further, as shown in the following formula (1), the phase difference and the reciprocal of the distance to the projection image (subject) have a proportional relationship.

(Phase difference) ∝ (1 / Distance to projected image) (1)
For this reason, when the phase difference is determined, the focus position can be calculated. The correspondence between the phase difference and the focus position is assumed to be known. For example, the relationship between the phase difference and the focus position at two distances (short distance and long distance) is stored at the time of manufacture. The focus position corresponding to the phase difference calculated in step S107 can be calculated by linear interpolation from the two points (two distances).

  Subsequently, in step S109, the control microcomputer 30 moves the focus lens in the projection lens 80 to the focus position calculated in step S108. At this time, the control microcomputer 30 drives the motor 82 and monitors the output of the lens position detector 81. When the output of the lens position detector 81 reaches the focus position calculated in step S108, the control microcomputer 30 stops driving the motor 82. In step S110, the control microcomputer 30 stops outputting the AF pattern and ends the AF process.

  Thus, the image projection apparatus (projector 1) of the present embodiment projects light modulation means (light modulation unit 60) that modulates light from the light source means (light source unit 50), and light modulated by the light modulation means. Projection means (projection lens 80) for projecting as an image is provided. The image projection apparatus also includes a frame dividing unit (subframe generation unit 31), an image insertion unit (subframe insertion unit 32), and a control unit (sensing timing control unit 33). The frame dividing unit divides the frame of the projection image into a plurality of subframes (for example, subframes 1 to 5). The image insertion unit is configured to perform different partial areas (for example, an upper area, a middle area, and a lower area) of the projection image at different timings in at least some of the subframes (for example, subframes 2 to 4). A predetermined image is inserted into three partial areas). The control means controls the detection timing of the projected image by the detection means (image sensor 70) so that the insertion times of the predetermined images in each of the partial areas are equal (uniform).

  In the present embodiment, when frame division is not necessary, the frame division unit (subframe generation unit 31) may not be provided. In this case, the image insertion unit (a frame insertion unit corresponding to the sub-frame insertion unit 32) performs predetermined processing on different partial areas of the projection image at different timings in at least some of the plurality of frames of the projection image. Insert an image.

  Preferably, the frame dividing means converts the frame of the projection image into a first subframe (for example, one of subframes 2 to 4) and a second subframe (for example, another one of subframes 2 to 4). Is divided into a plurality of subframes including Then, the image insertion means inserts a predetermined image into the first partial area (one of the three partial areas) of the projection image in the first subframe, and the second portion of the projection image in the second subframe. A predetermined image is inserted into an area (one of the three partial areas).

  Preferably, the light source means has a plurality of light sources capable of emitting light independently of each other so as to illuminate the plurality of partial regions. Then, the image insertion unit controls the plurality of light sources so as to emit a second light amount different from the first light amount set as the projection image in each of the plurality of partial regions. More preferably, the image insertion means inserts a predetermined image (performs black insertion) by setting the second light quantity to zero.

  Preferably, the image insertion unit inserts a second image different from the first image recorded in the frame buffer of the projection image as the predetermined image. More preferably, the image insertion means inserts a black image as the second image (performs black insertion).

  Preferably, the image projection apparatus includes a cycle determination unit (update cycle determination unit 21) that determines a cycle for updating a frame of the projection image, and an input unit (video signal input unit 10) that inputs a video signal. The cycle determining unit determines a periodic timing for storing the input image from the input unit or the image generated inside the image projection apparatus in the memory and forming a frame. Preferably, the detection unit is an imaging unit (image sensor 70) that captures a projected image. More preferably, the imaging unit detects reflected light from the projection surface of the projection image. Preferably, the image projection apparatus includes a focus control unit (control microcomputer 30) that performs autofocus control (AF control) based on an image signal obtained from the detection unit.

  As described above, in the present embodiment, the control microcomputer 30 controls the imaging time so that the number of black insertions in each region in the image generated during the imaging time of the image sensor 70 is uniform (equal). As a result, the degree of luminance reduction due to black insertion is uniform in each region in the image, and a stable image can be obtained. Moreover, a correct phase difference can be calculated by obtaining a stable image. As a result, it is possible to reduce malfunctions and failures of AF processing.

  In the present embodiment, AF processing is performed using an image captured during black insertion, but the present invention is not limited to this. The present embodiment is not limited to AF processing, and can also be applied when performing other processing such as keystone (trapezoid) correction processing. In this case, the image projection apparatus includes keystone control means (control microcomputer 30) that performs auto keystone control based on the image signal obtained from the detection means.

  Further, the black insertion method of the present embodiment is realized by setting the light quantity of the LED that illuminates the black insertion area of the display image to 0, but the present invention is not limited to this, and black is applied to the liquid crystal panel. Black insertion can also be realized using other methods such as displaying.

(Second Embodiment)
Next, with reference to FIGS. 4 and 5, the AF process during black insertion by the image projection apparatus in the second embodiment of the present invention will be described. In the present embodiment, the AF process is performed using an image sensor, but the present invention is not limited to this.

  In the present embodiment, the imaging timing is controlled so that the black insertion period of each region in the image is uniform in that the effective imaging period is only a period during which black insertion is not performed during the imaging period. Different from the embodiment. The basic configuration of the projector (image projection apparatus) of this embodiment is the same as that of the projector 1 of the first embodiment described with reference to FIG.

  With reference to FIG. 4, a method of acquiring a stable projection image when a projection image is captured during black insertion will be described. FIG. 4 is a timing chart showing an AF operation sequence by the image sensor 70 and the control microcomputer 30 in the present embodiment. As shown in FIG. 4, the number of subframes in one cycle is five. In subframes 2, 3, and 4, black is inserted in a partial area of the display image. The black insertion method in each subframe is realized by setting the light quantity of the LED that illuminates the black insertion region of the display image to zero. Note that the number of subframes, the number of subframes in which black insertion is performed, and the black insertion method in this embodiment are examples, and can be changed as appropriate. In the present embodiment, as shown in FIG. 4, during the imaging period using the image sensor 70, a subframe period in which black is not inserted is set as an effective imaging period, and a projection image only in the effective imaging period is captured. Use.

  Next, a specific example in which a stable captured image is captured using the image sensor 70 during black insertion and autofocus (AF) is performed will be described with reference to FIG. FIG. 5 is a flowchart showing a control method (AF control method using the image sensor 70) in the present embodiment. Each step (AF process) in FIG. 5 is executed by the control microcomputer 30 in accordance with a computer program.

  When AF starts, first, in step S201, the control microcomputer 30 starts projecting an AF pattern. Subsequently, in step S202, the control microcomputer 30 determines whether or not a black insertion area is included in the currently displayed subframe, and updates the imaging effective state according to the determination result. Specifically, when a black insertion area is included in the currently displayed subframe, the control microcomputer 30 invalidates the imaging enabled state. On the other hand, when the black insertion area is not included, the imaging valid state is validated.

  Subsequently, in step S203, the control microcomputer 30 determines whether or not the imaging valid state is valid. If the imaging valid state is valid, the process proceeds to step S204. In step S <b> 204, the control microcomputer 30 captures the AF pattern displayed by the image sensor 70. On the other hand, when the imaging valid state is invalid, the process proceeds to step S205. In step S <b> 205, the control microcomputer 30 controls to temporarily stop imaging of the AF pattern displayed by the image sensor 70 and not to perform imaging.

  Subsequently, in step S206, the control microcomputer 30 determines whether or not a subframe start signal is detected. When the subframe start signal is not detected, the process returns to step S203, and steps S204 and S205 are continuously executed. On the other hand, if a subframe start signal is detected, the process proceeds to step S207.

  In step S207, the control microcomputer 30 determines whether the imaging end condition is satisfied. If the imaging end condition is satisfied, the process proceeds to step S208. On the other hand, when the imaging end condition is not satisfied, the process returns to step S202. The imaging end condition can be set as appropriate when the imaging time reaches the specified time or when the effective imaging time reaches the specified time. Subsequent steps S208 to S211 are the same as steps S107 to S110 of the first embodiment described with reference to FIG.

  As described above, in this embodiment, the control unit (sensing timing control unit 33) controls the detection timing of the projected image by the detection unit (image sensor 70) so as not to include the predetermined image insertion time in the partial region. . That is, in the present embodiment, imaging is performed using only the period during which black insertion is not performed during the imaging period of the image sensor 70 as the effective imaging period. As a result, a stable image in which variation in luminance due to black insertion in each region of the captured image is suppressed can be obtained. Moreover, a correct phase difference can be calculated by obtaining a stable image. As a result, it is possible to reduce malfunctions and failures of AF processing. Note that the present embodiment is not limited to the AF process, and can be applied to other processes such as a keystone (trapezoid) correction process.

(Third embodiment)
Next, with reference to FIGS. 6 to 10, an AF process during black insertion by the image projection apparatus according to the third embodiment of the present invention will be described. In this embodiment, AF processing is performed using a stereo camera, but the present invention is not limited to this.

  FIG. 6 is a block diagram of the projector 100 (image projection apparatus) in the present embodiment. The projector 100 has a control microcomputer 300 including a sensing time acquisition unit 334, and differs from the projector 1 in the first embodiment in that a stereo camera 370 is used instead of the image sensor 70. Since the other configuration of the projector 100 is the same as that of the projector 1, the description thereof is omitted.

  Stereo camera 370 functions as an external light image sensor that detects the reflected light of the image projected by projector 100. The stereo camera 370 has two lenses arranged at a constant interval, and can capture two two-dimensional images captured from different positions with one imaging. Stereo camera 370 is external to projector 100 and is configured to be able to communicate with projector 100 by communication means. Communication between the stereo camera 370 and the projector 100 is performed by cable connection or wireless communication (communication means).

  The sensing time acquisition unit 334 of the control microcomputer 300 acquires the imaging time from the stereo camera 370 through communication means. The sensing timing control unit 33 functions as a sensing timing control unit that notifies the stereo camera 370 of the sensing timing. The sensing timing control unit 33 calculates the sensing start timing from the imaging time of the stereo camera 370 acquired by the sensing time acquisition unit 334, and transmits a sensing start notification signal to the stereo camera 370. When the stereo camera 370 receives the sensing start notification signal, the stereo camera 370 starts capturing a projected image. When the imaging is completed, the stereo camera 370 notifies the sensing timing control unit 33 of a sensing end notification signal. The control microcomputer 300 receives the imaging result simultaneously with the sensing end notification signal from the stereo camera 370 by the communication means, and performs AF processing.

  With reference to FIG. 7, a specific example in which a stable captured image is captured using the stereo camera 370 during black insertion and autofocus (AF) is performed will be described. FIG. 7 is a flowchart showing a control method (AF control method using the stereo camera 370) in the present embodiment. Each step (AF process) in FIG. 7 is executed by the control microcomputer 300 according to a computer program.

  When AF starts, first, in step S301, the control microcomputer 300 starts projecting an AF pattern. The AF pattern is projected onto the projection surface by storing image data corresponding to the AF pattern in the frame buffer. The AF pattern used at this time is preferably an image with high contrast and clear edges. For example, an image in which white and black lines are alternately displayed is used.

  Subsequently, in step S302, the sensing time acquisition unit 334 acquires the imaging time (information regarding the imaging time) from the stereo camera 370. In step S303, the sensing timing control unit 33 sets the sensing start timing based on the imaging time acquired in step S302.

  Here, a method for calculating the sensing start timing by the sensing timing control unit 33 will be described with reference to FIGS. FIG. 8 is a flowchart showing the sensing start timing calculation method (step S303) in the present embodiment. FIG. 9 is a timing chart showing the sensing start operation. FIG. 10 is a timing chart showing the sensing start operation after changing the subframe.

  First, in step S303a in FIG. 8, the sensing timing control unit 33 calculates the surplus time based on the sensing time acquired in step S302 and the frame buffer update signal. Here, the surplus time is a time obtained by subtracting an integral multiple of the frame buffer update period from the sensing time (surplus time <frame buffer update period).

  Subsequently, in step S303b, the sensing timing control unit 33 determines whether the black insertion time of each region can be set to be equal with respect to the surplus time calculated in step S303a. If the black insertion times of the respective areas cannot be set to be equal, the process proceeds to step S303c. On the other hand, if it can be set so that the black insertion times of the respective regions are equal, the process proceeds to step S303d. In the present embodiment, the conditions that can be set so that the black insertion times of the respective regions are equal are the cases where the following conditions (1) and (2) are satisfied.

Condition (1): Period in which continuous black insertion is not performed> Surplus time Condition (2): Black insertion time <surplus time As shown in FIG. 9, a period in which continuous black insertion is not performed> Surplus time is satisfied. In this case (when the condition (1) is satisfied), it is possible to set the black insertion time of each region to be equal by setting the sensing start timing to the subframe start signal after the black insertion is completed. Also, as shown in FIG. 9, when the black insertion time <the surplus time is satisfied (when the condition (2) is satisfied), the sensing start timing is set to the black insertion start subframe start signal, so that The black insertion time can be set to be equal.

  In step S303c of FIG. 8, as shown in FIG. 10, the subframe generation unit 31 and the subframe insertion unit 32 set the subframes so that the black insertion time is equal to the surplus time calculated in step S303a. To do. As a subframe setting method, for example, the number of subframes to be divided is changed in the subframe generation unit 31, or the number of subframes to be black inserted is changed in the subframe insertion unit 32, and the subframe start signal is changed. There are methods such as creating. In this embodiment, the subframe start signal is changed by the subframe generation unit 31 and the subframe insertion unit 32. However, the present invention is not limited to this, and the image processing engine 20 changes the frame buffer update period. It can be changed as appropriate.

  In step S303d, the sensing timing control unit 33 sets the timing shown in FIG. 9 as the sensing start timing.

  Subsequently, in step S304 in FIG. 7, the control microcomputer 30 determines whether or not the sensing start timing signal set in step S303 has been detected. If the sensing start timing signal is not detected, step S304 is repeated. On the other hand, when the sensing start timing signal is detected, the process proceeds to step S305. In step S305, the control microcomputer 30 notifies the stereo camera 370 of the start of sensing via the communication unit. Then, the stereo camera 370 starts capturing a projection image.

  Subsequently, in step S306, the control microcomputer 30 determines whether a sensing end notification signal is detected from the stereo camera 370 via the communication unit. If the sensing end notification signal is not detected, step S306 is repeated. On the other hand, when the sensing end notification signal is detected, since the imaging is completed, the process proceeds to step S307.

  In step S307, the control microcomputer 30 receives two imaging results from the stereo camera 370 via the communication unit. Subsequently, in step S308, the control microcomputer 30 calculates the phase difference between the two images captured in steps S302 to S307. In step S309, the control microcomputer 30 calculates the focus position based on the phase difference calculated in step S308. Subsequently, in step S310, the control microcomputer 30 moves the focus lens in the projection lens 80 to the focus position calculated in step S309. At this time, the control microcomputer 30 drives the motor 82 and monitors the output of the lens position detector 81. When the output of the lens position detection unit 81 reaches the focus position calculated in step S309, the control microcomputer 30 stops driving the motor 82.

  Subsequently, in step S311, the control microcomputer 30 determines whether the setting of the subframe has been changed in step S303c. If the subframe setting has been changed, the process proceeds to step S312 to return the subframe setting. On the other hand, if the setting of the subframe has not been changed, the process proceeds to step S313. In step S313, the control microcomputer 30 stops outputting the AF pattern and ends the AF process.

  Thus, in the image projection apparatus (projector 100) of the present embodiment, the detection means is the stereo camera 370 provided outside the image projection apparatus. Preferably, the image projection apparatus includes an acquisition unit (sensing time acquisition unit 334) that acquires a detection time by the detection unit. And a control means (sensing timing control part 33) controls the detection timing of the projection image by a detection means based on the detection time acquired by the acquisition means. More preferably, the frame dividing means (subframe generating unit 31) changes the setting of the subframe according to the detection time.

  As described above, in the present embodiment, the imaging time is controlled based on the imaging time of the stereo camera 370 so that the number of black insertions in each region that occurs during the imaging time is uniform. As a result, even when an external light image sensor is used, the luminance drop due to black insertion is uniform and a stable image can be obtained. Moreover, a correct phase difference can be calculated by obtaining a stable image. As a result, it is possible to reduce malfunctions and failures of AF processing.

  In the present embodiment, AF processing is performed using an image captured during black insertion, but the present invention is not limited to this. The present embodiment is not limited to AF processing, and can also be applied when performing other processing such as keystone (trapezoid) correction processing. In this embodiment, the autofocus function is realized by the phase difference method from the two imaging results using a stereo camera, but the autofocus function is realized by the contrast method from a single imaging result using a normal camera or the like. May be. Further, when performing the keystone correction process or the like, it can be realized by a normal camera instead of the stereo camera 370.

  According to each embodiment, it is possible to provide an image projection apparatus capable of detecting a stable projection image when black is inserted.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

1, 100 Projector (image projection device)
32 Subframe insertion part (image insertion means)
33 Sensing timing control unit (control means)
60 Light modulation unit (light modulation means)
80 Projection lens (projection means)

Claims (15)

Light modulating means for modulating light from the light source means;
Projection means for projecting modulated light by the light modulation means as a projection image;
Image insertion means for inserting predetermined images into different partial areas of the projection image at different timings in at least some of the plurality of frames of the projection image;
An image projection apparatus comprising: control means for controlling the detection timing of the projection image by the detection means so that the insertion times of the predetermined images in each of the partial areas are equal. Light modulating means for modulating light from the light source means;
Projection means for projecting modulated light by the light modulation means as a projection image;
Image insertion means for inserting predetermined images into different partial areas of the projection image at different timings in at least some of the plurality of frames of the projection image;
An image projection apparatus comprising: control means for controlling the detection timing of the projection image by the detection means so as not to include the insertion time of the predetermined image in each of the partial areas. Frame division means for dividing each frame of the projection image into a plurality of subframes;
The image insertion means inserts the predetermined image into the different partial areas of the projection image at different timings in at least some of the plurality of subframes. Or the image projection apparatus of 2. The frame dividing means divides a frame of the projection image into the plurality of subframes including a first subframe and a second subframe,
The image insertion means inserts the predetermined image into the first partial area of the projection image in the first subframe, and inserts the predetermined image into the second partial area of the projection image in the second subframe. The image projection apparatus according to claim 3, wherein the image is inserted. The light source means has a plurality of light sources capable of emitting light independently of each other so as to illuminate the partial area at the different timings,
The image insertion means controls the plurality of light sources so as to emit a second light amount different from the first light amount set as the projection image in the partial region. The image projection apparatus of any one of Claims.   The image projection apparatus according to claim 5, wherein the image insertion unit inserts the predetermined image by setting the second light amount to zero.   The said image insertion means inserts the 2nd image different from the 1st image currently recorded on the frame buffer of the said projection image as said predetermined image, The any one of Claim 1 thru | or 4 characterized by the above-mentioned. The image projection apparatus according to item.   The image projection apparatus according to claim 7, wherein the image insertion unit inserts a black image as the second image. An input means for inputting a video signal;
A period determining means for determining a period for updating the frame of the projection image;
The cycle determining means determines the periodic timing for storing an input image from the input means or an image generated inside the image projection apparatus in a memory and forming the frame. Item 9. The image projection device according to any one of Items 1 to 8.   The image projection apparatus according to claim 1, wherein the detection unit is an imaging unit that captures the projection image.   The image projection apparatus according to claim 10, wherein the imaging unit detects reflected light from a projection surface of the projection image.   The image projection apparatus according to claim 1, wherein the detection unit is a camera provided outside the image projection apparatus. It further has an acquisition means for acquiring a detection time by the detection means,
The image projection apparatus according to claim 12, wherein the control unit controls the detection timing of the projection image by the detection unit based on the detection time acquired by the acquisition unit.   The image projection apparatus according to claim 1, further comprising a focus control unit that performs autofocus control based on an image signal obtained from the detection unit. 15. The image projection apparatus according to claim 1, further comprising keystone control means for performing auto keystone control based on an image signal obtained from the detection means.