JP2019133068A - Projection device, control method and program of the same - Google Patents

Abstract

To provide a projection device that can change a display mode of an image to be displayed on a projection surface due to laser scanning by being tailored to a characteristic of display-purpose data to be projected to the projection surface.SOLUTION: An above-mentioned projection device comprises: input means that inputs image signals; setting means that sets resolution of an image to be displayed on a projection surface; light source means that outputs modulated laser light in accordance with the image signal; and control means that controls an emission direction of the laser light so that, on the projection surface, the laser light scans in a first direction at a prescribed frequency, and scans in a second direction at a frequency in accordance with the set resolution. Herein, the control means is configured to control the emission direction so that, when resolution in the second direction of the set resolution is first resolution, the laser light is caused to scan in the second direction at a first frequency, and when the resolution in the second direction of the set resolution is second resolution higher than the first resolution, the laser light is caused to scan in the second direction at a second frequency lower than the first frequency.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a projection apparatus that displays an image on a projection surface with laser light, a control method therefor, and a program.

  2. Description of the Related Art Conventionally, a laser scanning projector that displays an image on a projection surface by reflecting laser light with a micro mirror of a MEMS (Micro Electro Mechanical Systems) scanner and performing two-dimensional raster scanning is known.

  Laser scanning projectors do not have fixed pixels and do not draw fixed pixels because they control the laser pulse output at the positions corresponding to the pixels on the scanning line to form an image on the projection surface, so that the positions of the pixels to be drawn There is an advantage that it is easy to change.

  Patent Document 1 discloses an image in which when a scanning mirror is vibrated and an image is displayed on a projection surface, pixel drawing timing is controlled based on the vibration of the scanning mirror, and influences due to individual differences in scanning mirrors, environmental temperature, and the like are reduced. A technique for realizing display is disclosed.

JP 2013-140224 A

  By the way, generally, in order to realize a MEMS scanner including a micromirror that operates at high speed, it is necessary to drive the mirror at resonance at a specific frequency. For this reason, characteristics of the MEMS scanner may be determined in accordance with a video format assumed in advance for a laser scanning projector equipped with the MEMS scanner.

  On the other hand, since still image content has various characteristics such as resolution and aspect ratio, when displaying such display data with a laser scanning projector, the resolution and aspect ratio can be flexibly adjusted according to the display data. It is desirable that it can be changed. Further, when displaying still image content or video content that changes slowly, display at a high frame rate is not always necessary, and it may be beneficial to perform flexible display by changing the frame rate or resolution. In this regard, Patent Document 1 does not consider flexibly changing the frame rate and resolution.

  The present invention has been made in view of the above problems, and a purpose thereof is a technique capable of changing a display mode of an image displayed on a projection surface by laser scanning in accordance with characteristics of display data projected on the projection surface. Is to provide.

  In order to solve this problem, for example, the projection apparatus of the present invention has the following configuration. That is, input means for inputting an image signal, setting means for setting the resolution of an image to be displayed on the projection plane, light source means for outputting a laser beam modulated in accordance with the image signal, and on the projection plane Control means for controlling the emission direction of the laser beam so that the laser beam scans in a first direction at a predetermined frequency and in a second direction at a frequency according to the set resolution; And when the resolution in the second direction of the set resolution is the first resolution, the control means scans the laser beam in the second direction at a first frequency, and sets the set When the resolution in the second direction of the resolution is a second resolution higher than the first resolution, the emission direction is caused to scan the laser light in the second direction at a second frequency lower than the first frequency. Control To, characterized in that.

  According to the present invention, it is possible to change the display mode of an image displayed on a projection surface by laser scanning in accordance with the characteristics of display data projected onto the projection surface.

1 is a block diagram illustrating an example of a functional configuration of a projector according to a first embodiment. FIG. 6 is a diagram for explaining display timing in the main scanning direction according to the first embodiment. FIG. 5 is a diagram illustrating an example of a sub-scanning drive signal according to the first embodiment. The figure for demonstrating the example of the display resolution and display frame rate which are determined according to the data for display based on Embodiment 1. FIG. FIG. 6 is a block diagram illustrating an example of a functional configuration of a projector according to a second embodiment. The figure for demonstrating the example of the display resolution and display frame rate which are determined according to the data for display based on Embodiment 2. FIG.

(Embodiment 1)
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, an example in which a projector capable of two-dimensionally scanning laser light will be described as an example of a projection apparatus. However, the present embodiment is not limited to a projector, and can be applied to other devices that can project display data by scanning laser light two-dimensionally. These devices may include, for example, game machines, medical devices, digital signage devices, in-vehicle devices, and the like.

(Projector configuration)
FIG. 1 is a block diagram illustrating a functional configuration example of a projector as an example of a projection apparatus according to the present embodiment. Note that one or more of the functional blocks illustrated in FIG. 1 may be realized by hardware such as an ASIC or a programmable logic array (PLA), or may be realized by executing software by a programmable processor such as a CPU or GPU. May be. Further, it may be realized by a combination of software and hardware. Therefore, in the following description, even when different functional blocks are described as the operation subject, the same hardware can be realized as the subject.

  The control unit 101 includes an arithmetic device such as a CPU (or MPU, GPU), for example, and controls each operation block of the projector 100 by developing and executing a program stored in the ROM 102 in the RAM 117. Note that the control unit 101 may also have functions of a signal processing unit 105 and a laser control unit 106, which will be described later, and in this case, executes processing of the signal processing unit 105 and the laser control unit 106.

  The ROM 102 includes a nonvolatile memory such as a semiconductor memory, and stores characteristics necessary for generating a waveform pattern and a drive current by a laser control unit 106 to be described later, design information on the resonance frequency of the scanning mirror 114, and the like. The RAM 117 includes a volatile memory such as a DRAM, and temporarily stores variables when the control unit 101 executes a program. The RAM 117 may function as a frame memory that temporarily stores a part of data when another block such as the signal processing unit 105 processes an image signal.

  The image signal input unit 103 inputs an image signal (display data) to be projected onto the projection plane 200 and outputs the display data to the display format determination unit 104 and the signal processing unit 105 described later. The display data includes still image and video data such as data in JPEG format or MPEG format, for example. 1 shows a connection configuration in which display data is input from the outside of the projector 100, the display data read from the RAM 117 inside the projector 100 or a detachable recording medium (not shown). May be input.

  The operation unit 118 includes operation members such as buttons and a touch panel, detects an operation by the user, and notifies the control unit 101 of the operation content. The user can set or change a desired setting value or the like via the operation unit 118 while visually checking an operation menu displayed on the projection surface or the touch panel in accordance with an instruction from the control unit 101.

  The display format determination unit 104 determines the display data based on the analysis result of the video synchronization signal included in the display data input to the image signal input unit 103 or various metadata included in the display data, for example, the header. Determine the display resolution. In addition to those exemplified in this embodiment, the resolution includes, for example, 2K DCI (2048 × 1080), 4K UHDTV (3840 × 2160), 4K DCI (4096 × 2160), 8K UHDTV (7680 × 4320), and the like. It's okay. In the present embodiment, the number of horizontal and vertical pixels in a screen created by pixels that are dot-drawn on the projection surface by scanning with a scanning mirror 114, which will be described later, is collectively referred to as display resolution. At this time, the display resolution is expressed as “the number of horizontal pixels × the number of vertical pixels”. In the following description, an example will be described in which the display format determination unit 104 analyzes and acquires the number of pixels of input display data, and determines the acquired number of pixels as the display resolution for the display data.

Further, the display format determination unit 104 determines a display frame rate for displaying the display data based on the above-described display resolution and a resonance frequency of a scanning mirror 114 described later. Specifically, the display frame rate can be calculated according to Equation (1) using the vertical display resolution and the resonance frequency of the scanning mirror 114.

Display frame rate = resonance frequency / (vertical display resolution / 2) (1)

  The signal processing unit 105 temporarily writes the display data output from the image signal input unit 103 into the RAM 117 or a frame memory (not shown), buffers it, generates a predetermined dot clock, and reads the display data from the frame memory. . The signal processing unit 105 includes a timing adjustment unit 105a, and the timing adjustment unit 105a generates a dot clock. Details of the processing for generating the dot clock will be described later. The signal processing unit 105 outputs the read display data to the laser control unit 106 described later.

  Based on the display data output from the image signal input unit 103, the laser control unit 106 determines a laser driving current level for displaying each pixel and a laser driving waveform pattern applied to each pixel. The laser control unit 106 outputs the determined laser driving current level and the laser driving waveform pattern applied to each pixel to the laser driver 107.

  The laser driver 107 modulates the drive current for each color component of each pixel using the laser drive waveform pattern output from the laser control unit 106, and outputs the modulated drive current to laser light sources 108 to 110 described later.

  The laser light sources 108, 109, and 110 emit laser light with a modulated driving current supplied from the laser driver 107. A red component (R) is emitted from the laser light source 108, a green component (G) is emitted from the laser light source 109, and a blue component (B) is emitted from the laser light source 110 at an output level corresponding to the gradation to be displayed. In this embodiment, the case of direct modulation in which laser light is emitted by a drive current modulated in accordance with the signal value of the pixel will be described as an example. However, external modulation that modulates emitted laser light may be employed. .

  The dichroic mirrors 111 and 112 synthesize only the laser light of each color component emitted from the laser light sources 108 to 110 by transmitting only the laser light having a specific wavelength and reflecting the other wavelength light. The green and blue component laser beams emitted from the laser light sources 109 and 110 are combined by the dichroic mirror 112. Further, the combined laser beam is combined with the red component laser beam emitted from the laser light source 108 in the dichroic mirror 111 to become a laser beam including RGB three primary color components. The lens 113 includes a condensing lens for collecting the laser light from the dichroic mirror 111.

  The scanning mirror 114 is a MEMS device manufactured by applying a semiconductor integrated circuit processing technique, and reflects the laser light incident from the lens 113 and projects it onto the projection plane 200. The scanning mirror 114 can be driven biaxially so as to deflect light in the main scanning direction (for example, the horizontal direction of the image) and the sub-scanning direction (for example, the vertical direction of the image). For example, the scanning mirror 114 supplies current to a coil provided in the mirror and generates a magnetic force in a direction perpendicular to the coil, so that the mirror is resonantly driven (at a resonance point) at a vibration frequency unique to the main scanning direction. Reciprocating).

  In order to realize a MEMS device that drives a mirror at high speed, the mirror must be driven to resonate. As described above, a signal format to be displayed is assumed, and the characteristics of the MEMS device are designed according to the format. Need to make. For example, a signal with a signal format of 1080p (effective display resolution: 1920 × 1080, frame rate: 60 Hz) is assumed as a standard image signal assumed for display by the projector 100. Here, the total display resolution in consideration of the scanning blanking time (blanking period) in the signal format is 2200 × 1125. In order to be able to display such a 1080p format signal, the scanning mirror 114 needs to resonate at a frequency capable of scanning 1125 lines in 1/60 seconds (one frame period).

  When the laser beam scans from the left to the right and from the right to the left of the projection surface 200, assuming that pixels are drawn in each scanning (that is, reciprocation), the scanning mirror 114 has 1125 lines × 60 Hz / 2 = Resonates at a resonance frequency of 33.75 kHz. As described above, since the mirror is driven in the main scanning direction (for example, the horizontal direction of the display data) at a high speed operation of several tens kHz as described above, it is necessary to perform the resonance driving. That is, it is assumed that the scanning mirror 114 is always driven at a constant frequency (resonance frequency unique to MEMS) in the main scanning direction. On the other hand, the driving of the mirror in the sub-scanning direction (for example, the vertical direction of the display data) can be performed non-resonant because it operates at a low speed of several tens of Hz depending on the frame rate. That is, the scanning mirror 114 is driven with a variable frequency in the sub-scanning direction. The mirror control in the main scanning direction and the sub scanning direction will be described in detail later.

  The scanning mirror vibration detection unit 115 includes, for example, an amplifier circuit and a filter, and detects the resonance drive frequency of the scanning mirror 114 in the main scanning direction. For example, a vibration detection signal in a resonance-driven state is detected from a detection piezoelectric element provided in the MEMS device of the scanning mirror 114. In the present embodiment, the configuration in which the scanning mirror vibration detection unit 115 dynamically detects the vibration period of the scanning mirror 114 is described as an example. However, the present invention is not limited to this, and for example, the design value of the resonance frequency stored in advance in the ROM 102 A configuration using information may also be used.

  The scanning mirror control unit 116 is, for example, a control circuit that controls the scanning mirror 114 so that laser light incident on the scanning mirror 114 draws a predetermined image area. And a control unit 116b. In the following description, the scanning mirror control unit 116 is described as a configuration including the main scanning control unit 116a and the sub-scanning control unit 116b separately, but the configuration may not be separate. The control unit 101 may also have the function of the scanning mirror control unit 116.

  The main scanning control unit 116a adjusts the phase of the vibration detection signal detected by the scanning mirror vibration detection unit 115 so that the scanning mirror resonates in the main scanning direction. Then, the main scanning drive signal after adjusting the phase is applied to the driving piezoelectric element provided in the scanning mirror 114. As a result, the scanning mirror 114 is driven to resonate in the main scanning direction. Further, as described above, the sub-scan control unit 116b non-resonantly drives the scanning mirror 114 in the sub-scanning direction in accordance with the vertical period of the display data. Specifically, the sub-scanning control unit 116b acquires the display frame rate determined by the display format determining unit 104. Then, the sub-scanning drive signal is output to the scanning mirror 114 while matching the timing with the main scanning drive signal output from the main scanning control unit 116a. Here, the sub-scanning drive signal is a signal for swinging the scanning mirror 114 in the sub-scanning direction at the acquired display frame rate.

(Operation related to image drawing)
Next, an operation related to image drawing according to the present embodiment will be described. First, the operation of the main scanning control unit 116a will be described with reference to FIG. FIG. 2 shows an example of the display timing of display data based on scanning mirror control in the main scanning direction. FIG. 2A shows an example of a vibration detection signal detected by the scanning mirror vibration detection unit 115. The timing adjustment unit 105a of the signal processing unit 105 calculates a vibration frequency in the main scanning direction based on the vibration detection signal 201 of FIG. 2A detected by the scanning mirror vibration detection unit 115 (that is, 33.75 kHz). sine wave). Then, a dot clock is generated based on the vibration frequency and the horizontal display resolution determined by the display format determination unit 104.

FIG. 2B shows an example of a dot clock generated by the timing adjustment unit 105a when the above-described 1080p video signal is input. Each clock of the dot clock is used to form one pixel (in the main scanning direction) for each clock. In a 1080p video signal, 2,200 × 2 = 4,400 dot clocks are required in one cycle in the main scanning direction. Therefore, a dot clock DCLK is generated by multiplying the resonance frequency (vibration frequency in the main scanning direction) of the scanning mirror 114 by 4,400. That is, the frequency of the dot clock is as shown in equations (2) and (3).

DCLK = 33.75 kHz × 4,400 (2)
= 148.5 MHz (3)

In accordance with the timing of the dot clock generated in this way, the signal processing unit 105 reads display data from the frame memory and outputs the display data to the laser control unit 106, whereby each line is displayed at a predetermined horizontal display resolution. Is drawn. Note that each clock shown in FIG. 2B is enlarged and displayed for visibility, and therefore does not strictly correspond to the display timing of each pixel shown in FIG.

  Further, FIG. 2C shows a clock for controlling each timing of the effective pixel region and the blanking region. The laser light sources 108 to 110 emit laser light according to a dot clock while the clock shown in FIG. 2C is rising, and draw pixels in the effective pixel region. FIG. 2D schematically shows a case where 1920 pixels are drawn in the horizontal direction in the effective pixel region.

  Next, the operation of the sub-scanning control unit 116b will be described. FIG. 3 shows an example of the sub-scanning drive signal. As shown on the left side of FIG. 3, the sub-scanning drive signal 301 is a triangular wave, and controls the vertical angle of the scanning mirror over a period of one frame at the display frame rate. This sub-scanning drive signal is a relatively slow swing enough to secure a time for drawing a main scanning line for one screen.

  In this way, the scanning mirror control unit 116 emits the scanning mirror so as to scan the laser light in the sub-scanning direction at a frequency determined according to the vertical display resolution while scanning in the main scanning direction at the resonance frequency. The angle (that is, the laser beam emission direction) is controlled.

  Next, with reference to FIG. 4, an operation example for determining the display resolution and the display frame rate according to the display data input to the projector 100 will be described. As described above, the MEMS device used in the scanning mirror 114 of the projector 100 according to the present embodiment is configured to resonate at a resonance frequency (= 33.75 kHz) assuming a signal format of 1080p. .

  FIG. 4A illustrates an example of parameters determined when display data having a 1080p signal format is input to the image signal input unit 103.

  First, the display format determination unit 104 determines the display resolution of the display data as the display resolution of the projector 100. For this reason, the horizontal display resolution is determined as 2,200, and the vertical display resolution is determined as 1,125. The display format determination unit 104 determines the display frame rate as 60 Hz using the vertical display resolution and the resonance frequency based on the above-described equation (1). Further, the signal processing unit 105 determines the dot clock for realizing the determined display resolution as 148.5 MHz based on the horizontal display resolution and the resonance frequency according to the above-described equations (2) and (3).

  On the other hand, FIG. 4B shows an example of parameters determined when display data having a total display resolution of 4,400 × 2,400 including a blanking period is input to the image signal input unit 103. Show. In the example shown in FIG. 4B, first, the display format determination unit 104 determines the display resolution of the display data as the display resolution of the projector 100, as in the case of FIG. Therefore, the horizontal display resolution is determined as 4,400, and the vertical display resolution is determined as 2,400. Further, the display format determination unit 104 determines the display frame rate as 28.125 Hz based on the above equation (1). At this time, since the display data according to FIG. 4B has a higher vertical display resolution than the display data according to FIG. 4A, the frame rate of the display data according to FIG. The value is determined to be lower than the frame rate of 4 (a). That is, the frequency of scanning in the vertical direction when displaying the display data according to FIG. 4B is smaller than the frequency of scanning in the vertical direction when displaying the display data according to FIG. As determined.

  Furthermore, the signal processing unit 105 determines the dot clock for realizing the determined display resolution as 297 MHz based on the horizontal display resolution and the resonance frequency in accordance with the above-described equations (2) and (3). That is, the dot clock for the display data according to FIG. 4B is determined to have a higher value because the horizontal display resolution is higher than that of the display data according to FIG.

  In this way, even when the input display data has a resolution exceeding the assumed format preset in the MEMS device, the display frame rate is reduced compared with the assumed format, and the scanning mirror is used. The vertical drive 114 is controlled. In this way, the scanning mirror 114 can handle display data with a vertical display resolution that exceeds the assumed format while using resonance vibration.

  In the above-described embodiment, the operation of determining the resolution of the input video as the display resolution has been described as an example. However, the determination of the display resolution is not limited to this. Specifically, the operation may be an operation in which the user sets a desired resolution in advance using the operation unit 118 and determines the set resolution as the display resolution of the projector 100. The user can select one of two or more display modes including a display mode for determining the display resolution and frame rate based on the resolution of the input video and a display mode for displaying an image at a preset display resolution and frame rate. It may be selectable. In this case, the projector 100 displays an image based on the selected display mode. When the display mode that determines the display resolution and the frame rate based on the resolution of the input video is selected, the projector 100 sets the display resolution and the frame rate and displays the image as shown in the above-described embodiment. . That is, when the resolution of the input video exceeds the assumed format preset in the MEMS device, the vertical drive of the scanning mirror 114 is controlled by reducing the display frame rate as compared with the assumed format. . On the other hand, when a display mode for displaying an image at a preset display resolution and frame rate is selected, the projector 100 has a resolution and a frame rate so that the image can be displayed at the set display resolution and frame rate. An image is displayed based on the converted input video.

  Furthermore, the display resolution can be set by the user, and the image can be displayed at a frame rate corresponding to the set display resolution. For example, when the user sets the display resolution to 2K (1920 × 1080) resolution, the projector 100 displays an image with a frame rate of 60 Hz as in the above-described embodiment. When the user sets the display resolution to the resolution of 4K UHDTV (3840 × 2160), the projector 100 displays an image with a frame rate lower than 60 Hz (30 Hz). That is, the user selects one of a plurality of display modes having different display resolutions and frame rates, and the projector 100 displays an image based on the display resolution and the frame rate of the selected display mode.

  Further, the projector 100 may include a video signal analysis unit (not shown) that determines whether or not the input image is a still image based on the image content and metadata of the input video data. In this case, for example, the frame rate can be determined based on the display resolution and the resonance frequency only when it is determined that the display data is a still image. In addition, when a moving image having a higher resolution than the assumed format is input, it is possible to prevent the display frame rate from being lowered than the original frame rate of the moving image. On the other hand, when it is determined that the display data is a moving image, a predetermined frame rate for the display data may be used.

  As described above, in this embodiment, the display resolution can be improved by dynamically changing the display frame rate of the laser scanning projector using resonance according to the display resolution. In this way, display resolution can be improved instead of sacrificing the frame rate for display data with low necessity for moving image visibility such as still image display. That is, the display mode of the image displayed on the projection surface by laser scanning can be changed in accordance with the characteristics of the display data projected on the projection surface.

(Embodiment 2)
Next, Embodiment 2 will be described. In the first embodiment, the display frame rate is changed according to the display resolution. However, as understood from the above equation (1), the higher the display resolution, the lower the display frame rate. Therefore, if the display resolution is increased to a certain extent, flicker occurs as the display frame rate decreases. May increase and display quality may deteriorate. Therefore, in the second embodiment, an operation example in which the display resolution is improved by using both scanning mirror control and image processing so as not to fall below a predetermined display frame rate determined in advance will be described. Note that the configuration of the projector according to the second embodiment is the same as that of the first embodiment except for the configuration of the display format determination unit and the signal processing unit. For this reason, the same reference numerals are assigned to the same components, and redundant descriptions are omitted, and differences will be mainly described.

  FIG. 5 shows a functional configuration example of the projector 500 according to the present embodiment. The display format determination unit 501 calculates the frame rate based on the display resolution and the resonance frequency of the scanning mirror 114 according to the equation (1), similarly to the display format determination unit 104 in the first embodiment.

  Also, the display format determination unit 501 determines the magnitude relationship between the calculated frame rate and a predetermined frame rate that is set in advance. When it is determined that the calculated frame rate is lower than the predetermined frame rate, the predetermined frame rate is determined as the display frame rate of the projector 500 instead of the calculated frame rate. On the other hand, when it is determined that the calculated frame rate is equal to or higher than the predetermined frame rate, the calculated frame rate is determined as the display frame rate.

  Further, the display format determination unit 501 calculates a target resolution for displaying the display data on the projector 500 based on the determined display frame rate and the resonance frequency of the scanning mirror 114. A specific example of the operation for calculating the target resolution will be described later.

  Similar to the signal processing unit 105 according to the first embodiment, the signal processing unit 502 once writes video data in the frame memory and buffers it, then generates a dot clock, and reads display data from the frame memory. Further, the signal processing unit 502 calculates a magnification for scaling the display data based on the target resolution calculated by the display format determining unit 501. Then, the display data is scaled (reduced) by image processing according to the calculated magnification. A specific example of the operation for calculating the magnification will be described later. Note that the signal processing unit 502 includes a timing adjustment unit 105a as in the first embodiment.

  Next, a specific example of the operation for calculating the display resolution (target resolution) and the display frame rate according to the present embodiment will be described with reference to FIG. Note that the MEMS device used in the scanning mirror 114 of the projector 500 according to the present embodiment is configured to resonate at a resonance frequency (= 33.75 kHz) assuming a 1080p format, as in the first embodiment. .

  As described above, the display format determination unit 501 determines the display frame rate after determining the magnitude relationship between the calculated frame rate and a predetermined frame rate set in advance separately. The predetermined frame rate used at this time is set in advance to 20 Hz, for example. The threshold value of 20 Hz is set by an experiment or the like conducted in advance, assuming that the display quality deteriorates due to an increase in flicker or the like at a frame rate below this threshold value.

  FIG. 6A illustrates the case where display data having a total display resolution of 2,400 × 4,400 including a blanking period is input to the image signal input unit 103 by the projector 100 according to the first embodiment. An example in which the display frame rate is determined is shown. That is, FIG. 6A shows an example in which determination of the magnitude relationship with a predetermined frame rate is not considered.

  Specifically, first, the display format determination unit 104 determines the horizontal display resolution as 2,400 and the vertical display resolution as 4,400 based on the input display data. Then, the display format determining unit 104 determines the display frame rate for realizing the determined display resolution to be 15.341 Hz. Further, the signal processing unit 105 determines the dot clock for realizing the determined display resolution to 162 MHz based on the horizontal display resolution and the resonance frequency in accordance with the above formulas (2) and (3).

  On the other hand, FIG. 6B shows a display frame rate determined by the projector 500 according to the present embodiment when display data having a total display resolution including a blanking period of 2,400 × 4,400 is input. An example is shown. That is, FIG. 6B shows an example in which determination of the magnitude relationship with a predetermined frame rate is considered.

  In the example shown in FIG. 6B, first, the display format determination unit 104 determines the horizontal display resolution as 4,400 and the vertical display resolution as 2,400. Then, as described above, the display format determination unit 104 calculates the display frame rate for realizing the determined display resolution as 15.341 Hz. The calculated display frame rate is equal to or lower than a predetermined frame rate (the predetermined frame rate is 20 Hz). In this case, the display format determination unit 104 determines a predetermined frame rate larger than the calculated frame rate as the display frame rate, not the calculated frame rate of 15.341 Hz.

Then, the display format determination unit 104 calculates the vertical display resolution when the display frame rate is 20 Hz as follows.

Vertical display resolution = 2 × (resonance frequency / display frame rate) (4)
= 2 x (33.75 kHz / 20 Hz)
= 3,375

  In this way, the vertical display resolution (= total number of one screen of the main scanning line) is calculated as 3,375, but the vertical resolution of the input display data is 4,400. Therefore, the signal processing unit 502 performs a scaling process on the input video data at a magnification of 3,375 / 4, 400≈0.767, so that the display in accordance with the display resolution determined by Expression (4) is performed. Data is generated. That is, when the calculated display frame rate is equal to or lower than a predetermined frequency, the display data is reduced so that the vertical display resolution is equal to or lower than the calculated vertical resolution.

  For the reduction processing by the signal processing unit 502, a known method such as pixel thinning or line thinning can be used. At this time, the signal processing unit 502 reduces the display data while maintaining the aspect ratio. Therefore, the horizontal display resolution can be determined based on the aspect ratio and vertical resolution of the display data. Further, the signal processing unit 502 may generate the dot clock and read out from the frame memory so that the scaling process is also performed in the horizontal direction at a magnification in accordance with the vertical display resolution.

  In the above-described processing, the magnitude relationship between the frame rate obtained from the display data and the predetermined frame rate is compared. However, similar processing can be realized by comparing the resolution of the display data with a predetermined resolution as described below. That is, the display format determination unit 104 corresponds the vertical display resolution to the predetermined frame rate when the vertical resolution of the display data is equal to or higher than the predetermined resolution associated with the predetermined frame rate. Set the given resolution. Further, when the vertical resolution of the display data is lower than the resolution for ensuring a predetermined frame rate, the vertical display resolution is set to the vertical resolution of the display data. Therefore, when the vertical resolution of the display data is equal to or higher than the resolution for ensuring a predetermined frame rate, the scanning mirror control unit 116 scales the display data and then performs the predetermined frame rate. Display the display data with. Otherwise, the display data is displayed at a frame rate higher than the predetermined frame rate and obtained from the display data at the time of input.

  As described above, according to the present embodiment, the frame rate is determined so as not to fall below a predetermined display frame rate determined in advance, and when the predetermined frame rate is used, the display image is scaled and displayed. Improved the resolution. By doing in this way, it can prevent that the display quality of the content displayed on the projection surface falls by the increase in flicker etc.

(Other embodiments)
In the above-described embodiment, the example in which the laser beam emission direction is controlled by reflecting the laser beam with the mirror of the MEMS device that vibrates at the resonance frequency has been described. However, the control of the laser beam emission direction is not limited to reflection by a mirror, and any other laser beam emission direction may be controlled based on a predetermined frequency (such as a resonance frequency) with respect to a certain direction. This method may be used.

  The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in the computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

DESCRIPTION OF SYMBOLS 101 ... Control part, 104 ... Display format determination part, 108, 109, 110 ... Light source, 114 ... Scanning mirror, 116 ... Scanning mirror control part

Claims (20)

An input means for inputting an image signal;
Setting means for setting the resolution of the image to be displayed on the projection plane;
Light source means for outputting laser light modulated in accordance with the image signal;
On the projection plane, the laser beam emission direction is controlled so that the laser beam scans in the first direction at a predetermined frequency and in the second direction at a frequency according to the set resolution. Control means to
With
The control means includes
When the resolution in the second direction of the set resolution is the first resolution, the laser beam is scanned in the second direction at a first frequency,
When the resolution in the second direction of the set resolution is a second resolution higher than the first resolution, the laser beam is scanned in the second direction at a second frequency lower than the first frequency. The projection direction is controlled as described above. The control means includes
When the resolution in the second direction of the set resolution is equal to or higher than a predetermined resolution, the laser beam is scanned in the second direction at a frequency associated with the predetermined resolution,
When the resolution in the second direction of the set resolution is lower than the predetermined resolution, the laser beam is scanned in the second direction at a frequency higher than the frequency associated with the predetermined resolution. The projection apparatus according to claim 1, wherein the emission direction is controlled so as to cause the emission to occur.   The control means determines a frequency for scanning the laser beam in the second direction based on the resolution in the second direction of the set resolution and the predetermined frequency. The projection apparatus according to claim 1 or 2.   When the frequency at which the laser beam is scanned in the second direction is equal to or lower than a predetermined threshold, the resolution of the image displayed on the projection plane is equal to or lower than the resolution of the set resolution in the second direction. The projection apparatus according to claim 3, further comprising a scaling unit that reduces the image signal.   When the image signal is a moving image, the control means controls the emission direction by setting a frequency for scanning the laser light in the second direction as a frequency set in advance for the image signal. The projection apparatus according to any one of claims 1 to 4, wherein the projection apparatus is characterized in that: A scanning mirror that reflects the laser beam;
The control means controls the emission direction of the laser light by controlling the angle of the scanning mirror,
The predetermined frequency is a resonance frequency of the scanning mirror,
The control means scans the laser beam in the first direction at the resonance frequency and scans in the second direction at a frequency corresponding to the resolution in the second direction of the set resolution. The projection apparatus according to claim 1, wherein an angle of the scanning mirror is controlled.   Generation for generating a clock for drawing pixels constituting the image to be displayed on the projection plane based on the resolution in the first direction of the set resolution and the resonance frequency of the scanning mirror The projection apparatus according to claim 6, further comprising means.   The frequency according to the resolution in the second direction of the set resolution is a frame rate when the projection apparatus displays an image on the projection plane. The projection device according to claim 1. A projection device for displaying an image on a projection surface,
An input means for inputting an image signal;
Light source means for outputting laser light modulated based on the image signal;
Control means for controlling an emission angle of the laser light so that the laser light is scanned in the first direction and the second direction on the projection surface;
Setting means for setting any one of two or more display modes having different resolutions of the image displayed on the projection plane;
With
The control means includes
When the setting unit sets a first display mode in which the image is displayed at the first resolution, the laser light scans on the projection surface at a predetermined frequency in the first direction, and the second direction. To control the emission angle of the laser beam so as to scan at the first frame rate,
When the setting means sets a second display mode for displaying the image at a second resolution higher than the first resolution, the laser beam is scanned at the predetermined frequency in the first direction, and The projection apparatus, wherein the laser beam emission angle is controlled to scan in a second direction at a second frame rate lower than the first frame rate. The setting means includes
Determining the resolution of the image displayed on the projection plane based on the image signal;
The projection apparatus according to claim 9, wherein a display mode corresponding to the determined resolution is set out of the two or more display modes.   The projection apparatus according to claim 9, wherein the setting unit sets any one of the two or more display modes in accordance with a user instruction. A method for controlling a projection apparatus including a light source that outputs laser light,
An input process for inputting an image signal;
A setting step for setting the resolution of the image to be displayed on the projection plane;
An output step in which the light source outputs laser light modulated in accordance with the image signal;
On the projection plane, the laser beam emission direction is controlled so that the laser beam scans in the first direction at a predetermined frequency and in the second direction at a frequency according to the set resolution. A control process,
Have
In the control step,
When the resolution in the second direction of the set resolution is the first resolution, the laser beam is scanned in the second direction at a first frequency,
When the resolution in the second direction of the set resolution is a second resolution higher than the first resolution, the laser beam is scanned in the second direction at a second frequency lower than the first frequency. The projection direction is controlled as described above. In the control step,
When the resolution in the second direction of the set resolution is equal to or higher than a predetermined resolution, the laser beam is scanned in the second direction at a frequency associated with the predetermined resolution,
When the resolution in the second direction of the set resolution is lower than the predetermined resolution, the laser beam is scanned in the second direction at a frequency higher than the frequency associated with the predetermined resolution. The method of controlling a projection apparatus according to claim 12, wherein the emission direction is controlled so that   In the control step, a frequency for scanning the laser light in the second direction is determined based on the resolution in the second direction of the set resolution and the predetermined frequency. A method for controlling a projection apparatus according to claim 12 or 13. When the frequency at which the laser beam is scanned in the second direction is equal to or lower than a predetermined threshold, the resolution of the image displayed on the projection plane is equal to or lower than the resolution of the set resolution in the second direction. The projection apparatus according to claim 14, further comprising a scaling step for reducing the image signal.
Control method.   In the control step, when the image signal is a moving image, the frequency of scanning the laser light in the second direction is set as a frequency preset for the image signal, and the emission direction is controlled. The method for controlling a projection apparatus according to claim 12, wherein: The projection apparatus further includes a scanning mirror that reflects the laser light,
In the control step, by controlling the angle of the scanning mirror, the emission direction of the laser beam is controlled,
The predetermined frequency is a resonance frequency of the scanning mirror,
In the control step, the laser beam is scanned in the first direction at the resonance frequency, and is scanned in the second direction at a frequency according to the resolution in the second direction of the set resolution. The method of controlling a projection apparatus according to any one of claims 12 to 16, wherein an angle of the scanning mirror is controlled. A control method for a projection apparatus that includes a light source that outputs laser light and displays an image on a projection surface,
An input process for inputting an image signal;
An output step in which the light source outputs a laser beam modulated based on the image signal;
A setting step of setting any one of two or more display modes having different resolutions of the image displayed on the projection plane;
A control step of controlling an emission angle of the laser light so that the laser light is scanned in the first direction and the second direction on the projection surface;
Have
In the control step,
When the first display mode for displaying the image at the first resolution is set in the setting step, the laser light scans on the projection surface at a predetermined frequency in the first direction, and the second Controlling the emission angle of the laser beam to scan in the direction at the first frame rate;
When the second display mode for displaying the image at a second resolution higher than the first resolution is set in the setting step, the laser beam is scanned at the predetermined frequency in the first direction, and A projection apparatus control method, wherein the laser beam emission angle is controlled to scan in the second direction at a second frame rate lower than the first frame rate.   19. The method for controlling a projection apparatus according to claim 18, wherein in the setting step, one of the two or more display modes is set in accordance with a user instruction.   The program for functioning a computer as each means of the projection apparatus of any one of Claim 1 to 11.

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