JP2021111880A - Image projection device and program - Google Patents

Abstract

To provide an image projection device capable of improving a sense of resolution and moving image visibility by displaying according to a state of shift operation.SOLUTION: An image projection device (100) has a light source unit (62), an image display element (66), control means (30) capable of controlling the light intensity of pixels projected on a surface to be projected, and shift means (67) for shifting pixels in synchronization with a cycle of subframes for forming one frame of an input image. The control means is configured to change the light intensity based on the state of a shift operation by the shift means.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image projection device that performs pixel shifting.

Conventionally, in a projector (image projection device) equipped with a light modulation element such as a liquid crystal light valve, the display resolution of the projected image (total number of pixels visible on the projected surface) is determined by the number of pixels of the light modulation element. .. Therefore, in order to improve the display resolution, it is necessary to increase the number of pixels of the light modulation element, which increases the cost.

In Patent Document 1, a flat plate prism is inserted between the light modulation element and the projection lens at an angle with respect to the optical axis slope to perform a parallel shift of the optical axis, and the image signal displayed on the light modulation element is obtained. A method of improving the display resolution by changing the shift amount in synchronization is disclosed. According to the method disclosed in Patent Document 1, for example, the display image is decomposed into four images by controlling the shift in four directions during one frame period, and the display image is displayed on the light modulation element in conjunction with the shift operation. This makes it possible to obtain four times the display resolution.

JP-A-11-298829

However, in the method disclosed in Patent Document 1, the pixel display is performed at a position different from the originally desired position during the period of the process of shifting the pixel position from the current position to the target position. Therefore, if the period required for the shift is longer than the period for displaying the pixels, one pixel is displayed as a blur, and the resolution and the visibility of the moving image are deteriorated.

Therefore, an object of the present invention is to provide an image projection device and a program capable of improving resolution and moving image visibility by displaying pixels according to the state of shift operation.

The image projection device as one aspect of the present invention includes a light source unit, an image display element, a control means capable of controlling the amount of light of pixels projected on the projected surface, and a sub for forming one frame of an input image. It has a shift means for shifting the pixel in synchronization with the period of the frame, and the control means changes the amount of light based on the state of the shift operation by the shift means.

The program as one aspect of the present invention includes a step of acquiring a state of a shift operation by a shift means for shifting pixels in synchronization with a period of a subframe for forming one frame of an input image, and a state of the shift operation. The computer is made to perform a step of changing the amount of light of the pixel based on the above.

Other objects and features of the present invention will be described in the following examples.

According to the present invention, it is possible to provide an image projection device and a program capable of improving resolution and moving image visibility by displaying pixels according to the state of shift operation.

It is a block diagram of the projector in each embodiment. It is a flowchart of the control method in Example 1. FIG. It is a figure which shows an example of the position information acquired from the encoder of the shift means in each embodiment. It is a flowchart of the control method in Example 2. It is a figure which shows the image drawn on the light modulation element in conjunction with the shift operation in each Example.

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

First, the projector (image projection device) 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of the projector 100.

The image processing unit 10 includes a terminal for inputting an input image signal from a composite terminal, an HDMI (registered trademark) terminal, a DVI terminal, a Displayport terminal, or the like. Further, it is provided with devices such as an AD converter and a receiver IC necessary for receiving the input image signal input through those terminals. Further, the image processing unit 10 is provided with a USB terminal and a LAN terminal, and can receive JPEG, BMP, and PNG image files and streaming moving images as input image signals.

Further, the image processing unit 10 can perform image processing on an image based on the input image signal. That is, the image processing unit 10 performs arbitrary image processing from among brightness adjustment and contrast adjustment, color conversion by LUT, resolution conversion to an arbitrary resolution, sharpening processing and smoothing processing, frame rate conversion, IP conversion, and the like. Generates the image signal. Further, the image processing unit 10 performs statistical analysis of the input image signal to acquire information on the luminance distribution and frequency components of each frame, and performs measurement over a plurality of frames to obtain information on the difference between frames and the amount of motion. Can be obtained. The acquisition of information may be either local information or information as a whole image. When the information is the amount of movement, a numerical value representing the vector or the magnitude of the movement itself can be obtained, and in the case of a frequency component, a normalized numerical value can be obtained in the form of the frequency of each component.

The OSD superimposition unit (operation display unit) 20 superimposes the OSD image on the image signal output from the image processing unit 10. The OSD image can be generated based not only on image data such as a bitmap prepared in advance, but also on a straight line, a rectangle, or a drawing instruction for each pixel. The geometric distortion correction unit 40 performs deformation processing on the image signal output from the OSD superimposition unit 20 so as to independently correct the geometric distortion generated in the projected image for each color. If the geometric distortion correction unit 40 performs appropriate conversion, it is possible to suppress distortion of the projected image caused by tilt projection, curvature of the projection surface, aberration of the lens, and the like.

The display drive unit 50 is connected to the geometric distortion correction unit 40, converts the image signal corrected by the geometric distortion correction unit 40 into a display drive signal, and drives the light modulation element (image display element) 66 of the optical system 60. .. Further, the display drive unit 50 adjusts the brightness on a pixel-by-pixel basis, adjusts the position where an image is formed on the light modulation element, and makes the superimposed portion inconspicuous when performing multi-projection. It is possible to perform gradation correction for each of the region and the non-blend region. The drive signal for driving the light modulation element 66 is a signal linked with the shift means (pixel shift unit) 67 described later, and is a subframe (for example, (b) to (e) in FIG. 5) divided in time for one frame. )) Are output with different drive signals. FIG. 5 is a diagram showing an image drawn on the light modulation element 66 in conjunction with the shift operation. For example, by controlling the shift in four directions during one frame period, the display image (input image or frame) shown in FIG. 5 (a) is displayed in FIGS. 5 (b), (c), (d), (e). ) Is decomposed into four images (subframed to increase the resolution). Then, by displaying the image on the light modulation element 66 in conjunction with the shift operation (that is, shifting the pixels in synchronization with the period of the subframe for forming one frame of the input image), a four-fold display resolution can be obtained. Be done.

The CPU unit 30 drives the light modulation element 66 while performing pixel shift based on the drive signal by the display drive unit 50, thereby realizing a display resolution exceeding the number of pixels of the light modulation element 66. Further, the display drive unit 50 can further divide the subframe into a plurality of fields and output the subframe, and can adjust the brightness for each field. Here, the field refers to an image group corresponding to a color period constituting one projection image in a system for displaying in a color sequential format using a color wheel or the like.

The optical system 60 includes a light source unit 62, an illumination optical system 64, a light modulation element (image display element) 66, a shift means (pixel shift unit) 67, and a projection optical system 68. The light emitted from the light source unit 62 passes through the illumination optical system 64, is modulated by the light modulation element 66, and then passes through the projection optical system (projection lens) 68 through the projection optical system (projection lens) 68 to form a screen (projected surface). ) Is projected. The light modulation element 66 is connected to the display drive unit 50 and modulates the incident luminous flux based on the display drive signal from the display drive unit 50. The shift means 67 shifts the projected image in conjunction with the drive of the light modulation element 66 to shift the image formation position on the projected surface and control to improve the display resolution. The projection optical system 68 performs optical zoom (enlargement and reduction of the projected image), optical shift (movement of the position of the projected image on the projected surface), and focus adjustment by moving the lens and the unit by a motor. Is possible. Further, the projection optical system 68 can be replaced and attached by the user, and lenses having different image quality, angle of view, optical shift range, and the like can be selected according to the usage environment.

The operation unit 70 includes a button for inputting an operation by the user and an infrared light receiving unit for receiving infrared rays from the remote controller, and converts the input operation into an electric signal. Types of operations include decision and cancellation, menu calling for making various settings, up / down / left / right direction instructions, power supply control, and the like.

The communication unit 80 has a wired and wireless communication function, receives a command from an external device, and transmits a command from the projector 100 to the external device. When receiving a command, the CPU unit (control means) 30 performs processing equivalent to, for example, an operation input to the operation unit 70, and controls the image processing unit 10, the geometric distortion correction unit 40, the optical system 60, and the like. The communication unit 80 can also send and receive commands to and from other projectors and share information on various setting states such as image processing.

The sensor unit 84 includes a camera and a posture sensor, and is used as information for confirming the projected image and performing geometric deformation by taking an image of the projection surface and acquiring the posture state of the projector. The memory unit 90 stores various information such as values of various settings made by the user, information at the time of shipment of the projector, usage time, and logs. It also stores lens drive status, edge blending, geometric distortion correction, and other setting information related to shift drive range restrictions.

The CPU unit (control means) 30 includes an image processing unit 10, an OSD superimposing unit 20, a geometric distortion correction unit 40, a display drive unit 50, an operation unit 70, a communication unit 80, a sensor unit 84, a memory unit 90, and an optical system. It is connected to 60. In addition, the CPU unit 30 is also connected to a large number of devices (not shown) including a temperature sensor and a fan. The CPU unit 30 is also a microcomputer (processing unit) that controls the power supply and state of each part of the projector 100, and when an abnormality in the internal state is detected, the power supply is cut off, the light source is stopped, cooling is strengthened, and the user is notified. Processing such as warnings is also performed automatically. Further, the CPU unit 30 receives a user's operation input from the operation unit 70, performs control according to the operation, and also performs processing for a command received from the communication unit 80. For example, the CPU unit 30 controls the OSD superimposing unit 20 to display the menu screen, and controls the image processing unit 10, the geometric distortion correction unit 40, the projection optical system 68, and the like to control the state and function of each unit. Perform control, status acquisition, etc. Further, the CPU unit 30 can adjust the amount of light to the light source unit 62 in synchronization with the drive signal output from the display drive unit 50.

Next, with reference to FIG. 2, the lighting (display) operation (light amount control method) of the pixels (pixels on the screen) by the CPU unit 30 of this embodiment will be described. Each step in FIG. 2 is executed by the CPU unit 30 according to a computer program (control program). The flowchart of FIG. 2 is performed when the function for improving the moving image characteristics is effective, and is repeatedly executed in a loop of processing while the function is effective. Here, the moving image characteristic means that black insertion (black display) is performed during a predetermined period of a so-called one-frame period in order to improve the moving image visibility. The black display is an example, and includes a case where the display is darker than the normal display.

First, in step S10, the CPU unit 30 acquires information regarding the state of the shift operation of the shift means 67 (information regarding whether or not the shift operation period is in progress). The information regarding the state of the shift operation is, for example, the position information from the encoder of the shift means 67 as shown in FIG. FIG. 3 is a diagram showing an example of position information from the encoder, in which the vertical axis represents a relative position and the horizontal axis represents time. However, the information regarding the state of the shift operation in this embodiment is not limited to this, and may be other information such as a pulse signal when passing through a predetermined position.

Subsequently, in step S20, the CPU unit 30 classifies the pixel state (shift operation state). Classification is performed on the information acquired in step S10. The CPU unit 30 classifies pixel states (shift operation states) based on predetermined conditions. For example, the position information may be classified according to whether or not the position is within a predetermined range, the movement speed of the shift means 67, or the time using a timer, but the present invention is limited to these. It is not something that is done. In this embodiment, the CPU unit 30 determines the classification of the pixel state (state of shift operation) as information of either 0 (stable) or 1 (unstable) as a numerical value indicating the degree of stability of the pixel. Here, stable (first state) means a case where the pixel state (shift operation state) is within a predetermined range, and unstable (second state) means a pixel state (shift operation state). Means that is out of the predetermined range. More specifically, for example, in FIG. 3, the first state is a state in which the change in relative position with respect to a change in time is smaller than a predetermined amount, and the second state is a change in relative position with respect to a change in time. Is larger than the predetermined amount.

Subsequently, in step S30, the CPU unit 30 branches the process based on the classification performed in step S20. If the classification is 0 (stable), the process proceeds to step S40. On the other hand, when the classification is 1 (unstable), the process proceeds to step S50. In each of step S40 and step S50, the CPU unit 30 controls the amount of light (controls so that the amount of light of the lighting pixel changes) by performing signal processing by the display drive unit 50 and adjusting the amount of light of the light source unit 62. .. Here, step S40 is controlled so that the lighting pixels are brighter than those in step S50. When step S40 or step S50 is completed, this flow ends.

According to this embodiment, by classifying the pixel states and controlling the lighting state based on the classification, the moving image blurring caused by the hold display of the pixels and the displacement of the display position due to the shift operation. It is possible to reduce the influence of the reduction in resolution.

Next, Example 2 of the present invention will be described. In this embodiment, the configuration of the projector 100 is the same as that of the first embodiment, and only the processing performed by the CPU unit 30 is different from that of the first embodiment. Therefore, the description of the same configuration portion will be omitted.

With reference to FIG. 4, the lighting operation (light amount control method) of the pixels (pixels on the screen) by the CPU unit 30 of this embodiment will be described. Each step in FIG. 4 is executed by the CPU unit 30 according to a computer program (control program). Step S110 and step S120 of FIG. 4 are the same as steps S10 and S20 of FIG. 2 (Example 1), respectively, and the CPU unit 30 acquires information on the state of the shift operation, and the pixels are based on the information. Classify the state.

Subsequently, in step S130, the CPU unit 30 analyzes the movement amount and frequency component of the projected image. In this embodiment, the CPU unit 30 acquires statistical information of the input image signal from the image processing unit 10, multiplies the acquired numerical value by a predetermined coefficient, adds each of them, and has a weighting coefficient w (0 ≦ w ≦ 1). Ask for. The larger the weighting coefficient w, the larger the movement of the projected image, which means that the image contains high frequency components. Subsequent step S140 corresponds to step S30 of FIG. 2, and branches the process based on the result of step 120, and proceeds to step S150 or step S160.

In each of step 150 and step 160, the CPU unit 30 controls the amount of light of the lighting pixel in the same manner as in step S40 and step S50 of FIG. However, in this embodiment, the method for determining the amount of light is different from that in Example 1. In this embodiment, the CPU unit 30 controls the brightness of the lighting pixels based on the weighting coefficient w obtained in step S130. That is, the CPU unit 30 controls the amount of light so that the larger the weighting coefficient w, the larger the difference in brightness between steps S150 and S160. However, the CPU unit 30 determines the parameters so that the average brightness does not change in one subframe period. When step S150 or step S160 is completed, this flow ends.

According to this embodiment, by determining the brightness of the light and dark of the lighting pixel by referring to the statistical information of the input image signal, the influence of moving image blur and resolution reduction while suppressing the influence of flicker and color break due to the light and dark drive is suppressed. Can be reduced.

(Other Examples)
The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

As described above, the image projection device (projector 100) of each embodiment has a control means (CPU unit 30) and a shift means 67. The control means can control the amount of light of the pixels projected on the projected surface (screen). The shift means shifts the pixels in synchronization (interlocking) with the period of the subframe for forming one frame of the input image. Further, the control means changes the amount of light based on the state of the shift operation by the shift means.

Preferably, the control means forms pixel information corresponding to one frame of the input image by controlling the light source unit 62 or the image display element (light modulation element 66) according to the shift operation to control the amount of light of the pixels. do. Further, preferably, the control means controls the amount of light based on the position of the pixel that moves by the shift operation. Also preferably, the control means controls the amount of light based on the moving speed of the pixels that move due to the shift operation. Also preferably, the control means controls the amount of light based on the time of the shift operation.

Preferably, the control means sets the light intensity to a first light intensity (normal display, bright gain) or a second light intensity (black insertion, dark gain) based on the state of the shift operation. More preferably, the control means classifies the states into a plurality of states including a first state (stable state) and a second state (unstable state). Then, when the state is the first state, the control means sets the light amount to the first light amount. On the other hand, when the state is the second state, the control means sets the light amount to the second light amount. Also preferably, the control means acquires the amount of movement of the input image. Then, when the movement amount is the first movement amount, the control means controls the difference between the first light amount and the second light amount to the first amount. On the other hand, when the movement amount is the second movement amount larger than the first movement amount, the difference between the first light amount and the second light amount is controlled to the second amount larger than the first light amount. (Increase the degree of black, make it darker). Also preferably, the control means acquires high frequency components of the input image. Then, when the high frequency component is the first high frequency component, the control means controls the difference between the first light amount and the second light amount to the third amount. On the other hand, when the high frequency component is a second high frequency component having more than the first high frequency component, the control means has a fourth amount in which the difference between the first light amount and the second light amount is larger than the third amount. To control.

According to each embodiment, it is possible to provide an image projection device and a program capable of improving the resolution and the visibility of moving images by displaying pixels according to the state of shift operation.

Although preferable examples of the present invention have been described above, the present invention is not limited to these examples, and various modifications and changes can be made within the scope of the gist thereof.

In each embodiment, the case where the pixel shift is performed for the purpose of improving the display resolution has been described, but the purpose of the pixel shift may be another purpose such as reduction of the lattice feeling. Further, in each embodiment, the case of using the light modulation element has been described, but it may be applied to a different projection image generation method such as the case of using a DMD or an organic EL. Further, in each embodiment, the case where the pixel state (state of shift operation) is classified by two values has been described, but the classification may be finer, and it is determined as a continuous value and treated as a coefficient of the amount of lighting light. It may be configured.

30 CPU unit (control means)
62 Light source unit 66 Light modulation element (image display element)
67 Shift means 100 Projector (image projection device)

Claims (10)

Light source and
Image display element and
A control means that can control the amount of light of the pixels projected on the projected surface,
It has a shift means for shifting the pixels in synchronization with the period of the subframe for forming one frame of the input image.
The control means is an image projection device characterized in that the amount of light is changed based on the state of the shift operation by the shift means. The control means is characterized in that pixel information corresponding to one frame of an input image is formed by controlling the light source unit or the image display element in response to the shift operation to control the amount of light of the pixels. The image projection device according to claim 1. The image projection device according to claim 1 or 2, wherein the control means controls the amount of light based on the position of the pixel that moves by the shift operation. The image projection device according to any one of claims 1 to 3, wherein the control means controls the amount of light based on the moving speed of the pixels that move by the shift operation. The image projection device according to any one of claims 1 to 4, wherein the control means controls the amount of light based on the time of the shift operation. The image projection apparatus according to any one of claims 1 to 5, wherein the control means sets the light amount to a first light amount or a second light amount based on the state of the shift operation. .. The control means
The shift operation state is classified into a plurality of states including a first state and a second state.
When the state is the first state, the light amount is set to the first light amount, and the light amount is set to the first light amount.
The image projection apparatus according to claim 6, wherein when the state is the second state, the light amount is set to the second light amount. The control means
The amount of movement of the input image is acquired, and
When the movement amount is the first movement amount, the difference between the first light amount and the second light amount is controlled to be the first amount.
When the movement amount is a second movement amount larger than the first movement amount, the difference between the first light amount and the second light amount is larger than the first light amount. The image projection apparatus according to claim 6 or 7, wherein the amount is controlled. The control means
Obtain the high frequency component of the input image and
When the high frequency component is the first high frequency component, the difference between the first light amount and the second light amount is controlled to a third amount.
When the high-frequency component is a second high-frequency component having more than the first high-frequency component, the difference between the first light amount and the second light amount is set to a fourth amount larger than the third amount. The image projection apparatus according to any one of claims 6 to 8, wherein the image projection device is controlled. A step of acquiring the state of the shift operation by the shift means for shifting the pixels in synchronization with the period of the subframe for forming one frame of the input image, and
A program characterized by causing a computer to execute a step of changing the amount of light of the pixel based on the state of the shift operation.

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